U.S. patent application number 17/074024 was filed with the patent office on 2021-02-04 for drape having microstrain inducing projections for treating a wound site.
The applicant listed for this patent is KCI Licensing, Inc.. Invention is credited to Richard Daniel John COULTHARD, Christopher Brian LOCKE, Timothy Mark ROBINSON, Aidan Marcus TOUT.
Application Number | 20210030598 17/074024 |
Document ID | / |
Family ID | 1000005152551 |
Filed Date | 2021-02-04 |
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United States Patent
Application |
20210030598 |
Kind Code |
A1 |
LOCKE; Christopher Brian ;
et al. |
February 4, 2021 |
DRAPE HAVING MICROSTRAIN INDUCING PROJECTIONS FOR TREATING A WOUND
SITE
Abstract
Systems and apparatuses for administering reduced pressure
treatment to a tissue site include a reduced pressure source, a
drape having a plurality of projections for contacting the tissue
site, and an adhesive connected to at least a portion of the drape
for sealing the drape to a portion of a patient's intact
epidermis.
Inventors: |
LOCKE; Christopher Brian;
(Bournemouth, GB) ; COULTHARD; Richard Daniel John;
(Verwood, GB) ; ROBINSON; Timothy Mark;
(Shillingstone, GB) ; TOUT; Aidan Marcus;
(Alderbury, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KCI Licensing, Inc. |
San Antonio |
TX |
US |
|
|
Family ID: |
1000005152551 |
Appl. No.: |
17/074024 |
Filed: |
October 19, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15234624 |
Aug 11, 2016 |
10849791 |
|
|
17074024 |
|
|
|
|
13311893 |
Dec 6, 2011 |
9440010 |
|
|
15234624 |
|
|
|
|
61420678 |
Dec 7, 2010 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61L 31/06 20130101;
A61L 15/00 20130101; A61F 13/00017 20130101; A61M 1/0092 20140204;
A61F 2013/00536 20130101; A61M 1/00 20130101; A61F 13/00042
20130101; A61M 1/0088 20130101; A61F 13/00034 20130101; A61F
13/00068 20130101; A61L 15/16 20130101; A61M 1/0084 20130101; A61F
13/00046 20130101; A61M 1/0023 20130101; A61M 1/34 20130101; A61F
13/00 20130101; A61F 13/00008 20130101; A61F 13/00038 20130101 |
International
Class: |
A61F 13/00 20060101
A61F013/00; A61L 15/16 20060101 A61L015/16; A61L 15/00 20060101
A61L015/00; A61M 1/34 20060101 A61M001/34; A61M 1/00 20060101
A61M001/00; A61L 31/06 20060101 A61L031/06 |
Claims
1. A system for providing reduced pressure wound therapy to a
tissue site, comprising: a drape configured to be disposed over the
tissue site to create a sealed space between the drape and the
tissue site; a reduced pressure source in fluid communication with
the sealed space; a sensor in fluid communication with the sealed
space; and a processing unit operatively coupled to the sensor;
wherein the processing unit is configured to determine a real-time
rate of pressure decay based on data from the sensor.
2. The system of claim 1, wherein the decay is determined by
measuring an amount of time required for pressure at the sealed
space to drop below a threshold pressure.
3. The system of claim 1, further comprising a vent fluidly coupled
to the sealed space by a conduit.
4. The system of claim 3, wherein the decay in reduced pressure is
determined by measuring a reduction in a flow rate in the conduit
over a selected amount of time after opening the vent.
5. The system of claim 1, wherein the processing unit is configured
to send an alert signal when the drape needs to be changed.
6. The system of claim 1, wherein the processing unit is configured
to: calculate a pressure-time curve based on a time required to
reach a set pressure at the sealed space; determine, based on a
shape of the pressure-time curve, whether the drape needs to be
changed due to an accumulation of slough or a growth of granulation
tissue.
7. The system of claim 1, wherein the drape comprises a
substantially gas impermeable, flexible sheet.
8. The system of claim 7, wherein the drape comprises a plurality
of projections extending from a tissue-facing side.
9. The system of claim 8, wherein the plurality of projections are
dimensioned to provide deformation and microstrain at the tissue
site when reduced pressure is applied to the sealed space.
10. The system of claim 8, wherein the tissue-facing side of the
drape comprises an inner portion and an outer portion surrounding
the inner portion, wherein the plurality of projections extend from
the inner portion.
11. The system of claim 10, wherein the outer portion is configured
to contact intact epidermis.
12. The system of claim 8, wherein the plurality of projections
form a plurality of channels between the plurality of
projections.
13. The system of claim 12, wherein the plurality of channels are
configured to allow reduced pressure to be distributed across the
tissue site when reduced pressure is applied to the sealed
space.
14. The system of claim 12, wherein the plurality of channels are
configured to allow fluid to flow around the plurality of
projections.
15. The system of claim 8, wherein the plurality of projections are
formed from a flexible material.
16. The system of claim 8, wherein the plurality of projections are
formed from a silicone material.
17. The system of claim 8, wherein the plurality of projections are
formed from a semi-gas permeable material.
18. The system of claim 8, wherein the plurality of projections are
formed from a rigid material.
19. The system of claim 8, wherein the plurality of projections are
solid.
20. The system of claim 8, wherein the plurality of projections are
hollow.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 15/234,624, filed Aug. 11, 2016, which is a
continuation of U.S. patent application Ser. No. 13/311,893, filed
Dec. 6, 2011, now U.S. Pat. No. 9,440,010, which claims the
benefit, under 35 USC .sctn. 119(e), of U.S. Provisional Patent
Application No. 61/420,678, filed Dec. 7, 2010, which are hereby
incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] The present invention relates generally to reduced pressure
treatment systems and more particularly to a drape having
microstrain inducing projections for treating a wound site.
2. Description of Related Art
[0003] Clinical studies and practice have shown that providing a
reduced pressure in proximity to a tissue site augments and
accelerates the growth of new tissue at the tissue site. The
applications of this phenomenon are numerous, but one particular
application of reduced pressure involves treating wounds. This
treatment (frequently referred to in the medical community as
"negative pressure wound therapy," "reduced pressure therapy," or
"vacuum therapy") provides a number of benefits, including
migration of epithelial and subcutaneous tissues, improved blood
flow, and micro-deformation of tissue at the wound site. Together
these benefits result in increased development of granulation
tissue and faster healing times. Typically, reduced pressure is
applied by a reduced pressure source to tissue through a porous pad
or other manifold device. The porous pad contains cells or pores
that are capable of distributing reduced pressure to the tissue and
channeling fluids that are drawn from the tissue. The porous pad
often is incorporated into a dressing having other components that
facilitate treatment.
SUMMARY
[0004] The problems presented by existing reduced pressure
treatment systems are solved by the systems and methods of the
illustrative embodiments described herein. In one illustrative
embodiment, an apparatus for treating a wound site on a patient
includes a drape for positioning over a wound site. The drape
includes a substantially gas impermeable, flexible mat having a
first side and a second, wound-facing side that is configured to
extend beyond the wound site to contact an intact portion of the
patient's epidermis. The drape further includes a plurality of
projections extending from at least a portion of the second side of
the substantially gas impermeable, flexible mat.
[0005] In another illustrative embodiment, an apparatus for
treating a wound site on a patient includes a single-layer drape
for positioning over the wound site configured to (i) extend beyond
the wound site to contact a portion of the patient's intact
epidermis for sealing the wound site and (ii) promote granulation
at the wound site. The drape includes a substantially gas
impermeable, flexible sheet having a first side and a second,
wound-facing side. The first side of the flexible sheet is
substantially smooth and the second side of the sheet has a
plurality of projections for promoting granulation formation.
[0006] In yet another illustrative embodiment, an apparatus for
treating a wound site on a patient includes a multi-layer drape for
positioning over a wound site configured to both seal the wound
site and promote granulation at the wound site. The drape includes
a first layer and a second layer connected to the first layer
forming an inner chamber between the first layer and the second
layer. The second layer has a first plurality of sections with a
thickness, t1, and a second plurality of sections with a thickness,
t2, less than the thickness, t1. The second plurality of sections
are configured to form a plurality of projections for promoting
granulation at the wound site in the presence of a biasing
force.
[0007] In an illustrative embodiment, an apparatus for treating a
wound site on a patient includes a multi-layer drape for
positioning over a wound site. The drape is configured to both seal
the wound site and promote granulation at the wound site and
includes a first layer and a second layer. The second layer is
connected to the first layer forming an inner chamber between the
first layer and the second layer. The second layer has a plurality
of protrusions extending from a tissue-facing side of the second
layer in the presence of a biasing force.
[0008] In another illustrative embodiment, a reduced pressure
treatment system for administering reduced pressure treatment to a
tissue site includes a reduced pressure source and a drape in fluid
communication with the reduced pressure source to distribute a
reduced pressure to the tissue site. The drape includes a
substantially gas impermeable, flexible mat having a first side and
a second, tissue-facing side that is configured to extend beyond
the wound site to contact an intact portion of the patient's
epidermis. The drape further includes a plurality of projections
extending from at least a portion of the second side of the
substantially gas impermeable, flexible mat.
[0009] In yet another illustrative embodiment, a reduced pressure
treatment system for administering reduced pressure treatment to a
tissue site includes a reduced pressure source and a single-layer
drape positioned over the tissue site and coupled to the reduced
pressure source to distribute a reduced pressure to the tissue
site. The drape is configured to (i) extend beyond the tissue site
to contact a portion of the patient's intact epidermis for sealing
the tissue site and (ii) promote granulation at the tissue site.
The drape includes a substantially gas impermeable, flexible sheet
having a first side and a second, tissue-facing side such that the
first side is substantially smooth and the second side includes a
plurality of projections for promoting granulation formation.
[0010] In another illustrative embodiment, a reduced pressure
treatment system for administering reduced pressure treatment to a
tissue site includes a reduced pressure source, a positive pressure
source, and a multi-layer drape fluidly coupled to the reduced
pressure source and the positive pressure source. The multi-layer
drape is positioned over the tissue site and configured to both
seal the tissue site and promote granulation at the tissue site.
The drape includes a first layer and a second layer connected to
the first layer to form an inner chamber between the first layer
and the second layer. The second layer has a first plurality of
sections with a thickness, t1, and a second plurality of sections
with a thickness, t2, less than the thickness, t1. The second
plurality of sections are configured to form a plurality of
projections for promoting granulation at the wound site in the
presence of a positive pressure.
[0011] In yet another illustrative embodiment, a reduced pressure
treatment system for administering reduced pressure treatment to a
tissue site includes a reduced pressure source, a drape having a
plurality of projections for contacting the tissue site, and an
adhesive connected to at least a portion of the drape for sealing
the drape to a portion of a patient's intact epidermis.
[0012] Other objects, features, and advantages of the illustrative
embodiments will become apparent with reference to the drawings and
detailed description that follow.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 illustrates a perspective view, with a portion shown
in cross-section, of a reduced pressure treatment system including
a dressing according to an illustrative embodiment;
[0014] FIG. 2A illustrates a cross-sectional view of an
illustrative embodiment of a dressing for use in the reduced
pressure treatment system of FIG. 1 without reduced pressure being
applied;
[0015] FIG. 2B illustrates a cross-sectional view of an
illustrative embodiment of a dressing for use in the reduced
pressure treatment system of FIG. 1 with reduced pressure being
applied;
[0016] FIG. 3A illustrates a cross-sectional view of an
illustrative embodiment of a dressing for use in the reduced
pressure treatment system of FIG. 1 without reduced pressure being
applied;
[0017] FIG. 3B illustrates a cross-sectional view of an
illustrative embodiment of a dressing for use in the reduced
pressure treatment system of FIG. 1 with reduced pressure being
applied;
[0018] FIG. 4A illustrates a magnified view of a portion of the
dressing shown in FIG. 1 without reduced pressure being
applied;
[0019] FIG. 4B illustrates a magnified view of a portion of the
dressing shown in FIG. 1 with reduced pressure being applied;
[0020] FIG. 5 illustrates a cross-sectional view of an illustrative
embodiment of a dressing for use in the reduced pressure treatment
system of FIG. 1 with reduced pressure being applied;
[0021] FIG. 6 illustrates a cross-sectional view of an illustrative
embodiment of a dressing for use in the reduced pressure treatment
system of FIG. 1 with reduced pressure being applied;
[0022] FIG. 7A illustrates a cross-sectional view of an
illustrative embodiment of a dressing for use in the reduced
pressure treatment system of FIG. 1 without reduced pressure being
applied;
[0023] FIG. 7B illustrates a cross-sectional view of an
illustrative embodiment of a dressing for use in the reduced
pressure treatment system of FIG. 1 with reduced pressure being
applied;
[0024] FIG. 8A illustrates a magnified view of a portion of the
dressing shown in FIG. 7A; and
[0025] FIG. 8B illustrates a magnified view of a portion of the
dressing shown in FIG. 7B.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0026] In the following detailed description of several
illustrative embodiments, reference is made to the accompanying
drawings that form a part hereof, and in which is shown by way of
illustration specific preferred embodiments in which the invention
may be practiced. These embodiments are described in sufficient
detail to enable those skilled in the art to practice the
invention, and it is understood that other embodiments may be
utilized and that logical structural, mechanical, electrical, and
chemical changes may be made without departing from the spirit or
scope of the invention. To avoid detail not necessary to enable
those skilled in the art to practice the embodiments described
herein, the description may omit certain information known to those
skilled in the art. The following detailed description is,
therefore, not to be taken in a limiting sense, and the scope of
the illustrative embodiments are defined only by the appended
claims. Unless otherwise indicated, as used herein, "or" does not
require mutual exclusivity.
[0027] The term "reduced pressure" as used herein generally refers
to a pressure less than the ambient pressure at a tissue site that
is being subjected to treatment. In most cases, this reduced
pressure will be less than the atmospheric pressure at which the
patient is located. Alternatively, the reduced pressure may be less
than a hydrostatic pressure associated with tissue at the tissue
site. Although the terms "vacuum" and "negative pressure" may be
used to describe the pressure applied to the tissue site, the
actual pressure reduction applied to the tissue site may be
significantly less than the pressure reduction normally associated
with a complete vacuum. Reduced pressure may initially generate
fluid flow in the area of the tissue site. As the hydrostatic
pressure around the tissue site approaches the desired reduced
pressure, the flow may subside, and the reduced pressure is then
maintained. Unless otherwise indicated, values of pressure stated
herein are gauge pressures. Similarly, references to increases in
reduced pressure typically refer to a decrease in absolute
pressure, while decreases in reduced pressure typically refer to an
increase in absolute pressure.
[0028] The term "positive pressure" as used herein generally refers
to a pressure greater than the ambient pressure at a tissue site
that is being subjected to treatment. In some cases, this positive
pressure will be greater than the atmospheric pressure at which the
patient is located. Alternatively, the positive pressure may be
greater than a hydrostatic pressure associated with tissue at the
tissue site.
[0029] The tissue treatment systems and methods described in this
application improve the treatment of a tissue site by increasing or
improving granulation tissue development, thus allowing healing of
a wound that may not otherwise heal with traditional treatment
modalities, or in some cases, allowing an increased rate of healing
of a wound. Granulation may be promoted by exposing the tissue site
to micro-mechanical stresses and strains. The tissue site may also
be exposed to macro strains. While the creation of micro-mechanical
stresses and strains at a tissue site may be provided by applying a
reduced pressure to a sealed space adjacent the tissue site, the
system and methods described herein may also employ the use of
positive pressure or forces to create micro and macro stresses and
strains.
[0030] Referring to FIG. 1, an illustrative embodiment of a reduced
pressure treatment system 100 for treating a tissue site 102 on a
patient includes a dressing 103 placed proximate to the tissue site
102 and a therapy unit 104 fluidly coupled to the dressing 103. As
used herein, the term "tissue site" may refer to a wound, such as a
wound 106, or defect located on or within any tissue, including but
not limited to, bone tissue, adipose tissue, muscle tissue, neural
tissue, dermal tissue, vascular tissue, connective tissue,
cartilage, tendons, or ligaments. The term "tissue site" may
further refer to areas of any tissue that are not necessarily
wounded or defective, but are instead areas in which it is desired
to add or promote the growth of additional tissue. For example,
reduced pressure tissue treatment may be used in certain tissue
areas to grow additional tissue that may be harvested and
transplanted to another tissue location.
[0031] The dressing 103 includes a drape 108, having a plurality of
projections 112 extending from the drape 108 and positioned in
contact with the tissue site 102. The plurality of projections 112
are configured to create microstrain at the tissue site 102 when
reduced pressure is applied to stimulate the formation of
granulation tissue. The drape 108 is positioned over the tissue
site 102 to create a sealed space 114 between the drape 108 and the
tissue site 102. Thus, the drape 108 is configured to not only
create the sealed space 114, but to also stimulate the formation of
granulation at the tissue site 102.
[0032] The dressing 103 further includes a reduced pressure
interface 110 fluidly coupling the drape 108 to the therapy unit
104. The reduced pressure interface 110 is fluidly coupled to the
drape 108 to provide fluid access to the tissue site 102. The drape
108 includes an aperture 116 for providing fluid access to the
reduced pressure interface 110. A conduit 118 fluidly couples the
therapy unit 104 and the reduced pressure interface 110. The
reduced pressure interface 110 is capable of delivering reduced
pressure to the tissue site 102.
[0033] In one embodiment, the therapy unit 104 includes a fluid
containment member 122 in fluid communication with a reduced
pressure source 124. In the embodiment illustrated in FIG. 1, the
fluid containment member 122 is a collection canister that includes
a chamber for collecting fluids from the tissue site 102. The fluid
containment member 122 alternatively could be an absorbent material
or any other container, device, or material that is capable of
collecting fluid.
[0034] The conduit 118 may be a multi-lumen tube that is capable of
providing one or more conduits to deliver reduced pressure to the
drape 108 and one or more conduits to sense the amount of pressure
at the tissue site 102. Liquids or exudates communicated from the
drape 108 through the conduit 118 are removed from the conduit 118
and retained within the fluid containment member 122.
[0035] Referring still to FIG. 1, the reduced pressure source 124
may an electrically-driven vacuum pump. In another implementation,
the reduced pressure source 124 may instead be a manually-actuated
or manually-charged pump that does not require electrical power. In
one embodiment, the reduced pressure source 124 may be one or more
piezoelectric-actuated micropumps that may be positioned remotely
from the dressing 103, or at the dressing beneath or adjacent to
the drape 108. The reduced pressure source 124 instead may be any
other type of pump, or alternatively a wall suction port or air
delivery port such as those available in hospitals and other
medical facilities. The reduced pressure source 124 may be housed
within or used in conjunction with the therapy unit 104, which may
also contain sensors, processing units, alarm indicators, memory,
databases, software, display units, and user interfaces 126 that
further facilitate the application of reduced pressure treatment to
the tissue site 102. In one example, pressure-detection sensors
(not shown) may be disposed at or near the reduced pressure source
124. The pressure-detection sensors may receive pressure data from
the reduced pressure interface 110 via lumens in the conduit 118
that are dedicated to delivering reduced pressure data to the
pressure-detection sensors. The pressure-detection sensors may
communicate with a processing unit that monitors and controls the
reduced pressure that is delivered by the reduced pressure source
124.
[0036] The reduced pressure treatment system 100 may further
include a vent 120 in the conduit 118 configured to release the
reduced pressure at the tissue site 102 over a selected amount of
time. A sensor (not shown) positioned in the therapy unit 104 may
receive data from the vent 120. The sensor communicates with the
processing unit. The measurements from the sensor may be used by
the processing unit to determine a real-time rate of pressure decay
as the reduced pressure is released through the vent 120. Based on
repeated determinations of the real-time rate of pressure decay,
the processing unit is configured to determine whether the drape
108 needs to be replaced due to the growth of granulation tissue or
the accumulation of slough, i.e., dead tissue. More rapid rates of
pressure decay may indicate that the drape 108 needs to be
replaced. The decay of the reduced pressure may be determined in
several ways. For example, the decay may be determined by measuring
a reduction in the reduced pressure (i.e. increase in absolute
pressure) over a selected amount of time after opening the vent
120. As another example, the decay may be determined by measuring
the amount of time that is required for the reduced pressure to
drop to a threshold pressure. The decay in reduced pressure may
also be determined by measuring the reduction in the flow rate in
the conduit 118 over the selected amount of time after opening the
vent 120. Other methods of measuring the decay of reduced pressure
may also be used in a similar manner and are contemplated within
the scope of the illustrative embodiments.
[0037] The processing unit may send an alert signal to an alarm
when the drape 108 needs to be changed. In addition to the
processing unit sending an alert signal, the processing unit may
further indicate whether the drape 108 needs to be changed due to
an accumulation of slough, or whether the drape 108 needs to be
changed due to the growth of granulation tissue. The shape of the
pressure-time curve would distinguish between slough and
granulation tissue. Slough tends to be softer than granulation
tissue so when reduced pressure is applied to the drape 108, more
time would pass in reaching the set pressure when the drape 108 has
been placed adjacent to slough. More time would pass to reach the
set pressure due to the compression or creep of the slough as it is
squeezed between the drape 108 and the tissue site 102.
[0038] Referring now primarily to FIGS. 1-4B, the dressing 103, and
in particular the drape 108, will be described in more detail. The
drape 108, having a first side 128 and a second, tissue-facing side
130, is positioned over the tissue site 102. The plurality of
projections 112 are located on at least a portion of the second
side 130 of the drape 108 and are configured to create microstrain
at the tissue site 102 to promote granulation. As illustrated, the
drape 108 is comprised of a single layer. The drape 108 may be a
biomedical grade silicone or another flexible, biomedical material
such as polyurethane (PU), and particularly a hydrophilic
polyurethane, that may be easily removed from the tissue site 102
even in the presence of granulation formation. The materials used
to form the drape 108 may have elastic properties that assist in
preventing the tissue site 102 from contracting when the drape 108
is stretched into the tissue site 102 under reduced pressure. In
other words, the stretching of the drape 108 into the tissue site
102 creates macrostrain at the tissue site 102 that assists in
preventing wound contraction. In one embodiment, the material used
to form the drape 108 is substantially transparent to allow a
healthcare provider to inspect the tissue site 102 without removing
the drape 108. The drape 108 may be formed in a number of ways. In
specific, non-limiting examples, the drape 108 may be formed by
extrusion or molding.
[0039] The drape 108 may further include an adhesive layer (not
explicitly shown). A liner may cover the adhesive layer to protect
or preserve the adhesive layer prior to positioning the drape 108
at the tissue site 102. The adhesive layer is positioned on the
second side 130 of the drape 108. The adhesive layer may contact
only a portion of the second side 130 of the drape 108, or the
adhesive layer may contact the entire second side 130 of the drape
108. In one embodiment, the adhesive layer also contacts the
plurality of projections 112 located on the second side 130 of the
drape 108. In another embodiment, the adhesive layer only contacts
areas of the second side 130 of the drape 108 where the plurality
of projections 112 are absent. The adhesive layer may include
silver or a hydrogel. The adhesive layer may be configured so that
it dissolves in the presence of wound fluid. In another embodiment,
the adhesive layer may be inactive until it is contacted with a
catalyst. In operation, an area adjacent to the tissue site 102,
such as an intact portion of the patient's epidermis 132, may be
treated with a catalyst so that when the adhesive layer from the
drape 108 contacts the catalyst, the adhesive layer will adhere the
drape 108 to the area treated with a catalyst. In another example,
the catalyst may be applied directly to the adhesive layer prior to
positioning the drape 108 against the tissue site 102 and the
surrounding areas of the tissue site 102. In one specific,
non-limiting example, the catalyst is a platinum catalyst and the
drape 108 includes a silicone. When the platinum catalyst and the
silicone are brought into contact, the silicone polymerizes and
crosslinks. In another specific, non-limiting example, the catalyst
is a multivalent salt such as calcium chloride or zinc chloride.
The drape 108 includes a polymer solution such as a sodium salt of
an acrylic acid polymer. When the multivalent salt and the polymer
solution are brought in contact, the multivalent salt crosslinks
with the polymer.
[0040] The plurality of projections 112 may be flexible and may
further be formed from a substantially gas impermeable material
such as silicone. In one embodiment, the plurality of projections
112 may be formed from a semi-gas permeable material. Additionally,
the plurality of projections 112 may be rigid. As stated above, the
drape 108 may be made from silicone and since the plurality of
projections 112 are part of the drape 108, the plurality of
projections 112 may also be formed of silicone. In one embodiment,
the plurality of projections 112 are solid. In another embodiment,
the plurality of projections 112 are hollow. The plurality of
projections 112 may form a plurality of channels 137 to distribute
reduced pressure and allow for fluid flow between the plurality of
projections 112. The plurality of projections 112 are dimensioned
to provide local load points at the tissue site 102 sufficient to
create microstrain at the tissue site 102 for stimulating
granulation formation when reduced pressure is applied. The pattern
or position of the plurality of projections 112 on the drape 108
may be uniform or non-uniform. The plurality of projections 112 may
come in a number of shapes. In specific, non-limiting examples, the
plurality of projections 112 may be a spike, conical, pyramid,
dome, oblong, cylindrical, or rectangular shape. The shape of each
of the plurality of projections 112 may be the same, or the shapes
of each of the plurality of projections 112 may be different. In a
specific, non-limiting embodiment, the shapes will occupy a volume
described by cube volumes where the side of the cube would range
between approximately 0.2 millimeters (mm) to 1.5 mm. In one
embodiment, the spike shape would have a base length or diameter of
about 0.2 mm and a vertical height of between 0.4 mm to 0.8 mm. In
another embodiment, the cone shape would have a base diameter of
about 0.4 mm and a vertical height of between 0.4 mm to 1.2 mm. In
yet another embodiment, the dome shape would be a spherical cap or
parabolic shape with a base diameter ranging from about 0.4 mm to 1
mm.
[0041] Referring now specifically to FIGS. 2A and 2B, the dressing
103 is shown covering the tissue site 102. FIG. 2A illustrates the
drape 108 loosely placed over the tissue site 102 prior to the
application of reduced pressure. The drape 108 extends beyond the
perimeter of the tissue site 102 and contacts the intact portion of
the patient's epidermis 132. In this embodiment, FIGS. 2A and 2B
show the plurality of projections 112 contacting the intact portion
of the patient's epidermis 132. As previously discussed, an
adhesive layer seals the drape 108 to the intact portion of the
patient's epidermis 132, creating the sealed space 114. FIG. 2B
illustrates the drape 108 pressed into the tissue site 102 when
reduced pressure has been applied to the sealed space 114. Arrow
134 represents the downward force exerted on the drape 108 when
reduced pressure has been applied to the sealed space 114. The
reduced pressure applied to the sealed space 114 not only causes
the drape 108 to collapse into the tissue site 102 so that the
plurality of projections 112 press into the tissue site 102 and
create microstrain, the application of reduced pressure also causes
the tissue site 102 to be pulled or sucked into the plurality of
projections 112. The plurality of channels 137 formed by the
plurality of projections 112 allow (1) the reduced pressure to be
distributed across the tissue site 102 and (2) fluid to flow around
the plurality of projections 112.
[0042] Referring now specifically to FIGS. 3A and 3B, the dressing
103 is shown covering the tissue site 102. FIG. 3A illustrates the
drape 108 loosely placed over the tissue site 102 prior to the
application of reduced pressure. The drape 108 extends beyond the
perimeter of the tissue site 102 and contacts the intact portion of
the patient's epidermis 132. In this embodiment, FIGS. 3A and 3B
show the plurality of projections 112 being limited to an inner
portion 140 of the drape 108. Only an outer, smooth portion 142 of
the drape 108 contacts the intact portion of the patient's
epidermis 132. The outer portion 142 of the drape 108 may surround
the inner portion 140 of the drape 108. The adhesive layer seals
the drape 108 to the intact portion of the patient's epidermis 132,
creating the sealed space 114. FIG. 3B illustrates the drape 108
pressed into the tissue site 102 when reduced pressure has been
applied to the sealed space 114. The arrow 134 represents the
downward force exerted on the drape 108 when reduced pressure has
been applied to the sealed space 114. The reduced pressure applied
to the sealed space 114 not only causes the drape 108 to collapse
into the tissue site 102 so that the plurality of projections 112
press into the tissue site 102 and create microstrain, the
application of reduced pressure also causes the tissue site 102 to
be pulled or sucked into the plurality of projections 112. The
plurality of channels 137 formed by the plurality of projections
112 allow (1) the reduced pressure to be distributed across the
tissue site 102 and (2) fluid to flow around the plurality of
projections 112.
[0043] Referring now to FIGS. 4A and 4B, a detailed view of a
portion the drape 108 is presented. FIG. 4A is a detailed view of
the drape 108 positioned over to the tissue site 102 prior to
reduced pressure being applied. FIG. 4B is a detailed view of the
drape 108 positioned over to the tissue site 102 after reduced
pressure has been applied. As shown, the plurality of projections
112 are in the shape of a spike. However, as previously explained,
the plurality of projections 112 may take many shapes. The
plurality of projections 112 extend from or make up part of the
second side 130 of the drape 108. In FIG. 4A the plurality of
projections 112 rest against the tissue site 102 without exerting
any force on the tissue site 102 caused by reduced pressure. In
FIG. 4B, reduced pressure has been applied to the sealed space 114.
The arrow 134 represents the force exerted on the drape 108 and,
thus, the plurality of projections 112 from the reduced pressure.
The arrow 134 represents the force that causes the plurality of
projections 112 to be pushed into the tissue site 102. An arrow 136
represents the suction force applied to the tissue site 102 by way
of reduced pressure in the sealed space 114. The arrow 136
represents the force that causes the tissue site 102 to pull up
against the plurality of projections 112. Arrows 138 may represent
the flow of reduced pressure or fluids around the plurality of
projections 112 through the plurality of channels 137 formed by the
plurality of projections 112.
[0044] Referring now primarily to FIGS. 5 and 6, another embodiment
of a drape 208 for use in the reduced pressure treatment system 100
of FIG. 1 is presented. The drape 208 is similar to the drape 108
illustrated in FIGS. 1-4B, except the drape 208 comprises multiple
layers. The drape 208 includes a first layer 244 fixed to a second
layer 246. The second layer 246 may be referred to as a wound
filler. The first layer 244 may be fixed to the second layer 246 by
way of bond, weld, adhesive, heat process, or other known
connection means. The first layer 244 has a first side 248 and a
second side 250. The second layer 246 has a first side 252 and a
second side 254. The second side 248 of the first layer 244 is
fixed to the first side 252 of the second layer 246. The second
side 254 of the second layer 246 includes a plurality of
projections 212. The plurality of projections 212 are located on at
least a portion of the second side 254 of the second layer 246 of
the drape 208. The plurality of projections 212 are configured to
create microstrain at the tissue site 102 to promote granulation.
In one embodiment (not shown), the second layer may be comprised of
only the plurality of projections 212, such that each of the
plurality of projections 212 are individually fixed to the first
layer 244. The first and second layers 244, 246 of the drape 208
may be formed from a biomedical grade silicone or another flexible,
biomedical material such as polyurethane (PU). In particular the
first and second layers 244, 246 may be formed from a hydrophilic
polyurethane that may be easily removed from the tissue site 102
even in the presence of granulation formation. The first layer 244
may be formed from the same material or a different material as the
second layer 246. The materials used to form the drape 208 may have
elastic properties that assist in preventing the tissue site 102
from contracting when the drape 208 is stretched into the tissue
site 102 under reduced pressure. In other words, the stretching of
the drape 208 into the tissue site 102 creates macrostrain at the
tissue site 102 that assists in preventing wound contraction. In
one embodiment, the material or materials used to form the drape
208 are substantially transparent to allow a healthcare provider to
inspect the tissue site 102 without removing the drape 208. The
drape 208 may be formed in a number of ways. In specific,
non-limiting examples, the drape 208 may be formed by extrusion or
molding.
[0045] The drape 208 may further include an adhesive layer (not
explicitly shown). A liner may cover the adhesive layer to protect
or preserve the adhesive layer prior to positioning the drape 208
at the tissue site 102. The adhesive layer is positioned on the
second side 252 of the second layer 246 of the drape 208. The
adhesive layer may contact only a portion of the second side 252 of
the second layer 246, or the adhesive layer may contact the entire
second side 252 of the drape 208. In one embodiment, the adhesive
layer also contacts the plurality of projections 212 located on the
second side 252 of the second layer 246. In another embodiment, the
adhesive layer only contacts areas of the second side 252 of the
second layer 246 where the plurality of projections 212 are absent.
The adhesive layer may include silver or a hydrogel. The adhesive
layer may be configured so that it dissolves in the presence of
wound fluid. In another embodiment, the adhesive layer may be
inactive until it is contacted with a catalyst. In operation, an
area over to the tissue site 102, such as the intact portion of the
patient's epidermis 132, may be treated with a catalyst so that
when the adhesive layer from the drape 208 contacts the catalyst,
the adhesive layer will adhere the drape 208 to the area treated
with a catalyst. In another example, the catalyst may be applied
directly to the adhesive layer prior to positioning the drape 208
against the tissue site 102 and the surrounding areas of the tissue
site 102. In one specific, non-limiting example, the catalyst is a
platinum catalyst and the drape 208 includes a silicone. When the
platinum catalyst and the silicone are brought into contact, the
silicone polymerizes and crosslinks. In another specific,
non-limiting example, the catalyst is a multivalent salt such as
calcium chloride or zinc chloride. The drape 208 includes a polymer
solution such as a sodium salt of an acrylic acid polymer. When the
multivalent salt and the polymer solution are brought in contact,
the multivalent salt crosslinks with the polymer.
[0046] The plurality of projections 212 may be flexible and may
further be formed from a substantially gas impermeable material
such as silicone. A substantially gas impermeable material may also
include a semi-permeable material. In one embodiment, the plurality
of projections 212 are rigid. In one embodiment, the plurality of
projections 212 are solid. In another embodiment, the plurality of
projections 212 are hollow. The plurality of projections 212 form a
plurality of channels 237 to distribute reduced pressure and allow
for fluid flow between the plurality of projections 212. The
plurality of projections 212 are dimensioned to provide local load
points at the tissue site 102 sufficient to create microstrain at
the tissue site 102 for stimulating granulation formation. The
pattern or position of the plurality of projections 212 on the
drape 208 may be uniform or non-uniform. The plurality of
projections 212 may come in a number of shapes. In specific,
non-limiting examples, the plurality of projections 212 may be a
spike, conical, pyramid, dome, or oblong shape. The shape of each
of the plurality of projections 212 may be the same, or the shapes
of each of the plurality of projections 212 may be different.
[0047] Referring now specifically to FIG. 5, a dressing 203, which
includes the drape 208, is shown covering the tissue site 102. The
drape 208 extends beyond the perimeter of the tissue site 102 and
contacts the intact portion of the patient's epidermis 132. In this
embodiment, FIG. 5 shows the plurality of projections 212
contacting the intact portion of the patient's epidermis 132. As
previously discussed, an adhesive layer seals the drape 208 to the
intact portion of the patient's epidermis 132, creating a sealed
space 214. FIG. 5 illustrates the drape 208 pressed into the tissue
site 102 when reduced pressure has been applied to the sealed space
214. Arrow 234 represents the downward force exerted on the drape
208 when reduced pressure has been applied to the sealed space 214.
The reduced pressure applied to the sealed space 214 not only
causes the drape 208 to collapse into the tissue site 102 so that
the plurality of projections 212 press into the tissue site 102 and
create microstrain, the application of reduced pressure also causes
the tissue site 102 to be pulled or sucked into the plurality of
projections 212. The plurality of channels 237 formed by the
plurality of projections 212 allow (1) the reduced pressure to be
distributed across the tissue site 102 and (2) fluid to flow around
the plurality of projections 212.
[0048] Referring now specifically to FIG. 6, the dressing 203,
which includes the drape 208, is shown covering the tissue site
102. The drape 208 extends beyond the perimeter of the tissue site
102 and contacts the intact portion of the patient's epidermis 132.
In this embodiment, FIG. 6 shows the plurality of projections 212
being limited to an inner portion 240 of the drape 208. Only an
outer, smooth portion 242 of the drape 208 contacts the intact
portion of the patient's epidermis 132. The outer portion 242 of
the drape 208 may surround the inner portion 240 of the drape 208.
The adhesive layer seals the drape 208 to the intact portion of the
patient's epidermis 132, creating the sealed space 214. FIG. 6
illustrates the drape 208 pressed into the tissue site 102 when
reduced pressure has been applied to the sealed space 214. The
arrow 234 represents the downward force exerted on the drape 208
when reduced pressure has been applied to the sealed space 214. The
reduced pressure applied to the sealed space 214 not only causes
the drape 208 to collapse into the tissue site 102 so that the
plurality of projections 212 press into the tissue site 102 and
create microstrain, the application of reduced pressure also causes
the tissue site 102 to be pulled or sucked into the plurality of
projections 212. The plurality of channels 237 formed by the
projections 212 allow (1) the reduced pressure to be distributed
across the tissue site 102 and (2) fluid to flow around the
plurality of projections 212.
[0049] Referring now to FIGS. 7A-8B, another illustrative
embodiment of a drape 308 for use in the reduced pressure treatment
system 100 of FIG. 1 is presented. The drape 308 is a multi-layer
drape for positioning over the tissue site 102 and is configured to
(1) provide a sealed space 314 between the drape 308 and the tissue
site 102 and (2) promote granulation at the tissue site 102.
Similar to the drape 108, the drape 308 may include an adhesive
layer for attaching the drape 308 to the tissue site 102 or the
intact portion of the patient's epidermis 132 to create the sealed
space 314. The reduced pressure interface 110 may be connected to
the drape 308 to allow reduced pressure to be applied to the sealed
space 314. The drape 308 includes an aperture 316 that allows
communication between the reduced pressure interface 110 and the
sealed space 314.
[0050] The drape 308 includes a first layer 340 and a second layer
342 connected to the first layer 340 that forms an inner space 344
between the first layer 340 and the second layer 342. The second
layer 342 is capable of forming a plurality of projections 312 in
the presence of a biasing force represented by arrows 346. The
plurality of projections 312 are formed in the presence of the
biasing force by extending from the second layer 342. In one
embodiment, the biasing force is a positive pressure. In this
embodiment, the drape 308 includes one or more positive pressure
interfaces 348, or pressurization ports. The positive pressure
interface 348 is in fluid communication with the inner space 344.
The positive pressure interface 348 may be positioned on or
attached to the first layer 340. The positive pressure interface
348 allows positive pressure from a positive pressure source (not
shown) to be delivered to the inner space 344. In one embodiment,
the plurality of projections 312 are formed when a positive
pressure, p1, within the inner space 344 is greater than a
threshold pressure. In one embodiment, the distance to which the
plurality of projections 312 extend from the second layer 342
depends on the level of the positive pressure, p1, within the inner
space 344 that is beyond the threshold pressure.
[0051] The plurality of projections 312 may be formed by a number
of shapes as previously disclosed with reference to the plurality
of projections 112. In a specific, non-limiting embodiment, the
shape of the plurality of projections 312 when extended from the
second layer 342 will occupy a volume described by cube volumes
where the side of the cube would range between approximately 0.2
millimeters (mm) to 1.5 mm. In one embodiment, the spike shape
would have a base length or diameter of about 0.2 mm and a vertical
height of between 0.4 mm to 0.8 mm. In another embodiment, the cone
shape would have a base diameter of about 0.4 mm and a vertical
height of between 0.4 mm to 1.2 mm. In yet another embodiment, the
dome shape would be a spherical cap or parabolic shape with a base
diameter ranging from about 0.4 mm to 1 mm.
[0052] In one embodiment, the second layer 342 includes a first
plurality of sections 350 having a first thickness, t1, and a
second plurality of sections 352 having a second thickness, t2. The
second thickness, t2, is less than the first thickness, t1. In this
embodiment, the second plurality of sections 352 are configured to
form the plurality of projections 312 in the presence of the
biasing force.
[0053] The first layer 340 and the second layer 342 may be formed
from the same material. For example, the first layer 340 and the
second layer 342 may be formed from silicone or another flexible
biomedical material that can be easily removed from the tissue site
102 even in the presence of granulation formation.
[0054] Referring now specifically to FIGS. 7A and 7B, a dressing
303 that includes the drape 308 and the reduced pressure interface
110 is shown covering the tissue site 102. FIG. 7A illustrates the
drape 308 loosely placed over the tissue site 102 prior to the
application of reduced pressure to the sealed space 314 and prior
to the application of positive pressure to the inner space 344. The
drape 308 extends beyond the perimeter of the tissue site 102 and
contacts the intact portion of the patient's epidermis 132. While
FIG. 7B shows the plurality of projections 312 contacting the
intact portion of the patient's epidermis 132, it should be
appreciated that the plurality of projections 312 may be limited to
an inner portion of the drape 308 and only an outer, smooth portion
of the drape 308 contacts the intact portion of the patient's
epidermis 132. The adhesive layer seals the drape 308 to the intact
portion of the patient's epidermis 132, creating the sealed space
314. FIG. 7B illustrates the drape 308 after reduced pressure has
been applied to the sealed space 314 and after positive pressure
has been applied to the inner space 344 at sufficient levels to
extend the plurality of projections 312. FIG. 7B shows the
plurality of projections 312 pressed against the tissue site 102.
Arrow 334 represents the downward force exerted on the drape 308
when reduced pressure has been applied to the sealed space 114. The
arrows 346 represent the force exerted on the plurality of
projections 312 created by the positive pressure. The reduced
pressure applied to the sealed space 314 not only causes the drape
308 to collapse into the tissue site 102 so that the plurality of
projections 312 press into the tissue site 102 and create
microstrain, the application of reduced pressure also causes the
tissue site 102 to be pulled or sucked into the plurality of
projections 312.
[0055] Referring now to FIGS. 8A and 8B, a detailed view of a
portion the drape 308 is presented. FIG. 8A is a detailed view of
the drape 308 positioned over to the tissue site 102 prior to
reduced pressure being applied. FIG. 8B is a detailed view of the
drape 308 positioned over to the tissue site 102 after reduced
pressure has been applied to the sealed space 314 and after
positive pressure has been applied to the inner space 344 at
sufficient levels to form the plurality of projections 312.
[0056] It should be apparent from the foregoing that an invention
having significant advantages has been provided. While the
invention is shown in only a few of its forms, it is not just
limited but is susceptible to various changes and modifications
without departing from the spirit thereof.
[0057] While a number of discrete embodiments have been described,
aspects of each embodiment may not be specific to only that
embodiment and it is specifically contemplated that features of
embodiments may be combined with features of other embodiments.
* * * * *