U.S. patent application number 16/577535 was filed with the patent office on 2020-01-09 for hybrid drape having a gel-coated perforated mesh.
The applicant listed for this patent is KCI Licensing, Inc.. Invention is credited to Christopher Brian LOCKE, Timothy Mark ROBINSON.
Application Number | 20200008980 16/577535 |
Document ID | / |
Family ID | 52595452 |
Filed Date | 2020-01-09 |
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United States Patent
Application |
20200008980 |
Kind Code |
A1 |
LOCKE; Christopher Brian ;
et al. |
January 9, 2020 |
HYBRID DRAPE HAVING A GEL-COATED PERFORATED MESH
Abstract
A system for treating a tissue site with negative-pressure is
described. The system includes a manifold configured to be
positioned adjacent to the tissue site and a drape configured to be
positioned over the tissue site and the manifold to form a sealed
space. The system also includes a negative-pressure source
configured to provide negative-pressure to the sealed space. The
drape includes a film layer, a layer of a bonding adhesive coupled
to the film layer, and a mesh coupled to the layer of the bonding
adhesive. The mesh includes a coating of a sealing adhesive and one
or more bonding apertures. Methods of manufacturing the drape are
also described.
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: |
52595452 |
Appl. No.: |
16/577535 |
Filed: |
September 20, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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14619714 |
Feb 11, 2015 |
|
|
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16577535 |
|
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|
61945882 |
Feb 28, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 13/0283 20130101;
A61F 13/0216 20130101; A61L 15/58 20130101; A61F 13/0253 20130101;
A61F 13/00068 20130101; A61F 13/025 20130101; A61M 1/0088 20130101;
Y10T 156/1062 20150115 |
International
Class: |
A61F 13/02 20060101
A61F013/02 |
Claims
1.-34. (canceled)
35. A method for manufacturing a drape for a negative-pressure
system, the method comprising: providing a film layer; coupling a
layer of a bonding adhesive to the film layer; forming a mesh;
coating the mesh with a sealing adhesive; forming one or more
bonding apertures in the mesh; and coupling the mesh to the layer
of the bonding adhesive.
36. The method of claim 35, wherein the bonding apertures are
formed in the mesh before coating the mesh.
37. The method of claim 35, wherein forming the mesh comprises
weaving a plurality of fibers to form the mesh.
38. The method of claim 35, wherein forming the mesh comprises
knitting a plurality of fibers to form the mesh.
39. The method of claim 35, wherein forming the mesh comprises
extruding a plurality of fibers to form the mesh.
40. The method of claim 39, wherein extruding the plurality of
fibers to form the mesh further comprises extruding the fibers so
that the fibers intersect with a prominence less than about 1
millimeter.
41. The method of claim 35, wherein the mesh comprises a plurality
of fibers and a diameter of each fiber is less than about 1
millimeter.
42. The method of claim 35, wherein the mesh comprises a plurality
of fibers and each fiber comprises a monofilament.
43. The method of claim 35, wherein the mesh comprises a plurality
of fibers and each fiber comprises a plurality of twisted
monofilaments.
44. The method of claim 35, wherein the mesh comprises a plurality
of fibers and each fiber comprises a staple fiber.
45. The method of claim 35, wherein forming the mesh comprises
forming the mesh from a plurality of fibers having intersections
and compressing the mesh to reduce a prominence at each
intersection of the fibers.
46. The method of claim 35, wherein forming the mesh comprises
forming the mesh from a plurality of fibers having intersections
and calendaring the mesh to reduce a prominence at each
intersection of the fibers.
47. The method of claim 35, wherein forming the mesh comprises
forming the mesh to have a plurality of mesh apertures each having
an effective diameter between about 0.5 millimeters and about 4
millimeters.
48. The method of claim 35, wherein coating the mesh comprises
applying a coating weight of the sealing adhesive between about 100
grams per square meter and about 500 grams per square meter.
49. The method of claim 35, wherein forming the bonding apertures
in the mesh comprises forming each bonding aperture with an
effective diameter between about 5 millimeters and about 15
millimeters.
50. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 14/619,714, filed Feb. 11, 2015, entitled "HYBRID DRAPE
HAVING A GEL-COATED PERFORATED MESH," which claims priority to and
the benefit of U.S. Provisional Patent Application No. 61/945,882,
filed Feb. 28, 2014, entitled "HYBRID DRAPE HAVING A GEL-COATED
PERFORATED MESH," each of which is hereby incorporated by reference
for all purposes.
FIELD
[0002] The present disclosure relates generally to dressings for
adhering to a wound or tissue site, and more particularly, but
without limitation, to a hybrid drape having a gel-coated
perforated mesh.
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," and "vacuum assisted closure," 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] While the clinical benefits of negative-pressure therapy are
widely known, the cost and complexity of negative-pressure therapy
can be a limiting factor in its application, and the development
and operation of negative-pressure systems, components, and
processes continues to present significant challenges to
manufacturers, healthcare providers, and patients.
SUMMARY
[0005] According to an illustrative, non-limiting embodiment, a
dressing for treating a tissue site with negative pressure is
described. The dressing may include a tissue interface configured
to be positioned adjacent to the tissue site; and a sealing member
configured to be positioned over the tissue interface and the
tissue site to form a sealed environment. The sealing member may
include a film layer, a layer of a bonding adhesive coupled to the
film layer, and a mesh coupled to the layer of the bonding
adhesive. The mesh may have a coating of a sealing adhesive and one
or more bonding apertures.
[0006] According to another illustrative embodiment, a system for
treating a tissue site with negative-pressure is described. The
system may include a manifold configured to be positioned adjacent
to the tissue site and a drape configured to be positioned over the
tissue site and the manifold to form a sealed space. The system may
also include a negative-pressure source configured to provide
negative-pressure to the sealed space. The drape may include a film
layer, a layer of a bonding adhesive coupled to the film layer, and
a mesh coupled to the layer of the bonding adhesive. The mesh may
have a coating of a sealing adhesive and one or more bonding
apertures.
[0007] According to another illustrative embodiment, a method for
manufacturing a drape for a negative-pressure system is described.
A film layer may be provided, and a layer of a bonding adhesive may
be coupled to the film layer. A mesh may be formed and coated with
a sealing adhesive. One or more bonding apertures may be formed in
the mesh, and the mesh may be coupled to the layer of the bonding
adhesive.
[0008] Other aspects, 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
[0009] Illustrative embodiments are described in detail below with
reference to the attached drawings, which are incorporated by
reference herein, and wherein:
[0010] FIG. 1 is a schematic diagram of an illustrative embodiment
of a system for treating a tissue site with negative pressure;
[0011] FIG. 2 is an exploded perspective view of a drape that may
be used with some embodiments of the systems of FIG. 1;
[0012] FIG. 3A is a plan view of a mesh that may be used with some
embodiments of the drape of FIG. 2;
[0013] FIG. 3B is a perspective view of a portion of the mesh of
FIG. 3A;
[0014] FIG. 3C is a side elevation view of a portion of the mesh of
FIG. 3A;
[0015] FIG. 4 is a sectional view illustrating additional details
that may be associated with some embodiments of the drape of FIG. 2
in a first state; and
[0016] FIG. 5 is a sectional view of the portion of the drape of
FIG. 4 in a second state.
DETAILED DESCRIPTION
[0017] 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 may
omit certain details already well-known in the art. The following
detailed description is, therefore, to be taken as illustrative and
not limiting.
[0018] 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.
[0019] FIG. 1 is a sectional view of an example embodiment of a
negative-pressure therapy system 100 illustrating details that may
be associated with some embodiments for treating a tissue site 102
with negative pressure. As shown in the illustrative embodiment of
FIG. 1, the negative-pressure therapy system 100 may include a
dressing 104 fluidly coupled to a negative-pressure source 106. In
some embodiments, the negative-pressure source 106 may be fluidly
coupled to the dressing 104 by a conduit, such as a tube 112, and a
connector, such as a connector 114. The dressing 104 may generally
include a drape, such as a drape 108, and a tissue interface, such
as a manifold 110. The drape 108 may have a film layer 124, a layer
of a bonding adhesive 126, and a mesh 128. The drape 108 may be
attached to an epidermis 116.
[0020] In general, components of the negative-pressure therapy
system 100 may be coupled directly or indirectly to each other. For
example, the negative-pressure source 106 may be directly coupled
to the connector 114 and indirectly coupled to the manifold 110
through the connector 114. Components may be fluidly coupled to
each other to provide a path for transferring fluids (such as,
liquid, gas, or both liquid and gas) between the components.
[0021] In some embodiments, components may be fluidly coupled with
a tube, such as the tube 112, for example. A "tube," as used
herein, broadly refers to a tube, pipe, hose, conduit, or other
structure with one or more lumina adapted to convey fluids between
two ends. Typically, a tube is an elongated, cylindrical structure
with some flexibility, but the geometry and rigidity may vary. In
some embodiments, components may additionally or alternatively be
coupled by virtue of physical proximity, being integral to a single
structure, or being formed from the same piece of material.
Coupling may also include mechanical, thermal, electrical, or
chemical coupling (such as a chemical bond) in some contexts.
[0022] In operation, a tissue interface, such as the manifold 110,
may be placed within, over, on, against, or otherwise adjacent to a
tissue site. For example, the manifold 110 may be placed against
the tissue site 102, and the drape 108 may be placed over the
manifold 110 and sealed to tissue proximate to the tissue site 102.
Tissue proximate to a tissue site is often undamaged epidermis
peripheral to the tissue site. Thus, the drape 108 can provide a
sealed therapeutic environment 118 proximate to the tissue site
102. The sealed therapeutic environment 118 may be substantially
isolated from the external environment, and the negative-pressure
source 106 can reduce the pressure in the sealed therapeutic
environment 118. Negative pressure applied uniformly through a
tissue interface in the sealed therapeutic environment 118 can
induce macrostrain and microstrain in the tissue site 102, as well
as remove exudates and other fluids from the tissue site. The
removed exudates and other fluids can be collected in a container
and disposed of properly.
[0023] The fluid mechanics of using a negative-pressure source to
reduce pressure in another component or location, such as within a
sealed therapeutic environment 118, can be mathematically complex.
However, the basic principles of fluid mechanics applicable to
negative-pressure therapy 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.
[0024] In general, exudates and other fluids flow toward lower
pressure along a fluid path. This orientation is generally presumed
for purposes of describing various features and components of
negative-pressure therapy systems herein. Thus, in the context of
negative-pressure therapy, the term "downstream" typically implies
something in a fluid path relatively closer to a negative-pressure
source, and conversely, the term "upstream" implies something
relatively further away from a negative-pressure source. Similarly,
it may be convenient to describe certain features in terms of fluid
"inlet" or "outlet" in such a frame of reference. However, a fluid
path may also be reversed in some applications, such as by
substituting a positive-pressure source, and this descriptive
convention should not be construed as a limiting convention.
[0025] The term "tissue site" in this context broadly refers to a
wound or defect 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 tissue that are not necessarily wounded or
defective, but are instead areas in which it may be desired to add
or promote the growth of additional tissue. For example, negative
pressure may be used in certain tissue areas to grow additional
tissue that may be harvested and transplanted to another tissue
location. In an illustrative embodiment, the tissue site 102 may be
a wound that extends through the epidermis 116, through a dermis
120, and into subcutaneous tissue 122.
[0026] "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 118
provided by the drape 108. In many cases, the local ambient
pressure may also be the atmospheric pressure in a patient's
vicinity. 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. Similarly, 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.
[0027] A negative-pressure source, such as the negative-pressure
source 106, may be a reservoir of air at a negative pressure, or
may be a manual or electrically-powered device that can reduce the
pressure in a sealed volume, such as a vacuum pump, a suction pump,
a wall-suction port available at many healthcare facilities, or a
micro-pump, for example. A negative-pressure source may be housed
within or used in conjunction with other components, such as
sensors, processing units, alarm indicators, memory, databases,
software, display devices, or operator interfaces that further
facilitate negative-pressure therapy. While the amount and nature
of negative pressure applied to a tissue site may vary according to
therapeutic requirements, the pressure typically ranges between -5
millimeters of mercury (mm Hg) (-667 Pa) and -500 mm Hg (-66.7
kPa). Common therapeutic ranges are between -75 mm Hg (-9.9 kPa)
and -300 mm Hg (-39.9 kPa).
[0028] A tissue interface, such as the manifold 110, can generally
be adapted to contact a tissue site or other layers of a dressing.
A tissue interface may be partially or fully in contact with a
tissue site. If a tissue site is a wound, for example, a tissue
interface may partially or completely fill the wound, or may be
placed over the wound. A tissue interface may take many forms, and
may be 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 a tissue interface may be adapted to the contours of deep and
irregular shaped tissue sites.
[0029] In some embodiments, a tissue interface may be a manifold,
such as the manifold 110. A "manifold" in this context generally
includes any substance or structure providing a plurality of
pathways adapted to collect or distribute fluid across a tissue
site under negative pressure. For example, a manifold may be
adapted to receive negative pressure from a source and distribute
the negative pressure through multiple apertures across a tissue
site, 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 across a tissue
site.
[0030] In some illustrative embodiments, the pathways of a manifold
may be channels interconnected to improve distribution or
collection of fluids across a tissue site. For example, cellular
foam, open-cell foam, reticulated foam, porous tissue collections,
and other porous material such as gauze or felted mat generally
include pores, edges, and/or walls adapted to form interconnected
fluid pathways. Liquids, gels, and other foams may also include or
be cured to include apertures and flow channels. In some
illustrative embodiments, a manifold may be a porous foam material
having interconnected cells or pores adapted to uniformly (or
quasi-uniformly) distribute negative pressure to a tissue site. The
foam material may be either hydrophobic or hydrophilic. In one
non-limiting example, a manifold may be an open-cell, reticulated
polyurethane foam such as GranuFoam.RTM. dressing available from
Kinetic Concepts, Inc. of San Antonio, Tex.
[0031] In some embodiments, such as embodiments in which the
manifold 110 may be made from a hydrophilic material, the manifold
110 may also wick fluid away from a tissue site while continuing to
distribute negative pressure to the tissue site. The wicking
properties of the manifold 110 may draw fluid away from a tissue
site by capillary flow or other wicking mechanisms. An example of a
hydrophilic foam is a polyvinyl alcohol, open-cell foam such as
V.A.C. WhiteFoam.RTM. dressing available from Kinetic Concepts,
Inc. 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.
[0032] A tissue interface may further promote granulation at a
tissue site if pressure within the sealed therapeutic environment
118 is reduced. For example, any or all of the surfaces of the
manifold 110 may have an uneven, coarse, or jagged profile that can
induce microstrains and stresses at a tissue site if negative
pressure is applied through the manifold 110.
[0033] In some example embodiments, a tissue interface may be
constructed from bioresorbable materials. Suitable bioresorbable
materials may include, without limitation, a polymeric blend of
polylactic acid (PLA) and polyglycolic acid (PGA). The polymeric
blend may also include without limitation polycarbonates,
polyfumarates, and capralactones. The tissue interface may further
serve as a scaffold for new cell-growth, or a scaffold material may
be used in conjunction with the tissue interface to promote
cell-growth. In general, a scaffold material may be a biocompatible
or biodegradable substance or structure used to enhance or promote
the growth of cells or formation of tissue, such as a
three-dimensional porous structure that provides a template for
cell growth. Illustrative examples of scaffold materials include
calcium phosphate, collagen, PLA/PGA, coral hydroxy apatites,
carbonates, or processed allograft materials.
[0034] In some embodiments, the drape 108 may provide a bacterial
barrier and protection from physical trauma. The drape 108 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 drape 108 may be, 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. In some example embodiments, the drape
108 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 about 25 microns to
about 50 microns. For permeable materials, the permeability
generally should be low enough that a desired negative pressure may
be maintained.
[0035] An attachment device may be used to attach the drape 108 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 that extends about a periphery, a
portion, or an entire sealing member. In some embodiments, for
example, some or all of the drape 108 may be coated with an acrylic
adhesive having a coating weight between about 25 grams per square
meter (gsm) to about 65 gsm. 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.
[0036] A "container" broadly includes a canister, pouch, bottle,
vial, or other fluid collection apparatus. A container, for
example, 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.
In some embodiments, a container may be a component of a
negative-pressure source, such as the negative-pressure source
106.
[0037] A "connector," such as the connector 114, may be used to
fluidly couple a tube to a sealed therapeutic environment. The
negative pressure developed by a negative-pressure source may be
delivered through a tube to a connector. In one illustrative
embodiment, a connector may be a T.R.A.C..RTM. Pad or Sensa
T.R.A.C..RTM. Pad available from Kinetic Concepts, Inc. of San
Antonio, Tex. In one exemplary embodiment, the connector 114 may
allow the negative pressure generated by the negative-pressure
source 106 to be delivered to the sealed therapeutic environment
118. In other exemplary embodiments, a connector may also be a tube
inserted through a drape.
[0038] Negative-pressure therapy is increasingly being performed
with smaller devices that use battery power rather than a
connection to an electrical outlet. Use of battery power decreases
the total power supply available to a device. As a result, power
drains that would be considered negligible in a device powered
through an electrical outlet connection may significantly reduce
the performance of a battery-powered device. Power drains may be
caused by low-level dressing leaks, for example, which can drain
power by repeatedly triggering operation of the a negative-pressure
source to maintain a therapeutic negative pressure at the tissue
site. Power drains can shorten the useful life of a device by
draining the device battery faster, requiring more frequent
disposal of the device, recharging of the battery, or battery
replacement. Leak detection techniques may help to identify some
leaks that may be sealed by the user; however, low-level leaks can
challenge the most sensitive leak detection systems and may often
go undetected.
[0039] Low-level dressing leaks may occur between a drape and
epidermis surrounding a tissue site if the drape fails to
completely seal to the epidermis. Generally, a drape suitable for
covering a tissue site for negative-pressure therapy may comprise a
film having a thickness between about 25 microns and about 50
microns that is water-vapor permeable and formed of a polymer. The
film, often formed of polyurethane, may be coated with an adhesive
having a coating weight between about 25 gsm and about 65 gsm. The
adhesive may often be acrylic-based and pressure sensitive. A
standard acrylic adhesive may have a bond strength between about
1.8 Newton/centimeter (N/cm) and about 3.8 N/cm on stainless steel
substrate at 23.degree. C. at 50% relative humidity based on the
American Society for Testing and Materials ("ASTM") standard ASTM
D3330. A pressure-sensitive adhesive increases in bond strength
when pressed against the surface to which the adhesive is being
bonded. In some applications, a pressure-sensitive adhesive may
undergo a physical change when compressed against a surface. In
other applications, a pressure-sensitive adhesive may flow into
crevices of a surface when compressed, increasing the bond strength
without undergoing a physical change. A drape using a standard
acrylic adhesive as described above is generally suitable for a
dressing where a negative-pressure source powered by a continuous
power supply is available to compensate for a dressing leak.
[0040] Some drapes may use a bonding adhesive instead of the
standard acrylic adhesive. A bonding adhesive may be an adhesive
having a bond strength that is greater than the bond strength of a
standard acrylic adhesive. In some embodiments, a bonding adhesive
may be a type of acrylic adhesive. A bonding adhesive may be better
for sealing, but the increased bond strength may cause
significantly more discomfort if the drape is removed. In addition,
removing a drape having a bonding adhesive may cause significant
damage to delicate or damaged skin.
[0041] A drape that has a sealing adhesive can fill gaps between
the drape and the epidermis to limit leaks and can be easy to
remove with low discomfort to the patient. Generally, a sealing
adhesive may have a lower bond strength than a standard acrylic
adhesive and a bonding adhesive. Generally, a sealing adhesive may
flow into gaps and crevices more readily than a standard acrylic
adhesive or a bonding adhesive. Various sealing, gap-filling
adhesives, such as silicone, hydrocolloids, and hydrogels, have
been used but each can have drawbacks. For example, hydrogel
adhesives are usually low tack and prone to swelling, creep, and
mobility when used with fluid systems. Available hydrogels and
hydrocolloids may not adhere well and may move when anchored. In
another example, silicone adhesives can fill gaps and seal, but are
not breathable and may lose mechanical bonding strength as the
silicone adhesives interact with moisture during use. To counter
these problems, silicone adhesives may require additional materials
to secure the silicone adhesive to a patient. For example, a
low-leak drape may be formed from two adhesive layers: a thick
sealing adhesive, perhaps in the shape of a gasket or ring, and a
thinner bonding adhesive layer used to keep the sealing adhesive in
place. Low-leak drapes constructed in this way can be more complex
than a drape using a single adhesive, increasing the complexity of
manipulation and operation.
[0042] A hybrid drape having a thick sealing layer that is
perforated and laminated over an adhesive-coated film can overcome
many of these challenges. For example, a hybrid drape may include a
film layer having a bonding adhesive applied directly to the film
layer, and a sealing adhesive applied directly to the bonding
adhesive. The sealing adhesive can be perforated to expose the
bonding adhesive. When the drape is applied to a patient, the
bonding adhesive can be pushed through the perforations of the
sealing adhesive to secure the sealing adhesive to the patient.
This laminated configuration may provide the benefits of the
sealing adhesive and the bonding adhesive over the entire drape
area. For example, the laminated configuration may be conformable
and of sufficient strength to ensure an initial seal, can inhibit
the development of typical low-level leaks, and can mechanically
affix to an epidermis without secondary processes. The laminated
configuration may also minimize application care by a user and can
be removable with minimal trauma to a patient.
[0043] However, construction of a laminated configuration can
require additional assembly steps and can increase an amount of
materials that may be needed for drape construction, which can also
significantly increase costs. In addition, as two layers of
adhesive are applied to the film layer, the total thickness of the
drape can significantly increase, reducing breathability of the
drape. Still further, as two full layers of adhesive are applied,
significantly more adhesive material is needed to construct the
drape.
[0044] Other hybrid drapes may register a bonding adhesive and a
sealing adhesive. These hybrid drapes apply both a bonding adhesive
and a sealing adhesive directly to a film layer. The bonding
adhesive and the sealing adhesive may each cover different portions
of a film layer to reduce the overall thickness of a hybrid drape
and decrease the amount of adhesive needed to construct the hybrid
drape. However, the complexity of the manufacturing process may
also increase costs relative to other drapes. While using less
adhesive than the laminated hybrid drapes, registered hybrid drapes
may still use more adhesive in construction than standard
drapes.
[0045] Some hybrid drapes may use a gel coated mesh having mesh
apertures with a diameter between about 5 millimeters (mm) and
about 15 mm. However, a gel-coated mesh having apertures of this
size may be unable to form a seal with a tissue site. The sealing
properties of the gel-coated mesh may be improved by increasing an
average diameter of the fibers used to form the mesh; however, the
increased diameter of the fibers may also increase a prominence of
a mesh where two fibers intersect. A prominence may be a relative
height of a feature compared to surrounding features. If two fibers
intersect so that a first fiber overlaps a second fiber, a
prominence may be a distance between a top of a first fiber and the
top of the second fiber. Generally, the prominence at an
intersection of two fibers may be the diameter of the largest of
the two intersecting fibers. Consequently, if the diameters of the
fibers are increased to increase the sealing properties of a
gel-coated mesh, the raised contours associated with fiber
cross-over may create leaks that are difficult to seal.
[0046] As disclosed herein, the negative-pressure therapy system
100 can overcome these challenges and others by providing a
substantially flat mesh coated with a sealing adhesive. In some
embodiments, for example, the drape 108 may comprise a layer of a
bonding adhesive coupled to a film layer, and a mesh layer coupled
to the layer of bonding adhesive. The mesh layer may be a mesh
formed of small diameter fibers and can be perforated to form
bonding apertures. The mesh may be coated with a sealing
adhesive.
[0047] FIG. 2 is an exploded perspective view, illustrating details
that may be associated with some embodiments of the drape 108. The
film layer 124 may be liquid-impermeable and vapor-permeable,
allowing vapor to egress and inhibiting liquid from exiting. The
film layer 124 may be a flexible film that is breathable and may
have a high moisture-vapor transfer rate (MVTR). For example, in
some embodiments, the MVTR may be greater than or equal to about
300 g/m.sup.2/24 hours. The film layer 124 may be formed from a
range of medically approved films that typically range in thickness
from about 15 microns (.mu.m) to about 50 microns (.mu.m). In other
embodiments, a drape having a low MVTR or that allows no vapor
transfer may be used. The film layer 124 can also function as a
barrier to liquids and microorganisms.
[0048] The film layer 124 may be formed from numerous materials,
such as one or more of the following: hydrophilic polyurethane
(PU), cellulosics, hydrophilic polyamides, polyvinyl alcohol,
polyvinyl pyrrolidone, hydrophilic acrylics, hydrophilic silicone
elastomers, and copolymers of these. In an illustrative embodiment,
the film layer 124 may be formed from a breathable cast matt
polyurethane film sold by Expopack Advanced Coatings of Wrexham,
United Kingdom, under the name INSPIRE 2301. The illustrative film
may have an MVTR (inverted cup technique) of 14400 g/m.sup.2/24
hours and may be approximately 30 microns thick.
[0049] The bonding adhesive 126 may be coupled directly to the film
layer 124. The bonding adhesive 126 may be a medically-acceptable,
pressure-sensitive adhesive. For example, the bonding adhesive 126
may be formed from an acrylic adhesive, rubber adhesive, high-tack
silicone adhesive, polyurethane, or other substance. In some
illustrative embodiments, the bonding adhesive 126 may be formed
from an acrylic adhesive with a coating weight of about 15 gsm to
about 70 gsm. The bonding adhesive 126 may also be a high-bond
strength acrylic adhesive, patterrubber adhesive, high-tack
silicone adhesive, or polyurethane, for example. In some
embodiments, the bonding adhesive 126 may have a peel adhesion or
resistance to being peeled from a stainless steel material between
about 6N/25 mm to about 10N/25 mm on stainless steel substrate at
23.degree. C. at 50% relative humidity based on the ASTM D3330.
[0050] The bonding adhesive 126 may be a continuous layer of
material or may be a layer with apertures (not shown). The
apertures may be formed after application of the bonding adhesive
126 or may be formed by coating the bonding adhesive 126 in
patterns on a carrier layer. The apertures may be sized to help
control the resultant tackiness of the bonding adhesive 126. The
apertures may also be sized to enhance the MVTR of the drape 108.
The bonding adhesive 126 may couple the film layer 124 to the mesh
128.
[0051] In some embodiments, the mesh 128 may be a polymeric mesh,
such as Mepitel.RTM. produced by Molnlycke Health Care,
Adaptic.RTM. produced by Systagenix, and Noveface produced by
Zodiac Aerospace Group. In some embodiments, the mesh 128 may be
substantially flat. For example, the mesh 128 may have a thickness
129, and individual portions of the mesh 128 may have a minimal
tolerance from the thickness 129. In some embodiments, the
thickness 129 of the mesh 128 may be about 1 mm, and the tolerance
of the thickness 129 may be less than about 2 mm. In another
exemplary embodiment, a tolerance of the thickness 129 of the mesh
128 may be less than about 1 mm. In other embodiments, a tolerance
of the thickness 129 of the mesh 128 may be less than about 0.5 mm.
In some embodiments, the mesh 128 may be formed with bonding
apertures 134. The bonding apertures 134 may be numerous shapes,
for example, circles, squares, stars, ovals, polygons, slits,
complex curves, rectilinear shapes, triangles, or other shapes.
[0052] FIG. 3A is a plan view, illustrating details that may be
associate with some embodiments of the mesh 128. Generally, a mesh
may include a structure of connected strands of metal, fiber, or
other flexible or ductile material having openings between the
strands. In some embodiments, a mesh may have evenly spaced
openings between adjacent strands. In some embodiments, the mesh
128 may have a plurality of fibers 136. In some embodiments, the
fibers 136 may be formed from a monofilament, a plurality of
twisted monofilaments, a plurality of filaments, or a plurality of
staple fibers. A filament may be a fiber that is formed in a
continuous or near-continuous length. A monofilament may be a
single filament. In some embodiments, a monofilament may be made
from a single synthetic fiber of plastic, for example.
Monofilaments may have a tensile strength related to a diameter of
the monofilament and the type of material from which the
monofilament is formed. A staple fiber may be a fiber of a selected
standardized length, and the staple fiber may be formed of a
suitable composition for used with a medical device. Each of the
fibers 136 may have a diameter 127. In some embodiments, the
diameter 127 may be no greater than about 1 mm. The fibers 136 may
be formed from a range of materials including, but not limited to,
silicone, cellulose acetate, and other similar materials.
[0053] In some embodiments, antimicrobial agents may be added to
the mesh 128. In other embodiments, the fibers 136 may have
antimicrobial properties. For example, in some embodiments, silver
ions may be added to the fibers 136. In still other embodiments,
the fibers 136 may be formed from elastomers to permit easier
coverage of complex contours.
[0054] The plurality of fibers 136 may be woven, knitted, knotted,
linked or otherwise connected to form a regular pattern of mesh
apertures. In some embodiments, each of the plurality of fibers 136
may be separated from adjacent fibers 136 to form mesh apertures
139. In some embodiments, the fibers 136 may be separated a
distance 138 from adjacent fibers, which may be between about 0.5
mm and about 4 mm. In some embodiments, each of the fibers 136 may
be separated from adjacent fibers in a second direction by a
distance 140. In some embodiments, the distance 140 may be between
about 0.5 mm and about 4 mm. In some embodiments, the first
direction of the distance 138 and the second direction of the
distance 140 may be perpendicular. In some embodiments, the
distance 138 and the distance 140 may be the same. In other
embodiments, the first direction of the distance 138 and the second
direction of the distance 140 may be other angles, and the distance
138 and the distance 140 may not be the same.
[0055] In some embodiments, the mesh apertures 139 may have an
average effective diameter of about 1 mm. An effective diameter of
a non-circular area may be a diameter of a circular area having the
same surface area as the non-circular area. For example, the
surface area of a mesh aperture 139 where the distance 138 is 0.5
mm and the distance 140 is 0.5 mm may be 0.25 mm.sup.2. The
diameter of a circular area having a 0.25 mm.sup.2 surface area is
about 0.56 mm; consequently, the effective diameter of the
exemplary mesh aperture 139 is about 0.56 mm. Similarly, if the
distance 138 is about 4 mm and the distance 140 is about 4 mm, the
effective diameter of the mesh aperture 139 may be about 4.51
mm.
[0056] In some embodiments, the mesh 128 may include the bonding
apertures 134. The bonding apertures 134 may have a uniform pattern
or may be randomly distributed on the mesh 128. The bonding
apertures 134 may be formed through one or more fibers 136. In some
embodiments, the bonding apertures 134 may extend into the mesh
apertures 139. Each bonding aperture 134 of the plurality of
bonding apertures 134 may have an effective diameter. The average
effective diameter of each bonding aperture 134 may be in the range
of about 5 mm to about 15 mm.
[0057] In some embodiments, the mesh 128 may be coated with a gel,
such as a sealing adhesive 144. In some embodiments, the sealing
adhesive 144 may have a coating weight of about 100 gsm to about
500 gsm. In other embodiments, the sealing adhesive 144 may have a
coating weight greater than about 200 gsm. The coating of the mesh
128 with the sealing adhesive 144 may fill in a portion of each
mesh aperture 139. In some embodiments, the mesh apertures 139 may
remain at least partially open after the coating of the mesh 128
with the sealing adhesive 144.
[0058] A sealing adhesive may be a soft material that provides a
good seal with the tissue site 102. A sealing adhesive may be
formed of a silicone gel (or soft silicone), hydrocolloid,
hydrogel, polyurethane gel, polyolefin gel, hydrogenated styrenic
copolymer gels, or foamed gels with compositions as listed, or soft
closed cell foams (polyurethanes, polyolefins) coated with an
adhesive (for example, 30 gsm-70 gsm acrylic), polyurethane,
polyolefin, or hydrogenated styrenic copolymers. In some
embodiments, a sealing adhesive may have a stiffness between about
5 Shore OO and about 80 Shore OO. A sealing adhesive may be
hydrophobic or hydrophilic. A sealing adhesive may be an adhesive
having a low to medium tackiness, for example, a silicone polymer,
polyurethane, or an additional acrylic adhesive. In some
embodiments, a sealing adhesive may a bond strength between about
0.5N/25 mm and about 1.5N/25 mm on a stainless steel substrate at
23.degree. C. at 50% relative humidity based on ASTM D3330. A
sealing adhesive may have a tackiness such that the sealing
adhesive may achieve the bond strength above after a contact time
of less than 60 seconds. Tackiness may be considered a bond
strength of an adhesive after a very low contact time between the
adhesive and a substrate. In an illustrative embodiment, a sealing
adhesive may have a tackiness that may be about 30% to about 50% of
the tackiness of a bonding adhesive.
[0059] In some embodiments, the bonding apertures 134 may be formed
prior to coating of the mesh 128 with the sealing adhesive 144. In
other embodiments, the bonding apertures 134 may be formed in the
mesh 128 following coating of the mesh 128 with the sealing
adhesive 144.
[0060] In some embodiments, the fibers 136 of the mesh 128 may form
a plurality of intersections 142. In some embodiments, an
intersection 142 may be a location of the mesh 128 where at least
two fibers 136 overlap, cross-over, or meet, for example.
[0061] FIG. 3B is a perspective view, illustrating additional
details that may be associated with some embodiments of the mesh
128 of FIG. 3A. In some embodiments, the mesh 128 may be formed so
that at each intersection 142, the intersecting fibers 136 may be
fused so that the intersection 142 is planar. In some embodiments,
the mesh 128 may be molded, extruded, or expanded to form the mesh
128. In embodiments where the mesh 128 is molded, extruded, or
expanded, the fibers 136 at an intersection 142 may be fused or
joined so that a prominence at the intersection 142 is less than
about 1 mm. In some embodiments, the prominence at an intersection
142 may be about 0 mm. In some embodiments, a substantially flat
mesh may have a thickness at the intersections 142 that may be
substantially the same as a thickness of the mesh 128 surrounding
the intersections 142.
[0062] FIG. 3C is a side elevation view, illustrating additional
details that may be associated with some embodiments of the mesh
128. In some embodiments, the mesh 128 may be formed by weaving or
knitting the fibers 136. If the fibers 136 are woven or knitted,
the intersections 142 may have a prominence 141. In some
embodiments, the prominence 141 of the fibers 136 at the
intersections 142 may be equal to the diameter 127 of the fibers
136. In some embodiments, the prominence 141 may be reduced by
compressing the mesh 128 following weaving or knitting the fibers
136. The prominences 141 of the fibers 136 may also be reduced by
passing the mesh 128 through a calender, which may apply pressure
to the mesh 128 to smooth out the mesh 128. In some embodiments,
the prominence 141 may be less than about 1 mm.
[0063] FIG. 4 is a sectional view, illustrating additional details
that may be associated with some embodiments of the drape 108. In
the assembled state, the bonding adhesive 126 may be coupled to the
film layer 124, and the mesh 128 may be coupled to the bonding
adhesive 126. If the mesh 128 is placed proximate to or in contact
with the epidermis 116, the sealing adhesive 144 coating the mesh
128 may form sealing couplings 146 with the epidermis 116. In some
embodiments, the diameter 127 of the fibers 136, the thickness of
the sealing adhesive 144, and the bonding apertures 134 may create
a gap between the bonding adhesive 126 and the epidermis 116.
[0064] FIG. 5 is a sectional view, illustrating additional details
that may be associated with some embodiments of the drape 108 of
FIG. 4 in a second position. If the drape 108 is in a desired
location, pressure may be applied to the film layer 124. The
pressure may cause the bonding adhesive 126 to be pressed at least
partially into contact with the epidermis 116 to form bonding
couplings 150. The bonding couplings 150 may provide secure,
releasable mechanical fixation to the epidermis 116. The sealing
couplings 146 between the sealing adhesive 144 and the epidermis
116 may be sufficient to seal the film layer 124 to the epidermis
116. The sealing couplings 146 may not be as mechanically strong as
the bonding couplings 150 between the bonding adhesive 126 and the
epidermis 116. The bonding couplings 150 may also anchor the drape
108 to the epidermis 116, inhibiting migration of the drape 108 and
the sealing adhesive 144.
[0065] The average effective diameter of the bonding apertures 134
of the sealing adhesive 144 may be varied as one control of the
tackiness or adhesion strength of the drape 108. In this regard,
there may be an interplay between three main variables for each
embodiment: the diameter 127 of the fibers 136, the average
effective diameter of the plurality of bonding apertures 134, and
the tackiness of the bonding adhesive 126. The more bonding
adhesive 126 that extends through the bonding apertures 134, the
stronger the bonding coupling 150. The smaller the diameter 127 of
the fibers 136, the more the bonding adhesive 126 generally extends
through the bonding apertures 134 and the greater the bonding
coupling 150. As an example of the interplay, if a very tacky
bonding adhesive 126 is used and the diameter 127 of the fibers 136
of the mesh 128 is small, the average effective diameter of the
plurality of bonding apertures 134 may be relatively smaller to
maintain a same adhesion strength of the drape 108.
[0066] In other embodiments, the mesh 128 may be formed from a
perforated film which is then coated with the sealing adhesive 144
and laminated to the film layer 124 or the bonding adhesive 126. In
other embodiments, the mesh 128 may be coated with the bonding
adhesive 126 and then pattern-coated with the sealing adhesive 144.
The mesh 128 may then be laminated directly to the film layer 124.
The bonding adhesive 126 may be exposed through the areas of the
mesh 128 that were not pattern-coated with the sealing adhesive
144.
[0067] In some embodiments, the adhesives may be mixed with blowing
or expanding agents, for example organic and inorganic low
temperature boiling point liquids. The blowing or expanding agents
allow for the adhesives to expand under the application of heat or
light to increase the thickness of the adhesive following
deposition by one of the above described processes. The blowing or
expanding agents may reduce the amount of adhesive needed and
decrease the cost of production. In some embodiments, the
application of heat or light may be delayed until application of
the drape 108 to the epidermis 116 so that the contact area with
the epidermis 116 may increase as the bonding adhesive 126 and the
sealing adhesive 144 warm by contact with the epidermis 116. The
application of light or heat following application of the drape 108
to the epidermis 116 can provide a better seal for some embodiments
of the drape 108 to the epidermis 116.
[0068] A drape having a coated mesh may provide a lower cost
solution that makes more efficient use of a sealing adhesive. The
increase in efficiency of the use of a sealing adhesive may be
accomplished without the complication of adding extruders and
pattern coaters that may be required for pattern printing of
adhesives. A drape having a coated mesh may have a higher MVTR than
other drapes as the inclusion of mesh apertures can permit greater
passage of moisture without interfering with sealing.
[0069] Although certain features and their advantages have been
disclosed in the context of certain illustrative, non-limiting
embodiments, it should be understood that various changes,
substitutions, permutations, and alterations can be made without
departing from the scope of the appended claims. It will be
appreciated that features that may be described in connection to
one embodiment may also be applicable to other embodiments. It will
also be understood that the benefits and advantages described above
may relate to one embodiment or may relate to several embodiments.
It will further be understood that reference to "an" item refers to
one or more of those items.
[0070] The steps of the methods described herein may be carried out
in a suitable order, or simultaneously where appropriate.
[0071] Where appropriate, aspects of the embodiments described
above may be combined with aspects of the other embodiments
described to form further examples having comparable or different
properties and addressing the same or different problems.
[0072] It will be understood that the embodiments described herein
are given by way of example only and that various modifications may
be made by those skilled in the art. The above specification,
examples and data provide a complete description of the structure
and use of exemplary embodiments. Although various embodiments have
been described above with a certain degree of particularity, or
with reference to one or more individual illustrations, those
skilled in the art could make numerous alterations to the example
embodiments without departing from the scope of the claims.
* * * * *