U.S. patent application number 12/671995 was filed with the patent office on 2011-08-11 for fluid collection canister including canister top with filter membrane and negative pressure wound therapy systems including same.
This patent application is currently assigned to TYCO HEALTHCARE GROUP LP. Invention is credited to Scott Wudyka.
Application Number | 20110196321 12/671995 |
Document ID | / |
Family ID | 44354281 |
Filed Date | 2011-08-11 |
United States Patent
Application |
20110196321 |
Kind Code |
A1 |
Wudyka; Scott |
August 11, 2011 |
Fluid Collection Canister Including Canister Top with Filter
Membrane and Negative Pressure Wound Therapy Systems Including
Same
Abstract
A fluid collection canister including a chamber to collect
fluids and a canister top disposed over the chamber. The canister
top includes a bottom side facing into the chamber, including first
and second ribs disposed thereon, a filter membrane attached to the
first and second ribs, a first port to communicate with the chamber
and a pressure source external to the chamber, and a second port to
communicate with the chamber and a sensor external to the chamber.
The first port is in fluid communication with a first area, which
is bounded by the filter membrane, the first and second ribs and
the bottom side of the canister top. The second port is in fluid
communication with a second area, which is bounded by the filter
membrane, the second rib and the bottom side of the canister
top.
Inventors: |
Wudyka; Scott; (Marlborough,
MA) |
Assignee: |
TYCO HEALTHCARE GROUP LP
Mansfield
MA
|
Family ID: |
44354281 |
Appl. No.: |
12/671995 |
Filed: |
June 12, 2009 |
PCT Filed: |
June 12, 2009 |
PCT NO: |
PCT/US2009/047137 |
371 Date: |
February 3, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12481617 |
Jun 10, 2009 |
|
|
|
12671995 |
|
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Current U.S.
Class: |
604/319 |
Current CPC
Class: |
A61M 2205/3382 20130101;
A61M 1/0049 20130101; A61M 27/00 20130101; A61M 2205/7536 20130101;
A61M 2205/18 20130101; A61M 1/0031 20130101; A61M 2205/3331
20130101; A61M 1/0052 20140204; A61M 2205/3317 20130101; A61M
1/0088 20130101; A61M 1/0001 20130101 |
Class at
Publication: |
604/319 |
International
Class: |
A61M 1/00 20060101
A61M001/00 |
Claims
1. A fluid collection canister, comprising: a chamber to collect
fluids; a canister top disposed over the chamber, the canister top
including a bottom side facing into the chamber, the bottom side
including first and second ribs disposed thereon; a filter membrane
attached to the first and second ribs, a first port located on the
canister top to communicate with the chamber and a pressure source
external to the chamber; a second port located on the canister top
to communicate with the chamber and a sensor external to the
chamber; and wherein the first port is in fluid communication with
a first area, the first area bounded by the filter membrane, the
first and second ribs and the bottom side of the canister top, and
wherein the second port is in fluid communication with a second
area, the second area bounded by the filter membrane, the second
rib and the bottom side of the canister top.
2. The fluid collection canister of claim 1, wherein the filter
membrane is cut to a profile of the first rib.
3. The fluid collection canister of claim 1, wherein the filter
membrane includes a micro-pore filter membrane.
4. The fluid collection canister of claim 1, wherein the first and
second areas are pneumatically isolated from each other by the
second rib.
5. The fluid collection canister of claim 1, further comprising a
third port to introduce the fluids into the chamber.
6. The fluid collection canister of claim 1, further comprising a
side wall to provide engagement of the canister top with an upper
end of a peripheral wall of the chamber.
7. The fluid collection canister of claim 6, wherein at least a
portion of the first rib is disposed adjacent to the side wall.
8. The fluid collection canister of claim 1, wherein the sensor is
a pressure sensor.
9. A portable negative pressure wound therapy system, comprising: a
dressing assembly for positioning over a wound to apply a negative
pressure to the wound; and a canister assembly including: a control
unit; a vacuum source disposed in the control unit; a pressure
sensor in communication with the control unit; and a collection
canister including: a chamber to collect wound fluids from the
dressing assembly; a canister top disposed over the chamber, the
canister top including a bottom side facing into the chamber, the
bottom side including first and second ribs disposed thereon; an
inlet port in fluid communication with the dressing assembly to
introduce the wound fluids from the dressing assembly into the
chamber; a suction port located on the canister top to communicate
with the chamber and the vacuum source; a pressure sensor port
located on the canister top to communicate with the chamber and the
pressure sensor; and a filter membrane attached to the first and
second ribs, wherein the pressure sensor port is in fluid
communication with a first chamber, the first chamber bounded by
the filter membrane, the first and second ribs and the bottom side
of the canister top, and wherein the suction port is in fluid
communication with a second chamber, the second chamber bounded by
the filter membrane, the second rib and the bottom side of the
canister top.
10. The portable negative pressure wound therapy system of claim 9,
wherein the control unit monitors and controls a negative pressure
within the collection canister.
11. The portable negative pressure wound therapy system of claim 9,
wherein the first and second chambers are pneumatically isolated
from each other by the second rib.
Description
BACKGROUND
[0001] 1. Technical Field
[0002] The present disclosure relates to negative pressure wound
therapy systems and, more particularly, to a fluid collection
canister including a canister top with a filter membrane and
negative pressure wound therapy systems including the same.
[0003] 2. Discussion of Related Art
[0004] Negative pressure therapy, also known as suction or vacuum
therapy, has been used in treating and healing wounds. Treating an
open wound by applying negative pressure, e.g., reduced or
sub-atmospheric pressure, to a localized reservoir over a wound has
been found to assist in closing the wound by increasing blood
circulation at the wound area, stimulating the formation of
granulation tissue and promoting the migration of healthy tissue
over the wound. Negative pressure therapy may also inhibit
bacterial growth by drawing wound fluids from the wound such as
exudate, which may tend to harbor bacteria. Negative pressure
therapy can thus be applied as a healing modality for its
antiseptic and tissue regeneration effects. This technique has
proven effective for treating a variety of wound conditions,
including chronic or healing-resistant wounds and ulcers, and is
also used for other purposes such as post-operative wound care.
[0005] Generally, negative pressure therapy provides for a wound
covering to be positioned over the wound to facilitate suction at
the wound area. A conduit is introduced through the wound covering
to provide fluid communication to an external vacuum source, such
as a hospital vacuum system or a portable vacuum pump. Atmospheric
gas, wound exudate or other fluids may thus be drawn from the
reservoir through the fluid conduit to stimulate healing of the
wound. Generally, a fluid collection canister for collecting fluids
aspirated from the wound is positioned in the suction line between
the wound covering and the vacuum source. Exudate drawn from the
reservoir through the fluid conduit may thus be deposited into the
collection canister.
[0006] During a treatment, vacuum levels within a negative pressure
wound therapy system may be monitored and controlled. There are a
variety of pressure detecting devices such as pressure gages,
switches, transducers and transmitters that can be used for
measuring vacuum levels. A negative pressure wound therapy system
may not function properly when fluid contamination of various
components degrades the capability to accurately measure vacuum
levels in the negative pressure wound therapy system. When the
collection canister is tilted from upright, fluid may occlude a
filter in communication with a pressure detecting device,
preventing accurate measurement of vacuum levels in the negative
pressure wound therapy system. This may cause the negative pressure
wound therapy system to react as if a pneumatic leak is present in
the system and may cause vacuum level within the collection
canister to go uncontrolled, which may result in improper therapy
to the patient.
[0007] A mechanism for preventing overfilling of the collection
canister may prevent fluid contamination of various components of
the negative pressure wound therapy system and help to prevent
spillage or leakage of exudate. During a treatment, the collection
canister may be prevented from overfilling by a hydrophobic filter
at the top of the collection canister that shuts off the air flow
to the vacuum source when the collection canister is full. In
portable negative pressure wound therapy systems, which may be worn
or carried by a patient, there is a likelihood that the apparatus
will shift into various orientations while the patient is
ambulating, allowing exudate to occlude the filter when the
collection canister is not full. Negative pressure therapy may be
discontinued or interrupted inadvertently when the filter is
occluded during patient ambulation or when the collection canister
is tipped over. There is a need for a negative pressure wound
therapy system that permits accurate measurement of vacuum levels
in the negative pressure wound therapy system and is capable of
providing negative pressure therapy for varied orientations of the
collection canister.
SUMMARY
[0008] The present disclosure relates to a fluid collection
canister including a chamber to collect fluids and a canister top
disposed over the chamber. The canister top includes a bottom side
facing into the chamber, including first and second ribs disposed
thereon, a filter membrane attached to the first and second ribs, a
first port to communicate with the chamber and a pressure source
external to the chamber, and a second port to communicate with the
chamber and a sensor external to the chamber. The first port is in
fluid communication with a first area, which is bounded by the
filter membrane, the first and second ribs and the bottom side of
the canister top. The second port is in fluid communication with a
second area, which is bounded by the filter membrane, the second
rib and the bottom side of the canister top.
[0009] The present disclosure also relates to a portable negative
pressure wound therapy apparatus including a dressing assembly for
positioning over a wound to apply a negative pressure to the wound
and a canister assembly in fluid communication with the dressing
assembly. The canister assembly includes a control unit, a vacuum
source disposed in the control unit, a pressure sensor in
communication with the control unit, and a collection canister. The
collection canister includes a chamber to collect wound fluids from
the dressing assembly, a canister top disposed over the chamber,
the canister top including a bottom side facing into the chamber,
the bottom side including first and second ribs disposed thereon,
an inlet port in fluid communication with the dressing assembly to
introduce the wound fluids from the dressing assembly into the
chamber, a suction port located on the canister top to communicate
with the chamber and the vacuum source, a pressure sensor port
located on the canister top to communicate with the chamber and the
pressure sensor, and a filter membrane attached to the first and
second ribs. The pressure sensor port is in fluid communication
with a first chamber, which is bounded by the filter membrane, the
first and second ribs and the bottom side of the canister top. The
suction port is in fluid communication with a second chamber, which
is bounded by the filter membrane, the second rib and the bottom
side of the canister top.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Objects and features of the presently disclosed negative
pressure wound therapy systems will become apparent to those of
ordinary skill in the art when descriptions of various embodiments
thereof are read with reference to the accompanying drawings, of
which:
[0011] FIG. 1 is a schematic diagram of an embodiment of a negative
pressure wound therapy system in accordance with the present
disclosure;
[0012] FIG. 2 is a schematic diagram of an embodiment of a negative
pressure wound therapy system including a canister assembly in
accordance with the present disclosure;
[0013] FIG. 3 is a schematic diagram of the canister assembly of
the negative pressure wound therapy system illustrated in FIG.
2;
[0014] FIG. 4 is a cross-sectional view of the collection canister
of the canister assembly shown in FIG. 2 taken along the lines
4-4;
[0015] FIG. 5 is a bottom view of the canister top of the
collection canister shown in FIG. 4;
[0016] FIG. 6 is a schematic diagram of another embodiment of a
canister top of a collection canister in accordance with the
present disclosure;
[0017] FIG. 7 is a schematic diagram of the canister top
illustrated in FIG. 6, shown with a filter membrane, in accordance
with the present disclosure;
[0018] FIG. 8 is a schematic diagram of the canister top
illustrated in FIG. 7 with the outer sealing rib and the isolating
rib of FIG. 6 shown in phantom;
[0019] FIG. 9 is a cross-sectional view of another embodiment of a
collection canister in accordance with the present disclosure;
[0020] FIG. 10 a bottom view of the canister top of the collection
canister shown in FIG. 9;
[0021] FIG. 11 is a schematic diagram of the canister top
illustrated in FIG. 10, shown with a filter membrane, in accordance
with the present disclosure; and
[0022] FIG. 12 is a schematic diagram of the canister top
illustrated in FIG. 11 with the outer sealing rib and the isolating
rib of FIG. 10 shown in phantom.
DETAILED DESCRIPTION
[0023] Various embodiments of the present disclosure provide
negative pressure wound therapy systems (or apparatus) including a
collection canister having a chamber to collect wound fluids and a
canister top disposed over the chamber. Embodiments of the
presently disclosed negative pressure wound therapy systems are
generally suitable for use in applying negative pressure to a wound
to facilitate healing of the wound in accordance with various
treatment modalities. Embodiments of the presently disclosed
negative pressure wound therapy systems are entirely portable and
may be worn or carried by the user such that the user may be
completely ambulatory during the therapy period. Embodiments of the
presently disclosed negative pressure wound therapy apparatus and
components thereof may be entirely reusable or may be entirely
disposable after a predetermined period of use or may be
individually disposable whereby some of the components are reused
for a subsequent therapy application. Embodiments of the presently
disclosed collection canisters interface with a control unit to
allow suction from a vacuum source and to allow monitoring of the
canister vacuum level.
[0024] Hereinafter, embodiments of the presently disclosed negative
pressure wound therapy systems will be described with reference to
the accompanying drawings. Like reference numerals may refer to
similar or identical elements throughout the description of the
figures. As it is used in this description, "wound exudate", or,
simply, "exudate", generally refers to any fluid output from a
wound, e.g., blood, serum, and/or pus, etc. As it is used in this
description, "fluid" generally refers to a liquid, a gas or both.
As it is used in this description, "pressure" generally refers to
positive pressure, negative pressure or both. As it is used in this
description, "pressure" is measured relative to the ambient
atmospheric pressure. Thus, positive pressure refers to pressure
greater than the ambient atmospheric pressure, and negative
pressure (or vacuum) refers to pressure less than the ambient
atmospheric pressure. As used herein, "transmission line" generally
refers to any transmission medium that can be used for the
propagation of signals from one point to another.
[0025] Referring to FIG. 1, a negative pressure wound therapy
apparatus according to an embodiment of the present disclosure is
depicted generally as 10 for use on a wound bed "w" surrounded by
healthy skin "s". Negative pressure wound therapy apparatus 10
includes a wound dressing 12 positioned relative to the wound bed
"w" to define a vacuum chamber 14 about the wound bed "w" to
maintain negative pressure at the wound area. Wound dressing 12
includes a contact layer 18, a wound filler 20 and a wound cover
24.
[0026] Contact layer 18 is intended for placement within the wound
bed "w" and may be relatively non-supportive or flexible to
substantially conform to the topography of the wound bed "w". A
variety of materials may be used for the contact layer 18. Contact
layer 18 selection may depend on various factors such as the
patient's condition, the condition of the periwound skin, the
amount of exudate and/or the condition of the wound bed "w".
Contact layer 18 may be formed from perforated film material. The
porous characteristic of the contact layer 18 permits exudate to
pass from the wound bed "w" through the contact layer 18. Passage
of wound exudate through the contact layer 18 may be substantially
unidirectional such that exudate does not tend to flow back into
the wound bed "w". Unidirectional flow may be encouraged by
directional apertures, e.g., apertures positioned at peaks of
undulations or cone-shaped formations protruding from the contact
layer 18. Unidirectional flow may also be encouraged by laminating
the contact layer 18 with materials having absorption properties
differing from those of the contact layer 18, or by selection of
materials that promote directional flow. A non-adherent material
may be selected for forming the contact layer 18 such that the
contact layer 18 does not tend to cling to the wound bed "w" or
surrounding tissue when it is removed. One example of a material
that may be suitable for use as a contact layer 18 is commercially
available under the trademark XEROFLOW.RTM. offered by Tyco
Healthcare Group LP (d/b/a Covidien). Another example of a material
that may be suitable for use as the contact layer 18 is the
commercially available CURITY.RTM. non-adherent dressing offered by
Tyco Healthcare Group LP (d/b/a Covidien).
[0027] Wound filler 20 is positioned in the wound bed "w" over the
contact layer 18 and is intended to transfer wound exudate. Wound
filler 20 is conformable to assume the shape of any wound bed "w"
and may be packed up to any level, e.g., up to the level of healthy
skin "s" or to overfill the wound such that wound filler 20
protrudes over healthy skin "s". Wound filler 20 may be treated
with agents such as polyhexamethylene biguanide (PHMB) to decrease
the incidence of infection and/or other medicaments to promote
wound healing. A variety of materials may be used for the wound
filler 20. An example of a material that may be suitable for use as
the wound filler 20 is the antimicrobial dressing commercially
available under the trademark KERLIX.TM. AMD.TM. offered by Tyco
Healthcare Group LP (d/b/a Covidien).
[0028] Cover layer 24 may be formed of a flexible membrane, e.g., a
polymeric or elastomeric film, which may include a biocompatible
adhesive on at least a portion of the cover layer 24, e.g., at the
periphery 26 of the cover layer 24. Alternately, the cover layer 24
may be a substantially rigid member. Cover layer 24 may be
positioned over the wound bed "w" such that a substantially
continuous band of a biocompatible adhesive at the periphery 26 of
the cover layer 24 forms a substantially fluid-tight seal with the
surrounding skin "s". An example of a material that may be suitable
for use as the cover layer 24 is commercially available under the
trademark CURAFORM ISLAND.RTM. offered by Tyco Healthcare Group LP
(d/b/a Covidien).
[0029] Cover layer 24 may act as both a microbial barrier and a
fluid barrier to prevent contaminants from entering the wound bed
"w" and to help maintain the integrity thereof.
[0030] In one embodiment, the cover layer 24 is formed from a
moisture vapor permeable membrane, e.g., to promote the exchange of
oxygen and moisture between the wound bed "w" and the atmosphere.
An example of a membrane that may provide a suitable moisture vapor
transmission rate (MVTR) is a transparent membrane commercially
available under the trade name POLYSKIN.RTM. II offered by Tyco
Healthcare Group LP (d/b/a Covidien). A transparent membrane may
help to permit a visual assessment of wound conditions to be made
without requiring removal of the cover layer 24.
[0031] Wound dressing 12 may include a vacuum port 30 having a
flange 34 to facilitate connection of the vacuum chamber 14 to a
vacuum system. Vacuum port 30 may be configured as a rigid or
flexible, low-profile component and may be adapted to receive a
conduit 36 in a releasable and fluid-tight manner. An adhesive on
at least a portion of the underside of the flange 34 may be used to
provide a mechanism for affixing the vacuum port 30 to the cover
layer 24. The relative positions, size and/or shape of the vacuum
port 30 and the flange 34 may be varied from an embodiment depicted
in FIG. 1. For example, the flange 34 may be positioned within the
vacuum chamber 14 such that an adhesive on at least a portion of an
upper side surface of the flange 34 affixes the vacuum port 30 to
the cover layer 24. A hollow interior portion of the vacuum port 30
provides fluid communication between the conduit 36 and the vacuum
chamber 14. Conduit 36 extends from the vacuum port 30 to provide
fluid communication between the vacuum chamber 14 and the vacuum
source 40. Alternately, the vacuum port 30 may not be included in
the dressing 12 if other provisions are made for providing fluid
communication with the conduit 36.
[0032] Any suitable conduit may be used for the conduit 36,
including conduit fabricated from flexible elastomeric or polymeric
materials. In the negative pressure wound therapy apparatus 10
illustrated in FIG. 1, the conduit 36 includes a first conduit
section 36A, a second conduit section 36B, a third conduit section
36C and a fourth conduit section 36D. The first conduit section 36A
extends from the vacuum port 30 and is coupled via a fluid line
coupling 100 to the second conduit section 36B, which extends to
the collection canister 38. The third conduit section 36C extends
from the collection canister 38 and is coupled via another fluid
line coupling 100 to the fourth conduit section 36D, which extends
to the vacuum source 40. The shape, size and/or number of conduit
sections of the conduit 36 may be varied from the first, second,
third and fourth conduit sections 36A, 36B, 36C and 36D depicted in
FIG. 1.
[0033] The first, second, third and fourth conduit sections 36A,
36B, 36C and 36D of the conduit 36 may be connected to components
of the apparatus 10 by conventional air-tight means, such as, for
example, friction fit, bayonet coupling, or barbed connectors. The
connections may be made permanent. Alternately, a quick-disconnect
or other releasable connection means may be used to provide some
adjustment flexibility to the apparatus 10.
[0034] Collection canister 38 may be formed of any type of
container that is suitable for containing wound fluids. For
example, a semi-rigid plastic bottle may be used for the collection
canister 38. A flexible polymeric pouch or other hollow container
body may be used for the collection canister 38. Collection
canister 38 may contain an absorbent material to consolidate or
contain the wound fluids or debris. For example, super absorbent
polymers (SAP), silica gel, sodium polyacrylate, potassium
polyacrylamide or related compounds may be provided within
collection canister 38. At least a portion of canister 38 may be
transparent or semi-transparent, e.g., to permit a visual
assessment of the wound exudate to assist in evaluating the color,
quality and/or quantity of exudate. A transparent or
semi-transparent portion of the collection canister 38 may permit a
visual assessment to assist in determining the remaining capacity
or open volume of the canister and/or may assist in determining
whether to replace the collection canister 38.
[0035] The collection canister 38 is in fluid communication with
the wound dressing 12 via the first and second conduit sections
36A, 36B. The third and fourth conduit sections 36C, 36D connect
the collection canister 38 to the vacuum source 40 that generates
or otherwise provides a negative pressure to the collection
canister 38. Vacuum source 40 may include a peristaltic pump, a
diaphragmatic pump or other suitable mechanism. Vacuum source 40
may be a miniature pump or micropump that may be biocompatible and
adapted to maintain or draw adequate and therapeutic vacuum levels.
The vacuum level of subatmospheric pressure achieved may be in the
range of about 20 mmHg to about 500 mmHg. In embodiments, the
vacuum level may be about 75 mmHg to about 125 mmHg, or about 40
mmHg to about 80 mmHg. One example of a peristaltic pump that may
be used as the vacuum source 40 is the commercially available
Kangaroo PET Eternal Feeding Pump offered by Tyco Healthcare Group
LP (d/b/a Covidien). Vacuum source 40 may be actuated by an
actuator (not shown) which may be any means known by those skilled
in the art, including, for example, alternating current (AC)
motors, direct current (DC) motors, voice coil actuators,
solenoids, and the like. The actuator may be incorporated within
the vacuum source 40.
[0036] In embodiments, the negative pressure wound therapy
apparatus 10 includes one or more fluid line couplings 100 that
allow for selectable coupling and decoupling of conduit sections.
For example, a fluid line coupling 100 may be used to maintain
fluid communication between the first and second conduit sections
36A, 36B when engaged, and may interrupt fluid flow between the
first and second conduit sections 36A, 36B when disengaged. Thus,
fluid line coupling 100 may facilitate the connection,
disconnection or maintenance of components of the negative pressure
wound therapy apparatus 10, including the replacement of the
collection canister 38. Additional or alternate placement of one or
more fluid line couplings 100 at any location in line with the
conduit 36 may facilitate other procedures. For example, the
placement of a fluid line coupling 100 between the third and fourth
conduit sections 36C, 36D, as depicted in FIG. 1, may facilitate
servicing of the vacuum source 40.
[0037] Referring to FIG. 2, the negative pressure wound therapy
system shown generally as 200 includes a dressing assembly 210, a
wound port assembly 220, an extension assembly 230 and a canister
assembly 240. Dressing assembly 210 is positioned relative to the
wound area to define a vacuum chamber about the wound area to
maintain negative pressure at the wound area. Dressing assembly 210
may be substantially sealed from extraneous air leakage, e.g.,
using adhesive coverings. Wound port assembly 220 is mounted to the
dressing assembly 210. For example, wound port assembly 220 may
include a substantially continuous band of adhesive at its
periphery for affixing the wound port assembly 220 to the dressing
assembly 210. Extension assembly 230 is coupled between the wound
port assembly 220 and the canister assembly 240 and defines a fluid
flow path between the wound port assembly 220 and the canister
assembly 240. A hollow interior of the wound port assembly 220
provides fluid communication between the extension assembly 230 and
the interior of the dressing assembly 210. Dressing assembly 210
and the wound port assembly 220 shown in FIG. 2 are similar to
components of the wound dressing 12 of FIG. 1 and further
description thereof is omitted in the interests of brevity.
[0038] Canister assembly 240 includes a control unit 246 and a
collection canister 242 disposed below the control unit 246.
Control unit 246 and the collection canister 242 may be releasably
coupled. Mechanisms for selective coupling and decoupling of the
control unit 246 and the collection canister 242 include fasteners,
latches, clips, straps, bayonet mounts, magnetic couplings, and
other devices. Collection canister 242 may include any container
suitable for containing wound fluids. In embodiments, the canister
assembly 240 is configured to substantially prevent escape of
exudate into the user's immediate environment when the collection
canister 242 is decoupled from the control unit 246.
[0039] In one embodiment, the negative pressure wound therapy
system 200 is capable of operating in a continuous mode or an
alternating mode. In the continuous mode, the control unit 246
controls a pump (e.g., suction pump 360 shown in FIG. 3) to
continuously supply a selected vacuum level at the collection
canister 242 to create a reduced pressure state within the dressing
assembly 210. In the alternating mode, the control unit 246
controls the pump to alternating supply a first negative pressure,
e.g., about 80 mmHg, at the collection canister 242 for a preset
fixed amount of time and a second negative pressure, e.g., about 50
mmHg, at the collection canister 242 for a different preset fixed
amount of time.
[0040] In general, the output of the pump is directly related to
the degree of air leakage in the negative pressure wound therapy
system 200 and the open volume in the collection canister 242. If
there is sufficient air leakage in the system 200, e.g., at the
dressing assembly 210, the pump can remain on continuously and the
control unit 246 can control negative pressure at the collection
canister 242 by adjusting the pump speed. Alternatively, if there
is not sufficient air leakage in the system 200 to permit the pump
to remain on continuously, the control unit 246 can control
negative pressure at the collection canister 242 by turning the
pump on and off, e.g., for non-equal on/off periods of time.
[0041] Control unit 246 responds to various sensed events by
signaling alarms. Various types of conditions may be signaled by
alarms. In embodiments, control unit 246 is capable of signaling
alarms for failed pressure sensor condition, use odometer expired
condition, watchdog reset condition, failed pump condition, leak
condition, replace canister condition, excessive vacuum condition,
failed LEDs condition, low battery condition, very low battery
condition, and failed battery condition. Priority levels may be
associated with alarms. In embodiments, the priority levels of
alarms are low priority alarm, medium priority alarm, and system
alarm (highest priority). Low priority alarms, when triggered, may
be continuously indicated. Medium priority alarms and system
alarms, when triggered, may have a flashing indication.
[0042] Control unit 246 may stop operation of the pump (e.g.,
suction pump 360 shown in FIG. 3) in response to an alarm, e.g.,
depending on alarm type and/or priority level. In embodiments, the
control unit 246 stops operation of the pump in response to system
alarms, e.g., failed pressure sensor system alarm, use odometer
expired system alarm, watchdog reset system alarm, failed pump
system alarm, excessive vacuum system alarm, and/or failed LEDs
system alarm.
[0043] If an air leak develops in the negative pressure wound
therapy system 200, e.g., at the dressing assembly 210, for which
the control unit 246 cannot compensate by increasing the pump
speed, the control unit 246 may indicate an alarm. For example, the
control unit 246 may indicate a leak alarm after two consecutive
minutes of operation in which the vacuum level is below the current
set point (or below the minimum level of a set point range).
[0044] Audible indicatory means may also be incorporated or
associated with the control unit 246 to notify the user of a
condition, e.g., leak, canister assembly tip, failed pressure
sensor, failed pump, excessive vacuum, or low battery conditions.
The audio indication for some alarm types can be paused by pressing
a pause alarm button (not shown).
[0045] In embodiments, the control unit 246 includes a user
interface (not shown). Control unit 246 also includes a processor
(e.g., 310 shown in FIG. 3). A pressure sensor (e.g., 340 shown in
FIG. 3) is electrically coupled to the processor. The user turns ON
the canister assembly 240 by pressing a power button (not shown).
When the power button is pressed, the control unit 246 performs a
series of internal checks during power up. In one embodiment, after
successfully completing the power-up tasks, the control unit 246
turns on the pump 360 using the stored settings. At initial
activation of the canister assembly 240, the stored settings are
the default settings. In one embodiment, the default settings for
controlling the pump 360 are 80 mmHg and continuous mode. In one
embodiment, the currently stored vacuum level setting can be
altered by the user, e.g., to 50 mmHg. In one embodiment, the
currently stored mode setting can be altered by the user, e.g., to
an alternating mode.
[0046] Canister assembly 240 may be constructed from a variety of
materials such as Lucite.TM. polycarbonate, metals, metal alloys,
plastics, or other durable materials capable of withstanding forces
applied during normal use, and may have some capability of
withstanding possibly excessive forces resulting from misuse.
Collection canister 242 may include a window (not shown) with fluid
level markings or graduations for promoting visual assessment of
the amount of exudate contained within the collection canister 242.
A transparent or partially transparent collection canister 242 may
thus assist in determining the remaining capacity of the collection
canister 242 and/or when the collection canister 242 should be
replaced.
[0047] Referring to FIG. 3, an embodiment of the canister assembly
240 illustrated in FIG. 2 is shown and includes a control unit 246
and a collection canister 242. In embodiments, the canister
assembly 240 is coupled via an extension assembly 230 to a dressing
assembly (e.g., 12 shown in FIG. 1) to apply negative pressure to a
wound to facilitate healing of the wound in accordance with various
treatment modalities.
[0048] Collection canister 242 includes a chamber 335 to collect
wound fluids from the dressing assembly, a canister top 336
disposed over the chamber, a suction port 374 to communicate with
the chamber 335 and the suction pump 360, a canister inlet port 334
to introduce the wound fluids from the dressing assembly into the
chamber 335, and a pressure sensor port 396 to communicate with the
chamber 335 and the pressure sensor 340. Suction port 374 may
include an o-ring on the outside diameter to provide for
appropriate sealing to the suction port when the collection
canister 242 and control unit 246 are attached together. Collection
canister 242 may be disposable. Collection canister 242 may contain
a liner that is disposable.
[0049] In embodiments, the canister inlet port 334 is coupled to
the extension assembly 230. Canister inlet port 334 may be
connectable with the extension assembly 230 by conventional air and
fluid tight means. In embodiments, the canister inlet port 334 may
contain a luer lock or other connector within the purview of those
skilled in the art to secure the end of the extension assembly 230
with the canister inlet port 334. Canister inlet port 334 may be
configured to receive a cap for use to prevent leakage of exudate
and odor from the chamber 335 when the collection canister 242 is
separated from the control unit 246. In alternate embodiments, the
canister inlet port 334 is coupled to a canister inlet conduit
(e.g., 250 shown in FIG. 2) in fluid communication with the
dressing assembly.
[0050] In embodiments, the control unit 246 includes a suction pump
360, a pump inlet conduit 372, a pump outlet conduit 362, a
pressure sensor 340, and a pressure sensor conduit 352.
Additionally, a first filter element 376 and/or a second filter
element 354 may be included. A first connecting channel 378 may be
included to provide fluid communication between the first filter
element 376 and the suction port 374 located on the canister top
336. A second connecting channel 356 may be included to provide
fluid communication between the second filter element 354 and the
pressure sensor port 396 located on the canister top 336.
[0051] Suction pump 360 may provide negative pressure produced by a
piston drawn through a cylinder. Suction pump 360 may be a
peristaltic pump or a diaphragm pump. Suction pump 360 may be a
manual pump or an automated pump. The automated pump may be in the
form of a portable pump, e.g., a small or miniature pump that
maintains or draws adequate and therapeutic vacuum levels. In one
embodiment, the suction pump 360 is a portable, lightweight,
battery-operated, DC motor-driven pump. A vibration damping tape
(not shown), e.g., visco-elastic damping tape, may be applied to
the outer surface of the suction pump 360 to reduce vibration and
its associated noise. Suction pump 360 may be contained within its
own sub-housing (not shown), which may be formed substantially
entirely of molded foam, e.g., used as a silencer to provide sound
mitigation by reducing the sound energy of the expelled air during
operation of the suction pump 360, and may include a carbon loaded
foam. Suction pump 360 provides negative pressure within the
chamber 335 of the collection canister 242 by drawing air through
the suction port 374. Exhaust air from the suction pump 360 is
vented through an exhaust port (not shown) via the pump outlet
conduit 362. Pump outlet conduit 362 may be coupled to one or more
filters (not shown) for filtering the exhaust air from the pump
360.
[0052] In embodiments, the pump inlet conduit 372 provides fluid
communication between the suction pump 360 and the suction port 374
located on the canister top 336, when the control unit 246 and the
collection canister 242 are operablely coupled to each other. In
alternate embodiments, first filter element 376 is disposed between
the suction pump 360 and the suction port 374. Pump inlet conduit
372 may be adapted to provide fluid communication between the
suction pump 360 and the first filter element 376. First filter
element 376 may include one or more filters and is configured to
substantially prevent entry of exudate into the suction pump 360.
In embodiments, the control unit 246 stops operation of the suction
pump 360 when the first filter element 376 becomes occluded. A
variety of filters can be used for the first filter element 376. In
one embodiment, the first filter element 376 includes a hydrophobic
filter that substantially prevents fluids from entering into the
suction pump 360 and potentially causing damage to electronics or
pneumatic components.
[0053] Pressure sensor 340 is in fluid communication with the
collection canister 242 to detect the vacuum level within the
chamber 335 of the collection canister 242. In embodiments, the
pressure sensor 340 generates an electrical signal that varies as a
function of vacuum level within the chamber 335, and the signal is
communicated to the processor 310. Logic associated with the
pressure sensor 340 and the pump 360 may reduce the speed of the
pump 360 or stop operation of the pump 360 in response to the
vacuum level detected by the pressure sensor 340. Any suitable
device capable of detecting pressure may be utilized for the
pressure sensor 340, including, but not limited to, a pressure
switch or a pressure transducer or transmitter:
[0054] In embodiments, the pressure sensor conduit 352 provides
fluid communication between the pressure sensor 340 and the
pressure sensor port 396 located on the canister top 336, when the
control unit 246 and the collection canister 242 are operablely
coupled to each other. In alternate embodiments, second filter
element 354 is disposed between the pressure sensor 340 and the
pressure sensor port 396. Pressure sensor conduit 352 may be
adapted to provide fluid communication between the pressure sensor
340 and the second filter element 354. Second filter element 354
may include one or more filters and is configured to substantially
prevent entry of exudate into the pressure sensor 340. A variety of
filters can be used for the second filter element 354. In one
embodiment, the second filter element 354 includes a hydrophobic
filter that substantially prevents fluid contamination of the
pressure sensor 340.
[0055] In embodiments, the first connecting channel 378 provides
fluid communication between the first filter element 376 and the
suction port 374, when the control unit 246 and the collection
canister 242 are operably coupled to each other. First connecting
channel 378 may be coupled to a control suction port (not shown)
located on the bottom side of the control unit 246 and configured
to engage with the suction port 374 located on the canister top 336
when the control unit 246 and the collection canister 242 are
joined together. In embodiments, the second connecting channel 356
provides fluid communication between the second filter element 354
and the pressure sensor port 396, when the control unit 246 and the
collection canister 242 are operably coupled to each other. Second
connecting channel 356 may be coupled to a control unit pressure
sensor port (not shown) located on the bottom side of the control
unit 246 and configured to engage with the pressure sensor port 396
located on the canister top 336 when the control unit 246 and the
collection canister 242 are joined together.
[0056] Control unit 246 also includes a processor 310. In
embodiments, the processor 310 is electrically coupled via a
transmission line 341 to the pressure sensor 340 and electrically
coupled via a transmission line 361 to the suction pump 360.
Processor 310 may include any type of computing device,
computational circuit, or any type of processor or processing
circuit capable of executing a series of instructions that are
stored in a memory (not shown) of the control unit 246. The series
of instructions may be transmitted via propagated signals for
execution by processor 310 for performing the functions described
herein and to achieve a technical effect in accordance with the
present disclosure. Control unit 246 may also include a user
interface (not shown).
[0057] Canister assembly 240 may also include a sensor 320. In
embodiments, the sensor 320 is used to measure resistance,
capacitance or voltage to provide feedback to the processor 310
indicative of a condition. In embodiments, an electric circuit 328
is electrically coupled via a transmission line 321 between the
sensor 320 and the processor 310. Electric circuit 328 is
configured to detect an electrical property associated with the
sensor 320 and may include various components. Although the
electric circuit 328 is shown as a separate circuit in FIG. 3, it
may be incorporated into the sensor 320, the processor 310, or
other component, e.g., a printed circuit board (not shown)
associated with the processor 310.
[0058] Sensor 320 may include an electrode pair (e.g., 425A, 425B
shown in FIG. 4). Sensor 320 may include multiple electrode pairs.
In embodiments, any change in the resistance, capacitance or
voltage feedback occurring when the electrodes are simultaneously
in contact with exudate in the collection canister 242 is used to
indicate a replace-collection-canister condition or a
full-collection-canister condition (described later in this
disclosure). Examples of sensor and electric circuit embodiments
are disclosed in commonly assigned U.S. patent application Ser. No.
______ filed on ______, 2009, entitled "SENSOR WITH ELECTRICAL
CONTACT PROTECTION FOR USE IN FLUID COLLECTION CANISTER AND
NEGATIVE PRESSURE WOUND THERAPY SYSTEMS INCLUDING SAME", the
disclosure of which is herein incorporated by reference in its
entirety.
[0059] Referring to FIG. 4, an embodiment of the collection
canister 242 of the canister assembly 240 illustrated in FIG. 3 is
shown and includes the canister top 336, the chamber 335, which has
length "L1", the canister inlet port 334, the suction port 374, and
the pressure sensor port 396. The sensor 320 of FIG. 3 is shown as
an electrode pair 425A, 425B in FIG. 4. In embodiments, an electric
potential (or voltage) is applied to the electrodes 425A, 425B.
When a voltage is supplied and the electrodes 425A, 425B are
simultaneously in contact with an ionic fluid, e.g., exudate,
electric current flows via an electro-chemical reaction that occurs
between the ions in the fluid and the electrically polarized
electrodes 425A, 425B.
[0060] In embodiments, one or more electrode pairs (e.g., 425A,
425B shown in FIG. 4) is coupled to an electric circuit (e.g., 328
shown in FIG. 3), which is configured to detect an electrical
properly associated with the electrode pair(s). In embodiments, a
measurement of the change in voltage across the electrode pair(s)
as a result from the flow of current is used to activate an
indicator (not shown) as notification to the user of a condition.
For example, an indicator may be activated to notify the user that
the collection canister 242 is full, which may be referred to as
the full-collection-canister condition. An indicator may be
activated to notify the user that it is time to replace the
collection canister 242, which may be referred to as the
replace-collection-canister condition. The occurrence of a
replace-collection-canister condition indicates that a volume of
exudate (generally being less than the volume of the chamber 355)
has been collected. User notification of a
replace-collection-canister condition may thus provide some
flexibility to the user in the timing of the replacement or
emptying of the collection canister 242, by allowing an additional
time period of operation before the volume of the collected exudate
reaches the maximum volume capacity of the chamber 355.
[0061] Referring to FIG. 5, the bottom side of the canister top 336
illustrated in FIG. 4 is shown and includes the canister inlet port
334, the suction port 374, the pressure sensor port 396 and the two
electrodes 425A, 425B. Additionally, a side wall 580 with a
recessed portion 584 is included. In embodiments, the suction port
374, the pressure sensor port 396 and the two electrodes 425A, 425B
are disposed to the interior of the side wall 580. Side wall 580 is
adapted to provide engagement of the canister top 336 with the
upper end of the peripheral wall of the chamber 335 and may help to
provide sealing of the canister top with the chamber 335. In one
embodiment, the peripheral edge of the recess portion 584 is shaped
to partly encircle the canister inlet port 334. The relative
positions, size and/or shape of the side wall 580, the canister
inlet port 334, the suction port 374, the pressure sensor port 396
and the two electrodes 425A, 425B may be varied from an embodiment
depicted in FIG. 5.
[0062] Canister top 336 may be fabricated from plastic materials by
molding techniques. Canister top 336 may be secured to the open top
of the collection canister 242 by friction fit between the side
wall 580 and the peripheral wall of the chamber 335. Side wall 580
may be fixably attached to the upper end of the peripheral wall of
the chamber 335, e.g., using an ultrasonic welding process.
[0063] In FIGS. 6 through 8, another embodiment of a canister top
of a collection canister (e.g., 242 shown in FIG. 3) is shown.
Canister top 636 includes a canister inlet port 634, a suction port
674 and a pressure sensor port 696. In embodiments, the canister
top 636 may also include one or more electrode pairs, e.g.,
electrode pair 425A, 425B, as described above. Canister top 636
includes a side wall 680, an outer sealing rib "R1" and an
isolating rib "R2". In embodiments, the canister top 636 may
include support elements 612 that are configured to provide support
for a filter membrane (e.g., 760 shown in FIG. 7).
[0064] As shown in FIGS. 6 and 8, the outer sealing rib "R1" and
the isolating rib "R2" define two chambers, "A1" and "A2", which
are pneumatically isolated from each other by the isolating rib
"R2". In embodiments, the first chamber "A1" includes the pressure
sensor port 696 and the second chamber "A2" includes the suction
port 674. In alternate embodiments, the first chamber "A1" includes
the suction port 674 and the second chamber "A2" includes the
pressure sensor port 696. Although the sensor port 696 and the
suction port 674 are shown and described as included in
pneumatically isolated chambers, it is contemplated herein that the
pressure sensor port 696 and the suction port 674 may be included
in same chamber.
[0065] In embodiments, the exterior wall of the outer sealing rib
"R1", or portion thereof, is disposed directly adjacent to or
substantially adjacent to the side wall 680. In embodiments, the
isolating rib "R2", or portion thereof, is spaced apart from the
interior wall of the outer sealing rib "R1". In the illustrated
embodiment, the first chamber "A1" is an elongated pathway that
extends approximately around the perimeter of the canister top and
is formed between the isolating rib "R2" and the outer sealing rib
"R1". Although the first chamber "A1" is shown and described as an
elongated pathway including the pressure sensor port 696, it is
contemplated herein that the first chamber "A1" may include
multiple pathways in fluid communication with the pressure sensor
port 696.
[0066] Referring to FIG. 7, the canister top 636 of FIG. 6 is shown
and includes a filter membrane 760 disposed to the interior of the
side wall 680. Filter membrane 760 may include a micro-pore filter
membrane. In embodiments, the filter membrane 760 is cut to the
profile of the outer sealing rib "R1". Filter membrane 760 is
attached to the isolating rib "R2" and the outer sealing rib "R1"
and may be attached to the support elements 612. Filter membrane
760 may be attached to the outer sealing rib "R1" and the isolating
rib "R2" by adhesive such as UV cure, catalyzed, vulcanized or
other type, or welded by ultrasonic or radio frequency means.
[0067] Filter membrane 760 generally allows air flow while
substantially preventing liquid and bacterial passage therethrough.
In embodiments, the filter membrane 760 allows air flow to the
suction pump (e.g., 360 shown in FIG. 3) and allows the vacuum
level at the collection canister to be monitored using a pressure
sensor (e.g., 340 shown in FIG. 3) in fluid communication with the
collection canister through the filter membrane 760. Negative
pressure wound therapy systems including a collection canister
having a canister top in accordance with embodiments of the present
disclosure may be capable of accurate measurement of vacuum levels
within the collection canister and capable of providing negative
pressure therapy for varied orientations of the collection
canister.
[0068] Referring to FIG. 9, another embodiment of a collection
canister 942 is shown and includes a chamber 935 to collect fluids
and a canister top 936 disposed over the chamber 935. The canister
top 936 includes a bottom side facing into the chamber 935. The
bottom side of the canister top 936 includes first and second ribs,
"R1" and "R2", disposed thereon, and a side wall 680, as described
above. A filter membrane 960 is attached to the first and second
ribs, "R1" and "R2". Canister top 936 also includes a first port
974 to communicate with the chamber 935 and a pressure source
external to the chamber, and a second port to communicate with the
chamber 935 and a sensor external to the chamber 935. The first
port is in fluid communication with a first area "A1", which is
bounded by the filter membrane 960, the first and second ribs, "R1"
and "R2", and the bottom side of the canister top 936. The second
port is in fluid communication with a second area"A2", which is
bounded by the filter membrane 960, the second rib "R2" and the
bottom side of the canister top 936. In embodiments, the canister
top 936 also includes a third port 934 to introduce the fluids into
the chamber 935.
[0069] Referring to FIGS. 10 through 12, the canister top 936 of
the collection canister 942 of FIG. 9 is shown. Canister top 936
includes the side wall 680 shown in FIGS. 6 through 8. Canister top
936 includes a first port 974 and a second port 996 and may include
a third port 934, as described above. In embodiments, the canister
top 936 may include one or more electrode pairs, e.g., electrode
pair 925A, 925B. Electrode pair 925A, 925B shown in FIG. 9 is
substantially similar to the electrode pair 425A, 425B of the
collection canister 242 illustrated in FIG. 4 and further
description thereof is omitted in the interests of brevity.
[0070] Canister top 936 also includes a first rib "R1" and a second
rib "R2". As shown in FIGS. 10 and 12, the first rib "R1" and the
second rib "R2" define two areas, "A1" and "A2", which are
pneumatically isolated from each other by the second rib "R2". As
shown in FIG. 11, the filter membrane 960 is cut to the profile of
the first rib "R1". Filter membrane 960 may include any suitable
material capable of allowing air flow while substantially
preventing liquid and bacterial passage therethrough. Filter
membrane 960 may include a micro-pore filter membrane. In
embodiments, the canister top 936 may include support elements 912
that are configured to provide support for the filter membrane 960.
In embodiments, the filter membrane 960 is attached to the first
rib "R1" and the second rib "R2" and may be attached to the support
elements 912. The relative positions, size and/or shape of the
first rib "R1", the second rib "R2" and the support elements 912
may be varied from an embodiment depicted in FIGS. 10 through
[0071] Although embodiments of the present disclosure have been
described in detail with reference to the accompanying drawings for
the purpose of illustration and description, it is to be understood
that the inventive processes and apparatus are not to be construed
as limited thereby. It will be apparent to those of ordinary skill
in the art that various modifications to the foregoing embodiments
may be made without departing from the scope of the disclosure.
* * * * *