U.S. patent application number 17/198667 was filed with the patent office on 2021-07-01 for ion exchange enhanced absorbent systems.
The applicant listed for this patent is KCI Licensing, Inc.. Invention is credited to Christopher Brian LOCKE, Timothy Mark ROBINSON.
Application Number | 20210196868 17/198667 |
Document ID | / |
Family ID | 1000005447942 |
Filed Date | 2021-07-01 |
United States Patent
Application |
20210196868 |
Kind Code |
A1 |
ROBINSON; Timothy Mark ; et
al. |
July 1, 2021 |
ION EXCHANGE ENHANCED ABSORBENT SYSTEMS
Abstract
A system, method, and apparatus for treating a tissue site with
reduced pressure includes a dressing adapted to be positioned
proximate the tissue site. An absorbent may be adapted to be
fluidly coupled to the manifold, and an ion exchange member may be
adapted to be fluidly coupled between the manifold and the
absorbent. A sealing member may be adapted to cover the tissue site
to form a sealed space having the manifold disposed therein. A
reduced-pressure source may be adapted to be fluidly coupled to the
manifold.
Inventors: |
ROBINSON; Timothy Mark;
(Shillingstone, GB) ; LOCKE; Christopher Brian;
(Bournemouth, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KCI Licensing, Inc. |
San Antonio |
TX |
US |
|
|
Family ID: |
1000005447942 |
Appl. No.: |
17/198667 |
Filed: |
March 11, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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14150216 |
Jan 8, 2014 |
10973962 |
|
|
17198667 |
|
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61753373 |
Jan 16, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M 1/84 20210501; A61M
1/88 20210501; A61M 1/784 20210501; A61M 1/882 20210501; A61M 1/90
20210501; A61M 1/0023 20130101; A61F 13/00068 20130101 |
International
Class: |
A61M 1/00 20060101
A61M001/00; A61F 13/00 20060101 A61F013/00 |
Claims
1.-14. (canceled)
15. A method for treating a tissue site, the method comprising:
disposing a manifold proximate the tissue site; fluidly coupling an
ion exchange member to the manifold; fluidly coupling an absorbent
to the ion exchange member and the manifold; sealing the manifold
to the tissue site with a sealing member; fluidly coupling a
reduced-pressure source to the manifold, the ion exchange member,
and the manifold; supplying reduced pressure to the tissue site to
draw fluid from the tissue site to the absorbent through the ion
exchange member; and reducing an ionic concentration of the fluid
with the ion exchange member.
16. The method of claim 15, further comprising positioning the ion
exchange member between the manifold and the sealing member.
17. The method of claim 15, further comprising positioning the ion
exchange member between the manifold and the sealing member and
positioning the absorbent between the ion exchange member and the
sealing member.
18. The method of claim 15, further comprising positioning the ion
exchange member between the manifold and the sealing member and
positioning the absorbent in a container.
19. The method of claim 15, wherein the method further comprises:
fluidly coupling the manifold to the reduced-pressure source with a
tube having at least one lumen; disposing an absorbent in a portion
of the lumen; and positioning the ion exchange member between the
manifold and the sealing member.
20. The method of claim 15, wherein the method further comprises:
fluidly coupling the manifold to the reduced-pressure source with a
tube having at least one lumen; and positioning the ion exchange
member in the lumen.
21. The method of claim 15, wherein the method further comprises:
disposing the absorbent in a container; fluidly coupling the
container between the manifold and the reduced-pressure source with
a tube having at least one lumen; and positioning the ion exchange
member in the tube.
22. The method of claim 15, wherein the method further comprises:
fluidly coupling the manifold to the reduced-pressure source with a
tube having at least one lumen; disposing the absorbent in a
portion of the lumen; and positioning the ion exchange member in
another portion of the lumen between the manifold and the
absorbent.
23. A dressing for treating a tissue site, the dressing comprising:
a manifold adapted to be positioned adjacent the tissue site for
receiving reduced pressure; an ion exchange layer adapted to be
positioned adjacent the manifold and fluidly coupled to the
manifold; and an absorbent adapted to be positioned adjacent the
ion exchange layer and fluidly coupled to the ion exchange layer
and the manifold.
24. The dressing of claim 23, wherein a surface area of the ion
exchange layer adjacent the absorbent and a surface area of the
absorbent adjacent the ion exchange layer are substantially the
same.
25. The dressing of claim 23, further comprising a sealing member
adapted to be positioned over the ion exchange layer and the
absorbent and further adapted to be fluidly sealed to an area
adjacent the tissue site.
26. The dressing of claim 23, wherein the ion exchange layer
comprises porous beads formed from crosslinked polymers doped or
grafted with acidic polymers.
27. The dressing of claim 23, wherein: the ion exchange layer
comprises porous beads formed from crosslinked polymers doped or
grafted with acidic polymers; the crosslinked polymers comprise
polystyrene; and the acidic polymers comprise poly
(2-acrylamido-2-methyl-1-propanesulfonic acid) and poly
(acrylamido-N-propyltrimethylammonium chloride).
28. The dressing of claim 23, wherein the ion exchange layer
comprises a zeolite.
29. The dressing of claim 23, wherein the ion exchange layer
comprises activated charcoal.
30. The dressing of claim 23, wherein the ion exchange layer
comprises Carbon 100% activated carbon.
31. A container for storing fluids from a tissue site, the
container comprising: a body having an interior portion, a fluid
inlet, and a fluid outlet; an absorbent disposed in the interior
and adapted to absorb fluid from the tissue site; and an ion
exchange member coupled to the fluid inlet and fluidly coupled to
the absorbent.
32. The container of claim 31, wherein the ion exchange member
comprises porous beads formed from crosslinked polymers doped or
grafted with acidic polymers.
33. The container of claim 31, wherein: the ion exchange member
comprises porous beads formed from crosslinked polymers doped or
grafted with acidic polymers; the crosslinked polymers comprise
polystyrene; and the acidic polymers comprise poly
(2-acrylamido-2-methyl-1-propanesulfonic acid) and poly
(acrylamido-N-propyltrimethylammonium chloride).
34. The container of claim 31, wherein the ion exchange member
comprises a zeolite.
35. The container of claim 31, wherein the ion exchange member
comprises activated charcoal.
36. The container of claim 31, wherein the ion exchange member
comprises 100% activated carbon.
37. A tube for transmitting fluid from a tissue site to a
container, the tube comprising: a cylindrical body having at least
one lumen; and an ion exchange insert disposed within the lumen so
that fluid transmitted through the lumen passes through the ion
exchange insert.
38. The tube of claim 37, wherein the cylindrical body is
flexible.
39. The tube of claim 37, wherein the ion exchange insert comprises
porous beads formed from crosslinked polymers doped or grafted with
acidic polymers.
40. The tube of claim 37, wherein: the ion exchange insert
comprises porous beads formed from crosslinked polymers doped or
grafted with acidic polymers; the crosslinked polymers comprise
polystyrene; and the acidic polymers comprise poly
(2-acrylamido-2-methyl-1-propanesulfonic acid) and poly
(acrylamido-N-propyltrimethylammonium chloride).
41. The tube of claim 37, wherein the ion exchange insert comprises
a zeolite.
42. The tube of claim 37, wherein the ion exchange insert comprises
activated charcoal.
43. The tube of claim 37, wherein the ion exchange insert comprises
100% activated carbon.
44. The tube of claim 37, wherein the lumen has a first portion and
a second portion, the first portion of the lumen having the ion
exchange insert disposed therein and the second portion of the
lumen having an absorbent disposed therein.
Description
RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 14/150,216, filed Jan. 8, 2014, which claims the benefit,
under 35 U.S.C. .sctn. 119(e), of the filing of U.S. Provisional
Patent Application No. 61/753,373 filed Jan. 16, 2013, entitled
"Ion Exchange Enhanced Absorbent Systems," which are incorporated
herein by reference for all purposes.
TECHNICAL FIELD
[0002] The present disclosure relates generally to medical
treatment systems for treating tissue sites and processing fluids.
More particularly, but not by way of limitation, the present
disclosure relates to absorbent dressings having ion exchange media
disposed therein.
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 with
reduced pressure may be commonly referred to as "reduced-pressure
wound therapy," but is also known by other names, including
"negative-pressure therapy," "negative pressure wound therapy," and
"vacuum therapy," for example. Reduced-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 reduced-pressure therapy are
widely known, the cost and complexity of reduced-pressure therapy
can be a limiting factor in its application, and the development
and operation of reduced-pressure systems, components, and
processes continues to present significant challenges to
manufacturers, healthcare providers, and patients. In particular,
reduced-pressure therapy systems incorporating absorbents formed of
superabsorbent polymers often experience a real world absorption
capacity that is less than the rated absorption capacity. This may
necessitate the use of additional absorbent or increase the number
of dressing changes necessary to treat a tissue site. Increasing
the amount of absorbent used and the number of dressing changes can
negatively impact the ability to provide reduced-pressure
therapy.
SUMMARY
[0005] According to an exemplary embodiment, a system for treating
a tissue site with reduced pressure is described. The system may
include a manifold adapted to be positioned adjacent the tissue
site. The system may also include an absorbent adapted to be
fluidly coupled to the manifold. The system may further include an
ion exchange member adapted to be fluidly coupled between the
manifold and the absorbent. The system may have a sealing member
adapted to cover the tissue site to form a sealed space having the
manifold disposed therein and a reduced-pressure source adapted to
be fluidly coupled to the manifold.
[0006] According to another exemplary embodiment, a method for
treating a tissue site may be described. The method may dispose a
manifold proximate the tissue site and seal the manifold to the
tissue site with a sealing member. The method may fluidly couple a
reduced pressure source to the manifold. The method may further
fluidly couple an ion exchange member having ion exchange media
between the manifold and the reduced pressure source. The method
may fluidly couple an absorbent between the ion exchange member and
the reduced pressure source and supply reduced pressure to the
tissue site to draw fluid from the tissue site to the absorbent
through the ion exchange member. The method may reduce an ionic
concentration of the fluid with the ion exchange member.
[0007] According to another exemplary embodiment, a dressing for
treating a tissue site may be described. The dressing may include
an absorbent adapted to be positioned adjacent the tissue site and
an ion exchange layer adapted to be positioned between the
absorbent and the tissue site. The dressing may include a sealing
member adapted to be positioned over the ion exchange layer and the
absorbent and further adapted to be fluidly sealed to an area
adjacent the tissue site.
[0008] According to another exemplary embodiment, a container for
storing fluids from a tissue site is described. The container may
include a body having an interior portion, a fluid inlet, and a
fluid outlet. The container may also include an absorbent
positioned in the interior and adapted to absorb fluid from the
tissue site. The container may further include an ion exchange
member fluidly coupled to the fluid inlet.
[0009] According to another exemplary embodiment, a tube for
transmitting fluid from a tissue site to a container is described.
The tube may include a cylindrical body having at least one lumen;
and an ion exchange insert disposed within the lumen so that fluid
transmitted through the lumen passes through the ion exchange
member.
[0010] Other aspects, features, and advantages of the exemplary
embodiments will become apparent with reference to the drawings and
detailed description that follow.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is sectional view illustrating a therapy system in
accordance with an exemplary embodiment;
[0012] FIG. 2 is a sectional view illustrating an exemplary
embodiment of a dressing of the therapy system of FIG. 1;
[0013] FIG. 3 is a sectional view illustrating another exemplary
embodiment of the dressing of the therapy system of FIG. 1;
[0014] FIG. 4 is a sectional view illustrating a container of
another exemplary embodiment of the therapy system of FIG. 1;
and
[0015] FIG. 5 is a sectional view illustrating a tube of another
exemplary embodiment of the therapy system of FIG. 1.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0016] New and useful systems, methods, and apparatuses for fluid
storage in a reduced-pressure therapy environment are set forth in
the appended claims. Objectives, advantages, and a preferred mode
of making and using the systems, methods, and apparatuses may be
understood best by reference to the following detailed description
in conjunction with the accompanying drawings. The description
provides information that enables a person skilled in the art to
make and use the claimed subject matter, but may omit certain
details already well-known in the art. Moreover, descriptions of
various alternatives using terms such as "or" do not necessarily
require mutual exclusivity unless clearly required by the context.
The claimed subject matter may also encompass alternative exemplary
embodiments, variations, and equivalents not specifically described
in detail. The following detailed description should therefore be
taken as illustrative and not limiting.
[0017] The exemplary embodiments may be described herein in the
context of reduced-pressure therapy applications, but many of the
features and advantages are readily applicable to other
environments and industries. Spatial relationships between various
elements or to the spatial orientation of various elements may be
described as depicted in the attached drawings. In general, such
relationships or orientations assume a frame of reference
consistent with or relative to a patient in a position to receive
reduced-pressure therapy. 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.
[0018] FIG. 1 is a sectional view of one exemplary embodiment
illustrating a therapy system 100 for supplying reduced pressure to
a tissue site 106 that can reduce the ionic content of fluid before
the fluid contacts an absorbent in accordance with this
specification. In some embodiments, the therapy system 100 may
include a dressing 102 fluidly coupled to a reduced-pressure source
104. A regulator or controller may also be fluidly coupled to the
dressing 102 and the reduced-pressure source 104. The dressing 102
generally may include a drape, such as a drape 108, and a pressure
distribution manifold, such as a manifold 110. In an exemplary
embodiment, the dressing 102 may further include a reduced-pressure
interface, such as a connector 140. The connector 140 is fluidly
coupled to the manifold 110 for distributing reduced pressure at
the tissue site 106. In some embodiments, the dressing 102 may also
include an ion exchange member, such as an ion exchange layer 114,
and an absorbent 116. The absorbent 116 may be disposed between the
manifold 110 and the drape 108. In some exemplary embodiments, the
therapy system 100 may also include a fluid container, such as a
container 112, fluidly coupled to the dressing 102 by a conduit,
such as a tube 120. The container 112 may be further fluidly
coupled to the reduced-pressure source 104 by another conduit, such
as a tube 122.
[0019] In general, components of the therapy system 100 may be
coupled directly or indirectly. For example, reduced-pressure
source 104 may be directly coupled to the container 112 and
indirectly coupled to the dressing 102 through the container 112.
Components may be fluidly coupled to each other to provide a path
for transferring fluids (i.e., liquid and/or gas) between the
components. In some exemplary embodiments, components may be
fluidly coupled with the tube 120 and the tube 122, 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 exemplary 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.
[0020] In operation, the manifold 110 may be placed within, over,
on, or otherwise proximate a tissue site, for example the tissue
site 106. The drape 108 may be placed over the manifold 110 and
sealed to tissue proximate the tissue site 106. The tissue
proximate the tissue site 106 is often undamaged epidermis
peripheral to the tissue site 106. Thus, the dressing 102 can
provide a sealed therapeutic environment proximate the tissue site
106 that may be substantially isolated from the external
environment. The reduced-pressure source 104 can reduce the
pressure in the sealed therapeutic environment. Reduced pressure
applied uniformly through the manifold 110 in the sealed
therapeutic environment can induce macrostrain and microstrain in
the tissue site 106, as well as remove exudates and other fluids
from the tissue site 106, which can be collected in the absorbent
116 or the container 112 and disposed of properly.
[0021] The fluid mechanics of using a reduced-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
reduced-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" reduced pressure, for example.
[0022] 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
reduced-pressure therapy systems herein. Thus, the term
"downstream" typically implies something in a fluid path relatively
closer to a reduced-pressure source, and conversely, the term
"upstream" implies something relatively further away from a
reduced-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, the fluid path may also be
reversed in some applications (such as by substituting a
positive-pressure source for a reduced-pressure source) and this
descriptive convention should not be construed as a limiting
convention.
[0023] 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 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,
reduced pressure may be used in certain tissue areas to grow
additional tissue that may be harvested and transplanted to another
tissue location.
[0024] "Reduced 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 provided
by the dressing 102. In many cases, the local ambient pressure may
also be the atmospheric pressure at which the tissue site 106 is
located. Alternatively, the pressure may be less than a hydrostatic
pressure associated with tissue at the tissue site 106. Unless
otherwise indicated, values of pressure stated herein are gauge
pressures. Similarly, references to increases in reduced pressure
typically refer to a decrease in absolute pressure, while decreases
in reduced pressure typically refer to an increase in absolute
pressure.
[0025] A reduced-pressure source, such as the reduced-pressure
source 104, may be a reservoir of air at a reduced pressure, or may
be a manually 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. The reduced-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 user interfaces that further
facilitate reduced-pressure therapy. While the amount and nature of
reduced pressure applied to a tissue site may vary according to
therapeutic requirements, the pressure typically ranges between -5
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).
[0026] The manifold 110 can be generally adapted to contact the
tissue site 106. The manifold 110 may be partially or fully in
contact with the tissue site 106. If the tissue site 106 extends
into the tissue from a tissue surface, for example, the manifold
110 may partially or completely fill the tissue site 106, or may be
placed over the tissue site 106. The manifold 110 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 the tissue site 106. For
example, the size and shape of the manifold 110 may be adapted to
the contours of deep and irregular shaped tissue sites.
[0027] More generally, a manifold is a substance or structure
adapted to distribute reduced pressure to a tissue site, remove
fluids from a tissue site, or distribute reduced pressure to and
remove fluids from a tissue site. In some exemplary embodiments, a
manifold may also facilitate delivering fluids to a tissue site,
for example, if the fluid path is reversed or a secondary fluid
path is provided. A manifold may include flow channels or pathways
that distribute fluids provided to and removed from a tissue site
around the manifold. In some embodiments, the flow channels or
pathways may be interconnected to improve distribution of fluids
provided to or removed from a tissue site. For example, cellular
foam, open-cell foam, porous tissue collections, and other porous
material, such as gauze or felted mat, generally include structural
elements arranged to form flow channels. Liquids, gels, and other
foams may also include or be cured to include flow channels.
[0028] In some embodiments, the manifold 110 may be a porous foam
material having interconnected cells or pores adapted to uniformly
(or quasi-uniformly) distribute reduced pressure to the tissue site
106. The foam material may be either hydrophobic or hydrophilic. In
one non-limiting example, the manifold 110 can be an open-cell,
reticulated polyurethane foam such as GranuFoam.RTM. dressing
available from Kinetic Concepts, Inc. of San Antonio, Tex.
[0029] In an example in which the manifold 110 may be made from a
hydrophilic material, the manifold 110 may also wick fluid away
from the tissue site 106, while continuing to distribute reduced
pressure to the tissue site 106. The wicking properties of the
manifold 110 may draw fluid away from the tissue site 106 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. (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.
[0030] The manifold 110 may further promote granulation at the
tissue site 106 when pressure within the sealed therapeutic
environment 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 the tissue site 106 when
reduced pressure is applied through the manifold 110 to the tissue
site 106.
[0031] In some embodiments, the manifold may be constructed from
bioresorable 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 manifold 110 may further serve as a scaffold for
new cell-growth, or a scaffold material may be used in conjunction
with the manifold 110 to promote cell-growth. A scaffold is
generally a 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.
[0032] The drape 108 is an example of a sealing member. The sealing
member may be constructed from a material that can provide a fluid
seal between two components or two environments, such as between a
therapeutic environment and a local external environment. The
sealing member may be, for example, an impermeable or
semi-permeable, elastomeric material that can provide a seal
adequate to maintain a reduced pressure at a tissue site for a
given reduced-pressure source. For semi-permeable materials, the
permeability generally should be low enough that a desired reduced
pressure may be maintained. An attachment device may be used to
attach a sealing member to an attachment surface, such as undamaged
epidermis, a gasket, or another sealing member. 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 of, or an entirety of the sealing
member. Other exemplary embodiments of an attachment device may
include a double-sided tape, paste, hydrocolloid, hydrogel,
silicone gel, organogel, or an acrylic adhesive.
[0033] The reduced pressure developed by the reduced-pressure
source 104 may be delivered through the tube 120 to the connector
140. The connector 140 may be a device configured to fluidly couple
the reduced-pressure source 104 to the sealed therapeutic
environment formed by the drape 108. In some exemplary embodiments,
the connector 140 may include a flange portion that couples to the
drape 108 and a port portion that fluidly couples to the tube 120.
The port portion is fluidly sealed to the flange portion and
provides fluid communication through the flange portion so that
connector 140 may cover an aperture in the drape 108 to prevent
fluid communication between the sealed therapeutic environment and
the ambient environment while allowing fluid communication through
the drape 108 between the sealed therapeutic environment and the
tube 120. In some embodiments, the connector 140 may be a
T.R.A.C..RTM. Pad or Sensa T.R.A.C..RTM. Pad available from KCI of
San Antonio, Tex. In other exemplary embodiments, the connector 140
may also be a conduit inserted through the drape 108.
[0034] The container 112 is representative of a container,
canister, pouch, or other storage component that 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 reduced-pressure therapy. Some exemplary
embodiments of the therapy system 100 may not include the container
112; instead, these exemplary embodiments of the therapy system 100
handle fluid storage with the dressing 102 and the absorbent 116 as
described in more detail below.
[0035] The ion exchange layer 114 may be formed of an ion exchange
media (IEM). IEM may be adapted to provide an exchange of ions
between two electrolytes, or between an electrolyte solution and a
complex. An electrolyte may be a compound that ionizes when
dissolved in a suitable ionizing solvent, such as water. An
electrolyte solution may contain a dissolved salt, such as NaCl. A
complex may be an atom or ion having a surrounding array of bound
molecules or anions known as ligands or complexing agents. IEM
works by replacing cations and anions in an electrolyte or an
electrolyte solution as the electrolyte or electrolyte solution
interacts with the IEM. Cations are ions having a net positive
charge, for example, Na+. Cations may be replaced in the
electrolyte or electrolyte solution with hydrogen (H+) ions of the
IEM. Anions are ions having a net negative charge, for example,
Cl-. Anions may be replaced in the electrolyte or electrolyte
solution with hydroxyl (OH-) ions of the IEM. The H+ and OH- ions
may combine in the electrolyte or electrolyte solution to form
water. The IEM is typically in the form of porous beads that are
formed from crosslinked polymers, such as polystyrene, that are
doped or grafted with acidic polymers. An example of an acidic
polymer may include poly(2-acrylamido-2-methyl-1-propanesulfonic
acid) or polyAMPS. The polyAMPS exchange positively charged salt
ions for H+. Another example of an acidic polymer may include
poly(acrylamido-N-propyltrimethylammonium chloride) or polyAPTAC.
The polyAPTAC exchange negatively charged salt ions for OH-.
[0036] The IEM may include a mixture of cation absorbing media and
anion absorbing media to form a mixed bed media that simultaneously
absorbs both anions and cations. Non-limiting examples of the mixed
bed media include Amberlite IRN150 and TMD-8. The IEM may be formed
of ion exchange resins, zeolites, montmorillonite, bentonites,
clay, or soil humus, for example. Ion exchange resins, also known
as ion exchange polymers, are insoluble matrices normally in the
form of small beads fabricated from an organic polymer substrate.
Ion exchange resins may have pores on the surface that trap and
release ions. Ion exchange resins can include crosslinked
polystyrene, for example. Zeolites are microporous, aluminosilicate
minerals. Zeolites have a porous structure that allow cations, such
as Na.sup.+, K.sup.+, Ca.sup.2+, and Mg.sup.2+, for example, to be
accommodated by the zeolite. Common zeolites include analcime,
chabazite, clinoptilolite, heulandite, natrolite, phillipsite, and
stilbite, for example. In addition to the above materials, other
ion exchange media include activated charcoal, both particulate and
in the form of fabrics or non-wovens, for example, and Zorflex,
also known as Chemviron Carbon. Chemviron Carbon may also be known
as 100% activated carbon.
[0037] The absorbent 116 is an example of a material used to hold,
stabilize and/or solidify fluids that may be collected from the
tissue site 106. The absorbent 116 may be positioned in the
dressing 102, in the container 112, and in other places of the
therapy system 100 where fluid absorption may be desired. In some
exemplary embodiments, the absorbent 116 may be formed of a
superabsorbent polymer (SAP). Generally, relative to their mass,
SAPs can absorb and retain large quantities of liquid, and in
particular water. Many medical disposables, such as canisters and
dressings, use SAPs to hold and stabilize or solidify wound fluids.
The SAPs used to form the absorbent 116 may be of the type often
referred to as "hydrogels," "super-absorbents," or "hydrocolloids."
When disposed within the dressing, such as the dressing 102, the
SAPs may be formed into fibers or spheres to manifold reduced
pressure until the SAPs become saturated. Spaces or voids between
the fibers or spheres may allow a reduced pressure that is applied
to the dressing 102 to be transferred within and through the
absorbent 116. In some embodiments, fibers of the absorbent 116 may
be either woven or non-woven.
[0038] The SAPs may be formed in several ways, for example, by gel
polymerization, solution polymerization, or suspension
polymerization. Gel polymerization may involve blending of acrylic
acid, water, cross-linking agents, and ultraviolet (UV) initiator
chemicals. The blended mixture may be placed into a reactor where
the mixture is exposed to UV light to cause crosslinking reactions
that form the SAP. The mixture may be dried and shredded before
subsequent packaging and/or distribution. Solution polymerization
may involve a water based monomer solution that produces a mass of
reactant polymerized gel. The monomer solution may undergo an
exothermic reaction that drives the crosslinking of the monomers.
Following the crosslinking process, the reactant polymer gel may be
chopped, dried, and ground to its final granule size. Suspension
polymerization may involve a water-based reactant suspended in a
hydrocarbon-based solvent. However, the suspension polymerization
process must be tightly controlled and is not often used.
[0039] SAPs absorb liquids by bonding with water molecules through
hydrogen bonding. Hydrogen bonding involves the interaction of a
polar hydrogen atom with an electronegative atom. As a result, SAPs
absorb water based on the ability of the hydrogen atoms in each
water molecule to bond with the hydrophilic polymers of the SAP
having electronegative ionic components. High absorbing SAPs are
formed from ionic crosslinked hydrophilic polymers such as acrylics
and acrylamides in the form of salts or free acids. Because the
SAPs are ionic, they are affected by the soluble ionic components
within the solution being absorbed and will, for example, absorb
less saline than pure water. The lower absorption rate of saline is
caused by the sodium and chloride ions blocking some of the water
absorbing sites on the SAPs. If the fluid being absorbed by the SAP
is a solution containing dissolved mineral ions, fewer hydrogen
atoms of the water molecules in the solution may be free to bond
with the SAP. Thus, the ability of an SAP to absorb and retain a
fluid may be dependent upon the ionic concentration of the fluid
being absorbed. For example, an SAP may absorb and retain
de-ionized water up to 500 times the weight of the dry SAP. In
volumetric terms, an SAP may absorb fluid volumes as high as 30 to
60 times the dry volume of the SAP. Other fluids having a higher
ionic concentration may be absorbed at lower quantities. For
example, an SAP may only absorb and retain a solution that is 0.9%
salt (NaCl) up to 50 times the weight of the dry SAP. Since wound
fluids contain salts, such as sodium, potassium, and calcium, the
absorption capacity of the SAP may be significantly reduced. The
reduction in absorption capacity may necessitate using additional
SAP that can significantly add to the overall bulkiness of the
dressing or fluid storage device. In addition, in many therapy
systems, using additional SAP may not be possible due to size
limitations of the dressing or container. In other therapy systems,
using additional SAP may not be possible because the increase SAP
may decrease the ability of the system to distribute the reduced
pressure through the saturated SAP.
[0040] As disclosed herein, the therapy system 100 can overcome
these shortcomings and others by providing a system that may
include an IEM positioned between the tissue site and an absorbent.
The IEM may reduce the number of ionized particles within the wound
fluid, allowing for greater absorption of the wound fluid by the
SAPs forming the absorbent. For example, in some exemplary
embodiments of the therapy system 100, the IEM may be placed
between the manifold and the absorbent in the dressing so that
wound fluid drawn out of the tissue site passes through an ion
exchange layer before reaching the absorbent. In other exemplary
embodiments, the IEM may be positioned within the tube fluidly
coupling the tissue site and the container that may be filled with
an absorbent formed from SAPs. In another exemplary embodiment, the
IEM may be positioned proximate the fluid inlet of the container.
In general, the IEM may be positioned between the tissue site and
the fluid storage device so that the fluid from the tissue site
passes through the IEM before reaching the absorbent of the fluid
storage device.
[0041] FIG. 2 is a sectional view illustrating additional details
of the dressing 102. The ion exchange layer 114 having IEM may be
positioned between the manifold 110 and the absorbent 116. The ion
exchange layer 114 may be a layer having a first side, a second
side, and a thickness between the first side and the second side.
In some exemplary embodiments, the IEM forming the ion exchange
layer 114, such as, ion exchange resins, may be coated onto a
wicking substrate layer and crosslinked to form the ion exchange
layer 114. Before crosslinking, the ion exchange resins may be
coated onto a fabric or non-woven material. If the ion exchange
resins are coated onto a non-woven material, the resulting ion
exchange layer 114 may be an integral component of the dressing
102. In some embodiments, the ion exchange layer 114 may be formed
around the absorbent 116, enabling ionic components to be removed
before the wound fluid is exposed to the SAP. If the ion exchange
resins are coated onto a fabric, the ion exchange layer 114 may a
non-integral component of the dressing 102. In some embodiments,
the first side of the ion exchange layer 114 may be disposed
adjacent the manifold 110, and the absorbent 116 may be disposed
adjacent the second side of the ion exchange layer 114. The first
side of the ion exchange layer 114 may have a surface area that is
less than the surface area of a side of the manifold 110 that is
adjacent the ion exchange layer 114. In other exemplary
embodiments, the first side of the ion exchange layer 114 may have
a surface area that is equal to or greater than the surface area of
a side of the manifold 110 that is adjacent the ion exchange layer
114. The thickness of the ion exchange layer 114 may depend, in
part, on the expected ionic concentration of the fluids received
from the tissue site 106.
[0042] The absorbent 116 may include a first side, a second side,
and a thickness between the first side and the second side. The
first side of the absorbent 116 may be disposed adjacent the second
side of the ion exchange layer 114. As shown, the first side of the
absorbent 116 may have a surface area that may be substantially
equivalent to the surface area of the second side of the ion
exchange layer 114. In other exemplary embodiments, the surface
area of the first side of the absorbent 116 may be greater than or
less than the surface area of the second side of the ion exchange
layer 114. In some embodiments, the thickness of the absorbent 116
may be greater than the thickness of the ion exchange layer 114. In
other exemplary embodiments, the thickness of the absorbent 116 may
be less than or equal to the thickness of the ion exchange layer
114.
[0043] The drape 108 may be positioned over the absorbent 116
adjacent the second side of the absorbent 116. In some embodiments,
the drape 108 may cover the entirety of the absorbent 116 and the
ion exchange layer 114 and couple to the tissue proximate the
tissue site 106. The connector 140 may be coupled to the drape 108
and fluidly coupled to the absorbent 116 and the manifold 110
through an aperture in the drape 108.
[0044] In operation, reduced pressure may be supplied to the
absorbent 116 and the manifold 110 through the connector 140. The
reduced pressure draws fluids out of the tissue site 106, and the
manifold 110 distributes the fluids from the tissue site 106 to the
ion exchange layer 114. The fluids drawn from the tissue site 106
may have a high ionic concentration. The fluids may pass through
the ion exchange layer 114 where the IEM may reduce the ionic
concentration of the fluid by exchanging cations and anions in the
fluid for H+ and OH- ions in the ion exchange layer 114 before the
fluid moves into the absorbent 116. The fluid passing from the ion
exchange layer 114 into the absorbent 116 may have a reduced ionic
concentration, allowing for increased absorption efficiency by the
absorbent 116. In some exemplary embodiments, the surface area of
the manifold 110 that is adjacent the first side of the ion
exchange layer 114 and the surface area of the absorbent 116 that
is adjacent the second side of the ion exchange layer 114 may be
substantially the same. The equivalent surface areas may increase
the amount of fluid that passes through the ion exchange layer 114
before entering the absorbent 116, which may further increase the
absorption efficiency of the absorbent 116.
[0045] FIG. 3 is a sectional view illustrating additional details
of another exemplary embodiment of the dressing 102. The dressing
102 may include the ion exchange layer 114, the absorbent 116 and a
separate wicking layer 118. The ion exchange layer 114 of FIG. 3
may be formed of beads bound together, for example, by being
sandwiched between two fluid permeable layers, to form a layer
having a first side, a second side, and a thickness between the
first side and the second side. The wicking layer 118 may be a
layer of wicking material configured to draw fluid toward the ion
exchange layer 114. The wicking material may be a material suitable
for disposition adjacent the manifold 110 or the tissue site 106
and configured to draw fluid into and through the material based on
capillary action. In some exemplary embodiments, the wicking
material may be a porous material. In other exemplary embodiments,
the wicking material may be a non-porous material. The exemplary
embodiment of FIG. 3 may operate in a manner similar to the
exemplary embodiment of FIG. 2.
[0046] FIG. 4 is a sectional view illustrating additional details
of the container 112. In some embodiments, the container 112
comprises a body having an interior 124. In some embodiments, an
absorbent 216 may be disposed within the interior 124 of the
container 112. The absorbent 216 may be similar to the absorbent
116 described above with respect to FIGS. 1-3. In some exemplary
embodiments, the absorbent 216 may substantially fill the interior
124. In other exemplary embodiments, the absorbent 216 may fill
only a portion of the interior 124. The interior 124 of the
container 112 may be adapted to allow for the absorbent 216 to
expand if the absorbent 216 absorbs fluid from the tissue site 106.
In some embodiments, the container 112 may be rigid, and the
absorbent 216 may not substantially fill the interior 124, leaving
sufficient space to allow for expansion of the absorbent 216. In
some embodiments, the container 112 may be flexible, and the
interior 124 may be configured to expand to accommodate expansion
of the absorbent 216. In addition, the amount and disposition of
the absorbent 216 within the interior 124 may vary as needed to
allow fluid communication of reduced pressure through the container
112 to the dressing 102.
[0047] The container 112 may further include a fluid inlet 126 and
a fluid outlet 128. In some embodiments, the fluid inlet 126 passes
through a wall of the container 112 to provide fluid communication
between the interior 124 and an area outside of the container 112.
In some embodiments, the tube 120 may fluidly couple to the fluid
inlet 126 so that the fluid inlet 126 may provide fluid
communication between the dressing 102 and the interior 124. The
fluid outlet 128 may extend through a wall of the container 112 to
provide fluid communication between the interior 124 and an area
outside of the container 112. In some embodiments, the tube 122 may
be fluidly coupled to the fluid outlet 128 and may be further
fluidly coupled to the reduced-pressure source 104, allowing for
fluid communication between the reduced-pressure source 104 and the
interior 124. The fluid inlet 126 and the fluid outlet 128 may be
positioned on the container 112 as shown in FIG. 4. In other
embodiments, the fluid inlet 126 and the fluid outlet 128 may be
positioned in other locations to accommodate additional components
of the therapy system 100. For example, the container 112 may be
combined with the reduced-pressure source 104. In this example, the
fluid inlet 126 and the fluid outlet 128 may be disposed on other
portions of the container 112 to accommodate the positioning of
various components of the combined container 112 and
reduced-pressure source 104.
[0048] In some embodiments, the container 112 may include an ion
exchange housing 202. The ion exchange housing 202 may include a
chamber having an inlet fluidly coupled to the tube 120 and an
outlet fluidly coupled to the fluid inlet 126 of the container 112.
An ion exchange member 214 having IEM may be disposed within the
chamber of the ion exchange housing 202. The ion exchange member
214 may be similar to and may include the components of the ion
exchange layer 114 described above with respect to FIGS. 1-3. The
ion exchange member 214 may substantially fill the chamber of the
ion exchange housing 202 so that fluid entering the chamber may
interact with the ion exchange member 214. The ion exchange housing
202 may be coupled adjacent the fluid inlet 126 so that the chamber
of the ion exchange housing 202 is in fluid communication with the
fluid inlet 126. In some exemplary embodiments, a filter 204 may be
positioned in the fluid inlet 126 so that the ion exchange member
214 may not migrate into the interior 124 of the container 112. In
some embodiments, the filter 204 may prevent particulates from the
tissue site 106 from entering the interior 124 of the container
112. The tube 120 may be fluidly coupled to the fluid inlet of the
ion exchange housing 202 so that fluid in the tube 120 may be in
fluid communication with the chamber of the ion exchange housing
202. In other embodiments, the ion exchange housing 202 may be a
separate component or positioned on other portions of the container
112, provided that the fluid communication path between the
dressing 102 and the absorbent 216 passes through the ion exchange
housing 202 and the ion exchange member 214.
[0049] In operation, the reduced-pressure source 104 may supply
reduced pressure to the interior 124 of the container 112 through
the fluid outlet 128 and the tube 122. The reduced pressure may be
communicated through the interior 124 to the fluid inlet 126 and
the tube 120, where the reduced pressure may be further
communicated to the dressing 102 and the tissue site 106. Fluid
passing from the tube 120 into the interior 124 may pass through
the ion exchange member 214. The reduced pressure may draw fluids
out of the tissue site 106 and the manifold 110 may distribute the
fluids from the tissue site 106 to the connector 140 and the tube
120. The fluids drawn from the tissue site 106 may have a high
ionic concentration. The fluids may communicate through the tube
120 into the interior of the ion exchange housing 202, where the
fluids pass through the ion exchange member 214. The ion exchange
member 214 reduces the ionic concentration of the fluid, as
described above, before the fluid passes into the interior 124 of
the container 112. The fluid passing through the ion exchange
member 214 into the interior 124 may have a reduced ionic
concentration, allowing for increased absorption efficiency by the
absorbent 216 disposed within the interior 124.
[0050] FIG. 5 is a sectional view of a tube 220 illustrating
additional details that may be associated with some embodiments.
The tube 220 may be similar to the tube 120 described above. The
tube 220 of FIG. 5 may fluidly couple the dressing 102 to the
container 112 in a manner similar to that of the tube 120 of FIG.
1. The tube 220 may include at least one lumen 222 that may contain
an ion exchange insert 314 having IEM. The ion exchange insert 314
may be similar to the ion exchange layer 114 and the ion exchange
member 214 described above with respect to FIGS. 1-4. The ion
exchange insert 314 may substantially fill the lumen 222. In some
embodiments, the ion exchange insert 314 may permit fluid
communication through the lumen 222 of the tube 220 so that fluid
drawn from the tissue site 106 may be fluidly communicated from the
dressing 102 to the container 112 through the lumen 222 of the tube
220. In some exemplary embodiments, the tube 220 may have multiple
lumens. For example, the tube 220 may have a first lumen
substantially filled with the ion exchange insert 314 and a second
lumen substantially filled with an absorbent. In other exemplary
embodiments, the lumen 222 of the tube 220 may only be partially
filled with the ion exchange insert 314. For example, a portion of
the lumen 222 proximate the manifold 110 may be substantially
filled with the ion exchange insert 314, and another portion of the
lumen 222 proximate the reduced-pressure source 104 may be filled
with an absorbent.
[0051] In operation, the reduced-pressure source 104 may supply
reduced pressure to the container 112 and the tube 220, where the
reduced pressure may be further communicated to the dressing 102
and the tissue site 106. The reduced pressure may draw fluids out
of the tissue site 106 and the manifold 110 may distribute the
fluids from the tissue site 106 to the connector 140 and the tube
220. The fluids drawn from the tissue site 106 may have a high
ionic concentration. As the fluids are communicated through the
tube 220 into the container 112, the fluids may pass through the
ion exchange insert 314. The ion exchange insert 314 may reduce the
ionic concentration of the fluid, as described above, before the
fluid passes into the container 112. The fluid passing across the
ion exchange insert 314 in the lumen 222 of the tube 220 may have a
reduced ionic concentration, allowing for increased absorption
efficiency by an absorbent disposed within the container 112.
[0052] Some exemplary embodiments may include a combination of the
components of FIGS. 2-5. For example, the ion exchange layer 114
may be used with the container 112. In these exemplary embodiments,
the container 112 may include the ion exchange housing 202 or may
not include the ion exchange housing 202. In other embodiments, the
ion exchange layer 114 may be used with the tube 220 and the ion
exchange insert 314. In these exemplary embodiments, the tube 220
may also include an absorbent, or the container 112 may be fluidly
coupled to the tube 220 opposite the manifold 110. In still other
embodiments, the tube 220 having the ion exchange insert 314 may be
used with the container 112 having the ion exchange housing 202 and
the ion exchange member 214. Each exemplary embodiment may be used
with the other disclosed exemplary embodiments provided that the
IEM may be positioned between the manifold 110 and the absorbent
116 or the absorbent 216, for example.
[0053] The systems and methods described herein may provide
significant advantages, some of which have already been mentioned.
For example, the therapy system may include a SAP absorbent in the
dressing having an increased absorbent capacity compared to
standard dressings. The increased absorbent capacity may allow the
amount of SAP used in a dressing or container to be reduced,
enabling a smaller dressing or container to be used. In addition,
using less absorbent provides a potential cost savings over
standard dressings. The systems and methods described herein also
improve the efficiency of the absorbent used in dressings. Less SAP
may be required to form the absorbent for fluid storage. Using less
SAP may enable a low profile dressing to be formed. Using less SAP
may decrease the cost to produce the absorbent and decrease the
cost of other materials, such as drapes or wicking layers, for
example.
[0054] It should be apparent from the foregoing that embodiments
having significant advantages has been provided. While shown in
only a few forms, the systems and methods illustrated are
susceptible to various changes and modifications without departing
from the spirit thereof.
[0055] Although certain illustrative, non-limiting, exemplary
embodiments have been presented, it should be understood that
various changes, substitutions, permutations, and alterations can
be made without departing from the scope the appended claims. It
will be appreciated that any feature that is described in
connection to any one exemplary embodiment may also be applicable
to any other exemplary embodiment.
[0056] It will be understood that the benefits and advantages
described above may relate to one exemplary embodiment or may
relate to several exemplary embodiments. It will further be
understood that reference to "an" item refers to one or more of
those items.
[0057] The steps of the methods described herein may be carried out
in any suitable order, or simultaneously where appropriate.
[0058] Where appropriate, features of any of the exemplary
embodiments described above may be combined with features of any of
the other exemplary embodiments described to form further examples
having comparable or different properties and addressing the same
or different problems.
[0059] It will be understood that the above description of
preferred exemplary embodiments is 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 of
the invention. Although various exemplary embodiments of the
invention have been described above with a certain degree of
particularity, or with reference to one or more individual
exemplary embodiments, those skilled in the art could make numerous
alterations to the disclosed exemplary embodiments without
departing from the scope of the claims.
* * * * *