U.S. patent application number 17/404484 was filed with the patent office on 2021-12-02 for apparatus for irrigation with negative pressure.
The applicant listed for this patent is KCI Licensing, Inc.. Invention is credited to Christopher Brian LOCKE, James A. LUCKEMEYER, Timothy Mark ROBINSON.
Application Number | 20210370043 17/404484 |
Document ID | / |
Family ID | 1000005783105 |
Filed Date | 2021-12-02 |
United States Patent
Application |
20210370043 |
Kind Code |
A1 |
LUCKEMEYER; James A. ; et
al. |
December 2, 2021 |
APPARATUS FOR IRRIGATION WITH NEGATIVE PRESSURE
Abstract
A system is described herein that can irrigate a tissue site
using negative-pressure. The system may include a tissue interface
configured to be placed adjacent to the tissue site, and a sealing
member configured to be placed over the tissue interface to form a
sealed space. The system may also include a negative-pressure
source configured to be fluidly coupled to the sealed space and a
fluid source. The system may further include an irrigation valve.
The irrigation valve can have a fluid inlet configured to be
fluidly coupled to the fluid source. The irrigation valve can also
have a fluid outlet configured to be fluidly coupled to the sealed
space. The irrigation valve may also include a clamp configured to
be actuated by the negative-pressure source to regulate fluid flow
from the fluid source through the fluid outlet.
Inventors: |
LUCKEMEYER; James A.; (San
Antonio, TX) ; 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: |
1000005783105 |
Appl. No.: |
17/404484 |
Filed: |
August 17, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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15580563 |
Dec 7, 2017 |
11123537 |
|
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PCT/US2016/039605 |
Jun 27, 2016 |
|
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17404484 |
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62186116 |
Jun 29, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M 1/90 20210501; A61M
39/227 20130101; F16K 31/1221 20130101; F16K 7/063 20130101; F16K
7/20 20130101; A61M 39/228 20130101; A61M 1/85 20210501; A61M
1/0058 20130101; F16K 7/07 20130101; A61M 39/284 20130101; A61M
1/774 20210501; A61M 1/743 20210501; A61F 13/0206 20130101; A61M
2039/226 20130101 |
International
Class: |
A61M 39/28 20060101
A61M039/28; A61M 39/22 20060101 A61M039/22; F16K 7/07 20060101
F16K007/07; F16K 31/122 20060101 F16K031/122; F16K 7/06 20060101
F16K007/06; F16K 7/20 20060101 F16K007/20; A61M 1/00 20060101
A61M001/00; A61F 13/02 20060101 A61F013/02 |
Claims
1. A system for irrigating a tissue site, comprising: a tissue
interface configured to be placed adjacent to the tissue site; a
sealing member configured to be placed over the tissue interface to
form a sealed space; a negative-pressure source configured to be
fluidly coupled to the sealed space; a fluid source; and an
irrigation valve comprising: a fluid inlet configured to be fluidly
coupled to the fluid source, a fluid outlet configured to be
fluidly coupled to the sealed space, and a clamp actuated by the
negative-pressure source to regulate fluid flow from the fluid
source through the fluid outlet; wherein the clamp comprises: a
fluid enclosure, and a liquid spacer disposed in the fluid
enclosure, wherein the fluid inlet and the fluid outlet are coupled
to the fluid enclosure.
2-11. (canceled)
12. The system of claim 1, wherein the fluid outlet comprises an
orifice configured to provide a maximum flow of about 10 cubic
centimeters per minute.
13. The system of claim 1, wherein: the clamp comprises a pressure
enclosure configured to be fluidly coupled to the negative-pressure
source; the fluid enclosure is disposed in the pressure enclosure
and the fluid inlet and the fluid outlet provide fluid
communication through the pressure enclosure to the fluid
enclosure; and the negative-pressure source is configured to draw
fluid from the pressure enclosure, compressing the pressure
enclosure and the fluid enclosure.
14. The system of claim 13, wherein the fluid enclosure is sized to
provide a flow of about 0.5 cubic centimeters per minute when
compressed by the pressure enclosure.
15. The system of claim 1, wherein the fluid enclosure comprises: a
first sheet; and a second sheet coupled to the first sheet along a
perimeter of the first sheet and the second sheet, the liquid
spacer disposed therein.
16. The system of claim 1, wherein the liquid spacer comprises a
foam block.
17. The system of claim 13, wherein the pressure enclosure
comprises: a first sheet; a second sheet coupled to the first sheet
along a perimeter of the first sheet and the second sheet, the
fluid enclosure disposed therein; and a pressure outlet coupled to
at least one of the first sheet and the second sheet, the pressure
outlet configured to be fluidly coupled to the negative-pressure
source.
18. The system of claim 1, wherein the negative-pressure source
provides negative pressure to the sealed space and the irrigation
valve.
19-32. (canceled)
33. An irrigation valve comprising: a fluid bag configured to be
fluidly coupled between a fluid source and a sealed space; a foam
block encased in the fluid bag; a fluid orifice configured to
couple the fluid bag to the sealed space; and a negative-pressure
bag encasing the fluid bag and configured to be fluidly coupled to
a negative-pressure source.
34. The irrigation valve of claim 33, wherein the fluid bag is
sized to provide a flow of about 10 cubic centimeters per minute at
about -75 mm Hg or less.
35. The irrigation valve of claim 33, wherein the fluid bag is
sized to provide a flow of about 0.5 cubic centimeters per minute
at about -125 mm Hg or less.
36. The irrigation valve of claim 33, wherein the fluid orifice is
configured to provide a maximum flow of about 10 cubic centimeters
per minute.
37. The irrigation valve of claim 33, wherein the fluid bag
comprises: a first sheet; and a second sheet coupled to the first
sheet along a perimeter of the first sheet and the second sheet,
the foam block disposed therein.
38. The irrigation valve of claim 33, wherein the negative-pressure
bag comprises: a first sheet; a second sheet coupled to the first
sheet along a perimeter of the first sheet and the second sheet,
the fluid bag disposed therein; and a pressure outlet coupled to at
least one of the first sheet and the second sheet, the pressure
outlet configured to be fluidly coupled to the negative-pressure
source.
39. A method for irrigating a tissue site, the method comprising:
placing a tissue interface adjacent to the tissue site; covering
the tissue interface and the tissue site to form a sealed space;
fluidly coupling an irrigation valve to the sealed space; fluidly
coupling a fluid source to the irrigation valve; fluidly coupling a
negative-pressure source to the sealed space and the irrigation
valve; operating the negative-pressure source to supply
negative-pressure to the sealed space and the irrigation valve; and
restricting a fluid path through the irrigation valve in response
to a supply of negative pressure; wherein restricting the fluid
path comprises compressing a foam block to restrict fluid paths
through the foam block.
40. The method of claim 39, further comprising: supplying negative
pressure at about 75 mm Hg; and drawing fluid through the fluid
path at about 10 cubic centimeters per minute.
41. The method of claim 39, further comprising: supplying negative
pressure at about 125 mm Hg; and drawing fluid through the fluid
path at about 0.5 cubic centimeters per minute.
42-44. (canceled)
Description
RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 15/580,563, entitled "Apparatus for Irrigation With
Negative Pressure", filed Dec. 7, 2017, which is a National Stage
Entry of International Application No. PCT/US2016/039605, entitled
"Apparatus For Irrigation With Negative Pressure", filed Jun. 27,
2016, which claims the benefit of U.S. Provisional Patent
Application No. 62/186,116, entitled "Apparatus for Irrigation with
Negative Pressure," filed Jun. 29, 2015, all of which are
incorporated herein by reference for all purposes.
TECHNICAL FIELD
[0002] The invention set forth in the appended claims relates
generally to tissue treatment systems and more particularly, but
without limitation, to an apparatus for application of a
therapeutic fluid to tissue using negative pressure.
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] There is also widespread acceptance that cleansing a tissue
site can be highly beneficial for new tissue growth. For example, a
wound can be washed out with a stream of liquid solution, or a
cavity can be washed out using a liquid solution for therapeutic
purposes. These practices are commonly referred to as "irrigation"
and "lavage" respectively.
[0005] While the clinical benefits of negative-pressure therapy and
irrigation are widely known, the cost and complexity of
negative-pressure therapy and irrigation therapy can be a limiting
factor in its application, and the development and operation of
negative-pressure systems, components, and processes and irrigation
therapy systems, components, and processes could benefit
manufacturers, healthcare providers, and patients.
BRIEF SUMMARY
[0006] New and useful systems, apparatuses, and methods for
irrigating a tissue site in a negative-pressure therapy environment
are set forth in the appended claims. Illustrative embodiments are
also provided to enable a person skilled in the art to make and use
the claimed subject matter. For example, a system is described
herein that can irrigate a tissue site using negative-pressure. The
system may include a tissue interface configured to be placed
adjacent to the tissue site, and a sealing member configured to be
placed over the tissue interface to form a sealed space. The system
may also include a negative-pressure source configured to be
fluidly coupled to the sealed space and a fluid source. The system
may further include an irrigation valve. The irrigation valve can
have a fluid inlet configured to be fluidly coupled to the fluid
source. The irrigation valve can also have a fluid outlet
configured to be fluidly coupled to the sealed space. The
irrigation valve may also include a clamp configured to be actuated
by the negative-pressure source to regulate fluid flow from the
fluid source through the fluid outlet.
[0007] Alternatively, other example embodiments describe an
irrigation valve. The irrigation valve can include a jaw configured
to receive a tube, and a piston coupled to the jaw and operable to
move the jaw in response to negative pressure. The piston may be
operable to cycle the jaw between a high-flow position and a
low-flow position to control fluid flow through the tube.
[0008] In another example embodiment, another irrigation valve is
described. The irrigation valve can include a fluid bag configured
to be fluidly coupled between a fluid source and a sealed space and
a foam block encased in the fluid bag. The irrigation valve may
have a fluid orifice configured to couple the fluid bag to the
sealed space. The irrigation valve may also have a
negative-pressure bag encasing the fluid bag and configured to be
fluidly coupled to a negative-pressure source.
[0009] A method for irrigating a tissue site is also described
herein, wherein some example embodiments include placing a tissue
interface adjacent to the tissue site. The tissue interface and the
tissue site can be covered to form a sealed space. An irrigation
valve can be fluidly coupled to the sealed space, and a fluid
source can be fluidly coupled to the irrigation valve. A
negative-pressure source can be fluidly coupled to the sealed space
and the irrigation valve and operated to supply negative-pressure
to the sealed space and the irrigation valve. A fluid path through
the irrigation valve can be restricted in response to the supply of
negative pressure.
[0010] Objectives, advantages, and a preferred mode of making and
using the claimed subject matter may be understood best by
reference to the accompanying drawings in conjunction with the
following detailed description of illustrative embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a schematic diagram of an example embodiment of a
negative-pressure therapy system that can irrigate a tissue site in
accordance with this specification;
[0012] FIG. 2A is a perspective view illustrating additional
details that may be associated with an example embodiment of an
irrigation valve of the negative-pressure therapy system of FIG.
1;
[0013] FIG. 2B is a schematic sectional view illustrating
additional details that may be associated with the irrigation valve
of FIG. 2A in a high-flow position;
[0014] FIG. 2C is a schematic sectional view illustrating
additional details of the irrigation valve of FIG. 2A in a low-flow
position;
[0015] FIG. 3A is a perspective view illustrating additional
details that may be associated with an example embodiment of
another irrigation valve of the negative-pressure therapy system of
FIG. 1;
[0016] FIG. 3B is a schematic sectional view illustrating
additional details of the irrigation valve of FIG. 3A in a
high-flow position;
[0017] FIG. 3C is a schematic assembly view illustrating additional
details of the irrigation valve of FIG. 3A; and
[0018] FIG. 3D is a schematic sectional view illustrating
additional details of the irrigation valve of FIG. 3A in a low-flow
position.
DESCRIPTION OF EXAMPLE EMBODIMENTS
[0019] 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.
[0020] 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 orientations
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.
[0021] FIG. 1 is a schematic diagram of an example embodiment of a
therapy system 100 that can irrigate a tissue site in accordance
with this specification. The therapy system 100 may include a
dressing and a negative-pressure source. For example, a dressing
102 may be fluidly coupled to a negative-pressure source 104, as
illustrated in FIG. 1. In some embodiments, the negative-pressure
source 104 may be fluidly coupled to the dressing 102 through a
fluid interface, such as a connector 106. A dressing generally
includes a cover and a tissue interface. The dressing 102, for
example, may include a cover 108, and a tissue interface 110. The
therapy system 100 may also include a fluid container, such as a
container 112, coupled to the dressing 102 and to the
negative-pressure source 104.
[0022] In some embodiments, the therapy system 100 may provide
irrigation of the tissue site. The therapy system 100 may include a
fluid source and an irrigation valve. For example, the therapy
system 100 may include a fluid source 114 fluidly coupled to an
irrigation valve 116. The irrigation valve 116 may be fluidly
coupled to the dressing 102 through a fluid interface, such as a
connector 118.
[0023] In general, components of the therapy system 100 may be
coupled directly or indirectly. For example, the negative-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.
[0024] In some embodiments, components may be fluidly coupled
through a tube. For example, the negative-pressure source may be
fluidly coupled to the container 112 through a tube 126. The
dressing 102 may be fluidly coupled to the container 112 by a tube
124, and the container 112 may be fluidly coupled to the irrigation
valve 116 by a tube 122. In some embodiments, the irrigation valve
116 may be fluidly coupled to the dressing 102 by a tube 120. A
"tube," as used herein, broadly refers to a tube, pipe, hose,
conduit, or other structure with one or more lumina adapted to
convey a fluid between two ends. Typically, a tube is an elongated,
cylindrical structure with some flexibility, but the geometry and
rigidity may vary. 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.
[0025] In operation, the tissue interface 110 may be placed within,
over, on, or otherwise proximate to a tissue site. The cover 108
may be placed over the tissue interface 110 and sealed to tissue
near the tissue site. For example, the cover 108 may be sealed to
undamaged epidermis peripheral to a tissue site. Thus, the dressing
102 can provide a sealed therapeutic environment proximate to a
tissue site, substantially isolated from the external environment,
and the negative-pressure source 104 can reduce the pressure in the
sealed therapeutic environment. Negative pressure applied across
the tissue site through the tissue interface 110 in the sealed
therapeutic environment can induce macrostrain and microstrain in
the tissue site, as well as remove exudates and other fluids from
the tissue site, which can be collected in container 112 and
disposed of properly.
[0026] The fluid mechanics of using a negative-pressure source to
reduce pressure in another component or location, such as within a
sealed therapeutic environment, can be mathematically complex.
However, the basic principles of fluid mechanics applicable to
negative-pressure therapy 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.
[0027] In general, exudates and other fluids flow toward lower
pressure along a fluid path. Thus, the term "downstream" typically
implies a position in a fluid path relatively closer to a
negative-pressure source, and conversely, the term "upstream"
implies a position 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. This orientation is generally presumed for purposes of
describing various features and components of therapy systems
herein. However, the fluid path may also be reversed in some
applications (such as by substituting a positive-pressure source
for a negative-pressure source or a negative-pressure source for a
fluid source) and this descriptive convention should not be
construed as a limiting convention.
[0028] 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,
negative pressure may be used in certain tissue areas to grow
additional tissue that may be harvested and transplanted to another
tissue location.
[0029] "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 provided
by the dressing 102. In many cases, the local ambient pressure may
also be the atmospheric pressure at which a tissue site is located.
Alternatively, the pressure may be less than a hydrostatic pressure
associated with tissue at the tissue site. Unless otherwise
indicated, values of pressure stated herein are gauge pressures.
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.
[0030] A negative-pressure source, such as the negative-pressure
source 104, 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 user 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 is generally a low vacuum,
also commonly referred to as a rough vacuum, between -5 mm Hg (-667
Pa) and -500 mm Hg (-66.7 kPa). Common therapeutic ranges are
between -75 mm Hg (-9.9 kPa) and -300 mm Hg (-39.9 kPa).
[0031] The tissue interface 110 can be generally adapted to contact
a tissue site. The tissue interface 110 may be partially or fully
in contact with the tissue site. If the tissue site is a wound, for
example, the tissue interface 110 may partially or completely fill
the wound, or may be placed over the wound. The tissue interface
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 a tissue
site. For example, the size and shape of the tissue interface 110
may be adapted to the contours of deep and irregular shaped tissue
sites.
[0032] In some embodiments, the tissue interface 110 may be a
manifold. 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.
[0033] 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.
[0034] In an example in which the tissue interface 110 may be made
from a hydrophilic material, the tissue interface 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
tissue interface 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.
[0035] The tissue interface 110 may further promote granulation at
a tissue site when pressure within the sealed therapeutic
environment is reduced. For example, any or all of the surfaces of
the tissue interface 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 tissue interface
110.
[0036] In some embodiments, the tissue interface 110 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 110 may
further serve as a scaffold for new cell-growth, or a scaffold
material may be used in conjunction with the tissue interface 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.
[0037] In some embodiments, a sealing member, such as the cover 108
may provide a bacterial barrier and protection from physical
trauma. The cover 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 cover 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
cover 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.
[0038] An attachment device may be used to attach the cover 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 cover 108 may be coated with an acrylic
adhesive having a coating weight between about 25 grams per square
meter to about 65 grams per square meter (g.s.m.). Thicker
adhesives, or combinations of adhesives, may be applied in some
embodiments to improve the seal and reduce leaks. Other example
embodiments of an attachment device may include a double-sided
tape, paste, hydrocolloid, hydrogel, silicone gel, or
organogel.
[0039] In some embodiments, the dressing 102 may also include a
fluid interface, such as the connector 106, configured to fluidly
couple the negative-pressure source 104 to the sealed therapeutic
environment formed by the cover 108. In some embodiments, the fluid
interface may include a flange portion that couples to the cover
108 and a portion that fluidly couples to a tube. In one exemplary
embodiment, the fluid interface 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 other exemplary embodiments, a tube may be
inserted through the cover 108. Such a fluid interface can allow
negative pressure to be delivered to the sealed therapeutic
environment. For example, a fluid interface can provide a fluid
conductor through the cover 108 to the tissue interface 110. In
some embodiments, a fluid interface can also provide more than one
fluid path through the cover 108 or merge more than one fluid
conductor into a single fluid path.
[0040] The container 112 is representative of a container,
canister, pouch, or other storage component, which can be used to
manage exudates and other fluids withdrawn from a tissue site. In
many environments, a rigid container may be preferred or required
for collecting, storing, and disposing of fluids. In other
environments, fluids may be properly disposed of without rigid
container storage, and a re-usable container could reduce waste and
costs associated with negative-pressure therapy.
[0041] The fluid source 114 is representative of a container,
canister, pouch, or other fluid storage component, which can be
used to manage an irrigation fluid to be provided to the tissue
site. In some embodiments, the fluid source 114 may be an
intravenous (IV) fluid bag suspended from an intravenous pole. In
other embodiments, the fluid source 114 may be another fluid
storage device positioned proximate to a tissue site. In some
embodiments, the fluid source 114 may be positioned vertically
above the tissue site. In other embodiments, the fluid source 114
may be positioned vertically level or below the tissue site.
[0042] In some embodiments, the dressing 102 may also include a
fluid interface, such as the connector 118, configured to fluidly
couple the irrigation valve 116 to the sealed therapeutic
environment formed by the cover 108. In some embodiments, the fluid
interface may include a flange portion that couples to the cover
108 and a portion that fluidly couples to a tube. In other
exemplary embodiments, a tube may be inserted through the cover
108. Such a fluid interface can allow fluid to be delivered to the
sealed therapeutic environment. For example, a fluid interface can
provide a fluid conductor through the cover 108 to the tissue
interface 110. In some embodiments, a fluid interface can also
provide more than one fluid path through the cover 108 or merge
more than one fluid conductor into a single fluid path.
[0043] Irrigation therapy may provide a continuous or near
continuous supply of fluids to a tissue site. The fluids may flow
across a tissue site and remove undesired products of the healing
process. For example, irrigation therapy may help remove necrotic
tissue, bacteria, exudates, dirt, or other substances from the
tissue site. Generally, saline may be used as an irrigation fluid.
Saline can provide good infection control, and if needed,
additional fluids may be added to the saline or may be provided in
combination with saline to address specific issues of a particular
tissue site.
[0044] Unlike instillation therapy, irrigation therapy does not
include a dwell time; instead, fluids are continually moved across
the tissue site. The continuous movement of fluid can use a large
amount of fluid and can require frequent changing of waste fluid
containers. Irrigation therapy may also require use of dedicated
equipment. Often, the systems for providing irrigation therapy may
not interact well with other therapy systems. For example, an
irrigation therapy system often requires a pump to move irrigation
fluid to and across a tissue site. If the irrigation therapy system
is paired with a negative-pressure therapy system coordination of
multiple pumps may be necessary to prevent over or under
pressurization of the tissue site or other negative interactions
between the pumps. Often a clinician may be required to closely
monitor the operation of both systems to ensure that both therapies
are properly provided. The need for dedicated irrigation therapy
equipment can also prove problematic in mobile situations, such as
in emergency medical vehicles or small trauma centers. There, space
may be at a premium and many users may choose to only provide one
type of therapy device. Consequently, many patients do not receive
beneficial irrigation therapy.
[0045] In some embodiments, the therapy system 100 can provide
negative-pressure therapy to the tissue site. In some embodiments,
the therapy system 100 can also provide irrigation therapy. For
example, the therapy system 100 can be fluidly coupled to the
irrigation valve 116. Operation of the therapy system 100 can
actuate the irrigation valve 116 to draw fluid through the
irrigation valve 116 to the tissue site. By using the therapy
system 100 to actuate irrigation therapy, the rate at which fluids
can be provided to a tissue site may be controlled by the
application of negative-pressure. Furthermore, the irrigation valve
116 can provide irrigation therapy without requiring additional
devices, such as a dedicated irrigation pump.
[0046] FIG. 2A is a perspective view illustrating additional
details that may be associated an irrigation valve 200 that can be
used with some embodiments of the therapy system 100 of FIG. 1. The
irrigation valve 200 may include a clamp 201 operatively coupled to
the tube 120.
[0047] FIG. 2B is a schematic sectional view illustrating
additional details that may be associated with some example
embodiments of an irrigation valve 200 in a first position or a
high-flow position that may be used with some embodiments of the
therapy system 100. The irrigation valve 200 may be an example
embodiment of the irrigation valve 116 of FIG. 1.
[0048] The clamp 201 may include a base 202 having a first plate,
such as a first bar 204, and a second plate, such as a second bar
206. The first bar 204 may be a generally flat member having a
length, width, and thickness. In some embodiments, the length of
the first bar 204 may be greater than a width of the first bar 204
so that the first bar 204 may be rectangular in shape having a
first end and a second end. The thickness of the first bar 204 may
be less than the width of the first bar 204. In other embodiments,
the first bar 204 may have other shapes, for example, square,
circular, triangular, or an amorphous shape. The first bar 204 may
be formed of a material that is relatively rigid, such as metals,
ceramics, or hard plastics. In some embodiments, the first bar 204
may be resistant to deformation in compression and buckling if a
compressive load is applied at the first and second ends of the
first bar 204. For example, if a pressure of about 120 mm Hg is
used to generate a compressive loading at the first and second ends
of the first bar 204, the first bar 204 may deflect, but the first
bar 204 may not suffer a catastrophic failure.
[0049] Similarly, the second bar 206 may be a generally flat member
having a length, width, and thickness. In some embodiments, the
length of the second bar 206 may be greater than a width of the
second bar 206 so that the second bar 206 may be rectangular in
shape having a first end and a second end. The thickness of the
second bar 206 may be less than the width of the second bar 206.
The second bar 206 may be formed of a material that is relatively
rigid, for example metals, ceramics, or hard plastics. The second
bar 206 may be resistant to buckling if a load is applied proximate
to a center of the second bar 206.
[0050] The first bar 204 and the second bar 206 may be coupled at
ends of the first bar 204 and the second bar 206. For example, the
second end of the first bar 204 may be coupled to the first end of
the second bar 206. In some embodiments, the first bar 204 and the
second bar 206 may form an L-shape if coupled together. In other
embodiments, the first bar 204 and the second bar 206 may form a
T-shape. The first bar 204 and the second bar 206 may form an angle
.alpha. if coupled. In some embodiments, the angle .alpha. may be
about 90 degrees. In other embodiments, the angle .alpha. may be
between about 15 degrees and about 165 degrees. The first bar 204
and the second bar 206 may be bonded, welded, adhered, or otherwise
joined. In other embodiments, the first bar 204 and the second bar
206 may be formed of a single piece of material that is formed to
have the angle .alpha..
[0051] In some embodiments, the second bar 206 may have an opening
or an aperture 205. The aperture 205 may be positioned proximate to
the location where the second bar 206 is coupled to the first bar
204. The aperture 205 may extend completely through the second bar
206.
[0052] The clamp 201 may also include a piston 208. The piston 208
may be coupled to the first end of the first bar 204. In some
embodiments, the piston 208 may be located on a side of the first
bar 204. For example, the piston 208 may be located on a same side
of the first bar 204 as the second bar 206. The piston 208 may
include a chamber 210 having a fluid outlet 212. The chamber 210
may be a pressure vessel configured to maintain pressures
substantially different than an ambient pressure. The chamber 210
may have a length that is generally parallel to the length of the
first bar 204. The fluid outlet 212 may be a fluid port fluidly
coupled to the chamber 210. In some embodiments, the fluid outlet
212 may be located on an end of the chamber 210 proximate to the
first end of the first bar 204. In other embodiments, the fluid
outlet 212 may be located elsewhere on the chamber 210. The fluid
outlet 212 may provide a fluid communication path between the
ambient environment and the chamber 210. In some embodiments, the
fluid outlet 212 may be configured to be fluidly coupled to another
device, such as the tube 122. The chamber 210 may have an open end
211 opposite the fluid outlet 212.
[0053] A piston head 214 and a biasing member 216 may be disposed
in the chamber 210. The piston head 214 may be a solid object
configured to fluidly isolate the chamber 210 from the open end
211. In other embodiments, the piston head 214 may have a fluid
path across the piston head 214 from the chamber 210 to the ambient
environment. For example, the piston head 214 may have a valved
passage operable to permit fluid communication across the piston
head 214 if a pressure in the chamber 210 is about or exceeds a
threshold pressure. The piston head 214 may be disposed in the
chamber 210 between the open end 211 and the fluid outlet 212. In
some embodiments, if the chamber 210 is cylindrically-shaped, the
piston head 214 may be a disc having perimeter dimensions so that
the piston head 214 may form a fluid seal with interior surfaces of
the chamber 210. In some embodiments, an o-ring or other sealing
member may fluidly seal the piston head 214 to the chamber 210. The
piston head 214 may be moveable within the chamber 210. In some
embodiments, the piston head 214 can move parallel to a length of
the chamber 210 and the first bar 204 while maintaining the fluid
seal. The piston head 214 may have a first position proximate to
the open end 211 and a second position proximate to the fluid
outlet 212.
[0054] The fluid seal between the piston head 214 and the interior
surfaces of the chamber 210 may permit a differential force to be
developed across the piston head 214. For example, if fluid is
drawn from the chamber 210 through the fluid outlet 212, a pressure
less than an ambient pressure surrounding the piston 208 may be
developed in the chamber 210. The differential pressure between the
ambient pressure and the pressure in the chamber 210 across the
piston head 214 may generate a differential force that urges the
piston head 214 to move toward the fluid outlet 212. Similarly, if
a fluid is forced into the chamber 210 through the fluid outlet
212, a pressure greater than the ambient pressure surrounding the
piston 208 may be developed in the chamber 210. The differential
pressure across the piston head 214 may generate a differential
force that urges the piston head 214 to move away from the fluid
outlet 212.
[0055] Generally, the differential force that can be exerted on the
piston head 214 is proportional to the difference in pressures in
the chamber 210 and the ambient environment and the surface area of
the piston head 214 exposed to the chamber 210. For example, the
size of the piston head 214 may be increased to increase the
potential differential force that can be exerted. Similarly, the
difference between the pressure in the ambient environment and the
pressure in the chamber 210 can be increased to increase the
exerted differential force.
[0056] The biasing member 216 may be disposed in the chamber
between the piston head 214 and the fluid outlet 212. The biasing
member 216 may have a first end proximate to the fluid outlet 212
and a second end proximate to the piston head 214. In some
embodiments, the biasing member 216 may be a spring. As shown in
FIG. 2B, the biasing member 216 may be in a relaxed position.
Generally, a spring, such as the biasing member 216, may exert a
force that is proportional to a distance the spring is moved from a
relaxed position. In some embodiments, the biasing member 216 may
have a length X if the biasing member 216 is in the relaxed
position. The biasing member 216 may bias the piston head 214 away
from the fluid outlet 212 to the first position proximate to the
open end 211.
[0057] The clamp 201 may also include a rod 218. The rod 218 may be
coupled to the piston head 214 on a side that is opposite the
biasing member 216. The rod 218 may be a cylindrical member
extending toward the second bar 206. In other embodiments, the rod
218 may not be cylindrical. The rod 218 may have a perimeter
dimension, such as a diameter, that is less than the perimeter
dimension of the piston head 214 and a length that is less than a
length of the first bar 204. Generally, the rod 218 may be parallel
to the first bar 204.
[0058] The clamp 201 may also include a jaw 220 having a first leg
222, a second leg 224, and a cross leg 226. The first leg 222 may
have a first end coupled to the rod 218 on an opposite end of the
rod 218 from the piston head 214. The first leg 222 may extend
through the aperture 205 of the second bar 206. The first leg 222
may be a rectangular body having a length, width, and thickness.
Generally, the length of the first leg 222 may be greater than a
width or outer diameter of the tube 120. In some embodiments, the
first leg 222 may be a portion of the rod 218 that extends through
the aperture 205 beyond the second bar 206.
[0059] The cross leg 226 may be coupled to an end of the first leg
222 opposite of the rod 218. The cross leg 226 may be parallel to
the second bar 206 and have a length, width, and thickness.
Generally, the length of the cross leg 226 may be greater than a
width or outer diameter of the tube 120. In some embodiments, the
cross leg 226 may have a length such that, the end of the cross leg
226 extends beyond an end of the second bar 206. In other
embodiments, the cross leg 226 may have an end opposite the first
leg 222 that is coextensive with the second end of the second bar
206.
[0060] The second leg 224 may be coupled to an end of the cross leg
226 that is opposite the first leg 222. The second leg 224 may
extend from the cross leg 226 toward the second bar 206. In some
embodiments, the second leg 224 may be parallel to the first leg
222 and have a length such that an end of the second leg 224 that
is opposite the cross leg 226 may extend beyond the end of the
second bar 206. The first leg 222, the second leg 224, the cross
leg 226, and the second bar 206 may form a passageway 228, through
which a tube, such as the tube 120 may be inserted. In other
embodiments, the jaw 220 may be formed with the first leg 222 and
the cross leg 226.
[0061] The tube 120 may be a tube having a tube wall 132 and a
lumen 128. In some embodiments, the tube 120 may also include a
recess 130. A tube is an elongated, cylindrical structure with some
flexibility, but the geometry and rigidity may vary. The tube wall
132 may be formed from a polyurethane, silicone, or other material,
for example. The lumen 128 may be a passage extending a length of
the tube 120 and may be suitable for passage of fluid. In some
embodiments, if a pressure differential of about 75 mm Hg exists
across ends of the lumen 128, the lumen 128 may accommodate a flow
rate of about 10 cubic centimeters a minute. A pressure
differential across the lumen 128 may refer to a difference in
pressures between the pressure at a first end of the lumen 128 and
the pressure at a second end of the lumen 128. The first end of the
lumen 128 may be coupled to a fluid source, such as the fluid
source 114. In some embodiments, the first end of the lumen 128 may
be referred to as a fluid inlet of the irrigation valve 200. The
second end of the lumen 128 may be coupled to the sealed
therapeutic environment, such as through the connector 118. In some
embodiments, the second end of the lumen 128 may be referred to as
a fluid outlet of the irrigation valve 200. The recess 130 may be a
notch or other recess formed in the lumen 128. In some embodiments,
the recess 130 may extend the length of the tube 120. In other
embodiments, the recess 130 may have a length similar to a length
of the second bar 206. In some embodiments, if a pressure
differential of about 125 mm Hg exists across ends of the recess
130, the recess 130 may accommodate a flow rate of about 0.5 cubic
centimeters a minute.
[0062] The fluid outlet 212 may be fluidly coupled to a
negative-pressure source, such as the negative-pressure source 104.
For example, the tube 122 may be coupled to the fluid outlet 212
and the negative-pressure source 104. In some embodiments, the tube
122 may also be fluidly coupled to the connector 106. Similarly,
the tube 120 may be fluidly coupled to the fluid source 114 and the
connector 118. The tube 120 may be passed through the passageway
228. If the recess 130 is less than a length of the tube 120, the
recess 130 may be positioned proximate to the second bar 206.
[0063] The negative-pressure source 104 may be operated to draw
fluid from the sealed therapeutic environment and the chamber 210,
generating a negative pressure in the sealed space and the chamber
210. In some embodiments, the negative-pressure source 104 may
maintain a negative pressure of about 75 mm Hg in the sealed space
and the chamber 210.
[0064] Generally, the biasing member 216 may exert a reactive force
proportional to the distance the biasing member 216 is compressed.
For example, if the second end of the biasing member 216 is moved
toward the first end of the biasing member 216, compressing the
biasing member 216 from the length X to the length X.sub.1, the
biasing member 216 may exert a reactive force that is proportional
to the distance X-X.sub.1, i.e., the amount the biasing member 216
is compressed. In some embodiments, the biasing member 216 may be
selected to compress in response to a particular negative pressure,
or threshold pressure. In some embodiments, the threshold pressure
may be about 75 mm Hg of negative pressure. In other embodiments,
the threshold pressure may be greater than or less than about 75 mm
Hg negative pressure.
[0065] If the differential force exerted by the differential
pressure developed by the removal of fluid by the negative-pressure
source 104 in the chamber 210 is insufficient to overcome the
reactive force of the biasing member 216, the piston head 214 may
remain at the first position illustrated in FIG. 2B. In response,
the rod 218 and the jaw 220 may not move, remaining in a first or
an open position. In the open position, fluid may flow through the
tube 120 from the fluid source 114 to the sealed therapeutic
environment. Generally, the rate of fluid flow may be limited only
by the flow rate that can be accommodated by the lumen 128 at a
pressure differential across the lumen 128. In some embodiments, if
the pressure differential between the sealed space and the ambient
environment is about 75 mm Hg, the flow rate may be about 10 cubic
centimeters a minute through the lumen 128.
[0066] Fluid may flow through the tube 120 to the sealed
therapeutic environment in response to the force of gravity, i.e.,
gravity fed. Fluid flow through the tube 120 may also be aided by
the difference in pressure between the pressure in the sealed
therapeutic environment and the ambient environment. Fluid in the
fluid source 114, fluidly coupled to the sealed therapeutic
environment by the tube 120, may be at the same pressure as the
pressure in the sealed therapeutic environment. If the pressure in
the sealed therapeutic environment is less than the ambient
pressure, such as if the negative-pressure source 104 is operating
to draw fluid from the sealed therapeutic environment, fluid may
move to the sealed therapeutic environment through the irrigation
valve 200.
[0067] FIG. 2C is a schematic sectional view illustrating
additional details of the irrigation valve 200 in a second or
low-flow position. If the negative-pressure source 104 continues to
operate, the negative pressure in the sealed therapeutic
environment and in the chamber 210 may increase. In some
embodiments, the negative-pressure source 104 may operate until the
negative pressure in the sealed therapeutic environment and in the
chamber 210 is about 125 mm Hg. In response, the pressure
differential across the piston head 214 may overcome the reactive
force of the biasing member 216, causing the piston head 214 to
move toward the fluid outlet 212 and compressing the biasing member
216 to the X.sub.1 position. As the piston head 214 moves toward
the fluid outlet 212, the rod 218 can move the jaw 220 toward the
second bar 206 to the low-flow position. The cross leg 226 may
compress the tube 120 against the second bar 206, as shown in FIG.
2C. The force applied to the tube 120 by the cross leg 226 and the
second bar 206 may be proportional to the differential pressure
across the piston head 214 and the surface area of the piston head
214. As the tube 120 is compressed between the jaw 220 and the
second bar 206, the first leg 222 and the second leg 224 may
maintain the position of the tube 120 between the cross leg 226 and
the second bar 206, preventing slippage of the tube 120.
[0068] Compression of the tube 120 by the cross leg 226 may at
least partially compress or block the lumen 128, preventing or
limiting fluid communication through the lumen 128. The recess 130
may remain open. Generally, the rate of fluid flow may be limited
only by the flow rate that can be accommodated by the recess 130 at
the pressure differential across the recess 130. In some
embodiments, if the pressure differential between the sealed space
and the ambient environment is about 125 mm Hg, the flow rate may
be maintained at about 0.5 cubic centimeters per minute through the
recess 130.
[0069] If the negative-pressure source 104 is turned off, the
negative pressure in the chamber 210 and in the sealed space
adjacent to the tissue site may gradually decrease and equalize
with the ambient pressure. In response, the reactive force of the
biasing member 216 may urge the piston head 214 away from the fluid
outlet 212. Similarly, the coupled rod 218 and the jaw 220 may move
from the low-flow position of FIG. 2C to the high-flow position of
FIG. 2B. Movement of the jaw 220 to the high-flow position can open
the lumen 128 of the tube 120 and allow fluid to flow to the sealed
space adjacent to the tissue site at a higher flow rate, for
example, about 10 cubic centimeters per minute.
[0070] In some embodiments, the irrigation valve 200 may be
actuated by the negative-pressure source 104 to provide irrigation
therapy. The negative-pressure source 104 may be turned on and set
to provide an intermittent therapy. The negative-pressure source
104 may remove fluid from the tissue site to develop and maintain
the negative pressure at the tissue site at about 125 mm Hg. During
this time, the negative pressure developed at the tissue site may
be communicated to the chamber 210. In response, the piston head
214 be drawn toward the fluid outlet 212, compressing the biasing
member 216 and the tube 120 with the jaw 220, restricting fluid
flow to the recess 130. Fluid flow through the recess 130 may be
about 0.5 cubic centimeters per minute. In some embodiments, the
negative-pressure source 104 may maintain the negative pressure at
about 125 mm Hg for about 60 minutes, providing about 30 cubic
centimeters (cc) of fluid to the tissue site.
[0071] In some embodiments, the negative-pressure source 104 may
stop developing negative-pressure for about 10 minutes. During this
time period, the negative pressure at the tissue site and the
fluidly coupled chamber 210 may decrease. In response, the biasing
member 216, compressed to the length X.sub.1, may exert a force on
the piston head 214, moving the piston head 214 toward the open end
211 and uncompressing the tube 120 with the jaw 220. Fluid may flow
into the tissue site at about 10 cc/minute, providing about 100 cc
of fluid to the tissue site.
[0072] FIG. 3A is a perspective view illustrating additional
details that may be associated with an irrigation valve 300 that
can be used with some embodiments of the therapy system 100 of FIG.
1. FIG. 3B is a schematic sectional view illustrating additional
details that may be associated with some example embodiments of the
irrigation valve 300 in a high-flow position that may be used with
some embodiments of the therapy system 100. For example, the
irrigation valve 300 may be an example of the irrigation valve 116
of FIG. 1. FIG. 3C is a sectional assembly view of the irrigation
valve 300 illustrating additional details that may be associated
with some embodiments. The irrigation valve 300 may include a fluid
inlet 314, a fluid outlet 316, and a clamp 301. The clamp 301 can
include a fluid bag, such as a fluid enclosure 302, and a
negative-pressure bag, such as a pressure enclosure 304.
[0073] The fluid enclosure 302 may include a liquid spacer or
spacer, such as a foam block 306. The foam block 306 may be a
substance or structure providing a plurality of pathways adapted to
distribute fluid through the fluid enclosure 302. The pathways of
the foam block 306 may be channels interconnected to improve
distribution of fluids across the fluid enclosure 302. 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, the foam block 306 may be a porous
foam material having interconnected cells or pores adapted to
uniformly (or quasi-uniformly) distribute fluid through the fluid
enclosure 302. The foam material may be either hydrophobic or
hydrophilic. In one non-limiting example, the foam block 306 may be
an open-cell, reticulated polyurethane foam such as GranuFoam.RTM.
dressing available from Kinetic Concepts, Inc. of San Antonio,
Tex.
[0074] In some embodiments, the foam block 306 may act as a biasing
member or a spring. For example, foam materials may have an elastic
modulus, which may also be referred to as a foam modulus.
Generally, the elastic modulus of a material may measure the
resistance of the material to elastic deformation under a load. The
elastic modulus of a material may be defined as the slope of a
stress-strain curve in the elastic deformation region of the curve.
The elastic deformation region of a stress-strain curve represents
that portion of the curve where a deformation of a material due to
an applied load is elastic, that is, not permanent. If the load is
removed, the material may return to its pre-loaded state. Stiffer
materials may have a higher elastic modulus, and more compliant
materials may have a lower elastic modulus. Generally, reference to
the elastic modulus of a material refers to a material under
tension.
[0075] For some materials under compression, the elastic modulus
can be compared between materials by comparing the compression
force deflection (CFD) of the materials. Typically, CFD is
determined experimentally by compressing a sample of a material
until the sample is reduced to about 25% of its uncompressed size.
The load applied to reach the 25% compression of the sample is then
divided by the area of the sample over which the load is applied to
arrive at the CFD. The CFD can also be measured by compressing a
sample of a material to about 50% of the sample's uncompressed
size. The CFD of a foam material can be a function of compression
level, polymer stiffness, cell structure, foam density, and cell
pore size.
[0076] Furthermore, CFD can represent the tendency of a foam to
return to its uncompressed state if a load is applied to compress
the foam. For example, a foam having a CFD of about 4 kPa may exert
about 4 kPa in reaction to 25% compression. The CFD of the foam
block 306 may represent the ability of the foam block 306 to
resemble a biasing member, such as a spring. For example, if the
foam block 306 is compressed to 25% of its original size, the foam
block 306 may exert a force that opposes the applied force over the
area of the foam block 306 to which the force is applied. The
reactive force may be proportional to the amount the foam block 306
is compressed.
[0077] Fluid flow through the foam block 306 may be dependent upon
the pore size of the pores within the foam block 306, the stiffness
of the foam block 306, and the area of the foam block 306. For
example, the foam block 306 may permit a higher flow rate through
the foam block 306 if the pores of the foam block 306 are larger
than a foam block 306 having smaller pores. Similarly, if the foam
block 306 is compressed, a foam block 306 having a higher CFD may
permit a higher flow rate than a foam block of comparable size but
having a lower CFD. In some embodiments, if the foam block 306 is
compressed to 25% of its original size, the foam block 306 may
accommodate a fluid flow rate of about 0.5 cubic centimeters per
minute.
[0078] The fluid enclosure 302 may also include a first sheet 308
and a second sheet 310. The first sheet 308 and the second sheet
310 may be positioned on opposite sides of the foam block 306, and
perimeter portions of the first sheet 308 and the second sheet 310
may be coupled to one another to form a chamber 312 having the foam
block 306 disposed therein. In some embodiments, the first sheet
308 and the second sheet 310 may be coupled by welding, bonding, or
adhering, for example. The first sheet 308 and the second sheet 310
may be an elastomeric film or membrane that can provide a seal
adequate to fluidly isolate the foam block 306 from the ambient
environment. In some example embodiments, the first sheet 308 and
the second sheet 310 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. In some embodiments, the first sheet
308 and the second sheet 310 may be a single sheet folded on itself
to form the chamber 312.
[0079] The fluid enclosure 302 may also be coupled to or include
the fluid inlet 314 and the fluid outlet 316. The fluid inlet 314
and the fluid outlet 316 may be fluid couplings or ports. In some
embodiments, the first sheet 308 and the second sheet 310 may be
coupled to the fluid inlet 314 and the fluid outlet 316. Generally,
the fluid inlet 314 and the fluid outlet 316 may provide a fluid
communication path across the first sheet 308 and the second sheet
310 to permit fluid communication with the chamber 312. The fluid
inlet 314 and the fluid outlet 316 can permit the fluid enclosure
302 to be fluidly coupled to both upstream and downstream devices,
such as a sealed space formed by the cover 108 and the fluid source
114. Generally, both the fluid inlet 314 and the fluid outlet 316
may permit fluid flow into and out of the chamber 312.
[0080] In some embodiments, the fluid outlet 316 may be a
calibrated orifice. A calibrated orifice may be a restriction in a
fluid system setting a maximum flow rate for the system. In some
embodiments, the fluid outlet 316 may be calibrated to allow a
maximum flow rate of about 10 cubic centimeters per minute with a
125 mm Hg differential pressure.
[0081] The pressure enclosure 304 may enclose, envelope, or
otherwise contain the fluid enclosure 302. The pressure enclosure
304 may include a first sheet 318 and a second sheet 320.
Furthermore, the first sheet 318 and the second sheet 320 may be
positioned on opposite sides of the fluid enclosure 302, and
perimeter portions of the first sheet 318 and the second sheet 320
may be coupled to one another to form a chamber 322 having the
fluid enclosure 302 disposed therein. In some embodiments, the
first sheet 318 and the second sheet 320 may be coupled by welding,
bonding, or adhering, for example. The first sheet 318 and the
second sheet 320 may be an elastomeric film or membrane that can
provide a seal adequate to fluidly isolate the chamber 322 from the
ambient environment. In some example embodiments, the first sheet
318 and the second sheet 320 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. In some embodiments, the
first sheet 318 and the second sheet 320 may be a single sheet
folded on itself to form the chamber 322. The pressure enclosure
304 may be sealed to the fluid inlet 314 and the fluid outlet 316
so that the chamber 322 may not be in fluid communication with the
ambient environment or with the chamber 312 of the fluid enclosure
302 through the fluid inlet 314 or the fluid outlet 316.
[0082] The pressure enclosure 304 may also include a pressure
outlet 324. The pressure outlet 324 may be a fluid port coupled to
the first sheet 318 or the second sheet 320. The pressure outlet
324 may provide a fluid communication path across the first sheet
318 or the second sheet 320, permitting the chamber 322 of the
pressure enclosure 304 to be fluidly coupled to other devices, such
as the negative-pressure source 104.
[0083] The tube 122 may be coupled to the pressure outlet 324 and
further fluidly coupled to a negative-pressure source, such as the
negative-pressure source 104. The tube 120 may be fluidly coupled
to a fluid source, such as the fluid source 114, and to the fluid
inlet 314. A second tube 120 may be fluidly coupled to the fluid
outlet 316 and then to the connector 118. In some embodiments, the
fluid inlet 314 may be directly coupled to the fluid source 114,
and the tube 120 may be coupled to the fluid outlet 316 and the
connector 118. Fluid may flow from the fluid source 114 through the
chamber 312 of the fluid enclosure 302 and to the tissue site. The
negative-pressure source 104 may be operated to draw fluid from the
sealed space adjacent to the tissue site and through the pressure
outlet 324. Fluid removal from the sealed space may generate a
negative pressure in the sealed therapeutic environment and a
pressure gradient through the tube 120. For example, the pressure
at the tube 120 coupled to the connector 118 may be less than the
pressure at the tube 120 coupled to the fluid source 114. The
pressure gradient through the tube 120 may draw fluid from the
fluid source 114 through the irrigation valve 300 and to the sealed
therapeutic environment.
[0084] As fluid is drawn from the chamber 322 of the pressure
enclosure 304, a differential pressure between the chamber 322 and
the ambient environment may collapse the first sheet 318 and the
second sheet 320 against the fluid enclosure 302. As more fluid is
drawn from the chamber 322, the pressure enclosure 304 may compress
the fluid enclosure 302 and the foam block 306, as shown in FIG.
3D. Generally, the CFD of the foam block 306 may be selected to
prevent collapse of the foam block 306 until a threshold pressure
is developed in the chamber 322 that, if applied over a surface
area of the fluid enclosure 302, may generate a compressive force
on the fluid enclosure 302. In some embodiments, the threshold
pressure may be about 75 mm Hg of negative pressure. Once the
threshold pressure is crossed, the force exerted on the fluid
enclosure 302 by the pressure enclosure 304 may overcome the CFD of
the foam block 306, compressing the foam block 306. In some
embodiments, as the negative pressure in the chamber 322 reaches
about 125 mm Hg, the foam block 306 may be compressed to about 25%
of the original size of the foam block 306. Compression of the foam
block 306 may partially block some of the fluid pathways in the
foam block 306, restricting fluid flow through the fluid enclosure
302. For example, if a negative pressure of about 125 mm Hg is
developed in the chamber 322, the foam block 306 may be compressed
so that the fluid pathways of the foam block 306 permit about 0.5
cubic centimeters per minute of fluid flow through the chamber
312.
[0085] If the negative-pressure source 104 is turned off, the
negative pressure in the chamber 322 and in the sealed space
adjacent to the tissue site may gradually decrease. For example,
leaks in the cover 108 or inflow of fluid from the body into the
sealed therapeutic environment may decrease the negative pressure
in the sealed therapeutic environment. As the pressure begins to
equalize with the ambient pressure, the foam block 306 may expand,
opening the fluid pathways of the foam block 306. Flow may flow
through the irrigation valve 300 to the sealed space adjacent to
the tissue site at the increased flow rate.
[0086] The systems, apparatuses, and methods described herein may
provide significant advantages. For example, the irrigation valve
116 my permit the application of an irrigation fluid to a wound
from a simple, potentially disposable device, using existing vacuum
therapy systems. The irrigation valve may also be used in the home
and in emerging markets with little oversight. The irrigation valve
may also be used with existing negative-pressure therapy system and
devices without requiring a dedicated irrigation therapy pump.
[0087] The irrigation valve 116 can also provide controlled
irrigation in a compact device. For example, the irrigation valve
116 may be lightweight and sized to provide a known fluid flow for
given conditions. A trauma center or emergency vehicle may have
multiple irrigation valves sized to provide different flow rates at
a same negative-pressure so that irrigation can be provided based
on the needs of the tissue site. Furthermore, the irrigation valves
may be made from materials that make disposal cost effective. In
addition, the irrigation valve 116 can provide irrigation of a
tissue site using a volume of fluid that is comparable to
instillation therapy devices.
[0088] The irrigation valve 116 may also be orientation
insensitive. For example, the irrigation valve may operate as
intended regardless of the position of the irrigation valve or the
orientation of the irrigation valve relative to the force of
gravity. In some embodiments, the irrigation valve 116 may be
driven by the negative-pressure source 104. For example, the
negative-pressure source 014 may drive the jaw 220. In some
embodiments, the negative-pressure source 104 may directly drive
the jaw 220. In some embodiments, the negative-pressure source 104
may provide negative pressure to the sealed space adjacent the
tissue site and the irrigation valve 116.
[0089] While shown in a few illustrative embodiments, a person
having ordinary skill in the art will recognize that the systems,
apparatuses, and methods described herein are susceptible to
various changes and modifications. Moreover, descriptions of
various alternatives using terms such as "or" do not require mutual
exclusivity unless clearly required by the context, and the
indefinite articles "a" or "an" do not limit the subject to a
single instance unless clearly required by the context.
[0090] The appended claims set forth novel and inventive aspects of
the subject matter described above, but the claims may also
encompass additional subject matter not specifically recited in
detail. For example, certain features, elements, or aspects may be
omitted from the claims if not necessary to distinguish the novel
and inventive features from what is already known to a person
having ordinary skill in the art. Features, elements, and aspects
described herein may also be combined or replaced by alternative
features serving the same, equivalent, or similar purpose without
departing from the scope of the invention defined by the appended
claims.
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