U.S. patent application number 16/241736 was filed with the patent office on 2019-07-11 for ph and moisture indicator devices and formulations.
The applicant listed for this patent is Smith & Nephew PLC. Invention is credited to Sebastien Antoine Yves Cuvelier, Anthony Dagger, Nicholas Charlton Fry, Victoria Jody Hammond, Edward Yerbury Hartwell, John Kenneth Hicks, Alexander Speirs Laurie, Helene Anne Lecomte, Dorothy Mcculloch, Rhianna Moss, Ella Lynn Mumby, Mark Richardson, Carl Saxby, Benjamin Wicks.
Application Number | 20190212311 16/241736 |
Document ID | / |
Family ID | 67139452 |
Filed Date | 2019-07-11 |
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United States Patent
Application |
20190212311 |
Kind Code |
A1 |
Hammond; Victoria Jody ; et
al. |
July 11, 2019 |
PH AND MOISTURE INDICATOR DEVICES AND FORMULATIONS
Abstract
Disclosed herein are devices, wound dressings and methods for
determining the pH of fluid or a wound exudate at a wound. Example
devices include a device comprising a surface configured to contact
the fluid or wound and a pH indicator covalently bound thereto or
applied to the surface, wherein the pH indicator has a first colour
prior to contact with the fluid or the wound exudate and changes
colour as a function of the pH of the fluid or wound exudate.
Example devices include a device which indicates wound exudate
loading within a wound dressing and wound dressing comprising an
absorbent layer and a moisture indicator which indicates would
exudate loading within the dressing, wherein the visibility of the
moisture indictor changes as a result of a physical transformation
of a first material within the dressing. Systems, devices, and
methods are provided for monitoring wound status and progression by
measuring pH levels indicated by pH-sensitive wound dressings. In
some implementations, a wound is monitored by capturing an image of
the pH-sensitive wound dressing and processing the captured image
to determine the color of a pH indicator included on the wound
dressing. The color of the indicator is determined in terms of RGB
values from the image, and a pH value for the wound dressing is
calculated from the dressing RGB values. The calculated pH value is
then relayed to a user to be used as an indicator of wound status
or health.
Inventors: |
Hammond; Victoria Jody;
(Hull, GB) ; Hicks; John Kenneth; (Pocklington,
GB) ; Hartwell; Edward Yerbury; (Hull, GB) ;
Mcculloch; Dorothy; (Heslington, GB) ; Richardson;
Mark; (Grimsby, GB) ; Saxby; Carl; (Brough,
GB) ; Dagger; Anthony; (York, GB) ; Fry;
Nicholas Charlton; (Pocklington, GB) ; Laurie;
Alexander Speirs; (Melbourn, GB) ; Lecomte; Helene
Anne; (York, GB) ; Moss; Rhianna; (Heslington,
GB) ; Mumby; Ella Lynn; (Hull, GB) ; Cuvelier;
Sebastien Antoine Yves; (Haverhill, GB) ; Wicks;
Benjamin; (Cambridge, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Smith & Nephew PLC |
London |
|
GB |
|
|
Family ID: |
67139452 |
Appl. No.: |
16/241736 |
Filed: |
January 7, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15804748 |
Nov 6, 2017 |
10288590 |
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16241736 |
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14650547 |
Jun 8, 2015 |
9829471 |
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PCT/EP2014/071520 |
Oct 8, 2014 |
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15804748 |
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14650531 |
Jun 8, 2015 |
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PCT/EP2014/071510 |
Oct 8, 2014 |
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14650547 |
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14893361 |
Nov 23, 2015 |
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PCT/GB2014/051574 |
May 22, 2014 |
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14650531 |
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14759786 |
Jul 8, 2015 |
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PCT/GB2014/050048 |
Jan 9, 2014 |
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14893361 |
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15113775 |
Jul 22, 2016 |
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PCT/EP2015/050964 |
Jan 20, 2015 |
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14759786 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01N 27/4165 20130101;
G01N 21/80 20130101; A61B 5/0077 20130101; A61B 5/6833 20130101;
A61B 5/1495 20130101; A61B 5/14539 20130101; G01N 31/221 20130101;
A61F 13/42 20130101; A61B 5/0013 20130101; A61F 2013/427 20130101;
G01N 31/222 20130101; A61B 5/445 20130101 |
International
Class: |
G01N 31/22 20060101
G01N031/22 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 11, 2013 |
GB |
1300470.0 |
May 24, 2013 |
GB |
1309369.5 |
Oct 8, 2013 |
GB |
1317742.3 |
Oct 8, 2013 |
GB |
1317746.4 |
Jan 23, 2014 |
GB |
1401112.6 |
Claims
1. A device for determining the pH of a fluid, the device
comprising a fluid-contacting surface having a pH indicator
covalently immobilised thereon, wherein the pH indicator has a
first colour prior to contact with the fluid and changes colour as
a function of the pH of the fluid.
2. The device according to claim 1, wherein the colour change in
the pH indicator is detectable at a 0.1 unit interval change in
pH.
3. The device according to claim 2, wherein the colour change in
the pH indicator is detectable between about pH 5 and about pH
10.
4. The device according to claim 3, wherein the colour change in
the pH indicator is detectable between about pH 5.5 and about pH
9.5.
5. The device according to claim 3, wherein the colour change in
the pH indicator is detectable between about pH 6.5 and 9.5.
6. The device according to claim 1, wherein the pH indicator
comprises aphenylazo compound.
7. The device according to claim 6, wherein the phenylazo compound
is selected from the group listed in Table 1.
8. The device according to claim 6, wherein the pH indicator
comprises a combination of phenylazo compounds.
9. The device according to claim 1, wherein the device comprises a
cellulosic material.
10. A device comprising: (a) a fluid-contacting surface, (b) an
opposing non-fluid contacting surface, (c) a pH indication zone
comprising a pH indicator covalently bound therein, which indicates
the pH of a fluid, wherein the colour of the pH indicator changes
in response to a change in the pH of the fluid; and, (d) at least
one conduit for directing fluid towards the pH indication zone.
11. The device according to claim 10, wherein the device has an
outer surface and wherein a pH indication zone is located at or
near the outer surface.
12. The device according to claim 11, wherein the device has a
peripheral edge extending between the fluid-contacting surface and
the opposing non-fluid contacting surface and wherein the outer
surface is the peripheral edge.
13. The device according to claim 10, wherein the at least one
conduit directs fluid laterally towards the pH indication zone.
14. The device according to claim 10, wherein the colour change in
the pH indicator is detectable at a 0.1 unit interval change in
pH.
15. The device according to claim 14, wherein the colour change in
the pH indicator is detectable between about pH 5 and about pH
10.
16. The device according to claim 15, wherein the colour change in
the pH indicator is detectable between about pH 5.5 and about pH
9.5.
17. The device according to claim 15, wherein the colour change in
the pH indicator is detectable between about pH 6.5 and about pH
9.5.
18. The fluid dressing according to claim 10, wherein the pH
indicator comprises a phenylazo compound.
19. The device according to claim 18, wherein the phenylazo
compound is selected from the group listed in Table 1.
20. The device according to claim 18, wherein the pH indicator
comprises a combination of phenylazo compounds.
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Description
BACKGROUND SECTION 1 ENTITLED PH INDICATOR DEVICE AND
FORMULATION
[0001] Section 1 and FIGS. 1-17 of this application contain the
disclosure of application Ser. No. 15/804,748, titled "pH Indicator
Device and Formulation," filed Nov. 6, 2017, published as US
2018/0196021, which is a continuation of application Ser. No.
14/650,547, filed Jun. 8, 2015 published as US 2015/0308994 and
patented as U.S. Pat. No. 9,829,471, which is a national phase
entry of PCT/EP2014/071520 filed Oct. 8, 2014 which claims priority
to GB 1317746.4 filed Oct. 8, 2013, all of which are incorporated
by reference in their entirety.
[0002] The need to reliably test the pH of a fluid sample is a
requirement in a plethora of industries, particularly where the pH
is indicative of potential quality, safety or health concerns. pH
measurements are important in, for example, medicine, biology,
chemistry, agriculture, forestry, food science, environmental
science, oceanography, civil engineering, chemical engineering,
nutrition, water treatment and water purification.
[0003] The pH of water is routinely tested. The pH of drinking
water is routinely monitored to ensure that it is safe to drink,
whereas the water in swimming pools is routinely tested to ensure
that it is safe to swim in. Monitoring alterations in the pH of
fish ponds or river water can be indicative of environmental
pollution. In agriculture and horticulture, knowledge of the pH of
the soil is not only instructive in the selection of suitable crops
but also discerns whether there arc local environmental issues,
such as pollution. In the food and brewing industries, maintaining
a proper pH range is essential in many of the physical and chemical
reactions that take place during food and drink processing.
Monitoring the pH of bodily fluids can be a useful diagnostic. For
example, it has been demonstrated that the pH of saliva can predict
susceptibility to a range of diseases, including cancer, heart
disease and osteoporosis.
[0004] pH testing is conventionally performed using pH meters, but
these are impractical for a variety of applications as they require
regular calibration using standard buffer solutions. Furthermore,
the glass electrodes are fragile and must be kept constantly wet,
normally in an acidic solution, in order to avoid dehydration of
the pH sensing membrane and subsequent dysfunction of the
electrode. Disposable pH test strips are available, but due to the
permanence of the colour change as a function of pH of the test
sample, the strips are unable to demonstrate any changes in pH over
time. Additionally, the disposable characteristic adds to the cost
implications.
[0005] A need exists for a device which enables the real-time,
reversible and stable detection of pH in a fluid.
BACKGROUND SECTION 2 ENTITLED PH INDICATOR DRESSING
[0006] Section 2 and FIGS. 18-27 of this application contain the
disclosure of application Ser. No. 14/650,531, titled "pH Indicator
Dressing" filed Jun. 8, 2015, published as US 2016/0262672, which
is a national phase entry of PCT/EP2014/071510 filed Oct. 8, 2014
which claims priority to GB 1317742.3 filed Oct. 8, 2013, all of
which are incorporated by reference in their entirety.
[0007] The field of wound care management has long understood that
the pH of a wound can be an indication of wound healing status and
can indicate when further action may be necessary to aid wound
healing. The pH can affect many factors including oxygen release,
angiogenesis, protease activity and bacterial toxicity. Acute and
chronic wounds with an elevated alkaline pH have been shown to have
lower rates of healing than wounds in which the pH is closer to
neutral. For example, if a chronic wound has a pH of between 6 to
7.5 this indicates that wound healing is progressing well. In
comparison, if the pH is between 7.5 and 8, this indicates that the
wound should be monitored and a pH of above 8 indicates that
clinical intervention is required. It is therefore important to be
able to monitor wound pH in order to be able to assess wound
healing and intervene, if necessary.
[0008] Some current wound dressings utilize a pH indicator dye
provided on a colour strip integrated within the dressing. The dye
changes colour (e.g., from yellow to purple) if the pH value is
between 6.5 and 8.5, an indication of an infected wound. The dye is
not sufficiently sensitive to provide an indication of the
incremental change in pH between 6.5 and 8.5. Additionally, the dye
does not provide an indication of the pH at the wound surface but
rather the pH of the wound exudate at the point in the dressing
where it is measured. As the pH of wound exudate can be affected by
numerous external factors, including the composition of the
dressing itself, the measurement of the pH of wound exudate at any
significant distance away from the wound surface is often
inaccurate. Whilst a pH probe allows direct measurement of the pH
at the wound surface, its use can result in tissue disruption and
localised cell death, such that the probe requires regular
calibration. Moreover, the measurement only provides a snap-shot of
the pH of a specific area of the wound at a single point in time
and provides no indication of the pH changes over time.
BACKGROUND SECTION 3 ENTITLED MOISTURE INDICATING SYSTEM
[0009] Section 3 and FIGS. 28-32 of this application contain the
disclosure of application Ser. No. 14/893,361, titled "Moisture
Indicating System" filed Nov. 23, 2015, published as US
2016/0100987, which is a national phase entry of PCT/GB2014/051574
filed May 22, 2014 which claims priority to GB 1309369.5 filed May
24, 2013, all of which are incorporated by reference in their
entirety.
[0010] The field of wound care management has long understood that
keeping wounds optimally moist can help the cells in the wound area
grow and migrate to the proper location to help the wound heal.
Achieving an optimal moist environment relies on good clinical
judgement to determine the correct moisture levels, since too
little moisture can desiccate the wound and too much can lead to
maceration of the wound bed and surrounding tissue. It is therefore
important to be able to monitor moisture, to properly and optimally
change the bandage, while still allowing the wound to heal
undisturbed. Common techniques for performing such monitoring rely
on visual indications of excess moisture or strikethrough on wound
dressings. Commonly used indications include visual changes on
backing materials or leakage from the dressing.
[0011] Some current wound dressings utilize an indicator layer
containing a dye which changes colour on contact with wound
exudate. A typical dye is gentian violet, which changes from violet
to purple when wet, indicating that the dressing is saturated. That
change is typically hard to perceive and therefore users often find
it unreliable. Other current wound dressings, for example the
DuoDerm.RTM. Signal dressing sold by Convatec, rely on fluid
leaking from the wound into an area behind an impermeable outer
covering of the dressing, causing a blister to become visible. Once
the edge of the blister reaches an indicator line marked on the
outer surface of the dressing changing is required. As the
indicator is merely a blister on the surface of the dressing, it is
often difficult to read. Additionally, the blister can enlarge and
fill with fluid that exceeds the requirements of a healing
environment and fosters an environment for bacterial colonization.
There is a need in the art for a moisture indicating wound dressing
in which the moisture indicator within the dressing provides more
sensitive moisture detection with a more ascertainable signal to
the user.
BACKGROUND SECTION 4 ENTITLED MOISTURE INDICATOR DRESSING
[0012] Section 4 and FIGS. 33-37 of this application contain the
disclosure of application Ser. No. 14/759,786, titled "Moisture
Indicating Dressing" filed Jul. 8, 2015, published as US
2015/0351970, which is a national phase entry of PCT/GB2014/050048
filed Jan. 9, 2014 which claims priority to GB 1300470.0 filed Jan.
11, 2013, all of which are incorporated by reference in their
entirety.
[0013] There is a need in the art for a moisture indicating wound
dressing in which the moisture indicator within the dressing
provides a more ascertainable signal to the user. Further, there is
a need in the art for a dressing in which the user is able to
monitor the moisture levels within different parts of the dressing.
Negative pressure wound therapy (NPWT) is a therapeutic technique
that utilizes a vacuum dressing to promote wound healing,
particularly in chronic wounds. The continued vacuum draws out
fluid from the wound and increases blood flow to the area. There is
a need to be able to determine within a NPWT system if any part of
the fluid outlet tube which is concealed within the dressing has a
leak, as this would result in sub-optimal therapy.
BACKGROUND SECTION 5 ENTITLED SYSTEMS AND METHODS FOR WOUND
MONITORING
[0014] Section 5 and FIGS. 38-50 of this application contain the
disclosure of application Ser. No. 15/113,775, titled "Systems and
Methods for Wound Monitoring" filed Jul. 22, 2016, published as US
2017/000407, which is a national phase entry of PCT/EP2015/050964
filed Jan. 20, 2015 which claims priority to GB 1401112.6 filed
Jan. 23, 2014, all of which are incorporated by reference in their
entirety.
[0015] Wound treatment often involves monitoring a wound during
healing for indications of the status and progress of the wound.
Monitoring indications of wound health can indicate the efficacy of
delivered treatment or signal to a physician a need for a change in
treatment. One indicator in particular that is useful for this
monitoring is the pH level of the wound tissue. The pH of the
tissue can indicate or affect a number of factors relevant to wound
healing, such as oxygen release, angiogenesis, protease activity,
and bacterial toxicity. For example, wounds having elevated
alkaline pH levels have been shown to have lower rates of healing
than wounds in which the pH is closer to or below a neutral 7.0 pH
level. For example, if a chronic wound has a pH between 6 and 7.5,
this often indicates that wound healing is progressing well and
treatment is working. If the pH rises to between 7.5 and 8.5, this
can be an indication that the wound should be monitored and
treatment adjusted to lower the pH level. By monitoring this pH
level over the course of the wound healing, a physician may be
better able to assess whether healing is progressing well or
whether intervention or a change in treatment is needed.
[0016] Direct measurement of wound pH levels, for example using a
pH pRGBe or applying a color sensitive pH strip, may be unsuitable
for pH monitoring during wound healing. The use of a pRGBe or strip
may disrupt or irritate the wound and hamper wound healing. To
facilitate wound monitoring, a pH-sensitive bandage may be provided
that changes color as the pH of the wound changes. These bandages
can be a quick and easy indication to a patient or a physician of
the pH of the wound to which the bandage is applied, and the
changing color of the wound dressing can provide a signal that the
pH of that wound is changing. While these bandages provide helpful
indications, interpretation of the color indicators is reliant on
the subjective assessment of the patient or physician. Often that
subjective judgment involves comparing the color of the dressing to
a standard color strip or scale and estimating where on the scale
the indicated pH falls. As a result, the assessment and judgment is
often limited in accuracy and resolution. The color determination
may also be hampered by differences in color perception between
individuals, differences in lighting conditions when a bandage is
assessed, color blindness, or other conditions that affect color
perception.
SUMMARY SECTION 1
[0017] Section 1 of this application discloses devices and methods
related to devices having pH indicators for monitoring the pH of a
fluid. Other advantages and improvements will be apparent to one of
skill in the art upon review of the application.
[0018] In one aspect, a device is provided for determining pH of a
fluid sample. The device preferably includes a surface configured
to contact the fluid and a pH indicator covalently immobilised
thereon, wherein the pH indicator has a first colour prior to
contact with the fluid and changes colour along a colour spectrum
as a function of the pH of the fluid. In embodiments, the pH
indicator changes colour in response to change in pH and this
colour change is detectable at, for example, intervals of about a
0.1 unit, about 0.2 unit, about 0.3 unit about 0.4 unit or about
0.5 unit interval of pH. It is envisaged that the detection level
will vary based on the type of detection means utilised. For
example, an electronic detector such as a colour meter capable of
detecting changes in colour of light, has the capability to detect
a 0.1 unit change in pH. In comparison, the human eye is only
capable of visually detecting a colour change which is associated
with about a 0.5 unit change in pH. In embodiments, the pH
indicator utilised in the device is able to detect the pH between
about pH 0 and about pH 14 and indicates changes in pH by way of a
colour change along a colour spectrum, with each colour in the
spectrum being associated with a particular pH. In embodiments, the
pH indicator is able to detect a pH between about pH 5.0 and about
pH 10.0. In embodiments, the pH indicator is able to detect a pH
between about pH 5.5 and about pH 9.5. More particularly the pH
indicator is able to detect a pH between about pH 6.5 and about pH
9.5. Suitable pH indicators include phenylazo compounds such as
those listed in Table 1 which are available from Fraunhofer EMFT,
Germany.
TABLE-US-00001 TABLE 1 Phenylazo compounds Code Chemical name
GJM-514 2-[4(2-hydroxyethylsulfonyl)-phenyl]diazenyl]-4-
methylphenol GJM-546
1-hydroxy-4-[4[(hydroxyethylsulphonyl)-phenylazo]-
napthalene-2-sulphonate GJM-492
2-fluoro-4-[4[(2-hydroxyethanesulphonyl)-phenylazo]-6- methoxy
phenol GJM-534 4-[4-(2-hydroxyethylsulphonyl)-phenylazo]-2,6-
dimethoxyphenol
[0019] In some embodiments, the pH indicator is a triarylmethane
dye. In some embodiments, the pH indicator is a fluorescent
dye.
[0020] In embodiments, the pH indicator comprises a combination of
compounds which allows a broader pH range to be detected than can
be detected by use of a single compound. For example, the pH
indicator comprises a combination of phenylazo compounds. In
embodiments, the combination comprises at least two phenylazo
compounds selected from the group listed in Table 1. In embodiments
the combination comprises at least three phenylazo compounds
selected from the group listed in Table 1. In embodiments, the
combination comprises at least one phenylazo compound selected from
the group listed in Table 1 and at least one compound that is not a
phenylazo compound. In embodiments, derivatives or modifications of
the phenylazo compounds listed in Table 1 are envisaged.
[0021] In embodiments, the device is a cellulosic material, for
example a cellulose pad. In embodiments, the device is a non-woven
mesh or perforated film.
[0022] In some embodiments, the fluid is a liquid. Non-limiting
examples includes water. In some embodiments, the fluid is a gas,
for example for use in a face mask. In some embodiments, the fluid
is a moisture. Non-limiting examples include the moisture
associated with a soil sample. In some embodiments, the fluid is a
bodily sample. Non-limiting examples include, saliva, urine, blood,
sweat/perspiration.
[0023] In another aspect, a device is provided for determining pH
of a fluid sample. The device preferably includes: (a) a
fluid-contacting surface, (b) an opposing non-fluid contacting
surface, (c) a pH indication zone comprising a pH indicator
covalently immobilised therein which indicates the pH of a fluid,
wherein the colour of the pH indicator changes in response to a
change in the pH of the fluid, and (d) at least one conduit for
directing fluid towards the pH indication zone. The conduit helps
direct fluid toward the pH indicator without materially altering
the pH en route to the indicator. In certain embodiments, the
material of the conduit contains no acid or base functionality,
that is to say, it is neutral and can not remove any acid or base
entities from the fluid until it reaches the pH indicating system.
In certain embodiments, the device has an outer surface and the pH
indication zone is located at or near the outer surface. In other
embodiments, the device has a peripheral edge extending between the
fluid contacting surface and the opposing non-fluid contacting
surface and pH indication zone is located at or near to this
peripheral edge. In certain embodiments, the conduit directs fluid
laterally towards the pH indication zone. In embodiments, the pH
indicator changes colour in response to change in pH and this
colour change is detectable at, for example, intervals of about a
0.1 unit, about 0.2 unit, about 0.3 unit about 0.4 unit or about
0.5 unit interval of pH. It is envisaged that the detection level
will vary based on the type of detection means utilised. For
example, an electronic detector such as a colour meter has the
capability to detect a 0.1 unit change in pH. In comparison, the
human eye is only capable of visually detecting a colour change
which is associated with about a 0.5 unit change in pH. In
embodiments, the pH indicator utilised in the device is able to
detect the pH between pH 0 and 14 and indicates changes in pH by
way of a colour change along a colour spectrum, with each colour in
the spectrum being associated with a particular pH. In embodiments,
the pH indicator is able to detect pH between about pH 5 and about
pH10. Particularly, the pH indicator is able to detect pH between
about pH 5.5 and about pH 9.5. More particularly, the pH indicator
is able to detect pH between about pH 6.5 and about pH 9.5.
Suitable pH indicators include phenylazo compounds such as those
selected from the group listed in Table 1. In embodiments, the pH
indicator comprises a combination of compounds which allows a
broader pH range to be detected than can be detected by use of a
single compound. For example, the pH indicator comprises a
combination of phenylazo compounds. In embodiments, the combination
comprises at least two phenylazo compounds selected from the group
listed in Table 1. In embodiments, the combination comprises at
least three phenylazo compounds selected from the group listed in
Table 1. In embodiments, the combination comprises at least one
phenylazo compound selected from the group listed in Table 1 and at
least one compound that is not a phenylazo compound. In
embodiments, derivatives or modifications of the phenylazo
compounds listed in Table 1 are envisaged.
[0024] In a further aspect, a formulation is provided for
indicating pH of a fluid. Advantageously, the pH indicator is
covalently immobilised within the formulation and is therefore not
washed away by the fluid upon contact. The formulation preferably
includes a dye that functions as a pH indicator. The dye may
include a phenylazo compound, where the colour of the phenylazo
compound changes in response to a change in the pH of the fluid. In
embodiments, the pH dye changes colour in response to a 0.5 unit
interval change in pH. For example, the pH indicator has a
different colour for each 0.5 unit interval change in pH. The pH
indicator utilised in the device is able to detect the pH between
pH 5 and 10, particularly between pH 5.5 and 9.5 and more
particularly between pH 6.5 and 9.5. Suitable pH indicators include
phenylazo compounds such as those selected from the group listed in
Table 1. In embodiments, the pH indicator comprises a combination
of compounds which allows a broader pH range to be detected than
can be detected by use of a single compound. For example, the pH
indicator comprises a combination of phenylazo compounds. In
embodiments, the combination comprises at least two phenylazo
compounds selected from the group listed in Table 1. In
embodiments, the combination comprises at least three phenylazo
compounds selected from the group listed in Table 1. In
embodiments, the combination comprises at least one phenylazo
compound selected from the group listed in Table 1 and at least one
compound that is not a phenylazo compound.
[0025] In embodiments, derivatives or modifications of the
phenylazo compounds listed in Table 1 are envisaged. In
embodiments, the formulation is applied to a device for use in
detecting pH at the point of manufacture. In embodiments, the
formulation is an adhesive. In embodiments, the adhesive is a low
tack adhesive, for example a silicon adhesive. In other
embodiments, it is envisaged that the formulation is a gel, for
example, a conformable semi-rigid or rigid gel, that does not
disintegrate upon contact with the fluid to be tested. The
formulation can be used in a device according to the first and/or
second aspect.
[0026] In another aspect, a method is provided for monitoring the
pH of a fluid. The method preferably comprises the steps of: (a)
providing a device comprising a surface configured to contact the
fluid, said surface having a pH indicator covalently bound thereto,
wherein the pH indicator has a first colour prior to contact with
the fluid and changes colour as a function of the pH of the fluid,
(b) contacting the device with the fluid, (c) assessing the colour
of the pH indicator. It is envisaged that the method can be
utilised in numerous applications in which the knowledge of the pH
of a fluid sample is paramount to determining quality control or
safety. Non-limiting examples of potential applications include:
food storage; packaging spoilage indicators; wine; brewing;
analysis of drinking water, swimming pool water, river water or
fish ponds; agriculture and horticulture; clothing, for example
perspiration analysis; in-line monitoring of processes, gases,
liquids; skin care--medical (dermatology) or cosmetic; coatings of
containers and surfaces to detect changes/inconsistencies;
monitoring drug release or stability.
[0027] In a further aspect, a device comprises a fluid contacting
surface having a pH indicating means covalently bound thereto,
wherein the pH indicating means has a first colour prior to contact
with a fluid and changes colour as a function of the pH of the
fluid.
[0028] In another aspect a device comprises a pH indicating means,
wherein the pH indicating means has a first colour prior to contact
with a fluid and changes colour as a function of the pH of the
fluid and a conduit means for directing the fluid towards the pH
indicating means.
SUMMARY SECTION 2
[0029] Section 2 of this application discloses devices and methods
related to wound dressings having pH indicators for monitoring the
pH at the wound surface. The disclosure also includes dressings in
which the user is able to visually monitor incremental changes in
the pH of the wound over time, using a pH scale. To monitor the pH,
the pH indicator changes visually (e.g., by changing colour) as a
function of the pH of the wound exudate. This provides a visual
indication of the wound's pH status and enables an assessment to be
made a-; to whether any therapeutic intervention is required in
order to facilitate healing. Other advantages and improvements will
be apparent to one of skill in the art upon review of the
application.
[0030] In embodiments, the device is a conformable, non-woven mesh
or perforated film. The device can be provided in a range of sizes
suitable to fit or cover a wound. Alternatively, the device can be
cut to fit or cover the wound. Devices which fit or cover the wound
enable the pH to be mapped across the wound rather than at selected
locations. This is particularly advantageous as the pH of the wound
is often not uniform across the wound. In alternative embodiments,
the device can be used in isolation and placed in the wound between
dressing changes in order to detect the pH of the wound. For
example, the device can be incorporated into a dipstick format that
can be placed into the wound between dressing changes.
Alternatively, the device can be used in conjunction with a
secondary wound dressing of the clinician's choice. In that
scenario, the pH is assessed upon application to and removal of the
device/secondary dressing from the wound. In embodiments, the
device is positioned at or near a lower surface of the dressing. In
certain embodiments, the device is the wound contacting layer of
the secondary dressing.
[0031] In another aspect, a wound dressing is provided with a pH
indicator. The pH indicator preferably includes: (a) a
wound-contacting surface, (b) an opposing non-wound contacting
surface, (c) a pH indication zone comprising a pH indicator which
indicates the pH of a wound exudate, wherein the colour of the pH
indicator changes in response to a change in the pH of the wound
exudate, and (d) at least one conduit for directing wound exudate
towards the pH indication zone. The conduit helps direct wound
exudate toward the pH indicator without materially altering the
exudate pH en route to the indicator. In certain embodiments, the
material of the conduit contains no acid or base functionality,
that is to say, it is neutral and cannot remove any acid or base
entities from the exudate until it reaches the pH indicating
system. In certain embodiments, the wound dressing has an outer
surface and the pH indication zone is located at or near the outer
surface. In other embodiments, the dressing has a peripheral edge
extending between the wound-contacting surface and the opposing
non-wound contacting surface and pH indication zone is located at
or near to this peripheral edge. In certain embodiments, the
conduit directs wound exudate laterally towards the pH indication
zone. In embodiments, the pH indicator changes colour in response
to change in pH and this colour change is detectable at, for
example, intervals of about a 0.1 unit, about 0.2 unit, about 0.3
unit about 0.4 unit or about 0.5 unit interval of pH. It is
envisaged that the detection level will vary based on the type of
detection means utilised. For example, an electronic detector such
as a colour meter has the capability to detect a 0.1 unit change in
pH. In comparison, the human eye is only capable of visually
detecting a colour change which is associated with about a 0.5 unit
change in pH. In a wound care setting, wound exudate pH can be
detected across a broad range. In embodiments, the pH indicator
utilised in the device is able to detect the pH between pH 5 and 10
and indicates changes in pH by way of a colour change along a
colour spectrum, with each colour in the spectrum being associated
with a particular pH. In embodiments, the pH indicator is able to
detect wound pH between about pH 5 and about pH 10. Particularly,
the pH indicator is able to detect wound pH between about pH 5.5
and about pH 9.5. More particularly, the pH indicator is able to
detect wound pH between about pH 6.5 and about pH 9.5. Suitable pH
indicators include phenylazo compounds such as those selected from
the group listed in Table 1. In embodiments, the pH indicator
comprises a combination of compounds which allows a broader pH
range to be detected than can be detected by use of a single
compound. For example, the pH indicator comprises a combination of
phenylazo compounds. In embodiments, the combination comprises at
least two phenylazo compounds selected from the group listed in
Table 1. In embodiments, the combination comprises at least three
phenylazo compounds selected from the group listed in Table 1. In
embodiments, the combination comprises at least one phenylazo
compound selected from the group listed in Table 1 and at least one
compound that is not a phenylazo compound. In embodiments,
derivatives or modifications of the phenylazo compounds listed in
Table 1 are envisaged.
[0032] In a further aspect, a formulation is provided for
indicating pH of a wound exudate. The formulation preferably
includes a dye that functions as a pH indicator. The dye may
include a phenylazo compound, where the colour of the phenylazo
compound changes in response to a change in the pH of the wound
exudate. In embodiments, the pH dye changes colour in response to a
0.5 unit interval change in pH. For example, the pH indicator has a
different colour for each 0.5 unit interval change in pH. The pH
indicator utilised in the dressing is able to detect the pH between
pH 5 and 10, particularly between pH 5.5 and 9.5 and more
particularly between pH 6.5 and 9.5. Suitable pH indicators include
phenylazo compounds such as those selected from the group listed in
Table 1. In embodiments, the pH indicator comprises a combination
of compounds which allows a broader pH range to be detected than
can be detected by use of a single compound. For example, the pH
indicator comprises a combination of phenylazo compounds. In
embodiments, the combination comprises at least two phenylazo
compounds selected from the group listed in Table 1. In
embodiments, the combination comprises at least three phenylazo
compounds selected from the group listed in Table 1. In
embodiments, the combination comprises at least one phenylazo
compound selected from the group listed in Table 1 and at least one
compound that is not a phenylazo compound. In embodiments,
derivatives or modifications of the phenylazo compounds listed in
Table I are envisaged. In embodiments, the formulation is applied
to a device for use in detecting pH at the point of manufacture. In
embodiments, the formulation is an adhesive. In embodiments, the
adhesive is a low tack adhesive, for example a silicon adhesive. In
embodiments, the adhesive is applied to the wound contacting
surface of the device. In other embodiments, it is envisaged that
the formulation is a gel, for example, a conformable semi-rigid or
rigid gel, that is placed into the wound to detect pH and which can
be removed from the wound intact. In embodiments, the gel is based
on chitosan or carboxymethylcellulose. The formulation can be used
in a device and/or a wound dressing according to the first and/or
second aspect.
[0033] In another aspect, a method is provided for monitoring the
pH of a wound. The method preferably comprises the steps of: (a)
providing a device comprising a surface configured to contact the
wound, said surface having a pH indicator applied thereto, wherein
the pH indicator has a first colour prior to contact with the wound
exudate and changes colour as a function of the pH of the wound
exudate, (b) applying the device to the wound, (c) assessing the
colour of the pH indicator. In certain embodiments the method
further includes the step of combining the device with a secondary
dressing prior to applying the device to the wound. In embodiments
of the method, the step of combining the device and the secondary
dressing includes adhering the device to the secondary dressing. In
certain embodiments, the device forms the wound contacting surface
of the secondary dressing. In some embodiments the method
additionally includes the step of removing the device (or secondary
dressing), inverting the device (or secondary dressing) so that the
device becomes visible and then assessing the colour of the pH
indicator. In this way a pH map of the wound bed may be generated.
Such maps may indicate zones of differing pH across the surface of
the wound.
[0034] In a further aspect, a wound dressing comprises a wound
contacting surface having a pH indicating means wherein the pH
indicating means has a first colour prior to contact with the wound
exudate and changes colour as a function of the pH of the wound
exudate.
[0035] In another aspect a wound dressing comprises a pH indicating
means, wherein the pH indicating means has a first colour prior to
contact with wound exudate and changes colour as a function of the
pH of the wound exudate and a conduit means for directing the wound
exudate towards the pH indicating means.
SUMMARY SECTION 3
[0036] Section 3 of this application discloses devices and methods
related to wound dressings having moisture indicators. The
underlying mechanism for monitoring the wound exudate loading
within a wound dressing utilises a colour change of a pH indicator
provided within the dressing. The colour change is driven by the
increased acidity or alkalinity of a wound exudate as it migrates
through the dressing. This alteration in the pH of the wound
exudate is a consequence of the exudate dissolving a soluble
composition which is provided within the dressing and which
consequently releases hydrogen or hydroxide ions into the wound
exudate. The modified wound exudate, loaded with the hydrogen or
hydroxide ions, has a pH which is either more acidic or more
alkaline than the unmodified wound exudate. As a result, the
modified wound exudate causes a more amplified change in the colour
of the pH indicator than would be caused by the unmodified wound
exudate. A device is disclosed which includes (i) a soluble
composition capable of releasing hydrogen or hydroxide ions upon
solubilisation and (ii) a colour-based pH indicator, wherein the
colour of the pH indicator is correlated to a pH The device can be
used in combination with a conventional wound dressing.
Alternatively, the device can be manufactured as a component of a
wound dressing. The colour change of the pH indicator provides a
visual indication of the wound exudate loading within the dressing.
A colour change is indicative of the wound exudate reaching the
part of the dressing where the device is located.
[0037] In one aspect, a device includes a first composition which
has a first colour and which changes to a second colour in response
to a change in pH and a second composition which dissolves upon
contact with a wound exudate to release hydrogen or hydroxide ions,
the wound exudate loaded with the released hydrogen or hydroxide
ions interacts with the first composition to cause the change to
the second colour. In certain embodiments, the first and second
compositions are impregnated into different carrier materials
within the device. In certain embodiments, the carrier materials
are physically separated by a spacer material. In certain
embodiments, the first and second compositions are impregnated into
the same carrier material within the device. In certain
embodiments, the first and second compositions which are
impregnated within the same carrier material are physically
separated, for example, at least one of the first or second
compositions is encapsulated in a soluble barrier which dissolves
upon contact with wound exudate to enable interaction between the
compositions.
[0038] In another aspect, a wound dressing is disclosed which
includes a device which indicates wound exudate loading. The device
includes: a first composition which has a first colour and which
changes to a second colour in response to pH, and a second
composition which dissolves upon contact with a wound exudate to
release hydrogen or hydroxide ions into the wound exudate and
wherein the wound exudate loaded with the hydrogen or hydroxide
ions causes the first composition to change to the second colour.
In certain embodiments, the wound dressing includes an absorbent
layer which has a wound-facing surface and an opposing
non-wound-facing surface, and the device is positioned within the
dressing such that the device is in contact with the
non-wound-facing surface of the absorbent layer. In certain
embodiments, the wound dressing has a peripheral edge and the
device extends outwardly from the peripheral edge. In certain
embodiments, the device forms an annular flange or annular ring,
which partially or fully encircles the peripheral edge of the
dressing.
[0039] In another aspect, a device is disclosed which indicates
wound exudate loading within a wound dressing. The device includes
a pH-dependent moisture indicating means and a means of generating
ions. Contact between the wound exudate and the means of generating
results in a wound exudate which is loaded with ions and which
interacts with the pH-dependent moisture indicating means to cause
a visual change. In certain embodiments, the ions generated are
hydrogen or hydroxide ions. In certain embodiments, the visual
change is a colour change from a first colour to a second
colour.
[0040] In a further aspect, a device is disclosed which indicates
wound exudate loading within a wound dressing, the device includes
a first composition which transforms from a first state to a second
state and a second composition which dissolves upon contact with
the wound exudate and which forces the transformation of the first
composition from the first state to the second state upon contact
therewith. In certain embodiments, the first state is a first
colour and the second state is a second colour. In certain
embodiments, the second composition releases ions into the wound
exudate to alter analyte levels within the wound exudate. In
certain embodiments, the wound exudate with released ions causes a
change to the second state.
[0041] In another aspect, methods are disclosed for monitoring
loading of a wound dressing by a wound exudate. The methods include
steps of (a) locating a first composition within the wound
dressing, wherein the first composition has a first colour prior to
contact with the wound exudate and which changes to a second colour
in response to a pH change; (b) locating a second composition
within the wound dressing, wherein the second composition dissolves
upon contact with a wound exudate to release hydrogen or hydroxide
ions into the wound exudate; (c) applying the wound dressing to the
wound; (d) contacting the second composition with the wound exudate
as the wound exudate passes through the dressing, thereby
dissolving the second composition and releasing hydrogen or
hydroxide ions into the wound exudate; and (e) contacting the first
composition with the wound exudate loaded with the released
hydrogen or hydroxide ions to cause the first composition to change
to the second colour and wherein the development of the second
colour indicates that the wound dressing is saturated at the
location of the second composition prior to its dissolution. The
methods further include the step of removing the dressing when the
second colour becomes visible.
[0042] In another aspect, methods are disclosed for monitoring
loading of a wound dressing by a wound exudate. The methods utilise
the dissolution of a soluble component provided at a location with
the wound dressing by the wound exudate to cause a component which
has a first state prior to contact with the wound exudate loaded
with the solubilised component to change to a second state upon
said contact, thereby indicating that the wound dressing in
saturated at the location of the soluble component.
[0043] In further aspects, methods are disclosed for monitoring
loading of a wound dressing by a wound exudate, the methods include
steps of: (a) providing a wound dressing containing a first
composition that can be solubilised into ions and a second
composition containing a pH indicator that indicates a pH change;
(b) flowing wound exudate into contact with the dressing to
solubilise the ions; and (c) contacting the second composition with
the solubilised ions until a pH is indicated.
SUMMARY SECTION 4
[0044] Section 4 of this application discloses devices and methods
related to wound dressings, having moisture indicators. The
mechanism of monitoring the moisture levels within the wound
dressing is dependent on the moisture indicator becoming exposed or
concealed to the user by a physical transformation of a part of the
dressing. This provides a visual indication of the dressing's
saturation and enables an assessment to be made as to whether the
dressing requires changing. Using a moisture indicator within the
dressing allows the status of the dressing to be assessed without
disturbing the wound and disrupting the healing process.
[0045] In one aspect, a wound dressing includes an absorbent layer
and a moisture indicator which indicates wound exudate loading
within the dressing, with the visibility of the moisture indicator
changing as a result of a physical transformation of a first
material within the dressing. In some embodiments, the physical
transformation of the first material of the dressing occurs when it
is directly contacted by wound exudate. In alternative embodiments,
the physical transformation of the first material of the dressing
occurs when a second material in the dressing is contacted by wound
exudate. For example, the second material may be the absorbent
layer. In some embodiments, the physical transformation is a change
in the appearance of the first material which causes at least a
part of the moisture indicator to become revealed or concealed to
the user. Such an alteration in the visibility of the moisture
indicator provides an indication of the level of saturation. In
certain embodiments, the physical transformation is, for example, a
transformation from a dry material to a wet material, from a solid
material to a gel or gel-like material and vice versa, or from a
substantially transparent/translucent material to substantially
opaque material and vice versa. In certain embodiments the
transformation is reversible. In some embodiments, the moisture
indicator is a coloured moisture indicator, a coloured substrate
and a water-soluble coloured dye. In some embodiments a plurality
of moisture indicators are distributed within the dressing, each
indicator being configured to indicate wound exudate loading within
a part of the dressing. In certain embodiments, each of the
plurality of indicators is a coloured moisture indicator having a
different colour, with the visibility of each colour indicating the
saturation of a different part of the dressing. In some
embodiments, the coloured moisture indicators can be used to
indicate the vertical and/or horizontal spread of wound exudate
throughout the dressing.
[0046] In another aspect, a wound dressing is disclosed which
includes at least a fluid outlet tube extending through at least a
portion of the dressing and a moisture indicator associated with
the fluid outlet tube, wherein the visibility of the moisture
indicator provides an indication of fluid leakage from the tube. In
certain embodiments the moisture indicator is wrapped around a
portion of the fluid outlet tube. In some embodiments the moisture
indicator is a water-soluble coloured dye bound to the fluid outlet
tube, and wherein the dye becomes visible if it is caused to
diffuse through the dressing as a result of fluid leakage from the
tube.
[0047] In another aspect, methods are disclosed for monitoring
saturation of a wound dressing by wound exudate, the methods
include (a) providing a wound dressing comprising an absorbent
element and a moisture indicator, wherein the visibility of the
indicator indicates wound exudate loading of the wound dressing;
(b) applying the wound dressing to a wound; and (c) monitoring the
visibility of the indicator. In some embodiments the moisture
indicator is a coloured layer that extends horizontally within the
dressing and the dressing includes a component that physically
transforms to alter the visibility of the coloured layer. In
certain implementations, the method includes the step of removing
the dressing when a pre-determined amount of the coloured layer
becomes visible. In alternative implementations, the method
includes the step of removing the dressing when a pre-determined
area of the coloured layer becomes invisible. In some embodiments,
the moisture indicator is a water-soluble coloured dye disposed
within the dressing. The methods further include the step of
removing the dressing when the coloured dye becomes visible as a
result of diffusion of the coloured dye.
SUMMARY SECTION 5
[0048] Disclose herein in section 5 of the application are systems,
devices, and methods for wound monitoring, and in particular for
monitoring wound pH levels to assess the efficacy and need for
intervention in wound treatment. The approaches described provide a
system and method for determining and monitoring changes in a wound
pH level and applying the wound pH information to determine any
needed changes in treatment. These systems and methods, when used
in combination with pH indicative wound dressings, can provide a
quick and accurate indication or assessment to a physician or a
patient of current wound status and treatment progression.
[0049] The embodiments described herein automate the calculation of
a pH value from a bandage color. This reduces the subjectivity of
the bandage reading and reduces the variance in readings that can
result from that subjectivity. After a physician, patient, or other
user takes a photo of the bandage, the image is processed to
determine the indicated pH using a computer-implemented process.
This process analyzes all users' images, thus reducing the
variation caused by color blindness or other differences in color
perception between individuals. The image processing can also
correct for lighting or image quality differences between readings,
thus improving accuracy compared to the subjective human
determinations. The image processing thus provides accurate and
reliable pH readings across a variety of conditions. Because the
bandage itself indicates the pH, these helpful readings can be
taken without moving the wound dressing. As a result, the risk of
infection and hampering wound healing is reduced compared to manual
inspections of the wound directly.
[0050] In one aspect, a method of monitoring a wound includes the
steps of capturing an image of a wound dressing with a user device
and then determining the color of a pH indicator on the wound
dressing by extracting RGB (Red, Green and Blue) values from the
captured image. A pH value is calculated for the wound dressing
from the dressing RGB values, and an indication of the calculated
pH value is displayed on the user device.
[0051] In some implementations, the method includes displaying a
guiding frame during image capture on the user device. The guiding
frame provides an indication of proper wound dressing alignment to
a user. The method also includes detecting the alignment of the
wound dressing relative to the displayed guide frame on the user
device, and the image may be automatically captured by the user
device when the wound dressing is properly aligned with the guiding
frame.
[0052] In certain implementations, the method also includes
rejecting an image having inadequate light or excessive shadow and
displaying on the user device a request to a user to capture a new
image. The method may also include displaying an option to accept
or reject the calculated pH value on the user device when the
calculated pH value is displayed.
[0053] In certain implementations, the method includes storing the
calculated pH value in a record of pH values in memory on the user
device. User input identifying a particular patient is received
with the user device and the stored record is associated with the
particular patient. In some embodiments, the user input includes a
selection of the particular patient from a list of stored patients,
while in other embodiments the user input includes identification
information for a new patient. The method also includes displaying
a trend of pH values for the particular patient on the user device,
where the displayed trend may include at least one of a graph and a
list of pH values.
[0054] In certain implementations, extracting dressing RGB values
from the captured image includes determining individual pixel RGB
values for each one of a plurality of pixels in the wound dressing
image and averaging the individual pixel RGB values for the
plurality of pixels to determine the dressing RGB values. Such
methods include defining a center point of the captured image and
defining a dressing circle region around the center point of the
image where the dressing circle region includes the plurality of
pixels for which the individual pixel RGB values are determined.
For example, the dressing circle region may have a radius between
about 5 and about 100 pixels, or between about 10 and about 50
pixels, or between about 20 and about 30 pixels.
[0055] In certain implementations, the method includes capturing an
image of a color calibration strip with the user device. The color
calibration strip may be captured in the same image as the wound
dressing or may be captured in a separate image. Such methods
include extracting calibration RGB values from the image of the
color calibration strip for each of a plurality of color blocks
that are included in the color calibration strip. Each color block
is associated with a standardized pH value, and the pH value for
the wound dressing is calculated using the dressing RGB values and
the calibration RGB values. Extracting calibration RGB values for
each of the plurality color blocks may include determining
individual pixel RGB values for each one of a plurality of pixels
in a color block and averaging the individual pixel RGB values for
the plurality of pixels in the color block to determine the
calibration RGB values for that color block. The methods may also
include defining a center point of each of the plurality of color
blocks which may be defined from alignment indicators positioned on
either side of the color calibration strip. A calibration circle
region is then defined around the center point of each color block
and the calibration circle regions include the plurality of pixels
for which the individual pixel RGB values are determined in each
color block. For example, each of the calibration circle regions
may have a radius between about 3 and about 10 pixels, or may have
a radius of about 5 pixels.
[0056] In certain implementations calculating a pH value for the
wound dressing includes calculating a distance between the dressing
RGB values and each of the calibration RGH values in a three
dimensional space. For example, the two smallest calculated
distances are determined and the pH value for the wound dressing is
calculated based on the RGB calibration values and standardized pH
values associated with the two smaller distances. The method may
also include normalizing the dressing RGB values to align defined
by the two RGB calibration values associated with the two shortest
distances and calculating the pH value for the wound dressing from
the normalized position of the dressing RGB values on the line.
[0057] In one aspect, a method of monitoring a wound includes
receiving an image of a wound dressing at a computing device, such
as a server, and determining the color of the pH indicator on the
wound dressing by extracting dressing RGB values from the received
image. The method includes calculating a pH value for the wound
dressing from the dressing RGB values and transmitting an
indication of a calculated pH value from the server.
[0058] In certain implementations, the method also includes
rejecting an image having an inadequate light or excessive shadow
at the server and transmitting a request from the server to a user
to capture a new image. The method may include displaying the
calculated pH value with an option to accept or reject the
calculated value on the user device.
[0059] In certain implementations, the method includes storing the
calculated pH value in a record of pH values in memory on the
server. User input identifying a particular patient is received and
the stored record is associated with the particular patient. The
user input may include a selection of the particular patient from a
list of stored patients or may include identification information
for a new patient. The method may include transmitting a trend of
pH values for the particular patient from the server for display on
a user device in communication with the server. The trend may
include at least one of a graph and a list of pH values.
[0060] In certain implementations, extracting dressing RGB values
from the received image includes determining individual pixel RGB
values for each one of a plurality of pixels in the image and
averaging the individual pixel RGB values for the plurality of
pixels to determine the dressing RGB values. In such a method a
center point of the received image is defined and a dressing circle
region is defined around the center point of the received image
where the dressing circle region includes the plurality of pixels
for which the individual pixel RGB values are determined. For
example, the dressing circle region may have a radius between about
5 and about 100 pixels, or between about 10 and about 50 pixels, or
between about 20 and about 30 pixels.
[0061] In certain implementations the method includes receiving an
image of a color calibration strip at a computing device, such as a
server. The color calibration strip may be received in the same
image as the wound dressing or may be received in a separate image.
The method includes extracting calibration RGB values from the
image of the color calibration strip for each of a plurality of
color blocks in the color calibration strip. Each color block is
associated with a standardized pH value and the pH value for the
wound dressing is calculated using the dressing RGB values and the
calibration RGB values. The extracting calibration RGB values for
each of the plurality of color blocks includes determining
individual pixel RGB values for each one of a plurality of pixels
in a color block and averaging the individual pixel RGB values for
the plurality of pixels in the color block to determine the
calibration RGB values for that color block. A center point of each
of the plurality of color blocks is defined and the center points
are defined from alignment indicators positioned on either side of
the color calibration strip. A calibration circle region may be
defined around the center point of each color block and the
calibration circle regions may include the plurality of pixels for
which the individual pixel RGB values are determined in each color
block. For example, the calibration circle regions may have a
radius between about 3 and about 10 pixels, or may have a radius of
about 5 pixels.
[0062] In certain implementations, the method includes calculating
a distance between the dressing RGB values and each of the
calibration RGB values in a three dimensional space. For example,
the two smallest calculated distances are determined and the pH
value for the wound dressing is calculated based on the RGB
calibration values and standardized pH values associated with the
two shortest distances. The method may also include normalizing the
dressing RGR values to a line defined by the two RG-B calibration
values associated with the two shortest distances and calculating
the pH value for the wound dressing from the normalized position of
the dressing RGB values on the line.
[0063] In one aspect, a method of monitoring a wound includes
capturing an image of a wound dressing having a pH indicator with a
user device, transmitting the captured image from the user device,
receiving a pH value at the user device for the wound dressing in
the captured image and displaying an indication of the received pH
value on the user device.
[0064] In certain implementations, the method includes displaying a
guiding frame on the user device during image capture, where the
guiding frame provides an indication of proper wound dressing
alignment to a user. The method may include detecting, with the
user device, the alignment of the wound dressing relative to the
displayed guide frame, and the image may be automatically captured
by the user device when the wound dressing is properly aligned with
the guiding frame. In certain implementations, the method includes
rejecting, with the user device, an image having inadequate light
or excessive shadow and displaying, on the user device, a request
to a user to capture a new image. In certain implementations, the
method includes displaying, on the user device, an option to accept
or reject the received pH value when the received pH value is
displayed.
[0065] In certain implementations, the method includes storing, in
memory on the user device, the received pH value in a record of pH
values. User input is received with the user device, and the user
input identifies a particular patient. The stored record is
associated with the particular patient. The user input may include
a selection of the particular patient from a list of stored
patients, or may include identification information for a new
patient. The method includes displaying, on the user device, a
trend of pH values for the particular patient, and the displayed
trend may include at least one of a graph and a list of pH
values.
[0066] In certain implementations, the method includes determining,
at a computing device, such as a server, in communication with the
user device, individual pixel RGB values for each one of a
plurality of pixels in the captured image; averaging, at the
server, the individual pixel RGB values for the plurality of pixels
to determine dressing RGB values; and calculating, at the server,
the pH value for the wound dressing from the dressing RGB values. A
center point of the captured image is defined, and a dressing
circle region is defined around the center point of the captured
image. The dressing circle region comprises the plurality of pixels
for which the individual pixel RGB values are determined. For
example, the dressing circle region may have a radius between about
5 and about 100 pixels, or between about 10 and about 50 pixels, or
between about 20 and about 30 pixels.
[0067] In certain implementations, the method includes capturing,
with the user device, an image of a color calibration strip. The
color calibration strip may be captured in the same image as the
wound dressing, or may be captured in a separate image. The method
includes extracting, at the server in communication with the user
device, calibration RGB values from the image of the color
calibration strip for each of a plurality of color blocks in the
color calibration strip. Each color block is associated with a
standardized pH value, and the pH value for the wound dressing is
calculated at the server using the calibration RGB values.
Extracting calibration RGB values for each of the plurality of
color blocks includes determining, at the server, individual pixel
RGB values for each one of a plurality of pixels in a color block
and averaging, at the server, the individual pixel RGB values for
the plurality of pixels in the color block to determine the
calibration RGB values for the color block. In certain
implementations, a center point is defined for each of the
plurality of color blocks, and the center points are defined from
alignment indicators positioned on either side of the color
calibration strip. A calibration circle region is defined around
the center point of each color block, wherein each of the
calibration circle regions comprises the plurality of pixels for
which the individual pixel RGB values are determined in each color
block. For example, each of the calibration circle regions may have
a radius between about 3 and about 10 pixels, or may have a radius
of about 5 pixels.
[0068] In certain implementations, the method includes calculating,
at the server, a distance between the dressing RGB values and each
of the calibration RGB values in a three-dimensional space. For
example, the method includes determining the two smallest
calculated distances and calculating the pH value for the wound
dressing based on the RGB calibration values and standardized pH
values associated with the two smallest distances. The method also
may include normalizing the dressing RGB values to a line defined
by the two RGB calibration values associated with the two shortest
distances and calculating the pH value for the wound dressing from
the normalized position of the dressing RGB values on the line.
[0069] In one aspect, a non-transitory computer-readable medium for
monitoring a wound is encoded with machine-readable instructions
for performing the methods described in any of the paragraphs of
Section 5 above.
[0070] In one aspect, a device for monitoring a wound includes
memory, a display, and processing circuitry in communication with
the memory and the display, the processing circuitry being
configured to perform any of the methods described in any of the
paragraphs of Section 5 above.
[0071] In one aspect, a computing device, such as a server, for
monitoring a wound includes memory, communications circuitry
coupled to a network for transmitting and receiving communications
over the network, and processing circuitry associated with the
communications circuitry and the memory, the processing circuitry
being configured to perform any of the methods described in any of
the paragraphs of Section 5 above.
[0072] In one aspect, a device for monitoring a wound includes
memory, communications circuitry coupled to a network for
transmitting and receiving communications over the network, and
processing circuitry associated with the communications circuitry
and the memory, the processing circuitry being configured to
perform any of the methods described in any of the paragraphs of
section 5 above.
[0073] In one aspect, a system for monitoring a wound includes a
computing device, such as server described in Section 5 above, and
the device described in Section 5 above.
[0074] In one aspect, a system for monitoring a wound includes
means for capturing an image of a wound dressing and means for
determining the color of a pH indicator on the wound dressing,
wherein the means for determining the color comprises means for
extracting RGB values from the captured image. The system also
includes means for calculating a pH value for the wound dressing
from the dressing RGB values and means for displaying an indication
of the calculated pH value.
[0075] In certain implementations, the system includes means for
displaying a guiding frame during image capture, wherein the
guiding frame provides an indication of proper wound dressing
alignment to a user. The system includes means for detecting the
alignment of the wound dressing relative to the displayed guide
frame, and the image is automatically captured by the means for
capturing when the wound dressing is properly aligned with the
guiding frame. The system may also include means for rejecting an
image having inadequate light or excessive shadow and means for
displaying a request to a user to capture a new image. The system
may also include means for displaying an option to accept or reject
the calculated pH value when the calculated pH value is
displayed.
[0076] In certain implementations, the system includes means for
storing the calculated pH value in a record of pH values. The
system includes means for receiving user input identifying a
particular patient, wherein the stored record is associated with
the particular patient. The user input may be a selection of the
particular patient from a list of stored patients, or may be
identification information for a new patient. The system includes
means for displaying a trend of pH values for the particular
patient, and the displayed trend comprises at least one of a graph
and a list of pH values.
[0077] In certain implementations, the means for extracting
dressing RGB values from the captured image comprises means for
determining individual pixel RGB values for each one of a plurality
of pixels in the image and means for averaging the individual pixel
RGH values for the plurality of pixels to determine the dressing
RGB values. The system includes means for defining a center point
of the captured image, and may include means fur defining a
dressing circle region around the center point of the captured
image, wherein the dressing circle region comprises the plurality
of pixels for which the individual pixel RGB values are determined.
For example, the dressing circle region may have a radius between
about 5 and about 100 pixels, or between about 10 and about 50
pixels, or between about 20 and about 30 pixels.
[0078] In certain implementations, the system includes means for
capturing an image of a color calibration strip. The color
calibration strip may be captured in the same image as the wound
dressing, or may be captured in a separate image. The system
includes means for extracting calibration RGB values from the image
of the color calibration strip for each of a plurality of color
blocks in the color calibration strip. Each color block is
associated with a standardized pH value, and the pH value for the
wound dressing is calculated using the dressing RGB values and the
calibration RGB values. The means for extracting calibration RGB
values for each of the plurality of color blocks comprises means
for determining individual pixel RGB values for each one of a
plurality of pixels in a color block and means for averaging the
individual pixel RGB values for the plurality of pixels in the
color block to determine the calibration RGB values for the color
block.
[0079] In certain implementations, the system includes means for
defining a center point of each of the plurality of color blocks,
and the center points are defined from alignment indicators
positioned on either side of the color calibration strip. The
system includes means for defining a calibration circle region
around the center point of each color block, wherein each of the
calibration circle regions comprises the plurality of pixels for
which the individual pixel RGB values are determined in each color
block. For example, each of the calibration circle regions may have
a radius between about 3 and about 10 pixels, or may have a radius
of about 5 pixels.
[0080] In certain implementations, the system includes means for
calculating a distance between the dressing RGB values and each of
the calibration RGB values in a three-dimensional space. For
example, the system includes means for determining the two smallest
calculated distances and means for calculating the pH value for the
wound dressing based on the RGB calibration values and standardized
pH values associated with the two smallest distances. The system
may also include means for normalizing the dressing RGR values to a
line defined by the two RGB calibration values associated with the
two shortest distances and means for calculating the pH value for
the wound dressing from the normalized position of the dressing RGB
values on the line.
[0081] In one aspect, a system for monitoring a wound includes
means for receiving an image of a wound dressing and means for
determining the color of a pH indicator on the wound dressing,
wherein the means for determining the color comprises means for
extracting dressing RGB values from the received image. The system
also includes means for calculating a pH value for the wound
dressing from the dressing RGB values and means for transmitting an
indication of the calculated pH value.
[0082] In certain implementations, the system includes means for
rejecting an image having inadequate light or excessive shadow and
means for transmitting a request to a user to capture a new image.
The system has means for displaying the calculated pH value with an
option to accept or reject the calculated pH value.
[0083] In certain implementations, the system includes means for
storing the calculated pH value in a record of pH values. Means for
receiving user input identifying a particular patient is provided,
wherein the stored record is associated with the particular
patient. The user input may include a selection of the particular
patient from a list of stored patients, or may include
identification information for a new patient. The system includes
means for transmitting a trend of pH values for the particular
patient for display on a user device in communication with the
means for transmitting, and the trend comprises at least one of a
graph and a list of pH values.
[0084] In certain implementations, the means for extracting
dressing RGB values from the received image comprises means for
determining individual pixel RGB values for each one of a plurality
of pixels in the image and means for averaging the individual pixel
RGH values for the plurality of pixels to determine the dressing
RGB values. The system includes means for defining a center point
of the received image and means for defining a dressing circle
region around the center point of the received image, wherein the
dressing circle region comprises the plurality of pixels for which
the individual pixel RGB values are determined. For example, the
dressing circle region may have a radius between about 5 and about
100 pixels, or between about 10 and about 50 pixels, or between
about 20 and about 30 pixels.
[0085] In certain implementations, the system includes means for
receiving an image of a color calibration strip. The color
calibration strip may be in the same received image as the wound
dressing, or may be in a separate image. The system includes means
for extracting calibration RGB values from the image of the color
calibration strip for each of a plurality of color blocks in the
color calibration strip. Each color block is associated with a
standardized pH value, and the pH value for the wound dressing is
calculated using the dressing RGB values and the calibration RGB
values. The means for extracting calibration RGB values for each of
the plurality of color blocks comprises means for determining
individual pixel RGB values for each one of a plurality of pixels
in a color block and means for averaging the individual pixel RGB
values for the plurality of pixels in the color block to determine
the calibration RGB values for the color block.
[0086] In certain implementations, the system includes means for
defining a center point of each of the plurality of color blocks.
The center points are defined from alignment indicators positioned
on either side of the color calibration strip. The system includes
means for defining a calibration circle region around the center
point of each color block, wherein each of the calibration circle
regions comprises the plurality of pixels for which the individual
pixel RGB values are determined in each color block. For example,
each of the calibration circle regions may have a radius between
about 3 and about 10 pixels, or may have a radius of about 5
pixels.
[0087] In certain implementations, the system includes means for
calculating a distance between the dressing RGB values and each of
the calibration RGB values in a three-dimensional space. For
example, the system includes means for determining the two smallest
calculated distances and means for calculating the pH value for the
wound dressing based on the RGB calibration values and standardized
pH values associated with the two smallest distances. The system
may also include means for normalizing the dressing RGB values to a
line defined by the two RGB calibration values associated with the
two shortest distances and means for calculating the pH value for
the wound dressing from the normalized position of the dressing RGB
values on the line.
[0088] In one aspect, a system for monitoring a wound includes
means for capturing an image of a wound dressing having a pH
indicator, means for transmitting the captured image, means for
receiving a pH value for the wound dressing in the captured image,
and means for displaying an indication of the received pH
value.
[0089] In certain implementations, the system includes means for
displaying a guiding frame during image capture, wherein the
guiding frame provides an indication of proper wound dressing
alignment to a user. The system may also include means for
detecting the alignment of the wound dressing relative to the
displayed guide frame, wherein the image is automatically captured
by the means for capturing when the wound dressing is properly
aligned with the guiding frame. The system may include means for
rejecting an image having inadequate light or excessive shadow and
means for displaying a request to a user to capture a new image.
The system may also include means for displaying an option to
accept or reject the received pH value when the received pH value
is displayed.
[0090] In certain implementations, the system includes means for
storing the received pH value in a record of pH values. User input
identifying a particular patient is received, and the stored record
is associated with the particular patient. The user input may
include a selection of the particular patient from a list of stored
patients or may include identification information for a new
patient. The system includes means for displaying a trend of pH
values for the particular patient, and trend comprises at least one
of a graph and a list of pH values.
[0091] In certain implementations, the system includes means for
determining individual pixel RGB values for each one of a plurality
of pixels in the captured image, means for averaging the individual
pixel RGB values for the plurality of pixels to determine dressing
RGB values, and means for calculating the pH value for the wound
dressing from the dressing RGB values. The system includes means
for defining a center point of the captured image and means for
defining a dressing circle region around the center point of the
captured image, wherein the dressing circle region comprises the
plurality of pixels for which the individual pixel RGB values are
determined. For example, the dressing circle region may have a
radius between about 5 and about 100 pixels, or between about 10
and about 50 pixels, or between about 20 and about 30 pixels.
[0092] In certain implementations, the system includes means for
capturing an image of a color calibration strip. The color
calibration strip may be captured in the same image as the wound
dressing, or may be captured in a separate image. The system
includes means for extracting calibration RGB values from the image
of the color calibration strip for each of a plurality of color
blocks in the color calibration strip. Each color block is
associated with a standardized pH value, and the pH value for the
wound dressing is calculated using the calibration RGB values. The
means for extracting calibration RGB values for each of the
plurality of color blocks comprises means for determining
individual pixel RGB values for each one of a plurality of pixels
in a color block and means for averaging the individual pixel RGB
values for the plurality of pixels in the color block to determine
the calibration RGB values for the color block.
[0093] In certain implementations, the system includes means for
defining a center point of each of the plurality of color blocks,
and the center points are defined from alignment indicators
positioned on either side of the color calibration strip. The
system includes means for defining a calibration circle region
around the center point of each color block, wherein each of the
calibration circle regions comprises the plurality of pixels for
which the individual pixel RGB values arc determined in each color
block. For example, each of the calibration circle regions may have
a radius between about 3 and about 10 pixels, or may have a radius
of about 5 pixels.
[0094] In certain implementations, the system includes means for
calculating a distance between the dressing RGB values and each of
the calibration RGB values in a three-dimensional space. For
example, the system includes means for determining the two smallest
calculated distances and means for calculating the pH value for the
wound dressing based on the RGB calibration values and standardized
pH values associated with the two smallest distances. The system
may also include means for normalizing the dressing RGB values to a
line defined by the two RGB calibration values associated with the
two shortest distances and means for calculating the pH value for
the wound dressing from the normalized position of the dressing RGB
values on the line.
[0095] In one aspect, a system for monitoring a wound includes a
system described above.
[0096] Variations and modifications of these embodiments will occur
to those of skill in the art after reviewing this disclosure. The
foregoing features and aspects may be implemented, in any
combination and sub-combinations (including multiple dependent
combinations and sub-combinations), with one or more other features
described herein. The various features described or illustrated
above, including any components thereof, may be combined or
integrated in other systems. Moreover, certain features may be
omitted or not implemented.
[0097] Further areas of applicability of the disclosed devices and
methods will become apparent from the detailed description provided
hereinafter. It should be understood that the detailed description
and specific examples, while indicating particular embodiments, are
intended for purposes of illustration only and are not intended to
limit the scope of the. Disclosure or any of the claims that may be
pursued.
DESCRIPTION OF THE DRAWINGS SECTION 1
[0098] The foregoing and other objects and advantages will be
appreciated more fully upon consideration of the following detailed
description, taken in conjunction with the accompanying drawings,
in which like reference numbers refer to like parts throughout.
These depicted embodiments are to be understood as illustrative and
not limiting in any way:
[0099] FIGS. 1A and 1B are side cross-sectional views of an
illustrative device having a pH indicator, the colour of which
changes as a result of alterations in the pH of a fluid.
[0100] FIGS. 2A and 2B are side cross-sectional views of an
illustrative device in which a fluid is guided via a conduit to a
pH indication zone which includes a pH indicator, the colour of the
indicator changes as an indication of the pH of the fluid.
[0101] FIG. 3 is a photograph of a Post-Op sample dyed with
GJM-514, illustrating changes in colour of the dye in response to
solution changing pH along a pH unit interval scale.
[0102] FIGS. 4A-F are graphic representations of colour pen
measurements for the Post-Op sample illustrated in FIG. 3.
[0103] FIG. 5 is a photograph of a Post-Op sample dyed with a
first-combination of dyes, illustrating changes in colour of the
dye combination in response to a solution changing pH along a pH
unit interval scale.
[0104] FIGS. 6A-D are graphic representations of colour pen
measurements for the Post-Op sample illustrated in FIG. 5.
[0105] FIG. 7 is a photograph of a Post-Op sample dyed with a
second combination of dyes, illustrating changes in colour of the
dye combination in response to a buffered solution changing pH
along a pH unit interval scale.
[0106] FIGS. 8A-E are graphic representations of the colour pen
measurements for the Post-Op sample illustrated in FIG. 7.
[0107] FIG. 9 is a photograph of a Post-Op sample dyed with a third
combination of dyes, illustrating changes in colour of the dye
combination in response to a buffered solution changing pH along a
pH unit interval scale.
[0108] FIGS. 10A-F are graphic representations of the colour pen
measurements for the Post-Op sample illustrated in FIG. 9.
[0109] FIG. 11 is a photograph of a Post-Op sample dyed with a
fourth combination of dyes, illustrating changes in colour of the
dye combination in response to a buffered solution changing pH
along a pH unit interval scale.
[0110] FIGS. 12A-E are graphic representations of the colour pen
measurements for the Post-Op sample illustrated in FIG. 11.
[0111] FIGS. 13A-F are photographs of pH sensitive gauze in ex-vivo
wound model with alternating pH 5 and pH 8 horse serum being pumped
in.
[0112] FIG. 13A is a photograph of pH 5 after 2.5 hours approx.
[0113] FIG. 13B is a photograph of pH 5 after 5.5 hours approx.
[0114] FIG. 13C is a photograph of pH 8 after 8 hours approx.
[0115] FIG. 13D is a photograph of pH 5 after 3.5 hours approx.
[0116] FIG. 13E is a photograph of pH 5 after 5.5 hours approx.
with the flow rate of horse serum increased at 3.5 hours.
[0117] FIG. 13F is a photograph of pH 5 after 7.5 hours with the
flow rate of horse serum increased at 3.5 hours and at 5.5
hours.
[0118] FIGS. 14A to F are photographs of pH sensitive foam (V.A.C.
White Foam trade mark of KCT) in an ex-vivo wound model with
alternating pH5 and pH 8 horse serum being pumped in.
[0119] FIG. 14A is a photograph at pH 5 after 2.5 hours approx.
[0120] FIG. 14B is a photograph at pH 5 after 5.5 hours approx.
[0121] FIG. 14C is a photograph at pH 8 after 15 hours approx.
[0122] FIG. 14D is a photograph at pH 5 after 3.5 hours approx.
[0123] FIG. 14E is a photograph at pH 5 after 5.5 hours approx.,
with the flow rate of horse scrum increased at 3.5 hours.
[0124] FIG. 14F is a photograph at pH 5 after 7.5 hours approx.,
with the flow rate of horse serum increased at 3.5 hours and at 5.5
hours.
[0125] FIGS. 15A to F are photographs of pH sensitive gauze in an
ex-vivo wound model with alternating basic and acidic water being
pumped in.
[0126] FIG. 15A is a photograph at 8 am Day 1 showing basic pH.
[0127] FIG. 15B is a photograph at 12:57 pm Day 1 (5 hours) showing
basic pH.
[0128] FIG. 15C is a photograph at 08:03 am Day 2 (24 hours)
showing basic pH.
[0129] FIG. 15D is a photograph at 12:41 pm Day 2 (5 hours) showing
acidic pH.
[0130] FIG. 15E is a photograph at 15:06 Day 2 (7 hours) showing
acidic pH.
[0131] FIG. 15F is a photograph at 16:47 Day 2 (9 hours) showing
acidic pH.
[0132] FIGS. 16A to F are photographs of pH sensitive foam in an
ex-vivo wound model with alternating basic and acidic water being
pumped in.
[0133] FIG. 16A is a photograph at 8 am Day 1 showing basic pH.
[0134] FIG. 16B is a photograph at 12:57 pm Day 1 (5 hours) showing
basic pH.
[0135] FIG. 16C is a photograph at 08:03 am Day 2 (24 hours)
showing basic pH.
[0136] FIG. 16D is a photograph at 09:06 Day 2 (1 hour) showing
acidic pH.
[0137] FIG. 16E is a photograph at 15:06 Day 2 (7 hours) showing
acidic pH.
[0138] FIG. 16F is a photograph at 16:47 Day 2 (9 hours) showing
acidic pH.
[0139] FIGS. 17A to H are photographs of pH sensitive foam in a
clear Perspex wound model with alternating basic and acidic
water.
[0140] FIG. 17A is a photograph at 8 am Day 1 showing basic pH.
[0141] FIG. 17B is a photograph at 12:56 Day 1 (5 hours) showing
basic pH.
[0142] FIG. 17C is a photograph at 16:20 Day 1 (8.5 hours) showing
basic pH.
[0143] FIG. 17D is a photograph at 8:02 am Day 2 (24 hours) showing
basic pH.
[0144] FIG. 17E is a photograph at 09:05 am Day 2 (1 hour) showing
acidic pH.
[0145] FIG. 17F is a photograph at 10:50 am Day 2 (3 hours) showing
acidic pH.
[0146] FIG. 17G is a photograph at 13:26 Day 2 (5.5 hours) showing
acidic pH.
[0147] FIG. 17H is a photograph at 15:05 Day 2 (7 hours) showing
acidic pH.
[0148] FIG. 18 illustrates an embodiment of a negative pressure
system.
[0149] FIG. 19 is a schematic illustration of a system for the
treatment of abdominal wounds.
[0150] FIG. 20 illustrates an embodiment of a wound treatment
system.
[0151] FIGS. 21A-D illustrate the use and application of an
embodiment of a wound treatment system onto a patient which may be
used with any dressing embodiment disclosed wherein.
[0152] FIG. 22 illustrates an embodiment of a negative pressure
wound treatment system employing a wound dressing capable of
absorbing and storing wound exudate and a flexible suction
adapter.
[0153] FIG. 23 illustrates another embodiment of a wound dressing
in cross-section.
[0154] FIG. 24 illustrates an exploded view of another embodiment
of a wound dressing.
[0155] FIGS. 25A and 25B are side cross-sectional views of an
illustrative device having a pH indicator, the colour of which
changes as a result of alterations in the pH of the wound
exudate.
[0156] FIGS. 26A-D illustrate side cross-sectional views of an
illustrative wound dressing having a device shown in FIGS. 25A and
25B applied to is wound-facing surface.
[0157] FIGS. 27A and 27B are side cross-sectional views of an
illustrative wound dressing in which wound exudate is guided via a
conduit to a pH indication zone which includes a pH indicator, the
colour of the indicator changes as a result of alterations in the
pH of the wound exudate.
[0158] FIGS. 28A and 28B are side cross-sectional views of an
illustrative device in which the colour of a pH indicator changes
from a first colour to a second colour.
[0159] FIGS. 29A and 29B are side cross-sectional views of the
device illustrated in FIGS. 28A and 28B having a spacer layer to
physically separate a soluble composition and a pH indicator.
[0160] FIGS. 30A and 30B are side cross-sectional views of an
illustrative device, in which a soluble composition is encapsulated
with a soluble barrier.
[0161] FIGS. 31A and 31B are side cross-sectional views of an
illustrative combination of a wound dressing and a device as
disclosed herein.
[0162] FIGS. 32A and 32B are plan views of an illustrative
combination of a wound dressing and a device as disclosed
herein.
[0163] FIGS. 33A and 33B are side cross-sectional views of an
illustrative wound dressing having a moisture indicator, the
visibility of which alters as a result of a physical transformation
of a first material of the dressing.
[0164] FIGS. 34A and 34B are side cross-sectional and plan views of
an illustrative wound dressing in which a water-soluble coloured
moisture indicator becomes visible as the dressing becomes
saturated.
[0165] FIGS. 35A and 35B are side cross-sectional and plan views of
an illustrative wound dressing in which a coloured moisture
indicator becomes invisible as a result of the physical
transformation of a first material from transparent to opaque.
[0166] FIGS. 36A and 36B are side cross-sectional and plan views of
an illustrative wound dressing in which a coloured moisture
indicator becomes visible as a result of the physical
transformation of a first material from opaque to transparent.
[0167] FIGS. 37A and 37B are side cross-sectional and plan views of
a plan view of an illustrative wound dressing in which a coloured
moisture indicator is associated with multiple layers of the
dressing and becomes visible as a result of the physical
transformation of a first material associated with each layer.
[0168] FIG. 38 shows a flow chart for a method of monitoring wound
pH levels according to some implementations.
[0169] FIG. 39 shows a flow chart for a method of processing a
wound dressing image and calculating a pH level based on the color
of the image according to some implementations.
[0170] FIG. 40 shows a visual representation of a pH calculation
process according to some implementations.
[0171] FIG. 41 shows an illustrative pH-sensitive wound dressing
according to some implementations.
[0172] FIG. 42 shows an illustrative system including a user
device, a server, and a communications network according to some
implementations.
[0173] FIG. 43 shows an illustrative user device according to some
implementations.
[0174] FIG. 44 shows an illustrative computing device according to
some implementations.
[0175] FIGS. 45-50 show illustrative user device screenshots
according to some implementations.
DETAILED DESCRIPTION SECTION 1
[0176] To provide an understanding of the devices and methods
describe herein, certain illustrative embodiments and examples will
now be described.
[0177] Reference numbers cited in Section 1 correspond to the
reference numbers used in FIGS. 1-17.
[0178] FIG. 1A depicts a device 100 having a fluid-contacting
surface 102 and an opposing non-fluid-contacting surface 104. FIG.
1B depicts the device 100 being brought into contact with a fluid
106. The device 100 can be made of any material that is suitable
for contact with the fluid without disintegrating.
[0179] The device further includes a pH indicator 108 which is
applied to one or both of surfaces 102 and/or 104. The pH indicator
is covalently immobilised on or adjacent to the surface 102 and/or
104 so that it is not washed away by the fluid.
[0180] In embodiments, the pH indicator is chemically bound to the
surface 102 and/or 104. For example, the pH indicator is covalently
bound directly to the surface 102 and/or 104. In alternative
embodiments, the surface 102 and/or 104 is provided within an
adhesive and the pH indicator is covalently bound to reactive
moieties within the adhesive. For example, a conventional acrylic
adhesive, such as K5 (Smith & Nephew, Inc) used in the
construction of wound dressings contains residues of
2-hydroxy-ethylmethacrylate, which provide a reactive functional
hydroxyl (OH) group, pendant to the polymer backbone, to which the
pH indicator can be covalently bound. Other suitable adhesives
include acrylic-based adhesives with pendant OH or COOR groups.
[0181] In embodiments on which the pH indicator is only applied to
one surface of a non-porous device, then an indication, for
indicating which side the pH indicator is applied to may be
provided. This indication allows the user to appropriately orient
the device during placement on or in the fluid to ensure that the
surface which has the pH indicator is correctly orientated and
comes into contact with the fluid.
[0182] The pH indicator may be applied across substantially the
entire surface 102 and/or 104, to allow any variations in the pH at
the meniscus of the fluid sample to be identified. Alternatively,
the pH indicator may be applied to discrete areas of surfaces 102
and/or 104. The pH indicator exhibits a first colour prior to
contact with a fluid and changes colour as a function of the pH of
the fluid. The first colour of the pH indicator may be
colourless.
[0183] The pH indicator is capable of reversibly changing colour in
response to pH. In embodiments, the pH indicator is a phenylazo
compound. In certain embodiments, the phenylazo compound is
selected from the group listed in Table 1. In some embodiments, the
phenylazo compound is not
2-[4(2-hydroxycthylsulfonyl)-phenyl]diazenyl]-4-methylphenol. In
some embodiments, the phenylazo compound is not
hydroxy-4-[4[(hydroxyethylsulphonyl)-phenylazo]-napthalene-2-sulphonate.
In some embodiments, the phenylazo compound is not
2-fluoro-4-[4[(2-hydroxyethanesulphonyl)-phenylazo]-6-methoxy
phenol. In some embodiments, the phenylazo compound is not
4-[4-(2-hydroxyethylsulphonyl)-phenylazo]-2,6-dimethoxyphenol. In
certain embodiments, the phenylazo compound is
2-[4(2-hydroxyethylsulfonyl)-phenyl]diazenyl]-4-methylphenol. In
some embodiments, the pH indicator includes a plurality of
phenylazo compounds. In some embodiments, the pH indicator includes
a combination of phenylazo compounds, for example a combination of
phenylazo compounds selected from the group listed in Table 1. In
some embodiments, the pH indicator includes a combination of two
phenylazo compounds. In some embodiments, the pH indicator includes
a combination of three phenylazo compounds. In some embodiments,
2-[4(2-hydroxyethylsulfonyl)-phenyl]diazenyl]-4-methylphenol is
combined with at least one other phenylazo compound selected from
the group listed in Table 1. The ratio of phenylazo compound may be
1:1, but other ratios are envisaged, for example, but in no way
limiting, 0.5:1.5 or 1.5:0.5 or 1:2 or 2:1 or 1:0.1. In alternative
embodiments, the pH indicator includes at least one phenylazo
compound, for example a phenylazo compound selected from the group
listed in Table 1 and at least one other compound that is not a
phenylazo compound. In certain embodiments, the pH indicator is not
a phenylazo compound.
[0184] FIGS. 2 A&B illustrate a device in which temporal
changes in pH can be monitored whilst the device is in situ. FIG.
2A shows a side cross-sectional view of a device 200 comprising an
absorbent element 204, the lower surface of which is a
fluid-contacting surface 206. The device also comprises a pH
indication zone 208 which is located at or adjacent to the opposing
non fluid-contacting surface 210. This pH indication zone includes
a, pH indicator (e.g., as disclosed herein) which is capable of
reversibly changing colour in response to changes in pH. In this
illustrated embodiment, the pH indication zone 208 is disposed
above the absorbent layer 204, so the pH indicator can be monitored
over time without having to remove the device from any substrate
that it is adhered to.
[0185] A transparent layer 212 overlays at least part of the pH
indication zone, which protects the integrity of the pH indicator
but still allows the user to monitor the colour of the pH indicator
over time. The device includes at least one conduit that is
configured to direct fluid to the pH indication zone 206, ensuring
that the pH of the fluid is not materially altered as it passes
through the components of the device. One or a plurality of
conduits could be used. As shown in FIGS. 2 A&B, two conduits
are used, although one or more other conduits could also be
included. The two conduits 214 and 216 are oriented vertically and
extend across the device.
[0186] The conduits are preferably sealed, so as to not exchange
fluid with the absorbent layer, but are in communication with the
pH indication zone 208 and direct the fluid to the pH indication
zone 208 located in the upper part of the device. The conduits may
be in the form of narrow capillaries which transmit the fluid
towards the pH indication zone 208. The conduits may incorporate or
may be formed from wicking materials, for example, woven,
non-woven, knitted, tows or fibres made of suitable materials to
facilitate wicking of the fluid towards the pH indication zone 208.
In alternative embodiments, a pH indication zone is provided at or
near a lateral edge 218 or 220 of the device and at least one
conduit is provided within the device to direct the fluid laterally
to the pH indication zone. In some embodiments, the pH indication
zone is provided in a layer of the device which forms an outer
surface of the device and a transparent cover layer is not used. In
some embodiments, the conduits may take the foml of a long strip or
be of an elongated lozenge shape when viewed from the
fluid-contacting surface. Alternatively, the conduit may be formed
of crosses or quadrilateral shapes.
[0187] Methods of immobilising a phenylazo dye on the devices
illustrated in FIGS. 1 and 2 are also contemplated. An example
includes the following steps:
[0188] In a first step, 25 mg of a phenylazo pH indicating dye, for
example a phenylazo pH indicating dye selected from the group
listed in Table 1, is reacted with 140 .mu.l concentrated sulphuric
acid for 30 mins to form a dye solution.
[0189] In a second step, 200 ml of distilled water is added to the
dye solution formed in the first step.
[0190] In a third step, 406 .mu.l of a 32% w/v solution of sodium
hydroxide is added to the solution formed in the second step.
[0191] In a fourth step, 25.45 ml of a 2.36M solution of sodium
carbonate is added to the solution formed in the third step.
[0192] In a fifth step, 1.35 ml of a 32% w/v solution of sodium
hydroxide is added to the solution formed in the fourth step and
the volume made up to 250 ml with distilled water.
[0193] In a sixth step, a material on which the pH indicating dye
is to be bound is placed in the solution and left to react for
approximately 1-2 hours. Examples of suitable materials include,
but are not limited to: TENCEL fibres of the Durafiber product,
polyurethane foam of the Allevyn product, cellulose pad of the
Opsite Post-op product, or KS adhesive-coated polyurethane film,
all available from Smith & Nephew, Inc. The material is then
washed with distilled water until no dye is released. The material
is then dried.
DETAILED DESCRIPTION SECTION 2
[0194] To provide an understanding of the devices and methods
describe herein, certain illustrative embodiments and examples will
now be described.
[0195] Reference numbers cited in Section 2 correspond to the
reference numbers used in FIGS. 18-27.
[0196] Embodiments disclosed herein relate to apparatuses and
methods to treat and/or evaluate a wound, including pump
components, wound dressing components, and apparatuses that
incorporate one or more pH indicators and may be used to apply
negative pressure wound therapy. The apparatuses and components
comprising the wound overlay and packing materials, if any, are
sometimes collectively referred to herein as dressings.
[0197] It will be appreciated that throughout this specification
reference is made to a wound. It is to be understood that the term
wound is to be broadly construed and encompasses open and closed
wounds in which skin is tom, cut or punctured or where trauma
causes a contusion, or any other superficial or other conditions or
imperfections on the skin of a patient or otherwise that benefit
from reduced pressure treatment. A wound is thus broadly defined as
any damaged region of tissue where fluid may or may not be
produced. Examples of such wounds include, but are not limited to,
abdominal wounds or other large or incisional wounds, either as a
result of surgery, trauma, stemiotomies, fasciotomies, or other
conditions, dehisced wounds, acute wounds, chronic wounds, subacute
and dehisced wounds, traumatic wounds, flaps and skin grafts,
lacerations, abrasions, contusions, bums, diabetic ulcers, pressure
ulcers, stoma, surgical wounds, trauma and venous ulcers or the
like.
[0198] Some of the wound dressings described herein may be used as
part of a negative pressure or reduced pressure system. As is used
herein, reduced or negative pressure levels, such as -X mmHg,
represent pressure levels that are below standard atmospheric
pressure, which corresponds to 760 mmHg (or 1 atm, 29.93 in Hg,
101.325 kPa, 14.696 psi, etc.). Accordingly, a negative pressure
value of -X mmHg reflects absolute pressure that is X mmHg below
760 mmHg or, in other words, an absolute pressure of (760-X) mmHg.
In addition, negative pressure that is "less" or "smaller" than X
mmHg corresponds to pressure that is closer to atmospheric pressure
(e.g., -40 mmHg is less than -60 mmHg). Negative pressure that is
"more" or "greater" than -X mmHg corresponds to pressure that is
further from atmospheric pressure (e.g., -80 mmHg is more than -60
mmHg).
[0199] The negative pressure range for some embodiments of the
present disclosure can be approximately -80 mmHg, or between about
-20 mmHg and -200 mmHg. Note that these pressures arc relative to
normal ambient atmospheric pressure. Thus, -200 mmHg would be about
560 mmHg in practical terms. In some embodiments, the pressure
range can be between about -40 mmHg and -150 mmHg. Alternatively a
pressure range of up to -75 mmHg, up to -80 mmHg or over -80 mmHg
can be used. Also in other embodiments a pressure range of below
-75 mmHg can be used. Alternatively, a pressure range of over
approximately -100 mmHg, or even -150 mmHg, can be supplied by the
negative pressure apparatus. In some embodiments, negative pressure
may be varied over time for example using a sinusoidal wave, square
wave, and/or in synchronization with one or more patient
physiological indices (e.g., heartbeat). Examples of such
applications where additional disclosure relating to the preceding
may be found include application Ser. No. 11/919,355, titled "Wound
treatment apparatus and method," filed Oct. 26, 2007, published as
US 2009/0306609; and U.S. Pat. No. 7,753,894, titled "Wound
cleansing apparatus with stress," issued Jul. 13, 2010. Both
applications are hereby incorporated by reference in their
entirety. Other applications that may contain teachings relevant
for use with the embodiments described herein may include
application Ser. No. 12/886,088, titled "Systems And Methods For
Using Negative Pressure Wound Therapy To Manage Open Abdominal
Wounds," filed Sep. 20, 2010, published as US 2011/0213287;
application Ser. No. 13/092,042, titled "Wound Dressing And Method
Of Use," filed Apr. 21, 2011, published as US 2011/0282309.
[0200] FIG. 18 illustrates an embodiment of a negative pressure
treatment system 100 that comprises a wound packer 102 inserted
into a wound 101. The wound packer 102 may comprise porous
materials such as foam, and in some embodiments may comprise one or
more embodiments of wound closure devices described in further
detail herein. In some embodiments, the perimeter or top of any
wound closure device inserted into the wound 101 may also be
covered with foam or other porous materials. A drape 104 may be
placed over the wound 101, and is preferably adhered or sealed to
the skin on the periphery of the wound 101 so as to create a
fluid-tight seal. An aperture 106 may be made through the drape
104--which can be manually made or preformed into the drape 104--so
as to provide a fluidic connection from the wound 101 to a source
of negative pressure such as a pump 110. Preferably, the fluidic
connection between the aperture 106 and the pump 110 is made via a
conduit 108. In some embodiments, the conduit 108 may comprise a
RENASYS.RTM. Soft Port.TM., manufactured by Smith & Nephew. Of
course, in some embodiments, the drape 104 may not necessarily
comprise an aperture 106, and the fluidic connection to the pump
110 may be made by placing the conduit 108 below the drape. In some
wounds, particularly larger wounds, multiple conduits 108 may be
used, fluidically connected via one or more apertures 106.
[0201] In some embodiments, the drape 104 may be provided with one
or more corrugations or folds. Preferably, the corrugations are
aligned along the longitudinal axis of the wound, and as such may
support closure of the wound by preferentially collapsing in a
direction perpendicular to the longitudinal axis of the wound. Such
corrugations may aid in the application of contractile forces
parallel to the wound surface and in the direction of wound
closure. Examples of such drapes may be found in application Ser.
No. 12/922,118, titled "Vacuum Closure Device," filed Nov. 17, 2010
(published as US 2011/0054365), which is hereby incorporated by
reference in its entirety.
[0202] In use, the wound 101 is prepared and cleaned. In some
cases, such as abdominal wounds, a non- or minimally-adherent organ
protection layer (not illustrated) may be applied over any exposed
viscera. The wound packer 102 is then inserted into the wound, and
is covered with the drape 104 so as to form a fluid-tight seal. A
first end of the conduit 108 is then placed in fluidic
communication with the wound, for example via the aperture 106. The
second end of the conduit 108 is connected to the pump 110. The
pump 110 may then be activated so as to supply negative pressure to
the wound 101 and evacuate wound exudate from the wound 101. As
will be described in additional detail below and in relation to the
embodiments of the foregoing wound closure devices, negative
pressure may also aid in promoting closure of the wound 101, for
example by approximating opposing wound margins. In certain
embodiments, a pH indicator dye, as will be described in more
detail later in the specification, may be incorporated into the
wound filler to visually indicate the pH of the wound.
[0203] Turning to FIG. 19, treatment of a wound with negative
pressure in certain embodiments uses a negative pressure treatment
system 501 as illustrated schematically here. In this embodiment, a
wound site 510, illustrated here as an abdominal wound site, may
benefit from treatment with negative pressure. Such abdominal wound
sites may be a result of, for example, an accident or due to
surgical intervention. In some cases, medical conditions such as
abdominal compartment syndrome, abdominal hypertension, sepsis, or
fluid edema may require decompression of the abdomen with a
surgical incision through the abdominal wall to expose the
peritoneal space, after which the opening may need to be maintained
in an open, accessible state until the condition resolves. Other
conditions may also necessitate that an opening-particularly in the
abdominal cavity-remain open, for example if multiple surgical
procedures are required (possibly incidental to trauma), or there
is evidence of clinical conditions such as peritonitis or
necrotizing fasciitis.
[0204] In cases where there is a wound, particularly in the
abdomen, management of possible complications relating to the
exposure of organs and the peritoneal space is desired, whether or
not the wound is to remain open or if it will be closed. Therapy,
preferably using the application of negative pressure, can be
targeted to minimize the risk of infection, while promoting tissue
viability and the removal of deleterious substances from the wound
site. The application of reduced or negative pressure to a wound
site has been found to generally promote faster healing, increased
blood flow, decreased bacterial burden, increased rate of
granulation tissue formation, to stimulate the proliferation of
fibroblasts, stimulate the proliferation of endothelial cells,
close chronic open wounds, inhibit bum penetration, and/or enhance
flap and graft attachment, among other things. It has also been
reported that wounds that have exhibited positive response to
treatment by the application of negative pressure include infected
open wounds, decubitus ulcers, dehisced incisions, partial
thickness bums, and various lesions to which flaps or grafts have
been attached. Consequently, the application of negative pressure
to a wound site 510 can be beneficial to a patient.
[0205] Accordingly, certain embodiments provide for a wound contact
layer 105 to be placed over the wound site 510. Preferably, the
wound contact layer 105 can be a thin, flexible material which will
not adhere to the wound site or the exposed viscera in close
proximity. For example, polymers such as polyurethane,
polyethylene, polytetrafluoroethylene, or blends thereof may be
used. In one embodiment, the wound contact layer is permeable. For
example, the wound contact layer 105 can be provided with openings,
such as holes, slits, or channels, to allow the removal of fluids
from the wound site 510 or the transmittal of negative pressure to
the wound site 510. Additional embodiments of the wound contact
layer 105 arc described in further detail below. In certain
embodiments, a pH indicator dye, as will be described in more
detail later in the specification, may be incorporated into the
wound contact layer to visually indicate the pH of the wound.
[0206] Certain embodiments of the negative pressure treatment
system 101 may also use a porous pad 103, which can be disposed
over the wound contact layer 105. This pad 103 can be constructed
from a porous material, for example foam, that is soft, resiliently
flexible, and generally conformable to the wound site 510. Such a
foam can include an open-celled and reticulated foam made, for
example, of a polymer. Suitable foams include foams composed of,
for example, polyurethane, silicone, and polyvinyl alcohol.
Preferably, this pad 103 can channel wound exudate and other fluids
through itself when negative pressure is applied to the wound. Some
pads 103 may include preformed channels or openings for such
purposes. In certain embodiments, the pad 103 may have a thickness
between about one inch and about two inches. The pad may also have
a length of between about 16 and 17 inches, and a width of between
about 11 and 12 inches. In other embodiments, the thickness, width,
and/or length can have other suitable values. Other aspects of the
pad 103 are discussed in further detail below. In some embodiments,
a pH indicator dye, as will be described in more detail later in
the specification, may be incorporated into the porous pad to
visually indicate the pH of the wound.
[0207] Preferably, a drape 107 is used to seal the wound site 510.
The drape 107 can be at least partially liquid impermeable, such
that at least a partial negative pressure may be maintained at the
wound site. Suitable materials for the drape 107 include, without
limitation, synthetic polymeric materials that do not significantly
absorb aqueous fluids, including polyolefins such as polyethylene
and polypropylene, polyurethanes, polysiloxanes, polyamides,
polyesters, and other copolymers and mixtures thereof. The
materials used in the drape may be hydrophobic or hydrophilic.
Examples of suitable materials include Transeal.RTM. available from
DeRoyal and OpSite.RTM. available from Smith & Nephew. In order
to aid patient comfoli and avoid skin maceration, the drapes in
certain embodiments are at least partly breathable, such that water
vapor is able to pass through without remaining trapped under the
dressing. An adhesive layer may be provided on at least a portion
the underside of the drape 107 to secure the drape to the skin of
the patient, although certain embodiments may instead use a
separate adhesive or adhesive strip. Optionally, a release layer
may be disposed over the adhesive layer to protect it prior to use
and to facilitate handling the drape 107; in some embodiments, the
release layer may be composed of multiple sections. In certain
embodiments, a pH indicator dye, as will be described in more
detail later in the specification, may be incorporated into the
drape to visually indicate the pH of the wound.
[0208] The negative pressure system 501 can be connected to a
source of negative pressure, for example a pump 114. One example of
a suitable pump is the Renasys EZ pump available from Smith &
Nephew. The drape 107 may be connected to the source of negative
pressure 114 via a conduit 112. The conduit 112 may be connected to
a port 113 situated over an aperture 109 in the drape 107, or else
the conduit 112 may be connected directly through the aperture 109
without the use of a port. In a further alternative, the conduit
may pass underneath the drape and extend from a side of the drape.
U.S. Pat. No. 7,524,315 discloses other similar aspects of negative
pressure systems and is hereby incorporated by reference in its
entirety and should be considered a part of this specification.
[0209] In many applications, a container or other storage unit 115
may be interposed between the source of negative pressure 114 and
the conduit 112 so as to permit wound exudate and other fluids
removed from the wound site to be stored without entering the
source of negative pressure. Certain types of negative pressure
sources--for example, peristaltic pumps--may also pemlit a
container 115 to be placed after the pump 114. Some embodiments may
also use a filter to prevent fluids, aerosols, and other microbial
contaminants from leaving the container 115 and/or entering the
source of negative pressure 114. Further embodiments may also
include a shut-off valve or occluding hydrophobic and/or oleophobic
filter in the container to prevent overflow; other embodiments may
include sensing means, such as capacitative sensors or other fluid
level detectors that act to stop or shut off the source of negative
pressure should the level of fluid in the container be nearing
capacity. At the pump exhaust, it may also be preferable to provide
an odor filter, such as an activated charcoal canister.
[0210] FIG. 20 illustrates an embodiment of a negative pressure
wound treatment comprising a wound dressing 2100 in combination
with a pump 2800. As stated above, the wound dressing 2100 can be
any wound dressing embodiment disclosed herein this section or
elsewhere in the specification or have any combination of features
of any number of wound dressing embodiments disclosed herein. Here,
the dressing 2100 may be placed over a wound as described
previously, and a conduit 2220 may then be connected to the port
2150, although in some embodiments the dressing 2100 may be
provided with at least a portion of the conduit 2220 pre-attached
to the port 2150. Preferably, the dressing 2100 is provided as a
single article with all wound dressing elements (including the port
2150) pre-attached and integrated into a single unit. The wound
dressing 2100 may then be connected, via the conduit 2220, to a
source of negative pressure such as the pump 2800. The pump 2800
can be miniaturized and portable, although larger conventional
pumps may also be used with the dressing 2100. In some embodiments,
the pump 2800 may be attached or mounted onto or adjacent the
dressing 2100. A connector 2221 may also be provided so as to
permit the conduit 2220 leading to the wound dressing 2100 to be
disconnected from the pump, which may be useful for example during
dressing changes. In certain embodiments, a pH indicator dye, as
will be described in more detail later in the specification, may be
incorporated into the wound dressing 2100 to visually indicate the
pH of the wound.
[0211] FIGS. 21A-D illustrate the use of an embodiment of a
negative pressure wound treatment system being used to treat a
wound site on a patient. FIG. 21A shows a wound site 2190 being
cleaned and prepared for treatment. Here, the healthy skin
surrounding the wound site 2190 is preferably cleaned and excess
hair removed or shaved. The wound site 2190 may also be irrigated
with sterile saline solution if necessary. Optionally, a skin
protectant may be applied to the skin surrounding the wound site
2190. If necessary, a wound packing material, such as foam or
gauze, may be placed in the wound site 2190. This may be preferable
if the wound site 2190 is a deeper wound.
[0212] After the skin surrounding the wound site 2190 is dry, and
with reference now to FIG. 21B, the wound dressing 2100 may be
positioned and placed over the wound site 2190. Preferably, the
wound dressing 2100 is placed with the wound contact layer 2102
over and/or in contact with the wound site 2190. In some
embodiments, an adhesive layer is provided on the lower surface
2101 of the wound contact layer 2102, which may in some cases be
protected by an optional release layer to be removed prior to
placement of the wound dressing 2100 over the wound site 2190.
Preferably, the dressing 2100 is positioned such that the port 2150
is in a raised position with respect to the remainder of the
dressing 2100 so as to avoid fluid pooling around the port. In some
embodiments, the dressing 2100 is positioned so that the port 2150
is not directly overlying the wound, and is level with or at a
higher point than the wound. To help ensure adequate sealing for
negative pressure wound therapy, the edges of the dressing 2100 are
preferably smoothed over to avoid creases or folds. In embodiments,
a pH indicator dye, as will be described in more detail later in
the specification, may be incorporated into the adhesive layer
and/or the wound contact layer to visually indicate the pH of the
wound.
[0213] With reference now to FIG. 21C, the dressing 2100 is
connected to the pump 2800. The pump 2800 is configured to apply
negative pressure to the wound site via the dressing 2100, and
typically through a conduit. In some embodiments, and as described
above in FIG. 20, a connector may be used to join the conduit from
the dressing 2100 to the pump 2800. Upon the application of
negative pressure with the pump 2800, the dressing 2100 may in some
embodiments partially collapse and present a wrinkled appearance as
a result of the evacuation of some or all of the air underneath the
dressing 2100. In some embodiments, the pump 2800 may be configured
to detect if any leaks are present in the dressing 2100, such as at
the interface between the dressing 2100 and the skin surrounding
the wound site 2190. Should a leak be found, such leak is
preferably remedied prior to continuing treatment.
[0214] Turning to FIG. 21D, additional fixation strips 2195 may
also be attached around the edges of the dressing 2100. Such
fixation strips 2195 may be advantageous in some situations so as
to provide additional sealing against the skin of the patient
surrounding the wound site 2190. For example, the fixation strips
2195 may provide additional sealing for when a patient is more
mobile. In some cases, the fixation strips 2195 may be used prior
to activation of the pump 2800, particularly if the dressing 2100
is placed over a difficult to reach or contoured area. Treatment of
the wound site 2190 preferably continues until the wound has
reached a desired level of healing. In some embodiments, it may be
desirable to replace the dressing 2100 after a certain time period
has elapsed, or if the dressing is full of wound fluids. During
such changes, the pump 2800 may be kept, with just the dressing
2100 being changed. In certain embodiments, a pH indicator dye, as
will be described in more detail later in the specification, may be
incorporated into the fixation strips to visually indicate the pH
of the wound.
[0215] FIG. 22 illustrates an embodiment of a negative pressure
wound treatment system 5501 employing a wound dressing 5500 in
conjunction with a flexible suction adapter 5512. The wound
dressing 5500 may be similar to the dressings illustrated in FIGS.
20-21D. Here, the flexible suction adapter 5512 may comprise a
bridge 5502 having a proximal end 5503 and a distal end 5505 and an
applicator 5504 at the distal end 5505 of the bridge 5502. A
connector 5504 is preferably disposed at the proximal end 5503 of
the bridge 5502. A cap 5536 may be provided with the system 5501
(and can in some cases, as illustrated, be attached to the
connector 5504). The cap 5536 can be useful in preventing fluids
from leaking out of the proximal end 5503. The system 5501 may
include a source of negative pressure such as a pump or negative
pressure unit 5534 capable of supplying negative pressure. The pump
optionally comprises a canister or other container for the storage
of wound exudates and other fluids that may be removed from the
wound. In some embodiments, the pump 5534 can be a PICO.TM. pump,
as sold by Smith & Nephew, which does not include a canister,
and wound exudate removed from the wound by negative pressure is
retained within the wound dressing. The pump 5534 may be connected
to the connector 5504 via a tube 5540. In use, the dressing 5500 is
placed over a suitably-prepared wound, which may in some cases be
filled with a wound packing material such as foam or gauze.
Subsequently, with the pump 5534 connected via the tube 5540 to the
connector 5504, the pump is activated, thereby supplying negative
pressure to the wound. Application of negative pressure may be
applied until a desired level of healing of the wound 5530 is
achieved.
[0216] With reference now to FIG. 23, which shares many of the
elements illustrated in the previous FIGS. 18-22, the embodiment of
the wound dressing illustrated here comprises the backing layer
2140, an optional masking layer 2107, and absorbent layer 2110. All
of these layers may optionally have a cut or opening made
therethrough which communicate directly to an optional transmission
layer 2105 so as to form an orifice 2145. Wound contact layer 2102
may be adhered to a lower surface of the backing layer 2140 to
enclose the absorbent layer 2110. The suction port 2150 is
preferably situated above an opening in the backing layer 2140 and
communicates with the optional orifice 2145. A filter (not shown)
may be provided on or below the suction port 2150 to prevent liquid
from passing through the opening in the backing layer 2140. In
certain embodiments, a pH indicator dye, as will be described in
more detail later in the specification, may be incorporated into
the filter to visually indicate the pH of the wound.
[0217] In particular for embodiments with a single port 2150, it
may be preferable for the port 2150 to be located in an off-center
position. Such a location may permit the dressing 2100 to be
positioned onto a patient such that the port 2150 is raised in
relation to the remainder of the dressing 2100. So positioned, the
port 2150 and the filter may be less likely to come into contact
with wound fluids that could prematurely occlude the filter so as
to impair the transmission of negative pressure to the wound
site.
[0218] FIG. 24 illustrates another embodiment of a wound dressing
3900. The wound dressing may comprise a release layer 3980, wound
contact layer 3960, a transmission layer 3950, an acquisition
distribution layer 3940, an adhesive layer 3970, an absorbent layer
3930, an obscuring layer 3920, and a backing layer 3910. One or
more of the aforementioned layers may be optional. Although FIG. 24
illustrates a dressing having one particular shape, the
construction of the layers can be applied to any of the embodiments
identified herein this section or elsewhere in the specification.
In certain embodiments, a pH indicator dye, as will be described in
more detail later in the specification, may be incorporated into
the release layer 3980, wound contact layer 3960, transmission
layer 3950, acquisition distribution layer 3940, adhesive layer
3970, absorbent layer 3930, obscuring layer 3920, and/or the
backing layer 3910 to visually indicate the pH of the wound. The
dressing may incorporate one or more viewing windows (not shown) to
allow a clinician and/or user to easily view any component within
the dressing that may be impregnated with a pH indicator dye. Such
viewing windows may be incorporated into any of the layers
overlying a layer incorporating a pH indicator dye. By utilizing
the one or more viewing windows, a clinician is then able to
monitor the pH of the wound through visually observing changes in
the color of the dressing component impregnated with a pH indicator
dye.
[0219] The dressing 3900 may be connected to a port (not shown)
provided over the opening 3911 in the backing layer 3910, such as
described with respect to the above embodiments. At least the
backing layer 3910, obscuring layer 3920, absorbent layer 3930, and
acquisition distribution layer 3940 may optionally have openings
underlying the port. In some embodiments, the opening 3921 in the
obscuring layer may be cross-shaped. As illustrated, the
cross-shaped opening 3921 may comprise four arms of roughly equal
length extending outward from a central point of intersection of
the arms, wherein the sides of each arm are angled or arced such
that the far end of each arm is wider than the end closest to the
intersection. The far ends of the four arms may comprise arcs, for
example four arcs from a single circle, giving the cross a rounded
shape. The opening 3911 in the backing layer 3910, opening 3931 in
the absorbent layer 3930, and opening 3941 in the acquisition
distribution layer 3940 may be aligned with the central
intersection point of the cross-shaped opening 3921. The openings
3911, 3931, and 3941 may be the same size or of varying sizes.
[0220] The backing layer 3910 (as well as the backing layer of
previously described embodiments) may comprise, in some
embodiments, EU33 film and may optionally have a pressure-sensitive
adhesive provided on a lower surface thereof. For example, the
adhesive may be a water dispersible acrylic adhesive, for example
KS. The adhesive may be able to be pattern spread, and may be
hydrophilic.
[0221] The obscuring layer 3920 may be provided to increase patient
comfort by masking the presence of wound exudate absorbed by the
inner layers of the dressing. The obscuring layer 3920 may have an
outer perimeter that is spaced 1 mm, or approximately 1 mm, or 0.5
mm to 3 mm, or approximately 0.5 to approximately 3 mm, beyond the
adjacent perimeter edge of the dressing layer or layers provided
beneath it, for example the absorbent layer 3930, AOL 3940, and/or
transmission layer 3950. The obscuring layer 3920 may be provided
with a plurality of viewing windows 3922 which may be used to
assess the spread of exudate across the dressing 3900. The
cross-shaped opening 3921 may be used as a viewing window to
ascertain the level of saturation of the layer or layers underlying
an attached port. The width of the cross-shaped opening 3921 may be
greater than the width of an attached port to enable such
assessment. Some embodiments of the obscuring layer 3920 (including
other embodiments of the obscuring layer previously described) may
comprise polypropylene spunbond material of suitable colors such as
described above, including medical blue. Further, some embodiments
of the obscuring layer 3420 may comprise a hydrophobic additive or
coating.
[0222] The absorbent layer 3930 may be configured to absorb and
retain exudate from a patient's wound. The absorbent layer 3930
will preferably be constructed from a material which has good
absorbent qualities under negative pressure. In some embodiments
(including any of the earlier described embodiments), the absorbent
layer may comprise cellulose fibers or air-laid materials. Some
embodiments may comprise a cellulose fibers with 40-80%
superabsorbent particles (SAP), for example 40%-60% (or about 40%
to about 60%) SAP or 60%-80% (or about 60% to about 80%) SAP. Heat
fusible fibers can optionally be used to assist in holding the
structure of the absorbent pad together. Some embodiments may
combine cellulose fibers and air-laid materials, for example as a
hybrid bonded airlaid composite in the range of 400-500 gsm (or
about 400 to about 500 gsm), for example 460 (or about 460) gsm.
The absorbent layer 3930 may include polyacrylate superabsorber
powder to increase the absorbent capabilities of the material. Some
embodiments of the absorbent layer 3930 comprise a tissue
dispersant layer. This may, in some embodiments, be provided along
the lower surface of the layer, resulting in an asymmetric
construction of the absorbent layer. The tissue dispersant layer
may comprise a heat fusible binder to aid in holding the layer
structure together. The tissue dispersant layer may provide the
advantage of enabling fluid transport. In some embodiments, the
tissue dispersant layer may comprise a hot melt adhesive such as
ethylene vinyl acetate (EVA), for example applied as a solution to
cellulose fibers of the absorbent layer.
[0223] The adhesive layer 3970 may bond an upper surface of the
acquisition distribution layer 3940 to a lower surface of the
absorbent layer 3930. As illustrated, in some embodiments the
adhesive layer 3970 may comprise an adhesive web or net. In other
embodiments, the adhesive layer 3970 may comprise adhesive tape.
Yet other embodiments may employ a hot melt adhesive, such as EVA.
For example, EVA powder may be sprinkled over the ADL 3940, which
may then be heat bonded to the adhesive layer 3970. In some
embodiments the acquisition distribution layer 3940 and the
absorbent layer 3930 may be stitched or sewn together, and the
adhesive layer 3970 may comprise suitable fibers, strands, or
threads. Preferred embodiments of the adhesive layer 3970 are
hydrophilic so as not to affect the transport of water and/or
water-based solutions between the acquisition distribution layer
3940 and absorbent layer 3930. In some embodiments, the adhesive
layer may comprise a fine sprinkle of adhesive powder such that the
acquisition distribution layer 3940 and absorbent layer 3930 are
not bonded together across the entire upper and lower surfaces,
respectively, but may be merely tacked together in a number of
locations. However, some embodiments of the dressing may be
constructed without the use of an adhesive between the acquisition
distribution layer 3940 and absorbent layer 3930.
[0224] The acquisition distribution layer (ADL) 3940 may be
constructed so as to advantageously horizontally wick fluid, such
as wound exudate, as it is absorbed upward through the layers of
the dressing 3900. Such lateral wicking of fluid may allow maximum
distribution of the fluid through the absorbent layer 3930,
enabling the absorbent layer 3930 to reach its full holding
capacity. Some embodiments of the ADL 3440 (including any
embodiments of the ADL previously described) may comprise cellulose
in the range of 40-160 gsm (or about 40 to about 160 gsm), for
example 80 (or about 80) gsm. The ADL may be constructed from a
material which resists compression under the levels of negative
pressure commonly applied during negative pressure therapy.
[0225] Some embodiments of the dressing 3900 may optionally
comprise a spacer or transmission layer 3950. The transmission
layer 3950 may comprise a porous material or 3D fabric configured
to allow for the passage of fluids therethrough away from the wound
site and into the upper layers of the dressing 3400. In particular,
the transmission layer 3450 should remain open under the typical
pressures that will be applied during negative pressure wound
therapy as described above, so that the whole wound site sees an
equalized negative pressure. In some embodiments, the acquisition
distribution layer 3940 may be sufficient to maintain even
transmission of negative pressure throughout the dressing 3900 and
the transmission layer 3950 may be excluded. An outer perimeter of
the transmission layer may be spaced 5 mm, or approximately 5 mm,
or 2 mm to 8 mm, or approximately 2 mm to approximately 8 mm,
inward of the adjacent perimeter edge of the dressing layer
positioned above the transmission layer, for example the ADL 3940
or absorbent layer 3930.
[0226] The dressing 3900 may optionally comprise a wound contact
layer 3960 for sealing the dressing 3900 to the healthy skin of a
patient surrounding a wound area. The wound contact layer 3960 may
comprise flexible polyurethane film, and may be provided with a
silicone adhesive on a lower surface thereof. The wound contact
layer 3960 may be perforated to allow for the transmission of
fluids such as wound exudate therethrough, so that the fluids may
be passed through or retained by the inner layers of the dressing
3900. Prior to use, the wound contact layer 3960 may be protected
by a protective release layer 3980, which may be provided with at
least one set of flaps 3981 for removing or peeling off the release
layer 3980.
[0227] Further details regarding wound dressings that may be
utilized with a negative pressure system, and further details
regarding negative pressure systems and their methods of use are
described in: PCT App. No. PCT/IB2013/002060, titled "Wound
Dressing and Method of Treatment," filed Jul. 31, 2013, U.S. Pat.
No. 8,791,315, titled Systems and Methods for Using Negative
Pressure Wound Therapy to Manage Open Abdominal Wounds," filed Sep.
20, 2010, and U.S. patent application Ser. No. 13/092,042, titled
"Wound Dressing and Method of Use," filed Apr. 21, 2011, all of
which are hereby incorporated by reference in their entirety.
[0228] FIG. 25A depicts a device 600 having a wound-contacting
surface 602 and an opposing non-wound-contacting surface 604. FIG.
25B depicts the device 600 in situ on a wound 606. The device 600
can be made of any material that is suitable for contact with the
wound. Wound contact layers are known in the art and include the
PROFORE wound contact non-adherent dressing (Smith and Nephew,
Inc), the MEPITEL Soft Silicone Wound Contact Layer (MOInlycke
Health Care US, LLC), CUTICERIN, a low-adherent acetate gauze
(Smith and Nephew, Inc) and the DRYNET Wound Veil (Smith and
Nephew, Inc). Conventionally wound contact layers arc characterised
by being conformable, transparent, non-adherent sheets that are
placed on or in an open wound bed to protect the tissue from direct
contact with other agents or dressings applied to the wound. Wound
contact layers arc also typically porous to allow wound exudate to
pass through for absorption by an overlying, secondary dressing.
Device 600 may be porous and can be a made of a non-woven, a
perforated film or a mesh. Alternatively, in applications in which
the device 600 is to be transiently placed into the wound to
measure pH between dressing changes, the device 600 may be
non-porous.
[0229] The device further includes a pH indicator 608 which is
applied to one or both of surfaces 602 and/or 604. The pH indicator
is immobilised on or adjacent to the surface 602 and/or 604 so that
it is not washed away by the wound exudate. As described elsewhere
in the Specification, the pH indicator may be utilized in
combination with the dressings disclosed in FIGS. 18-24. In
embodiments, the pH indicator may be incorporated into any of the
various components disclosed in the dressings of FIGS. 18-24.
[0230] In embodiments, the pH indicator is chemically bound to the
surface 602 and/or 604. For example, the pH indicator is covalently
bound to the surface 602 and/or 604. In alternative embodiments,
the surface 602 and/or 604 is provided within an adhesive and the
pH indicator is covalently bound to reactive moieties within the
adhesive. For example, a conventional acrylic adhesive, such as KS
(Smith & Nephew, Inc) used in the construction of wound
dressings contains residues of 2-hydroxy-ethylmethacrylate, which
provide a reactive functional hydroxyl (OH) group, pendant to the
polymer backbone, to which the pH indicator can be covalently
bound. Other suitable adhesives include acrylic-based adhesives
with pendant OH or COOH groups.
[0231] In alternative embodiments, the pH indicator is physically
entrapped at or adjacent to the surface. For example, the pH
indicator is entrapped within a soluble microsphere, for example a
microsphere made of a hydrophilic soluble polymer. Alternatively,
the pH indicator is retained between layers of a soluble material,
such as a polyvinyl alcohol film which is positioned adjacent to
the surface.
[0232] In embodiments on which the pH indicator is only applied to
one surface of a non-porous device, then an indication, for
indicating which side the pH indicator is applied to may be
provided. This indication allows the user to appropriately orient
the device during placement on or in a wound to ensure that the
surface which has the pH indicator provides the wound-contacting
surface.
[0233] The pH indicator may be applied across substantially the
entire surface 602 and/or 604, to allow the pH across the entire
wound bed to be mapped. Alternatively, the pH indicator may be
applied to discrete areas of surfaces 602 and/or 604. The pH
indicator exhibits a first colour prior to contact with a wound
exudate and changes colour as a function of the pH of the wound.
The first colour of the pH indicator may be colourless.
[0234] The pH indicator is capable of reversibly changing colour in
response to pH. In embodiments, the pH indicator is a phenylazo
compound. In certain embodiments, the phenylazo compound is
selected from the group listed in Table 1. In some embodiments, the
phenylazo compound is not
2-[4(2-hydroxyethylsulfonyl)-phenyl]diazenyl]-4-methylphenol. In
some embodiments, the phenylazo compound is not
hydroxy-4-[4[(hydroxyethylsulphonyl)-phenylazo]-napthalene-2-sulphonate.
In some embodiments, the phenylazo compound is not
2-fluoro-4-[4[(2-hydroxyethanesulphonyl)-phenylazo]-6-methoxy
phenol. In some embodiments, the phenylazo compound is not
4-[4-(2-hydroxyethylsulphonyl)-phenylazo]-2,6-dimethoxyphenol. In
certain embodiments, the phenylazo compound is
2-[4(2-hydroxyethylsulfonyl)-phenyl]diazenyl]-4-methylphenol. In
some embodiments, the pH indicator includes a plurality of
phenylazo compounds. In some embodiments, the pH indicator includes
a combination of phenylazo compounds, for example a combination of
phenylazo compounds selected from the group listed in Table 1. In
some embodiments, the pH indicator includes a combination of two
phenylazo compounds. In some embodiments, the pH indicator includes
a combination of three phenylazo compounds. In some embodiments,
2-[4(2-hydroxyethylsulfonyl)-phenyl]diazenyl]-4-methylphenol is
combined with at least one other phenylazo compound selected from
the group listed in Table 1. The ratio of phenylazo compound may be
1:1, but other ratios are envisaged, for example, but in no way
limiting, 0.5:1.5 or 1.5:0.5 or 1:2 or 2:1 or 1:0.1. In alternative
embodiments, the pH indicator includes at least one phenylazo
compound, for example a phenylazo compound selected from the group
listed in Table 1 and at least one other compound that is not a
phenylazo compound. In certain embodiments, the pH indicator is not
a phenylazo compound.
[0235] As shown in FIG. 26, the device 200 comprises a pH
indicating dye for indicating the pH of the wound exudate at the
wound surface. FIG. 26A shows a side cross-sectional view of a
device 200 which comprises a wound-contacting surface 202 and an
opposing non-wound-contacting surface 204. A pH indicator 208 is
provided on surface 202. The first colour of the pH indicator,
prior to contact with wound exudate, may be colourless. In some
embodiments, the device is an integral part of the wound dressing
and functions as the wound-contacting layer. In alternative
embodiments, the device is used in conjunction with a clinician's
choice of a secondary dressing. For example, the
non-wound-contacting surface 204 can be adhered to the wound-facing
surface of a secondary dressing. Alternatively, the device 200 can
be placed in or on the wound and the secondary dressing secured to
device 200 using, for example, adhesive tape or adhesive film.
[0236] FIG. 26B-D illustrate changes in wound pH over time and the
reversible response of the pH indicator 206. In FIG. 26B, the wound
dressing has been placed on the wound 206 and the pH indicator 208
has changed colour in response to a change in pH of the wound 206
exudate. For example, if the wound exudate has pH X, the pH
indicator 208 will change colour to the colour that is correlated
with pH X. Because the wound dressing is in situ this colour change
will not be visible unless the dressing is removed or the other
constituent parts of dressing are transparent. In FIG. 26C, the pH
of the wound exudate has altered to pH Y, and the pH indicator 208
changes colour in response to this pH change, with the colour of
the pH indicator changing colour to the colour that is correlated
with pH Y. Again, because the wound dressing is in situ this colour
change will not be visible unless the dressing is removed. In FIG.
26D, the pH of the wound has reverted to pH X and the pH indicator
208, due to its reversibility, has reverted to colour X. At this
point, the dressing is removed and the clinician can correlate the
colour X with a pH scale and determine that the pH is pH X. This
dressing thus provides a "snap shot" of the pH at the time of
dressing removal. The clinician will be unaware that the pH changed
to pH Y during the time that the dressing was in place.
[0237] FIG. 27 illustrates a wound dressing in which temporal
changes in pH can be monitored whilst the dressing is in situ on
the wound. FIG. 27A shows a side cross-sectional view of a wound
dressing 300 comprising an absorbent clement 304, the lower surface
of which is a wound contacting surface 306. The dressing also
comprises a pH indication zone 308 which is located at or adjacent
to the opposing non wound-contacting surface 310. This pH
indication zone includes a pH indicator (e.g., as disclosed herein)
which is capable of reversibly changing colour in response to
changes in pH. In this illustrated embodiment, the pH indication
zone 308 is disposed above the absorbent layer 304, so the pH
indicator can be monitored over time without having to remove the
dressing from the patient.
[0238] A transparent layer 312 overlays at least part of the pH
indication zone, which protects the integrity of the pH indicator
but still allows the clinician to monitor the colour of the pH
indicator over time. The dressing includes at least one conduit
that is configured to direct wound exudate from the wound to the pH
indication zone 308, ensuring that the pH of the wound exudate is
not materially altered as it passes through the components of the
wound dressing. One or a plurality of conduits could be used. As
shown in FIG. 27, two conduits are used, although one or more other
conduits could also be included. The two conduits 314 and 316 are
oriented vertically and extend across the absorbent layer. The
conduits are preferably sealed, so as not to exchange fluid with
the absorbent layer, but are in communication with the pH
indication zone 308 and direct the wound exudate to the pH
indication zone 308 located in the upper part of the dressing. The
conduits may be in the form of narrow capillaries which transmit
the fluid towards the pH indication zone 308. The conduits may
incorporate or may be form led from wicking materials, for example,
woven, non-woven, knitted, tows or fibres made of suitable
materials to facilitate wicking of the wound exudate towards the pH
indication zone 308. In alternative embodiments, a pH indication
zone is provided at or near a lateral edge 318 or 320 of the
dressing and at least one conduit is provided within the dressing
to direct the wound exudate laterally to the pH indication zone. In
some embodiments, the pH indication zone is provided in a layer of
the dressing which forms an outer surface of the dressing and a
transparent cover layer is not used. In some embodiments, the
conduits may take the form of a long strip or be of an elongated
lozenge shape when viewed from the wound contact surface.
Alternatively, the conduit may be formed of crosses or
quadrilateral shapes. In this way it is possible to transmit wound
exudate across the area of the wound to the pH indication zone.
[0239] Whilst FIG. 27 depicts a discrete pH indication zone that is
provided above the absorbent element, it is envisaged that the pH
indication zone can be provided in alternative locations within the
dressings. It is also envisaged that the pH indication zone can
exhibit additional functionality. For example, the dressing can
comprise any combination of the following components; a top film, a
super-absorbent layer, an absorbent layer, a spacer layer and a
wound contact layer, with each component being present in the
singular or plural, and the pH indication zone is or is provided
within at least one of these layers. In alternative embodiments, an
adhesive layer associated with at least one of these layers
consists of or comprises the pH indication zone. Example wound
dressing assemblies include, but are not limited to;
[0240] (a) Top film; pH indication zone; wound contacting
layer;
[0241] (b) Top film; pH indication zone; spacer layer; wound
contacting layer;
[0242] (c) Top film; spacer layer (=pH indication zone); wound
contacting layer;
[0243] (d) Top film; pH indication zone; spacer layer; absorbent
layer; wound contacting layer;
[0244] (e) Top film; pH indication zone; spacer layer;
super-absorbent layer; absorbent layer, wound contacting layer;
[0245] (f) Top film; pH indication zone; spacer layer;
super-absorbent layer; wound contacting layer;
[0246] (g) Top film, pH indication zone; absorbent layer; wound
contacting layer;
[0247] (h) Top film, pH indication zone; super-absorbent layer;
wound contacting layer.
[0248] Methods of immobilising a phenylazo dye on the devices
and/or wound dressings illustrated in FIGS. 18-27 are also
contemplated.
[0249] An example includes the following steps:
[0250] In a first step, 25 mg of a phenylazo pH indicating dye, for
example a phenylazo pH indicating dye selected from the group
listed in Table 1, is reacted with 140 .mu.l concentrated sulphuric
acid for 30 mins to form a dye solution.
[0251] In a second step, 200 ml of distilled water is added to the
dye solution formed in the first step.
[0252] In a third step, 406 .mu.l of a 32% w/v solution of sodium
hydroxide is added to the solution formed in the second step.
[0253] In a fourth step, 25.45 ml of a 2.36M solution of sodium
carbonate is added to the solution formed in the third step.
[0254] In a fifth step, 1.35 ml of a 32% w/v solution of sodium
hydroxide is added to the solution formed in the fourth step and
the volume made up to 250 ml with distilled water.
[0255] In a sixth step, a material on which the pH indicating dye
is to be bound is placed in the solution and left to react for
approximately 1-2 hours. Examples of suitable materials include,
but are not limited to: TENCEL fibres of the Durafiber product,
polyurethane foam of the Allevyn product, cellulose pad of the
Post-op product, or K5 adhesive-coated polyurethane film, all
available from Smith & Nephew, Inc. The material is then washed
with distilled water until no more dye is released. The material is
then dried.
EXAMPLES SECTION 1 AND 2
[0256] A sample of the pad from an Opsite Post-Op dressing (Smith
& Nephew, Inc) was prepared in different samples, and each
sample was covalently bound with one or a combination of phenylazo
dyes, selected from GJM-514, GJM-492, GJM-546, and GJM-534. The
structures of these dyes are shown in Table 1. It was discovered
that these dyes had colour-changing characteristics that varied
according to changes in pH. The Post-Op samples were covalently
bound with GJM-514 alone or with GJM-514 combined with one of
GJM-492, GJM-546 and GJM-534 using the method as described above in
relation to FIGS. 1-3. The Post-Op material was exposed to buffered
solutions having a pH of 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9 and 9.5.
Photographs were taken of each sample to demonstrate the visible
changes in colour. A colour pen (for example, Dr Lange Colour Pen),
a pen-type colorimeter was used to detect marginal colour changes
which arc undetectable by the human eye. Colour pen measurements
include, but arc not limited, to three different readings: the L*,
a* and b* values. [0257] L* represents the lightness/luminosity of
the colour [0258] L*=0 is black [0259] L*=100 is diffuse white
[0260] a* is the colour's position between red/magenta and green
[0261] A positive a* value indicates magenta [0262] A negative a*
value indicates green [0263] b* is the colours position between
yellow and blue [0264] a positive b* value indicates yellow [0265]
a negative b* value indicates blue
Example 1: Post-Op Pad Dyed with GJM-514
[0266] A sample of the pad from an Opsite Post-Op dressing (Smith
& Nephew) was covalently bound with the dye GJM-514 was exposed
to buffered solutions at pH 5-pH 9.5. The panel of photographs in
FIG. 3 demonstrates the colour change of GJM-514 over this pH
range, going from yellow in colour (at pH5) to pink (at pH
9.5).
[0267] Table 2 illustrates the colour pen measurements (L*, a* and
b*) of the colour of the GJM-514 dye over a pH range of pH 5-pH
9.5. An optimal dye for use as a pH indicator is one which
demonstrates a linear change in a measurement of a specific
parameter of colour (for example L*, a* orb*) over a broad pH
range. Outside of the linear region, the dye is either unable to
change colour in response to a change in pH or the change in colour
is so minimal that it is undetectable.
TABLE-US-00002 TABLE 2 pH L* a* b* 5 63.3 -1.9 41.5 5.5 69.2 0.3
36.2 6 65.7 1.4 35.1 6.5 59.3 1.2 35.5 7 56.9 2 33.6 7.5 55.4 4.8
30.6 8 46.8 10.4 21.4 8.5 43.3 15.6 15.4 9 40.2 21.3 8.7 9.5 37.5
24.8 4.9
[0268] FIGS. 4A and 4B illustrate the L* measurements taken of the
GJM-514 dye with the colour pen presented graphically. The L*
results of FIG. 4A show that the L* value decreases from pH 5.5 to
pH 9.5 as the luminosity of the dye decreases relative to the
increasing pH. These results have also been plotted in FIG. 4B and
demonstrate a linear region between pH 7.5 and 9.5. The trend line
has a gradient of -8.18 and an R2 value of 0.9918.
[0269] FIGS. 4C and 4D illustrate the a* measurements taken of the
GJM-514 dye with the colour pen presented graphically. FIG. 4C
illustrates the a* measurements taken at various pH values between
pH 5-pH 9.5. FIG. 4D illustrates the a* measurements at various pH
values over the linear portion of the trend line, between pH 7.5
and 9. The trend line has a gradient of 10.94 and an R.sup.2 value
of 0.9997.
[0270] FIGS. 4E and 4F illustrate a graphical representation of the
b* measurements taken of the GJM-514 dye. FIG. 4E shows the b*
measurements taken at various pH values between pH 5-pH 9.5. FIG.
4E illustrates the b* measurements at various pH values over the
linear portion of a trend line. From FIG. 4E it can be seen that
the values are fairly consistent and steady between pH 5.5 and pH
7, and after pH 7 they start to decrease. FIG. 4F shows that the
results give a linear downward trend between pH 7.5 and pH 9, with
a gradient of -14.34 and an R.sup.2 value of 0.991.
[0271] Taking into account the colour pen results and photographs
of the samples, the most accurate working range for GJM514 is
between pH 7.5 and pH 9. The linear trend line of the b*
measurements has a steeper gradient (-14.34) than the a*
measurements (10.94) and therefore b* would be used preferentially
to give a more accurate indication of the pH of the dressing when
using an optical reader rather than the human eye.
Example 2: Post-Op Pad Dyed with GJM-514: GJM-492 (1:1)
[0272] A sample of the pad from an Opsite Post-Op dressing (Smith
& Nephew) was covalently bound with the dye GJM-514: GJM-492 at
a 1:1 ratio was exposed to buffered solutions at pH 5-pH 9.5. The
panel of photographs in FIG. 5 demonstrates the colour change over
this pH range, going from yellow in colour (at pH 5) to orange in
colour (at pH 9.5).
[0273] Table 3 illustrates the colour pen measurements (L*, a* and
b*) of the colour of the GJM-514: GJM-492 dye combination over a pH
range of pH 5-pH 9.5.
TABLE-US-00003 TABLE 3 pH L* a* b* 5 53.8 11.5 43.3 5.5 50.7 17.4
37.9 6 45.3 23.9 37.5 6.5 40.4 29.9 35.4 7 39.7 30.9 33.8 7.5 39.9
30.4 29.9 8 34.5 31.5 29.2 8.5 37.4 28 29.3 9 33.8 30.7 25 9.5 33.1
31.3 23.2
[0274] FIG. 6A illustrates the L* measurements taken with the
colour pen presented graphically. The L* results presented in FIG.
6A show that the value for L* decreases over the range of pH 5.5 to
pH 9.5 but does not follow a linear downward trend. The L* value is
therefore not considered to be a reliable indicator of the colour
change of this dye combination over the pH range tested.
[0275] FIGS. 6B and 6C illustrate the a* measurements taken with
the colour pen presented graphically. FIG. 6B illustrates the a*
measurements taken at various pH values between pH 5-pH 9.5. FIG.
6C illustrates the a* measurements at various pH values over the
linear portion of a-trend line. An upwardly linear trend
(gradient=12.34, R.sup.2=0.9997) is identifiable between pH 5 and
6.5, demonstrating that there is a detectable change in colour
along the red/magenta to green scale over this pH range.
[0276] FIG. 6D illustrates a graphical representation of the b*
measurements taken with the colour pen. It can be seen that there
is not a significant change in b* value, but there is a downwards
trend.
[0277] Taking into account the colour pen results and photographs
of the samples, the working range for this dye combination appears
to be between pH 5 and pH 6.5. With a* giving a useable trend line
for this region that could be used to estimate the pH from the
material colour.
Example 3: Post-Op Pad Dyed with GJM-514: GJM-546 (1:1)
[0278] A sample of the pad from an Opsite Post-Op dressing (Smith
& Nephew) was covalently bound with the dye GJM 514:546 at a
1:1 ratio was exposed to buffered solutions at pH 5-pH 9.5. The
panel of photographs in FIG. 7 demonstrates the colour change over
this pH range, going from orange in colour (at pH 5) to pink (at pH
9.5).
[0279] Table 4 illustrates the colour pen measurements (L*, a* and
b*) of the colour of the GJM-514: GJM-546 dye combination over a pH
range of pH 5-pH 9.5.
TABLE-US-00004 TABLE 4 pH L* a* b* 5 45.7 22.7 44.1 5.5 43.4 22.8
40.1 6 43.9 24.8 34.6 6.5 36.5 27 25 7 33.4 25.7 16 7.5 28.3 27.8
7.1 8 26.9 26.6 1.3 8.5 25.6 29.3 -0.7 9 24.5 28.8 -2.3 9.5 23.9
29.5 -3.8
[0280] FIGS. 8A and 8B illustrate a graphical representation of the
L* measurements taken with the colour pen. FIG. 8A shows all data
points whilst FIG. 8B is a re-plot of the data points in the linear
region between pH S to pH 8. The trend line has a gradient of
-6.3702 with an R.sup.2 value of 0.9982.
[0281] FIG. 8C illustrate the a* measurements taken with the colour
pen presented graphically over the pH 5-pH 9.5 range. The results
are too variable for the a* measurement to be considered of use in
reliably measuring a colour change in the GJM 514:546 dye
combination in response to changes in pH.
[0282] FIGS. 8D and 8E illustrate a graphical representation of the
b* measurements taken with the colour pen. FIG. 8E shows the b*
measurements taken at various pH values between pH 5-pH 9.5 and it
can be seen that the results follow a downward trend from -pH 5 to
pH 8, but it appears to plateau after pH 8. FIG. 8E illustrates the
b* measurements at various pH values over the linear portion of a
trend line which has a gradient of -18.3 and an R.sup.2 of 0.9997.
As the b* results gave a steeper gradient it is believed that
monitoring the b* value would give a more accurate reading of the
pH from the dressing colour. The working range for this dye
combination appears to be pH 6 to pH 7.5.
Example 4: Post-Op Pad Dyed with GJM 514:534 (1:1)
[0283] A sample of the pad from an Opsite. Post-Op dressing (Smith
& Nephew) was covalently bound with the dye GJM-514:534 at a
1:1 ratio was exposed to buffered solutions at pH 5-pH 9.5. The
panel of photographs in FIG. 9 demonstrates the colour change over
this pH range, going from yellow in colour (at pH 5) to red in
colour (at pH 9.5).
[0284] Table 5 illustrates the colour pen measurements (L*, a* and
b*) of the colour of the GJM-514: GJM-534 dye combination over a pH
range of pH 5-pH 9.5
TABLE-US-00005 TABLE 5 pH L* a* b* 5 53.4 6.1 50.3 5.5 52.3 7.5
45.4 6 53.8 7.6 46.1 6.5 49.7 9.8 35.4 7 43.1 16.2 29.9 7.5 37.4
16.2 18.9 8 33.4 20.4 11.9 8.5 31.9 22.8 5.3 9 27.7 27.6 3.6 9.5
28.9 29.1 -0.5
[0285] FIGS. 10A and 10B illustrate a graphical representation of
the L* measurements taken with the colour pen. FIG. 10A shows all
data points whilst FIG. 10B shows only those data points in the
linear region. A general downward trend from pH 6 to pH 9 is
observed. The trend line has a gradient of -8.8286 and an R.sup.2
value of 0.9742.
[0286] FIGS. 10C and 10D illustrate the a* measurements taken with
the colour pen presented graphically. FIG. 10C illustrates the a*
measurements taken at various pH values between pH 5-pH 9.5. FIG.
10D illustrates the a* measurements at various pH values over the
linear portion of a trend line. The results demonstrate an upwards
trend between pH 6 to pH 9, with the trend line having a gradient
of 6.6335 and an R.sup.2 value of 0:9924.
[0287] FIGS. 10E and 10F illustrate a graphical representation of
the b* measurements taken with the colour pen. FIG. 10E shows the
b* measurements taken at various pH values between pH 5-pH 9.5 and
it can be seen that the results follow a downward trend until pH 9.
The trend line illustrated in FIG. 10F has a gradient -16.314 and
an R.sup.2 value of 0.9925 between pH 6 and pH9. From the colour
pen measurements the working range of this dye combination is
between pH 6 and pH 9, and the b* value could be used to accurately
measure the pH from the material colour.
Example 5: Post-Op Pad Dyed with GJM 514:534 (1:0.509)
[0288] A sample of the pad from an Opsite Post-Op dressing (Smith'
& Nephew) was covalently bound with the dye GJM 514:534 at a
1:0.509 ratio was exposed to buffered solutions at pH 5-pH 9.5. The
panel of photographs in FIG. 11 demonstrates the colour change over
this pH range, going from yellow in colour (at pH 5) to red in
colour (at pH 9.5).
[0289] Table 6 illustrates the colour pen measurements (L*, a* and
b*) of the colour of the GJM-514:GJM-534 dye combination over a pH
range of pH 5-pH 9.5.
TABLE-US-00006 TABLE 6 pH L* a* b* 5 55.4 4.9 43.1 5.5 57.6 2.9
42.6 6 56.8 3.4 42.7 6.5 51.2 5 40 7 49 8.8 34.7 7.5 39.8 11.4 23.5
8 39 17.6 15 8.5 36.5 22.4 10.1 9 34.2 24.3 5.8 9.5 32.3 25.3
0.3
[0290] FIG. 12A illustrates a graphical representation of the L*
measurements taken with the colour pen. A general downward trend
from pH 6 to pH 9.5 is observed.
[0291] FIGS. 12B and 12C illustrate the a* measurements taken with
the colour pen presented graphically. FIG. 12B illustrates the a*
measurements taken at various pH values between pH 5-pH 9.5. FIG.
12C illustrates the a* measurements at various pH values over the
linear portion of a trend line. The results demonstrate a linear
upwards trend between pH 6.5 to pH 8.5, with the trend line having
a gradient of 8.72 and an R.sup.2 value of 0.9987.
[0292] FIGS. 12D and 12E illustrate a graphical representation of
the b* measurements taken with the colour pen. FIG. 12D shows the
b* measurements taken at various pH values between pH 5-pH 9.5 and
it can be seen that the results follow a downward trend between pH
6 and pH 8.5. The trend line illustrated in FIG. 12E has a gradient
15.9 and an R.sup.2 value of 0.9833. Taking into account the colour
pen results and the photographs of the samples, the working range
of this dye combination is between pH 6 and pH 8.5, and the b*
value could be used to accurately measure the pH from the material
colour.
Examples 6 and 7
[0293] Further to the above general method for preparing covalently
bonded dye, different materials were also used unto which to bind
the dye.
[0294] A sample of a gauze (Kerlix Trademark of Covidiene) and
polyvinyl alcohol foam (V.A.C. White Foam, trade mark of KCl) were
covalently bound with the dye GJM-546 and 492 in a ratio 1:3.92 as
described throughout this disclosure.
[0295] These latter materials can be used as pH sensing fillers for
Negative Pressure Wound Therapy (NPWT). They were evaluated by use
of the following models and experiments.
Materials
TABLE-US-00007 [0296] Material Pork Meat (loin or shoulder 2 kg
approx. Intact skin and a surface area 20 .times. 20 cm approx.) pH
sensitive VAC foam pH sensitive gauze Renasys drapes Horse serum
Citric Acid Sodium Bicarbonate Equipment Renasys EZ plus pump
Peristaltic pump Renasys EZ canister Epidural needle Clingfilm
Tubing Glass Dish Scalpel pH meter
Method
[0297] Use these solutions to adjust horse serum to pH 5 and pH 8,
for use in the meat mode. [0298] 1. Place a sheet of cling film in
the bottom of a glass dish/tray and place a piece of pork with
intact skin upwards on the cling film. [0299] 2. Wrap the meat in
the cling film and add more if necessary so that the meat is
completely sealed. [0300] 3. Using a scalpel create 2 wounds each
approximately 50 mm in diameter and 25 mm deep in the tissue (and
at least 2 cm apart), by removing the skin/fat/muscle, with a
relatively flat bottom and minimal tissue flaps. [0301] 4. Insert
an epidural catheter needle through the side of the wound so that
the tip appears at the outside edge of the meat. Use the needle to
feed the peristaltic pump tubing through so that it lies at the
base of the wound. (Repeat for the other wound). [0302] 5. Using
small pieces of Flexi-fix and/or adhesive putty ("white-tac")
secure and seal the openings where the fluid tubes exit the cling
film. [0303] 6. The following combinations are to be tested: [0304]
a. Dyed VAC foam [0305] b. Dyed gauze [0306] 7. Add foam to bridge
onto intact healthy skin and link both bridges together to work
from a single port. Seal over the wounds, fillers and bridging foam
with drapes. [0307] 8. Make a small hole in the drape where it lies
over a foam bridge and attach a port using Flexi-fix strips. [0308]
9. Connect the port to a RENASYS NPWT pump (set at -120 mmHg) and
switch on. [0309] 10. Turn on the peristaltic pump (set to deliver
40 .mu.l/min) to deliver fluid to the wound bed of horse serum at
pH 8. [0310] 11. Monitor the dressings until fluid stalis to appear
in the canister (make a note of the length of time) [0311] 12.
Change the fluid to horse serum at a pH of 5, and leave to flow for
the amount of time determined in step 11). Then take a photograph
of the dressings. [0312] 13. Change the fluid to horse serum at a
pH of 8, and leave to flow for the amount of time determined in
step 11). Then take a photograph of the dressings. [0313] 14.
Change the fluid back to horse serum at a pH of 5, and leave to
flow for the amount of time determined in step 11). Then take a
photograph of the dressings. [0314] 15. At the end of the
experiment disconnect the tubing and seal the meat in cling film
for disposal. Clean all surfaces that had contact with the meat
with soap/water. Determination of the ability of dyed VAC foam and
gauze to detect changes in pH of wound fluid. The pH sensitive
gauze and VAC foam were washed after the first meat model
experiment and then used in an additional wound model, with pH
adjusted water. In addition the extra piece of pH sensitive dyed
gauze was placed in a clear Perspex wound model and fluid pumped
through. All wound models were monitored by taking photographs,
those carried out in meat could only be monitored from the top
surface, but the clear Perspex model could be monitored from all
sides.
Results and Discussion
[0315] The foam was orange in colour when it was loaded into the
wound, but the gauze was more of a red colour. It is believed the
gauze is red in colour due to the presence of PHMB on the gauze
which would make it basic.
Meat Model 1
[0316] The experiment was started by pumping pH 5 horse serum into
the wound filler for approximately 2.5 hours before fluid started
to appear in the canister and the material started to change
colour. After approximately 5.5 hours the pH 5 horse serum solution
was changed to pH 8 horse serum and this was run overnight. In the
morning the solution was then changed back to pH 5 horse serum and
was pumped in for several hours (due to time restrictions the flow
rate was increased to 800/min after 3.5 hours).
[0317] The images of the pH sensitive dyed gauze changing over time
can be seen in FIGS. 13A to 13F; showing that the gauze had started
to go orange after 5.5 hours of exposure to pH 5 horse serum and
after a night of exposure to pH 8 serum the gauze had returned to a
red colour. Then after several hours of exposure to pH 5 the gauze
was starting to turn orange again at which time the experiment was
ended. Upon removal of the gauze it could be seen that the bottom
of the gauze was mostly orange and it could be seen that the colour
and therefore the pH were changing through the gauze in a direction
from the wound bed towards the drape, which can be explained by the
fact that the wound tends to fill up like the filling of a bath and
therefore the pH takes time to change from one pH to the other as
the pumped fluid is slowly transported through the wound
filler.
[0318] Images of the pH sensitive dyed VAC foam changing over time
can be seen in FIGS. 14A to 14F. They show that the foam had gone
yellow when exposed to pH 5 horse serum (5.5 hours image), and that
when exposed to pH 8 overnight the foam went red. As with the gauze
the foam had started to turn yellow/orange after re-exposure to pH
5 serum for several hours before the experiment was ended, the
yellow/orange colour can most clearly be seen near the bridging
foam.
Meat Model 2
[0319] For the second meat model the basic aqueous solution was
used first and was left pumping into the model overnight. The next
morning the solution was then changed to an acidic aqueous solution
and left pumping for several hours.
[0320] The images for the pH sensitive gauze can be seen in FIGS.
15A to 15F and show that the gauze went red in colour in basic
solution and within 5 hours of the fluid being switched to acidic
aqueous solution the gauze had started to turn orange. It is
believed that this colour change will originate at the base of the
wound and work its way up to the surface as the pH in the wound
changes, which as mentioned earlier would be similar to the way in
which a bath fills up. It is clear the colour change on the surface
starts near the area directly below the port, this can be explained
as this is the destination (exit point) of the fluid and so the pH
would stabilises around this area on the surface first.
[0321] The same trend is seen with the dyed VAC foam, as shown in
FIGS. 16A to 16F. The foam turns red when in the presence of basic
fluid and when the fluid is changed to acidic the foam starts to
turn yellow in colour Like the gauze the colour change seen on the
surface is first noticeable around the port where the fluid is
removed from the wound.
Clear Perspex Wound Model
[0322] The experiment was also carried out using the pH sensitive
dyed gauze in a clear Perspex wound model to be able to visualise
the colour change throughout the wound. The fluid was not pumped in
from the bottom on this occasion but from the left hand side of the
wound as seen on the images in FIGS. 17A to 17H. The fluid inlet is
on the same side as the port and halfway up the wound wall. It is
believed that the area of this wound is smaller than those created
in the meat, hence the colour change occurring faster as the pump
speed is the same in both experiments. It can be seen that as the
basic fluid is pumped into the wound the gauze turns red (at T=O
hours there was already some basic fluid in the wound hence part of
the gauze already being red in colour). It can be seen from all the
images in FIGS. 17A to 17H, both the top surface of the wound (top
image) and the bottom (bottom image of each pair), that the colour
change moves across the wound from left to right and that the
bottom of the wound is slightly ahead of the upper surface of the
wound. This colour change pattern is as expected, as fluid fills up
from the bottom and so the pH changes at the bottom before the top.
The Perspex model is not as realistic as the meat model as the
fluid and content from the meat would mean that the pH could take
longer to change due to possible buffering effects.
CONCLUSIONS AND RECOMMENDATIONS SECTION 1
[0323] Both the pH sensitive dyed VAC foam and gauze, changed
colour as they were exposed to different pH solutions. The colours
for indicating the different pH's were clearly visible, and the
colour could be reversed by addition of the other pH solution to
the wound.
DETAILED DESCRIPTION SECTION 3
[0324] To provide an understanding of the devices and methods
describe herein, certain illustrative embodiments will now be
described. For the purpose of clarity and illustration, the devices
herein are described as having a pH-dependent moisture indicator
which changes colour in response to a pH change.
[0325] Reference numbers cited in Section 3 correspond to the
reference numbers used in FIGS. 28-32.
[0326] FIG. 28 A depicts a device 100 which is designed to be
incorporated into a wound dressing in order to indicate the wound
exudate loading of the dressing, as will be explained in greater
detail below. Device 100 has a first carrier material 102, which
can be any material that is permeable to liquid, such as wound
exudate. For example, the first carrier material 102 can be a
cellulosic material. A suitable cellulosic material is conventional
filter paper. The first carrier material 102 has a wound facing
surface 104 and an opposing non-wound facing surface 106. The first
carrier material 102 is impregnated with a soluble composition 108
which is a source of hydrogen or hydroxide ions, upon
solubilisation by wound exudate. In certain embodiments, the source
of hydrogen ions is an acid, such as citric acid. In alternative
embodiments, the source of hydroxide ions is an alkali, such as
sodium carbonate.
[0327] The device also includes a second carrier material 110 which
has a wound facing surface 112 and an opposing non-wound facing
surface 114. The wound facing surface 112 is located on or adjacent
to the non-wound facing surface 106 of the first carrier material
102. In certain implementations, the two surfaces 112 and 106 form
a composite. The second carrier material 110 is preferably white,
although it is envisaged that other colours could be utilised. The
second carrier material 110 is impregnated with a pH indicator 116
which has a first colour and which can change to a second colour
upon interaction with hydrogen or hydroxide ions. The second colour
is indicative of the pH of the ion-loaded wound exudate. Suitable
pH indicators that indicate pH based upon colour are readily
apparent to persons skilled in the art, and include for example, a
universal indicator solution.
[0328] As shown in FIG. 28B, when wound exudate 118 migrates into
the first carrier material 112, the soluble composition 108 is at
least partially solubilised to release hydrogen or hydroxide ions
into the wound exudate. The ions are carried within the wound
exudate into the second carrier material 110 as the wound exudate
migrates through the dressing. Within the first carrier material
103 the ions interact with the pH indicator. This interaction
causes the pH indicator to change from the first colour to the
second colour. Because the ion-loaded wound exudate has a pH which
is more acidic or more alkaline than the endogenous, unmodified,
wound exudate there is a greater shift in the colour of the pH
indicator than would occur with endogenous wound exudate. This
colour change is thus amplified and easier to perceive by the user.
A consideration to be made when choosing the species and
concentration of the soluble solution to use in the device is that
the release of hydrogen or hydroxide ions into the wound exudate
should preferably result in the pH of the wound exudate becoming
either very acidic (for example, pH 0, pH 1, pH 2, pH 3) or very
alkaline (for example, pH 11, pH 12, pH 13 or pH 14) as changes to
these pH's produce colours which are less ambiguous to the patient
and/or clinician than colours in the intervening pH range. Also
preferred is to minimise the neutralisation of the hydrogen and
hydroxide ions by the endogenous wound exudate. It is therefore
envisaged that a range of devices can be available, each having
different combinations of soluble compositions (e.g., species and
concentrations) and pH indicators. This enables the clinician to
tailor the use of the device to the clinical situation, for example
the wound type. The clinician can test the pH of the endogenous
wound fluid and choose the appropriate device accordingly, that is
the device which will provide the most perceivable shift in colour
upon contact with the ion-loaded wound exudate.
[0329] In certain embodiments, the source of hydrogen ions is
citric acid and the pH indicator is a universal indicator solution.
The universal indicator is loaded onto a cellulosic second carrier
material 110 at neutral pH and has a first colour of yellow/orange.
The hydrogen ions released by the solubilisation of the citric acid
interact with the universal indicator, forcing a change to the
second colour. The second colour is red.
[0330] In certain embodiments, the source of hydroxide ions is
sodium carbonate and the pH indicator is universal indicator. The
universal indicator is loaded onto a cellulosic second carrier
material 110 at neutral pH and has a first colour of yellow/orange.
The hydroxide ions released by the sodium carbonate interact with
the universal indicator, forcing a change to the second colour. The
second colour is violet/purple.
[0331] FIGS. 29A and 29B depict device 200 which is similar to the
device illustrated in FIGS. 28A and 28B and which additionally
includes a spacer layer 220 positioned between the first carrier
material 202 and the second carrier material 210. The device is
designed to be incorporated into a wound dressing in order to
indicate the wound exudate loading of the dressing. Wound dressings
are sterilised before use, and one conventional means of
sterilization uses ethylene oxide. A typical treatment protocol
contains a high humidity cycle and this risks some degree of
premature solubilisation of the soluble composition 208 due to
contact with the moisture. The premature solubilisation and
consequent interaction of the ions with the pH indicator would be
detrimental to the functionality of the product, leading to false
results. For example, it could appear that the dressing is
saturated, when in fact it is not, leading to unnecessary dressing
changes. Minimising premature interaction between the soluble
composition and the pH indicator is therefore desirable. This is
achieved by physically separating these components within the
device so that even if some degree of solubilisation of the soluble
composition results from the sterilisation protocol, the ions
released are unable to sufficiently interact with the pH indicator
to cause a colour change. The spacer layer 220 is therefore
incorporated into the device to physically separate the pH
indicator 216 and the source of hydrogen or hydroxide ions 208.
[0332] The spacer layer 220 can be made of any material that allows
a wound exudate which is loaded with ions to migrate through
towards the second carrier material. The type of material and its
morphology can be chosen in order to tune the moisture level that
is required to trigger the indicator system. In some embodiments
the spacer layer 220 is a cellulose-based paper, for example, a
conventional filter paper. In certain embodiments, the spacer layer
220 is a 3-D fabric, for example, the spacer layer can be a knitted
or woven spacer fabric, such as Baltex 7970 weft knitted polyester.
In certain embodiments, the spacer layer is a non-woven fabric.
[0333] In certain embodiments, the spacer layer is a composite
which utilises the differential between filament counts to promote
and direct the transport of wound exudate upwards through the
device. For example, the spacer layer can consist of a layer of
knitted polyester viscose, cellulose or other monofilament fiber
which is sandwiched between an upper layer of 84/144 textured
polyester and a lower layer of 100 denier flat polyester.
[0334] In order to promote wound exudate transport through the
spacer layer, the material of the spacer layer is advantageously
hydrophilic. In certain embodiments, the material is inherently
hydrophilic. Alternatively, a hydrophilic coating can be applied to
the material in order to increase the hydrophilic nature of the
material. Alternatively, treatments to increase the hydrophilic
nature of the material, for example by removing any manufacturing
products such as mineral oils, fats and/or waxes may be utilised.
Suitable cleaning treatments may include washing with dry cleaning
agents, such as perchloroethylene and/or aqueous cleaning agents
such as ionic and non-ionic detergents in aqueous solution.
Optionally, an additional manufacturing step can subsequently be
carried out in which the 3D spacer fabric is washed in a
hydrophilic agent (such as, but not limited to, Feran Ice 30 g/l
available from the Rudolph Group).
[0335] FIG. 30A depicts an alternative embodiment, device 300 which
has a single layer of carrier material 240 that is impregnated with
both a soluble composition 260 and a pH indicator 280. In order to
prevent premature interaction of the components prior to use on a
wound, for example during ethylene oxide sterilisation protocols,
these components can be physically separated. This physical
separation is temporary. A suitable mechanism of separation
includes encapsulating at least one of the components in a
resorbable coating, spacing the components in the fabric, or
otherwise spacing them within the layer. In FIG. 30A, the soluble
composition 260 is shown as being encapsulated in a resorbable
coating. In alternative embodiments, the pH indicator 280 is
encapsulated in a resorbable coating. In further alternative
embodiments, both the soluble composition 260 and the pH indicator
280 are encapsulated in a resorbable coating. Suitable resorbable
coatings are readily apparent to persons skilled in the art. As
illustrated in FIG. 30B, when wound exudate 310 migrates into the
device, the resorbable coating dissolves, causing the wound exudate
to dissolve the soluble composition 260, thereby releasing the
hydrogen or hydroxide ions into the wound exudate. The wound
exudate loaded with hydrogen or hydroxide ions interacts with the
pH indicator to cause a change in the colour of the pH indicator
from a first colour to a second colour. This colour change is
indicative that wound exudate has contacted the soluble composition
within the device 300.
[0336] FIG. 31A illustrates a device/wound dressing composite 410
having a device 400 for indicating the wound exudate loading of the
wound dressing combined with a conventional wound dressing. The
device 400 can be one of the embodiments of the device 100, 200 or
300 as described above and as illustrated in FIG. 28A, 29A or 30A,
or a variant thereof. The wound dressing comprises an absorbent
layer 420 which has a wound facing surface 440 and an opposing
non-wound facing surface 460. The device 400 is placed near or
adjacent to the opposing non-wound facing surface 460 of the
absorbent layer 420. The device has a first colour. A barrier layer
480 is used to cover the device to provide additional protection to
the wound dressing. Preferably, this barrier layer is made of a
material which permits the colour of the pH indicator to be visible
therethrough. For example, the barrier layer is made of a
substantially transparent material. As illustrated in FIG. 31B,
when wound exudate (as indicated by the arrows) migrates through
the absorbent layer 420 and reaches the device 400 it causes the
dissolution of a soluble composition and the consequent release of
hydrogen or hydroxide tons into the wound exudate. The interaction
of the wound exudate, loaded with the hydrogen or hydroxide ions,
with a coloured pH indicator results in a change in the colour of
the pH indicator from a first colour to a second colour. This
change to a second colour indicates to the patient or clinician
that the wound dressing is saturated at the region of the dressing
where the device is located, which, in this embodiment, is at the
opposing non-wound facing surface 460 of the absorbent layer.
[0337] An example method for fabricating a specific embodiment of
the structure illustrated in FIGS. 29A and 29B is outlined
below:
[0338] In a first step, a first layer is prepared by applying a
solution of universal indicator, diluted by 50% with ethanol, to a
piece of Whatman No. 1 filter paper (2 cm.times.2 cm)
(SigmaAldrich) until the paper is saturated. The paper is
oven-dried overnight at about 40.degree. C.
[0339] In a second step, a second layer is prepared by applying a
solution of a 2% solution of aqueous sodium carbonate to a second
piece of Whatman No. 1 filter paper (2 cm.times.2 cm)
(Sigma-Aldrich) until the paper is saturated. The paper is
oven-dried overnight at about 40.degree. c.
[0340] In a third step, a three-layered composite is prepared. The
upper layer is the first layer, as formed in step 1. The lower
layer is the second layer, as formed in step 2. A third, nontreated
piece of filter paper is sandwiched between the upper and lower
layers to provide a spacer layer. This spacer layer ensures that
the sodium carbonate and universal indicator are physically
separated, and thereby prevents any soluble sodium carbonate
(formed during ethylene oxide sterilisation process) from
prematurely interacting with the universal indicator. The three
layers are held together by a porous adhesive, the pores permitting
migration of wound exudate.
[0341] In certain embodiments, the filter paper which functions as
a spacer layer is replaced with a 3-D spacer layer, for example,
the spacer layer utilised within the PICO product (Smith &
Nephew).
[0342] An example method for fabricating a specific embodiment of
the structure illustrated in FIGS. 31A and 31B is outlined
below:
[0343] In a first step, a three-layered composite device as
described above in relation to FIGS. 29A and 29B is prepared. The
lower layer, which is impregnated with the sodium carbonate, is
adhered to the upper surface of an absorbent layer. An adhesive
barrier film is applied to the upper surface of the upper layer,
the upper layer being impregnated with universal indicator.
[0344] The devices described herein can be manufactured as a
separate element to a wound dressing and combined with a
conventional wound dressing by the clinician. Alternatively, the
devices can be incorporated into a wound dressing at the point of
manufacture. In either case, the devices can be located at
different regions of the wound dressing to suit the needs of a
particular clinical requirement. As illustrated in FIG. 32A, the
device 520 forms an annular ring which extends from and around a
peripheral edge of a wound dressing 510. Upon contact with wound
exudate, which migrates to the peripheral edge of the device, the
device changes from a first colour to a second colour. Dependent
upon the positioning of this device, the patient or clinician is
informed, by means of a colour change, that the layer of the
dressing from which the device extends is loaded with wound
exudate.
[0345] There is described herein a device for indicating wound
exudate loading within a wound dressing. This device comprises a
first composition which transforms from a first state to a second
state and a second composition which dissolves upon contact with
the wound exudate and which forces the transformation of the first
composition from the first state to the second state upon contact
therewith. The appearance of the second state is indicative of the
level of wound exudate loading and the patient and/or clinician can
make an informed decision as to whether to change the dressing. In
the embodiments of the device described above, the first
composition is a pH indicator which displays a colour that
correlates with a pH. The first state is a first colour and the
second state is a second colour. In the embodiment of the device
described above, the second composition is a soluble composition
which releases hydrogen or hydroxide ions when it dissolves upon
contact with wound exudate. It is contemplated that within the
scope of this application alternative compositions can be utilised
which interact by different mechanisms to those described above.
The underlying principle is that the second composition is altered
by contact with wound exudate and that this altered second
composition causes a transformation of the first composition from a
first state to a second state. This second state is perceivable to
the patient and/or clinician and is indicative of the moisture
loading of the wound dressing.
[0346] In certain embodiments, the first composition is potassium
thiocyanate and the second composition is a soluble iron (III)
compound, for example, iron (III) sulphate. The first state is a
first colour and the second state is a second colour. The first
state of the potassium thiocyanate is colourless. Upon contact with
wound exudate, ions released from the soluble iron (III) compound
interact with the potassium thiocyanate, forcing a transformation
to the second state, that is the second colour. The second colour
is red. This second state is perceivable to the patient and/or
clinician and is indicative of the moisture loading of the wound
dressing.
DETAILED DESCRIPTION SECTION 4
[0347] To provide an understanding of the devices and methods
describe herein, certain illustrative embodiments will now be
described. For the purpose of clarity and illustration, the wound
dressings herein are described as having a coloured moisture
indicator. However, other moisture indicators that are non-colour
based can be used. Such other additions and modifications will not
depart from the scope hereof.
[0348] Reference numbers cited in Section 4 correspond to the
reference numbers used in FIGS. 33-37.
[0349] FIGS. 33A and 33B depict a wound dressing 100 having a wound
contacting layer 102 with a wound-facing or wound-contacting
surface 104. FIG. 33B depicts the wound dressing in situ on a
wound.
[0350] The dressing further includes an absorbent element 106,
which can be any material that provides the desired level of
absorption of the wound exudate 108. For example, the absorbent
element 106 can be a porous foam, particularly a polyurethane foam.
Alternatively, the absorbent element 106 can be hydrocolloid-based,
hydrogel-based, or alginate-based, or any other suitable absorbent
material, or any combination thereof.
[0351] The dressing comprises a moisture indicator 110. In
embodiments the moisture indicator is a coloured moisture
indicator. The indicator does not necessarily change colour upon
contact with wound exudate, but its visibility to the user is
altered so that it becomes either visible or invisible. This
contrasts with certain moisture indicators found in the existing
wound dressing which rely on a colour-change of the indicator
itself which is often imperceptible. The coloured moisture
indicators of the present application can be advantageous to the
user as they provide a discernable visual indication of the
moisture levels within the dressing. The colour of the indicator is
preferably selected so that it is unambiguously discernable against
the other parts of the dressing.
[0352] The coloured moisture indicator can be a porous coloured
substrate, for example a piece of coloured paper through which the
wound exudate can diffuse. Alternatively, the coloured moisture
indicator can be a water-soluble coloured dye which, upon
solubilisation by the wound exudate, diffuses through the
dressing.
[0353] The visibility of the moisture indicator 110 is altered as a
result of the physical transformation of a first material 112. The
first material acts as a mask, which either conceals or exposes the
moisture indicator, based on the type of physical transformation.
In certain embodiments the physical transformation affects a change
in the appearance of the first material, preferably without
changing the composition of the indicator. In certain embodiments
the physical transformation is a transformation from a dry material
to a wet material, from a solid material to a gel or gel-like
material and vice versa, or from a substantially transparent or
translucent material to a substantially opaque material and vice
versa or a combination thereof. The physical transformation
produces a transformed region 114 within the first material 112 and
it is this region which affects the visibility of the moisture
indicator. In some embodiments, the transformed region 114
functions as a mask which conceals the moisture indicator before
the region is physically transformed. Once the region is
transformed the mask is disrupted and the moisture indicator
becomes visible. In alternative embodiments, the transformed region
114 functions as a mask which conceals the moisture indicator after
the region is physically transformed. The transformation of the
region results in the formation of the mask and the moisture
indicator becomes invisible.
[0354] As shown in FIGS. 34A and 34B, the wound dressing comprises
a water-soluble coloured moisture indicator for indicating the
saturation levels of the dressing. FIG. 34A shows a side
cross-sectional view of a wound dressing 200 having a wound
contacting layer 202, the lower surface of which is a wound-facing
surface 204. The dressing also comprises an absorbent element 206.
A first material 212 is located on or adjacent to the surface of
the absorbent element which is opposed to the wound-facing surface
204. The first material 212 is of a first colour, preferably white,
although it is envisaged that other colours could be utilized. A
water-soluble coloured moisture indicator 210, having a second
colour, is provided on or within the absorbent layer 206. This
second colour is selected to be a contrasting colour to the first
colour. For example, if the first colour is white, the second
colour is selected to be not white. Suitable water-soluble coloured
moisture indicators, for example water-soluble dyes, for use in
wound dressings are readily apparent to persons skilled in the art.
The absorbent layer has opposing peripheral edges 214 and 216 and
although FIGS. 34A and 34B depict the water-soluble coloured
moisture indicator 210 as a mark which is centrally located in the
absorbent layer, it is envisaged that the indicator 210 can be
located anywhere between the opposing peripheral edges and, if
desired, additional indicators (of the same or of a different
colour) can be provided at different locations between the
peripheral edges in order to provide an indication of the
horizontal spread of wound exudate within the absorbent layer. For
example, as illustrated, an indicator 211 based on a water-soluble
dye of the same colour as indicator 210 is provided nearer to an
outer peripheral edge.
[0355] FIG. 34B, illustrates two stages of wound dressing
saturation and the temporal relationship between the solubilisation
and subsequent visualisation of the marks 210 and 211. In the upper
panels (A) the wound dressing is dry and, from the plan view, it
can be seen that the first material is substantially white. This
informs the user, for example, the patient or care provider, that
the absorbent layer has not been saturated and that the wound
dressing does not require changing. As illustrated in the lower
panels (B), when wound exudate 208 has saturated the absorbent
layer 206, the indicators 210 and 211 become solubilised and
diffuse through the first material 212 and become visible as a
contrasting coloured mark on the upper surface of the first
material. This indicates to the user that the dressing needs to be
changed. In some embodiments, the first material 212 forms the
uppermost surface of the wound dressing, which is often referred to
as the backing layer. In alternative embodiments, the first
material 212 is covered by additional layers of the dressing,
although such layers are preferably transparent, such that the
first material is visible therethrough and the appearance of the
coloured mark(s) on the first material is not hampered.
[0356] As described above, in some embodiments the coloured
moisture indicator appears on the upper surface of the first
material, this surface being white or other light colour. The
coloured moisture indicator is of a contrasting colour to white, so
that the apparent "white to colour" transition provides an
unambiguous visual indication as to dressing saturation.
[0357] Methods for fabricating wound dressing products are also
contemplated. An example includes the following steps for making
the dressing illustrated in FIG. 34, as outlined below:
[0358] In a first step, a first coating (filler layer) is applied
to the upper side of a sheet of conventional copy paper (-80 GSM).
Coating I (-100 GSM) may be a dispersion of talc, or other
transparent filler, in a water-soluble binder such as
carboxymethylcellulose. The dispersion is preferably formulated
with a high pigment/binder ratio to provide satisfactory porosity
The function of this coating is to mask traces of the underlying
coloured moisture indicator.
[0359] In a second step, the lower side of the paper is coated with
a second coating (barrier layer). An example barrier layer is
coating 2 (-5-10 GSM), a thin film of polyvinyl alcohol (PVOH). The
function of this coating is to seal the paper, in order to impair
or prevent the low viscosity ink from diffusing through the paper
upon its application.
[0360] In a third step, ink is applied to the surface of the second
coating, by inkJet or similar deposition method. An example ink is
a low-viscosity ink, based on a water-soluble dye.
[0361] The response time of the indicator is typically about 10
minutes, but the response time may vary as a function of the paper
porosity, thickness of the barrier film and/or the solubility of
the dye. In certain applications although the coated paper may
react with liquid water, it is not affected by the high levels of
humidity associated with sterilization of the wound dressing (e.g
by ethylene oxide).
[0362] Methods of fabricating alternative specific embodiments of
the structure illustrated in FIG. 34 include;
[0363] In a first step, the filler layer is applied to the lower
surface of the paper so that it is sandwiched between the paper and
the barrier layer.
[0364] In a second step, a dispersion of aluminium hydroxide is
used to form the filler layer. This compound may cause the mobile
ink to instantly gel, so preventing if from diffusing before it is
contacted by wound exudate.
[0365] In a third step, titanium dioxide is added to the filler
dispersion to emphasise the contrast of colour against a white
background without significantly reducing the colour strength.
[0366] In certain embodiments, the wound dressing comprises a
coloured moisture indicator which gradually becomes invisible as
the wound dressing becomes saturated. Such a mechanism is shown in
FIGS. 35A and 35B.
[0367] FIG. 35A shows a side cross-sectional view of a wound
dressing 300 having a wound contacting layer 302, the lower surface
of which is a wound-facing surface 304. The dressing also comprises
an absorbent element 306. Located on the surface of the absorbent
element which is opposed to the wound-facing surface 304 is a first
material 312 which is made of a material which, upon hydration,
transforms from a transparent material to an opaque material having
a first colour. Many polymers, such as solutions of polyvinyl
acetate (PVA), shellac and latex rubber form transparent films when
the carrier solvent evaporates. When the film subsequently comes
into contact with water, the polymer re-hydrates to form a white,
opaque film. When PYA is bought into contact with water, a
relatively high level of opacity develops within a short length of
time. This can provide a real-time indication of wound dressing
saturation. As illustrated, a coloured moisture indicator 310
having a second colour lies between the absorbent layer and the
first material. The second colour is selected to contrast with the
colour of the opaque film. For example, if a PVA film is used,
which forms a white opaque film upon hydration, the second colour
is selected to be non-white and is desirably selected to be a
colour that readily contrasts with white. Whilst the material
selected for the first material is preferably able to physically
transform from a transparent material to an opaque material, it is
not a requirement that the first material is colourless i.e
clear.
[0368] In some embodiments, the coloured moisture indicator 310 is
in close contact with, for example, overlies the absorbent layer.
In some embodiments the coloured moisture indicator 310 contacts
only part of the absorbent layer 306, for example, the central part
or a peripheral part For example, the coloured moisture indicator
310 may form a peripheral edge upon the upper surface of the
absorbent layer 306, and the subsequent visibility of the coloured
indicator indicates full saturation of the dressing to the
peripheral edges. In certain embodiments the coloured indicator is
a porous coloured substrate, for example a coloured paper. In other
embodiments a coloured mark/graphic (e.g a logo) is applied
directly onto the upper surface of the absorbent layer. In some
embodiments of the invention the first material 312 forms the
uppermost surface of the wound dressing, which is often referred to
as the backing layer In alternative embodiments, the first material
312 is covered by additional layers of the dressing, although such
layers are transparent, such that the first material is visible
there through. In certain embodiments the physical transformation
is reversible. For example, upon hydration the PVA film forms a
white opaque film, but if the wound starts to dry out, which is
indicative of suboptimal healing, the opaque film reverts to a
transparent film and the coloured moisture indicator becomes
visible again.
[0369] FIG. 35B illustrates two stages of wound dressing saturation
and the temporal relationship between the wound dressing saturation
and the visibility of the coloured moisture indicator 310. In the
upper panels (A) the wound dressing is dry and from the plan view
of the dressing it can be seen that the first material 312 is
completely transparent and the coloured moisture indicator 310 is
visible through the first material 310. This informs the user, for
example the patient or care provider, that the absorbent layer has
not been saturated and that the wound dressing does not require
changing. As illustrated in the lower panels (B), when the wound
exudate saturates the absorbent layer 306, it permeates through the
coloured moisture indicator 310 and contacts the first material
312. This contact hydrates the first material 312 and causes the
development of an emulsion, turning the transparent first material
312 opaque. The opaqueness conceals the coloured moisture indicator
310, for example a coloured substrate or a coloured mark/graphic
(e.g a logo) which is associated with the absorbent layer. When a
predetermined amount of the coloured moisture indicator has become
concealed, it indicates that it is time to change the dressing. A
reference guide can be provided which informs the user of the
relationship between the visibility of the coloured moisture
indicator and the level of saturation of the dressing, in order
that an informed decision about the need to change the dressing can
be taken.
[0370] In certain embodiments, the wound dressing is a
superabsorbent dressing utilized in a Negative Pressure Wound
Therapy (NPWT) System, for example the dressing of the PICO.RTM.
Single Use Negative Pressure Wound Therapy System (Smith &
Nephew Inc.). Such dressings are provided with a port into which a
vacuum tube is secured. It could be advantageous for the coloured
moisture indicator to be associated with this port, with the
concealment of the coloured moisture indicator being indicative of
a fully saturated dressing, which should be removed.
[0371] As described above, in some embodiments the coloured
moisture indicator becomes concealed by the development of an
opaque film. In embodiments in which the opaque film is white in
colour, the coloured moisture indicator may be a contrasting colour
to white, so the apparent "colour to white" transition provides an
unambiguous visual indication as to dressing saturation.
[0372] An Example method for fabricating a specific embodiment of
the structure illustrated in FIG. 35 is outlined below:
[0373] In a first step, a film of PYA emulsion is deposited onto a
thin (e.g 35 micron) a polyester/plastic film, for example
Mylar.RTM. (Dupont). This prevents the reticulation of the
converted PYA. The PYA is preferably a 50% aqueous emulsion, for
example Unibond (Henkle) or Cementone Rendabond (Bostik).
[0374] In a second step, the wet film is oven-dried (e.g to about
70 degrees Celsius) to provide a transparent PYA film of about 100
microns thick. The PYA/Mylar laminate is then bonded to an
appropriately coloured material (e.g a, 2-ply paper tissue (35
GSM)) using an adhesive such as polyvinyl alcohol or KS adhesive
(Smith & Nephew, Inc).
[0375] In a third step, the laminate prepared in step 2 is adhered
to the upper surface of the absorbent layer in a wound
dressing.
[0376] Although PVA film may react with liquid water, it is not
necessarily affected by the high levels of humidity associated with
the ethylene oxide sterilization of the wound dressing.
[0377] Methods of fabricating alternative embodiments of the
structure illustrated in FIG. 35 include:
[0378] In a first step, the PVA/Mylar layer is bonded directly onto
an appropriate coloured piece of fusible interlining, for example
based on non-woven rayon.
[0379] In a second step, the Mylar film is omitted and instead the
layer of PVA emulsion is screen printed, or otherwise directly
deposited, onto the porous coloured substrate.
[0380] In a third step, the porous coloured tissue paper is omitted
and the coloured mark/graphic (e.g a logo) is directly applied onto
the upper surface of the absorbent layer of the dressing.
[0381] In a fourth step, the use of an adhesive is omitted by
instead hot bonding the PVA/Mylar laminate onto the porous coloured
substrate.
[0382] In a fifth step, the porous coloured substrate is omitted
and instead a pattern (e.g a chequerboard) or other graphic element
(e.g a logo) is directly applied onto the uppermost transparent
film (e.g PYA/Mylar laminate) such that the pattern can be
displayed as a more distinctive change signal.
[0383] In certain embodiments the wound dressing comprises a
coloured moisture indicator which gradually becomes visible as the
wound dressing becomes saturated. Such a mechanism is shown in
FIGS. 36A and 36B.
[0384] FIG. 36A shows a side cross-sectional view of a wound
dressing 400 having a wound contacting layer 402, the lower surface
of which is the wound-facing surface 404. The dressing also
comprises an absorbent element 406. Located on the surface of the
absorbent element which is opposed to the wound-facing surface 404
is a first material 412, made of a material which upon hydration
transforms from being opaque to a transparent/translucent. A
suitable material is a water-soluble paper, which is preferably a
polyvinyl alcohol-based. The water-soluble paper has a fibrous
structure which upon hydration transforms and disintegrates into a
transparent/translucent gel or gel-like material. There are many
types of suitable water soluble papers available, including, for
example, water-soluble papers based on plant materials such as
rice, cornflour and cellulose or based on synthetic polymers, such
as polyvinyl alcohol, the base for the Aquasol (Aquasol Corp)
range. The water-soluble paper is preferably white. As illustrated,
a coloured moisture indicator 410 having a second colour lies
between the absorbent layer and the first material. The second
colour is selected to contrast with the colour of the opaque
water-soluble paper. For example, if the non-hydrated form of the
water-soluble paper is white, then the second colour is selected to
be non-white and is preferably a colour that readily contrasts with
white. In some embodiments, the coloured moisture indicator 410 is
in close contact with the absorbent layer, for example, it may
overly the absorbent layer. In some embodiments, the coloured
moisture indicator 410 contacts only part of the absorbent layer,
for example, the central part or a peripheral part. The coloured
moisture indicator 410 may form a peripheral edge upon the upper
surface of the absorbent layer, such that the subsequent visibility
of the coloured indicator indicates of full saturation of the
dressing to the peripheral edges. When the practitioner sees that
the indication he or she may decide to change the dressing. In
certain embodiments the coloured indicator is a porous coloured
substrate, for example a coloured paper. In other embodiments a
coloured mark/graphic (e.g a logo) is applied directly onto the
upper surface of the absorbent layer. In some embodiments, the
first material 412 forms the uppermost surface of the wound
dressing, which is often referred to as the backing layer. In
alternative embodiments, the first material 412 is covered by
additional layers of the dressing, although such layers are
transparent, such that the first material is visible there through.
In some embodiments, an additional coloured element is disposed
between the first material 412 and the coloured moisture indicator
410. This additional coloured element has a third colour, which is
of a contrasting colour to the second colour. In this embodiment,
the first material 412 and the additional coloured element do not
necessarily extend completely over the coloured moisture indicator
410, such that when the first material 412 becomes hydrated and
dissolves, the third colour becomes visible against the coloured
moisture indicator. In certain embodiments, the wound dressing is a
superabsorbent dressing utilized in a Negative Pressure Wound
Therapy (NPWT) System, for example the dressing of the PICO.RTM.
Single Use Negative Pressure Wound Therapy System (Smith &
Nephew Inc,). Such dressings are provided with a port into which a
vacuum tube is attached to. If the coloured moisture indicator is
associated with this port, the exposure of the coloured moisture
indicator may indicate a fully saturated dressing, which should be
removed.
[0385] FIG. 36B illustrates two stages of wound dressing saturation
and illustrates the temporal relationship between the wound
dressing saturation and the visibility of a coloured moisture
indicator 408. In the upper panels (A) the wound dressing is dry
and from the plan view of the dressing it can be seen that the
first material 412 is completely opaque and the coloured moisture
indicator 410 is invisible through the backing layer. This informs
the user, for example the patient or care provider, that the
absorbent layer has not been saturated and that the wound dressing
does not require changing. As illustrated in the lower panels (B),
when the wound exudate 408 has saturated the absorbent layer 406,
it permeates through the coloured substrate 410 and contacts the
first material 412. This contact hydrates the first material 412,
causing the development of a transparent/translucent gel. This
transparency exposes the coloured moisture indicator 410 beneath.
When a predetermined amount of the second colour has become exposed
it is time to change the dressing. A reference guide can be
provided which informs the user of the relationship between the
visibility of the coloured moisture indicator and the level of
saturation of the dressing, in order that an informed decision
about the need to change the dressing can be made.
[0386] As described above, in some embodiments the coloured
moisture indicator becomes exposed by the development of a
transparent/translucent film. The coloured moisture indicator may
be a contrasting colour to white, so the apparent "white to colour"
transition, provides an unambiguous visual indication as to
dressing saturation.
[0387] An Example method for fabricating an embodiment of the
structure illustrated in FIG. 36 is outlined below:
[0388] In a first step, a water-soluble paper (.about.60 GSM) is
bonded to an appropriately coloured material (e.g. a 2-ply, paper
tissue (.about.35 GSM)) using an adhesive such as polyvinyl alcohol
or KS adhesive (Smith & Nephew, Inc), to form a laminate.
[0389] In a second step, the laminate prepared in Step I is adhered
to the upper surface of an absorbent layer in a wound dressing.
[0390] Although the laminate reacts with liquid water, it not
necessarily affected by the high levels of humidity associated with
sterilization of the wound dressing (e.g by ethylene oxide).
[0391] Methods of fabricating alternative embodiments of the
structure illustrated in FIG. 36 include:
[0392] In a first step, the water-soluble paper is bonded directly
onto an appropriate coloured piece of fusible interlining, for
example based on non-woven rayon.
[0393] In a second step, the use of an adhesive is omitted and
instead an adherent water-soluble paper is used.
[0394] In certain embodiments, the wound dressing includes a
coloured moisture indicator associated with each layer of the
dressing, such that the user is visually informed of the vertical
progression of the wound exudate and therefore the saturation state
of each dressing layers. An example of this design of dressing is
illustrated in FIGS. 37A and 37B in which the wound dressing
comprises a water-soluble coloured moisture indicator associated
with each layer of the dressing.
[0395] FIG. 37A shows a side cross-sectional view of a wound
dressing 500 having a wound contacting layer 502, the lower surface
of which is a wound-facing surface 504. A first material 512 is
located on or adjacent to the surface of the wound contacting layer
502 which is opposed to the wound-facing surface 204. The wound
contacting layer 502 and the first material 512 are preferably of
the same diameter. The dressing also comprises an absorbent element
506. A second material 516 is located on or adjacent to the surface
of the absorbent element 506 which is opposed to the wound-facing
surface 504. The absorbent element 506 and the second material 516
are preferably of the same diameter, with this diameter being
selected to be smaller than the diameter of the wound contacting
layer 502 and the first material 512. As a result of this
selection, a border or flange of the wound contacting layer
502/first material 512 extends outwardly from below the perimeter
edges of the absorbent element 506/second material 516. The first
material 512 and the second material 516 are of a first colour,
preferably white, although it is envisaged that other colours could
be utilized. A water-soluble coloured moisture indicator 510,
having a second colour, is provided on or within the wound
contacting layer 502. A water-soluble coloured moisture indicator
511, having a third colour, is provided on or within the absorbent
layer 506. The second and third colours are selected to be a
contrasting colour to the first colour. For example, if the first
colour is white, the second and third colours are selected to be
not white. Suitable water-soluble coloured moisture indicators, for
example water-soluble dyes, for use in wound dressings are readily
apparent to persons skilled in the art.
[0396] FIG. 37B, illustrates two stages of wound dressing
saturation and the temporal relationship between the solubilisation
and subsequent visualisation of the marks 510 and 511. In the upper
panels (A) the wound dressing is dry and, from the plan view, it
can be seen that the first material and the second material are
substantially white. This informs the user, for example, the
patient or care provider, that neither the wound contacting layer,
nor the absorbent layer, has been saturated by wound exudate. As
illustrated in the middle panels (B), when wound exudate 508 has
saturated the wound contacting layer 502 the indicator 510 is
solubilised and diffuses through the first material 512 and becomes
visible as a contrasting coloured mark on the upper surface of the
first material 512. In some embodiments, the first material 512
forms the uppermost surface of the wound contacting layer. The
visibility of the indicator 510 indicates to the user that the
wound contacting layer 502 has become saturated. This may not
necessarily indicate that a dressing change is required, but it may
be a useful indication to the user of the rate of wound exudate
secretion from the wound. As illustrated in the lower panels (C),
when wound exudate 508 has saturated the absorbent layer 506, the
indicator 511 is solubilised and diffuses through the second
material 516 to become visible as a contrasting coloured mark on
the upper surface of the second material 516. In some embodiments,
the second material 516 forms the uppermost surface of the wound
contacting layer. In alternative embodiments, the second material
516 is covered by additional layers of the dressing, although such
layers are preferably transparent, such that the second material is
visible there through and the appearance of the coloured mark(s) on
the second material is not hampered. The visibility of the
indicator 511 indicates to the user that the absorbent layer of the
dressing has become saturated and that the dressing may require
changing.
[0397] As described in relation to FIGS. 37A and 37B, in certain
embodiments, the wound dressing includes a coloured moisture
indicator associated with each layer of the dressing, this enables
the user to be visually informed as each layer of the dressing
becomes saturated by the vertical progression of the wound exudate.
Whilst FIGS. 37A and 37B disclose the use of water-soluble dyes as
the moisture indicator, in alternative embodiments, it is envisaged
that the moisture indicators disclosed in reference to FIGS. 35 and
36 may be utilized within a similar design of dressing, as
described below.
[0398] In embodiments, the first and second materials 512, 516 that
are associated with the wound contacting layer 502 and the
absorbent layer 506, respectively, are made of a material which,
upon hydration, transforms from a transparent material to an opaque
material having a first colour, as disclosed above in reference to
FIG. 35. The first colour is preferably white. A first coloured
moisture indicator, for example a coloured substrate or a coloured
mark/graphic (e.g a logo), is placed between the wound contacting
layer and the first material. The first coloured moisture indicator
is of a colour that is contrasting to white. A second coloured
moisture indicator, for example a coloured substrate or a coloured
mark/graphic (e.g a logo), is placed between the absorbent layer
and the second material. The second coloured moisture indicator is
also of a colour that is contrasting to white and further is
discernable from the colour of the first coloured moisture
indicator. Within the dry dressing, both the first and second
coloured moisture indicators are visible to the user. When the
wound contacting layer becomes saturated the first material becomes
hydrated and turns opaque, concealing the first coloured moisture
indicator. When the absorbent layer becomes saturated the second
material becomes hydrated and turns opaque, concealing the second
coloured moisture indicator. The fully hydrated dressing will
appear white to the user.
[0399] In embodiments, the first and second materials 512, 516 that
are associated with the wound contacting layer 502 and the
absorbent layer 506, respectively, are made of a material which,
upon hydration, transforms from an opaque material having a first
colour to a transparent material, as disclosed above in reference
to FIG. 35. The first colour is preferably white. A first coloured
moisture indicator, for example a coloured substrate or a coloured
mark/graphic (e.g a logo), is placed between the wound contacting
layer and the first material. The first coloured moisture indicator
is of a colour that is contrasting to white. A second coloured
moisture indicator, for example a coloured substrate or a coloured
mark/graphic (e.g a logo), is placed between the absorbent layer
and the second material. The second coloured moisture indicator is
also of a colour that is contrasting to white and further is
discernable from the colour of the first coloured moisture
indicator. Within the dry dressing, both the first and second
coloured moisture indicators are invisible to the user. When the
wound contacting layer becomes saturated the first material becomes
hydrated and turns transparent, exposing the first coloured
moisture indicator. When the absorbent layer becomes saturated the
second material becomes hydrated and turns transparent, exposing
the second coloured moisture indicator. The fully hydrated dressing
will have a central first colour and a ring of a second colour
extending thereabouts.
DETAILED DESCRIPTION SECTION 5
[0400] Reference numbers cited in Section 5 correspond to the
reference numbers used in FIGS. 38-50.
[0401] An automated wound dressing image processing system provides
a physician or patient with an effective and reliance approach to
monitoring a wound, such as when negative pressure wound therapy is
applied to the wound. FIG. 38 shows a wound monitoring method 100
that informs the patient or physician of wound status indicated by
a color-coded pH indicator wound dressing. The method 100 automates
the determination of bandage color to provide accurate readings of
wound pH. Rather than relying on a user's judgment in discerning
the color of a wound pH indicator and relating the discerned color
to a pH scale, the method 100 allows the user to capture a digital
image of the wound dressing and applies image processing techniques
to determine the indicated pH. The resulting monitoring method thus
improves the reliability of pH readings that may be used to apply
or change the treatment regimen applied to the healing wound. The
illustrated method can be implemented by a user device alone or in
combination with one or more computing devices, such as a
server.
[0402] The wound monitoring method 100 begins when an image of a
color-coded wound pH indicator is captured at step 102. The
indicator is disposed on a patient's wound dressing and includes
one or more pH-sensitive dyes or compounds that change color as the
pH of the wound to which the dressing is applied changes. For
example, a particular dye may exhibit a spectrum of colors, from
lighter yellow and orange colors to darker red or purple colors,
when exposed to different pH values over the range from 0 to 14.
Particular dyes and compounds disposed on such bandages may vary,
and any suitable wound pH indicators, exhibiting any suitable known
spectrum of colors, may be employed in the systems and methods of
the present disclosure.
[0403] The image captured at step 102 of method 100 is taken on a
user device, for example, by a physician during a patient visit or
by the patient away from the doctor's office. With the advancements
in smartphones and mobile technology, the range of user devices
suitable for use in method 100 is quite broad. Any user device
having a camera for image capture and circuitry either to process
the image locally or transmit the image for remote processing is
suitable for the method. For example, smartphones, tablet
computers, laptop computers, digital cameras, web-enabled cameras,
or any other user devices with image capturing and processing or
communication circuitry could be used at step 102. The portability
of many of these devices provides an advantage by allowing the user
to capture the image at step 102 in virtually any location with the
user device. Thus, the method 100 provides a patient with wound
monitoring and feedback without requiring constant check-ups with a
doctor or visits to the doctor's office to obtain a reading.
[0404] The image captured at step 102 is processed at step 104 to
determine the pH of the wound that is indicated by the color of the
wound dressing. In some embodiments, the image is captured on a
mobile device, for example using an app on a smartphone, and the
mobile device itself performs the processing at step 104 to
calculate the indicated pH. In other embodiments, the user device
transmits the captured image to a remote location, for example to a
server, where the image is processed to calculate the pH. The
server may then transmit the calculated pH back to the user device
for display and use in evaluating the wound status. The server, the
user device, or both can also store a record of the pH readings for
trend and progress analyses.
[0405] The image processing at step 104 automatically characterizes
the color of the wound dressing in the captured image. This may be
done, for example, by determining where the color of the dressing
lies in the RGB color model (or any other suitable color model such
as CMYK, Lab colour space, and the like). The processing applied to
the image determines the red, blue, and green components of the
overall dressing color and uses the relative presence of the three
colors to characterize the color. The RGB characterization values
are then compared to standardized pH RGB values to calculate the pH
indicated by the wound dressing. Further details on this processing
and pH calculation are discussed below, for example in relation to
FIG. 39.
[0406] After the pH of the wound is determined at step 104, the
calculated pH value is relayed to the patient or physician at step
106. The pH is displayed either on the user device used to capture
the image or on another device in communication with the user
device or with a server in the system. In addition to the
calculated value, the pH may be displayed at step 106 with one or
more accessory features, such as a graph showing past pH readings
for the patient, a list of pH readings, an indication of wound
health based on the reading, a suggested mode of treatment for the
wound, or any other suitable information for the patient or
physician. In addition, the display may provide the user with
various options for storing or identifying the pH reading. For
example, step 106 may include displaying an option to the user to
accept or reject the pH reading, and may prompt the user to capture
a new image if the pH reading is rejected. The display may also
provide the user with an option to identify the patient for record
keeping, where the calculated pH value is associated with either an
already stored patient or a newly identified patient for tracking
the progress of the wound. In some embodiments, the patient may be
automatically identified by a barcode or a QR code on the bandage
in the image.
[0407] The method 100 provides prompt feedback and an accurate pH
reading, by implementing automated image processing and analysis at
step 104. The color extraction and pH calculation performed at step
104 can provide improved accuracy in the pH reading, and thus in
the treatment decisions that are based on the pH. The processing
applied to the image first automates the determination of wound
dressing color, and then applies processing to provide a pH read
out from the detected color.
[0408] FIG. 39 shows a method 110 for processing a wound dressing
image to provide a patient or physician with a pH readout, which
may be the method performed at step 104 in FIG. 38. The illustrated
method can be implemented by a user device alone or in combination
with one or more computing devices, such as a server. After an
image is captured or received, system implementing the method 110
defines or identifies a region of interest in the wound dressing
captured in the image at step 112. The region of interest defines
the area of the image that is determined to be an adequate
representation of the wound dressing for color and pH
determinations. The region may have any suitable shape and size,
for example a circle or a square having a radius or area defined by
a predetermined number of pixels. In some embodiments, the region
is defined as the pixels that form a particular shape of a
particular size around a determined center point of the wound
dressing image. In such embodiments, the center of the dressing
image is first defined at step 112, and the region of interest is
defined based on the shape and size settings around the defined
center point. A circular region around the center point can be
defined having a radius of any suitable number of pixels, for
example five pixels, ten pixels, twenty pixels, fifty pixels, one
hundred pixels, or any other suitable radius. The shape and size of
the region may be an oval, rectangle, square, triangle, trapezoid,
or any suitable shape of a suitable size. The shape and size of the
region may also be defined based on the resolution settings of the
camera used to capture the image, or on the size of the captured
image. In certain implementations, the method 110 defines or
identifies multiple regions of interest. Any suitable number and
dimensions of the multiple regions can be selected. For example,
the multiple regions can be five circles as depicted in FIG. 47
(namely one circular region in the middle or the dressing
surrounded by four circular regions in each of the four corners of
the dressing).
[0409] When the region of interest for analysis has been defined, a
system implementing the method 110 characterizes the color of the
dressing, as determined from the region of interest, at step 114.
Each pixel lying within the defined region of interest is analyzed
to extract the RGB values for the pixel color from the image.
Particularly for cases in which the region of interest is larger,
there may be variation of the exact color of the wound dressing
over the pixels included in the region. Thus, it may be preferable
to define the region of interest large enough to capture pixels
that will provide an accurate representation of the dressing color.
Including too few pixels in the region may result in one pixel or
small area of the dressing, for example a pixel or area that is
artificially dark due to poor imaging, skewing the overall RGB
characterization and affecting the accuracy of the pH value
calculated from the characterization. If the region is defined
broadly enough, the extraction of RGB values at step 114 will
include enough accurate pixel readings to dilute the effect of any
artificial pixels or areas. Alternatively, a filter may be applied
to remove these artificially light or dark pixels from the
analysis. For example, individual pixels that exhibit RGB values
that lie a certain distance from the average RGB values of the
pixels in the region of interest may be designated as outliers and
removed from the analysis.
[0410] After the individual pixel RGB values within the region of
interest are extracted from the image, the values are averaged at
step 116 to determine the RGB value characterization for the
overall dressing in the image. By averaging the pixel values at
step 116, the method 110 provides an accurate automated reading of
the color of the dressing, as determined by the color or colors
present within the defined region of interest. The averaged RGB
values determined at step 116 are the values that are then used in
calculating a pH value indicated by the imaged wound dressing
indicator.
[0411] In order to provide accurate pH calculations from the values
determined at step 116, the method 110 includes performing color
determinations for calibration color squares. The calibration
colors can provide readings of standardized colors that are used to
normalize the dressing RGB values. This normalization can account
for variation in captured images, for example caused by variations
in the image capture device, positioning of the wound dressing,
lighting when the image is captured, type of wound dressing,
pH-sensitive dye included in the dressing, or other factors that
may affect captured dressing images. The calibration colors that
are analyzed may be included in the same image as the dressing
image, for example as a strip provided on the dressing itself or a
strip placed in this image window with the dressing, or may be
captured in a separate image under the same or similar conditions
as the dressing image. Providing the strip on the dressing itself
may be convenient for the user as a separate strip does not need to
be included in each image. Using a separate strip may also be
advantageous for reproducing, for example, for a doctor who uses
the same strip for all patients. The separate strip may also ensure
the color blocks do not become discolored from blood in the wound
under the bandage.
[0412] The calibration colors that are captured for normalization
exhibit the expected color of the wound dressing at a range of pH
values. The colors may be provided as a series of color blocks, for
example as three, five, seven, or more blocks, in a strip on the
wound dressing. The color blocks may show the expected colors at
set pH increments, for example at one or more of pH values 4.0,
5.0, 6.0, 7.0, 8.0, 9.0, intermediate values between those pH
values, or pH values above 9.0 or below 4.0. Whether these color
blocks are included as a color calibration strip on the wound
dressing or as a separate component by an image, the standardized
colors are processed beginning at step 118 of method 110 to
normalize the dressing RGB values determined at step 116 and reduce
the effect of image variation.
[0413] At step 118, similar to step 112 for the dressing, a region
of interest is defined for each calibration color block included in
the captured color calibration strip. As with the dressing, each
region of interest may be defined as a set shape of a set number of
pixels surrounding the center of the color block. The shape and
size of each color block region of interest may be the same as the
shape and size of the dressing region of interest, or may be a
different shape or size. For example, in an embodiment where the
color calibration strip is provided at the bottom of the wound
dressing, the color blocks may be smaller than the dressing area,
and the regions of interest may also be defined as smaller pixel
areas.
[0414] The defined region of interest in each color block is
analyzed at step 120 to extract RGB value characterizations of the
calibration colors. Though the colors in the strip may be the same
between different dressings or different images of the same
dressings, variations in lighting and image capture condition can
cause different RGB value determinations at step 120 between
readings. The purpose of the color calibration strip is to
identify, and correct for, this variation in readings of identical
colors between images. As with the dressing RGB values, the
individual pixel RGB values extracted for each color block at step
120 are averaged at step 122 to provide a single set of RGB values
for each standardized color block in the calibration strip.
[0415] After the individual calibration pixel RGB values are
averaged at step 122, the image has been processed to determine a
first set of RGB values that characterizes the dressing color and a
series of RGB value sets, one for each color block, each of which
characterizes a standardized color in the color calibration strip.
The dressing RGB values and the calibration RGB values are combined
at step 124, and a single pH value for the wound dressing is
calculated and provided to the user. While the exact processing
that is applied at step 124 may vary, an illustrative process is
shown visually in FIG. 40.
[0416] FIG. 40 depicts a process that treats each RGB value in an
extracted wound dressing RGB value set and three extracted
calibration RGB value sets as point locations in a
three-dimensional space represented by RGB axis 130. The
illustrated process can be implemented by a user device alone or in
combination with one or more computing devices, such as a server.
The dressing RGB value set is depicted as point 132, labeled
RGB.sub.sAMP, in the three-dimensional space. The three calibration
RGB value sets are depicted as points 134, 136, and 138, labeled
RGB.sub.CAL1, RGB.sub.CAL2, and RGB.sub.CAL3, respectively. While
three calibration RGB points are shown in FIG. 40 for illustration,
any suitable number of calibration points, corresponding to the
number of color blocks in the imaged color calibration strip, may
be used to determine pH value.
[0417] From the plotted points, the process determines the
distances between the dressing RGB point 132 and each of the
calibration RGB points 134 (d.sub.3), 136 (d.sub.1), and 138
(d.sub.2). These distances graphically represent the similarity
between the color of the wound dressing, as defined by the
RGB.sub.sAMP values, and each of the calibration colors,
represented by the RGB.sub.CAL values. A relatively small distance
between the dressing RGB values and a given set of calibration RGB
values indicates similarity between the dressing and particular
calibration color, while relatively larger distances indicate
different colors. For example, in FIG. 40, each of d.sub.1 and
d.sub.2 are shorter than distance d.sub.3. This indicates that the
color of the wound dressing from which the RGB.sub.sAMP values were
extracted is more similar to the color of the color blocks from
which the RGB.sub.CAL2 and RGB.sub.CAL3 values were extracted than
it is to the color of the color block from which the RGB.sub.CAL1
values were extracted.
[0418] Once all distances between the dressing RGB value and each
set of calibration RGB values are determined. The process selects
the two smallest determined distances to identify the two
calibration colors, and corresponding standardized pH values
associated with these two calibrated colors, that are most similar
to the dressing color and wound pH value. For example, in the
visualization in FIG. 40 distances d.sub.1 and d.sub.2, with
corresponding RGB values RGB.sub.CAL2 and RGB.sub.CAL3, are
selected as most similar to the dressing RGB values. RGB.sub.sAMP.
Thus, it is determined that the pH value indicated by the colored
wound dressing is closer to the standardized pH values pH.sub.CAL2
and pH.sub.CAL3 associated with RGB.sub.CAL2 and RGB.sub.CAL3,
respectively, than it is to any other standardized pH values, such
as pH.sub.CAL2 associated with RGB.sub.CAL1.
[0419] In order to calculate an estimate for the dressing pH, which
falls between the selected two closest standardized pH values, the
dressing RGB values are normalized to a line segment defined by the
two selected calibration RGB values. In FIG. 40, this line segment
is shown as a line between RGB.sub.CAL2 and RGB.sub.CAL3, which
includes a point RGB.sub.NORM that is the normalized RGB value for
the wound dressing. The value RGB.sub.NORM is defined by projecting
the dressing RGB values RGB.sub.sAMP perpendicularly (or in any
other suitable way) onto the line defined by the two calibration
RGB values. The location of the RGB.sub.NORM point 140 along this
line is then used to calculate the final pH estimation for the
wound dressing. While selection of two calibration and smallest
distances is described, the illustrated process can select less or
more than two calibration values and/or smallest distances. In
addition, in certain implementations, one or more distances other
than the smallest can be utilized.
[0420] The distance between the normalized point 140 and each of
the calibration RGB points 136 (distance a.sub.1) and 138 (distance
b.sub.1) are determined and used to calculated the pH estimation.
The proportions of the line between the calibration RGB points made
up of these distances indicates where the pH.sub.SAMP value lies
between the pH.sub.CAL2 and pH.sub.CAL3 standardized values. For
example, if a.sub.1 is equal to b.sub.1, then pH.sub.SAMP is
halfway between pH.sub.CAL2 and pH.sub.CAL3. Thus, if pH.sub.CAL2
is 6.5 and pH.sub.CAL3 is 7.0, then pH.sub.SAMP is calculated as
6.75. If, on the other hand, a.sub.1 is equal to 75% of the line
between RGB.sub.CAL2 and RGB.sub.CAL3, then the pH.sub.SAMP is
closer to PH.sub.CAL3 than to pH.sub.CAL2. In that case, if
pH.sub.CAL2 is 6.5 and pH.sub.CAL3 is 7.0, then pH.sub.SAMP is
calculated as 6.875. The process returns the calculated pH.sub.SAMP
value for display to the user and storage in a patient record.
[0421] In some implementations, the analysis methods shown in FIGS.
38-40 employ a pH-sensitive wound dressing, and images captured of
that dressing, to provide the user with pH readings and wound
status feedback. A wound dressing 150 suitable for use in such
methods is shown in FIG. 41. The wound dressing 150 includes a pH
indicator 152 and a color calibration strip 154. The pH indicator
152 is the pH-sensitive component of the wound dressing 150 and
includes one or more dyes or compounds that exhibit different
colors under different pH conditions. When the wound dressing 150
is visualized, or images of the dressing are captured, the color of
the indicator 152 is used to determine a pH level for the wound to
which the dressing 150 is applied.
[0422] The color calibration strip 154 is provided on the wound
dressing 150 to facilitate interpretation of the indicator 152 to
determine pH level. The color calibration strip 154 includes five
color blocks 156a-e, each of which indicate the known color of the
dye or compound in indicator 152 at a given pH level. While only
five color blocks are shown on the dressing 150, more or fewer
color blocks could be included on the dressing. As an alternative
to providing the strip 154 directly on the dressing, the strip may
be a separate component that is placed on the dressing during image
capture. The color blocks 156a-e are selected to span the range of
expected pH values that the dressing 150 will contact, and may be
indicative of pH values spaced either at even or uneven increments
over that expected range. For example, color block 156a may
indicate the expected color of indicator 152 at a pH value of 5.0,
and each of color block 156b-e may indicate the expected color of
indicator 152 at pH values incremented by 1.0, up to a value of 9.0
for color block 156e. Other ranges and increments, varied and
constant, may be used, and more or fewer than five calibration pH
levels may be used for dressings having more or fewer color
blocks.
[0423] The dressing 150 includes orientation indicators for
automated image processing. Calibration strip location indicators
158a and 158b are provided at each end of the color calibration
strip 154. These indicators 158a and 158b can be used for image
processing to automatically detect the color blocks 156a-e. A
processing system may locate the indicators 158a and 158b in a
received image and draw a line between the two indicators. The
system may then identify each of color blocks 156a-e along the
drawn line. This approach may facilitate identification of the
color blocks in images in which the dressing 150 is not optimally
aligned, for example when the calibration color strip is not
straight relative to an alignment frame in a captured image.
[0424] The dressing 150 also includes corner indicators 160a-d for
automated image processing to identify the location of the pH
indicator 152. As with the indicators 158a and 158b, the corner
indicators 160a-d can be detected by an image processing system and
used to re-orient an image of the dressing 150 that is not
optimally aligned during image capture. In some implementations, it
may be preferable to identify a particular region of interest
within the pH indicator 152 that is used for color analysis, and
the corner indicators 160a-d may be used to identify that region.
For example, the image process system may define an X 162 extending
between the corner indicators 160a-d. The intersection of the two
lines that form the X 162 may then be processed to define center
point 164 that identifies the center of the pH indicator 152. From
this center point 164, the region of interest for analysis can be
defined.
[0425] Various implementations of devices that are usable for the
methods and wound systems described above for providing pH reading
and monitoring are envisioned, including both local user devices
and processing systems as well as remote server systems in
communication with local devices over a network. For ease of
illustration, embodiments of these devices are described below with
respect to illustrative user devices, servers, and networks. The
systems, devices, and methods disclosed herein, however, may be
adapted to other implementations and other embodiments of such
devices and networks.
[0426] As used herein, "user device" includes, without limitation,
any suitable combination of one or more devices configured with
hardware, firmware, and software to carry out one or more of the
computerized techniques described herein. A user device can be any
computing device that is capable of receiving user input, for
example receiving images, and providing responsive analysis, for
example providing calculated pH values or trends, to a user either
as a stand-alone device or in communication with an external
processing system, such as a server, over a communication network.
For example, a user device may include a mobile computing device
(e.g., a laptop computer, a tablet computer, a personal digital
assistant (PDA), a mobile telephone (such as a smartphone), or a
camera) or a stationary computing device (e.g., a personal
computer, stationary telephone, or other computing device). A user
device is preferably capable of wireless communications for
interfacing with external systems. However, devices without
wireless communication capabillties may be used without departing
from the scope of this disclosure. A user device may include one or
more cameras, including both front-facing and rear-facing cameras,
for capturing images of wound dressings. In some implementations, a
user device is a device worn by a user such as augmented reality
glasses. A user device may also include software for generating or
editing images.
[0427] As used herein, the terms "processor," "processing
circuitry," or "computing device" refers to one or more computers,
microprocessors, microcontrollers, digital signal processors,
programmable logic devices, field-programmable gate arrays (FPGAs),
application-specific integrated circuits (ASICs), etc., and may
include a multi-core processor (e.g., dual-core, quad-core,
hexa-core, or any suitable number of cores) or supercomputer. It
may also refer to other devices configured with hardware that
includes logic circuitry, firmware, and software to carry out one
or more of the computerized techniques described herein. Processors
and processing devices may also include one or more memory devices
for storing inputs, outputs, and data that is currently being
processed. An illustrative computing device, which may be used to
implement any of the processing circuitry and servers described
herein, is described in detail below with reference to FIG. 44.
[0428] As used herein, "user interface" includes, without
limitation, any suitable combination of one or more input devices
(e.g., keypads, a mouse, touch screens, trackballs, voice
recognition systems, gesture recognition systems, accelerometers,
RFID and wireless sensors, optical sensors, solid-state compasses,
gyroscopes, stylus input, joystick, etc.) and/or one or more output
devices (e.g, visual displays, speakers, tactile displays, printing
devices, etc.) For example, user interfaces can include a display
(which may be a touch-sensitive color display, optical projection
system, or other display) for graphically receiving and providing
information to the user.
[0429] FIGS. 42 and 43 depict embodiments of device, a computing
device, such as a server, and network structures that may be used
to implement the systems and methods disclosed herein. FIG. 42 is a
block diagram of a computerized system 170 for providing automated
reading and monitoring of wound pH status and trends. Generally, in
system 170, a user device 172 and server 180 are connected over a
communications network 178. The user device 172 includes processing
circuitry 174 and a user interface 176. The server 180 includes
processing circuitry 182 and memory 184.
[0430] During wound evaluation and monitoring, an image of a wound
dressing having a pH color indicator, such as the dressing 150
discussed above, is captured by the user device 172 and transmitted
to the server 180 over network 178 in transmission 186. The
processing circuitry 182 at the server 180 analyzes the received
image and provides feedback, for example a calculated pH value,
over the network 178 in transmission 188. In addition to images and
pH values, the transmission 186 and 188 may include any other
information provided by the user or sent by the server 180, for
example any additional user input or requests may be provided in
transmission 186 and any additional information such as patient pH
trends and diagnoses may be provided in transmission 188.
[0431] The network 178 couples the user device 172 and server 180
and carries transmissions, such as transmissions 186 and 188,
between the two components. Communications network 178 may be any
suitable network for exchanging information between user device 172
and server 180. For example, communications network 178 can include
the Internet, a mobile phone network, mobile voice or data network
(e.g., a 3G, 4G, or LTE network), cable network, public switched
telephone network, a satellite network, or other type of
communications network or combinations of communications networks.
The user device 172 and server 180 can communicate using one or
more communications paths, such as a satellite path, a fiber-optic
path, a cable path, a path that supports Internet communications,
free-space connections (e.g., for broadcast or other wireless
signals), or any other suitable wired or wireless communications
path or combination of such paths. The transmissions sent over the
communications may be encrypted to provide secure data
transmissions. The secure transmission is preferable for the
sensitive patient and medical information sent by the devices.
[0432] Only one server 180 and one user device 172 are shown in
FIG. 42 to avoid complicating the drawing, but the system 170 can
support multiple servers and multiple user devices. For example,
rather than being located in the single server 180, processor 182
may be located in a first server to provide image processing and
analysis, while memory 184 may be located in a second server to
provide data storage and retrieval. Multiple servers may operate
together as a cluster or as a distributed computing network.
[0433] In some implementations, the system 170 is implemented in a
cloud computing environment in which one or more of the components
are provided by different processing and storage services connected
via the Internet or other communications system. In a cloud
computing environment, various types of computing services for
content sharing, storage, or distribution are provided by a
collection of network-accessible computing and storage resources.
For example, the cloud can include a collection of server computing
devices, which may be located centrally or at distributed locations
that provide cloud-based services to various types of users and
devices connected via a network such as the Internet via
communications network 178. These cloud resources may include one
or more content sources and one or more data sources.
[0434] In addition or in the alternative, the remote computing
sites may include other user devices, such as user medical devices,
user computer devices, and wireless user communications devices.
For example, the other user devices may provide access to stored
copies of data or images. The user devices may operate in a
peer-to-peer manner without communication with the server 180. The
cloud provides access to services, such as content storage, content
sharing, or social networking services, among other examples, as
well as access to any content described below. Services can be
provided in the cloud through cloud computing service providers, or
through other providers of online services. For example, the
cloud-based services can include a content storage service, a
content sharing site, a social networking site, or other services
via which user-sourced content is distributed for viewing by others
on connected devices. These cloud-based services may allow a user
device to store content to the cloud and to receive content from
the cloud rather than storing content locally and accessing
locally-stored content. Cloud resources may be accessed by user
device 172 using, for example, a web browser, a desktop
application, a mobile application, and/or any combination of access
applications. In some implementations, a user device receives
content from multiple cloud resources simultaneously. For example,
a user device can access data and information from one cloud
resource while downloading or uploading content to or from a second
cloud resource. A user device may also download or upload content
to or from multiple cloud resources for more efficient downloading
or uploading.
[0435] While FIG. 42 depicts a network-based system for providing
wound monitoring and wound pH determinations, the functional
components of the system 170 may be implemented as one or more
components included within or local to a user device. For example,
FIG. 43 depicts a user device 190 that includes processing
circuitry 192, a user interface 194, and memory 196. The processing
circuitry 194 may be configured to perform any or all of the
functions of processing circuitry 174 and 182 of FIG. 42, the
memory 196 may be configured to store any or all of the data stored
in memory 184 of FIG. 42, and the user interface 194 may be
configured to perform any of the input and output functions
described herein for the user interface 176 of FIG. 42. In some
implementations, the user device 190 is configured to perform all
of the functions described herein for image capture, image
analysis, pH calculation, patient and pH data storage, and user
interaction described herein for wound monitoring. The data stored
in memory 196 can be encrypted and require password authorization
for access to protect sensitive patient and medical
information.
[0436] FIG. 44 shows a block diagram of an illustrative computing
device 200, which may be any of the computerized components of the
systems in FIGS. 42 and 43, for performing any of the processes
described herein. Each of the components of the systems 170 or 190
described in FIGS. 42 and 43 may be implemented on one or more
computing device 200. In certain aspects, a plurality of the
components of these systems may be included within one computing
device 200. In certain implementations, a component and a storage
device may be implemented across several computing devices 200. The
computing device 200 includes at least one communications interface
208, an input/output controller 210, system memory 201, and one or
more data storage device 211. The system memory 201 includes at
least one random access memory (RAM 202) and at least one read-only
memory (ROM 204). These elements are in communication with a
central processing unit (CPU 206) to facilitate the operation of
the computing device 200.
[0437] The computing device 200 may be configured in many different
ways. For example, the computing device 200 may be a conventional
standalone computer or alternatively, the functions of computing
device 200 may be distributed across multiple computer system and
architectures. In FIG. 44, the computing device 200 is linked, via
network or local network, to other servers or systems. The
computing device 200 may be configured in a distributed
architecture, wherein databases and processing circuitry is housed
in separate units or locations. Some units perform primary
processing functions and contain at a minimum a general controller
or a processing circuitry and a system memory. In distributed
architecture implementations, each of these units may be attached
via the communications interface 208 to a communications hub or
port (not shown) that serves as a primary communication link with
other servers, client or user computers and other related devices.
The communications hub or port may have minimal processing
capability itself, serving primarily as a communications router. A
variety of communications protocols may be part of the system,
including, but not limited to, Ethernet, SAP, SAS.TM., ATP,
BLUETOOTH.TM., GSM, DICOM and TCP/IP.
[0438] Communications interface 208 is any suitable combination of
hardware, firmware, or software for exchanging information with
external devices. Communications interface 208 may exchange
information with external systems using one or more of a cable
modem, an integrated services digital network (ISDN) modem, a
digital subscriber line (DSL) modem, a telephone modem, an Ethernet
card, or a wireless modem for communications with other devices, or
any other suitable communications interface. Such communications
may involve the Internet or any other suitable communications
networks 178 as discussed in relation to FIG. 42. In addition, the
communications interface 208 may include circuitry that enables
peer-to-peer communication, or communication between user devices
in locations remote from each other.
[0439] The CPU 206 comprises a processor, such as one or more
conventional microprocessors and one or more supplementary
co-processors such as math co-processors for offloading workload
from the CPU 206. The CPU 206 is in communication with the
communications interface 208 and the input/output controller 210,
through which the CPU 206 communicates with other devices such as
other servers, user terminals, or devices. The communications
interface 208 and the input/output controller 210 may include
multiple communication channels for simultaneous communication
with, for example, other processors, servers or client
terminals.
[0440] The CPU 206 is also in communication with the data storage
device 211 and system memory 201. The data storage device 211 and
system memory 201 may comprise an appropriate combination of
magnetic, optical or semiconductor memory, and may include, for
example, RAM 202, ROM 204, flash drive, an optical disc such as a
compact disc or a hard disk or drive. The system memory 201 may be
any suitable combination of fixed and/or removable memory, and may
include any suitable combination of volatile or non-volatile
storage. The memory 201 may be physically located inside a user
device or server or may be physically located outside of the user
device (e.g., as part of cloud-based storage) and accessed by the
user device over a communications network. The CPU 206 and the data
storage device each may be, for example, located entirely within a
single computer or other computing device; or connected to each
other by a communication medium, such as a USB port, serial port
cable, a coaxial cable, an Ethernet cable, a telephone line, a
radio frequency transceiver or other similar wireless or wired
medium or combination of the foregoing. For example, the CPU 206
may be connected to the data storage device via the communications
interface 208. The CPU 206 may be configured to perform one or more
particular processing functions.
[0441] The data storage device 211 may store, for example, (i) an
operating system 212 for the computing device 200; (ii) one or more
applications 214 (e.g., computer program code or a computer program
product) adapted to direct the CPU 206 in accordance with the
systems and methods described here, and particularly in accordance
with the processes described in detail with regard to the CPU 206;
and/or (iii) database(s) 216 adapted to store information that may
be utilized by the program.
[0442] The operating system 212 and applications 214 may be stored,
for example, in a compressed, an uncompiled and an encrypted
format, and may include computer program code. The instructions of
the program may be read into a main memory of the processing
circuitry from a computer-readable medium other than the data
storage device, such as from the ROM 204 or from the RAM 202. While
execution of sequences of instructions in the program causes the
CPU 206 to perform the process steps described herein, hard-wired
circuitry may be used in place of, or in combination with, software
instructions for implementation of the processes of systems and
methods described in this application. Thus, the systems and
methods described are not limited to any specific combination of
hardware and software.
[0443] Suitable computer program code may be provided for
performing one or more functions as described herein. The program
also may include program elements such as an operating system 212,
a database management system and "device drivers" that allow the
processing circuitry to interface with computer peripheral devices
(e.g., a video display, a keyboard, a computer mouse, etc.) via the
input/output controller 210.
[0444] The term "computer-readable medium" as used herein refers to
any non-transitory medium that provides or participates in
providing instructions to the processing circuitry of the computing
device 200 (or any other processing circuitry of a device described
herein) for execution. Such a medium may take many forms, including
but not limited to, non-volatile media and volatile media.
Non-volatile media include, for example, optical, magnetic, or
opto-magnetic disks, or integrated circuit memory, such as flash
memory. Volatile media include dynamic random access memory (DRAM),
which typically constitutes the main memory. Common forms of
computer-readable media include, for example, a floppy disk. a
flexible disk, hard disk, magnetic tape, any other magnetic medium,
a CD-ROM, DVD, any other optical medium, punch cards, paper tape,
any other physical medium with patterns of holes, a RAM, a PROM, an
EPROM or EEPROM (electronically erasable programmable read-only
memory), a FLASH-EEPROM, any other memory chip or cartridge, or any
other non-transitory medium from which a computer can read.
[0445] Various forms of computer readable media may be involved in
carrying one or more sequences of one or more instructions to the
CPU 206 (or any other processing circuitry of a device described
herein) for execution. For example, the instructions may initially
be borne on a magnetic disk of a remote computer (not shown). The
remote computer can load the instructions into its dynamic memory
and send the instructions over an Ethernet connection, cable line,
or even telephone line using a modem. A communications device local
to a computing device 200 (e.g., a server) can receive the data on
the respective communications line and place the data on a system
bus for the processor. The system bus carries the data to main
memory, from which the processing circuitry retrieves and executes
the instructions. The instructions received by main memory may
optionally be stored in memory either before or after execution by
the processor. In addition, instructions may be received via a
communication port as electrical, electromagnetic or optical
signals, which are exemplary forms of wireless communications or
data streams that carry various types of information.
[0446] The implementation of the methods and systems discussed
above provides prompt and accurate wound status and progression
feedback to a patient or physician for monitoring or adjusting
wound care. Whether the image processing, pH calculation, and data
storage is provided locally at a user's device or remotely at one
or more server or cloud components, a local device provides an
interface to the user for providing and receiving data and
information that is used in or results from such processing and
data storage. The series of screenshots discussed below and shown
in FIGS. 45-50 demonstrate data and information that may be
transmitted to or received from a user, either on a local user
device or on an accessory device in communication with a user
device. It will be understood that the screens, fields, and data
shown in the displays in FIGS. 45-50 may be modified or omitted as
desired, and the display descriptions below do not limit or exclude
the displays and data that may be relayed to a user.
[0447] FIG. 45 shows an illustrative display 302 on a user device
300 for identifying patients and receiving user selections of a
patient. Such selection may be used, for example, to identify a
particular patient being monitored for current pH value readings
from a plurality of patients who use the same device 300 or who
visit the same doctor who uses the device 300 for patient
monitoring. The display 302 facilitates identification and tracking
of the patients in such situation, when multiple records are
accessed from the same device. Depending on the system in which the
user device 300 is implemented, the list of patients may provide
access to locally-stored data and information specific to each
patient, or may provide access to data and information stored
locally. In response to user selection of a patient when data is
stored locally, the user device 300 accesses the locally stored
data to display to the user or to update a stored record with a new
pH reading. In response to user selection of a patient when data is
stored remotely, the user device 300 transmits a request to the
remote storage device to send the data for user display or
transmits a new pH reading to be added to the remotely-stored
record.
[0448] Wound monitoring systems may also provide automated patient
identification that determines the patient from the wound dressing
image. A wound dressing may include a name, number, barcode, QR
code, or other unique identifier that is related with a particular
patient. The identifier may be included on a wound dressing, such
as dressing, 150 in FIG. 41, and a box of bandages can all include
the same identifier. Alternatively, the identifier may be provided
separate from a dressing, for example, as a sticker, and the
patient or physician may transfer the identifier to a new dressing
each time the wound bandage is changed. When the bandage and
identifier are imaged for the first time, the device alerts the
user that the identifier has not been associated with a patient and
provides the display 302 for the user to select the patient. On
subsequent readings, the patient is automatically determined from
the identifier, and the display 302 is bypassed.
[0449] The screen 302 includes a list of patients each identified
by name, for example "Patient 1" for identifier 304 in the list.
From this list, a user can select one of the identifiers to access
records for the patient; begin a new wound pH reading for the
patient, view or edit identifying information for the patient, or
perform any other desired function for that particular patient. In
situations where the list of patients is quite long, a search query
box 306 may be included to facilitate patient selection without
requiring a user to scroll through the long list of patients to
find the desired identifier. The list of patient identifiers may
automatically update in real time as a user types in the query box
306 to filter the list and eliminate any patient identifiers that
do not contain the query being entered.
[0450] If a new patient is being monitored, the patient or the
patient's physician may select the new patient option 308 to add a
new record to the database of stored patient information and data.
When a user selects the new patient option 308, a prompt screen is
displayed to the user for identification information to be used for
the new patient's record. The display 310 on user device 300 shown
in FIG. 46 depicts an illustrative example of such a new patient
prompt screen. The display 310 includes fields for patient
identification and information that can be used to identify the
particular patient and associate any records kept from pH
monitoring with the particular patient to which they relate. While
the display 310 includes particular information fields, some of the
fields shown may be omitted, or additional information fields may
be included in the display 310, depending on the information
desired for patient record keeping in a particular
implementation.
[0451] The display 310 includes a first name field 312, last name
field 314, date of birth field 316, and sex field 318 for
identifying the specific patient. These standard identifying fields
can be stored in patient records for each patient in a given
system, and can be used to sort the patients or filter the patients
as desired. The first name field 312 and last name field 314 in
particular can be used to efficiently identify or find patients,
for example by searching for patients in a list of records using a
search like the search query box 306 shown in FIG. 45.
[0452] The display 310 also includes a physician name field 320 and
a patient ID field 322 that may be used to connect physicians and
patients in certain implementations. The physician name field 320
may be used, for example, in systems that store patient records for
many patients and for patients of different physicians. For
example, a cloud computing system may be maintained by a provider
of the pH monitoring application running on user device 300, or by
the provider of wound dressings used to monitor pH. The cloud
system may use the physician field 320 to group patient records by
physician and provide a given physician with access to the records
for only his or her patients. In such implementations, the patient
ID field 322 may be used to facilitate record keeping for
physicians. Each physician may assign ID numbers to each patient
for easier record keeping, and the pH monitoring readings for each
patient may be stored by ID number in addition to patient name. For
security purposes, the display 310 may also include password fields
324 for setting and confirming a password for each new patient that
is later required to access any records or take new readings for
the particular patient.
[0453] The pH readings that are stored for individual patients are
obtained from images captured by the user device 300. The device
300, preferably through an application running on the device,
provides a user with image capture cues to facilitate capturing
quality images that will result in reliable pH readings for a wound
dressing. Display 326 on user device 300 in FIG. 47 shows an
embodiment of such an image capture screen. The display 326
includes a patient identifier 328, image capture screen 330, and
tabs menu 340. The patient identifier 328 displays a selected
patient for whom a reading is being taken for implementations in
which the patient is selected before pH readings are obtained. In
implementations where images and pH readings can be obtained and
the associated patient identified after the readings, the patient
identifier 328 may be blank or may be omitted from the display
326.
[0454] The tabs menu 340 facilitates navigation between the various
screens provided on user device 300, and may be included or omitted
from any of the displays discussed herein as desired. The menu 340
includes a patients tab 342 for accessing a list of patients for
whom records are stored and accessible, a pH reading tab 344 to
access the image capture display 326 and take readings, a trend tab
346 to access a list or graph of past readings for a particular
patient, and a settings tab 348 to access general configurable
application and image capture settings.
[0455] The image capture screen 330 of display 326 helps a user
take quality images of wound dressings, for example dressing 336 in
FIG. 47, to provide reliable and repeatable pH readings. The screen
330 displays a guiding frame 332 for a user to indicate the optimal
orientation of dressing 336 for image capture. The guiding frame
332 gives the user a visual cue to align the dressing 336 before
causing the user device 300 to capture an image of the dressing 336
for pH reading. In addition to providing the guiding frame 332, the
user device 300 may monitor the orientation of the dressing 336,
for example by detecting the location of corner indicators 350 or
calibration strip indicators 352, and automatically capture an
image for processing when the dressing 336 is adequately aligned
with the guiding frame 332. Once the pH indicator 334, color
calibration strip 338, corner indicators 350, and calibration strip
indicators 352 are all positioned within the guiding frame 332, the
user is provided with visual confirmation that a suitable image of
the dressing 336 can be captured, whether done manually by pressing
a capture button or automatically by the user device 300.
[0456] An image that is captured in the image capture screen 330 is
processed, either locally at user device 300 or remotely at a
processor in communication with user device 300 over a network, to
return a calculated pH value for the wound dressing 336. Display
354 in FIG. 48 shows an illustrative screen that displays the
calculated value to a patient or physician. The display 354
includes a reading window 356 that provides the user with the
calculated pH 358 for the dressing image that was captured. The
window 356 also presents the user with an accept option 360 and a
reject option 362 that a user can use to indicate whether or not
the calculated pH 358 is reasonable or acceptable. If a user
determines that the calculated pH 358 is reasonable, he or she may
select the accept option 360, and the calculated pH 358 can be
added to the patient's record. If a user determines that the
calculated pH 358 is not reasonable, for example if it is
nonsensical or seems either inconsistent or too high or low, the
user can select the reject option 362. If the reject option 362 is
selected, the calculated pH 358 may not be stored in a patient's
record, or may be stored in the record with a special flag to
indicate the calculated pH 358 was marked as unreliable or wrong.
Optionally, the user device 300 may provide the user with a prompt
or additional option to capture another dressing image if the
reject option 362 is selected.
[0457] The user device 300 also provides a user with screens that
allow a patient or physician to review patient data either after a
reading is accepted from display 354 in FIG. 48, after a patient is
selected from display 302 in FIG. 45, after trend tab 346 is
selected from display 326, or when patient records are accessed
from any other screens. The displays of user device 300 shown in
FIGS. 49 and 50 show screens that may be implemented to provide a
patient or physician with a data record review interface.
[0458] FIG. 49 shows a display 364 on user device 300 that provides
a graphical representation of pH reading history for a particular
patient. The display 364 includes a graph 366 showing a trend 368
in calculated pH values over time for an identified patient
"Patient 1." The trend 368 plots the last seven pH values that were
obtained for the patient in the graph 366. More or fewer than seven
pH values may be displayed in the graph 366, and the size and
spacing of the graph may be scaled as appropriate for showing more
of fewer pH data points.
[0459] The display 364 also shows a last reading window 370 that
identifies the last calculated pH value 372 to the user. This
calculated pH value 372 corresponds to the last point 376 plotted
in trend 368 of graph 366. The window 370 also identifies the date
and time 374 at which the calculated pH value 372 was obtained for
the patient. At the bottom of display 364, a list option 378 is
provided. If a user selects the list option 378, the user device
364 displays a list of all of the calculated pH values plotted in
the graph 366, along with date and time information and any other
desired identification information for each point.
[0460] FIG. 50 shows a list display 380 that may be displayed in
response to a user selection of the list option 378 of display 364.
The display 380 includes a data list 382 that shows the calculated
pH value and corresponding date and time for each data point
plotted in the graph 366 of FIG. 49. While seven data points are
shown in the list 382, any number of data points can be displayed,
and the list 382 can be scaled accordingly to fit the desired
number of points. If there are too many points to fit on the
display 380, the list 382 may be scrollable to allow the user to go
backwards and forwards through the serial data points. In addition
to the list 382, the display 380 includes a view graph option 384
that allows the user to toggle the user device 300 to a graphical
display of the data in the list 382, for example by returning to
the screen 364 of FIG. 49 if the graph option 384 is selected.
EXAMPLE EMBODIMENTS
[0461] Group A
[0462] A1. A method of monitoring a wound, comprising:
[0463] capturing, with a user device, an image of a wound
dressing;
[0464] determining the color of a pH indicator on the wowld
dressing, wherein determining the color comprises extracting RGB
values from the captured image;
[0465] calculating a pH value for the wound dressing from the
dressing RGB values; and
[0466] displaying, on the user device, an indication of the
calculated pH value.
[0467] A2. The method of A1, further comprising displaying, on the
user device, a guiding frame during image capture, wherein the
guiding frame provides an indication of proper wound dressing
alignment to a user.
[0468] A3. The method of A2, further comprising detecting, with the
user device, the alignment of the wound dressing relative to the
displayed guide frame, wherein the image is automatically captured
by the user device when the wound dressing is properly aligned with
the guiding frame.
[0469] A4. The method of any of the preceding embodiments, further
comprising:
[0470] rejecting, with the user device, an image having inadequate
light or excessive shadow; and
[0471] displaying, on the user device, a request to a user to
capture a new image.
[0472] A5. The method of any of the preceding embodiments, further
comprising displaying, on the user device, an option to accept or
reject the calculated pH value when the calculated pH value is
displayed.
[0473] A6. The method of any of the preceding embodiments, further
comprising storing, in memory on the user device, the calculated pH
value in a record of pH values.
[0474] A7. The method of A6, further comprising receiving, with the
user device, user input identifying a particular patient, wherein
the stored record is associated with the particular patient.
[0475] A8. The method of A7, wherein the user input comprises a
selection of the particular patient from a list of stored
patients.
[0476] A9. The method of A7, wherein the user input comprises
identification information for a new patient.
[0477] A10. The method of any of A6-A9, further comprising
displaying, on the user device, a trend of pH values for the
particular patient.
[0478] A11. The method of A10, wherein the displayed trend
comprises at least one of a graph and a list of pH values.
[0479] A12. The method of any of the preceding embodiments, wherein
extracting dressing RGB values from the captured image comprises
determining individual pixel RGB values for each one of a plurality
of pixels in the image and averaging the individual pixel RGB
values for the plurality of pixels to determine the dressing RGB
values.
[0480] A13. The method of A12, further comprising defining a center
point of the captured image.
[0481] A14. The method of A13, further comprising defining a
dressing circle region around the center point of the captured
image, wherein the dressing circle region comprises the plurality
of pixels for which the individual pixel RGB values are
determined.
[0482] A15. The method of A14, wherein the dressing circle region
has a radius between about 5 and about 100 pixels.
[0483] A16. The method of A15, wherein the dressing circle region
has a radius between about 10 and about 50 pixels.
[0484] A17. The method of A16, wherein the dressing circle region
has a radius between about 20 and about 30 pixels.
[0485] A18. The method of any of the preceding embodiments, further
comprising capturing, with the user device, an image of a color
calibration strip.
[0486] A19. The method of A18, wherein the color calibration strip
is captured in the same image as the wound dressing.
[0487] A20. The method of A18 or A19, further comprising extracting
calibration RGB values from the image of the color calibration
strip for each of a plurality of color blocks in the color
calibration strip.
[0488] A21. The method of A20, wherein:
[0489] each color block is associated with a standardized pH value;
and
[0490] the pH value for the wound dressing is calculated using the
dressing RGB values and the calibration RGB values.
[0491] A22. The method of A20 or A21, wherein extracting
calibration RGB values for each of the plurality of color blocks
comprises determining individual pixel RGB values for each one of a
plurality of pixels in a color block and averaging the individual
pixel RGB values for the plurality of pixels in the color block to
determine the calibration RGB values for the color block.
[0492] A23. The method of A22, further comprising defining a center
point of each of the plurality of color blocks.
[0493] A24. The method of A23, wherein the center points are
defined from alignment indicators positioned on either side of the
color calibration strip.
[0494] A25. The method of A23 or A24, further comprising defining a
calibration circle region around the center point of each color
block, wherein each of the calibration circle regions comprises the
plurality of pixels for which the individual pixel RGB values are
determined in each color block.
[0495] A26. The method of A25, wherein each of the calibration
circle regions has a radius between about 3 and about 10
pixels.
[0496] A27. The method of A26, wherein each of the calibration
circle regions has a radius of about 5 pixels.
[0497] A28. The method of any of A18-A27, further comprising
calculating a distance between the dressing RGB values and each of
the calibration RGB values in a three-dimensional space.
[0498] A29. The method of A28, further comprising:
[0499] determining the two smallest calculated distances; and
[0500] calculating the pH value for the wound dressing based on the
RGB calibration values and standardized pH values associated with
the two smallest distances.
[0501] A30. The method of A29, further comprising:
[0502] normalizing the dressing RGB values to a line defined by the
two RGB calibration values associated with the two shortest
distances; and
[0503] calculating the pH value for the wound dressing from the
normalized position of the dressing RGB values on the line.
[0504] Group B
[0505] B1. A method of monitoring a wound, comprising:
[0506] receiving, at a server, an image of a wound dressing;
[0507] determining the color of a pH indicator on the wound
dressing, wherein determining the color comprises extracting
dressing RGB values from the received image;
[0508] calculating a pH value for the wound dressing from the
dressing RGB values; and
[0509] transmitting, from the server, an indication of the
calculated pH value.
[0510] B2. The method of B1, further comprising:
[0511] rejecting, at the server, an image having inadequate light
or excessive shadow; and
[0512] transmitting, from the server, a request to a user to
capture a new image.
[0513] B3. The method of B1 or B2, further comprising displaying,
on a user device in communication with the server, the calculated
pH value with an option to accept or reject the calculated pH
value.
[0514] B4. The method of any of the preceding embodiments, further
comprising storing, in memory on the server, the calculated pH
value in a record of pH values.
[0515] B5. The method of B4, further comprising receiving, at the
server, user input identifying a particular patient, wherein the
stored record is associated with the particular patient.
[0516] B6. The method of B5, wherein the user input comprises a
selection of the particular patient from a list of stored
patients.
[0517] B7. The method of B6, wherein the user input comprises
identification information for a new patient.
[0518] B8. The method of any of B4-B7, further comprising
transmitting, from the server, a trend of pH values for the
particular patient for display on a user device in communication
with the server.
[0519] B9. The method of B8, wherein the trend comprises at least
one of a graph and a list of pH values.
[0520] B10. The method of any of the preceding embodiments, wherein
extracting dressing RGB values from the received image comprises
determining individual pixel RGB values for each one of a plurality
of pixels in the image and averaging the individual pixel RGB
values for the plurality of pixels to determine the dressing RGB
values.
[0521] B11. The method of B10, further comprising defining a center
point of the received image.
[0522] B12. The method of B11, further comprising defining a
dressing circle region around the center point of the received
image, wherein the dressing circle region comprises the plurality
of pixels for which the individual pixel RGB values are
determined.
[0523] B13. The method of B12, wherein the dressing circle region
has a radius between about 5 and about 100 pixels.
[0524] B14. The method of B13, wherein the dressing circle region
has a radius between about 10 and about 50 pixels.
[0525] B15. The method of B14, wherein the dressing circle region
has a radius between about 20 and about 30 pixels.
[0526] B16. The method of any of the preceding embodiments, further
comprising receiving, at the server, an image of a color
calibration strip.
[0527] B17. The method of B17, wherein the color calibration strip
is in the same received image as the wound dressing.
[0528] B18. The method of B16 or B17, further comprising extracting
calibration RGB values from the image of the color calibration
strip for each of a plurality of color blocks in the color
calibration strip.
[0529] B19. The method of B18, wherein:
[0530] each color block is associated with a standardized pH value;
and
[0531] the pH value for the wound dressing is calculated using the
dressing RGB values and the calibration RGB values.
[0532] B20. The method of B18 or B19, wherein extracting
calibration RGB values for each of the plurality of color blocks
comprises determining individual pixel RGB values for each one of a
plurality of pixels in a color block and averaging the individual
pixel RGB values for the plurality of pixels in the color block to
determine the calibration RGB values for the color block.
[0533] B21. The method of B20, further comprising defining a center
point of each of the plurality of color blocks.
[0534] B22. The method of B21, wherein the center points are
defined from alignment indicators positioned on either side of the
color calibration strip.
[0535] B23. The method of B21 or B22, further comprising defining a
calibration circle region around the center point of each color
block, wherein each of the calibration circle regions comprises the
plurality of pixels for which the individual pixel RGB values are
determined in each color block.
[0536] B24. The method of B23, wherein each of the calibration
circle regions has a radius between about 3 and about 10
pixels.
[0537] 825. The method of B24, wherein each of the calibration
circle regions has a radius of about 5 pixels.
[0538] B26. The method of any of B16-B25, further comprising
calculating a distance between the dressing RGB values and each of
the calibration RGB values in a three-dimensional space.
[0539] B27. The method of B26, further comprising:
[0540] determining the two smallest calculated distances; and
[0541] calculating the pH value for the wound dressing based on the
RGB calibration values and standardized pH values associated with
the two smallest distances.
[0542] B28. The method of B27, further comprising:
[0543] normalizing the dressing RGB values to a line defined by the
two RGB calibration values associated with the two shortest
distances; and
[0544] calculating the pH value for the wound dressing from the
normalized position of the dressing RGB values on the line.
[0545] Group C
[0546] C1. A method of monitoring a wound, comprising:
[0547] capturing, with a user device, an image of a wound dressing
having a pH indicator;
[0548] transmitting, from the user device, the captured image;
[0549] receiving, at the user device, a pH value for the wound
dressing in the captured image; and
[0550] displaying, on the user device, an indication of the
received pH value.
[0551] C2. The method of C1, further comprising displaying, on the
user device, a guiding frame during image capture, wherein the
guiding frame provides an indication of proper wound dressing
alignment to a user.
[0552] C3. The method of C2, further comprising detecting, with the
user device, the alignment of the wound dressing relative to the
displayed guide frame, wherein the image is automatically captured
by the user device when the wound dressing is properly aligned with
the guiding frame.
[0553] C4. The method of any of the preceding embodiments, further
comprising:
[0554] rejecting, with the user device, an image having inadequate
light or excessive shadow; and
[0555] displaying, on the user device, a request to a user to
capture a new image.
[0556] C5. The method of any of the preceding embodiments, further
comprising displaying, on the user device, an option to accept or
reject the received pH value when the received pH value is
displayed.
[0557] C6. The method of any of the preceding embodiments, further
comprising storing, in memory on the user device, the received pH
value in a record of pH values.
[0558] C7. The method of C6, further comprising receiving, with the
user device, user input identifying a particular patient, wherein
the stored record is associated with the particular patient.
[0559] C8. The method of C7, wherein the user input comprises a
selection of the particular patient from a list of stored
patients.
[0560] C9. The method of C7, wherein the user input comprises
identification information for a new patient.
[0561] C10. The method of any of C6-C9, further comprising
displaying, on the user device, a trend of pH values for the
particular patient.
[0562] C11. The method of C10, wherein the displayed trend
comprises at least one of a graph and a list of pH values.
[0563] C12. The method of any of the preceding embodiments, further
comprising:
[0564] determining, at a server in communication with the user
device, individual pixel RGB values for each one of a plurality of
pixels in the captured image;
[0565] averaging, at the server, the individual pixel RGB values
for the plurality of pixels to determine dressing RGB values;
and
[0566] calculating, at the server, the pH value for the wound
dressing from the dressing RGB values.
[0567] C13. The method of C12, further comprising defining a center
point of the captured image.
[0568] C14. The method of C13, further comprising defining a
dressing circle region around the center point of the captured
image, wherein the dressing circle region comprises the plurality
of pixels for which the individual pixel RGB values are
determined.
[0569] C15. The method of C14, wherein the dressing circle region
has a radius between about S and about 100 pixels.
[0570] C16. The method of C15, wherein the dressing circle region
has a radius between about 10 and about 50 pixels.
[0571] C17. The method of C16, wherein the dressing circle region
has a radius between about 20 and about 30 pixels.
[0572] C18. The method of any of C12-C17, further comprising
capturing, with the user device, an image of a color calibration
strip.
[0573] C19. The method of C18, wherein the color calibration strip
is captured in the same image as the wound dressing.
[0574] C20. The method of C18 or C19, further comprising
extracting, at a server in communication with the user device,
calibration RGB values from the image of the color calibration
strip for each of a plurality of color blocks in the color
calibration strip.
[0575] C21. The method of C20, wherein:
[0576] each color block is associated with a standardized pH value;
and
[0577] the pH value for the wound dressing is calculated at the
server using the calibration RGB values.
[0578] C22. The method of C20 or C21, wherein extracting
calibration RGB values for each of the plurality of color blocks
comprises determining, at the server, individual pixel RGB values
for each one of a plurality of pixels in a color block and
averaging, at the server, the individual pixel RGB values for the
plurality of pixels in the color block to determine the calibration
RGB values for the color block.
[0579] C23. The method of C22, further comprising defining a center
point of each of the plurality of color blocks.
[0580] C24. The method of C23, wherein the center points are
defined from alignment indicators positioned on either side of the
color calibration strip.
[0581] C25. The method of C23 or C24, further comprising defining a
calibration circle region around the center point of each color
block, wherein each of the calibration circle regions comprises the
plurality of pixels for which the individual pixel RGB values are
determined in each color block.
[0582] C26. The method of C25, wherein each of the calibration
circle regions has a radius between about 3 and about 10
pixels.
[0583] C27. The method of C26, wherein each of the calibration
circle regions has a radius of about 5 pixels.
[0584] C28. The method of any of C18-C27, further comprising
calculating, at the server, a distance between the dressing RGB
values and each of the calibration RGB values in a three
dimensional space.
[0585] C29. The method of C28, further comprising:
[0586] determining the two smallest calculated distances; and
[0587] calculating the pH value for the wound dressing based on the
RGB calibration values and standardized pH values associated with
the two smallest distances.
[0588] C30. The method of C29, further comprising:
[0589] normalizing the dressing RGB values to a line defined by the
two RGB calibration values associated with the two shortest
distances; and
[0590] calculating the pH value for the wound dressing from the
normalized position of the dressing RGB values on the line.
[0591] Group D
[0592] D1. A non-transitory computer-readable medium for monitoring
a wound, wherein the computer-readable medium is encoded with
machine-readable instructions for performing the method according
to any of A1-A30, B1-B28, or C1-C30.
[0593] Group E
[0594] E1. A device for monitoring a wound, comprising:
[0595] memory;
[0596] a display; and
[0597] processing circuitry in communication with the memory and
the display, the processing circuitry being configured to perform
any of the methods of A1-A30.
[0598] Group F
[0599] F1. A server for monitoring a wound, comprising:
[0600] memory;
[0601] communications circuitry coupled to a network for
transmitting and receiving communications over the network; and
[0602] processing circuitry associated with the communications
circuitry and the memory, the processing circuitry being configured
to perform any of the methods of B1-B28.
[0603] Group G
[0604] G1. A device for monitoring a wound, comprising:
[0605] memory;
[0606] communications circuitry coupled to a network for
transmitting and receiving communications over the network; and
[0607] processing circuitry associated with the communications
circuitry and the memory, the processing circuitry being configured
to perform any of the methods of C1-C30.
[0608] Group H
[0609] H1. A system for monitoring a wound, comprising:
[0610] the server of F1; and
[0611] the device of G1.
[0612] Group I
[0613] I1. A system for monitoring a wound, comprising:
[0614] means for capturing an image of a wound dressing;
[0615] means for determining the color of a pH indicator on the
wound dressing, wherein the means for determining the color
comprises means for extracting RGD values from the captured
image;
[0616] means for calculating a pH value for the wound dressing from
the dressing RGB values; and
[0617] means for displaying an indication of the calculated pH
value.
[0618] I2. The system of I1, further comprising means for
displaying a guiding frame during image capture, wherein the
guiding frame provides an indication of proper wound dressing
alignment to a user.
[0619] I3. The system of I2, further comprising means for detecting
the alignment of the wound dressing relative to the displayed guide
frame, wherein the image is automatically captured by the means for
capturing when the wound dressing is properly aligned with the
guiding frame.
[0620] I4. The system of any of the preceding embodiments, further
comprising:
[0621] means for rejecting an image having inadequate light or
excessive shadow; and
[0622] means for displaying a request to a user to capture a new
image.
[0623] I5. The system of any of the preceding embodiments, further
comprising means for displaying an option to accept or reject the
calculated pH value when the calculated pH value is displayed.
[0624] I6. The system of any of the preceding embodiments, further
comprising means for storing the calculated pH value in a record of
pH values.
[0625] I7. The system of I6, further comprising means for receiving
user input identifying a particular patient, wherein the stored
record is associated with the particular patient.
[0626] I8. The system of I7, wherein the user input comprises a
selection of the particular patient from a list of stored
patients.
[0627] I9. The system of I7, wherein the user input comprises
identification information for a new patient.
[0628] I10. The system of any of I6-I9, further comprising means
for displaying a trend of pH values for the particular patient.
[0629] I11. The system of A10, wherein the displayed trend
comprises at least one of a graph and a list of pH values.
[0630] I12. The system of any of the preceding embodiments, wherein
means for extracting dressing RGB values from the captured image
comprises means for determining individual pixel RGB values for
each one of a plurality of pixels in the image and means for
averaging the individual pixel RGB values for the plurality of
pixels to determine the dressing RGB values.
[0631] I13. The system of I12, further comprising means for
defining a center point of the captured image.
[0632] I14. The system of I13, further comprising means for
defining a dressing circle region around the center point of the
captured image, wherein the dressing circle region comprises the
plurality of pixels for which the individual pixel RGB values are
determined.
[0633] I15. The system of I14, wherein the dressing circle region
has a radius between about 5 and about 100 pixels.
[0634] I16. The system of I15, wherein the dressing circle region
has a radius between about 10 and about 50 pixels.
[0635] I17. The system of I16, wherein the dressing circle region
has a radius between about 20 and about 30 pixels.
[0636] I18. The system of any of the preceding embodiments, further
comprising means for capturing an image of a color calibration
strip.
[0637] I19. The system of A18, wherein the color calibration strip
is captured in the same image as the wound dressing.
[0638] I20. The system of I18 or I19, further comprising means for
extracting calibration RGB values from the image of the color
calibration strip for each of a plurality of color blocks in the
color calibration strip.
[0639] I21. The system of I20, wherein:
[0640] each color block is associated with a standardized pH value;
and
[0641] the pH value for the wound dressing is calculated using the
dressing RGB values and the calibration RGB values.
[0642] I22. The system of I20 or I21, wherein the means for
extracting calibration RGB values for each of the plurality of
color blocks comprises means for determining individual pixel RGB
values for each one of a plurality of pixels in a color block and
means for averaging the individual pixel RGB values for the
plurality of pixels in the color block to determine the calibration
RGB values for the color block.
[0643] I23. The system of I22, further comprising means for
defining a center point of each of the plurality of color
blocks.
[0644] I24. The system of I23, wherein the center points are
defined from alignment indicators positioned on either side of the
color calibration strip.
[0645] I25. The system of I23 or I24, further comprising means for
defining a calibration circle region around the center point of
each color block, wherein each of the calibration circle regions
comprises the plurality of pixels for which the individual pixel
RGB values are determined in each color block.
[0646] I26. The system of I25, wherein each of the calibration
circle regions has a radius between about 3 and about 10
pixels.
[0647] I27. The system of I26, wherein each of the calibration
circle regions has a radius of about 5 pixels.
[0648] I28. The system of any of I18-I27, further comprising means
for calculating a distance between the dressing RGB values and each
of the calibration RGB values in a three-dimensional space.
[0649] I29. The system of I28, further comprising:
[0650] means for determining the two smallest calculated distances;
and
[0651] means for calculating the pH value for the wound dressing
based on the RGB calibration values and standardized pH values
associated with the two smallest distances.
[0652] I30. The system of I29, further comprising:
[0653] means for normalizing the dressing RGB values to a line
defined by the two RGB calibration values associated with the two
shortest distances; and
[0654] means for calculating the pH value for the wound dressing
from the normalized position of the dressing RGB values on the
line.
[0655] Group J
[0656] J1. A system for monitoring a wound, comprising:
[0657] means for receiving an image of a wound dressing;
[0658] means for determining the color of a pH indicator on the
wound dressing, wherein the means for determining the color
comprises means for extracting dressing RGB values from the
received image;
[0659] means for calculating a pH value for the wound dressing from
the dressing RGB values; and
[0660] means for transmitting an indication of the calculated pH
value.
[0661] J2. The system of J1, further comprising:
[0662] means for rejecting an image having inadequate light or
excessive shadow; and
[0663] means for transmitting a request to a user to capture a new
image.
[0664] J3. The system of J1 or J2, further comprising means for
displaying the calculated pH value with an option to accept or
reject the calculated pH value.
[0665] J4. The system of any of the preceding embodiments, further
comprising means for storing the calculated pH value in a record of
pH values.
[0666] J5. The system of J4, further comprising means for receiving
user input identifying a particular patient, wherein the stored
record is associated with the particular patient.
[0667] J6. The system of J5, wherein the user input comprises a
selection of the particular patient from a list of stored
patients.
[0668] J7. The system of J6, wherein the user input comprises
identification information for a new patient.
[0669] J8. The system of any of J4-J7, further comprising means for
transmitting a trend of pH values for the particular patient for
display on a user device in communication with the means for
transmitting.
[0670] J9. The system of J8, wherein the trend comprises at least
one of a graph and a list of pH values.
[0671] J10. The system of any of the preceding embodiments, wherein
the means for extracting dressing RGB values from the received
image comprises means for determining individual pixel RGD values
for each one of a plurality of pixels in the image and means for
averaging the individual pixel RGB values for the plurality of
pixels to determine the dressing RGB values.
[0672] J11. The system of J10, further comprising means for
defining a center point of the received image.
[0673] J12. The system of J11, further comprising means for
defining a dressing circle region around the center point of the
received image, wherein the dressing circle region comprises the
plurality of pixels for which the individual pixel RGB values are
determined.
[0674] J13. The system of J12, wherein the dressing circle region
has a radius between about 5 and about 100 pixels.
[0675] J14. The system of J13, wherein the dressing circle region
has a radius between about 10 and about 50 pixels.
[0676] J15. The system of J14, wherein the dressing circle region
has a radius between about 20 and about 30 pixels.
[0677] J16. The system of any of the preceding embodiments, further
comprising means for receiving an image of a color calibration
strip.
[0678] J17. The system of J17, wherein the color calibration strip
is in the same received image as the wound dressing.
[0679] J18. The system of J16 or J17, further comprising means for
extracting calibration RGB values from the image of the color
calibration strip for each of a plurality of color blocks in the
color calibration strip.
[0680] J19. The system of J18, wherein:
[0681] each color block is associated with a standardized pH value;
and
[0682] the pH value for the wound dressing is calculated using the
dressing RGB values and the calibration RGB values.
[0683] J20. The system of J18 or J19, wherein the means for
extracting calibration RGB values for each of the plurality of
color blocks comprises means for determining individual pixel RGB
values for each one of a plurality of pixels in a color block and
means for averaging the individual pixel RGB values for the
plurality of pixels in the color block to determine the calibration
RGB values for the color block.
[0684] J21. The system of J20, further comprising means for
defining a center point of each of the plurality of color
blocks.
[0685] J22. The system of J21, wherein the center points are
defined from alignment indicators positioned on either side of the
color calibration strip.
[0686] J23. The system of J21 or J22, further comprising means for
defining a calibration circle region around the center point of
each color block, wherein each of the calibration circle regions
comprises the plurality of pixels for which the individual pixel
RGB values are determined in each color block.
[0687] J24. The system of J23, wherein each of the calibration
circle regions has a radius between about 3 and about 10
pixels.
[0688] J25. The system of J24, wherein each of the calibration
circle regions has a radius of about 5 pixels.
[0689] J26. The system of any of J16-J25, further comprising means
for calculating a distance between the dressing RGB values and each
of the calibration RGB values in a three-dimensional space.
[0690] J27. The system of J26, further comprising:
[0691] means for determining the two smallest calculated distances;
and
[0692] means for calculating the pH value for the wound dressing
based on the RGB calibration values and standardized pH values
associated with the two smallest distances.
[0693] J28. The system of J27, further comprising: [0694] means for
normalizing the dressing RGB values to a line defined by the two
RGB calibration values associated with the two shortest distances;
and
[0695] means for calculating the pH value for the wound dressing
from the normalized position of the dressing RGB values on the
line.
[0696] Group K
[0697] K1. A system for monitoring a wound, comprising:
[0698] means for capturing an image of a wound dressing having a pH
indicator;
[0699] means for transmitting the captured image;
[0700] means for receiving a pH value for the wound dressing in the
captured image; and
[0701] means for displaying an indication of the received pH
value.
[0702] K2. The system of K1, further comprising means for
displaying a guiding frame during image capture, wherein the
guiding frame provides an indication of proper wound dressing
alignment to a user.
[0703] K3. The system of K2, further comprising means for detecting
the alignment of the wound dressing relative to the displayed guide
frame, wherein the image is automatically captured by the means for
capturing when the wound dressing is properly aligned with the
guiding frame.
[0704] K4. The system of any of the preceding embodiments, further
comprising:
[0705] means for rejecting an image having inadequate light or
excessive shadow; and
[0706] means for displaying a request to a user to capture a new
image.
[0707] K5. The system of any of the preceding embodiments, further
comprising means for displaying an option to accept or reject the
received pH value when the received pH value is displayed.
[0708] K6. The system of any of the preceding embodiments, further
comprising means for storing the received pH value in a record of
pH values.
[0709] K7. The system of K6, further comprising means for receiving
user input identifying a particular patient, wherein the stored
record is associated with the particular patient.
[0710] K8. The system of K7, wherein the user input comprises a
selection of the particular patient from a list of stored
patients.
[0711] K9. The system of K7, wherein the user input comprises
identification information for a new patient.
[0712] K10. The system of any of K6-K9, further comprising means
for displaying a trend of pH values for the particular patient.
[0713] K11. The system of K10, wherein the displayed trend
comprises at least one of a graph and a list of pH values.
[0714] K12. The system of any of the preceding embodiments, further
comprising:
[0715] means for determining individual pixel RGB values for each
one of a plurality of pixels in the captured image;
[0716] means for averaging the individual pixel RGB values for the
plurality of pixels to determine dressing RGB values; and
[0717] means for calculating the pH value for the wound dressing
from the dressing RGB values.
[0718] K13. The system of K12, further comprising means for
defining a center point of the captured image.
[0719] K14. The system of K13, further comprising means for
defining a dressing circle region around the center point of the
captured image, wherein the dressing circle region comprises the
plurality of pixels for which the individual pixel RGB values are
determined.
[0720] K15. The system of K14, wherein the dressing circle region
has a radius between about 5 and about 100 pixels.
[0721] K16. The system of K15, wherein the dressing circle region
has a radius between about 10 and about 50 pixels.
[0722] K17. The system of K16, wherein the dressing circle region
has a radius between about 20 and about 30 pixels.
[0723] K18. The system of any of K12-K17, further comprising means
for capturing an image of a color calibration strip.
[0724] K19. The system of K18, wherein the color calibration strip
is captured in the same image as the wound dressing.
[0725] K20. The system of K18 or K19, further comprising means for
extracting calibration RGB values from the image of the color
calibration strip for each of a plurality of color blocks in the
color calibration strip.
[0726] K21. The system of K20, wherein:
[0727] each color block is associated with a standardized pH value;
and
[0728] the pH value for the wound dressing is calculated using the
calibration RGB values.
[0729] K22. The system of K20 or K21, wherein the means for
extracting calibration RGB values for each of the plurality of
color blocks comprises means for determining individual pixel RGB
values for each one of a plurality of pixels in a color block and
means for averaging the individual pixel RGB values for the
plurality of pixels in the color block to determine the calibration
RGB values for the color block.
[0730] K23. The system of K22, further comprising means for
defining a center point of each of the plurality of color
blocks.
[0731] K24. The system of K23, wherein the center points are
defined from alignment indicators positioned on either side of the
color calibration strip.
[0732] K25. The system of K23 or K24, further comprising means for
defining a calibration circle region around the center point of
each color block, wherein each of the calibration circle regions
comprises the plurality of pixels for which the individual pixel
RGB values are determined in each color block.
[0733] K26. The system of K25, wherein each of the calibration
circle regions has a radius between about 3 and about 10
pixels.
[0734] K27. The system of K26, wherein each of the calibration
circle regions has a radius of about 5 pixels.
[0735] K28. The system of any of K18-K27, further comprising means
for calculating a distance between the dressing RGB values and each
of the calibration RGB values in a three dimensional space.
[0736] K29. The system of K28, further comprising:
[0737] means for determining the two smallest calculated distances;
and
[0738] means for calculating the pH value for the wound dressing
based on the RGB calibration values and standardized pH values
associated with the two smallest distances.
[0739] K30. The system of K29, further comprising:
[0740] means for normalizing the dressing RGB values to a line
defined by the two RGB calibration values associated with the two
shortest distances; and
[0741] means for calculating the pH value for the wound dressing
from the normalized position of the dressing RGB values on the
line.
[0742] Group L
[0743] L1. A system for monitoring a wound, comprising:
[0744] the system of any of J1-J28; and
[0745] the system of any of K1-K30.
[0746] With respect to all of Sections 1, 2, 3, 4 and 5 of the
application, the foregoing is merely illustrative of the principles
of the disclosure, and the systems, devices, and methods can be
practiced by other than the described embodiments, which are
presented for purposes of illustration and not of limitation. It is
to be understood that the systems, devices, and methods disclosed
herein, while shown for use in wound monitoring approaches using
wound dressing having color pH indicators, user devices, and
servers, may be applied to systems, devices, and methods to be used
in other approaches for wound monitoring using pH tracking or
tracking of other wound indicators using color bandages.
[0747] Variations and modifications will occur to those of skill in
the art after reviewing this disclosure. The disclosed features may
be implemented, in any combination and subcombination (including
multiple dependent combinations and subcombinations), with one or
more other features described herein. The various features
described or illustrated above, including any components thereof,
may be combined or integrated in other systems. Moreover, certain
features may be omitted or not implemented.
[0748] Examples of changes, substitutions, and alterations are
ascertainable by one skilled in the art and could be made without
departing from the scope of the information disclosed herein. All
references cited herein are incorporated by reference in their
entirety and made pact of this application.
* * * * *