U.S. patent application number 16/000383 was filed with the patent office on 2019-08-01 for peel and place dressing for negative-pressure treatment.
The applicant listed for this patent is KCI Licensing, Inc.. Invention is credited to Christopher Brian LOCKE, Timothy Mark ROBINSON.
Application Number | 20190231601 16/000383 |
Document ID | / |
Family ID | 62705768 |
Filed Date | 2019-08-01 |
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United States Patent
Application |
20190231601 |
Kind Code |
A1 |
LOCKE; Christopher Brian ;
et al. |
August 1, 2019 |
PEEL AND PLACE DRESSING FOR NEGATIVE-PRESSURE TREATMENT
Abstract
A dressing for treating a tissue site with negative pressure may
comprise a tissue interface comprising a three-dimensional textile
of polyester fibers and a polymer coating on the polyester fibers.
In some examples, the three-dimensional textile may be a
three-dimensional weave of polyester fibers, and the polymer
coating may be hydrophobic. In more particular embodiments, the
polymer coating may be silicone or polyethylene, for example. The
dressing may additionally include a drape disposed over the tissue
interface and a port fluidly coupled to the tissue interface
through the drape. The tissue interface may be applied over a
tissue site, and therapeutic levels of negative pressure may be
applied to the tissue site through the tissue interface.
Inventors: |
LOCKE; Christopher Brian;
(Bournemouth, GB) ; ROBINSON; Timothy Mark;
(Shillingstone, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KCI Licensing, Inc. |
San Antonio |
TX |
US |
|
|
Family ID: |
62705768 |
Appl. No.: |
16/000383 |
Filed: |
June 5, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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62650572 |
Mar 30, 2018 |
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62633438 |
Feb 21, 2018 |
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62625704 |
Feb 2, 2018 |
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62623325 |
Jan 29, 2018 |
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62616244 |
Jan 11, 2018 |
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62615821 |
Jan 10, 2018 |
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62613494 |
Jan 4, 2018 |
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62592950 |
Nov 30, 2017 |
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62576498 |
Oct 24, 2017 |
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62565754 |
Sep 29, 2017 |
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62516540 |
Jun 7, 2017 |
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62516550 |
Jun 7, 2017 |
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62516566 |
Jun 7, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2013/51139
20130101; A61F 13/00063 20130101; B32B 27/32 20130101; A61F
2013/15406 20130101; A61F 13/0263 20130101; B32B 27/065 20130101;
A61F 2013/00319 20130101; A61F 13/0289 20130101; A61F 2013/51322
20130101; B32B 2307/73 20130101; A61F 13/0216 20130101; A61F
13/0223 20130101; A61L 15/24 20130101; A61M 2205/3344 20130101;
A61F 2013/5127 20130101; A61L 15/52 20130101; A61F 13/0206
20130101; A61M 2207/00 20130101; B29L 2031/753 20130101; A61F
13/0213 20130101; A61L 15/26 20130101; B32B 5/18 20130101; A61M
1/0086 20140204; A61L 2420/00 20130101; A61M 2205/584 20130101;
A61F 13/00059 20130101; A61F 2013/00659 20130101; A61F 13/00068
20130101; A61F 2013/51147 20130101; B32B 3/266 20130101; B29C
65/7808 20130101; A61B 46/20 20160201; B32B 2535/00 20130101; B29C
65/04 20130101; A61F 2013/51372 20130101; A61M 1/0088 20130101 |
International
Class: |
A61F 13/00 20060101
A61F013/00; A61L 15/26 20060101 A61L015/26; A61L 15/52 20060101
A61L015/52; A61B 46/20 20060101 A61B046/20; A61M 1/00 20060101
A61M001/00 |
Claims
1. A dressing for treating a tissue site with negative pressure,
the dressing comprising: a tissue interface comprising a
three-dimensional textile of polyester fibers; and a polymer
coating on the polyester fibers.
2. The dressing of claim 1, wherein the three-dimensional textile
is a three-dimensional weave of polyester fibers.
3. The dressing of claim 1, wherein the polymer is hydrophobic.
4. The dressing of claim 1, wherein the three-dimensional textile
has a weight of about 470 grams per square meter.
5. The dressing of claim 1, wherein the three-dimensional textile
further comprises cotton fibers.
6. The dressing of claim 4, wherein the three-dimensional textile
has a weight of about 650 grams per square meter.
7. The dressing of claim 1, wherein the three-dimensional textile
has a weight of about 380 grams per square meter.
8. The dressing of claim 7, wherein the polyester fibers are
elastic in at least two dimensions.
9. The dressing of claim 7, wherein the polymer coating is
discontinuous.
10. The dressing of claim 8, wherein the polymer is silicone.
11. The dressing of claim 8, wherein the polymer is
polyethylene.
12. The dressing of claim 1, further comprising a sealing layer
adjacent to the tissue interface, the sealing layer having a
plurality of apertures.
13. The dressing of claim 1, wherein the tissue interface further
comprises: a polymer film disposed adjacent to the
three-dimensional textile; and a plurality of fluid restrictions in
the polymer film.
14. The dressing of claim 12, wherein the tissue interface further
comprises: a polymer film disposed adjacent to the sealing layer;
and a plurality of fluid restrictions in the polymer film fluidly
coupled to the plurality of apertures.
15. The dressing of claim 14, wherein the polymer film is
hydrophobic.
16. The dressing of claim 14, wherein the polymer film has a
contact angle with water greater than 90 degrees.
17. The dressing of claim 14, wherein the polymer film is a
polyethylene film having an area density of less than 30 grams per
square meter.
18. The dressing of claim 14, wherein the fluid restrictions
comprise a plurality of slots, each of the slots having a length
less than 4 millimeters.
19. The dressing of claim 14, wherein the fluid restrictions
comprise a plurality of slots, each of the slots having a width
less than 2 millimeters.
20. The dressing of claim 14, wherein the fluid restrictions
comprise a plurality of slots, each of the slots having a length
less than 4 millimeters and a width less than 2 millimeters.
21. The dressing of claim 14, wherein the fluid restrictions
comprise or consist essentially of elastomeric valves in the
polymer film that are normally closed.
22. The dressing of claim 21, wherein the elastomeric valves are
fenestrations.
23. The dressing of claim 21, wherein the elastomeric valves are
slits.
24. The dressing of claim 21, wherein the fluid restrictions
comprise a plurality of slits in the polymer film, each of the
slits having a length less than 4 millimeters.
25. The dressing of claim 12, wherein the sealing layer comprises a
hydrophobic gel.
26. The dressing of claim 25, wherein the hydrophobic gel is a
silicone gel.
27. The dressing of claim 1, further comprising: a drape disposed
over the tissue interface; and a fluid port fluidly coupled to the
tissue interface through the drape.
28. A method of using the dressing of claim 1, the method
comprising: applying the tissue interface over the tissue site; and
applying therapeutic levels of negative pressure to the tissue site
through the tissue interface.
29. (canceled)
30. (canceled)
31. An apparatus for treating a tissue site with negative pressure,
the apparatus comprising: a tissue interface comprising a
three-dimensional textile of polyester fibers; a polymer coating on
the polyester fibers; and a source of negative pressure configured
to be coupled to the tissue interface.
Description
RELATED APPLICATION
[0001] This application claims the benefit, under 35 U.S.C. .sctn.
119(e), of the filing of U.S. Provisional Patent Application Ser.
No. 62/650,572, entitled "ASSEMBLY FEATURES AND METHODS FOR A
PEEL-AND-PLACE DRESSING FOR USE WITH NEGATIVE-PRESSURE TREATMENT,"
filed Mar. 30, 2018; U.S. Provisional Patent Application Ser. No.
62/633,438, entitled "COMPOSITE DRESSINGS FOR IMPROVED GRANULATION
AND REDUCED MACERATION WITH NEGATIVE-PRESSURE TREATMENT," filed
Feb. 21, 2018; U.S. Provisional Patent Application Ser. No.
62/623,325, entitled "METHODS FOR MANUFACTURING AND ASSEMBLING DUAL
MATERIAL TISSUE INTERFACE FOR NEGATIVE-PRESSURE THERAPY," filed
Jan. 29, 2018; U.S. Provisional Patent Application Ser. No.
62/625,704, entitled "CUSTOMIZABLE COMPOSITE DRESSINGS FOR IMPROVED
GRANULATION AND REDUCED MACERATION WITH NEGATIVE-PRESSURE
TREATMENT," filed Feb. 2, 2018; U.S. Provisional Patent Application
Ser. No. 62/616,244, entitled "COMPOSITE DRESSINGS FOR IMPROVED
GRANULATION AND REDUCED MACERATION WITH NEGATIVE-PRESSURE
TREATMENT," filed Jan. 11, 2018; U.S. Provisional Patent
Application Ser. No. 62/615,821, entitled "METHODS FOR
MANUFACTURING AND ASSEMBLING DUAL MATERIAL TISSUE INTERFACE FOR
NEGATIVE-PRESSURE THERAPY," filed Jan. 10, 2018; U.S. Provisional
Patent Application Ser. No. 62/613,494, entitled "PEEL AND PLACE
DRESSING FOR THICK EXUDATE AND INSTILLATION," filed Jan. 4, 2018;
U.S. Provisional Patent Application Ser. No. 62/592,950, entitled
"MULTI-LAYER WOUND FILLER FOR EXTENDED WEAR TIME," filed Nov. 30,
2017; U.S. Provisional Patent Application Ser. No. 62/576,498,
entitled "SYSTEMS, APPARATUSES, AND METHODS FOR NEGATIVE-PRESSURE
TREATMENT WITH REDUCED TISSUE IN-GROWTH," filed Oct. 24, 2017; U.S.
Provisional Patent Application Ser. No. 62/565,754, entitled
"COMPOSITE DRESSINGS FOR IMPROVED GRANULATION AND REDUCED
MACERATION WITH NEGATIVE-PRESSURE TREATMENT," filed Sep. 29, 2017;
U.S. Provisional Patent Application Ser. No. 62/516,540, entitled
"TISSUE CONTACT INTERFACE," filed Jun. 7, 2017; U.S. Provisional
Patent Application Ser. No. 62/516,550, entitled "COMPOSITE
DRESSINGS FOR IMPROVED GRANULATION AND REDUCED MACERATION WITH
NEGATIVE-PRESSURE TREATMENT" filed Jun. 7, 2017; and U.S.
Provisional Patent Application Ser. No. 62/516,566, entitled
"COMPOSITE DRESSINGS FOR IMPROVED GRANULATION AND REDUCED
MACERATION WITH NEGATIVE-PRESSURE TREATMENT" filed Jun. 7, 2017,
each of which is incorporated herein by reference for all
purposes.
TECHNICAL FIELD
[0002] The invention set forth in the appended claims relates
generally to tissue treatment systems and more particularly, but
without limitation, to dressings for tissue treatment and methods
of using the dressings for tissue treatment.
BACKGROUND
[0003] Clinical studies and practice have shown that reducing
pressure in proximity to a tissue site can augment and accelerate
growth of new tissue at the tissue site. The applications of this
phenomenon are numerous, but it has proven particularly
advantageous for treating wounds. Regardless of the etiology of a
wound, whether trauma, surgery, or another cause, proper care of
the wound is important to the outcome. Treatment of wounds or other
tissue with reduced pressure may be commonly referred to as
"negative-pressure therapy," but is also known by other names,
including "negative-pressure wound therapy," "reduced-pressure
therapy," "vacuum therapy," "vacuum-assisted closure," and "topical
negative-pressure," for example. Negative-pressure therapy may
provide a number of benefits, including migration of epithelial and
subcutaneous tissues, improved blood flow, and micro-deformation of
tissue at a wound site. Together, these benefits can increase
development of granulation tissue and reduce healing times.
[0004] There is also widespread acceptance that cleansing a tissue
site can be highly beneficial for new tissue growth. For example, a
wound or a cavity can be washed out with a liquid solution for
therapeutic purposes. These practices are commonly referred to as
"irrigation" and "lavage" respectively. "Instillation" is another
practice that generally refers to a process of slowly introducing
fluid to a tissue site and leaving the fluid for a prescribed
period of time before removing the fluid. For example, instillation
of topical treatment solutions over a wound bed can be combined
with negative-pressure therapy to further promote wound healing by
loosening soluble contaminants in a wound bed and removing
infectious material. As a result, soluble bacterial burden can be
decreased, contaminants removed, and the wound cleansed.
[0005] While the clinical benefits of negative-pressure therapy
and/or instillation therapy are widely known, improvements to
therapy systems, components, and processes may benefit healthcare
providers and patients.
BRIEF SUMMARY
[0006] New and useful systems, apparatuses, and methods for
treating tissue in a negative-pressure therapy environment are set
forth in the appended claims. Illustrative embodiments are also
provided to enable a person skilled in the art to make and use the
claimed subject matter.
[0007] For example, in some embodiments, a dressing for treating
tissue may be a composite of dressing layers, including a manifold
comprising or consisting essentially of a three-dimensional
textile. Suitable textiles may include a fabric of polyester and
cotton or a polyester spacer fabric. In some examples, the fabric
may have a close-woven layer of polyester on one or more opposing
faces of the manifold. The close-woven layer of polyester may be
configured to face a tissue site in use. In some embodiments, the
manifold may additionally or alternatively include a material that
can be stretched linearly in at least one dimension, which can
allow the dressing to deform into deep wounds. Silicone or other
suitable hydrophobic polymer may be coated on the three-dimensional
textile in some embodiments, which can provide additional
advantages without impeding the stretch deformation characteristics
of the dressing.
[0008] More generally, a dressing for treating a tissue site with
negative pressure may comprise a tissue interface comprising a
three-dimensional textile of polyester fibers and a polymer coating
on the polyester fibers. In some examples, the three-dimensional
textile may be a three-dimensional weave of polyester fibers, and
the polymer coating may be hydrophobic. In more particular
embodiments, the polymer coating may be silicone or polyethylene,
for example.
[0009] The dressing may additionally include a drape disposed over
the tissue interface and a port fluidly coupled to the tissue
interface through the drape.
[0010] The tissue interface may be applied over a tissue site, and
therapeutic levels of negative pressure may be applied to the
tissue site through the tissue interface.
[0011] Objectives, advantages, and a preferred mode of making and
using the claimed subject matter may be understood best by
reference to the accompanying drawings in conjunction with the
following detailed description of illustrative embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a functional block diagram of an example
embodiment of a therapy system that can provide tissue treatment in
accordance with this specification;
[0013] FIG. 2 is an assembly view of an example of a dressing,
illustrating additional details that may be associated with some
example embodiments of the therapy system of FIG. 1;
[0014] FIG. 3 is a schematic view of an example configuration of
fluid restrictions in a layer that may be associated with some
embodiments of the dressing of FIG. 2;
[0015] FIG. 4 is an assembly view of another example of a dressing,
illustrating additional details that may be associated with some
example embodiment of the therapy system of FIG. 1;
[0016] FIG. 5 is a schematic view of an example configuration of
apertures in a layer that may be associated with some embodiments
of the dressing of FIG. 4;
[0017] FIG. 6 is a schematic view of the example layer of FIG. 5
overlaid on the example layer of FIG. 3;
[0018] FIG. 7 is a schematic view of another example of a layer
that may be associated with some embodiments of a dressing;
[0019] FIG. 8 is a perspective view of another example
configuration of layers that may be associated with the dressing of
FIG. 2; and
[0020] FIG. 9 is a partial cutaway view of another example
configuration of layers that may be associated with the dressing of
FIG. 2.
DESCRIPTION OF EXAMPLE EMBODIMENTS
[0021] The following description of example embodiments provides
information that enables a person skilled in the art to make and
use the subject matter set forth in the appended claims, but it may
omit certain details already well-known in the art. The following
detailed description is, therefore, to be taken as illustrative and
not limiting.
[0022] The example embodiments may also be described herein with
reference to spatial relationships between various elements or to
the spatial orientation of various elements depicted in the
attached drawings. In general, such relationships or orientation
assume a frame of reference consistent with or relative to a
patient in a position to receive treatment. However, as should be
recognized by those skilled in the art, this frame of reference is
merely a descriptive expedient rather than a strict
prescription.
[0023] FIG. 1 is a simplified functional block diagram of an
example embodiment of a therapy system 100 that can provide
negative-pressure therapy with instillation of topical treatment
solutions to a tissue site in accordance with this
specification.
[0024] The term "tissue site" in this context broadly refers to a
wound, defect, or other treatment target located on or within
tissue, including, but not limited to, bone tissue, adipose tissue,
muscle tissue, neural tissue, dermal tissue, vascular tissue,
connective tissue, cartilage, tendons, or ligaments. A wound may
include chronic, acute, traumatic, subacute, and dehisced wounds,
partial-thickness burns, ulcers (such as diabetic, pressure, or
venous insufficiency ulcers), flaps, and grafts, for example. The
term "tissue site" may also refer to areas of any tissue that are
not necessarily wounded or defective, but are instead areas in
which it may be desirable to add or promote the growth of
additional tissue. For example, negative pressure may be applied to
a tissue site to grow additional tissue that may be harvested and
transplanted.
[0025] The therapy system 100 may include a source or supply of
negative pressure, such as a negative-pressure source 105, and one
or more distribution components. A distribution component is
preferably detachable and may be disposable, reusable, or
recyclable. A dressing, such as a dressing 110, and a fluid
container, such as a container 115, are examples of distribution
components that may be associated with some examples of the therapy
system 100. As illustrated in the example of FIG. 1, the dressing
110 may comprise or consist essentially of a tissue interface 120,
a cover 125, or both in some embodiments.
[0026] A fluid conductor is another illustrative example of a
distribution component. A "fluid conductor," in this context,
broadly includes a tube, pipe, hose, conduit, or other structure
with one or more lumina or open pathways adapted to convey a fluid
between two ends. Typically, a tube is an elongated, cylindrical
structure with some flexibility, but the geometry and rigidity may
vary. Moreover, some fluid conductors may be molded into or
otherwise integrally combined with other components. Distribution
components may also include or comprise interfaces or fluid ports
to facilitate coupling and de-coupling other components. In some
embodiments, for example, a dressing interface may facilitate
coupling a fluid conductor to the dressing 110. For example, such a
dressing interface may be a SENSAT.R.A.C..TM. Pad available from
Kinetic Concepts, Inc. of San Antonio, Tex.
[0027] The therapy system 100 may also include a regulator or
controller, such as a controller 130. Additionally, the therapy
system 100 may include sensors to measure operating parameters and
provide feedback signals to the controller 130 indicative of the
operating parameters. As illustrated in FIG. 1, for example, the
therapy system 100 may include a first sensor 135 and a second
sensor 140 coupled to the controller 130.
[0028] The therapy system 100 may also include a source of
instillation solution. For example, a solution source 145 may be
fluidly coupled to the dressing 110, as illustrated in the example
embodiment of FIG. 1. The solution source 145 may be fluidly
coupled to a positive-pressure source such as a positive-pressure
source 150, a negative-pressure source such as the
negative-pressure source 105, or both in some embodiments. A
regulator, such as an instillation regulator 155, may also be
fluidly coupled to the solution source 145 and the dressing 110 to
ensure proper dosage of instillation solution (e.g. saline) to a
tissue site. For example, the instillation regulator 155 may
comprise a piston that can be pneumatically actuated by the
negative-pressure source 105 to draw instillation solution from the
solution source during a negative-pressure interval and to instill
the solution to a dressing during a venting interval. Additionally
or alternatively, the controller 130 may be coupled to the
negative-pressure source 105, the positive-pressure source 150, or
both, to control dosage of instillation solution to a tissue site.
In some embodiments, the instillation regulator 155 may also be
fluidly coupled to the negative-pressure source 105 through the
dressing 110, as illustrated in the example of FIG. 1.
[0029] Some components of the therapy system 100 may be housed
within or used in conjunction with other components, such as
sensors, processing units, alarm indicators, memory, databases,
software, display devices, or user interfaces that further
facilitate therapy. For example, in some embodiments, the
negative-pressure source 105 may be combined with the controller
130, the solution source 145, and other components into a therapy
unit.
[0030] In general, components of the therapy system 100 may be
coupled directly or indirectly. For example, the negative-pressure
source 105 may be directly coupled to the container 115 and may be
indirectly coupled to the dressing 110 through the container 115.
Coupling may include fluid, mechanical, thermal, electrical, or
chemical coupling (such as a chemical bond), or some combination of
coupling in some contexts. For example, the negative-pressure
source 105 may be electrically coupled to the controller 130 and
may be fluidly coupled to one or more distribution components to
provide a fluid path to a tissue site. In some embodiments,
components may also be coupled by virtue of physical proximity,
being integral to a single structure, or being formed from the same
piece of material.
[0031] A negative-pressure supply, such as the negative-pressure
source 105, may be a reservoir of air at a negative pressure or may
be a manual or electrically-powered device, such as a vacuum pump,
a suction pump, a wall suction port available at many healthcare
facilities, or a micro-pump, for example. "Negative pressure"
generally refers to a pressure less than a local ambient pressure,
such as the ambient pressure in a local environment external to a
sealed therapeutic environment. In many cases, the local ambient
pressure may also be the atmospheric pressure at which a tissue
site is located. Alternatively, the pressure may be less than a
hydrostatic pressure associated with tissue at the tissue site.
Unless otherwise indicated, values of pressure stated herein are
gauge pressures. References to increases in negative pressure
typically refer to a decrease in absolute pressure, while decreases
in negative pressure typically refer to an increase in absolute
pressure. While the amount and nature of negative pressure provided
by the negative-pressure source 105 may vary according to
therapeutic requirements, the pressure is generally a low vacuum,
also commonly referred to as a rough vacuum, between -5 mm Hg (-667
Pa) and -500 mm Hg (-66.7 kPa). Common therapeutic ranges are
between -50 mm Hg (-6.7 kPa) and -300 mm Hg (-39.9 kPa).
[0032] The container 115 is representative of a container,
canister, pouch, or other storage component, which can be used to
manage exudates and other fluids withdrawn from a tissue site. In
many environments, a rigid container may be preferred or required
for collecting, storing, and disposing of fluids. In other
environments, fluids may be properly disposed of without rigid
container storage, and a re-usable container could reduce waste and
costs associated with negative-pressure therapy.
[0033] A controller, such as the controller 130, may be a
microprocessor or computer programmed to operate one or more
components of the therapy system 100, such as the negative-pressure
source 105. In some embodiments, for example, the controller 130
may be a microcontroller, which generally comprises an integrated
circuit containing a processor core and a memory programmed to
directly or indirectly control one or more operating parameters of
the therapy system 100. Operating parameters may include the power
applied to the negative-pressure source 105, the pressure generated
by the negative-pressure source 105, or the pressure distributed to
the tissue interface 120, for example. The controller 130 is also
preferably configured to receive one or more input signals, such as
a feedback signal, and programmed to modify one or more operating
parameters based on the input signals.
[0034] Sensors, such as the first sensor 135 and the second sensor
140, are generally known in the art as any apparatus operable to
detect or measure a physical phenomenon or property, and generally
provide a signal indicative of the phenomenon or property that is
detected or measured. For example, the first sensor 135 and the
second sensor 140 may be configured to measure one or more
operating parameters of the therapy system 100. In some
embodiments, the first sensor 135 may be a transducer configured to
measure pressure in a pneumatic pathway and convert the measurement
to a signal indicative of the pressure measured. In some
embodiments, for example, the first sensor 135 may be a
piezo-resistive strain gauge. The second sensor 140 may optionally
measure operating parameters of the negative-pressure source 105,
such as a voltage or current, in some embodiments. Preferably, the
signals from the first sensor 135 and the second sensor 140 are
suitable as an input signal to the controller 130, but some signal
conditioning may be appropriate in some embodiments. For example,
the signal may need to be filtered or amplified before it can be
processed by the controller 130. Typically, the signal is an
electrical signal, but may be represented in other forms, such as
an optical signal.
[0035] The tissue interface 120 can be generally adapted to
partially or fully contact a tissue site. The tissue interface 120
may take many forms, and may have many sizes, shapes, or
thicknesses, depending on a variety of factors, such as the type of
treatment being implemented or the nature and size of a tissue
site. For example, the size and shape of the tissue interface 120
may be adapted to the contours of deep and irregular shaped tissue
sites. Any or all of the surfaces of the tissue interface 120 may
have an uneven, coarse, or jagged profile.
[0036] In some embodiments, the tissue interface 120 may comprise
or consist essentially of a manifold. A manifold in this context
may comprise or consist essentially of a means for collecting or
distributing fluid across the tissue interface 120 under pressure.
For example, a manifold may be adapted to receive negative pressure
from a source and distribute negative pressure through multiple
apertures across the tissue interface 120, which may have the
effect of collecting fluid from across a tissue site and drawing
the fluid toward the source. In some embodiments, the fluid path
may be reversed or a secondary fluid path may be provided to
facilitate delivering fluid, such as fluid from a source of
instillation solution, across a tissue site.
[0037] In some embodiments, the cover 125 may provide a bacterial
barrier and protection from physical trauma. The cover 125 may also
be constructed from a material that can reduce evaporative losses
and provide a fluid seal between two components or two
environments, such as between a therapeutic environment and a local
external environment. The cover 125 may comprise or consist of, for
example, an elastomeric film or membrane that can provide a seal
adequate to maintain a negative pressure at a tissue site for a
given negative-pressure source. The cover 125 may have a high
moisture-vapor transmission rate (MVTR) in some applications. For
example, the MVTR may be at least 250 grams per square meter per
twenty-four hours in some embodiments, measured using an upright
cup technique according to ASTM E96/E96M Upright Cup Method at
38.degree. C. and 10% relative humidity (RH). In some embodiments,
an MVTR up to 5,000 grams per square meter per twenty-four hours
may provide effective breathability and mechanical properties.
[0038] In some example embodiments, the cover 125 may be a polymer
drape, such as a polyurethane film, that is permeable to water
vapor but impermeable to liquid. Such drapes typically have a
thickness in the range of 25-50 microns. For permeable materials,
the permeability generally should be low enough that a desired
negative pressure may be maintained. The cover 125 may comprise,
for example, one or more of the following materials: polyurethane
(PU), such as hydrophilic polyurethane; cellulosics; hydrophilic
polyamides; polyvinyl alcohol; polyvinyl pyrrolidone; hydrophilic
acrylics; silicones, such as hydrophilic silicone elastomers;
natural rubbers; polyisoprene; styrene butadiene rubber;
chloroprene rubber; polybutadiene; nitrile rubber; butyl rubber;
ethylene propylene rubber; ethylene propylene diene monomer;
chlorosulfonated polyethylene; polysulfide rubber; ethylene vinyl
acetate (EVA); co-polyester; and polyether block polymide
copolymers. Such materials are commercially available as, for
example, Tegaderm.RTM. drape, commercially available from 3M
Company, Minneapolis Minn.; polyurethane (PU) drape, commercially
available from Avery Dennison Corporation, Pasadena, Calif.;
polyether block polyamide copolymer (PEBAX), for example, from
Arkema S.A., Colombes, France; and Inspire 2301 and Inpsire 2327
polyurethane films, commercially available from Expopack Advanced
Coatings, Wrexham, United Kingdom. In some embodiments, the cover
125 may comprise INSPIRE 2301 having an MVTR (upright cup
technique) of 2600 g/m.sup.2/24 hours and a thickness of about 30
microns.
[0039] An attachment device may be used to attach the cover 125 to
an attachment surface, such as undamaged epidermis, a gasket, or
another cover. The attachment device may take many forms. For
example, an attachment device may be a medically-acceptable,
pressure-sensitive adhesive configured to bond the cover 125 to
epidermis around a tissue site. In some embodiments, for example,
some or all of the cover 125 may be coated with an adhesive, such
as an acrylic adhesive, which may have a coating weight of about
25-65 grams per square meter (g.s.m.). Thicker adhesives, or
combinations of adhesives, may be applied in some embodiments to
improve the seal and reduce leaks. Other example embodiments of an
attachment device may include a double-sided tape, paste,
hydrocolloid, hydrogel, silicone gel, or organogel.
[0040] The solution source 145 may also be representative of a
container, canister, pouch, bag, or other storage component, which
can provide a solution for instillation therapy. Compositions of
solutions may vary according to a prescribed therapy, but examples
of solutions that may be suitable for some prescriptions include
hypochlorite-based solutions, silver nitrate (0.5%), sulfur-based
solutions, biguanides, cationic solutions, and isotonic
solutions.
[0041] In operation, the tissue interface 120 may be placed within,
over, on, or otherwise proximate to a tissue site. If the tissue
site is a wound, for example, the tissue interface 120 may
partially or completely fill the wound, or it may be placed over
the wound. The cover 125 may be placed over the tissue interface
120 and sealed to an attachment surface near a tissue site. For
example, the cover 125 may be sealed to undamaged epidermis
peripheral to a tissue site. Thus, the dressing 110 can provide a
sealed therapeutic environment proximate to a tissue site,
substantially isolated from the external environment, and the
negative-pressure source 105 can reduce pressure in the sealed
therapeutic environment.
[0042] The fluid mechanics of using a negative-pressure source to
reduce pressure in another component or location, such as within a
sealed therapeutic environment, can be mathematically complex.
However, the basic principles of fluid mechanics applicable to
negative-pressure therapy and instillation are generally well-known
to those skilled in the art, and the process of reducing pressure
may be described illustratively herein as "delivering,"
"distributing," or "generating" negative pressure, for example.
[0043] In general, exudate and other fluid flow toward lower
pressure along a fluid path. Thus, the term "downstream" typically
implies something in a fluid path relatively closer to a source of
negative pressure or further away from a source of positive
pressure. Conversely, the term "upstream" implies something
relatively further away from a source of negative pressure or
closer to a source of positive pressure. Similarly, it may be
convenient to describe certain features in terms of fluid "inlet"
or "outlet" in such a frame of reference. This orientation is
generally presumed for purposes of describing various features and
components herein. However, the fluid path may also be reversed in
some applications, such as by substituting a positive-pressure
source for a negative-pressure source, and this descriptive
convention should not be construed as a limiting convention.
[0044] Negative pressure applied across the tissue site through the
tissue interface 120 in the sealed therapeutic environment can
induce macro-strain and micro-strain in the tissue site. Negative
pressure can also remove exudate and other fluid from a tissue
site, which can be collected in container 115.
[0045] In some embodiments, the controller 130 may receive and
process data from one or more sensors, such as the first sensor
135. The controller 130 may also control the operation of one or
more components of the therapy system 100 to manage the pressure
delivered to the tissue interface 120. In some embodiments,
controller 130 may include an input for receiving a desired target
pressure and may be programmed for processing data relating to the
setting and inputting of the target pressure to be applied to the
tissue interface 120. In some example embodiments, the target
pressure may be a fixed pressure value set by an operator as the
target negative pressure desired for therapy at a tissue site and
then provided as input to the controller 130. The target pressure
may vary from tissue site to tissue site based on the type of
tissue forming a tissue site, the type of injury or wound (if any),
the medical condition of the patient, and the preference of the
attending physician. After selecting a desired target pressure, the
controller 130 can operate the negative-pressure source 105 in one
or more control modes based on the target pressure and may receive
feedback from one or more sensors to maintain the target pressure
at the tissue interface 120.
[0046] FIG. 2 is an assembly view of an example of the dressing 110
of FIG. 1, illustrating additional details that may be associated
with some embodiments in which the tissue interface 120 comprises
more than one layer. In the example of FIG. 2, the tissue interface
120 comprises a first layer 205 and a second layer 210. In some
embodiments, the first layer 205 may be disposed adjacent to the
second layer 210. For example, the first layer 205 and the second
layer 210 may be stacked so that the first layer 205 is in contact
with the second layer 210. The first layer 205 may also be bonded
to the second layer 210 in some embodiments. In some embodiments,
the second layer 210 may be coextensive with a face of the first
layer 205.
[0047] The first layer 205 generally comprises or consists
essentially of a manifold or a manifold layer, which provides a
means for collecting or distributing fluid across the tissue
interface 120 under pressure. For example, the first layer 205 may
be adapted to receive negative pressure from a source and
distribute negative pressure through multiple apertures across the
tissue interface 120, which may have the effect of collecting fluid
from across a tissue site and drawing the fluid toward the source.
In some embodiments, the fluid path may be reversed or a secondary
fluid path may be provided to facilitate delivering fluid, such as
from a source of instillation solution, across the tissue interface
120.
[0048] In some illustrative embodiments, the pathways of the first
layer 205 may be interconnected to improve distribution or
collection of fluids. In some illustrative embodiments, the first
layer 205 may comprise or consist essentially of a porous material
having interconnected fluid pathways. Examples of suitable porous
material that comprise or can be adapted to form interconnected
fluid pathways (e.g., channels) may include cellular foam,
including open-cell foam such as reticulated foam; porous tissue
collections; and other porous material such as gauze or felted mat
that generally include pores, edges, and/or walls. Liquids, gels,
and other foams may also include or be cured to include apertures
and fluid pathways. In some embodiments, the first layer 205 may
additionally or alternatively comprise projections that form
interconnected fluid pathways. For example, the first layer 205 may
be molded to provide surface projections that define interconnected
fluid pathways.
[0049] In some embodiments, the first layer 205 may comprise or
consist essentially of a reticulated foam having pore sizes and
free volume that may vary according to needs of a prescribed
therapy. For example, a reticulated foam having a free volume of at
least 90% may be suitable for many therapy applications, and a foam
having an average pore size in a range of 400-600 microns may be
particularly suitable for some types of therapy. The tensile
strength of the first layer 205 may also vary according to needs of
a prescribed therapy. For example, the tensile strength of a foam
may be increased for instillation of topical treatment solutions.
The 25% compression load deflection of the first layer 205 may be
at least 0.35 pounds per square inch, and the 65% compression load
deflection may be at least 0.43 pounds per square inch. In some
embodiments, the tensile strength of the first layer 205 may be at
least 10 pounds per square inch. The first layer 205 may have a
tear strength of at least 2.5 pounds per inch. In some embodiments,
the first layer 205 may be a foam comprised of polyols such as
polyester or polyether, isocyanate such as toluene diisocyanate,
and polymerization modifiers such as amines and tin compounds. In
some examples, the first layer 205 may be a reticulated
polyurethane foam such as used in GRANUFOAM.TM. dressing or V.A.C.
VERAFLO.TM. dressing, both available from KCI of San Antonio,
Tex.
[0050] Other suitable materials for the first layer 205 may include
non-woven fabrics (Libeltex, Freudenberg), three-dimensional (3D)
polymeric structures (molded polymers, embossed and formed films,
and fusion bonded films [Supracore]), and mesh, for example.
[0051] In some examples, the first layer 205 may include a 3D
textile, such as various textiles commercially available from
Baltex, Muller, and Heathcoates. A 3D textile of polyester fibers
may be particularly advantageous for some embodiments. For example,
the first layer 205 may comprise or consist essentially of a
three-dimensional weave of polyester fibers. In some embodiments,
the fibers may be elastic in at least two dimensions. A
puncture-resistant fabric of polyester and cotton fibers having a
weight of about 650 grams per square meter and a thickness of about
1-2 millimeters may be particularly advantageous for some
embodiments. Such a puncture-resistant fabric may have a warp
tensile strength of about 330-350 kilograms and a weft tensile
strength of about 270-280 kilograms in some embodiments, based on a
50 millimeter sample tested according to BS4650. Another
particularly suitable material may be a polyester spacer fabric
having a weight of about 470 grams per square meter, which may have
a thickness of about 4-5 millimeters in some embodiments. Such a
spacer fabric may have a compression strength of about 20-25
kilopascals (at 40% compression), as measured according to ISO
3386-1. Additionally or alternatively, the first layer 205 may
comprise or consist of a material having substantial linear stretch
properties, such as a polyester spacer fabric having 2-way stretch
and a weight of about 380 grams per square meter. A suitable spacer
fabric may have a thickness of about 3-4 millimeters, and may have
a warp and weft tensile strength of about 30-40 kilograms in some
embodiments, as measured according to BS4650 on a 50 millimeter
sample. The fabric may have a close-woven layer of polyester on one
or more opposing faces in some examples. For example, a suitably
tight weave may leave a space or pore between the warp and weft
fabrics having a width less than 1 millimeter, and less than 0.5
millimeters in some examples. In some embodiments, a woven layer
may be advantageously disposed on a first layer 205 to face a
tissue site.
[0052] The first layer 205 generally has a first planar surface and
a second planar surface opposite the first planar surface. The
thickness of the first layer 205 between the first planar surface
and the second planar surface may also vary according to needs of a
prescribed therapy. For example, the thickness of the first layer
205 may be decreased to relieve stress on other layers and to
reduce tension on peripheral tissue. The thickness of the first
layer 205 can also affect the conformability of the first layer
205. In some embodiments, a suitable foam may have a thickness in a
range of about 5 millimeters to 10 millimeters. Fabrics, including
suitable 3D textiles and spacer fabrics, may have a thickness in a
range of about 2 millimeters to about 8 millimeters.
[0053] The second layer 210 may comprise or consist essentially of
a means for controlling or managing fluid flow. In some
embodiments, the second layer 210 may comprise or consist
essentially of a liquid-impermeable, elastomeric material. For
example, the second layer 210 may comprise or consist essentially
of a polymer film. The second layer 210 may also have a smooth or
matte surface texture in some embodiments. A glossy or shiny finish
better or equal to a grade B3 according to the SPI (Society of the
Plastics Industry) standards may be particularly advantageous for
some applications. In some embodiments, variations in surface
height may be limited to acceptable tolerances. For example, the
surface of the second layer 210 may have a substantially flat
surface, with height variations limited to 0.2 millimeters over a
centimeter.
[0054] In some embodiments, the second layer 210 may be
hydrophobic. The hydrophobicity of the second layer 210 may vary,
but may have a contact angle with water of at least ninety degrees
in some embodiments. In some embodiments the second layer 210 may
have a contact angle with water of no more than 150 degrees. For
example, in some embodiments, the contact angle of the second layer
210 may be in a range of at least 90 degrees to about 120 degrees,
or in a range of at least 120 degrees to 150 degrees. Water contact
angles can be measured using any standard apparatus. Although
manual goniometers can be used to visually approximate contact
angles, contact angle measuring instruments can often include an
integrated system involving a level stage, liquid dropper such as a
syringe, camera, and software designed to calculate contact angles
more accurately and precisely, among other things. Non-limiting
examples of such integrated systems may include the FT.ANG.125,
FT.ANG.200, FT.ANG.2000, and FT.ANG.4000 systems, all commercially
available from First Ten Angstroms, Inc., of Portsmouth, Va., and
the DTA25, DTA30, and DTA100 systems, all commercially available
from Kruss GmbH of Hamburg, Germany. Unless otherwise specified,
water contact angles herein are measured using deionized and
distilled water on a level sample surface for a sessile drop added
from a height of no more than 5 cm in air at 20-25.degree. C. and
20-50% relative humidity. Contact angles reported herein represent
averages of 5-9 measured values, discarding both the highest and
lowest measured values. The hydrophobicity of the second layer 210
may be further enhanced with a hydrophobic coating of other
materials, such as silicones and fluorocarbons, either as coated
from a liquid, or plasma coated.
[0055] The second layer 210 may also be suitable for welding to
other layers, including the first layer 205. For example, the
second layer 210 may be adapted for welding to polyurethane foams
using heat, radio frequency (RF) welding, or other methods to
generate heat such as ultrasonic welding. RF welding may be
particularly suitable for more polar materials, such as
polyurethane, polyamides, polyesters and acrylates. Sacrificial
polar interfaces may be used to facilitate RF welding of less polar
film materials, such as polyethylene.
[0056] The area density of the second layer 210 may vary according
to a prescribed therapy or application. In some embodiments, an
area density of less than 40 grams per square meter may be
suitable, and an area density of about 20-30 grams per square meter
may be particularly advantageous for some applications.
[0057] In some embodiments, for example, the second layer 210 may
comprise or consist essentially of a hydrophobic polymer, such as a
polyethylene film. The simple and inert structure of polyethylene
can provide a surface that interacts little, if any, with
biological tissues and fluids, providing a surface that may
encourage the free flow of liquids and low adherence, which can be
particularly advantageous for many applications. Other suitable
polymeric films include polyurethanes, acrylics, polyolefin (such
as cyclic olefin copolymers), polyacetates, polyamides, polyesters,
copolyesters, PEBAX block copolymers, thermoplastic elastomers,
thermoplastic vulcanizates, polyethers, polyvinyl alcohols,
polypropylene, polymethylpentene, polycarbonate, styreneics,
silicones, fluoropolymers, and acetates. A thickness between 20
microns and 100 microns may be suitable for many applications.
Films may be clear, colored, or printed. More polar films suitable
for laminating to a polyethylene film include polyamide,
copolyesters, ionomers, and acrylics. To aid in the bond between a
polyethylene and polar film, tie layers may be used, such as
ethylene vinyl acetate, or modified polyurethanes. An ethyl methyl
acrylate (EMA) film may also have suitable hydrophobic and welding
properties for some configurations.
[0058] As illustrated in the example of FIG. 2, the second layer
210 may have one or more fluid restrictions 220, which can be
distributed uniformly or randomly across the second layer 210. The
fluid restrictions 220 may be bi-directional and
pressure-responsive. For example, each of the fluid restrictions
220 generally may comprise or consist essentially of an elastic
passage that is normally unstrained to substantially reduce liquid
flow, and can expand or open in response to a pressure gradient. In
some embodiments, the fluid restrictions 220 may comprise or
consist essentially of perforations in the second layer 210.
Perforations may be formed by removing material from the second
layer 210. For example, perforations may be formed by cutting
through the second layer 210, which may also deform the edges of
the perforations in some embodiments. In the absence of a pressure
gradient across the perforations, the passages may be sufficiently
small to form a seal or fluid restriction, which can substantially
reduce or prevent liquid flow. Additionally or alternatively, one
or more of the fluid restrictions 220 may be an elastomeric valve
that is normally closed when unstrained to substantially prevent
liquid flow, and can open in response to a pressure gradient. A
fenestration in the second layer 210 may be a suitable valve for
some applications. Fenestrations may also be formed by removing
material from the second layer 210, but the amount of material
removed and the resulting dimensions of the fenestrations may be up
to an order of magnitude less than perforations, and may not deform
the edges.
[0059] For example, some embodiments of the fluid restrictions 220
may comprise or consist essentially of one or more slits, slots or
combinations of slits and slots in the second layer 210. In some
examples, the fluid restrictions 220 may comprise or consist of
linear slots having a length less than 4 millimeters and a width
less than 1 millimeter. The length may be at least 2 millimeters,
and the width may be at least 0.4 millimeters in some embodiments.
A length of about 3 millimeters and a width of about 0.8
millimeters may be particularly suitable for many applications, and
a tolerance of about 0.1 millimeter may also be acceptable. Such
dimensions and tolerances may be achieved with a laser cutter, for
example. Slots of such configurations may function as imperfect
valves that substantially reduce liquid flow in a normally closed
or resting state. For example, such slots may form a flow
restriction without being completely closed or sealed. The slots
can expand or open wider in response to a pressure gradient to
allow increased liquid flow.
[0060] In the example of FIG. 2, the dressing 110 may further
include an attachment device, such as an adhesive 240. The adhesive
240 may be, for example, a medically-acceptable, pressure-sensitive
adhesive that extends about a periphery, a portion, or an entire
surface of the cover 125. In some embodiments, for example, the
adhesive 240 may be an acrylic adhesive having a coating weight
between 25-65 grams per square meter (g.s.m.). Thicker adhesives,
or combinations of adhesives, may be applied in some embodiments to
improve the seal and reduce leaks. In some embodiments, such a
layer of the adhesive 240 may be continuous or discontinuous.
Discontinuities in the adhesive 240 may be provided by apertures or
holes (not shown) in the adhesive 240. The apertures or holes in
the adhesive 240 may be formed after application of the adhesive
240 or by coating the adhesive 240 in patterns on a carrier layer,
such as, for example, a side of the cover 125. Apertures or holes
in the adhesive 240 may also be sized to enhance the MVTR of the
dressing 110 in some example embodiments.
[0061] As illustrated in the example of FIG. 2, in some
embodiments, the dressing 110 may include a release liner 245 to
protect the adhesive 240 prior to use. The release liner 245 may
also provide stiffness to assist with, for example, deployment of
the dressing 110. The release liner 245 may be, for example, a
casting paper, a film, or polyethylene. Further, in some
embodiments, the release liner 245 may be a polyester material such
as polyethylene terephthalate (PET), or similar polar
semi-crystalline polymer. The use of a polar semi-crystalline
polymer for the release liner 245 may substantially preclude
wrinkling or other deformation of the dressing 110. For example,
the polar semi-crystalline polymer may be highly orientated and
resistant to softening, swelling, or other deformation that may
occur when brought into contact with components of the dressing
110, or when subjected to temperature or environmental variations,
or sterilization. Further, a release agent may be disposed on a
side of the release liner 245 that is configured to contact the
second layer 210. For example, the release agent may be a silicone
coating and may have a release factor suitable to facilitate
removal of the release liner 245 by hand and without damaging or
deforming the dressing 110. In some embodiments, the release agent
may be a fluorocarbon or a fluorosilicone, for example. In other
embodiments, the release liner 245 may be uncoated or otherwise
used without a release agent.
[0062] FIG. 2 also illustrates one example of a fluid conductor 250
and a dressing interface 255. As shown in the example of FIG. 2,
the fluid conductor 250 may be a flexible tube, which can be
fluidly coupled on one end to the dressing interface 255. The
dressing interface 255 may be an elbow connector, as shown in the
example of FIG. 2, which can be placed over an aperture 260 in the
cover 125 to provide a fluid path between the fluid conductor 250
and the tissue interface 120.
[0063] FIG. 3 is a schematic view of an example of the second layer
210, illustrating additional details that may be associated with
some embodiments. As illustrated in the example of FIG. 3, the
fluid restrictions 220 may each consist essentially of one or more
linear slots having a length L. A length of about 3 millimeters may
be particularly suitable for some embodiments. FIG. 3 additionally
illustrates an example of a uniform distribution pattern of the
fluid restrictions 220. In FIG. 3, the fluid restrictions 220 are
substantially coextensive with the second layer 210, and are
distributed across the second layer 210 in a grid of parallel rows
and columns, in which the slots are also mutually parallel to each
other. In some embodiments, the rows may be spaced a distance D1. A
distance of about 3 millimeters on center may be suitable for some
embodiments. The fluid restrictions 220 within each of the rows may
be spaced a distance D2, which may be about 3 millimeters on center
in some examples. The fluid restrictions 220 in adjacent rows may
be aligned or offset in some embodiments. For example, adjacent
rows may be offset, as illustrated in FIG. 3, so that the fluid
restrictions 220 are aligned in alternating rows and separated by a
distance D3, which may be about 6 millimeters in some embodiments.
The spacing of the fluid restrictions 220 may vary in some
embodiments to increase the density of the fluid restrictions 220
according to therapeutic requirements.
[0064] One or more of the components of the dressing 110 may
additionally be treated with an antimicrobial agent in some
embodiments. For example, the first layer 205 may be a foam, mesh,
or non-woven coated with an antimicrobial agent. In some
embodiments, the first layer may comprise antimicrobial elements,
such as fibers coated with an antimicrobial agent. Additionally or
alternatively, some embodiments of the second layer 210 may be a
polymer coated or mixed with an antimicrobial agent. In other
examples, the fluid conductor 250 may additionally or alternatively
be treated with one or more antimicrobial agents. Suitable
antimicrobial agents may include, for example, metallic silver,
PHMB, iodine or its complexes and mixes such as povidone iodine,
copper metal compounds, chlorhexidine, or some combination of these
materials.
[0065] Additionally or alternatively, one or more of the components
may be coated with a mixture that may include citric acid and
collagen, which can reduce bio-films and infections. For example,
the first layer 205 may be a foam coated with such a mixture.
[0066] Individual components of the dressing 110 may be bonded or
otherwise secured to one another with a solvent or non-solvent
adhesive, or with thermal welding, for example, without adversely
affecting fluid management.
[0067] The cover 125, the first layer 205, and the second layer
210, or various combinations may be assembled before application or
in situ. For example, the cover 125 may be laminated to the first
layer 205, and the second layer 210 may be laminated to the first
layer 205 opposite the cover 125 in some embodiments. The second
layer 210 may provide a smooth surface opposite the first layer
205. In some embodiments, one or more layers of the tissue
interface 120 may be coextensive. For example, the second layer 210
may be cut flush with the edge of the first layer 205, exposing the
edge of the first layer 205, as illustrated in the embodiment of
FIG. 2. In other embodiments, the second layer 210 may overlap the
edge of the first layer 205. In some embodiments, the dressing 110
may be provided as a single, composite dressing. For example, the
second layer 210 may be coupled to the cover 125 to enclose the
first layer 205, wherein the second layer 210 is configured to face
a tissue site.
[0068] In use, the release liner 245 (if included) may be removed
to expose the second layer 210, which may be placed within, over,
on, or otherwise proximate to a tissue site, particularly a surface
tissue site and adjacent epidermis. The second layer 210 may be
interposed between the first layer 205 and the tissue site and
adjacent epidermis, which can substantially reduce or eliminate
adverse interaction with the first layer 205. For example, the
second layer 210 may be placed over a surface wound (including
edges of the wound) and undamaged epidermis to prevent direct
contact with the first layer 205. Treatment of a surface wound or
placement of the dressing 110 on a surface wound includes placing
the dressing 110 immediately adjacent to the surface of the body or
extending over at least a portion of the surface of the body.
Treatment of a surface wound does not include placing the dressing
110 wholly within the body or wholly under the surface of the body,
such as placing a dressing within an abdominal cavity. The cover
125 may be sealed to an attachment surface, such as epidermis
peripheral to a tissue site, around the first layer 205 and the
second layer 210.
[0069] The geometry and dimensions of the tissue interface 120, the
cover 125, or both may vary to suit a particular application or
anatomy. For example, the geometry or dimensions of the tissue
interface 120 and the cover 125 may be adapted to provide an
effective and reliable seal against challenging anatomical
surfaces, such as an elbow or heel, at and around a tissue site.
Additionally or alternatively, the dimensions may be modified to
increase the surface area for the second layer 210 to enhance the
movement and proliferation of epithelial cells at a tissue site and
reduce the likelihood of granulation tissue in-growth.
[0070] Thus, the dressing 110 in the example of FIG. 2 can provide
a sealed therapeutic environment proximate to a tissue site,
substantially isolated from the external environment, and the
negative-pressure source 105 can reduce the pressure in the sealed
therapeutic environment. Negative pressure in the sealed
environment may compress the first layer 205 into the second layer
210, which can deform the surface of the second layer 210 to
provide an uneven, coarse, or jagged profile that can induce
macrostrain and micro-strain in the tissue site in some
embodiments. Negative pressure applied through the tissue interface
120 can also create a negative pressure differential across the
fluid restrictions 220 in the second layer 210, which can open the
fluid restrictions 220 to allow exudate and other liquid movement
through the fluid restrictions 220 into the first layer 205 and the
container 115. For example, in some embodiments in which the fluid
restrictions 220 may comprise perforations through the second layer
210, a pressure gradient across the perforations can strain the
adjacent material of the second layer 210 and increase the
dimensions of the perforations to allow liquid movement through
them, similar to the operation of a duckbill valve.
[0071] In some embodiments, the first layer 205 may be hydrophobic
to minimize retention or storage of liquid in the dressing 110. In
other embodiments, the first layer 205 may be hydrophilic. In an
example in which the first layer 205 may be hydrophilic, the first
layer 205 may also wick fluid away from a tissue site, while
continuing to distribute negative pressure to the tissue site. The
wicking properties of the first layer 205 may draw fluid away from
a tissue site by capillary flow or other wicking mechanisms, for
example. An example of a hydrophilic first layer 205 is a polyvinyl
alcohol, open-cell foam such as V.A.C. WHITEFOAM.TM. dressing
available from KCI of San Antonio, Tex. Other hydrophilic foams may
include those made from polyether. Other foams that may exhibit
hydrophilic characteristics include hydrophobic foams that have
been treated or coated to provide hydrophilicity.
[0072] If the negative-pressure source 105 is removed or
turned-off, the pressure differential across the fluid restrictions
220 can dissipate, allowing the fluid restrictions 220 to return to
an unstrained or resting state and prevent or reduce the return
rate of exudate or other liquid moving to the tissue site through
the second layer 210.
[0073] In some applications, a filler may also be disposed between
a tissue site and the second layer 210. For example, if the tissue
site is a surface wound, a wound filler may be applied interior to
the periwound, and the second layer 210 may be disposed over the
periwound and the wound filler. In some embodiments, the filler may
be a manifold, such as an open-cell foam. The filler may comprise
or consist essentially of the same material as the first layer 205
in some embodiments.
[0074] Additionally or alternatively, the tissue interface 120 may
be formed into strips suitable for use as bridges or to fill tunnel
wounds, for example. Strips having a width of about 5 millimeters
to 30 millimeters may be suitable for some embodiments.
[0075] Additionally or alternatively, the second layer 210 may
comprise reinforcing fibers to increase its tensile strength, which
may be advantageous for use in tunnel wounds.
[0076] Additionally or alternatively, instillation solution or
other fluid may be distributed to the dressing 110, which can
increase the pressure in the tissue interface 120. The increased
pressure in the tissue interface 120 can create a positive pressure
differential across the fluid restrictions 220 in the second layer
210, which can open or expand the fluid restrictions 220 from their
resting state to allow the instillation solution or other fluid to
be distributed to the tissue site.
[0077] FIG. 4 is an assembly view of another example of the
dressing 110 of FIG. 1, illustrating additional details that may be
associated with some embodiments in which the tissue interface 120
may comprise additional layers. In the example of FIG. 4, the
tissue interface 120 comprises a third layer 405 in addition to the
first layer 205 and the second layer 210. In some embodiments, the
third layer 405 may be adjacent to the second layer 210 opposite
the first layer 205. The third layer 405 may also be bonded to the
second layer 210 in some embodiments.
[0078] The third layer 405 may comprise or consist essentially of a
sealing layer formed from a soft, pliable material suitable for
providing a fluid seal with a tissue site, and may have a
substantially flat surface. For example, the third layer 405 may
comprise, without limitation, a silicone gel, a soft silicone,
hydrocolloid, hydrogel, polyurethane gel, polyolefin gel,
hydrogenated styrenic copolymer gel, a foamed gel, a soft closed
cell foam such as polyurethanes and polyolefins coated with an
adhesive, polyurethane, polyolefin, or hydrogenated styrenic
copolymers. In some embodiments, the third layer 405 may have a
thickness between about 200 microns (.mu.m) and about 1000 microns
(.mu.m). In some embodiments, the third layer 405 may have a
hardness between about 5 Shore OO and about 80 Shore OO. Further,
the third layer 405 may be comprised of hydrophobic or hydrophilic
materials.
[0079] In some embodiments, the third layer 405 may be a
hydrophobic-coated material. For example, the third layer 405 may
be formed by coating a spaced material, such as, for example,
woven, nonwoven, molded, or extruded mesh with a hydrophobic
material. The hydrophobic material for the coating may be a soft
silicone, for example. Alternatively, the second layer 210 and the
third layer 405 may be omitted, and the first layer 205 may be at
least partially coated with a hydrophobic polymer, such as silicone
or polyethylene. For example, the first layer 205 may comprise or
consist essentially of a three-dimensional textile coated with
silicone. The coating may be continuous or discontinuous. In some
embodiments, only one side of the first layer 205 may be coated. In
other embodiments, both sides of the first layer 205 may be coated,
or the coating may be applied all the way through the first layer
205.
[0080] The third layer 405 may have a periphery 410 surrounding or
around an interior portion 415, and apertures 420 disposed through
the periphery 410 and the interior portion 415. The interior
portion 415 may correspond to a surface area of the first layer 205
in some examples. The third layer 405 may also have corners 425 and
edges 430. The corners 425 and the edges 430 may be part of the
periphery 410. The third layer 405 may have an interior border 435
around the interior portion 415, disposed between the interior
portion 415 and the periphery 410. The interior border 435 may be
substantially free of the apertures 420, as illustrated in the
example of FIG. 4. In some examples, as illustrated in FIG. 4, the
interior portion 415 may be symmetrical and centrally disposed in
the third layer 405.
[0081] The apertures 420 may be formed by cutting or by application
of local RF or ultrasonic energy, for example, or by other suitable
techniques for forming an opening. The apertures 420 may have a
uniform distribution pattern, or may be randomly distributed on the
third layer 405. The apertures 420 in the third layer 405 may have
many shapes, including circles, squares, stars, ovals, polygons,
slits, complex curves, rectilinear shapes, triangles, for example,
or may have some combination of such shapes.
[0082] Each of the apertures 420 may have uniform or similar
geometric properties. For example, in some embodiments, each of the
apertures 420 may be circular apertures, having substantially the
same diameter. In some embodiments, each of the apertures 420 may
have a diameter of about 1 millimeter to about 50 millimeters. In
other embodiments, the diameter of each of the apertures 420 may be
about 1 millimeter to about 20 millimeters.
[0083] In other embodiments, geometric properties of the apertures
420 may vary. For example, the diameter of the apertures 420 may
vary depending on the position of the apertures 420 in the third
layer 405, as illustrated in FIG. 4. In some embodiments, the
diameter of the apertures 420 in the periphery 410 of the third
layer 405 may be larger than the diameter of the apertures 420 in
the interior portion 415 of the third layer 405. For example, in
some embodiments, the apertures 420 disposed in the periphery 410
may have a diameter between about 9.8 millimeters and about 10.2
millimeters. In some embodiments, the apertures 420 disposed in the
corners 425 may have a diameter between about 7.75 millimeters and
about 8.75 millimeters. In some embodiments, the apertures 420
disposed in the interior portion 415 may have a diameter between
about 1.8 millimeters and about 2.2 millimeters.
[0084] At least one of the apertures 420 in the periphery 410 of
the third layer 405 may be positioned at the edges 430 of the
periphery 410, and may have an interior cut open or exposed at the
edges 430 that is in fluid communication in a lateral direction
with the edges 430. The lateral direction may refer to a direction
toward the edges 430 and in the same plane as the third layer 405.
As shown in the example of FIG. 4, the apertures 420 in the
periphery 410 may be positioned proximate to or at the edges 430
and in fluid communication in a lateral direction with the edges
430. The apertures 420 positioned proximate to or at the edges 430
may be spaced substantially equidistant around the periphery 410 as
shown in the example of FIG. 4. Alternatively, the spacing of the
apertures 420 proximate to or at the edges 430 may be
irregular.
[0085] As illustrated in the example of FIG. 4, in some
embodiments, the release liner 245 may be attached to or positioned
adjacent to the third layer 405 to protect the adhesive 240 prior
to use. In some embodiments, the release liner 245 may have a
surface texture that may be imprinted on an adjacent layer, such as
the third layer 405. Further, a release agent may be disposed on a
side of the release liner 245 that is configured to contact the
third layer 405.
[0086] FIG. 5 is a schematic view of an example configuration of
the apertures 420, illustrating additional details that may be
associated with some embodiments of the third layer 405. In some
embodiments, the apertures 420 illustrated in FIG. 5 may be
associated only with the interior portion 415. In the example of
FIG. 5, the apertures 420 are generally circular and have a
diameter D4, which may be about 2 millimeters in some embodiments.
FIG. 5 also illustrates an example of a uniform distribution
pattern of the apertures 420 in the interior portion 415. In FIG.
5, the apertures 420 are distributed across the interior portion
415 in a grid of parallel rows and columns. Within each row and
column, the apertures 420 may be equidistant from each other, as
illustrated in the example of FIG. 5. FIG. 5 illustrates one
example configuration that may be particularly suitable for many
applications, in which the apertures 420 are spaced a distance D5
apart along each row and column, with an offset of D6. In some
examples, the distance D5 may be about 6 millimeters, and the
offset D6 may be about 3 millimeters.
[0087] FIG. 6 is a schematic view of the example third layer 405 of
FIG. 5 overlaid on the second layer 210 of FIG. 3, illustrating
additional details that may be associated with some example
embodiments of the tissue interface 120. For example, as
illustrated in FIG. 6, the fluid restrictions 220 may be aligned,
overlapping, in registration with, or otherwise fluidly coupled to
the apertures 420 in some embodiments. In some embodiments, one or
more of the fluid restrictions 220 may be registered with the
apertures 420 only in the interior portion 415, or only partially
registered with the apertures 420. The fluid restrictions 220 in
the example of FIG. 6 are generally configured so that each of the
fluid restrictions 220 is registered with only one of the apertures
420. In other examples, one or more of the fluid restrictions 220
may be registered with more than one of the apertures 420. For
example, any one or more of the fluid restrictions 220 may be a
perforation or a fenestration that extends across two or more of
the apertures 420. Additionally or alternatively, one or more of
the fluid restrictions 220 may not be registered with any of the
apertures 420.
[0088] As illustrated in the example of FIG. 6, the apertures 420
may be sized to expose a portion of the second layer 210, the fluid
restrictions 220, or both through the third layer 405. In some
embodiments, one or more of the apertures 235 may be sized to
expose more than one of the fluid restrictions 220. For example,
some or all of the apertures 235 may be sized to expose two or
three of the fluid restrictions 220. In some examples, the length
of each of the fluid restrictions 220 may be substantially equal to
the diameter of each of the apertures 420. More generally, the
average dimensions of the fluid restrictions 220 are substantially
similar to the average dimensions of the apertures 420. For
example, the apertures 420 may be elliptical in some embodiments,
and the length of each of the fluid restrictions 220 may be
substantially equal to the major axis or the minor axis. In some
embodiments, though, the dimensions of the fluid restrictions 220
may exceed the dimensions of the apertures 420, and the size of the
apertures 420 may limit the effective size of the fluid
restrictions 220 exposed to the lower surface of the dressing
110.
[0089] Individual components of the dressing 110 in the example of
FIG. 4 may be bonded or otherwise secured to one another with a
solvent or non-solvent adhesive, or with thermal welding, for
example, without adversely affecting fluid management. Further, the
second layer 210 or the first layer 205 may be coupled to the
border 435 of the third layer 405 in any suitable manner, such as
with a weld or an adhesive, for example.
[0090] The cover 125, the first layer 205, the second layer 210,
the third layer 405, or various combinations may be assembled
before application or in situ. For example, the cover 125 may be
laminated to the first layer 205, and the second layer 210 may be
laminated to the first layer 205 opposite the cover 125 in some
embodiments. The third layer 405 may also be coupled to the second
layer 210 opposite the first layer 205 in some embodiments. In some
embodiments, one or more layers of the tissue interface 120 may be
coextensive. For example, the second layer 210, the third layer
405, or both may be cut flush with the edge of the first layer 205,
exposing the edge of the first layer 205. In other embodiments, the
second layer 210, the third layer 405, or both may overlap the edge
of the first layer 205. In some embodiments, the dressing 110 may
be provided as a single, composite dressing. For example, the third
layer 405 may be coupled to the cover 125 to enclose the first
layer 205 and the second layer 210, wherein the third layer 405 may
be configured to face a tissue site. Additionally or alternatively,
the second layer 210, the third layer 405, or both may be disposed
on both sides of the first layer 205 and bonded together to enclose
the first layer 205. In some examples, the third layer 405 may
comprise or be replaced with strips of similar or analogous
features. For example, strips of perforated silicone having a
backing with an adhesive coating may be advantageous. The strips
may be provided as a kit to be applied in situ, or may be applied
as an integrated edge border in a composite dressing in some
embodiments. A light-switchable adhesive may also be advantageous
in some examples.
[0091] In use, the release liner 245 (if included) may be removed
to expose the third layer 405 of the example of FIG. 4, which may
be placed within, over, on, or otherwise proximate to a tissue
site, particularly a surface tissue site and adjacent epidermis.
The third layer 405 and the second layer 210 may be interposed
between the first layer 205 and the tissue site, which can
substantially reduce or eliminate adverse interaction with the
first layer 205. For example, the third layer 405 may be placed
over a surface wound (including edges of the wound) and undamaged
epidermis to prevent direct contact with the first layer 205. In
some applications, the interior portion 415 of the third layer 405
may be positioned adjacent to, proximate to, or covering a tissue
site. In some applications, at least some portion of the second
layer 210, the fluid restrictions 220, or both may be exposed to a
tissue site through the third layer 405. The periphery 410 of the
third layer 405 may be positioned adjacent to or proximate to
tissue around or surrounding the tissue site. The third layer 405
may be sufficiently tacky to hold the dressing 110 in position,
while also allowing the dressing 110 to be removed or re-positioned
without trauma to the tissue site.
[0092] Removing the release liner 245 in the example of FIG. 4 can
also expose the adhesive 240 and the cover 125 may be attached to
an attachment surface, such as epidermis peripheral to a tissue
site, around the first layer 205 and the second layer 210. For
example, the adhesive 240 may be in fluid communication with an
attachment surface through the apertures 420 in at least the
periphery 410 of the third layer 405. The adhesive 240 may also be
in fluid communication with the edges 430 through the apertures 420
exposed at the edges 430.
[0093] Once the dressing 110 is in the desired position, the
adhesive 240 may be pressed through the apertures 420 to bond the
dressing 110 to the attachment surface. The apertures 420 at the
edges 430 may permit the adhesive 240 to flow around the edges 430
for enhancing the adhesion of the edges 430 to an attachment
surface.
[0094] In some embodiments, apertures or holes in the third layer
405 may be sized to control the amount of the adhesive 240 in fluid
communication with the apertures 420. For a given geometry of the
corners 425, the relative sizes of the apertures 420 may be
configured to maximize the surface area of the adhesive 240 exposed
and in fluid communication through the apertures 420 at the corners
425. For example, as shown in FIG. 4, the edges 430 may intersect
at substantially a right angle, or about 90 degrees, to define the
corners 425. In some embodiments, the corners 425 may have a radius
of about 10 millimeters. Further, in some embodiments, three of the
apertures 420 having a diameter between about 7.75 millimeters to
about 8.75 millimeters may be positioned in a triangular
configuration at the corners 425 to maximize the exposed surface
area for the adhesive 240. In other embodiments, the size and
number of the apertures 420 in the corners 425 may be adjusted as
necessary, depending on the chosen geometry of the corners 425, to
maximize the exposed surface area of the adhesive 240. Further, the
apertures 420 at the corners 425 may be fully housed within the
third layer 405, substantially precluding fluid communication in a
lateral direction exterior to the corners 425. The apertures 420 at
the corners 425 being fully housed within the third layer 405 may
substantially preclude fluid communication of the adhesive 240
exterior to the corners 425, and may provide improved handling of
the dressing 110 during deployment at a tissue site. Further, the
exterior of the corners 425 being substantially free of the
adhesive 240 may increase the flexibility of the corners 425 to
enhance comfort.
[0095] In some embodiments, the bond strength of the adhesive 240
may vary in different locations of the dressing 110. For example,
the adhesive 240 may have a lower bond strength in locations
adjacent to the third layer 405 where the apertures 420 are
relatively larger, and may have a higher bond strength where the
apertures 420 are smaller. Adhesive 240 with lower bond strength in
combination with larger apertures 420 may provide a bond comparable
to adhesive 240 with higher bond strength in locations having
smaller apertures 420.
[0096] The geometry and dimensions of the tissue interface 120, the
cover 125, or both may vary to suit a particular application or
anatomy. For example, the geometry or dimensions of the tissue
interface 120 and the cover 125 may be adapted to provide an
effective and reliable seal against challenging anatomical
surfaces, such as an elbow or heel, at and around a tissue site.
Additionally or alternatively, the dimensions may be modified to
increase the surface area for the third layer 405 to enhance the
movement and proliferation of epithelial cells at a tissue site and
reduce the likelihood of granulation tissue in-growth.
[0097] Further, the dressing 110 may permit re-application or
re-positioning to reduce or eliminate leaks, which can be caused by
creases and other discontinuities in the dressing 110 or a tissue
site. The ability to rectify leaks may increase the reliability of
the therapy and reduce power consumption in some embodiments.
[0098] Thus, the dressing 110 in the example of FIG. 4 can provide
a sealed therapeutic environment proximate to a tissue site,
substantially isolated from the external environment, and the
negative-pressure source 105 can reduce the pressure in the sealed
therapeutic environment. The third layer 405 may provide an
effective and reliable seal against challenging anatomical
surfaces, such as an elbow or heel, at and around a tissue site.
Further, the dressing 110 may permit re-application or
re-positioning, to correct air leaks caused by creases and other
discontinuities in the dressing 110, for example. The ability to
rectify leaks may increase the efficacy of the therapy and reduce
power consumption in some embodiments.
[0099] If not already configured, the dressing interface 255 may be
disposed over the aperture 260 and attached to the cover 125. The
fluid conductor 250 may be fluidly coupled to the dressing
interface 255 and to the negative-pressure source 105.
[0100] Negative pressure applied through the tissue interface 120
can create a negative pressure differential across the fluid
restrictions 220 in the second layer 210, which can open or expand
the fluid restrictions 220. For example, in some embodiments in
which the fluid restrictions 220 may comprise substantially closed
fenestrations through the second layer 210, a pressure gradient
across the fenestrations can strain the adjacent material of the
second layer 210 and increase the dimensions of the fenestrations
to allow liquid movement through them, similar to the operation of
a duckbill valve. Opening the fluid restrictions 220 can allow
exudate and other liquid movement through the fluid restrictions
220 into the first layer 205 and the container 115. Changes in
pressure can also cause the first layer 205 to expand and contract,
and the interior border 435 may protect the epidermis from
irritation. The second layer 210 and the third layer 405 can also
substantially reduce or prevent exposure of tissue to the first
layer 205, which can inhibit growth of tissue into the first layer
205.
[0101] If the negative-pressure source 105 is removed or turned
off, the pressure differential across the fluid restrictions 220
can dissipate, allowing the fluid restrictions 220 to close and
prevent exudate or other liquid from returning to the tissue site
through the second layer 210.
[0102] In some applications, a filler may also be disposed between
a tissue site and the third layer 405. For example, if the tissue
site is a surface wound, a wound filler may be applied interior to
the periwound, and the third layer 405 may be disposed over the
periwound and the wound filler. In some embodiments, the filler may
be a manifold, such as an open-cell foam. The filler may comprise
or consist essentially of the same material as the first layer 205
in some embodiments.
[0103] Additionally or alternatively, instillation solution or
other fluid may be distributed to the dressing 110, which can
increase the pressure in the tissue interface 120. The increased
pressure in the tissue interface 120 can create a positive pressure
differential across the fluid restrictions 220 in the second layer
210, which can open the fluid restrictions 220 to allow the
instillation solution or other fluid to be distributed to the
tissue site.
[0104] FIG. 7 is an assembly view of another example of the tissue
interface 120 of FIG. 1. In the example of FIG. 7, the second layer
210 is disposed adjacent to two sides of the first layer 205. In
some embodiments, for example, the second layer 210 may be
laminated or otherwise mechanically bonded to two sides of the
first layer 205. Additionally or alternatively, the third layer 405
may be disposed adjacent to one or more sides of the first layer
205, or may be disposed adjacent to the second layer 210 as shown
in the example of FIG. 7. In some embodiments, the third layer 405
may form a sleeve or envelope around the first layer 205, the
second layer 210, or both.
[0105] FIG. 8 is a perspective view of another example
configuration of the first layer 205 and the second layer 210. In
the example of FIG. 8, the second layer 210 may form a sleeve
around the first layer 205. For example, the second layer 210 may
be folded or rolled around the first layer 205, and edges of the
second layer 215 may be attached to each other. In other examples,
the edges may be attached to form a sleeve before inserting the
first layer 205, or the edges may be attached to the first layer
205. The second layer 210 may leave one or more edges of the first
layer 205 exposed, as illustrated in the example of FIG. 8. The
example configuration of FIG. 8 may be used in combination with or
instead of other configurations of the first layer 205 and the
second layer 210 described above.
[0106] FIG. 9 is a partial cutaway view of another example
configuration of the first layer and the second layer 210. In the
example of FIG. 9, the second layer 210 may form an envelope around
the first layer 205. For example, the second layer 210 may be
disposed on two sides of the first layer 205, and the edges may be
mechanically coupled to each other around the first layer 205 to
form an envelope. The example configuration of FIG. 9 may be used
in combination with or instead of other configurations of the first
layer 205 and the second layer 210 described above.
[0107] Additionally or alternatively, the second layer 210 may be
omitted from some configurations. For example, the second layer 210
may be omitted if the first layer 205 comprises a naturally highly
hydrophobic material, or is coated or treated to be highly
hydrophobic. In some embodiments, the first layer 205 may be
processed with a plasma system to coat polyethylene, polyolefin,
silicone, fluorosilicone, or another fluoropolymer onto a polyester
fabric. If the first layer 205 is a woven fabric, the knit of the
weave may also be adjusted to control the level of manifolding
through the first layer 205.
[0108] The systems, apparatuses, and methods described herein may
provide significant advantages. For example, some embodiments of
the dressing 110 may improve conformability for deeper wounds, and
may be advantageous for incisions or wounds over articulating
joints, such as a knee. Additionally, some dressings for
negative-pressure therapy can require time and skill to be properly
sized and applied to achieve a good fit and seal. In contrast, some
embodiments of the dressing 110 provide a negative-pressure
dressing that is simple to apply, reducing the time to apply and
remove. In some embodiments, for example, the dressing 110 may be a
fully-integrated negative-pressure therapy dressing that can be
applied to a tissue site (including on the periwound) in one step,
without being cut to size, while still providing or improving many
benefits of other negative-pressure therapy dressings that require
sizing. Such benefits may include good manifolding, beneficial
granulation, protection of the peripheral tissue from maceration,
protection of the tissue site from shedding materials, and a
low-trauma and high-seal bond. These characteristics may be
particularly advantageous for surface wounds having moderate depth
and medium-to-high levels of exudate. Some embodiments of the
dressing 110 may remain on the tissue site for at least 5 days, and
some embodiments may remain for at least 7 days. Antimicrobial
agents in the dressing 110 may extend the usable life of the
dressing 110 by reducing or eliminating infection risks that may be
associated with extended use, particularly use with infected or
highly exuding wounds.
[0109] While shown in a few illustrative embodiments, a person
having ordinary skill in the art will recognize that the systems,
apparatuses, and methods described herein are susceptible to
various changes and modifications that fall within the scope of the
appended claims. Moreover, descriptions of various alternatives
using terms such as "or" do not require mutual exclusivity unless
clearly required by the context, and the indefinite articles "a" or
"an" do not limit the subject to a single instance unless clearly
required by the context. Components may be also be combined or
eliminated in various configurations for purposes of sale,
manufacture, assembly, or use. For example, in some configurations
the dressing 110, the container 115, or both may be eliminated or
separated from other components for manufacture or sale. In other
example configurations, the controller 130 may also be
manufactured, configured, assembled, or sold independently of other
components.
[0110] The appended claims set forth novel and inventive aspects of
the subject matter described above, but the claims may also
encompass additional subject matter not specifically recited in
detail. For example, certain features, elements, or aspects may be
omitted from the claims if not necessary to distinguish the novel
and inventive features from what is already known to a person
having ordinary skill in the art. Features, elements, and aspects
described in the context of some embodiments may also be omitted,
combined, or replaced by alternative features serving the same,
equivalent, or similar purpose without departing from the scope of
the invention defined by the appended claims.
* * * * *