U.S. patent application number 16/419829 was filed with the patent office on 2019-09-05 for interfaces, systems, and methods for use in reduced pressure tissue treatment.
The applicant listed for this patent is KCI Licensing, Inc.. Invention is credited to Christopher Brian LOCKE.
Application Number | 20190269836 16/419829 |
Document ID | / |
Family ID | 48980332 |
Filed Date | 2019-09-05 |
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United States Patent
Application |
20190269836 |
Kind Code |
A1 |
LOCKE; Christopher Brian |
September 5, 2019 |
INTERFACES, SYSTEMS, AND METHODS FOR USE IN REDUCED PRESSURE TISSUE
TREATMENT
Abstract
Systems and devices for treating a tissue site may include an
interface adapted to provide a reduced pressure to a dressing. The
interface may include a positive-pressure channel for delivering a
positive pressure from a positive-pressure port to a positive
pressure outlet. The positive-pressure channel may include a
constricted portion configured to provide a pressure drop. The
interface may additionally include a reduced-pressure channel
adapted to deliver reduced pressure to the dressing that
substantially corresponds to the pressure drop. The
reduced-pressure channel may be fluidly coupled between the
positive pressure channel and a side of the interface body adapted
to face the dressing. Other systems and devices are disclosed.
Inventors: |
LOCKE; Christopher Brian;
(Bournemouth, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KCI Licensing, Inc. |
San Antonio |
TX |
US |
|
|
Family ID: |
48980332 |
Appl. No.: |
16/419829 |
Filed: |
May 22, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15453510 |
Mar 8, 2017 |
10335522 |
|
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16419829 |
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13955662 |
Jul 31, 2013 |
9623159 |
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15453510 |
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61679282 |
Aug 3, 2012 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M 27/00 20130101;
A61M 1/0092 20140204; A61M 1/0088 20130101; A61M 1/0058 20130101;
A61M 2205/3344 20130101; A61M 2205/7536 20130101; A61M 1/0076
20130101; A61M 2205/3337 20130101; A61M 1/0086 20140204 |
International
Class: |
A61M 1/00 20060101
A61M001/00 |
Claims
1. An interface for treating a tissue site, comprising: a first
side and a second side, the second side of the interface adapted to
face the tissue site; an inlet port positioned proximate the first
side of the interface and adapted to intake ambient gas, the inlet
port comprising a constricted portion having a first diameter at an
upstream end and a second diameter at an opposing downstream end,
wherein the second diameter is smaller than the first diameter, and
wherein the constricted portion is adapted to provide a pressure
drop; a first reduced-pressure channel extending through the
interface from the inlet port to an outlet port positioned
proximate the first side of the interface; and a second
reduced-pressure channel adapted to deliver a reduced pressure to
the tissue site, the second reduced-pressure channel fluidly
coupled between the first reduced-pressure channel and the second
side of the interface, wherein the reduced pressure substantially
corresponds to the pressure drop.
2. The interface of claim 1, further comprising a pressure-sensing
port positioned in the second side of the interface.
3. The interface of claim 1, wherein the second reduced-pressure
channel has a longitudinal dimension extending between the first
reduced-pressure channel and the second side of the interface that
is greater than 15 millimeters.
4. The interface of claim 1, wherein the first reduced-pressure
channel has a longitudinal axis substantially parallel to the
second side of the interface, and wherein the second
reduced-pressure channel is substantially perpendicular to the
first reduced-pressure channel.
5. The interface of claim 1, further comprising a hydrophobic
filter adapted to be positioned between the tissue site and the
first reduced-pressure channel.
6. The interface of claim 1, further comprising a regulating valve
associated with the second reduced-pressure channel that is adapted
to regulate an amount of the reduced pressure being delivered to
the tissue site.
7. The interface of claim 1, wherein the inlet port has a slope of
30 degrees relative to a longitudinal axis of the first
reduced-pressure channel.
Description
RELATED APPLICATION
[0001] This application is a continuation of U.S. patent
application Ser. No. 15/453,510, filed Mar. 8, 2017, which is a
divisional of U.S. patent application Ser. No. 13/955,662, filed
Jul. 31, 2013, which claims the benefit under 35 USC .sctn. 119(e),
of the filing of U.S. Provisional Patent Application No.
61/679,282, filed Aug. 3, 2012, all of which are hereby
incorporated by reference in their entirety.
BACKGROUND
[0002] The present disclosure relates generally to medical
treatment systems, and more particularly, but not by way of
limitation, to interfaces, systems, and methods for use in reduced
pressure tissue treatment.
[0003] Clinical studies and practice have shown that providing a
reduced pressure in proximity to a tissue site augments and
accelerates the growth of new tissue at the tissue site. The
applications of this phenomenon are numerous, but application of
reduced pressure has been particularly successful in treating
wounds. This treatment (frequently referred to in the medical
community as "negative pressure wound therapy," "reduced pressure
therapy," or "vacuum therapy") provides a number of benefits, which
may include faster healing and increased formulation of granulation
tissue.
SUMMARY
[0004] According to an illustrative embodiment, a positive-pressure
wound interface for providing reduced pressure to a
reduced-pressure dressing on a tissue site is presented. The
positive-pressure wound interface includes an interface body having
a first side and a second, tissue-facing side. An inlet is formed
in the interface body that includes a positive-pressure port and a
reduced-pressure-sensing port. The positive-pressure port is
fluidly isolated from the reduced-pressure-sensing port proximate
the inlet. The positive-pressure wound interface further includes a
positive-pressure channel extending though the interface body from
the positive-pressure port to a positive-pressure outlet. The
positive-pressure channel is configured to deliver a positive
pressure through the interface body from the positive-pressure port
downstream to the positive pressure outlet. The positive-pressure
channel includes at least one constricted portion. The
positive-pressure wound interface further includes a
reduced-pressure channel. The reduced-pressure channel includes a
first end and a second, tissue-facing end, such that the first end
of the reduced-pressure channel is fluidly coupled to the
positive-pressure channel and the second, tissue-facing end is
fluidly coupled to a tissue inlet that is proximate a tissue-facing
side of the interface body. The reduced-pressure channel extends
from the positive-pressure channel to the tissue-facing side of the
interface body and is configured to deliver reduced pressure to the
tissue site. The positive-pressure channel is configured to produce
the reduced pressure by a Venturi effect as positive pressure flows
through the positive-pressure channel and past the reduced-pressure
channel. The positive-pressure wound interface also includes a
reduced-pressure-sensing channel that extends from the
reduced-pressure-sensing port to the tissue-facing side of the
interface body.
[0005] In another illustrative embodiment, a system for treating a
tissue site on a patient with reduced pressure includes a manifold
for placing proximate the tissue site. The manifold has a first
side and a second, tissue-facing side and comprises an absorbent
layer for absorbing liquids from the tissue site. The system
further includes a flexible film drape that has a first side and a
second, tissue-facing side for covering the first side of the
manifold to form a sealed space containing the manifold. The
flexible film drape has an aperture formed proximate the first side
of the manifold. The system includes a positive-pressure wound
interface having a first side and a second, tissue-facing side for
positioning over the flexible film drape. The second, tissue-facing
side of the interface is disposed on the flexible film drape
proximate the aperture. The positive-pressure wound interface
includes an interface body having a first side and a second,
tissue-facing side, and an inlet formed in the interface body. The
inlet has a positive-pressure port and a reduced-pressure-sensing
port, such that the positive-pressure port is fluidly isolated from
the reduced-pressure-sensing port proximate the inlet. The
interface further includes a positive-pressure channel that extends
though the interface body from the positive-pressure port to a
positive-pressure outlet. The positive-pressure channel is
configured to deliver a positive pressure through the interface
body from the positive-pressure port downstream to the
positive-pressure outlet. The positive-pressure channel includes at
least one constricted portion. The positive-pressure wound
interface further includes a reduced-pressure channel having a
first end and a second, tissue-facing end, such that the first end
of the reduced-pressure channel is fluidly coupled to the
positive-pressure channel and the second, tissue-facing end is
fluidly coupled to a tissue inlet that is proximate a tissue-facing
side of the interface body. The reduced-pressure channel extends
from the positive-pressure channel to the tissue-facing side of the
interface body and is configured to deliver the reduced pressure to
the tissue site through the aperture in the flexible film drape.
The interface is configured such that the positive-pressure channel
is configured to produce the reduced pressure by a Venturi effect
as positive pressure flows through the positive-pressure channel
and past the reduced-pressure channel. The interface also includes
a reduced-pressure-sensing channel that extends from the
reduced-pressure-sensing port to the tissue-facing side of the
interface body. The system further includes a pressure-sensing unit
fluidly coupled to the reduced-pressure-sensing channel for
measuring a pressure in the reduced-pressure-sensing channel.
[0006] In yet another illustrative embodiment, a system for
treating a tissue site on a patient with reduced pressure includes
a manifold for placing proximate the tissue site. The manifold has
a first side and a second, tissue-facing side. The system further
includes a flexible film drape for covering the first side of the
manifold to form a sealed space containing the manifold. The
flexible film drape has an aperture. The system also includes an
interface having a first side and a second, tissue-facing side for
positioning over the flexible film drape. The second, tissue-facing
side of the interface is disposed on the flexible film drape
proximate the manifold. The interface includes an inlet port formed
in an interface body for allowing intake of an ambient gas. The
inlet port has a first diameter at an upstream end and a second,
smaller diameter at an opposing downstream end. The interface body
further includes a first and second reduced-pressure channel. The
first reduced-pressure channel extends through the interface body
from the inlet port to an outlet port. The second reduced-pressure
channel is fluidly coupled to the first reduced-pressure channel
and extends from the first reduced-pressure channel to the second,
tissue-facing side of the interface. The second reduced-pressure
channel is configured to deliver the reduced pressure to the tissue
site when a fluid is pulled though the inlet port with sufficient
flow rate to produce the reduced pressure by way of a Venturi
effect. The system further includes a reduced-pressure source
fluidly coupled to the outlet port for pulling the fluid through
the first reduced-pressure channel. A pressure-sensing unit is
fluidly coupled to a pressure-sensing port for monitoring pressure
proximate the tissue site.
[0007] In yet another illustrative embodiment, provided is an
interface for providing a reduced pressure to a dressing. The
interface includes an interface body, an inlet, a positive-pressure
channel, a reduced-pressure channel, and a reduced-pressure sensing
channel. The interface body has a first side and a second side, and
the second side of the interface body is adapted to face the
dressing. The inlet is formed proximate the first side of the
interface body, and the inlet has a positive-pressure port and a
reduced-pressure-sensing port. The positive-pressure channel is
adapted to deliver positive pressure. The positive-pressure channel
extends through the interface body from the positive-pressure port
to a positive-pressure outlet proximate the first side of the
interface body. The positive-pressure channel includes a
constricted portion configured to provide a pressure drop. The
reduced-pressure channel is adapted to deliver the reduced pressure
to the dressing. The reduced-pressure channel is fluidly coupled
between the positive-pressure channel and the second side of the
interface body, and the reduced pressure delivered by the
reduced-pressure channel substantially corresponds to the pressure
drop. The reduced-pressure-sensing channel is in fluid
communication between the reduced-pressure-sensing port and the
second side of the interface body.
[0008] In yet another illustrative embodiment, provided is a system
for treating a tissue site with reduced pressure. The system
includes a manifold, a flexible film drape, an interface, a
positive-pressure source, and a pressure sensing unit. The manifold
is for placing proximate the tissue site, and the manifold
comprises an absorbent layer for absorbing liquids from the tissue
site. The flexible film drape is for covering the manifold to form
a sealed space containing the manifold, and the flexible film drape
has an aperture adapted to provide fluid communication with the
sealed space. The interface is adapted to be positioned over the
flexible film drape, and the interface includes an interface body,
an inlet, a positive-pressure channel, a reduced-pressure channel,
and a reduced-pressure sensing channel. The interface body has a
first side and a second side, and the second side is adapted to
face the flexible film drape and to be in fluid communication with
the manifold through the aperture. The inlet is formed proximate
the first side of the interface body, and the inlet has a
positive-pressure port and a reduced-pressure-sensing port. The
positive-pressure port is fluidly isolated from the
reduced-pressure-sensing port proximate the inlet. The
positive-pressure channel is adapted to deliver positive pressure.
The positive pressure channel extends through the interface body
from the positive-pressure port to a positive-pressure outlet
proximate the first side of the interface body. Further, the
positive-pressure channel includes a constricted portion configured
to provide a pressure drop. The reduced-pressure channel is adapted
to deliver a reduced pressure to the manifold. The reduced-pressure
channel is fluidly coupled between the positive-pressure channel
and the second side of the interface body. Further, the reduced
pressure delivered by the reduced-pressure channel substantially
corresponds to the pressure drop. The reduced-pressure-sensing
channel is in fluid communication between the
reduced-pressure-sensing port and the second side of the interface
body. The positive-pressure source is fluidly coupled to the
positive-pressure channel, and the pressure-sensing unit is fluidly
coupled to the reduced-pressure-sensing channel for measuring a
pressure in the reduced-pressure-sensing channel.
[0009] In yet another illustrative embodiment, provided is a system
for treating a tissue site with a reduced pressure. The system
includes a manifold, a flexible film drape, an interface, a
reduced-pressure source, and a pressure-sensing unit. The manifold
is for placing proximate the tissue site, and the manifold has a
first side and a second side. The second side of the manifold is
adapted to face the tissue site. The flexible film drape is for
covering the first side of the manifold to form a sealed space
containing the manifold, and the flexible film drape has an
aperture adapted to provide fluid communication with the sealed
space. The interface is for positioning over the flexible film
drape proximate the aperture, and the interface has a first side
and a second side. The second side of the interface is adapted to
face the tissue site. The interface includes an inlet port, a first
reduced-pressure channel, a second reduced-pressure channel, and a
pressure-sensing port. The inlet port is positioned proximate the
first side of the interface, and is adapted to intake ambient gas.
Further, the inlet port includes a constricted portion having a
first diameter at an upstream end and a second diameter at an
opposing downstream end. The second diameter is smaller than the
first diameter such that the constricted portion is adapted to
provide a pressure drop. The first reduced-pressure channel extends
through the interface from the inlet port to an outlet port
positioned proximate the first side of the interface. The second
reduced-pressure channel is adapted to deliver the reduced pressure
to the tissue site and is fluidly coupled between the first
reduced-pressure channel and the second side of the interface. The
reduced pressure delivered by the second reduced-pressure channel
substantially corresponds to the pressure drop. The
pressure-sensing port is positioned in the second side of the
interface, the reduced-pressure source is fluidly coupled to the
outlet port, and the pressure-sensing unit is fluidly coupled to
the pressure-sensing port for monitoring pressure proximate the
tissue site.
[0010] Other aspects, features, and advantages of the illustrative
embodiments will become apparent with reference to the drawings and
detailed description that follow.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a schematic diagram, with a portion shown in
cross-section, of an illustrative embodiment of a system for
treating a wound on a patient that includes a positive-pressure
wound interface configured to produce reduced pressure at the wound
by a Venturi effect;
[0012] FIG. 2 is a schematic, cross-sectional view of an
illustrative embodiment of the positive-pressure wound interface
shown in FIG. 1;
[0013] FIG. 3 is a schematic, perspective view of an illustrative
embodiment of a portion of a system for treating a wound on a
patient that includes a positive-pressure wound interface and a
Coanda device;
[0014] FIG. 4 is a schematic, perspective view of an illustrative
embodiment of a Coanda device;
[0015] FIG. 5 is a schematic, perspective view, of a portion of the
Coanda device of FIG. 4 shown over a wound; and
[0016] FIG. 6 is a schematic, cross-sectional view of an
illustrative embodiment of a wound interface for use in a system
for treating a wound on a patient that utilizes a Venturi effect to
deliver a reduced pressure to the wound.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0017] In the following detailed description of the illustrative,
non-limiting embodiments, reference is made to the accompanying
drawings that form a part hereof. These embodiments are described
in sufficient detail to enable those skilled in the art to practice
the subject matter of this disclosure. Other embodiments may be
utilized, and logical, structural, mechanical, electrical, and
chemical changes may be made without departing from the scope of
this disclosure. To avoid detail not necessary to enable those
skilled in the art to practice the embodiments described herein,
the description may omit certain information known to those skilled
in the art. The following detailed description is provided without
limitation and with the scope of the illustrative embodiments being
defined by the appended claims.
[0018] Referring to the figures and initially to FIGS. 1-2,
provided is a system 100 for treating a tissue site. The tissue
site may be, for example, a wound 102 on a patient 104. The system
100 may include a positive-pressure wound interface 106 that has an
interface body 108. The interface body 108 may include a
positive-pressure channel 110 and a reduced-pressure channel 112.
The positive-pressure channel 110 may be configured to create a
Venturi effect as positive pressure flows through the
positive-pressure channel 110 and past the reduced-pressure channel
112. In this manner, the interface body 108 may enable the delivery
of reduced pressure to the wound 102 as the positive pressure flows
through the positive-pressure channel 110 and past the
reduced-pressure channel 112.
[0019] The system 100 may further include a wound dressing 114
positioned adjacent the wound 102. The system 100 may work with
many types of dressings, but is shown in FIG. 1, for example, with
the wound dressing 114. The wound dressing 114 includes a wound
filler 113 that may be comprised of a wound-interface layer 116 and
an absorbent layer 118. The wound filler 113 has a first side 115
and a second, tissue-facing side 117. The wound-interface layer 116
may be a manifold, wicking layer, or other material for interfacing
with the wound 102. A manifold refers generally to a substance or
structure that is provided to assist in applying reduced pressure
to, delivering fluids to, or removing fluids from a tissue site,
such as the wound 102. The manifold includes a plurality of flow
channels or pathways that distribute fluids provided to and removed
from the wound 102 around the manifold. In one illustrative
embodiment, the flow channels or pathways are interconnected to
improve distribution of fluids provided to or removed from the
wound 102. The manifold may be a biocompatible material that is
capable of being placed in contact with the wound 102 and
distributing reduced pressure to the wound 102. Examples of
manifolds include, without limitation, one or more of the
following: devices that have structural elements arranged to form
flow channels, such as, for example, cellular foam, open-cell foam,
porous tissue collections, liquids, gels, and foams that include,
or cure to include, flow channels; porous material, such as foam,
gauze, felted mat, or similar material suited to a particular
biological application; porous foam that includes a plurality of
interconnected cells or pores that act as flow channels, such as,
for example, a polyurethane, open-cell, reticulated foam such as
GranuFoam.RTM. material manufactured by Kinetic Concepts,
Incorporated of San Antonio, Tex.; a bioresorbable material; or a
scaffold material.
[0020] The absorbent layer 118 may absorb liquid from the wound
102. The absorbent layer 118 may be any material that retains
liquids and may comprise one or more of the following:
Luquafleece.RTM. material, BASF 402c, Technical Absorbents 2317
available from Technical Absorbents (www.techabsorbents.com),
sodium polyacrylate super absorbers, cellulosics (carboxy methyl
cellulose and salts such as sodium CMC), or alginates. The
absorbent layer 118 may allow fluids and exudate removed from the
wound 102 to be stored within the wound filler 113 instead of
storing the wound fluids remotely in a canister. As will be
described in more detail below, the wound dressing 114 may be
configured to encourage the evaporation of moisture stored within
the wound filler 113 to keep the wound filler 113 from becoming
overly saturated with wound fluid. If the wound filler 113 becomes
overly saturated with fluid, the wound filler 113 may not be able
to absorb additional fluids from the wound 102.
[0021] Continuing with FIGS. 1-2, the wound dressing 114 may
further include a sealing member 120 disposed over the wound filler
113 and a portion of intact skin 122 to form a sealed space 124.
The sealing member 120 may include a first side 130 and a second,
tissue-facing side 132. A treatment aperture 126 may be formed in
the sealing member 120 to provide fluid access to the sealed space
124. The positive-pressure wound interface 106 may be in fluid
communication with the treatment aperture 126.
[0022] The sealing member 120 may be any liquid-impervious material
capable of forming the sealed space 124 into which reduced pressure
may be applied. For example, the sealing member 120 may be formed
from a high-moisture-vapor-transfer-rate material (high MVTR
material) or a drape material that may be a flexible film.
"Moisture Vapor Transmission Rate" or "MVTR" represents the amount
of moisture that can pass through a material in a given period of
time. A high-moisture-vapor-transfer-rate material typically has a
moisture vapor transmission rate greater than 300 g/m.sup.2 per 24
hours, and more typically 1000 g/m.sup.2 per 24 hours or more. The
sealing member 120 allows vapor to egress from the sealed space 124
through the sealing member 120 to the atmosphere exterior to the
wound dressing 114.
[0023] The sealing member 120 may comprise one or more of the
following: hydrophilic polyurethane; cellulosics; hydrophilic
polyamides; an INSPIRE 2301 material from Expopack Advanced
Coatings of Wrexham, United Kingdom; a thin, uncoated polymer
drape; natural rubbers; polyisoprene; styrene butadiene rubber;
chloroprene rubber; polybutadiene; nitrile rubber; butyl rubber;
ethylene propylene rubber; ethylene propylene diene monomer;
chlorosulfonated polyethylene; polysulfide rubber; polyurethane
(PU); EVA film; co-polyester; silicones; silicone drape; a 3M
Tegaderm.RTM. drape; a polyurethane (PU) drape, such as one
available from Avery Dennison Corporation of Pasadena, Calif.;
polyether block polyamide copolymer (PEBAX), for example, from
Arkema, France; or other similar material.
[0024] An attachment device 128, for example, an adhesive, may be
coupled to all or a portion of a second, patient-facing side 132 of
the sealing member 120. The attachment device 128 may attach the
sealing member 120 to the portion of intact skin 122 of the patient
104 and/or a portion of the wound filler 113.
[0025] The performance of the sealing member 120 with respect to
MVTR may be enhanced by only covering a limited surface area of the
second, patient-facing side 132 of the sealing member 120 with the
attachment device 128. For example, only the peripheral edge or
portion of the sealing member 120 may be covered, or a limited
pattern may be used. According to one illustrative embodiment of a
limited pattern, only 30 to 60 percent of the surface area of the
second, patient-facing side 132 may be covered with the attachment
device 128. For example, the attachment device 128 may be applied
on the second, patient-facing side 132 in a limited pattern, such
as, for example, a grid, spaced dots, swirls, or other patterns.
The positive-pressure wound interface 106 may be coupled to the
first side 130 of the sealing member 120 by any of the previously
mentioned coupling techniques, or other similar techniques.
[0026] Continuing with FIGS. 1-2, the system 100 may further
include a positive-pressure source 134 fluidly coupled to the
positive-pressure wound interface 106 such that the
positive-pressure wound interface 106 may receive positive pressure
from the positive-pressure source 134. A positive-pressure conduit
136 may couple the positive-pressure source 134 to the
positive-pressure wound interface 106. The positive-pressure
conduit 136 may be coupled by bonding, tube locks, interference
fit, or other technique to the positive-pressure wound interface
106. Although FIG. 1 illustrates the positive-pressure conduit 136
coupling the positive-pressure wound interface 106 to the
positive-pressure source 134, the positive-pressure source 134 may
be an integral part of the wound dressing 114. Thus, in some
embodiments, the positive-pressure conduit 136 may be optional. The
positive-pressure source 134 may be any device for supplying
positive pressure, such as, for example, a positive-pressure pump.
In specific, non-limiting examples, the positive-pressure source
134 may be a diaphragm pump or a disc-pump. In one embodiment (not
shown), a disc-pump may be positioned adjacent or within the wound
dressing 114. In another embodiment (not shown), the disc-pump may
be an integral part of the wound dressing 114.
[0027] In one embodiment, the positive-pressure source 134 may be
capable of delivering a flow rate between about 0.1 L/Min. to about
4 L/min. In a specific, non-limiting embodiment, the
positive-pressure source 134 may be capable of providing a flow
rate of about 3 L/min when the positive-pressure source 134 is not
connected to the positive-pressure wound interface 106, and a flow
rate of about 1 L/Min. to about 1.5 L/min at 50 mm Hg when the
positive-pressure source 134 is connected to the positive-pressure
wound interface 106. In the above embodiments, the flow rate
provides a fluid speed necessary to obtain the desired reduced
pressure using the Venturi effect.
[0028] The amount and nature of the positive pressure supplied to
the positive-pressure wound interface 106 may vary depending on the
construction of the positive-pressure wound interface 106 and the
desired amount or nature of the reduced pressure being supplied to
the wound 102. The desired reduced pressure supplied to the wound
102 may be between about -5 mm Hg (-667 Pa) to about -500 mm Hg
(-66.7 kPa), and more specifically between about -75 mm Hg (-9.9
kPa) to about -300 mm Hg (-39.9 kPa). The positive pressure may be
supplied continuously or intermittently, causing the reduced
pressure to be applied to the wound 102 either continuously or
intermittently.
[0029] The positive-pressure source 134 may be housed within or
used in conjunction with a pressure sensing unit 138. The
positive-pressure source 134 and the pressure sensing unit 138 may
comprise a therapy unit. The pressure sensing unit 138 may contain
sensors, processing units, alarm indicators, memory, databases,
software, display units, and user interfaces that further
facilitate the application of reduced pressure treatment to the
wound 102. In one example, pressure-detection sensors (not shown)
located in the pressure sensing unit 138 may receive pressure data
from the positive-pressure wound interface 106 via one or more
sensing lumens 140. The sensing lumens 140 may be dedicated to
delivering reduced pressure data to the pressure-detection sensors.
The pressure-detection sensors may communicate with a processing
unit, or controller 142. The controller 142 may monitor and control
the reduced pressure delivered to the wound 102 by controlling, for
example, the flow rate from the positive-pressure source 134.
[0030] Referring now primarily to FIG. 2, but with reference to
FIG. 1, the positive-pressure wound interface 106 has a first side
144 and a second, tissue-facing side 146. The second, tissue-facing
side 146 of the positive-pressure wound interface 106 may be
disposed on the sealing member 120 proximate the treatment aperture
126. As described above, the positive-pressure wound interface 106
may be comprised of the interface body 108. The interface body 108
has a first side 148 and a second, tissue-facing side 150. The
positive-pressure wound interface 106 may be a single, molded piece
made from flexible, stable polymers such as silicones, polyurethane
(PU), rubber, or similar materials. In another embodiment, the
positive-pressure wound interface 106 may be assembled from two
parts, each part being a different material. An inner part may be
comprised of a rigid polymer such as an acrylonitrile butadiene
styrene (ABS) or a polycarbonate acrylonitrile butadiene styrene
(PC/ABS). An outer part may be positioned around a portion of the
inner part. The outer part may be comprised of one of the flexible
polymers described above, such as silicones, PU, or rubber. The
positive-pressure wound interface 106 may be assembled from two
parts as described above to help the positive-pressure wound
interface 106 from deforming under thermal and pressure changes.
Portions of the positive-pressure wound interface 106 subject to
air flow may have surfaces that are smooth and substantially free
of molding inclusions to avoid air turbulences.
[0031] An inlet 152 may be formed within the interface body 108.
The inlet 152 may include a positive-pressure port 154 and a
reduced-pressure-sensing port 156 that are fluidly isolated from
each other at least proximate the inlet 152. The positive-pressure
port 154 may be in fluid communication with, or fluidly coupled to,
the positive-pressure conduit 136. The reduced-pressure-sensing
port 156 may be in fluid communication, with or fluidly coupled to,
the one or more sensing lumens 140 by way of a
reduced-pressure-sensing channel 157.
[0032] The positive-pressure channel 110 extends through the
interface body 108 from the positive-pressure port 154 to a
positive-pressure outlet 160. The positive-pressure channel 110 may
have a longitudinal axis substantially parallel to the surface of
the wound 102, or at an angle to the surface of the wound 102, when
positioned for use. The positive-pressure channel 110 may be
configured to deliver the positive pressure through the interface
body 108 from the positive-pressure port 154 downstream to the
positive-pressure outlet 160. The positive-pressure channel 110 may
have a surface that is smooth and substantially free of molding
inclusions to avoid air turbulences within the positive-pressure
channel 110.
[0033] In another embodiment, the positive-pressure channel 110 may
be in fluid communication with a plurality of positive-pressure
outlets 160 for directing flow circumferentially about the
interface body 108 and over the sealing member 120, as described
further below. In yet another embodiment, the positive-pressure
outlet 160 may be a single outlet, such as a circumferential
outlet, circumscribing the interface body 108 for providing
circumferential flow.
[0034] To utilize the Venturi effect as desired, the
positive-pressure channel 110 may include at least one constricted
portion 162. In a specific, non-limiting embodiment, the at least
one constricted portion 162 may have a slope of approximately 20,
25, 30, or 40 degrees (and any number of degrees thereinbetween)
relative to the longitudinal axis of the positive-pressure channel
110 or the longitudinal axis of the constricted portion 162. The
slope of the at least one constricted portion 162 may be gradual to
avoid air turbulence within the positive-pressure channel 110 for a
given set of operational parameters such as, for example, air flow
velocity and pressures. The positive-pressure channel 110 may be
configured to create a Venturi effect when experiencing sufficient
fluid flow therethrough. The Venturi effect is a jet effect that
results in a reduction in pressure when the velocity of an air flow
increases due to the principles of continuity. When a high flow
fluid, for example air, is subjected to a constriction, the
velocity of the air increases. In order to maintain the principles
of conservation of energy and mass, however, the air pressure must
decrease in response to the increase in velocity. Therefore, the
positive-pressure wound interface 106 as a whole, including the
positive-pressure channel 110, is configured to take advantage of
the Venturi effect to create a reduced pressure that may be applied
to the wound 102 via the reduced-pressure channel 112.
[0035] The at least one constricted portion 162 of the
positive-pressure channel 110 may be cone shaped with a first end
174 having a first diameter, D1, and a second, opposing end 176
having a second diameter, D2, such that the first diameter, D1, is
larger than the second diameter, D2. In a specific, non-limiting
example, the first diameter, D1, may be between about 5 millimeters
to about 10 millimeters (mm), and the second diameter, D2, may be
between about 0.2 mm to about 0.7 mm. The at least one constricted
portion 162 may be formed in any suitable shape capable of inducing
the Venturi effect and minimizing air turbulence within the
positive-pressure wound interface 106, as described above.
[0036] Bernoulli's equation may be used to optimize the
construction of the positive-pressure wound interface 106. For
example, Bernoulli's equation may be used to calculate the pressure
drop for a given construction of the positive-pressure wound
interface 106. The pressure drop may correspond to the amount of
reduced pressure applied to the wound 102. Bernoulli's equation may
be represented as follows: p.sub.1-p.sub.2=p/2(v.sub.2{circumflex
over ( )}2-v.sub.1{circumflex over ( )}2), where p is the density
of the air, v1 may be the velocity of the air as it enters the at
least one constricted portion 162, and v2 may be the velocity of
the air as it exits the at least one constricted portion 162.
Therefore, the configuration of the positive-pressure wound
interface 106 may be modified so that a desired pressure drop,
p1-p2, is reached.
[0037] The reduced-pressure channel 112 may be fluidly coupled to
the positive-pressure channel 110 such that the reduced-pressure
channel 112 is in fluid communication with the positive-pressure
channel 110. The reduced-pressure channel 112 may include a first
end 158 fluidly coupled to the positive-pressure channel 110 and a
second, tissue-facing end 164 fluidly coupled to a tissue inlet
166. The tissue inlet 166 may be proximate the second,
tissue-facing side 150 of the interface body 108. The
reduced-pressure channel 112 may extend from the positive-pressure
channel 110 to the tissue-facing side 150 of the interface body
108. In one embodiment, the reduced-pressure channel 112 may be
coupled to the positive-pressure channel 110 downstream of the at
least one constricted portion 162. In another embodiment, the
reduced-pressure channel 112 may be coupled to the
positive-pressure channel 110 at the at least one constricted
portion 162. In a specific, non-limiting embodiment, the
longitudinal dimension of the reduced-pressure channel 112, which
extends from the positive-pressure channel 110 to the tissue-facing
side 150 of the interface body 108, may be greater than about 15
millimeters (mm). In other non-limiting embodiments, the
longitudinal dimension may be between about 5 mm to about 20 mm.
The reduced-pressure channel 112 may be substantially perpendicular
to the longitudinal axis of the positive-pressure channel 110. The
reduced-pressure channel 112 may be configured to deliver reduced
pressure to the wound 102 when positive pressure is pushed into the
positive-pressure channel 110 and past the reduced-pressure channel
112 at an adequate speed. The reduced-pressure channel 112 may have
a surface that is smooth and substantially free of molding
inclusions to avoid air turbulences within the positive-pressure
wound interface 106.
[0038] The positive-pressure wound interface 106 may be configured
so that air flowing through the positive-pressure channel 110
entrains air, including air from the reduced-pressure channel 112,
that is then vented through the positive-pressure outlet 160. The
positive-pressure outlet 160 may be configured to direct air flow
circumferentially over the first side 130 of the sealing member 120
to enhance the moisture-vapor-transmission rate of the sealing
member 120. As previously mentioned, enhancing the
moisture-vapor-transmission rate may increase the life of the wound
filler 113 by keeping the wound filler 113 from becoming saturated
with wound fluid. In one embodiment, the positive-pressure outlet
160 may be configured to vent directly to the atmosphere. In
another embodiment, one or more ducts 168 (see FIGS. 3-5), which
may include conduits, baffling, or other elements, may be coupled
to the positive-pressure outlet 160 for further directing positive
flow over the first side 130 of the sealing member 120. The one or
more ducts 168 may include or be attached to a Coanda device as
will be described in more detail below with reference to FIGS.
3-5.
[0039] The wound dressing 114 may further comprise a hydrophobic
filter 170 positioned adjacent the tissue inlet 166 for preventing
wound exudate from entering the reduced-pressure channel 112. In
another embodiment, the hydrophobic filter 170 may be fluidly
coupled anywhere in the reduced-pressure channel 112.
[0040] In one embodiment, a regulating valve 172 may be associated
with the reduced pressure channel 112 for regulating the amount of
reduced pressure being supplied to the wound 102 independently of
the air speed in the positive-pressure chamber 110. The regulating
valve 172 may provide pressure regulation at the wound 102 that is
independent of the pressure in the positive-pressure channel
110.
[0041] In another embodiment, the controller 142 may be used to
vary the amount of positive pressure provided by, for example, the
positive pressure source 134, to control the amount of reduced
pressure applied at the wound 102. The controller 142 may receive
feedback from the pressure sensing unit 138 that indicates the
amount of pressure being applied to the wound 102. Based on the
feedback, the controller 142 may signal the positive-pressure
source 134 to vary or modulate the amount of positive pressure
generated by the positive-pressure source 134 so that the reduced
pressure applied to the wound 102 reaches a desired level. Power
provided to the positive-pressure source 134 may be varied or
modulated to vary the amount of positive pressure generated by the
positive pressure source 134. A control valve (not shown) may also
be utilized to vary the amount of positive pressure. The controller
142 may allow the system 100 to operate over a range of desired
reduced pressure levels. The controller 142 may be configured to
operate at a number of preset reduced pressure levels that may be
selected by or provided to a healthcare provider. The controller
142 may improve the efficiency of the positive-pressure source 134
by modulating power to the positive pressure source 134 based on
the desired amount of positive pressure to be generated. In the
instance that a battery is used to power the positive-pressure
source 134, the battery life may be extended in this manner.
[0042] The controller 142 may be coupled to an atmospheric pressure
sensor (not shown). The atmospheric pressure may vary depending on
various elements, including the altitude in which the system 100 is
operating. The effects of variable atmospheric pressure may affect
the performance of the system 100. The atmospheric pressure sensor
may allow the controller 142 to account for variances in the
atmospheric pressure and signal or command the positive-pressure
source 134 accordingly. In other words, the controller 142 may
signal the positive-pressure source 134 to increase or decrease the
pressure output based on variances in atmospheric pressure.
[0043] Referring now primarily to FIGS. 3-5, the system 100
illustrated in FIG. 1 may further include a Coanda device 210
associated with the positive-pressure wound interface 106. The
Coanda device 210 may receive fluid exiting the positive-pressure
wound interface 106 to encourage airflow over the wound dressing
114 for enhancing evaporation of liquids from the wound dressing
114. Among other benefits, enhanced evaporation of liquids from the
wound dressing 114 may allow the wound dressing 114 to process
relatively more fluids. The positive-pressure wound interface 106
and the Coanda device 210 may be associated with one another in
several ways. For example, the positive-pressure wound interface
106 may be coupled to the Coanda device 210, formed integrally with
the Coanda device 210, or placed adjacent to the Coanda device 210.
The Coanda device 210 may be coupled to the positive pressure
outlet 160 of the positive-pressure wound interface 106 by the one
or more ducts 168.
[0044] In other embodiments, other entrainment devices may be used
as the Coanda device 210 to entrain air and direct the air over the
wound dressing 114 to achieve the desired air-flow. These other
entrainment devices, such as, for example, a Conventional Ejector,
may be used to entrain air to create a more voluminous flow based
on the presence of a high pressure flow. The Conventional Ejector
may utilize a primary flow located proximate to an available
secondary air source that is "dragged" by an airfoil shape to have
the effect of an air-multiplier.
[0045] The Coanda device 210 may be a device for entraining air, as
described above, that utilizes the Coanda effect. The Coanda effect
is generally a phenomena in which a flow attaches itself to a
nearby surface and remains attached even as the surface (Coanda
surface) pulls away from the initial direction of the flow. As the
flow curves away, the flow may entrain surrounding fluids and
increase the volume of the flow. The Coanda surface close to the
flow may restrict the entrainment in that region, and as the flow
accelerates to try to balance a momentum transfer, a pressure
differential may develop across the flow that changes or deflects
the direction of the flow closer to the surface. The Coanda effect
is named for Henri Coanda and the concept is described in U.S. Pat.
No. 2,052,869, granted to Coanda.
[0046] Thus, as shown in FIG. 5, the Coanda device 210 creates a
desired airflow as suggested by arrows 240. The Coanda device 210
may be fluidly coupled by the one or more ducts 168 to the
positive-pressure outlet 160 formed in the positive-pressure wound
interface 106. The positive-pressure outlet 160 may supply a
relatively high pressure air to the Coanda device 210. In one
embodiment, the discharge flow rate exiting the positive-pressure
outlet 160 may be approximately 2 L/min or greater. As used herein,
air is intended to cover other working gases that may be used to
help remove moisture. The Coanda device 210 may receive positive
pressure air from the one or more ducts 168 and develop an enhanced
air flow that is delivered from the Coanda device 210 over the
first side 130 of the sealing member 120. As the air moves across
the wound dressing 114, any moisture or vapor on the first side 130
of the sealing member 120 may be removed. This may increase or
maintain a strong relative humidity gradient across the sealing
member 120 that helps remove liquid from the wound dressing 114,
which may enhance the ability of the wound dressing 114 to process
liquids.
[0047] Continuing with FIGS. 3-5, the Coanda device 210 may include
an annular nozzle 246. The annular nozzle 246 may form a central
opening 248. The central opening 248 may surround much of the
interface body 108 and a portion of the interface body 108 may
extend through the central opening 248. The annular nozzle 246 may
have walls 250 that form an interior passage 252. A nozzle opening
254 may be formed on the annular nozzle 246 on a portion in or near
the central opening 248. A portion of the walls 250 may form a
Coanda surface 256 proximate to and downstream from the nozzle
opening 254. The fluid or air exiting the nozzle opening 254 may
entrain additional fluid from the central opening 248 as the air
flow follows the Coanda surface 256. The flow of air from the
nozzle opening 254 plus the entrained air from the central opening
248 may produce a combined fluid flow.
[0048] For the configuration shown in FIG. 5, air may be moved out
of the nozzle opening 254 as suggested by arrows 258. The airflow
may entrain additional air from the central opening 248 as
suggested by arrows 260. The combined fluid flow is suggested by
the arrows 240. Based on the Coanda effect, if a volume V.sub.1 of
air is delivered by the one or more ducts 168 to the Coanda device
210 over a time T, and a volume V.sub.2 of air is delivered through
the central opening 248 of the Coanda device 210 over the time T,
the combined air flow (V.sub.2+V.sub.1) will be enhanced or more
volumuous than the original supply (V.sub.1). The Coanda device 210
may operate as described in various positions, and thus, the
positioning depicted in FIGS. 3-5 may be may be flipped or rotated
for orienting the nozzle opening 254 to discharge air away from a
base portion of the interface body 108 such that air recruited from
the central opening 248 is pulled from proximate the first side 130
of the sealing member 120.
[0049] A number of devices or elements may be used to position the
Coanda device 210 to have a flow clearance 268 between the Coanda
device 210 and the sealing member 120. For example, referring to
FIG. 3, a plurality of rib members 270 may be used to suspend the
annular nozzle 246 of the Coanda device 210 to create the flow
clearance 268.
[0050] Referring now primarily to FIG. 6, presented is a
reduced-pressure wound interface 306 for use with a
reduced-pressure source (not shown). The reduced-pressure source
may be analogous to the positive-pressure source 134, but adapted
to provide reduced-pressure. The reduced-pressure wound interface
306 and the reduced-pressure source may be part of a
reduced-pressure treatment system used to treat a wound with
reduced pressure. The reduced-pressure wound interface 306 may be
analogous in many respects to the positive-pressure wound interface
106 illustrated in FIG. 1. Namely, the reduced-pressure wound
interface 306 may be configured to create a Venturi effect that
develops the reduced pressure at a wound. The reduced-pressure
wound interface 306 may have an interface body 308 that may include
a first reduced-pressure channel 310 and a second reduced-pressure
channel 312. The first reduced-pressure channel 310 may be
configured to create a Venturi effect as air is pulled through the
first reduced-pressure channel 310 and past the second
reduced-pressure channel 312. Air may be pulled through the first
reduced-pressure channel 310 by the reduced-pressure source. The
interface body 308 may enable the delivery of reduced pressure to
the wound as the air flows through the first reduced-pressure
channel 310 and past the second reduced-pressure channel 312.
[0051] A wound dressing 314, analogous to the wound dressing 114 of
FIG. 1, may be positioned adjacent the wound. Similar to the wound
dressing 114, the wound dressing 314 may include a wound filler 313
that may be comprised of a wound-interface layer and an absorbent
layer (not shown). The wound-interface layer may be a manifold as
described above. In one embodiment, the wound filler 313 may be a
manifold only since liquids may be removed directly as described
herein. The wound filler 313 may be covered by a sealing member
320. The sealing member 320 may be formed from a
high-moisture-vapor-transfer-rate material (high MVTR material) or
a drape material that may be a flexible film.
[0052] The amount, nature, or pressure of the air pulled through
the first reduced-pressure channel 310 may vary depending on the
construction of the reduced-pressure wound interface 306, ambient
conditions, and the desired amount of the reduced pressure being
supplied to the wound. The desired reduced pressure supplied to the
wound may be between about -5 mm Hg (-667 Pa) to about -500 mm Hg
(-66.7 kPa), and more specifically between about -75 mm Hg (-9.9
kPa) to about -300 mm Hg (-39.9 kPa). The reduced-pressure source
may cause air to be pulled through the first reduced-pressure
channel 310 either continuously or intermittently, causing the
reduced pressure to be applied to the wound either continuously or
intermittently.
[0053] The reduced-pressure source may be housed with or used in
conjunction with a pressure-sensing unit (not explicitly shown but
analogous to the pressure sensing unit 138 in FIG. 1). The
pressure-sensing unit may be fluidly coupled to a pressure-sensing
port 356 formed in the interface body 308 such that the
pressure-sensing port 356 has an opening adjacent a tissue-facing
side of the interface body 308. The pressure-sensing unit may
receive a pressure sample from the pressure-sensing port 356 for
monitoring pressure at the wound. A controller may be connected to
the sensing unit and the reduced-pressure source. The controller
may send signals or commands to the reduced-pressure source based
on data received from the sensing unit to regulate the amount of
reduced pressure supplied to the wound.
[0054] An inlet port 352 may be formed within the interface body
308. The inlet port 352 may allow the intake of an ambient gas. The
inlet port 352 may be shaped such that the inlet port 352 has a
first diameter, D1, at an upstream end, and a second diameter, D2,
at an opposing, downstream end. The first diameter, D1, may be
larger than the second diameter, D2. In other words, the inlet port
352 may have a constricted portion defined by the first and the
second diameters, D1 and D2. The inlet port 352 may have a slope of
approximately 20, 25, 30, 35, or 40 degrees (and any number of
degrees thereinbetween) relative to a longitudinal axis of the
first reduced-pressure channel 310 or the longitudinal axis of the
constricted portion.
[0055] The first reduced-pressure channel 310 may extend through
the interface body 308 from the inlet port 352 to an outlet port
360. The first reduced-pressure channel 310 may have a longitudinal
axis that is substantially parallel to the surface of the wound, or
at an angle to the surface of the wound, when positioned for use.
The first reduced-pressure channel 310 may be configured to pull
air through the interface body 308 from the inlet port 352
downstream to the outlet port 360. The first reduced-pressure
channel 310 may have a surface that is smooth and substantially
free of molding inclusions to avoid air turbulences within the
first reduced-pressure channel 310.
[0056] The second reduced-pressure channel 312 may be coupled to
the first reduced-pressure channel 310 such that the second
reduced-pressure channel 312 is in fluid communication with the
first reduced-pressure channel 310. The second reduced-pressure
channel 312 may extend from the first reduced-pressure channel 310
to the tissue-facing side of the reduced-pressure wound interface
306. The second reduced-pressure channel 312 may be configured to
deliver reduced pressure to the wound when a fluid or air is pulled
through the inlet port 352 with sufficient flow rate to produce the
reduced pressure at the wound by way of the Venturi effect. In one
embodiment, the second reduced-pressure channel 312 may be coupled
to the first reduced-pressure channel 310 downstream of the
constricted portion. In another embodiment, the second
reduced-pressure channel 312 may be coupled to the first
reduced-pressure channel 310 at the constricted portion. In a
specific, non-limiting embodiment, the longitudinal dimension of
the second reduced-pressure channel 312, which extends from the
first reduced-pressure channel 310 to the tissue-facing side of the
interface body 308, may be greater than 15 millimeters (mm). In
other non-limiting embodiments, the longitudinal dimension may be
between about 5 mm to about 20 mm. The second reduced-pressure
channel 312 may be substantially perpendicular to, or at an angle
to, the longitudinal axis of the first reduced-pressure channel
310. The second reduced-pressure channel 312 may have a surface
that is smooth and substantially free of molding inclusions to
avoid air turbulences within the interface 306.
[0057] The reduced-pressure wound interface 306 may be configured
so that air pulled into the first reduced-pressure channel 310 via
the inlet port 352 entrains air surrounding the sealing member 320.
The air flow caused by the air being pulled into the inlet port 352
may cause air to flow over the sealing member 320 to enhance the
moisture-vapor-transmission rate of the sealing member 320. As
previously mentioned, enhancing the moisture-vapor-transmission
rate may increase the life of the wound filler 313 by keeping the
wound filler 313 from becoming overly saturated with wound
fluid.
[0058] The wound dressing 314 may further comprise a hydrophobic
filter 370 positioned between the wound and the first
reduced-pressure channel 310. In one embodiment, the hydrophobic
filter 370 may be positioned within the second reduced-pressure
channel 312. In another embodiment, no hydrophobic filter may be
used and wound exudate removed from the wound may be pulled through
the first and second reduced-pressure channels 310, 312 and
deposited in a canister (not shown).
[0059] In one embodiment, a regulating valve 372 may be associated
with the second reduced-pressure channel 312 for regulating the
amount of reduced pressure being supplied to the wound. The
regulating valve 372 may provide pressure regulation at the wound
that is independent of the reduced pressure in the first
reduced-pressure channel 310.
[0060] The above description of illustrative embodiments is given
by way of example. Although various embodiments have been described
above with a certain degree of particularity, or with reference to
one or more individual embodiments, modifications may be made by
those skilled in the art without departing from the scope of the
appended claims. Further, the steps of the methods described herein
may be carried out in any suitable order, or simultaneously where
appropriate. Aspects of any of the embodiments described above may
be combined with aspects of any of the other embodiments described
to form further examples having comparable or different properties
and addressing the same or different problems. Thus, the benefits
and advantages described above may relate to one embodiment or may
relate to several embodiments.
* * * * *