U.S. patent application number 16/132115 was filed with the patent office on 2019-01-10 for wound dressing and method of treatment.
The applicant listed for this patent is Smith & Nephew PLC. Invention is credited to Julie Allen, Ben Alan Askem, Sarah Jenny Collinson, Philip Gowans, Steven Carl Mehta, Derek Nicolini, Carol Zagrabski.
Application Number | 20190008696 16/132115 |
Document ID | / |
Family ID | 49274836 |
Filed Date | 2019-01-10 |
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United States Patent
Application |
20190008696 |
Kind Code |
A1 |
Allen; Julie ; et
al. |
January 10, 2019 |
WOUND DRESSING AND METHOD OF TREATMENT
Abstract
Embodiments disclosed herein are directed to negative pressure
treatment systems and wound dressing systems, apparatuses, and
methods that may be used for the treatment of wounds. In
particular, some embodiments are directed to improved wound
dressings comprising an obscuring layer that may hide fluid
contained therein. Some embodiments may further comprise one or
more viewing windows disposed therethrough so as to enable
monitoring or examination of fluids contained therein.
Inventors: |
Allen; Julie; (Hull, GB)
; Askem; Ben Alan; (Brough, GB) ; Collinson; Sarah
Jenny; (Hull, GB) ; Mehta; Steven Carl;
(Lincoln, GB) ; Gowans; Philip; (York, GB)
; Nicolini; Derek; (Hull, GB) ; Zagrabski;
Carol; (Cheektowaga, NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Smith & Nephew PLC |
London |
|
GB |
|
|
Family ID: |
49274836 |
Appl. No.: |
16/132115 |
Filed: |
September 14, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14418874 |
Jan 30, 2015 |
10076449 |
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PCT/IB2013/002102 |
Jul 31, 2013 |
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16132115 |
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61785054 |
Mar 14, 2013 |
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61753878 |
Jan 17, 2013 |
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61753374 |
Jan 16, 2013 |
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61678569 |
Aug 1, 2012 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 13/0216 20130101;
A61F 2013/00846 20130101; A61F 2013/15243 20130101; A61F 13/00068
20130101; A61F 13/5376 20130101; A61F 13/15203 20130101; A61F
2013/00153 20130101; A61F 2013/00497 20130101; A61M 1/0088
20130101; A61F 13/0206 20130101; A61F 2013/530875 20130101; A61F
13/022 20130101; A61F 2013/00519 20130101; A61F 13/00059 20130101;
A61F 2013/00182 20130101 |
International
Class: |
A61F 13/15 20060101
A61F013/15; A61F 13/00 20060101 A61F013/00; A61F 13/02 20060101
A61F013/02; A61F 13/537 20060101 A61F013/537; A61M 1/00 20060101
A61M001/00 |
Claims
1.-95. (canceled)
96. An apparatus for dressing a wound for the application of
topical negative pressure at a wound site, comprising: an absorbent
layer having one or more slits configured to enhance conformability
when the apparatus is applied to a non-planar or contoured wound
area, the one or more slits extending at least partially across the
width of the absorbent layer; a backing layer above the absorbent
layer, the backing layer having an orifice for communicating
negative pressure to the wound site, wherein the orifice is
positioned over a portion of the absorbent layer having no slits;
and a transmission layer configured to allow for the passage of
fluid therethrough.
97.-113. (canceled)
114. The apparatus of claim 96, wherein each of the slits do not
extend entirely across the width of the dressing.
115. The apparatus of claim 96, wherein the slits are distributed
concentrically.
116. The apparatus of claim 96, wherein the one or more slits are
arc-shaped.
117. The apparatus of claim 96, wherein one of the at least one or
more slits has a different size with another of said at least one
or more slits.
118. The apparatus of claim 96, wherein the one or more slits have
an alternating pattern.
119. The apparatus of claim 96, wherein the one or more slits
comprise a cut centered adjacent an edge of the absorbent
layer.
120. An apparatus for dressing a wound comprising: an absorbent
layer having one or more slits configured to enhance conformability
when the apparatus is applied to a non-planar or contoured wound
area, the one or more slits extending at least partially across the
width of the absorbent layer; a backing layer above the absorbent
layer; and a transmission layer configured to allow for the passage
of fluid therethrough.
121. The apparatus of claim 120, wherein each of the slits do not
extend entirely across the width of the dressing.
122. The apparatus of claim 120, wherein the slits are distributed
concentrically.
123. The apparatus of claim 120, wherein the one or more slits are
arc-shaped.
124. The apparatus of claim 120, wherein one of the at least one or
more slits has a different size with another of said at least one
or more slits.
125. The apparatus of claim 120, wherein at least one slit has a
different size with another slit.
126. The apparatus of claim 120, wherein the one or more slits have
an alternating pattern.
127. The apparatus of claim 120, wherein the one or more slits
comprise a cut centered adjacent an edge of the absorbent
layer.
128. The apparatus of claim 120, wherein the backing layer is
moisture vapor permeable.
129. The apparatus of claim 120, wherein the absorbent layer
comprises a super absorbent material.
130. The apparatus of claim 120, further comprising a wound contact
layer below the transmission layer, wherein the wound contact layer
is adhered to the backing layer, and wherein the backing layer and
the wound contact layer have the same size and shape.
131. The apparatus of claim 120, wherein the transmission layer
comprises a porous material or a non-woven fabric material.
132. The apparatus of claim 120, wherein the transmission layer is
below the absorbent layer.
133. The apparatus of claim 120, further comprising an acquisition
distribution layer below the absorbent layer, wherein the
acquisition distribution layer is configured to allow distribution
of fluid.
134. The apparatus of claim 120, wherein the absorbent layer is in
contact with the backing layer.
135. An apparatus for dressing a wound comprising: an absorbent
layer having one or more slits configured to enhance conformability
when the apparatus is applied to a non-planar or contoured wound
area, the one or more slits extending at least partially across the
width of the absorbent layer; a backing layer above the absorbent
layer; and a wicking layer below the absorbent layer, the wicking
layer configured to horizontally wick fluid as it is absorbed
upward through to the absorbent layer.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application Ser. No. 61/678,569, filed Aug. 1, 2012, titled "WOUND
DRESSING AND METHOD OF TREATMENT," U.S. Provisional Application
Ser. No. 61/753,374, filed Jan. 16, 2013, titled "WOUND DRESSING
AND METHOD OF TREATMENT," U.S. Provisional Application Ser. No.
61/753,878, filed Jan. 17, 2013, titled "WOUND DRESSING AND METHOD
OF TREATMENT," and U.S. Provisional Application Ser. No.
61/785,054, filed Mar. 14, 2013, titled "WOUND DRESSING AND METHOD
OF TREATMENT," the entireties of each of which are hereby
incorporated by reference.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] Embodiments described herein relate to apparatuses, systems,
and methods the treatment of wounds, for example using dressings in
combination with negative pressure wound therapy.
Description of the Related Art
[0003] Prior art dressings for use in negative pressure have been
difficult to apply, particularly around curved or non-flat body
surfaces. Further, when used, wound exudate may soak into the
dressing, which some patients may find aesthetically unpleasing and
difficult to address in social situations.
SUMMARY OF THE INVENTION
[0004] Accordingly, certain embodiments disclosed herein relate to
improved wound dressing that exhibit enhanced conformability and
aesthetic presentation. Also disclosed are improved methods of use
and systems for use of the same, preferably in conjunction with
negative pressure wound therapy.
[0005] In one embodiment, a wound treatment apparatus for treatment
of a wound site comprises: [0006] a wound dressing comprising:
[0007] an absorbent layer configured to retain fluid, [0008] a
backing layer above the absorbent layer, and [0009] an obscuring
layer configured to at least partly visually obscure fluid within
the absorbent layer; and [0010] a fluidic connector configured to
transmit negative pressure from a negative pressure source to the
wound dressing for the application of topical negative pressure at
the wound site.
[0011] In some embodiments, the obscuring layer is above or below
the backing layer. The obscuring layer may configured to at least
partially visually obscure fluid contained within the absorbent
layer. The obscuring layer may comprise at least one viewing window
configured to allow a visual determination of the saturation level
of the absorbent layer. The at least one viewing window may
comprise at least one aperture made through the obscuring layer.
The at least one viewing window may comprise at least one uncolored
region of the obscuring layer. The viewing window may comprise an
array of dots. The array of dots may be distributed in a straight
line of dots, the straight line of dots being positioned on a
center line along a length of the absorbent layer. The straight
line of dots may comprise an array of three dots. The straight line
of dots may comprise an array of five dots. The straight line of
dots may comprise an array of eight dots. The array of dots may be
distributed in two straight lines of dots, the two straight lines
of dots positioned to be an equal distance from a center line along
a length of the absorbent layer, the two straight lines of dots
having an equal number of dots. The two straight lines of dots may
comprise an array of three dots. The two straight lines of dots may
comprise an array of five dots. The array of dots may be
distributed regularly over the obscuring layer to enable assessment
of wound exudate spread. The viewing window may be selected from
the group consisting of a graphical element or a typographical
element. The obscuring layer may comprise an auxiliary compound,
wherein the auxiliary compound may comprise activated charcoal
configured to absorb odors and configured to color or tint the
obscuring layer. The fluidic connector may comprise an obscuring
element configured to substantially visually obscure wound
exudate.
[0012] Some embodiments may further comprise an acquisition
distribution layer between the wound contact layer and the
absorbent material. The absorbent layer may comprise cellulose
fibers and between 40% and 80% (or between about 40% and about 80%)
superabsorbent particles. The obscuring layer, in a dry state, may
be configured to yield a CIE y value of 0.4 or less and a CIE x
value of 0.5 or less on a CIE x, y chromaticity diagram. The
obscuring layer, in a dry state, may have a color of Bg, gB, B, pB,
bP, P, rP, pPk, RP, O, rO, or yO on a CIE x, y chromaticity
diagram.
[0013] In some embodiments, the wound dressing further comprises an
orifice in the backing layer, the orifice configured to communicate
negative pressure to the wound site. The obscuring layer may
comprise at least one orifice viewing window configured to be
positioned adjacent to the orifice in the backing layer, the
orifice viewing window configured to allow a visual determination
of the saturation level of the absorbent layer adjacent to the
orifice. The orifice viewing window may be cross-shaped. The wound
dressing may comprise a first length corresponding to a first edge
of a wound dressing and a first width corresponding to a second
edge of the wound dressing, a first x axis runs along the first
width and a first y axis runs along the first length, wherein the
first x axis and the first y axis are in a perpendicular alignment.
The viewing window may comprise a first arm and a second arm, the
first arm of the viewing window define a second length and the
second arm defines a second width, a second x axis runs along the
second width and a second y axis runs along the second length,
wherein the second x axis and the second y axis are in a
perpendicular alignment. The second x axis and second y axis of the
viewing window is offset from the first x axis and the first y axis
of the absorbent layer. The second x axis and second y axis of the
viewing window may be aligned with the first x axis and the first y
axis of the absorbent layer. The cross-shaped viewing window may
comprise flared ends. The fluidic connector may be configured to
transmit air. The fluidic connector may comprise a filter, the
filter configured to block fluid transport past itself. The fluidic
connector may comprise a secondary air leak channel, the secondary
air leak channel configured to allow a flow of ambient air to the
wound site. The secondary air leak channel may comprise a filter.
The fluidic connector may comprise a soft fluidic connector. The
soft fluidic connector may comprise a three dimensional fabric. In
some embodiments, the three dimensional fabric is configured to
transmit therapeutic levels of negative pressure while an external
pressure up to 2 kg/cm.sup.2 is applied thereto. The soft fluidic
connector may be configured to be connected to a tube in fluid
communication with the vacuum source. The soft fluidic connector
may be configured to be connected directly to the vacuum source.
The soft fluidic connector may comprise an enlarged distal end, the
enlarged distal end configured to be connected to the wound
dressing. The apparatus may further comprise a tube connected to
the fluidic connector. The apparatus may further comprise a pump in
fluid communication with the fluidic connector. In some
embodiments, the absorbent layer comprises two or more lobes.
[0014] In another embodiment, a wound treatment apparatus for
treatment of a wound site comprises: [0015] a wound dressing
configured to be positioned over a wound site, the wound dressing
comprising: [0016] a backing layer having an upper surface and a
lower surface and defining a perimeter configured to be positioned
over skin surrounding the wound site, the backing layer including
an opening; [0017] a wound contact layer adhered to the lower
surface of the backing layer, the wound contact layer comprising an
adhesive on a lower surface thereof; [0018] an absorbent material
positioned between the backing layer and the wound contact layer,
wherein the absorbent material comprises a vertical hole positioned
below the opening in the backing layer; [0019] an obscuring layer
positioned at least partially over the absorbent material, wherein
the obscuring layer comprises a vertical hole positioned between
the opening in the backing layer and the vertical hole in the
absorbent material; [0020] one or more viewing windows extending
through the obscuring layer configured to allow visualization of
wound exudate in the absorbent material; and [0021] a port
positioned over the opening in the backing layer configured to
transmit negative pressure through the port for the application of
topical negative pressure at the wound site.
[0022] In some embodiments, the backing layer is transparent or
translucent. The backing layer may define a perimeter with a
rectangular or a square shape. The wound contact layer may be
adhered to the lower surface of the backing layer along the
perimeter of the backing layer. The hole in the obscuring layer may
have a different diameter than the hole in the absorbent material
or the opening in the backing layer. The one or more viewing
windows may be arranged in a repeating pattern across the obscuring
layer. The one or more viewing windows may have a circular
shape.
[0023] Some embodiments may further comprise an acquisition
distribution layer between the wound contact layer and the
absorbent material. The absorbent layer may comprise cellulose
fibers and between 40% and 80% (or between about 40% and about 80%)
superabsorbent particles. The obscuring layer, in a dry state, may
be configured to yield a color of Bg, gB, B, pB, bP, P, rP, pPk,
RP, O, rO, or yO on the CIE x, y chromaticity diagram.
[0024] Some embodiments further comprise a transmission layer
between the absorbent material and the wound contact layer. In some
embodiments, the apparatus further comprises a hydrophobic filter
positioned in or below the port. The absorbent material may have a
longitudinal length and a transverse width, wherein the length is
greater than the width, and wherein the width of the absorbent
material narrows in a central portion along the longitudinal length
of the absorbent material. The obscuring layer may have
substantially the same perimeter shape as the absorbent material.
The apparatus may further comprise a pump
[0025] In another embodiment, a wound treatment apparatus for
treatment of a wound site comprises: [0026] a wound dressing
configured to be conformable to a nonplanar wound comprising:
[0027] an absorbent layer comprising a contoured shape, the
contoured shape comprising a substantially rectangular body with a
waisted portion, and [0028] a backing layer above the absorbent
layer; and [0029] a fluidic connector configured to transmit
negative pressure from a negative pressure source to the wound
dressing for the application of topical negative pressure at a
wound site.
[0030] Some embodiments may further comprise a wound contact layer.
The backing layer may be rectangular. In some embodiments, the
negative pressure source is a pump.
[0031] In some embodiments, the wound dressing has a longer axis
and a shorter axis, and wherein the waisted portion configured to
be on the longer axis. The apparatus may further comprise an
obscuring layer configured to at least partly visually obscure
fluid within the absorbent layer. The obscuring layer may comprise
at least one viewing window configured to allow a visual
determination of the saturation level of the absorbent layer. The
viewing window may comprise an array of dots. The fluidic connector
may be located along a side or corner of the rectangular body.
[0032] Some embodiments may further comprise an acquisition
distribution layer between the wound contact layer and the
absorbent material. The absorbent layer may comprise cellulose
fibers and 40%-80% (or about 40% to about 80%) superabsorbent
particles. The obscuring layer, in a dry state, may be configured
to yield a color of Bg, gB, B, pB, bP, P, rP, pPk, RP, O, rO, or yO
on the CIE x, y chromaticity diagram.
[0033] In yet another embodiment, an apparatus for dressing a wound
for the application of topical negative pressure at a wound site,
comprises: [0034] an absorbent layer having one or more slits
extending at least partially across the width of the absorbent
layer; and [0035] a backing layer above the absorbent layer, the
backing layer having an orifice for communicating negative pressure
to the wound site, wherein the orifice is positioned over a portion
of the absorbent layer having no slits.
[0036] In some embodiments, the one or more slits comprise one or
more concentric arcs.
[0037] In another embodiment, a wound treatment apparatus
comprises: [0038] a wound dressing configured to be conformable to
a nonplanar wound comprising: [0039] an absorbent layer above the
contact layer, the absorbent layer comprising a contoured shape,
the contoured shape comprising two or more lobes, and [0040] a
backing layer above the absorbent layer.
[0041] In some embodiments, the wound treatment apparatus comprises
a pump. The wound dressing may comprise a fluidic connector
configured to transmit negative pressure from a pump to the wound
dressing for the application of topical negative pressure at a
wound site. The wound dressing may also comprise a wound-facing
contact layer. The contoured shape may comprise three lobes. The
contoured shape may comprise four lobes. The two or more lobes may
comprise rounded projections. The apparatus may comprise two or
more lobes flared lobes. The contoured shape may be oval-shaped.
The contoured shape may comprise six lobes. The apparatus may
further comprise an obscuring layer disposed so as to obscure the
absorbent layer. The apparatus may further comprise an obscuring
layer configured to at least partly visually obscure fluid within
the absorbent layer. The obscuring layer may comprise at least one
viewing window configured to allow a visual determination of the
saturation level of the absorbent layer. The viewing window may
comprise an array of dots.
[0042] In yet another embodiment, an apparatus for dressing a wound
for the application of topical negative pressure at a wound site,
comprises: [0043] a wound contact layer; [0044] an acquisition
distribution layer above the wound contact layer; [0045] an
absorbent layer over the acquisition distribution layer, the
absorbent layer comprising a matrix and superabsorbing particles
within the matrix; and [0046] a backing layer above the absorbent
layer.
[0047] Some embodiments of the apparatus may further comprise a
transmission layer between the wound contact layer and the
acquisition distribution layer. The acquisition distribution layer
may comprise viscose, polyester, polypropylene, cellulose,
polyethylene or a combination of some or all of these materials.
The absorbent layer may comprise between 30% and 40% (or between
about 30% and about 40%) cellulose matrix and between 60% and 70%
(or between about 60% and about 70%) superabsorbing polymers. The
backing layer may be transparent or translucent.
[0048] Some embodiments may further comprise an obscuring layer
between the absorbent layer and the backing layer. There may be one
or more viewing windows in the obscuring layer. At least the
obscuring layer may be shaped with a narrowed central portion along
its length. The obscuring layer may comprise two rows of three
viewing windows, one row of three viewing windows, one row of eight
viewing windows, two rows of five viewing windows, or one row of
five viewing windows. At least the obscuring layer may be shaped
with a narrowed central portion along both its width and its
length. The obscuring layer may comprise a 3.times.3 array of
viewing window or a quincunx array of viewing windows. In some
embodiments, at least the obscuring layer may comprise a six-lobed
shape. The absorbent layer and acquisition distribution layer may
be substantially the same shape as the obscuring layer. The
obscuring layer may further comprise a cross or maltese cross
shaped hole over which a fluidic connector for transmitting
negative pressure may be connected. The apparatus may further
comprise a fluidic connector configured to connect the backing
layer to a source of negative pressure.
[0049] In yet another embodiment, an apparatus for dressing a wound
for the application of topical negative pressure at a wound site,
comprises: [0050] an absorbent layer configured to retain fluid,
[0051] a backing layer above the absorbent layer, and [0052] an
obscuring layer configured to at least partly visually obscure
fluid within the absorbent layer, wherein the obscuring layer, in a
dry state, is configured to yield a color of Bg, gB, B, pB, bP, P,
rP, pPk, RP, O, rO, or yO on the CIE x, y chromaticity diagram.
[0053] Some embodiments may further comprise one or more viewing
windows in the backing layer. At least the obscuring layer may be
shaped with a narrowed central portion along its length. The
obscuring layer may comprise a 3.times.3 array of viewing window or
a quincunx array of viewing windows. In some embodiments, at least
the obscuring layer may comprise a six-lobed shape. The absorbent
layer and acquisition distribution layer may be substantially the
same shape as the obscuring layer. The obscuring layer may further
comprise a cross or maltese cross shaped hole over which a fluidic
connector for transmitting negative pressure may be connected. The
apparatus may further comprise a fluidic connector configured to
connect the backing layer to a source of negative pressure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0054] FIG. 1 illustrates an embodiment of a wound treatment
system;
[0055] FIGS. 2A-D illustrate the use and application of an
embodiment of a wound treatment system onto a patient;
[0056] FIG. 3A illustrates an embodiment of a wound dressing in
cross-section;
[0057] FIG. 3B illustrates another embodiment of a wound dressing
in cross-section;
[0058] FIG. 3C illustrates another embodiment of a wound dressing
in cross-section;
[0059] FIGS. 4A-C illustrate a top view of an embodiment of a wound
dressing with a narrow central portion;
[0060] FIGS. 5A-F-12A-F illustrate a perspective view, a top view,
a bottom view, a front view, a back view, and a side view,
respectively, of embodiments of a wound dressing including an
obscuring layer and viewing windows;
[0061] FIGS. 13A-B and 14 illustrate a top view of an embodiment of
a wound dressing including a cross-shaped viewing window;
[0062] FIGS. 15A-B illustrate a top view of an embodiment of a
wound dressing including slits in the wound dressing;
[0063] FIG. 16 illustrates an embodiment of a dressing comprising a
viewing window in the shape of a trademarked brand name;
[0064] FIG. 17 illustrates a top view of an embodiment of a
three-lobe configuration of a wound dressing and a dot pattern of
viewing windows;
[0065] FIG. 18 illustrates a top view of an embodiment of a
three-lobe configuration of a wound dressing and viewing windows in
the shape of a logo;
[0066] FIG. 19 illustrates a top view of an embodiment of a
three-lobe wound dressing;
[0067] FIG. 20 illustrates a top view of an embodiment of a
three-lobe wound dressing with flared ends on each lobe;
[0068] FIG. 21A illustrates a top view of an embodiment of a
four-lobe wound dressing with crescent shaped cut-outs as viewing
windows;
[0069] FIG. 21B illustrates a top view of an embodiment of a
four-lobe wound dressing with an array of dots at viewing
windows;
[0070] FIG. 21C illustrates a top view of an embodiment of a
four-lobe wound dressing with viewing windows;
[0071] FIG. 22 illustrates a perspective view of an embodiment of a
four-lobe wound dressing;
[0072] FIG. 23A-B illustrate embodiments of white and colored
fluidic connectors, respectively;
[0073] FIGS. 24A-F illustrate a perspective view, a top view, a
bottom view, a front view, a back view, and a side view,
respectively, of an embodiment of an oval-shaped wound
dressing;
[0074] FIGS. 25-32 illustrate embodiments of a wound dressing
including an obscuring layer and viewing windows including an
orifice viewing window;
[0075] FIGS. 33A-B illustrate embodiments of an oval-shaped wound
dressing comprising an obscuring layer and an orifice viewing
window;
[0076] FIG. 34A illustrates an exploded view of an embodiment of a
wound dressing connectable to a soft port;
[0077] FIG. 34B illustrates a cross sectional view of an embodiment
of a wound dressing;
[0078] FIG. 35 illustrates an exploded view of an embodiment of a
soft or flexible port for transmitting negative pressure to a wound
dressing;
[0079] FIG. 36 illustrates an embodiment of a soft port attached to
a wound dressing;
[0080] FIG. 37A illustrates a perspective view of a wound
dressing;
[0081] FIG. 37B illustrates a bottom view of the wound dressing of
FIG. 37A; and
[0082] FIG. 38 illustrates a CIE chromaticity scale.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0083] Embodiments disclosed herein relate to apparatuses and
methods of treating a wound with reduced pressure, including pump
and wound dressing components and apparatuses. The apparatuses and
components comprising the wound overlay and packing materials, if
any, are sometimes collectively referred to herein as
dressings.
[0084] 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 torn, 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, sterniotomies, fasciotomies, or other
conditions, dehisced wounds, acute wounds, chronic wounds, subacute
and dehisced wounds, traumatic wounds, flaps and skin grafts,
lacerations, abrasions, contusions, burns, diabetic ulcers,
pressure ulcers, stoma, surgical wounds, trauma and venous ulcers
or the like.
[0085] It will be understood that embodiments of the present
disclosure are generally applicable to use in topical negative
pressure ("TNP") therapy systems. Briefly, negative pressure wound
therapy assists in the closure and healing of many forms of "hard
to heal" wounds by reducing tissue oedema; encouraging blood flow
and granular tissue formation; removing excess exudate and may
reduce bacterial load (and thus infection risk). In addition, the
therapy allows for less disturbance of a wound leading to more
rapid healing. TNP therapy systems may also assist on the healing
of surgically closed wounds by removing fluid and by helping to
stabilize the tissue in the apposed position of closure. A further
beneficial use of TNP therapy can be found in grafts and flaps
where removal of excess fluid is important and close proximity of
the graft to tissue is required in order to ensure tissue
viability.
[0086] 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 inHg, 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).
[0087] 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 are 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 of wound closure
devices described here, increased wound contraction can lead to
increased tissue expansion in the surrounding wound tissue. This
effect may be increased by varying the force applied to the tissue,
for example by varying the negative pressure applied to the wound
over time, possibly in conjunction with increased tensile forces
applied to the wound via embodiments of the wound closure devices.
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.
[0088] Appendix 1 is a disclosure hereby incorporated by reference
and considered to be part of this specification which contains
embodiments that may be used in combination or in addition to the
embodiments described herein.
[0089] Appendix 2 is another application hereby incorporated by
reference and considered to be part of this specification which
contains embodiments that may be used in combination or in addition
to the embodiments described herein.
[0090] International Application PCT/GB2012/000587, titled "WOUND
DRESSING AND METHOD OF TREATMENT" and filed on Jul. 12, 2012, and
published as WO 2013/007973 A2 on Jan. 17, 2013, is an application,
hereby incorporated and considered to be part of this
specification, that is directed to embodiments, methods of
manufacture, and wound dressing components and wound treatment
apparatuses that may be used in combination or in addition to the
embodiments described herein. Additionally, embodiments of the
wound dressings, wound treatment apparatuses and methods described
herein may also be used in combination or in addition to those
described in U.S. Provisional Application Ser. No. 61/678,569,
filed Aug. 1, 2012, titled "WOUND DRESSING AND METHOD OF
TREATMENT," U.S. Provisional Application Ser. No. 61/650,904, filed
May 23, 2012, titled "APPARATUSES AND METHODS FOR NEGATIVE PRESSURE
WOUND THERAPY," U.S. Provisional Application Ser. No. 61/753,374,
filed Jan. 16, 2013, titled "WOUND DRESSING AND METHOD OF
TREATMENT," and U.S. Provisional Application Ser. No. 61/753,878,
filed Jan. 17, 2013, titled "WOUND DRESSING AND METHOD OF
TREATMENT," which are hereby incorporated by reference into this
present application in their entireties. Embodiments of the wound
dressings, wound treatment apparatuses and methods described herein
may also be used in combination or in addition to those described
in application Ser. No. 13/092,042, filed Apr. 21, 2011, published
as US2011/0282309, titled "WOUND DRESSING AND METHOD OF USE," and
which is hereby incorporated by reference in its entirety,
including further details relating to embodiments of wound
dressings, the wound dressing components and principles, and the
materials used for the wound dressings.
[0091] FIG. 1 illustrates an embodiment of a TNP wound treatment
system 100 comprising a wound dressing 110 in combination with a
pump 150. As stated above, the wound dressing 110 can be any wound
dressing embodiment disclosed herein including without limitation
dressing embodiment or have any combination of features of any
number of wound dressing embodiments disclosed herein. Here, the
dressing 110 may be placed over a wound as described previously,
and a conduit 130 may then be connected to the port 120, although
in some embodiments the dressing 101 may be provided with at least
a portion of the conduit 130 preattached to the port 120.
Preferably, the dressing 110 is provided as a single article with
all wound dressing elements (including the port 120) pre-attached
and integrated into a single unit. The wound dressing 110 may then
be connected, via the conduit 130, to a source of negative pressure
such as the pump 150. The pump 150 can be miniaturized and
portable, although larger conventional pumps may also be used with
the dressing 110. In some embodiments, the pump 150 may be attached
or mounted onto or adjacent the dressing 110. A connector 140 may
also be provided so as to permit the conduit 130 leading to the
wound dressing 110 to be disconnected from the pump, which may be
useful for example during dressing changes.
[0092] FIGS. 2A-D illustrate the use of an embodiment of a TNP
wound treatment system being used to treat a wound site on a
patient. FIG. 2A shows a wound site 200 being cleaned and prepared
for treatment. Here, the healthy skin surrounding the wound site
200 is preferably cleaned and excess hair removed or shaved. The
wound site 200 may also be irrigated with sterile saline solution
if necessary. Optionally, a skin protectant may be applied to the
skin surrounding the wound site 200. If necessary, a wound packing
material, such as foam or gauze, may be placed in the wound site
200. This may be preferable if the wound site 200 is a deeper
wound.
[0093] After the skin surrounding the wound site 200 is dry, and
with reference now to FIG. 2B, the wound dressing 110 may be
positioned and placed over the wound site 200. Preferably, the
wound dressing 110 is placed with the wound contact layer 2102 over
and/or in contact with the wound site 200. 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 110 over the wound site 200. Preferably, the
dressing 110 is positioned such that the port 2150 is in a raised
position with respect to the remainder of the dressing 110 so as to
avoid fluid pooling around the port. In some embodiments, the
dressing 110 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 TNP, the edges of
the dressing 110 are preferably smoothed over to avoid creases or
folds.
[0094] With reference now to FIG. 2C, the dressing 110 is connected
to the pump 150. The pump 150 is configured to apply negative
pressure to the wound site via the dressing 110, and typically
through a conduit. In some embodiments, and as described above in
FIG. 1, a connector may be used to join the conduit from the
dressing 110 to the pump 150. Upon the application of negative
pressure with the pump 150, the dressing 110 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 110. In some embodiments, the pump 150 may be
configured to detect if any leaks are present in the dressing 110,
such as at the interface between the dressing 110 and the skin
surrounding the wound site 200. Should a leak be found, such leak
is preferably remedied prior to continuing treatment.
[0095] Turning to FIG. 2D, additional fixation strips 210 may also
be attached around the edges of the dressing 110. Such fixation
strips 210 may be advantageous in some situations so as to provide
additional sealing against the skin of the patient surrounding the
wound site 200. For example, the fixation strips 210 may provide
additional sealing for when a patient is more mobile. In some
cases, the fixation strips 210 may be used prior to activation of
the pump 150, particularly if the dressing 110 is placed over a
difficult to reach or contoured area.
[0096] Treatment of the wound site 200 preferably continues until
the wound has reached a desired level of healing. In some
embodiments, it may be desirable to replace the dressing 110 after
a certain time period has elapsed, or if the dressing is full of
wound fluids. During such changes, the pump 150 may be kept, with
just the dressing 110 being changed.
[0097] FIGS. 3A-C illustrate cross-sections through a wound
dressing 2100 similar to the wound dressing of FIG. 1 according to
an embodiment of the disclosure. A view from above the wound
dressing 2100 is illustrated in FIG. 1 with the line A-A indicating
the location of the cross-section shown in FIGS. 3A and 3B. The
wound dressing 2100, which can alternatively be any wound dressing
embodiment disclosed herein including without limitation wound
dressing 110 or any combination of features of any number of wound
dressing embodiments disclosed herein, can be located over a wound
site to be treated. The dressing 2100 may be placed to as to form a
sealed cavity over the wound site. In a preferred embodiment, the
dressing 2100 comprises a backing layer 2140 attached to a wound
contact layer 2102, both of which are described in greater detail
below. These two layers 2140, 2102 are preferably joined or sealed
together so as to define an interior space or chamber. This
interior space or chamber may comprise additional structures that
may be adapted to distribute or transmit negative pressure, store
wound exudate and other fluids removed from the wound, and other
functions which will be explained in greater detail below. Examples
of such structures, described below, include a transmission layer
2105 and an absorbent layer 2110.
[0098] As illustrated in FIGS. 3A-C, a lower surface 2101 of the
wound dressing 2100 may be provided with an optional wound contact
layer 2102. The wound contact layer 2102 can be a polyurethane
layer or polyethylene layer or other flexible layer which is
perforated, for example via a hot pin process, laser ablation
process, ultrasound process or in some other way or otherwise made
permeable to liquid and gas. The wound contact layer 2102 has a
lower surface 2101 and an upper surface 2103. The perforations 2104
preferably comprise through holes in the wound contact layer 2102
which enable fluid to flow through the layer 2102. The wound
contact layer 2102 helps prevent tissue ingrowth into the other
material of the wound dressing. Preferably, the perforations are
small enough to meet this requirement while still allowing fluid to
flow therethrough. For example, perforations formed as slits or
holes having a size ranging from 0.025 mm to 1.2 mm are considered
small enough to help prevent tissue ingrowth into the wound
dressing while allowing wound exudate to flow into the dressing. In
some configurations, the wound contact layer 2102 may help maintain
the integrity of the entire dressing 2100 while also creating an
air tight seal around the absorbent pad in order to maintain
negative pressure at the wound.
[0099] Some embodiments of the wound contact layer 2102 may also
act as a carrier for an optional lower and upper adhesive layer
(not shown). For example, a lower pressure sensitive adhesive may
be provided on the lower surface 2101 of the wound dressing 2100
whilst an upper pressure sensitive adhesive layer may be provided
on the upper surface 2103 of the wound contact layer. The pressure
sensitive adhesive, which may be a silicone, hot melt, hydrocolloid
or acrylic based adhesive or other such adhesives, may be formed on
both sides or optionally on a selected one or none of the sides of
the wound contact layer. When a lower pressure sensitive adhesive
layer is utilized may be helpful to adhere the wound dressing 2100
to the skin around a wound site. In some embodiments, the wound
contact layer may comprise perforated polyurethane film. The lower
surface of the film may be provided with a silicone pressure
sensitive adhesive and the upper surface may be provided with an
acrylic pressure sensitive adhesive, which may help the dressing
maintain its integrity. In some embodiments, a polyurethane film
layer may be provided with an adhesive layer on both its upper
surface and lower surface, and all three layers may be perforated
together.
[0100] A layer 2105 of porous material can be located above the
wound contact layer 2102. This porous layer, or transmission layer,
2105 allows transmission of fluid including liquid and gas away
from a wound site into upper layers of the wound dressing. In
particular, the transmission layer 2105 preferably ensures that an
open air channel can be maintained to communicate negative pressure
over the wound area even when the absorbent layer has absorbed
substantial amounts of exudates. The layer 2105 should preferably
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. The layer
2105 may be formed of a material having a three dimensional
structure. For example, a knitted or woven spacer fabric (for
example Baltex 7970 weft knitted polyester) or a non-woven fabric
could be used.
[0101] A layer 2110 of absorbent material is provided above the
transmission layer 2105. The absorbent material, which comprise a
foam or non-woven natural or synthetic material, and which may
optionally comprise a super-absorbent material, forms a reservoir
for fluid, particularly liquid, removed from the wound site. In
some embodiments, the layer 2100 may also aid in drawing fluids
towards the backing layer 2140.
[0102] With reference to FIGS. 3A-C, a masking or obscuring layer
2107 can be positioned beneath at least a portion of the backing
layer 2140. In some embodiments, the obscuring layer 2107 can have
any of the same features, materials, or other details of any of the
other embodiments of the obscuring layers disclosed herein,
including but not limited to having any viewing windows or holes.
Additionally, the obscuring layer 2107 can be positioned adjacent
to the backing layer, or can be positioned adjacent to any other
dressing layer desired. In some embodiments, the obscuring layer
2107 can be adhered to or integrally formed with the backing layer.
Preferably, the obscuring layer 2107 is configured to have
approximately the same size and shape as the absorbent layer 2110
so as to overlay it. As such, in these embodiments the obscuring
layer 2107 will be of a smaller area than the backing layer
2140.
[0103] The material of the absorbent layer 2110 may also prevent
liquid collected in the wound dressing 2100 from flowing freely
within the dressing, and preferably acts so as to contain any
liquid collected within the absorbent layer 2110. The absorbent
layer 2110 also helps distribute fluid throughout the layer via a
wicking action so that fluid is drawn from the wound site and
stored throughout the absorbent layer. This helps prevent
agglomeration in areas of the absorbent layer. The capacity of the
absorbent material must be sufficient to manage the exudates flow
rate of a wound when negative pressure is applied. Since in use the
absorbent layer experiences negative pressures the material of the
absorbent layer is chosen to absorb liquid under such
circumstances. A number of materials exist that are able to absorb
liquid when under negative pressure, for example superabsorber
material. The absorbent layer 2110 may typically be manufactured
from ALLEVYN.TM. foam, Freudenberg 114-224-4 and/or
ChemPosite.TM.11C-450. In some embodiments, the absorbent layer
2110 may comprise a composite comprising superabsorbent powder,
fibrous material such as cellulose, and bonding fibers. In a
preferred embodiment, the composite is an airlaid, thermally-bonded
composite.
[0104] An orifice 2145 is preferably provided in the backing layer
2140 to allow a negative pressure to be applied to the dressing
2100. A suction port 2150 is preferably attached or sealed to the
top of the backing layer 2140 over an orifice 2145 made into the
dressing 2100, and communicates negative pressure through the
orifice 2145. A length of tubing 2220 may be coupled at a first end
to the suction port 2150 and at a second end to a pump unit (not
shown) to allow fluids to be pumped out of the dressing. The port
may be adhered and sealed to the backing layer 2140 using an
adhesive such as an acrylic, cyanoacrylate, epoxy, UV curable or
hot melt adhesive. The port 2150 is formed from a soft polymer, for
example a polyethylene, a polyvinyl chloride, a silicone or
polyurethane having a hardness of 30 to 90 on the Shore A scale. In
some embodiments, the port 2150 may be made from a soft or
conformable material, for example using the embodiments described
below in FIGS. 23A-B.
[0105] Preferably the absorbent layer 2110 and the obscuring layer
2107 include at least one through hole 2146 located so as to
underlie the port 2150. The through hole 2146, while illustrated
here as being larger than the hole through the obscuring layer 2107
and backing layer 2140, may in some embodiments be bigger or
smaller than either. Of course, the respective holes through these
various layers 2107, 2140, and 2110 may be of different sizes with
respect to each other. As illustrated in FIGS. 3A-C a single
through hole can be used to produce an opening underlying the port
2150. It will be appreciated that multiple openings could
alternatively be utilized. Additionally should more than one port
be utilized according to certain embodiments of the present
disclosure one or multiple openings may be made in the absorbent
layer and the obscuring layer in registration with each respective
port. Although not essential to certain embodiments of the present
disclosure the use of through holes in the super-absorbent layer
may provide a fluid flow pathway which remains unblocked in
particular when the absorbent layer 2100 is near saturation.
[0106] The aperture or through-hole 2146 is preferably provided in
the absorbent layer 2110 and the obscuring layer 2107 beneath the
orifice 2145 such that the orifice is connected directly to the
transmission layer 2105. This allows the negative pressure applied
to the port 2150 to be communicated to the transmission layer 2105
without passing through the absorbent layer 2110. This ensures that
the negative pressure applied to the wound site is not inhibited by
the absorbent layer as it absorbs wound exudates. In other
embodiments, no aperture may be provided in the absorbent layer
2110 and/or the obscuring layer 2107, or alternatively a plurality
of apertures underlying the orifice 2145 may be provided.
[0107] The backing layer 2140 is preferably gas impermeable, but
moisture vapor permeable, and can extend across the width of the
wound dressing 2100. The backing layer 2140, which may for example
be a polyurethane film (for example, Elastollan SP9109) having a
pressure sensitive adhesive on one side, is impermeable to gas and
this layer thus operates to cover the wound and to seal a wound
cavity over which the wound dressing is placed. In this way an
effective chamber is made between the backing layer 2140 and a
wound site where a negative pressure can be established. The
backing layer 2140 is preferably sealed to the wound contact layer
2102 in a border region 2200 around the circumference of the
dressing, ensuring that no air is drawn in through the border area,
for example via adhesive or welding techniques. The backing layer
2140 protects the wound from external bacterial contamination
(bacterial barrier) and allows liquid from wound exudates to be
transferred through the layer and evaporated from the film outer
surface. The backing layer 2140 preferably comprises two layers; a
polyurethane film and an adhesive pattern spread onto the film. The
polyurethane film is preferably moisture vapor permeable and may be
manufactured from a material that has an increased water
transmission rate when wet.
[0108] The absorbent layer 2110 may be of a greater area than the
transmission layer 2105, such that the absorbent layer overlaps the
edges of the transmission layer 2105, thereby ensuring that the
transmission layer does not contact the backing layer 2140. This
provides an outer channel 2115 of the absorbent layer 2110 that is
in direct contact with the wound contact layer 2102, which aids
more rapid absorption of exudates to the absorbent layer.
Furthermore, this outer channel 2115 ensures that no liquid is able
to pool around the circumference of the wound cavity, which may
otherwise seep through the seal around the perimeter of the
dressing leading to the formation of leaks.
[0109] As shown in FIG. 3A, one embodiment of the wound dressing
2100 comprises an aperture 2146 in the absorbent layer 2110
situated underneath the port 2150. In use, for example when
negative pressure is applied to the dressing 2100, a wound facing
portion of the port 150 may thus come into contact with the
transmission layer 2105, which can thus aid in transmitting
negative pressure to the wound site even when the absorbent layer
2110 is filled with wound fluids. Some embodiments may have the
backing layer 2140 be at least partly adhered to the transmission
layer 2105. In some embodiments, the aperture 2146 is at least 1-2
mm larger than the diameter of the wound facing portion of the port
2150, or the orifice 2145.
[0110] A filter element 2130 that is impermeable to liquids, but
permeable to gases is provided to act as a liquid barrier, and to
ensure that no liquids are able to escape from the wound dressing.
The filter element may also function as a bacterial barrier.
Typically the pore size is 0.2 .mu.m. Suitable materials for the
filter material of the filter element 2130 include 0.2 micron
Gore.TM. expanded PTFE from the MMT range, PALL Versapore.TM. 200R,
and Donaldson.TM. TX6628. Larger pore sizes can also be used but
these may require a secondary filter layer to ensure full bioburden
containment. As wound fluid contains lipids it is preferable,
though not essential, to use an oleophobic filter membrane for
example 1.0 micron MMT-332 prior to 0.2 micron MMT-323. This
prevents the lipids from blocking the hydrophobic filter. The
filter element can be attached or sealed to the port and/or the
backing layer 2140 over the orifice 2145. For example, the filter
element 2130 may be molded into the port 2150, or may be adhered to
both the top of the backing layer 2140 and bottom of the port 2150
using an adhesive such as, but not limited to, a UV cured
adhesive.
[0111] In FIG. 3B, an embodiment of the wound dressing 2100 is
illustrated which comprises spacer elements 2152, 2153 in
conjunction with the port 2150 and the filter 2130. With the
addition of such spacer elements 2152, 2153, the port 2150 and
filter 2130 may be supported out of direct contact with the
absorbent layer 2110 and/or the transmission layer 2105. The
absorbent layer 2110 may also act as an additional spacer element
to keep the filter 2130 from contacting the transmission layer
2105. Accordingly, with such a configuration contact of the filter
2130 with the transmission layer 2105 and wound fluids during use
may thus be minimized. As contrasted with the embodiment
illustrated in FIG. 3A, the aperture 2146 through the absorbent
layer 2110 and the obscuring layer 2107 may not necessarily need to
be as large or larger than the port 2150, and would thus only need
to be large enough such that an air path can be maintained from the
port to the transmission layer 2105 when the absorbent layer 2110
is saturated with wound fluids.
[0112] With reference now to FIG. 3C, which shares many of the
elements illustrated in FIGS. 3A-C, the embodiment illustrated here
comprises the backing layer 2140, masking layer 2107, and absorbent
layer 2110, all of which have a cut or opening made therethrough
which communicate directly to the transmission layer 2105 so as to
form the orifice 2145. The suction port 2150 is preferably situated
above it and communicates with the orifice 2145.
[0113] In particular for embodiments with a single port 2150 and
through hole, it may be preferable for the port 2150 and through
hole to be located in an off-center position as illustrated in
FIGS. 3A-C and in FIG. 1. 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 2130 may be less likely to
come into contact with wound fluids that could prematurely occlude
the filter 2130 so as to impair the transmission of negative
pressure to the wound site.
[0114] FIGS. 4A-C illustrate embodiments of wound dressings 300
similar to the embodiments described above and provided with a
narrowed central portion in various lengths and widths. FIG. 4A
illustrates an embodiment of a wound dressing 300 with a narrowed
central portion or a waisted middle portion. The wound dressing 300
has a backing layer 301. The backing layer 301 can have a
rectangular or square shaped perimeter and can be a transparent or
translucent material. The backing layer 301 can have a lower
surface 305 and an upper surface 306. The lower surface of the
backing layer 301 can be configured to be placed on the skin
surface surrounding the wound site as discussed previously with
reference to FIGS. 3A-C. Additionally, the lower surface 305 can
have a wound contact layer. The wound contact layer can have all
the features and embodiments described herein, including without
limitation wound dressing embodiments described in reference to
FIGS. 3A-C. The wound contact layer can be adhered to the perimeter
of the lower surface 305 of the backing layer 301. The wound
contact layer can comprise an adhesive or any other method of
attachment that allows attachment of the wound dressing to the skin
surface as previously described.
[0115] In some embodiments, the wound dressing 300 can have a port
304 offset from the center of the dressing as described previously.
The port 304 can be a domed port or a soft fluidic connector
(described in detail below). Although the port 304 can be placed in
a central location on the dressing, it is preferably offset from
the center of the dressing to a particular side or edge. As such,
the orientation of the port 304, when placed on the body, may thus
permit the port 304 to be situated in an elevated position, thereby
increasing the amount of time that the dressing 300 may be used
before coming into contact with fluids. Although other orientations
may be used, and may occur in practice (e.g., when the patient
shifts positions), placing the port 304 at a lower position may
cause the filter proximate the port (not illustrated here) to
become saturated, which may cause the dressing to need changing
even though there may still remain some absorptive capacity within
the absorbent layer. Preferably, the port 304 has an orifice for
the connection of a tube or conduit thereto; this orifice may be
angled away from the center of the dressing 300 so as to permit the
tube or conduit to extend away from the dressing 300. In some
preferred embodiments, the port 304 comprises an orifice that
permits the tube or conduit inserted therein to be approximately
parallel to the top surface of the backing layer 301.
[0116] In various embodiments, the wound dressing 300 can have an
absorbent material 302. The absorbent material 302 can be
accompanied by the additional components within the wound dressing
as described with reference to the wound dressing cross-section in
FIG. 3A-B, such as a transmission layer and a masking or obscuring
layer (not shown).
[0117] In some embodiments, the wound dressing 300 can have an
absorbent material 302 with a central portion 308. The absorbent
material 302 can have a longitudinal length and a transverse width.
In some embodiments, the longitudinal length is greater than the
transverse width. In some embodiments, the longitudinal length and
the transverse width are of equal size. In various embodiments, the
absorbent material 302 can have a contoured shape with a
substantially rectangular body.
[0118] The central portion 308 of the absorbent material 302 may
comprise a waisted portion 303. The waisted portion 303 can be
defined by the transverse width of the absorbent material 302
narrowing at the central portion 308 of the longitudinal length.
For example, in some embodiments, the waisted portion 303 can be a
narrow width at the central portion 308 of the absorbent material
302, as illustrated in FIGS. 4A-C. Additional embodiments of the
waisted portion 303 are possible including those described herein.
Further, the shape of the accompanying components within the wound
dressing as described with reference to FIGS. 3A-C can be formed to
the same contoured shape of the absorbent material including the
waisted portion.
[0119] The waisted portion 303 can increase the flexibility of the
wound dressing and can allow enhanced compatibility of the wound
dressing to the patient's body. For example, the narrow central
region may allow for improved contact and adhesion of the wound
dressing to the skin surface when the wound dressing is used on
non-planar surfaces and/or wrapped around an arm or leg. Further,
the narrow central portion provides increased compatibility with
the patient's body and patient movement.
[0120] As in FIGS. 15A-B, embodiments of wound dressings may
comprise various configurations of slits (described in detail
below) so as to further enhance conformability of the dressing in
non-planar wounds. Also, as described below, the absorbent layers
may be colored or obscured with an obscuring layer, and optionally
provided with one or more viewing windows. The domed ports may also
be replaced with one or more fluidic connectors of the type
described below in FIGS. 23A-B. Further, the wound dressing 300 can
comprise all designs or embodiments herein described or have any
combination of features of any number of wound dressing embodiments
disclosed herein.
[0121] FIG. 4B illustrates an embodiment of a wound dressing 300
with a waisted portion. A wound dressing 300 as illustrated in FIG.
4B can have the features and embodiments as described above with
reference to FIG. 4A. However, FIG. 4B illustrates an embodiment
with a shorter longitudinal length with respect to the transverse
width. FIG. 4C illustrates an additional embodiment of a wound
dressing 300 with a waisted portion. As illustrated in FIG. 4C, the
wound dressing can have a longitudinal length and a transverse
width that are not substantially different in size, as opposed to a
longitudinal length that is substantially longer than the
transverse width of the wound dressing as shown in the embodiments
illustrated in FIGS. 4A and 4B. The embodiments of a wound dressing
illustrated in FIGS. 4B and 4C can include all features and
embodiments described herein for wound dressings including those
embodiments of the waisted portion 303 described with reference to
FIG. 4A.
[0122] FIGS. 5A-F, 6A-F, 7A-F, 8A-F, 9A-F, 10A-F, 11A-F, 12A-F, and
24 illustrate additional embodiments of wound dressings. In these
embodiments, a waisted portion 408 is located inwardly with
reference to an edge 409 of the absorbent layer 402. Preferably,
the contour of the absorbent layer 402 is curved from the edge 409
to the waisted portion 408, so as to form a smooth contour.
[0123] FIGS. 5A-F illustrate multiple views of an embodiment of a
wound dressing with a waisted portion, obscuring layer, and viewing
windows. FIG. 5A illustrates a perspective view of an embodiment of
a wound dressing 400. The wound dressing 400 preferably comprises a
port 406. The port 406 is preferably configured to be in fluid
communication with a pump as described with reference to FIG. 1,
and may include a tube or conduit pre-attached to the port.
Alternatively, negative pressure can be supplied to the wound
dressing through other suitable fluidic connectors, including but
not limited to the fluidic connectors of the type described below
in FIGS. 23A-B.
[0124] The wound dressing 400 can be constructed similar to the
embodiments of FIGS. 3A and 3B above, and may comprise an absorbent
material 402 underneath or within a backing layer 405. Optionally,
a wound contact layer and a transmission layer may also be provided
as part of the wound dressing 400 as described above. The absorbent
material 402 can contain a narrowed central or waisted portion 408,
as described previously to increase flexibility and conformability
of the wound dressing to the skin surface. The backing layer 405
may have a border region 401 that extends beyond the periphery of
the absorbent material 402. The backing layer 405 may be a
translucent or transparent backing layer, such that the border
region 401 created from the backing layer 405 can be translucent or
transparent. The area of the border region 401 of the backing layer
405 can be approximately equal around the perimeter of the entire
dressing with the exception of the narrowed central portion, where
the area of the border region is larger. One will recognize that
the size of the border region 401 will depend on the full
dimensions of the dressing and any other design choices.
[0125] As illustrated in FIG. 5A, provided at least at the top of
or over the absorbent layer 402 and under the backing layer 405 may
be an obscuring layer 404 that optionally has one or more viewing
windows 403. The obscuring layer 404 may partially or completely
obscure contents (such as fluids) contained within the wound
dressing 400 and/or the absorbent material (i.e., within the
absorbent material 402 or under the backing layer 405). The
obscuring layer may be a colored portion of the absorbent material,
or may be a separate layer that covers the absorbent material. In
some embodiments, the absorbent material 402 may be hidden
(partially or completely), colored, or tinted, via the obscuring
layer 404, so as to provide cosmetic and/or aesthetic enhancements,
in a similar manner to what is described above. The obscuring layer
is preferably provided between the topmost backing layer 405 and
the absorbent material 402, although other configurations are
possible. The cross-sectional view in FIGS. 3A and B illustrates
this arrangement with respect to the masking or obscuring layer
2107. Other layers and other wound dressing components can be
incorporated into the dressing as herein described.
[0126] The obscuring layer 404 can be positioned at least partially
over the absorbent material 402. In some embodiments, the obscuring
layer 404 can be positioned adjacent to the backing layer, or can
be positioned adjacent to any other dressing layer desired. In some
embodiments, the obscuring layer 404 can be adhered to or
integrally formed with the backing layer and/or the absorbent
material.
[0127] As illustrated in FIG. 5A, the obscuring layer 404 can have
substantially the same perimeter shape and size as the absorbent
material 402. The obscuring layer 404 and absorbent material 402
can be of equal size so that the entirety of the absorbent material
402 can be obscured by the obscuring layer 404. The obscuring layer
404 may allow for obscuring of wound exudate, blood, or other
matter released from a wound. Further, the obscuring layer 404 can
be completely or partially opaque having cut-out viewing windows or
perforations.
[0128] In some embodiments, the obscuring layer 404 can help to
reduce the unsightly appearance of a dressing during use, by using
materials that impart partial obscuring or masking of the dressing
surface. The obscuring layer 404 in one embodiment only partially
obscures the dressing, to allow clinicians to access the
information they require by observing the spread of exudate across
the dressing surface. The partial masking nature of this embodiment
of the obscuring layer enables a skilled clinician to perceive a
different color caused by exudate, blood, by-products etc. in the
dressing allowing for a visual assessment and monitoring of the
extent of spread across the dressing. However, since the change in
color of the dressing from its clean state to a state containing
exudate is only a slight change, the patient is unlikely to notice
any aesthetic difference. Reducing or eliminating a visual
indicator of wound exudate from a patient's wound is likely to have
a positive effect on their health, reducing stress for example.
[0129] In some embodiments, the obscuring layer can be formed from
a non-woven fabric (for example, polypropylene), and may be
thermally bonded using a diamond pattern with 19% bond area. In
various embodiments, the obscuring layer can be hydrophobic or
hydrophilic. Depending on the application, in some embodiments, a
hydrophilic obscuring layer may provide added moisture vapor
permeability. In some embodiments, however, hydrophobic obscuring
layers may still provide sufficient moisture vapor permeability
(i.e., through appropriate material selection, thickness of the
obscuring layer), while also permitting better retention of dye or
color in the obscuring layer. As such, dye or color may be trapped
beneath the obscuring layer. In some embodiments, this may permit
the obscuring layer to be colored in lighter colors or in white. In
the preferred embodiment, the obscuring layer is hydrophobic. In
some embodiments, the obscuring layer material can be sterilizable
using ethylene oxide. Other embodiments may be sterilized using
gamma irradiation, an electron beam, steam or other alternative
sterilization methods. Additionally, in various embodiments the
obscuring layer can colored or pigmented, e.g., in medical blue.
The obscuring layer may also be constructed from multiple layers,
including a colored layer laminated or fused to a stronger
uncolored layer. Preferably, the obscuring layer is odorless and
exhibits minimal shedding of fibers.
[0130] The absorbent layer 402, itself may be colored or tinted in
some embodiments, however, so that an obscuring layer is not
necessary. The dressing may optionally include a means of partially
obscuring the top surface. This could also be achieved using a
textile (knitted, woven, or non-woven) layer without openings,
provided it still enables fluid evaporation from the absorbent
structure. It could also be achieved by printing an obscuring
pattern on the top film, or on the top surface of the uppermost pad
component, using an appropriate ink or colored pad component (yarn,
thread, coating) respectively. Another way of achieving this would
be to have a completely opaque top surface, which could be
temporarily opened by the clinician for inspection of the dressing
state (for example through a window), and closed again without
compromising the environment of the wound.
[0131] Additionally, FIG. 5A illustrates an embodiment of the wound
dressing including one or more viewing windows 403. The one or more
viewing windows 403 preferably extend through the obscuring layer
404. These viewing windows 403 may allow visualization by a
clinician or patient of the wound exudate in the absorbent material
below the obscuring layer. FIG. 5A illustrates an array of dots
(e.g., in one or more parallel rows) that can serve as viewing
windows 403 in the obscuring layer 404 of the wound dressing. In a
preferred embodiment, two or more viewing windows 403 may be
parallel with one or more sides of the dressing 400. In some
embodiments, the one or more viewing windows may measure between
0.1 mm and 20 mm, preferably 0.4 mm to 10 mm, and even more
preferably, 1 mm to 4 mm.
[0132] The viewing windows 403 may be cut through the obscuring
layer 404 or may be part of an uncolored area of the obscuring
layer 404 and therefore may allow visualization of the absorbent
material 402. The one or more viewing windows 403 can be arranged
in a repeating pattern across the obscuring layer 404 or can be
arranged at random across the obscuring layer. Additionally, the
one or more viewing windows can be a circular shape or dots.
Preferably, the one or more viewing windows 403 are configured so
as to permit not only the degree of saturation, but also the
progression or spread of fluid toward the fluid port 406, as in
some embodiments, dressing performance may be adversely affected
when the level of fluid has saturated the fluid proximate the port
406. In some embodiments, a "starburst" array of viewing windows
403 emanating around the port 406 may be suitable to show this
progression, although of course other configurations are
possible.
[0133] In FIG. 5A, the viewing windows 403 correspond to the area
of the absorbent material 402 that is not covered by the obscuring
layer 404. As such, the absorbent material 402 is directly adjacent
the backing layer 405 in this area. Since the obscuring layer 404
acts as a partial obscuring layer, the viewing windows 403 may be
used by a clinician or other trained user to assess the spread of
wound exudate throughout the dressing. In some embodiments, the
viewing windows 403 can comprise an array of dots or crescent
shaped cut-outs. For example, an array of dots as viewing windows
403 are illustrated in FIGS. 5A-F, 6A-F, 7A-F, 8A-F, 9A-F, 10A-F,
11A-F, and 12A-F in which the array of dots are arranged in an
5.times.2, 3.times.2, 8.times.1, 5.times.1, 3.times.1, 3.times.3,
3.times.3, and quincunx array respectively. Additionally, in some
embodiments, the dot pattern can be distributed evenly throughout
the obscuring layer and across the entire or substantially the
entire surface of the obscuring layer. In some embodiments, the
viewing windows 403 may be distributed randomly throughout the
obscuring layer. Preferably, the area of the obscuring layer 404
uncovered by the one or more viewing windows 403 is balanced to as
to minimize the appearance of exudate while permitting the
inspection of the dressing 400 and/or absorbent material 402. In
some embodiments, the area exposed by the one or more viewing
windows 403 does not exceed 20% of the area of the obscuring layer
404, preferably 10%, and even more preferably 5%.
[0134] The viewing windows 403 may take several configurations, as
will be discussed in relation to FIGS. 16-18. In FIG. 17, the
viewing windows 403 may comprise an array of regularly spaced
uncolored dots (holes) made into the obscuring layer 404. While the
dots illustrated here are in a particular pattern, the dots may be
arranged in different configurations, or at random. The viewing
windows 403 are preferably configured so as to permit a patient or
caregiver to ascertain the status of the absorbent layer, in
particular to determine its saturation level, as well as the color
of the exudate (e.g., whether excessive blood is present). By
having one or more viewing windows, the status of the absorbent
layer can be determined in an unobtrusive manner that is not
aesthetically unpleasing to a patient. Because a large portion of
the absorbent layer may be obscured, the total amount of exudate
may therefore be hidden. As such, the status and saturation level
of the absorbent layer 402 may therefore present a more discreet
external appearance so as to reduce patient embarrassment and
visibility and thereby enhance patient comfort. In some
configurations, the one or more viewing windows 403 may be used to
provide a numerical assessment of the degree of saturation of the
dressing 400. This may be done electronically (e.g., via a digital
photograph assessment), or manually. For example, the degree of
saturation may be monitored by counting the number of viewing
windows 403 which may be obscured or tinted by exudate or other
wound fluids.
[0135] In some embodiments, the absorbent layer 402 or the
obscuring layer 404, in particular the colored portion of the
absorbent layer, may comprise (or be colored because of) the
presence of an auxiliary compound. The auxiliary compound may in
some embodiments be activated charcoal, which can act to absorb
odors. The use of antimicrobial, antifungal, anti-inflammatory, and
other such therapeutic compounds is also possible. In some
embodiments, the color may change as a function of time (e.g., to
indicate when the dressing needs to be changed), if the dressing is
saturated, or if the dressing has absorbed a certain amount of a
harmful substance (e.g., to indicate the presence of infectious
agents). In some embodiments, the one or more viewing windows 403
may be monitored electronically, and may be used in conjunction
with a computer program or system to alert a patient or physician
to the saturation level of the dressing 400.
[0136] FIG. 16 illustrates an embodiment of a dressing containing a
viewing window in the shape of a trademarked brand name ("PICO").
FIG. 18 illustrates an embodiment of a dressing comprising a
viewing window in the shape of a logo, here, the Smith & Nephew
logo. Of course, many other configurations are possible, including
other graphics, texts, or designs. The graphical or textual
elements present in the viewing window may also be, for example,
instructional in nature.
[0137] In other alternatives, instructions may be given to change
the wound dressing when the exudate reaches a predetermined
distance from the edge of the wound dressing, such as 5 mm from the
wound dressing edge or 7 mm from the wound dressing edge, etc.
Alternatively a `traffic light` system may be implemented whereby
an electronic indicator shows green, amber or red light to indicate
the spread of exudate in the wound dressing. Alternatively or
additionally, another suitable indicator may be used for indicating
the spread of exudate over the dressing.
[0138] FIGS. 5A-F illustrate multiple views of the wound dressing
400. FIG. 5A illustrates a perspective view of a wound dressing
with the dimensions of 300 mm.times.150 mm. FIGS. 5B and 5C
illustrate a top view and bottom view of the embodiment of a wound
dressing described in FIG. 5A. FIGS. 5D and 5E illustrate a front
and back view respectively of the wound dressing 400 described in
FIG. 5A. FIG. 5F illustrates a side view of the wound dressing as
described in FIG. 5A.
[0139] Embodiments of the wound dressings described herein may be
arranged such that each embodiment may have enhanced compatibility
with body movement. This can be achieved by using a different shape
for different wound types or areas of the body. Wound dressing
embodiments can be of any suitable shape or form or size as
illustrated in FIGS. 5A-F, 6A-F, 7A-F, 8A-F, 9A-F, 10A-F, 11A-F,
12A-F, and 24A-F. The overall dimensions of the dressings as
illustrated in FIGS. 5A-F, 6A-F, 7A-F, 8A-F, 9A-F, 10A-F, 11A-F,
12A-F may be, for example but without limitation, 300 mm.times.150
mm, 200 mm.times.150 mm, 400 mm.times.100 mm, 300 mm.times.100 mm,
200 mm.times.100 mm, 250 mm.times.250 mm, 200 mm.times.200 mm, and
150 mm.times.150 mm, respectively, although any total size may be
used, and the size may be determined to match particular wound
sizes. The oval-shaped dressing in FIGS. 24A-F may, in some
embodiments, measure 190 mm.times.230 mm, or 145.5 mm.times.190 mm.
Again, it will be understood that the embodiments described in the
foregoing are simply illustrative embodiments illustrating possible
sizes, dimensions, and configurations of wound dressings, and that
other configurations are possible.
[0140] As noted above, the preceding embodiments illustrated in
FIGS. 5A-F, 6A-F, 7A-F, 8A-F, 9A-F, 10A-F, 11A-F and 12A-F may
comprise a waisted portion 408 located inwardly with reference to
an edge 409 of the absorbent layer 402. The contour of the
absorbent layer to the waisted portion 408 is preferably rounded
and smooth. In the embodiments of FIGS. 5A-F, 6A-F, 7A-F, 8A-F, and
9A-F, the inward distance between the edge 409 and the waisted
portion 408 may range from 1 mm, 5 mm, 10 mm, 15 mm, 20 mm, and 30
mm. Preferably, the inward distance is 10 mm. In the embodiments of
FIGS. 10A-F, 11A-F, and 12A-F the inward distance between the edge
409 and the waisted portion 408 may range from 5 mm, 10 mm, 20 mm,
30 mm, 40 mm, 45 mm, 50 mm, 60 mm, and 75 mm. FIGS. 6A-F illustrate
a perspective view, a top view, a bottom view, a front view, a back
view, and a side view, respectively, of an embodiment of a wound
dressing 400. In some embodiments, the dressing may measure 200
mm.times.150 mm. The wound dressing 400 of FIGS. 6A-F can have a
similar configuration and components as described above for FIGS.
5A-F, except the embodiments of FIG. 6A-F are of a smaller size.
Additionally, in contrast to the embodiment of FIGS. 5A-F which
comprises a 5.times.2 configuration of an array of dots viewing
windows, the embodiment of FIGS. 6A-F comprises a viewing window
configuration comprising a 3.times.2 array of dots.
[0141] FIGS. 7A-F illustrate a perspective view, a top view, a
bottom view, a front view, a back view, and a side view,
respectively, of an embodiment of a wound dressing 400. In some
embodiments, the dressing may measure 400 mm.times.100 mm. The
wound dressing 400 of FIGS. 7A-F can have a similar configuration
and components as described above for FIGS. 5A-F, except the
embodiments of FIG. 7A-F are of a different size. Additionally, in
contrast to the embodiment of FIGS. 5A-F, the embodiment of FIGS.
7A-F comprises a viewing window configuration comprising an
8.times.1 array of dots.
[0142] FIGS. 8A-F illustrate a perspective view, a top view, a
bottom view, a front view, a back view, and a side view,
respectively, of an embodiment of a wound dressing 400. In some
embodiments, the dressing may measure 300 mm.times.100 mm. The
wound dressing 400 of FIGS. 8A-F can have a similar configuration
and components as described above for FIGS. 5A-F, except the
embodiments of FIG. 8A-F are of a different size. Additionally, in
contrast to the embodiment of FIGS. 5A-F, the embodiment of FIGS.
8A-F comprises a viewing window configuration comprising a
5.times.1 array of dots.
[0143] FIGS. 9A-F illustrate a perspective view, a top view, a
bottom view, a front view, a back view, and a side view,
respectively, of an embodiment of a wound dressing 400. In some
embodiments, the dressing may measure 200 mm.times.100 mm. The
wound dressing 400 of FIGS. 9A-F can have a similar configuration
and components as described above for FIGS. 5A-F, except the
embodiments of FIG. 9A-F are of a different size. Additionally, in
contrast to the embodiment of FIGS. 5A-F, the embodiment of FIGS.
9A-F comprises a viewing window configuration comprising a
3.times.1 array of dots.
[0144] FIGS. 12A-F illustrate a perspective view, a top view, a
bottom view, a front view, a back view, and a side view,
respectively, of an embodiment of a wound dressing 400. In some
embodiments, the dressing may measure 150 mm.times.150 mm. The
wound dressing 400 of FIGS. 12A-F can have a similar configuration
and components as described above for FIGS. 5A-F, except the
embodiments of FIG. 9A-F are of a different size. Additionally, in
contrast to the embodiment of FIGS. 5A-F, the embodiment of FIGS.
12A-F comprises a viewing window configuration comprising a
quincunx array of dots. The quincunx array of dots configuration
consists of five dots arranged in a cross, with four of the dots
forming a square or rectangle where one dot is positioned at each
of the four corners of the square or rectangle shaped wound
dressing and a fifth dot in the center. However, one corner of the
wound dressing preferably has the fluidic connector or port 406 in
place of a dot in the quincunx dot array.
[0145] FIGS. 10A-F illustrate a perspective view, a top view, a
bottom view, a front view, a back view, and a side view,
respectively, of an embodiment of a wound dressing 400. In some
embodiments, the dressing may measure 250 mm.times.250 mm. The
wound dressing 400 of FIGS. 10A-F can have a similar configuration
and components as described above for FIGS. 5A-F, except the
embodiments of FIG. 10A-F are of a different size. Additionally, in
contrast to the embodiment of FIGS. 5A-F, the embodiment of FIGS.
10A-F comprises a viewing window configuration comprising a
3.times.3 array of dots with an absent dot at a corner position of
the wound dressing and in its place is a domed port or a fluidic
connector 406 completing the 3.times.3 array.
[0146] FIGS. 11A-F illustrate a perspective view, a top view, a
bottom view, a front view, a back view, and a side view,
respectively, of an embodiment of a wound dressing 400. In some
embodiments, the dressing may measure 200 mm.times.200 mm. The
wound dressing 400 of FIGS. 11A-F can have a similar configuration
and components as described above for FIGS. 5A-F, except the
embodiments of FIG. 11A-F are of a different size. Additionally, in
contrast to the embodiment of FIGS. 5A-F, the embodiment of FIGS.
11A-F comprises a viewing window configuration comprising a
3.times.3 array of dots with an absent dot at a corner position of
the wound dressing and in its place is a domed port or a fluidic
connector completing the 3.times.3 array.
[0147] The additional sizes and shapes illustrated in FIGS. 5A-F,
6A-F, 7A-F, 8A-F, 9A-F, 10A-F, 11A-F, 12A-F, and 24 may incorporate
the waisted portion 408, obscuring layer 404, viewing windows 403,
and other components and embodiments described herein.
[0148] FIGS. 13A, 13B, and 14 illustrate embodiments of a dressing
500 comprising one or more orifice viewing windows 502 at, near, or
adjacent to the port. The orifice viewing windows 502 can be
provided at, near, adjacent to the port 504 in the backing layer
for viewing of the absorbent material 503 present in proximity to
the port 504. The orifice viewing windows 502 can have the same
structure and/or function as the viewing windows herein described.
In some embodiments, the orifice viewing window 502 can be formed
from a cross-shaped or Maltese-cross-shaped aperture or cut-out 501
in the obscuring layer. The arms of the cross-shaped cut-out 501
can be aligned with the longitudinal length and transverse width of
the absorbent material 503 as shown in FIG. 13A. Alternatively, the
arms of the cross-shaped cut-out 501 can be offset from the
longitudinal length and transverse width of the absorbent material,
at an angle, for example, a 45.degree. angle, as illustrated in
FIG. 13B. The arms of the cross-shaped cut-out may span a larger
dimension than a hole in the absorbent material below the cut-out
501. For example, the arms may span a dimension of about 25 mm,
while the through-hole in the absorbent material may have a
diameter of 10 mm.
[0149] Additionally, FIG. 14 illustrates an embodiment of a wound
dressing 600 in which the arms of the cross-shaped aperture can
have flared edges 601. The orifice viewing windows 502 at, near, or
adjacent to the port 604 may be used to indicate that fluid is
approaching the port 604 or that the dressing 600 is otherwise
becoming saturated. This can assist the clinician or patient in
maintaining the wound dressing and determining when to change the
dressing, because once fluid contacts the center of the port, such
fluid contact may at least partially occlude the hydrophobic filter
that may be contained therein so as to interrupt or at least
partially block the application of negative pressure. The orifice
viewing windows 502 can be used with the fluidic connector as well
as the domed port or any other suitable connector.
[0150] As with FIGS. 15A and 15B, the wound dressing may also be
provided with one or more slits 2150 to aid the dressing in
conforming to a non-planar area. FIG. 15A illustrates an embodiment
of a wound dressing 2100 with a narrowed central portion or waisted
portion 2120 and concentric slits 2150. This embodiment may be
useful for the treatment of wounds on non-planar surfaces or
otherwise contoured wounds, including, for example, feet, knees,
sacral regions, or other such areas. In some embodiments, the wound
dressing 2100 may provide for one or more slits 2150 cut into the
dressing, preferably into the absorbent layer, that may enhance the
conformability of the dressing. In this embodiment, the slits 2150
are cut in concentric ovoid arcs, although other configurations (as
discussed below) are possible. Preferably, the area under the port
2130 or fluidic connector disposed at the top of the device is free
from the slits 2150, as this may interfere with fluid transfer from
the dressing. In some embodiments, the slits 2150 may be formed as
part of, in addition to, or instead of baffles that may be present
within the absorbent layer so as to may aid in distribution of
wound exudate. In these embodiments, and with all other embodiments
described herein, although a domed connector is shown attached to
the dressing, this may be interchanged with any other suitable
connector, including for example embodiments of the fluidic
connectors described in FIGS. 23A and 23B (as described below).
[0151] FIG. 15B illustrates an embodiment of a wound dressing 2100
with a narrow central portion 2120. Here, however, one or more
slits 2150 extending across the width of the dressing may be
present. Preferably, these slits 2150 do not extend entirely across
the width of the dressing, in order to promote fluid transfer
within the absorbent layer. The slits 2150 may enhance
conformability of the dressing, possibly in conjunction with the
waisted configuration of the dressing, when applied to a non-planar
or contoured wound area. For example, such a dressing 2100 may be
useful when applied so as to wrap around an arm or a leg.
[0152] FIGS. 23A and 23B illustrate embodiments of white and black
fluidic connectors 2410, 2420, respectively, that may be used to
connect an embodiment of a wound dressing described herein to a
source of negative pressure. In some embodiments, the domed port
used in other embodiments discussed herein (e.g., as illustrated
above in FIG. 1) may be replaced by the fluidic connector 2410,
2420, for example as illustrated in FIGS. 16-19. The fluidic
connector 2410, 2420 may be flexible and/or enhance the comfort of
the patient. The fluidic connector 2410, 2420 preferably comprises
a fluidic connector body configured to transmit fluid through
itself, including, for example, negative pressure and/or wound
exudate. The fluidic connector body is preferably encapsulated
within one or more layers of fluid-impermeable material. In some
embodiments, the fluid-impermeable material is heat-sealed together
to enclose the fluid connector body.
[0153] With reference now to FIG. 23A, the body of the fluidic
connector 2410 is preferably be constructed from a material
configured to transmit fluids therethrough, including fabrics such
as 3D fabric. In some embodiments, the thickness of the fluidic
connector body may measure between 0.5 to 4 mm, preferably 0.7 to 3
mm, and even more preferably between 1 and 2 mm; in a preferred
embodiment the fluid connector body is 1.5 mm thick. Suitable
materials that may be used for the fluidic connector body,
including the 3D fabric, are disclosed in U.S. application Ser. No.
13/381,885, filed Dec. 30, 2011, published as US2012/0116334,
titled "APPARATUSES AND METHODS FOR NEGATIVE PRESSURE WOUND
THERAPY," and which is hereby incorporated by reference in its
entirety. Use of the 3D fabric in the fluidic connector body may
help alleviate fluid blockage when the connector is kinked, and may
further provide for a soft fluidic connector that alleviates
contact pressure onto a patient, for example when the patient's
weight is pressed against the fluidic connector. This may enhance
patient comfort and reduce the likelihood of pressure ulcers.
[0154] Testing of various weights in various configurations on
embodiments of fluidic connectors comprising a 3D fabric was
completed. The testing included weights above those believed to be
likely to be encountered by a patient, as maximal pressure on a
heel for a patient using dressings was found to be 1.3 kg/cm.sup.2
in some studies. Preferably, embodiments of the fluidic connectors
described herein, especially when comprising 3D fabric, can
transmit therapeutic levels of negative pressure (i.e., in an
amount sufficient to heal a wound) while a weight is pressed down
thereupon. For example, embodiments are preferably able to transmit
therapeutic levels of negative pressure while an external pressure
applied on the dressing and/or 3D fabric of up to 1 kg/cm.sup.2,
preferably up to 2 kg/cm.sup.2, and even more preferably up to 4
kg/cm.sup.2. Certain embodiments, as described below, have been
tested as being capable of transmitting therapeutic levels of
negative pressure while an external pressure applied on the
dressing and/or 3D fabric is above 6 kg/cm.sup.2.
[0155] In the testing, a 400 ml wound cavity was used, and pressure
was measured both at the wound and at the pump. Embodiments of a
fluidic connector comprising 3D fabric were tested when laid flat
with a weight placed thereupon. Testing indicated that when no
pressure was applied to the fluidic connector, the pressure
differential between the pressure at the pump and at the cavity was
approximately 2 mmHg. Various different weights were applied,
ranging between 2 and 12 kg/cm.sup.2, in 2 kg increments, and the
resulting pressure difference was approximately linear, with the
pressure difference at 12 kg/cm.sup.2 being calculated at 33 mmHg,
while the pressure difference at 2 kg/cm.sup.2 being only 16 mmHg.
The relation between the pressure difference in mmHg was found to
equal approximately 4.5 times the applied load in kg/cm.sup.2.
Testing also indicated that the relative pressure difference
between the pressure at the pump and the pressure at the wound
after five minutes was less than 10 mmHg when measured at the pump
for loads under 4 kg/cm.sup.2, and under 20 mmHg when measured at
the wound for loads under 4 kg/cm.sup.2.
[0156] Testing was also performed with a weight laid on an
embodiment of a fluidic connector, while being bent at a 90.degree.
angle. Various different weights were applied, ranging between 2
and 12 kg/cm.sup.2, in 2 kg increments, and the resulting pressure
difference was approximately linear, with the pressure difference
at 12 kg/cm.sup.2 being calculated at 51 mmHg, while the pressure
difference at 2 kg/cm.sup.2 being 17 mmHg. The relation between the
pressure difference in mmHg was found to equal approximately 8
times the applied load in kg/cm.sup.2. Testing also indicated that
the relative pressure difference between the pressure at the pump
and the pressure at the wound after five minutes was approximately
20 mmHg when measured at the pump for loads under 4 kg/cm.sup.2,
and under 30 mmHg when measured at the wound for loads under 4
kg/cm.sup.2.
[0157] Further testing was performed with a weight laid on an
embodiment of a fluidic connector, while being bent at a
180.degree. angle (i.e., folded over itself). Various different
weights were applied, ranging between 2 and 12 kg/cm.sup.2, in 2 kg
increments, and the resulting pressure difference was approximately
linear, with the pressure difference at 12 kg/cm.sup.2 being
calculated at 76 mmHg, while the pressure difference at 2
kg/cm.sup.2 being 25 mmHg. The relation between the pressure
difference in mmHg was found to equal approximately 10.7 times the
applied load in kg/cm.sup.2. Testing also indicated that the
relative pressure difference between the pressure at the pump and
the pressure at the wound after five minutes was approximately 20
mmHg when measured at the pump for loads under 4 kg/cm.sup.2, and
under 30 mmHg when measured at the wound for loads under 4
kg/cm.sup.2.
[0158] Testing was also performed on different widths and
thicknesses of 3D fabric that may be used in embodiments of fluidic
connectors described herein. In a particular example, the maximum
negative pressure that could be applied using 3D fabric measuring
1, 1.25, 1.5, 1.75, and 2 cm in width was found to be between 85
and 92 mmHg, respectively. Upon application of an applied load of 1
kg/cm.sup.2, however, the maximum negative pressure applied for a 1
cm-width embodiment dropped to 75 mmHg, while the 1.25 and 1.5
cm-width embodiments were essentially unchanged, exhibiting
pressures between 85 and 90 mmHg. Application of a 1 kg/cm.sup.2
weight made the 1 cm-width embodiment maximum negative pressure
drop to about 73 mmHg, while the 1.25 cm-width embodiment dropped
to about 84 mmHg. The 1.5 cm-width embodiment showed a minimal
maximum negative pressure change down to approximately 86 mmHg. As
tested, the greatest increases in flow rate (as evidenced by the
maximal negative pressures applied) were greatest when increasing
the width of the 3D fabric from 1 cm to 1.25 cm, and stabilized
above 1.5 cm. Similarly, increasing the width of the 3D fabric
(i.e., above 1 cm) was found to slightly reduce the amount of time
required to pump a wound cavity down to a target negative
pressure.
[0159] Further testing with single and double layers of Baltex 3540
3D fabric, either single or double thickness, indicated that while
the maximum negative pressure applied using a single thickness
fabric dropped from about 88 mmHg with no applied weight to about
73 mmHg with a 2 kg/cm.sup.2 weight. However, a double thickness
fabric showed minimal change in the maximum amount of negative
pressure applied, dropping from 90 mmHg with no weight applied to
about 87 mmHg with an applied load of 2 kg/cm.sup.2.
[0160] Depending on the particular application, using wider and/or
thicker 3D fabric may permit improved air flow, together with
greater pressure and kink resistance in some context; this may be
useful especially if higher absolute negative pressure need to be
applied to the wound. However, the greater kink and pressure
resistance may need to be balanced with other concerns such as
perceived bulk and size of the fluidic connector, aesthetics, and
comfort, which may require use of a thinner 3D fabric.
[0161] In some embodiments, the proximal end 2411 of the fluidic
connector 2410 is configured to be connected to a tube or other
conduit that is in fluid communication with a source of negative
pressure via the fluid connector body, although some embodiments
may provide for the fluidic connector 2410 to be directly
connectable to a source of negative pressure without needing a
conventional tube. The distal end 2412 of the fluidic connector
2410 may be enlarged, and is configured to be attached and/or
adhered to a dressing, for example via an aperture in the backing
layer of the dressing and/or in the fluidic connector 2410, so that
the fluid connector body is in fluid communication therewith.
[0162] In one configuration and as illustrated in FIG. 23A, the
distal end 2412 of the fluidic connector 2410 may be convex on one
side and flat on the opposite side. As illustrated in FIGS. 16-18
below, the flat side may be aligned with the edge of the absorbent
layer with the convex side extending over the aperture in the
backing layer. The fluidic connector 2410 may be provided
preattached to the dressing portion, or may be provided in an
unattached format so as to be connectable to the dressing portion
by the patient or caregiver. The enlarged distal end 2412 may aid
in providing a larger area capable of transmitting negative
pressure to the dressing, although the distal end may be provided
without any enlargement. Although preferred embodiments of the
fluidic connector 2410 are used in dressings that contain
substantially all wound exudate within the absorbent material, such
that the fluidic connector transmits essentially only air, some
embodiments of the fluidic connector may be configured so as to
transfer exudate in addition to air. In embodiments of the fluidic
connector that are configured to transfer essentially only air
(while wound exudate remains substantially within the absorbent
material), the distal end of the fluidic connector is preferably
provided with a filter configured to block fluid transport beyond
itself, such as a hydrophobic filter. An example of such a
configuration is described in U.S. Provisional Application Ser. No.
61/650,904, filed May 23, 2012, titled "APPARATUSES AND METHODS FOR
NEGATIVE PRESSURE WOUND THERAPY," and which is hereby incorporated
into this present application in its entirety.
[0163] In embodiments of the fluidic connector that are configured
to transfer exudate in addition to air, the fluidic connector may
be provided with a secondary air leak channel configured to provide
a flow of ambient air to the wound site. Preferably, the secondary
air leak channel is provided with a filter to prevent contamination
of the wound.
[0164] Turning now to FIG. 23B, this figure shows an embodiment
similar to FIG. 23A, but where the fluidic connector 2420 may
appear colored, for example as a result of an obscuring layer
similar to that previously described. In some embodiments,
obscuring coloration may be provided by dyeing the material used in
the fluidic connector 2420, for example the 3D fabric that may be
used therein. In some embodiments, the obscuring layer may be
placed above the 3D fabric, either above or below the
fluid-impermeable material. In some embodiments, the encapsulating
fluid-impermeable material may be colored or tinted. Coloring the
fluidic connector 2420 (e.g, via the obscuring layer) may enhance
the aesthetic appeal of the device, help in disguising or making
the device less obtrusive (in particular when the fluidic connector
is visible to others), and, when the fluidic connector is used to
transfer exudates away from the wound, may hide the presence of the
exudates therein.
[0165] In some embodiments, the fluidic connector body may be
colored as a result of an auxiliary compound such as activated
charcoal. Further, some embodiments may provide for text or images
to be printed thereon, for example for instructional or advertising
purposes. Such improvements may enhance patient comfort and
minimize embarrassment, thereby increasing patient compliance and
satisfaction with the device. The obscuring layer in the fluidic
connector can have all features described with reference to the
obscuring layer of the wound dressing as herein described.
[0166] FIG. 17 illustrates an embodiment of a wound dressing 720
that comprises a hexagonal backing layer and a three-lobed
configuration for the absorbent material and the obscuring layer.
This wound dressing 720, as with several other embodiments
described herein, may be advantageously applied to wounds or areas
surrounding wounds that are located in non-planar areas. The
embodiment illustrated here may be particularly advantageous when
applied to protruding body portions, for example elbows and
heels.
[0167] FIG. 18 illustrates a wound dressing 730 with a three-lobed
configuration similar in some respects to the embodiment
illustrated in FIG. 17. Here, however, the dressing is smaller and
comprises more rounded projections. FIGS. 16-18 illustrate a
fluidic connector 721, 731 similar to those described in FIGS. 23A
and 23B attached to the device, with the flat end aligned with the
edge of the absorbent material and the convex end extending over an
aperture in the backing layer. This fluidic connector may enhance
comfort and prevent pressure ulcers or other complications that may
result from extended pressure of a conventional tube onto the wound
or skin surrounding the wound (as described above). Of course,
different connectors may be used, such as the domed port
illustrated in FIG. 1.
[0168] FIGS. 19-20 also illustrate additional embodiments of wound
dressings 740, 750 with three-lobed configurations for the
absorbent material and a hexagonal backing layer. The wound
dressing 750 illustrated in FIG. 20 is larger where the lobes of
the absorbent material comprises flared ends, while the wound
dressing 740 illustrated in FIG. 19 is smaller and the absorbent
material does not have flared ends. All suitable fluidic connectors
or conduits may be used, and the domed port connector of FIG. 20
may be used in place of the fluidic connector of FIG. 19, and vice
versa. As with the preceding embodiments, the absorbent layers may
be colored or obscured, and one or more slits may be formed onto
the absorbent layers to enhance conformability to non-planar
surfaces. It will be appreciated that in the embodiments of FIGS.
17-20, the number of lobes may be varied, and the backing layer can
have other shapes, and is not limited to being hexagonal.
[0169] Additionally, FIGS. 21A-C and 22 illustrate embodiments of a
wound dressing 760, 770, 780, 790 that comprises a four-lobed
configuration. Although these embodiments are illustrated without a
port or fluidic connector attached thereto, it will of course be
understood that such ports and fluidic connectors are envisioned
and may be attached in a similar fashion as described previously
herein. FIGS. 21A-C comprise embodiments of a four-lobed wound
dressing comprising an obscuring layer and viewing windows
extending through the obscuring layer. The viewing windows can be
used as discussed above for visualization of wound exudate in the
absorbent layer. Examples of such viewing windows are illustrated
in FIGS. 21A and 21B. The dressing 760 shown in FIG. 21A includes
an obscuring layer 762 and crescent-shaped viewing windows 764
provided in the obscuring layer to extend through the obscuring
layer allowing visibility of the dressing therebelow. The dressing
770 of FIG. 21B includes an obscuring layer 772 and a number of
holes 774 therethrough acting as viewing windows for viewing the
state of the dressing therebelow. FIG. 21C shows another dressing
780 including an obscuring layer 782 with viewing windows 784. With
the dressings 760, 770, 780 the progress of exudate spread over the
dressing and towards the edge of the dressing can be monitored.
[0170] FIG. 22 illustrates a perspective view of an embodiment of a
wound dressing 790 according to an embodiment of the four-lobe
configuration. FIG. 22 shows a possible four-lobe configuration of
a dressing, useful for enhanced compatibility with body movement,
where each layer is shaped to reduce the incident angle of the pad
edge, and to provide somewhat independently moving sub-sections of
the dressing. The dressing border, including the wound contact
layer 791 and the backing layer 792 can also comprise slits,
provided to further enhance the conformability on application by
allowing the borders to overlap if needed. The wound dressing with
a four-lobe configuration, as well as other configurations, are
described in detail in International Application PCT/GB2012/000587,
titled "WOUND DRESSING AND METHOD OF TREATMENT" and filed on Jul.
12, 2012. which is incorporated by reference herein.
[0171] Additionally, FIGS. 24A-F illustrate an embodiment of a
wound dressing 2300 with an oval shaped absorbent layer 2308 having
multiple lobes 2301. FIGS. 24A-F illustrate, respectively,
perspective, top, bottom, left, right, and side views of an
embodiment of the dressing 2300. In some embodiments, the absorbent
layer 2308 can have six lobes. Preferably, two or more lobes 2301
(e.g., six lobes) are provided on the wound dressing 2300; the
lobes 2301, and specifically, the gaps between the lobes 2301, aid
the wound dressing 2300 in conforming to nonplanar wounds. For
example, it may be advantageous to use the dressing 2300 to conform
around joints such as elbows and knees.
[0172] The dressing 2300 can have a rectangular or square shaped
backing layer 2302, and in some embodiments, the overall dressing
2300 may measure 190 mm.times.230 mm, or 145.5 mm.times.190 mm.
Preferably, a fluidic connector such as a port 2306 is attached to
the dressing 2300, although it will of be recognized that the
fluidic connector of FIGS. 23A-B may be used instead or in
addition. Additionally, in some embodiments, the dressing 2300 can
have an obscuring layer 2304 and one or more viewing windows 2303
similar to that described for other embodiments herein. FIG. 24A
illustrates a perspective view of the dressing 2300, while FIG. 24B
illustrates a top view, 24C a bottom view, and 24D-F represent
views of the four sides of the dressing 2300.
[0173] FIG. 25 illustrates an embodiment similar in shape and
overall configuration to the embodiments illustrated above in FIGS.
7A-F. Here, however, the dressing 500 comprises an orifice viewing
window 502 similar to that described in relation to FIGS. 13A-B and
14. The orifice viewing window 502 is preferably formed from a
cross-shaped or Maltese-cross shaped aperture or cutout 501 in the
obscuring layer 506. The backing layer 510 provided over the
obscuring layer preferably has an orifice 504 located at the center
of the orifice viewing window 502. Reference number 504 can also be
considered to designate a port that may be provided in or over the
backing layer 510 to provide a connection to a source of negative
pressure, for example, a port provided over the orifice in the
backing layer as described above. A smaller orifice 505 may be
located in the absorbent layer 503 that is provided below the
obscuring layer 506. The dressing 500 may comprise one or more
viewing windows 507; here, eight viewing windows 507 are provided
in a linear arrangement. The bottom side of the dressing 500
optionally comprises a layer of adhesive, over which a release
layer 513 may be placed. Lines 512 illustrate possible locations
where breaks in the release liner 513 may be provided.
[0174] In a preferred embodiment, the dressing 500 illustrated here
has a longitudinal length of approximately 400 mm, and a transverse
width of approximately 100 mm. The central axis of each arm of the
cutout 501 of the orifice viewing window 502 is preferably offset
from the longitudinal length and transverse width of the absorbent
material, at an angle, for example, a 45.degree. angle, as
illustrated. The spacing between each arm of the cutout 501 may be,
as illustrated here, 72.degree., although it will of course be
recognized that other angles and configurations are possible. Lines
512, indicating possible locations where breaks in the release
liner 513 may be provided, can be located, for example, at 80 mm,
40.+-.4 mm, and 25.+-.4 mm from each of the top and bottom edges of
the dressing 500. As illustrated, the orifice or port 504 (and
cutout 501) are preferably centered on the transverse midline of
the dressing 500, and situated approximately 52-55 mm from the top
edge of the dressing 500. Although the location may be changed, it
may be preferable to locate the port 504 near or along a side,
edge, or corner of the dressing 500, which is then preferably
elevated with respect to the remainder of the dressing. This
configuration may extend the life of the dressing, as fluid would
be slower in saturating the absorbent layer below or near the
orifice or port 504.
[0175] FIG. 26 illustrates an embodiment similar in shape and
overall configuration to the embodiments illustrated above in FIGS.
8A-F. Here, however, the dressing 500 comprises an orifice viewing
window 502 and cutout 501, with for example five linearly arranged
viewing windows 507, among other parts, that are similar to that
described above in relation to FIG. 25. In a preferred embodiment,
the dressing 500 illustrated here has a longitudinal length of
approximately 300 mm, and a transverse width of approximately 100
mm. The spacing between each arm of the cutout 501 may be, as
illustrated here, 72.degree., although it will of course be
recognized that other angles and configurations are possible. Lines
512, indicating possible locations where breaks in the release
liner 513 may be provided, can be located, for example, at 80 mm,
40.+-.4 mm, and 25.+-.4 mm from each of the top and bottom edges of
the dressing 500. As illustrated, the orifice or port 504 (and
cutout 501) are preferably centered on the transverse midline of
the dressing 500, and situated approximately 52-55 mm from the top
edge of the dressing 500.
[0176] FIG. 27 illustrates an embodiment similar in shape and
overall configuration to the embodiments illustrated above in FIGS.
9A-F. Here, however, the dressing 500 comprises an orifice viewing
window 502 and cutout 501, with for example three linearly arranged
viewing windows 507, among other parts, that are similar to that
described above in relation to FIG. 25. In a preferred embodiment,
the dressing 500 illustrated here has a longitudinal length of
approximately 200 mm, and a transverse width of approximately 100
mm. The spacing between each arm of the cutout 501 may be, as
illustrated here, 72.degree., although it will of course be
recognized that other angles and configurations are possible. Lines
512, indicating possible locations where breaks in the release
liner 513 may be provided, can be located, for example, at 80 mm,
40.+-.4 mm, and 25.+-.4 mm from each of the top and bottom edges of
the dressing 500. As illustrated, the orifice or port 504 (and
cutout 501) are preferably centered on the transverse midline of
the dressing 500, and situated approximately 52-55 mm from the top
edge of the dressing 500.
[0177] FIG. 28 illustrates an embodiment similar in shape and
overall configuration to the embodiments illustrated above in FIGS.
5A-F. Here, however, the dressing 500 comprises an orifice viewing
window 502 and cutout 501, with for example two rows of five
linearly arranged viewing windows 507, among other parts, that are
similar to that described above in relation to FIG. 25. In a
preferred embodiment, the dressing 500 illustrated here has a
longitudinal length of approximately 300 mm, and a transverse width
of approximately 150 mm. The spacing between each arm of the cutout
501 may be, as illustrated here, 72.degree., although it will of
course be recognized that other angles and configurations are
possible. Lines 512, indicating possible locations where breaks in
the release liner 513 may be provided, can be located, for example,
at 80 mm, 40.+-.4 mm, and 25.+-.4 mm from each of the top and
bottom edges of the dressing 500. As illustrated, the orifice or
port 504 (and cutout 501) are preferably centered on the transverse
midline of the dressing 500, and situated approximately 52-55 mm
from the top edge of the dressing 500.
[0178] FIG. 29 illustrates an embodiment similar in shape and
overall configuration to the embodiments illustrated above in FIGS.
6A-F. Here, however, the dressing 500 comprises an orifice viewing
window 502 and cutout 501, with for example two rows of three
linearly arranged viewing windows 507, among other parts, that are
similar to that described above in relation to FIG. 25. In a
preferred embodiment, the dressing 500 illustrated here has a
longitudinal length of approximately 300 mm, and a transverse width
of approximately 100 mm. The spacing between each arm of the cutout
501 may be, as illustrated here, 72.degree., although it will of
course be recognized that other angles and configurations are
possible. Lines 512, indicating possible locations where breaks in
the release liner 513 may be provided, can be located, for example,
at 80 mm, 40.+-.4 mm, and 25.+-.4 mm from each of the top and
bottom edges of the dressing 500. As illustrated, the orifice or
port 504 (and cutout 501) are preferably centered on the transverse
midline of the dressing 500, and situated approximately 52-55 mm
from the top edge of the dressing 500.
[0179] FIG. 30 illustrates an embodiment similar in shape and
overall configuration to the embodiments illustrated above in FIGS.
10A-F. Here, however, the dressing 500 comprises an orifice viewing
window 502 and cutout 501, with a 3.times.3 array of viewing
windows absent a viewing window at a corner position of the wound
dressing, among other parts, that are similar to that described
above in relation to FIG. 25 but located in a corner of the
dressing 500. In a preferred embodiment, the dressing 500
illustrated here is approximately square, with each side measuring
approximately 250 mm. The spacing between each arm of the cutout
501 may be, as illustrated here, 72.degree., although it will of
course be recognized that other angles and configurations are
possible. Lines 512, indicating possible locations where breaks in
the release liner 513 may be provided, can be located, for example,
at 80 mm, 40.+-.4 mm, and 25.+-.4 mm from each of the top and
bottom edges of the dressing 500. As illustrated, the orifice or
port 504 (and cutout 501) are preferably centered on a corner of
the dressing 500, and situated approximately 52-55 mm from the top
edge of the dressing 500.
[0180] FIG. 31 illustrates an embodiment similar in shape and
overall configuration to the embodiments illustrated above in FIGS.
11A-F. Here, however, the dressing 500 comprises an orifice viewing
window 502 and cutout 501, with a 3.times.3 array of viewing
windows absent a viewing window at a corner position of the wound
dressing, among other parts, that are similar to that described
above in relation to FIG. 25 but located in a corner of the
dressing 500. In a preferred embodiment, the dressing 500
illustrated here is approximately square, with each side measuring
approximately 200 mm. The spacing between each arm of the cutout
501 may be, as illustrated here, 72.degree., although it will of
course be recognized that other angles and configurations are
possible. Lines 512, indicating possible locations where breaks in
the release liner 513 may be provided, can be located, for example,
at 80 mm, 40.+-.4 mm, and 25.+-.4 mm from each of the top and
bottom edges of the dressing 500. As illustrated, the orifice or
port 504 (and cutout 501) are preferably centered on a corner of
the dressing 500, and situated approximately 52-55 mm from the top
edge of the dressing 500.
[0181] FIG. 32 illustrates an embodiment similar in shape and
overall configuration to the embodiments illustrated above in FIGS.
12A-F. Here, however, the dressing 500 comprises an orifice viewing
window 502 and cutout 501, with a quincunx array of viewing windows
absent a viewing window at a corner position of the wound dressing,
among other parts, that are similar to that described above in
relation to FIG. 25 but located in a corner of the dressing 500. In
a preferred embodiment, the dressing 500 illustrated here is
approximately square, with each side measuring approximately 150
mm. The spacing between each arm of the cutout 501 may be, as
illustrated here, 72.degree., although it will of course be
recognized that other angles and configurations are possible. Lines
512, indicating possible locations where breaks in the release
liner 513 may be provided, can be located, for example, at 80 mm,
40.+-.4 mm, and 25.+-.4 mm from each of the top and bottom edges of
the dressing 500. As illustrated, the port 504 (and cutout 501) are
preferably centered on a corner of the dressing 500, and situated
approximately 52-55 mm from the top edge of the dressing 500.
[0182] FIG. 33A-B illustrates an embodiment somewhat similar in
shape and overall configuration to the embodiments illustrated
above in FIGS. 24A-F. Here, however, the oval-shaped dressing 500
comprises an orifice viewing window 502 and cutout 501, among other
parts, that are similar to that described above in relation to FIG.
25. Viewing windows are not shown, but may be provided as in one
embodiment as described above. In a preferred embodiment, the
dressing 500 illustrated in FIG. 33A has a longitudinal length of
approximately 250 mm, and a transverse width of approximately 200
mm. The longitudinal length of the absorbent layer 503 (and
corresponding obscuring layer, if so provided) measures
approximately 200 mm, with a transverse width of approximately 150
mm. The embodiment of the dressing 500 illustrated in FIG. 33B has
a longitudinal length of approximately 200 mm, and a transverse
width of approximately 150 mm. The longitudinal length of the
absorbent layer 503 (and corresponding obscuring layer, if so
provided) measures approximately 150 mm, with a transverse width of
approximately 100 mm. Although no viewing windows 507 are
illustrated, it will of course be understood that one or more such
windows 507 may be provided on the dressing 500. The spacing
between each arm of the cutout 501 may be 72.degree., although it
will of course be recognized that other angles and configurations
are possible. As illustrated, the orifice or port 504 (and cutout
501) are preferably centered on the transverse midline of the
dressing 500, and situated approximately 52-55 mm from the top edge
of the dressing 500.
[0183] FIG. 34A illustrates an exploded view of a dressing 3400 for
use in negative pressure wound therapy. Although this figure
illustrates a dressing having one particular shape, the
construction of the layers can be applied to any of the embodiments
identified above, including FIGS. 4A-14, 16-22, and 24A-33B. The
dressing 3400 comprises a release layer 3480, wound contact layer
3460, a transmission layer 3450, an acquisition distribution layer
3440, an absorbent layer 3430, an obscuring layer 3420, and a
backing layer 3410. The dressing 3400 may be connected to a port,
such as described below with respect to FIGS. 35 and 36. At least
the wound contact layer 3460, transmission layer 3450, absorbent
layer 3430, obscuring layer 3420, and backing layer 3410 may have
properties as described with respect to particular embodiments
above, such as the embodiments of FIGS. 3A-22, and 24A-33B, as well
as or instead of the properties described below.
[0184] The dressing 3400 may comprise a wound contact layer 3460
for sealing the dressing 3400 to the healthy skin of a patient
surrounding a wound area. Certain embodiments of the wound contact
layer may comprise three layers: a polyurethane film layer, a lower
adhesive layer and an upper adhesive layer. The upper adhesive
layer may assist in maintaining the integrity of the dressing 3400,
and the lower adhesive layer may be employed for sealing the
dressing 3400 to the healthy skin of a patient around a wound site.
As described above, in some embodiments with respect to FIGS. 3A-C,
some embodiments of the polyurethane film layer may be perforated.
Some embodiments of the polyurethane film layer and upper and lower
adhesive layers may be perforated together after the adhesive
layers have been applied to the polyurethane film. In some
embodiments a pressure sensitive adhesive, which may be a silicone,
hot melt, hydrocolloid or acrylic based adhesive or other such
adhesives, may be formed on both sides or optionally on a selected
one side of the wound contact layer. In certain embodiments, the
upper adhesive layer may comprise an acrylic pressure sensitive
adhesive, and the lower adhesive layer may comprise a silicone
pressure sensitive adhesive. In other embodiments the wound contact
layer 3460 may not be provided with adhesive. In some embodiments,
the wound contact layer 3460 may be transparent or translucent. The
film layer of the wound contact layer 3460 may define a perimeter
with a rectangular or a square shape. A release layer 3480 may be
removably attached to the underside of the wound contact layer
3460, for example covering the lower adhesive layer, and may be
peeled off using flaps 3481. Some embodiments of the release layer
3480 may have a plurality of flaps extending along the length of
the layer 3480.
[0185] Some embodiments of the dressing 3400 may comprise an
optional spacer or transmission layer 3450. The transmission layer
3450 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 can ensure that an open air channel can
be maintained to communicate negative pressure over the wound area
even when the absorbent layer 3430 has absorbed substantial amounts
of exudates. 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.
[0186] Some embodiments of the transmission layer 3450 may be
formed of a material having a three dimensional structure. For
example, a knitted or woven spacer fabric (for example Baltex 7970
weft knitted polyester) or a non-woven fabric can be used. In some
embodiments, the transmission layer 3450 can have a 3D polyester
spacer fabric layer. This layer can have a top layer which is a
84/144 textured polyester, and a bottom layer which can be a 100
denier flat polyester and a third layer formed sandwiched between
these two layers which is a region defined by a knitted polyester
viscose, cellulose or the like monofilament fiber. In use, this
differential between filament counts in the spaced apart layers
tends to draw liquid away from the wound bed and into a central
region of the dressing 3400 where the absorbent layer 3430 helps
lock the liquid away or itself wicks the liquid onwards towards the
cover layer 3410 where it can be transpired. Other materials can be
utilized, and examples of such materials are described in U.S.
Patent Pub. No. 2011/0282309, which are hereby incorporated by
reference and made part of this disclosure. However, the
transmission layer 3450 may be optional, and for example may be
optional in embodiments of the dressing 3400 which comprise the
acquisition distribution layer 3440, described below.
[0187] Some embodiments may comprise a wicking or acquisition
distribution layer (ADL) 3440 to horizontally wick fluid such as
wound exudate as it is absorbed upward through the layers of the
dressing 3400. Lateral wicking of fluid may allow maximum
distribution of the fluid through the absorbent layer 3430 and may
enable the absorbent layer 3430 to reach its full holding capacity.
This may advantageously increase moisture vapor permeation and
efficient delivery of negative pressure to the wound site. Some
embodiments of the ADL 3440 may comprise viscose, polyester,
polypropylene, cellulose, or a combination of some or all of these,
and the material may be needle-punched. Some embodiments of the ADL
3440 may comprise polyethylene in the range of 40-150 grams per
square meter (gsm).
[0188] The dressing 3400 may further comprise an absorbent or
superabsorbent layer 3430. The absorbent layer can be manufactured
from ALLEVYN.TM. foam, Freudenberg 114-224-4 and/or
Chem-Posite.TM.11C-450, or any other suitable material. In some
embodiments, the absorbent layer 3430 can be a layer of non-woven
cellulose fibers having super-absorbent material in the form of dry
particles dispersed throughout. Use of the cellulose fibers
introduces fast wicking elements which help quickly and evenly
distribute liquid taken up by the dressing. The juxtaposition of
multiple strand-like fibers leads to strong capillary action in the
fibrous pad which helps distribute liquid.
[0189] For example, some embodiments of the absorbent layer 3430
may comprise a layered construction of an upper layer of non-woven
cellulose fibers, superabsorbent particles (SAP), and a lower layer
of cellulose fibers with 40-80% SAP. In some embodiments, the
absorbent layer 3430 may be an air-laid material. Heat fusible
fibers can optionally be used to assist in holding the structure of
the pad together. Some embodiments may combine cellulose fibers and
air-laid materials, and may further comprise up to 60% SAP. Some
embodiments may comprise 60% SAP and 40% cellulose. Other
embodiments of the absorbent layer may comprise between 60% and 90%
(or between about 60% and about 90%) cellulose matrix and between
10% and 40% (or between about 10% and about 40%) superabsorbent
particles. For example, the absorbent layer may have about 20%
superabsorbent material and about 80% cellulose fibers. It will be
appreciated that rather than using super-absorbing particles or in
addition to such use, super-absorbing fibers can be utilized
according to some embodiments of the present invention. An example
of a suitable material is the Product Chem-Posite.TM. 11 C
available from Emerging Technologies Inc (ETi) in the USA.
[0190] Super-absorber particles/fibers can be, for example, sodium
polyacrylate or carbomethoxycellulose materials or the like or any
material capable of absorbing many times its own weight in liquid.
In some embodiments, the material can absorb more than five times
its own weight of 0.9% W/W saline, etc. In some embodiments, the
material can absorb more than 15 times its own weight of 0.9% W/W
saline, etc. In some embodiments, the material is capable of
absorbing more than 20 times its own weight of 0.9% W/W saline,
etc. Preferably, the material is capable of absorbing more than 30
times its own weight of 0.9% W/W saline, etc. The absorbent layer
3430 can have one or more through holes 3431 located so as to
underlie the suction port.
[0191] Some embodiments of the present disclosure may employ a
masking or obscuring layer 3420 to help reduce the unsightly
appearance of a dressing 3400 during use due to the absorption of
wound exudate. The obscuring layer 3420 may be a colored portion of
the absorbent material, or may be a separate layer that covers the
absorbent material. The obscuring layer 3420 may be one of a
variety of colors such as blue, orange, yellow, green, or any color
suitable for masking the presence of wound exudate in the dressing
3400. For example, a blue obscuring layer 3420 may be a shade of
blue similar to the shade of blue commonly used for the material of
medical gowns, scrubs, and drapes. Some embodiments of the
obscuring layer 3420 may comprise polypropylene spunbond material.
Further, some embodiments of the obscuring layer 3420 may comprise
a hydrophobic additive or coating. Other embodiments may comprise a
thin fibrous sheet of 60, 70, or 80 gsm.
[0192] The obscuring layer may comprise at least one viewing window
3422 configured to allow a visual determination of the saturation
level of the absorbent layer. The at least one viewing window 3422
may comprise at least one aperture made through the obscuring
layer. The at least one viewing window 3422 may comprise at least
one uncolored region of the obscuring layer. Some embodiments of
the obscuring layer may comprise a plurality of viewing windows or
an array of viewing windows, as discussed above with respect to
FIGS. 25-32.
[0193] The masking capabilities of the obscuring layer 3420 should
preferably only be partial, to allow clinicians to access the
information they require by observing the spread of exudate across
the dressing surface. A obscuring layer 3420 may be partial due to
material properties allowing wound exudate to slightly alter the
appearance of the dressing or due to the presence of at least one
viewing window 3422 in a completely obscuring material. The partial
masking nature of the obscuring layer 3420 enables a skilled
clinician to perceive a different colour caused by exudate, blood,
by-products etc. in the dressing allowing for a visual assessment
and monitoring of the extent of spread across the dressing.
However, since the change in colour of the dressing from its clean
state to a state with exudate contained is only a slight change,
the patient is unlikely to notice any aesthetic difference.
Reducing or eliminating a visual indicator of wound exudate from a
patient is likely to have a positive effect on their health,
reducing stress for example.
[0194] Tests performed upon various dressings with respect to the
transmittance properties of the dressing indicate the ability of
various samples to mask colour. The ability to mask colour may be
calculated, for example, by measuring the reduction in absorption
of light radiation at particular wavelengths. The tests utilized a
UV-Vis spectrophotometer Jasco with integrating sphere, with a
scanning range 340 to 800 nm, bandwidth 5 nm and 1000 nm/sec
scanning speed. The data labelled black background represents the
extreme of exudate colour (the most colour an exudate might
have)--the highest level of radiation absorbed and the least amount
of radiation reflected from the sample. The data for white
background represents the upper limit for total masking--generally
the lowest level of radiation absorbed and the highest level of
reflection. Sample 1 was a tinted polymer film placed over a black
background, which was judged not to sufficiently mask the black
background (representing wound exudate) satisfactorily. Sample 2
was a sheet of 3-dimensional spacer fabric (Baltex 3D) placed over
a black background, and was judged to provide adequate masking of
the black background. Sample 3 was a sheet of non-woven material
dyed green placed over a black background, and provided complete
masking of the black background.
[0195] Wound exudate may have dark yellow, red and/or brown tones.
Therefore, to appropriately mask these colours, an obscuring layer
3420 would preferably shield light wavelengths of below 600 nm.
[0196] Measuring the reduction in absorption of light radiation at
particular wavelengths may be performed by calculating:
% reduction=(A.sub.background-A.sub.sample placed on
background)/(A.sub.background).times.100
[0197] where A is the absorption of light radiation at the
particular wavelength.
[0198] Using this formula, using light at a wavelength of 460 nm,
the percentage of absorption reduction was calculated as shown in
Table 3 below.
TABLE-US-00001 TABLE 3 Absorption reduction Appropriate masking
Sample at 460 nm observed Sample 1 34% No Sample 2 77% Yes -
partial Sample 3 69% Yes - complete
[0199] It has been found that materials that reduce light
absorption by about 50% or more will provide enough partial or
complete masking of wound exudate (as judged by the inventors). Of
course a complete masking element would preferably require a means
for a clinician to judge the spread of wound exudate in the
dressing below the obscuring layer 3420, e.g. the masking element
not completely covering the entire dressing. For example, as
described above with respect to FIGS. 25-33, a plurality of viewing
windows may be provided in the obscuring layer 3420 such that the
spread of exudate in the dressing below may be adequately assessed.
Alternatively a partial masking element may allow a clinician to
judge the spread of exudate in the dressing below without
additional means.
[0200] It will be understood that the wetting of a masking material
(by exudate for example) will also affect the masking performance
of the masking element, since hydrophilic materials will allow
chromophore-carrying species to travel through them more easily. As
such, the absorption reduction rate should also be tested on wet
materials.
[0201] The above-mentioned Samples 1, 2 and 3 were also tested for
their masking properties by measuring CIE L*a*b* values (a known
3-dimensional model for representing colour space). The analysis
employed Jasco software using the range 380 to 780 nm, stard
observed 2 (deg), lightsource D65, colour matching JIS
Z8701-1999.
[0202] Table 4 below shows the L*a*b* values found when Samples 1,
2 and 3 were respectively placed over a black background. The
results for the black background alone and a white background are
also shown.
TABLE-US-00002 TABLE 4 CIE L*a*b* Appropriate values recorded
masking Sample L* a* b* observed? Black 0 0 0 n/a background Sample
1 (on 36.59 3.76 -1.80 No black) Sample 2 (on 71.76 -0.20 -1.08 Yes
- partial black) Sample 3 (on 70.64 -0.25 -1.23 Yes - complete
black) White 100 0 0 n/a background
[0203] Generally, samples which lead to an increase in L* value
will provide a lighter colour tone than the reference surface,
which is the main contributor to masking a dark colour. From the
values above, apt partial masking materials will yield an L* value
above 50, or more aptly above 70.
[0204] However, completely opaque masking layers, such as for
example a tinted polymeric film, may cover the area to be masked
with a darker tone altogether, in which case the measure of L* is
not relevant. Once again these values should also be considered on
wet material, for the reasons stated above.
[0205] In addition to transmittance properties, the color of the
obscuring layer 3420 may affect the masking ability of the layer.
In liquid permeable embodiments of the obscuring layer, various
colors are suitable for masking the usual colors of wound exudate,
while other colors may not provide optimal masking of the exudate.
For example, with reference to the CIE chromaticity diagram
illustrated in FIG. 38, some embodiments of the obscuring layer, in
a dry state, may be configured to yield a CIE y value of 0.4 or
less and a CIE x value of 0.5 or less. Some embodiments of the
obscuring layer, in a dry state, may have a color of Bg, gB, B, pB,
bP, P, rP, pPk, RP, O, rO, or yO on the CIE x, y chromaticity
diagram. It will be appreciated that liquid impermeable embodiments
of the obscuring layer may be configured with any color.
[0206] The obscuring layer 3420 can have one or more through holes
located so as to underlie the suction port. Some embodiments may
have a maltese cross 3421 or other shaped cutout underlying the
suction port, wherein the diameter of the maltese cross 3421 is
greater than the diameter of the port. This may allow a clinician
to easily asses the amount of wound exudate absorbed into the
layers beneath the port.
[0207] The dressing 3400 may also comprise a backing layer, or
cover layer 3410 extending across the width of the wound dressing.
The cover layer 3410 may be gas impermeable but moisture vapor
permeable. Some embodiments may employ a polyurethane film (for
example, Elastollan SP9109) or any other suitable material. For
example, certain embodiments may comprise translucent or
transparent 30 gsm EU33 film. The cover layer 3410 may have a
pressure sensitive adhesive on the lower side, thereby creating a
substantially sealed enclosure over the wound in which negative
pressure may be established. The cover layer can protect the wound
as a bacterial barrier from external contamination, and may allow
liquid from wound exudates to be transferred through the layer and
evaporated from the film outer surface.
[0208] The cover layer 3410 can have an orifice 3411 located so as
to underlie the suction port. The orifice 3411 may allow
transmission of negative pressure through the cover layer 3410 to
the wound enclosure. The port may be adhered and sealed to the
cover film using an adhesive such as an acrylic, cyanoacrylate,
epoxy, UV curable or hot melt adhesive. Some embodiments may have a
plurality of orifices for the attachment of multiple ports or other
sources of negative pressure or other mechanisms for distributing
fluid.
[0209] FIG. 34B illustrates a cross sectional view of the wound
dressing 3400, displaying an embodiment of the relative thicknesses
of layers of the dressing 3400. In some embodiments, the wound
contact layer 3460 may be flat and the top film layer 3410 may be
contoured over the inner layers of the dressing 3400. The spacer
layer 3450 may be half as thick as the acquisition distribution
layer 3440 in some embodiments. In some embodiments, the absorbent
layer 3430 may be about 1.5 times thicker than the spacer layer
3450. The obscuring layer 3420 may be about half the thickness of
the spacer layer 3450.
[0210] FIG. 35 illustrates a perspective exploded view of an
embodiment of a flexible port or fluidic connector 3500 that may be
used to connect any of the wound dressings described herein to a
source of negative pressure. The port 3500 comprises a top layer
3510, a spacer layer 3520, a filter element 3530, a bottom layer
3540, and a conduit 3550. The conduit optionally comprises a
connector 3560. The distal end of the port 3500 (the end
connectable to the dressing 3400) is depicted as having an enlarged
circular shape, although it will be appreciated that any suitable
shape may be used and that the distal end need not be enlarged. For
example, the distal end can have any of the shapes shown in FIGS.
23A and 23B above. The distal end can also have the shape shown in
FIGS. 3A-3C of Provisional Application Ser. No. 61/650,904, filed
May 23, 2012, incorporated by reference herein and included as an
appendix.
[0211] The bottom layer 3540 may comprise an elongate bridge
portion 3544, an enlarged (e.g., rounded or circular) sealing
portion 3545, and an orifice 3541. In some embodiments a plurality
of orifices may be provided in the bottom layer. Some embodiments
of the rounded sealing portion 3545 may comprise a layer of
adhesive, for example a pressure sensitive adhesive, on the lower
surface for use in sealing the port 3500 to a dressing. For
example, the port may be sealed to the cover layer 3410 of the
dressing in FIG. 34. The orifice 3541 in the bottom layer 3540 of
the port 3500 may be aligned with the orifice 3411 in the cover
layer 3410 of the dressing 3400 in order to transmit negative
pressure through the dressing 3400 and into a wound site.
[0212] The top layer 3515 may be substantially the same shape as
the bottom layer in that it comprises an elongate bridge 3514 and
an enlarged (e.g., rounded or circular) portion 3515. The top layer
3515 and the bottom layer 3545 may be sealed together, for example
by heat welding. In some embodiments, the bottom layer 3545 may be
substantially flat and the top layer 3515 may be slightly larger
than the bottom layer 3545 in order to accommodate the height of
the spacer layer 3520 and seal to the bottom layer 3545. In other
embodiments, the top layer 3515 and bottom layer 3145 may be
substantially the same size, and the layers may be sealed together
approximately at the middle of the height of the spacer layer 3520.
In some embodiments, the elongate bridge portions 3544, 3514 may
have a length of 10 cm (or about 10 cm) or more, more preferably a
length of 20 cm (or about 20 cm) or more and in some embodiments,
may be about 27 cm long. In some embodiments, the elongate bridge
portions may have a width of between 1 cm and 4 cm (or between
about 1 cm and about 4 cm), and in one embodiment, is about 2.5 cm
wide. The ratio of the length of the elongate bridge portions 3544,
3514 to their widths may in some embodiments exceed 6:1, and may
more preferably exceed 8:1 or even 10:1. The diameter of the
circular portion 3545, 3515 may be about 3.5 cm in some
embodiments.
[0213] The bottom and top layers may comprise at least one layer of
a flexible film, and in some embodiments may be transparent. Some
embodiments of the bottom layer 3540 and top layer 3515 may be
polyurethane, and may be liquid impermeable.
[0214] The port 3500 may comprise a spacer layer 3520, such as the
3D fabric discussed above, positioned between the lower layer 3540
and the top layer 3510. The spacer layer 3520 may be made of any
suitable material, for example material resistant to collapsing in
at least one direction, thereby enabling effective transmission of
negative pressure therethrough. The spacer layer 3520 may comprise
an enlarged (e.g., rounded or circular) portion 3525, and may
optionally include a fold 3521. In some embodiments, the elongate
bridge portion may have dimensions in the same ranges as the bridge
portions of the upper and lower layers described above though
slightly smaller, and in one embodiment is about 25.5 cm long and
1.5 cm wide. Similarly, the diameter of the circular portion 3525
may be slightly smaller than the diameters of the enlarged ends
3545, 3515, and in one embodiment is about 2 cm. Some embodiments
of the spacer layer 3520 may have adhesive on one or both of its
proximal and distal ends (e.g., one or more dabs of adhesive) in
order to secure the spacer layer 3520 to the top layer 3510 and/or
the bottom layer 3540. Adhesive may also be provided along a
portion or the entire length of the spacer layer. In other
embodiments, the spacer layer 3520 may be freely movable within the
sealed chamber of the top and bottom layers.
[0215] The fold 3521 of the spacer fabric may make the end of the
port 3500 softer and therefore more comfortable for a patient, and
may also help prevent the conduit 3550 from blockage. The fold 3521
may further protect the end of the conduit 3550 from being occluded
by the top or bottom layers. The fold 3521 may, in some
embodiments, be between 1 cm and 3 cm (or between about 1 cm and
about 3 cm) long, and in one embodiment is 2 cm (or about 2 cm)
long. The spacer fabric may be folded underneath itself, that is
toward the bottom layer 3540, and in other embodiments may be
folded upward toward the top layer 3510. Other embodiments of the
spacer layer 3520 may contain no fold. A slot or channel 3522 may
extend perpendicularly away from the proximal end of the fold 3521,
and the conduit 3550 may rest in the slot or channel 3522. In some
embodiments the slot 3522 may extend through one layer of the fold,
and in others it may extend through both layers of the fold. The
slot 3522 may, in some embodiments, be 1 cm (or about 1 cm) long.
Some embodiments may instead employ a circular or elliptical hole
in the fold 3521. The hole may face proximally so that the conduit
3550 may be inserted into the hole and rest between the folded
layers of spacer fabric. In some embodiments, the conduit 3550 may
be adhered to the material of the fold 3521, while in other
embodiments it may not.
[0216] The port 3500 may have a filter element 3530 located
adjacent the orifice 3541, and as illustrated is located between
the lower layer 3540 and the spacer layer 3520. As illustrated, the
filter element 3530 may have a round or disc shape. The filter
element 3530 is impermeable to liquids, but permeable to gases. The
filter element 3530 can act as a liquid barrier, to substantially
prevent or inhibit liquids from escaping from the wound dressing,
as well as an odor barrier. The filter element 3530 may also
function as a bacterial barrier. In some embodiments, the pore size
of the filter element 3530 can be approximately 0.2 .mu.m. Suitable
materials for the filter material of the filter element include 0.2
micron Gore.TM. expanded PTFE from the MMT range, PALL
Versapore.TM. 200R, and Donaldson.TM. TX6628. The filter element
3530 thus enables gas to be exhausted through the orifice. Liquid,
particulates and pathogens however are contained in the dressing.
Larger pore sizes can also be used but these may require a
secondary filter layer to ensure full bioburden containment. As
wound fluid contains lipids it is preferable, though not essential,
to use an oleophobic filter membrane for example 1.0 micron MMT-332
prior to 0.2 micron MMT-323. This prevents the lipids from blocking
the hydrophobic filter. In some embodiments, the filter element
3530 may be adhered to one or both of top surface of the bottom
layer 3540 and the bottom surface of the spacer layer 3520 using an
adhesive such as, but not limited to, a UV cured adhesive. In other
embodiments, the filter 3530 may be welded to the inside of the
spacer layer 3520 and to the top surface of the bottom layer 3540.
The filter may also be provided adjacent the orifice on a lower
surface of the bottom layer 3540. Other possible details regarding
the filter are disclosed in U.S. Patent Pub. No. 2011/0282309 and
incorporated by reference herein.
[0217] The proximal end of the port 3500 may be connected to the
distal end of a conduit 3550. The conduit 3550 may comprise one or
more circular ribs 3551. The ribs 3551 may be formed in the conduit
3550 by grooves in a mold during the manufacturing of the conduit.
During heat welding of the upper and lower layers 3515, 3545 melted
material from those layers may flow around the ribs 3551,
advantageously providing a stronger connection between the conduit
3550 and the layers. As a result, it may be more difficult to
dislodge the conduit 3550 out from between the layers during use of
the port 3500.
[0218] The proximal end of the conduit 3550 may be optionally
attached to a connector 3560. The connector 3560 may be used to
connect the port 3500 to a source of negative pressure, or in some
embodiments to an extension conduit which may in turn be connected
to a source of negative pressure. The distal end of the conduit
3550, which is inserted into the spacer layer 3520, may be shaped
in such a way to reduce the possibility of occlusion.
[0219] FIG. 36 illustrates an embodiment of a wound dressing 3610
with a flexible port 3620 such as described with respect to FIG. 35
attached. The port 3620 comprises a conduit 3630 and a connector
3640 for connecting the port to a source of negative pressure or to
an extension conduit. The dressing 3610 comprises an obscuring
layer with one row of eight holes in a linear arrangement, and is
described above in more detail with respect to FIG. 25. Although in
this depiction the port 3620 is connected over a circular window in
the obscuring layer of the dressing 3610, in other embodiments the
port 3620 may be connected over a maltese cross in the obscuring
layer. In some embodiments, the maltese cross may be of a larger
diameter than the port and may be at least partially viewable after
the port is attached to the dressing.
[0220] FIG. 37A illustrates a perspective view of an embodiment of
the dressing. Although the configuration as depicted is similar to
the embodiment of FIG. 29B, the dressing can have any of the
constructions of different layers previously described. Conduit
3710 is connected to the dressing 3700 via port 3720, however other
embodiments of ports may be connected to the dressing, for example
the flexible port of FIG. 35.
[0221] FIG. 37B illustrates a bottom view of the dressing 3700. The
view illustrates a transmission layer 3730 and an acquisition
distribution layer 3740, which may be similar to the transmission
layer 3450 and acquisition distribution layer 3440 of FIGS. 34A and
34B. In some embodiments, the perimeter of the transmission layer
3730 may be slightly smaller than the perimeter of the acquisition
distribution layer 3740. The view also illustrates one embodiment
of a release layer 3750 similar to release layer 3480 previously
described for use in protecting the adhesive side of the wound
contact layer. The release layer 3750 as illustrated is made of two
separate layers of material that can be removed from the adhesive
side of the wound contact layer by pulling on flaps attached to the
release layer.
[0222] It will be of course appreciated that other dressing
configurations are possible other than a narrow central portion
configuration, a three-lobed configuration, a four-lobed
configuration, including, for example, hexagonal or circular shaped
backing layers for use in dressings. As illustrated in FIGS. 15A-B,
these embodiments may also comprise various configurations of
slits, described previously, so as to enhance conformability of the
dressing in non-planar wounds. Also, as described previously, the
absorbent layers of these embodiments may be colored or obscured
with an obscuring layer, and optionally provided with one or more
viewing windows. Further, the domed ports of these embodiments may
also be replaced with one or more fluidic connectors of the type
described below in FIGS. 23A-B, and vice versa. Additionally, all
features and structures described for wound dressings with the
waisted portion configuration can be incorporated into any shape or
dressing configuration as described herein.
[0223] Features, materials, characteristics, or groups described in
conjunction with a particular aspect, embodiment, or example are to
be understood to be applicable to any other aspect, embodiment or
example described herein unless incompatible therewith. All of the
features disclosed in this specification (including any
accompanying claims, abstract and drawings), and/or all of the
steps of any method or process so disclosed, may be combined in any
combination, except combinations where at least some of such
features and/or steps are mutually exclusive. The protection is not
restricted to the details of any foregoing embodiments. The
protection extends to any novel one, or any novel combination, of
the features disclosed in this specification (including any
accompanying claims, abstract and drawings), or to any novel one,
or any novel combination, of the steps of any method or process so
disclosed.
[0224] While certain embodiments have been described, these
embodiments have been presented by way of example only, and are not
intended to limit the scope of protection. Indeed, the novel
methods and systems described herein may be embodied in a variety
of other forms. Furthermore, various omissions, substitutions and
changes in the form of the methods and systems described herein may
be made. Those skilled in the art will appreciate that in some
embodiments, the actual steps taken in the processes illustrated
and/or disclosed may differ from those shown in the figures.
Depending on the embodiment, certain of the steps described above
may be removed, others may be added. Furthermore, the features and
attributes of the specific embodiments disclosed above may be
combined in different ways to form additional embodiments, all of
which fall within the scope of the present disclosure.
[0225] Although the present disclosure includes certain
embodiments, examples and applications, it will be understood by
those skilled in the art that the present disclosure extends beyond
the specifically disclosed embodiments to other alternative
embodiments and/or uses and obvious modifications and equivalents
thereof, including embodiments which do not provide all of the
features and advantages set forth herein. Accordingly, the scope of
the present disclosure is not intended to be limited by the
specific disclosures of preferred embodiments herein, and may be
defined by claims as presented herein or as presented in the
future.
[0226] The reader's attention is directed to all papers and
documents which are filed concurrently with or previous to this
specification in connection with this application and which are
open to public inspection with this specification, and the contents
of all such papers and documents are incorporated herein by
reference.
* * * * *