U.S. patent application number 15/223158 was filed with the patent office on 2017-02-02 for wound therapy device pressure monitoring and control system.
This patent application is currently assigned to INNOVATIVE THERAPIES, INC.. The applicant listed for this patent is INNOVATIVE THERAPIES, INC.. Invention is credited to BRENT LEE BURCHFIELD, RAYMOND READE HARPHAM, ALAN JOHN MARTIN, DAVID MALCOLM TUMEY, TIANNING XU.
Application Number | 20170028111 15/223158 |
Document ID | / |
Family ID | 56610016 |
Filed Date | 2017-02-02 |
United States Patent
Application |
20170028111 |
Kind Code |
A1 |
TUMEY; DAVID MALCOLM ; et
al. |
February 2, 2017 |
WOUND THERAPY DEVICE PRESSURE MONITORING AND CONTROL SYSTEM
Abstract
A new system for negative pressure wound therapy is described.
The system includes a patient tube set connecting the wound
dressing to the suction container. The patient tube set provides
separate channels for applying suction to the wound site and
sensing the therapeutic pressure at the wound site. A restrictor
valve may also be included in order to introduce a small air leak
into the system to prevent occlusions in the patient tube set.
Inventors: |
TUMEY; DAVID MALCOLM; (CORAL
SPRINGS, FL) ; XU; TIANNING; (DULUTH, GA) ;
MARTIN; ALAN JOHN; (POMPANO BEACH, FL) ; BURCHFIELD;
BRENT LEE; (POWELL, OH) ; HARPHAM; RAYMOND READE;
(COLUMBUS, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
INNOVATIVE THERAPIES, INC. |
POMPANO BEACH |
FL |
US |
|
|
Assignee: |
INNOVATIVE THERAPIES, INC.
POMPANO BEACH
FL
|
Family ID: |
56610016 |
Appl. No.: |
15/223158 |
Filed: |
July 29, 2016 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
62198514 |
Jul 29, 2015 |
|
|
|
62296679 |
Feb 18, 2016 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M 2039/082 20130101;
F16K 1/02 20130101; F16K 31/504 20130101; A61M 1/0068 20140204;
A61M 2205/3344 20130101; A61M 1/0025 20140204; A61M 1/0084
20130101; A61M 39/08 20130101; A61M 2205/3331 20130101; A61M 1/0086
20140204; A61M 1/0088 20130101; A61M 1/0072 20140204; A61M 1/0031
20130101; A61M 1/0092 20140204 |
International
Class: |
A61M 1/00 20060101
A61M001/00; A61M 39/08 20060101 A61M039/08 |
Claims
1. A wound therapy system comprising: a wound dressing; a pressure
sensor; a container having an internal chamber; a vacuum source
pneumatically associated with the internal chamber of the
container; and a tube set comprising a first tube and a second tube
positioned inside a lumen of the first tube, wherein a space
between the first tube and the second tube forms a fluid channel,
and wherein a lumen of the second tube forms a sensor channel in
the tube set; wherein the wound dressing is pneumatically
associated with the internal chamber of the container by the fluid
channel of the tube set; wherein the wound dressing is
pneumatically associated with the pressure sensor by the sensor
channel of the tube set; and wherein a crushing force required to
occlude the fluid channel is greater than a crushing force required
to occlude a fluid channel of a comparison tube set that does not
include a second tube positioned inside a lumen of the first
tube.
2. The wound therapy system of claim 1, wherein the fluid channel
and the sensor channel of the tube set are formed by a first tube
and a second tube.
3. The wound therapy system of claim 2, wherein the second tube is
formed within the first tube, wherein the sensor channel is a lumen
of the second tube, and wherein the fluid channel is a space
between the first tube and second tube.
4. The wound therapy system of claim 2, wherein the container has a
first port comprising a first attachment and a second attachment;
wherein a first end of the first tube is coupled to the wound
dressing and a second end of the first tube is coupled to the first
attachment of the first port; and wherein a first end of the second
tube connects to the wound dressing and a second end of the second
tube connects to the second attachment of the first port.
5. The wound therapy system of claim 4, wherein the container
further comprises a second port and a sensor tube, wherein a first
end of the sensor tube is connected to the second attachment of the
first port and the second end of the sensor tube is connected to
the second port, and wherein the pressure sensor is pneumatically
associated with the second port on the container.
6. The wound therapy system of claim 4, further comprising an
adapter that couples the second end of the first tube to the first
attachment of the first port and the second end of the second tube
to the second attachment of the first port.
7. The wound therapy system of claim 4, wherein the wound dressing
is a first wound dressing, and wherein the wound therapy system
further comprises a second wound dressing and a y-connector,
wherein a first port of the y-connector is pneumatically associated
with the first port of the container, wherein a second port of the
y-connector is pneumatically associated with the first wound
dressing, and wherein a third port of the y-connector is
pneumatically associated with the second wound dressing.
8. The wound therapy system of claim 1, wherein the fluid channel
and the sensor channel are pneumatically associated with one
another at the wound dressing.
9. The wound therapy system of claim 1, further comprising a
pressure sensor pneumatically associated with the vacuum
source.
10. The wound therapy system of claim 1, further comprising a
restrictor pneumatically associated with the wound dressing by the
sensor channel of the patient tube, wherein the restrictor has a
hole that is configured to allow air to leak into the wound therapy
system.
11. The wound therapy system of claim 10, wherein the restrictor
comprises: a body having a first port and a second port; a cap
coupled to the first port of the body, the cap having a hole; and a
porous material positioned between the cap and the first port of
the body; wherein air is configured to enter the device through the
hole in the cap and pass through the porous material before
entering the first port of the body.
12. The wound therapy system of claim 11, wherein the restrictor is
adjustable, and wherein tightening a connection between the cap and
the body compresses the porous material and decreases a rate of
airflow across the porous material.
13. The wound therapy system of claim 10, wherein the restrictor
leaks air into the system at a rate of about 0.05-0.1 liters per
minute when the vacuum source applies a vacuum to the system.
14. The wound therapy system of claim 10, wherein vacuum source is
configured to compensate for air leaking into the system such that
the pressure at the wound dressing is not substantially
altered.
15. The wound therapy system of claim 1, wherein the sensor channel
has a cross-sectional area of at least 0.75 mm.sup.2.
16. The wound therapy system of claim 1, wherein the tube set
comprises exactly one sensor channel.
17. The wound therapy system of claim 1, wherein the tube set
comprises a plurality of sensor channels.
18. The wound therapy system of claim 1, wherein the tube set is a
first tube set, and wherein the wound therapy system further
comprises a second tube set having a fluid channel and a sensor
channel, and a valve positioned in-line between the first tube set
and the second tube set.
19. The wound therapy system of claim 18, wherein the valve has an
open position and a closed position; wherein the valve, when in the
open position, allows communication between the fluid channel of
the first tube set and the fluid channel of the second tube set,
and also allows communication between the sensor channel of the
first tube set and the sensor channel of the second tube set; and
wherein the valve, when in the closed position, blocks
communication between the fluid channel of the first tube set and
the fluid channel of the second tube set, and also blocks
communication between the sensor channel of the first tube set and
the sensor channel of the second tube set.
20. The wound therapy system of claim 1, wherein the first tube and
the second tube are able to maintain their shape when a vacuum is
applied by the vacuum source.
21. The wound therapy system of claim 1, wherein the fluid channel
is substantially unobstructed.
22. A method of wound therapy comprising: applying a dressing to a
wound, wherein the dressing is coupled to a tube set comprising a
fluid channel and a sensor channel; applying a vacuum to the fluid
channel, wherein the vacuum draws exudate from the wound into the
fluid channel; and providing a restrictor pneumatically associated
with the wound dressing by the sensor channel, the restrictor
having a hole through which air can leak into the sensor channel,
wherein the air pushes fluids from the wound dressing into the
fluid channel of the tube set.
23. The method of claim 22, wherein the step of applying the vacuum
to the fluid channel allows air to continuously leak from the
restrictor into the sensor channel.
24. The method of claim 22, further comprising a step of opening
the restrictor intermittently to allow air to leak into the sensor
channel when the restrictor is open.
25. The method of claim 24, wherein the restrictor is a
solenoid.
26. The method of claim 22, further comprising: measuring a
therapeutic pressure at the dressing using a pressure sensor
connected to the sensor channel; and adjusting the pressure of the
vacuum applied to the fluid channel based on the therapeutic
pressure measured by the pressure sensor.
27. The method of claim 22, further comprising a step of forming
the tube set such that the tube set comprises an inner tube and an
outer tube, wherein the sensor channel is a lumen of the inner
tube, and wherein the fluid channel is a space between the outer
tube and inner tube.
28. The method of claim 22, further comprising a step of adjusting
the restrictor to change the rate at which air leaks into the
system.
29. A device for creating an air leak, the device comprising: a
body having a first port in communication with a second port; a cap
coupled to the first port of the body, the cap having a hole; and a
porous material positioned between the cap and the first port of
the body; wherein air is configured to enter the device through the
hole in the cap and pass through the porous material before
entering the body via the first port.
30. The device of claim 29, wherein tightening a connection between
the cap and the body compresses the porous material and decreases a
rate of airflow across the porous material.
31. The device of claim 29, wherein the device is configured to
allow air to flow out of the second port at a rate of 0.05-0.1
liters per minute.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent
Application No. 62/198,514, filed on Jul. 29, 2015, titled, "WOUND
THERAPY DEVICE PRESSURE MONITORING AND CONTROL SYSTEM" and U.S.
Provisional Patent Application No. 62/296,679, filed on Feb. 18,
2016, titled "WOUND THERAPY DEVICE PRESSURE MONITORING AND CONTROL
SYSTEM". The entirety of each of these applications is hereby
incorporated by reference.
BACKGROUND
[0002] Negative pressure wound therapy includes a vacuum source
connected to a wound dressing. Various porous dressings comprising
gauze, felts, foams, beads and/or fibers can be used in conjunction
with a semi-permeable cover and a controlled vacuum source. A
collection container may be used to collect wound exudate and fluid
that drains from the wound.
[0003] In addition to using negative pressure wound therapy, many
devices employ concomitant wound irrigation. For example, a known
wound healing apparatus includes a porous dressing made of
polyurethane foam placed adjacent a wound and covered by a
semi-permeable and flexible plastic sheet. The dressing further
includes fluid supply and fluid drainage connections in
communication with the cavity formed by the cover and foam. The
fluid supply is connected to a fluid source that can include an
aqueous-based topical antibiotic solution or isotonic saline, for
example, for use in providing therapy to the wound. The fluid
drainage can be connected to a vacuum source where fluid can be
removed from the cavity and subatmospheric pressures can be
maintained inside the cavity.
[0004] Other devices use vacuum sealing of wound dressings
including polyvinyl alcohol foam cut to size and stapled to the
margins of the wound. The dressings are covered by a semi-permeable
membrane while suction and fluid connections are provided by small
plastic tubes introduced subcutaneously into the cavity formed by
the foam and cover. Such devices alternate in time between vacuum
drainage and the introduction of aqueous medicaments to the wound
site.
[0005] However, such devices may fail to address the problems
caused by standing fluid and occlusions in a tube connecting the
wound dressing to the collection container.
SUMMARY
[0006] A wound therapy system is described, which comprises a wound
dressing, a pressure sensor, a container having an internal
chamber, a vacuum source pneumatically associated with the internal
chamber of the container, and a tube set comprising a first tube
and a second tube positioned inside a lumen of the first tube. A
space between the first tube and the second tube forms a fluid
channel, and a lumen of the second tube forms a sensor channel in
the tube set. The wound dressing may be pneumatically associated
with the internal chamber of the container by the fluid channel of
the tube set. The wound dressing may be pneumatically associated
with the pressure sensor by the sensor channel of the tube set. A
crushing force required to occlude the fluid channel is greater
than a crushing force required to occlude a fluid channel of a
comparison tube set that does not include a second tube positioned
inside a lumen of the first tube.
[0007] A method of wound therapy is also described, which comprises
applying a dressing to a wound, wherein the dressing is coupled to
a tube set comprising a fluid channel and a sensor channel;
applying a vacuum to the fluid channel, wherein the vacuum draws
exudate from the wound into the fluid channel; and providing a
restrictor pneumatically associated with the wound dressing by the
sensor channel, the restrictor having a hole through which air can
leak into the sensor channel, wherein the air pushes exudate from
the wound into the fluid channel of the tube set.
[0008] A device for creating an air leak is also described, the
device comprising a body having a first port in communication with
a second port; a cap coupled to the first port of the body, the cap
having a hole; and a porous material positioned between the cap and
the first port of the body. Air may be configured to enter the
device through the hole in the cap and pass through the porous
material before entering the body via the first port.
BRIEF DESCRIPTION OF THE FIGURES
[0009] FIGS. 1A-1C show schematic depictions of various
configurations of a negative pressure wound therapy system.
[0010] FIG. 2A shows a perspective view of a first embodiment of a
collection container used in the negative pressure wound therapy
system shown in FIGS. 1A-1C.
[0011] FIG. 2B shows a top view of the collection container shown
in FIG. 2A.
[0012] FIG. 2C shows a cross-sectional view of the collection
container shown in FIGS. 2A-2B, taken along line 2C.
[0013] FIG. 3A shows a perspective view of a second embodiment of a
collection container used in the negative pressure wound therapy
system shown in FIGS. 1A-1C.
[0014] FIG. 3B shows a perspective view of a lid of the second
embodiment of the collection container shown in FIG. 3A.
[0015] FIG. 3C shows a top view of the lid shown in FIG. 3B.
[0016] FIG. 3D shows a cross-sectional view of the lid shown in
FIGS. 3B-3C, taken along line 3d.
[0017] FIG. 3E shows a cross-sectional view of the lid shown in
FIGS. 3B-3C, taken along line 3e. For simplicity, the sensor tube
connected to the patient port (shown in FIG. 3D) is not shown in
FIG. 3E.
[0018] FIG. 4 shows a perspective view of a first embodiment of a
patient tube set used in the negative pressure wound therapy system
shown in FIGS. 1A-1C.
[0019] FIG. 5 shows a perspective view of a second embodiment of a
patient tube set used in the negative pressure wound therapy system
shown in FIGS. 1A-1C.
[0020] FIG. 6 shows a perspective view of a collection container,
wound dressing, and associated tubing used in the negative pressure
wound therapy system shown in FIGS. 1A-1C.
[0021] FIG. 7 shows a cross-sectional view of the collection
container, wound dressing, and associated tubing shown in FIG. 6,
taken along line 7.
[0022] FIG. 8 shows a perspective view of a first embodiment of an
adjustable restrictor used in the negative pressure wound therapy
system shown in FIGS. 1A-1C.
[0023] FIG. 9 shows a cross-sectional view of the adjustable
restrictor shown in FIG. 8, taken along line 9.
[0024] FIG. 10 shows a perspective view of a second embodiment of
an adjustable restrictor used in the negative pressure wound
therapy system shown in FIGS. 1A-1C.
[0025] FIG. 11 shows a cross-sectional view of the adjustable
restrictor shown in FIG. 10, taken along line 11.
[0026] FIG. 12 shows a perspective view of an adapter used in the
negative pressure wound therapy system shown in FIGS. 1B-1C.
[0027] FIG. 13 shows a top view of the adapter shown in FIG.
12.
[0028] FIG. 14 shows a cross-sectional view of the adapter shown in
FIGS. 12-13, taken along line 14.
[0029] FIG. 15A shows a perspective view of a gasket used in the
negative pressure wound therapy system shown in FIGS. 1B-1C.
[0030] FIG. 15B shows a cross-sectional view of the gasket shown in
FIG. 15A, taken along line 15b.
[0031] FIG. 16A shows a perspective view of the adapter shown in
FIG. 12 connected to the lid shown in FIG. 3B.
[0032] FIG. 16B shows a cross-sectional view of the lid and adapter
shown in FIG. 16A, taken along line 16b, and further includes the
gasket shown in FIG. 15A (which is not visible in FIG. 16A).
[0033] FIG. 16C shows a detailed cross-sectional view of the lid,
adapter, and gasket shown in FIG. 16B.
[0034] FIG. 17 shows a perspective view of a y-connector used in
the negative pressure wound therapy system shown in FIG. 1C.
[0035] FIG. 18 shows a top view of the y-connector shown in FIG.
17.
[0036] FIG. 19 shows a cross-sectional view of the y-connector
shown in FIGS. 17-18, taken along line 19.
[0037] FIG. 20 shows a cross-sectional view of the y-connector
shown in FIG. 17, taken along line 20.
[0038] FIG. 21 shows a perspective view of a valve (in an open
position) used in the configurations of the negative pressure wound
therapy system shown in FIGS. 1B-1C.
[0039] FIG. 22 shows a side view of the valve (in an open position)
shown in FIG. 21.
[0040] FIG. 23 shows a cross-sectional view of the valve (in an
open position) shown in FIG. 21, taken along line 23.
[0041] FIG. 24 shows a cross-sectional view of the valve (in an
open position) shown in FIG. 21, taken along line 24.
[0042] FIG. 25 shows a perspective view of the valve of FIGS.
21-24, now shown in a closed position.
[0043] FIG. 26 shows a side view of the valve (in a closed
position) shown in FIG. 25.
[0044] FIG. 27 shows a cross-sectional view of the valve (in a
closed position) shown in FIG. 25, taken along line 27.
[0045] FIG. 28 shows a cross-sectional view of the valve (in a
closed position) shown in FIG. 25, taken along line 28.
[0046] FIG. 29 shows a perspective view of a housing used in the
valve of FIGS. 21-28.
[0047] FIG. 30 shows a cross-sectional view of the housing shown in
FIG. 29, taken along line 30.
[0048] FIG. 31 shows a cross-sectional view of the housing shown in
FIG. 29, taken along line 31.
[0049] FIG. 32 shows a perspective view of a slide switch used in
the valve of FIGS. 21-28.
[0050] FIG. 33 shows a side view of the slide switch shown in FIG.
32.
[0051] FIG. 34 shows a perspective view of a valve seat used in the
valve of FIGS. 21-28.
[0052] FIG. 35 shows a cross-sectional view of the valve seat shown
in FIG. 34, taken along line 35.
[0053] FIG. 36 shows a cross-sectional view of the valve seat shown
in FIG. 34, taken along line 36.
[0054] FIG. 37 shows a cross-sectional view of the valve seat shown
in FIG. 34, taken along line 37.
[0055] FIG. 38 shows a perspective view of a wound dressing
subassembly used in the negative pressure wound therapy system
shown in FIGS. 1B-1C.
[0056] FIG. 39 shows a perspective view of a y-connector
subassembly used in the negative pressure wound therapy system
shown in FIG. 1C.
[0057] FIG. 40 shows a side view of a Comparison A tube set.
[0058] FIG. 41 shows a side view of a Comparison B tube set.
[0059] FIG. 42 shows a side view of an Example 1 tube set.
[0060] FIG. 43 shows a side view of test set-up including a
mechanical test system and a sample tube set.
[0061] FIG. 44 shows a front view of the test set-up of FIG.
43.
[0062] FIGS. 45-46 shows two test configurations used to test the
sample tube sets in the EXAMPLE section.
DETAILED DESCRIPTION
[0063] The detailed description set forth below, in connection with
the appended drawings, is intended as a description of various
configurations and is not intended to represent the only
configurations in which the concepts described herein may be
practiced. The detailed description includes specific details for
the purpose of providing a thorough understanding of the various
concepts. However, it will be apparent to those skilled in the art
that these concepts may be practiced without these specific
details.
[0064] Various aspects of a negative pressure wound therapy system
may be illustrated by describing components that are coupled,
attached, connected, pneumatically associated, and/or joined
together. As used herein, the terms "coupled", "attached",
"connected", "pneumatically associated", "in communication with",
and/or "joined" are interchangeably used to indicate either a
direct connection between two components or, where appropriate, an
indirect connection to one another through intervening or
intermediate components. In contrast, when a component is referred
to as being "directly coupled", "directly attached", "directly
connected" and/or "directly joined" to another component there are
no intervening elements shown in said examples.
[0065] As illustrated in FIGS. 1A-1C, a negative pressure wound
therapy system 100 may include a microcontroller 101, a membrane
keypad and display 160, one or more vacuum pumps 105 and/or 107, a
collection container 165, one or more fluid barriers 129 and/or
113, a wound dressing 123, a battery 127, a muffler 128, a patient
tube set 181, an adjustable restrictor 200, a solenoid 177, an
optional orifice restrictor 178, a pump pressure sensor 109, and a
wound pressure sensor 173. These components may be connected
through a series of adapters, connectors, pneumatic tubes and
electrical cables. Various configurations of the system 100 are
contemplated, and example configurations of the system 100 are
shown in FIGS. 1B and 1C. The system 100 may also include a one or
more valves 500, additional wound dressings 123, y-connector 400,
and various adapters 300.
[0066] Many of the components may be provided as part of a pump
unit 120, which may include one or more of the microcontroller 101,
membrane keypad and display 160, vacuum pumps 105 and/or 107, fluid
barrier 113, battery 127, muffler 128, adjustable restrictor 200,
solenoid 177, orifice restrictor 178, pump pressure sensor 109,
wound pressure sensor 173, and related pneumatic tubes and
electrical cables. Pneumatic tubes 176 and 115 may be separate
components used to connect the collection container 165 to the pump
unit 120, or they may preferably be provided inside the pump unit
120. The pump unit 120 may have a vacuum port which connects to
pneumatic tube 115, and a sensor port which connects to pneumatic
tube 176. If pneumatic tubes 176 and 115 are provided inside the
pump unit 120, the pump unit 120 may have a vacuum port at the end
of pneumatic tube 115 that interfaces with the canister 165, and a
sensor port at the end of pneumatic tube 176 that interfaces with
the canister 165.
Controller
[0067] As illustrated in FIGS. 1A-1C, the negative pressure wound
therapy system 100 generally includes a microcontroller 101 having
an embedded microprocessor 102, Random Access Memory (RAM) 103 and
Read Only Memory (ROM) 104. ROM 104 contains programming
instructions for a control algorithm 150. ROM 104 may be
non-volatile and may retain its programming when the power is
terminated. RAM 103 is utilized by the control algorithm 150 for
storing variables such as pressure measurements, alarm counts and
the like, which the control algorithm 150 uses while generating and
maintaining the vacuum.
Vacuum Sources
[0068] Microcontroller 101 is electrically associated with, and
controls the operation of, a first vacuum pump 105 and an optional
second vacuum pump 107 through electrical cables 106 and 108
respectively. To increase the airflow of the system, additional
vacuum pumps may also be included. Electrical cables used with
system 100 may be multi-conductor ribbon cables or flat flexible
cables (FFC), or any cable that allows communication between two or
more system components. First vacuum pump 105 and optional second
vacuum pump 107 may be one of many types including, for example,
the pumps sold under the trademarks Hargraves.RTM. and Thomas.RTM..
Vacuum pumps 105 and 107 may use, for example, a reciprocating
diaphragm or piston to create vacuum and are typically powered by a
D.C. motor that may also optionally use a brushless commutator for
increased reliability and longevity. Vacuum pumps 105 and 107 may
also be, for example, a rotary diaphragm pump which is a hybrid of
a rotary pump and a diaphragm pump. Although some embodiments
include one or more pumps as the vacuum source, the system 100 may
use any type of vacuum source, including a squeeze bulb, a
spring-loaded suction device, or hospital-supplied "wall suction"
with pressure regulator/controller.
[0069] Vacuum pumps 105 and/or 107 may be capable of producing
vacuum pressures, which are pressures that have lower absolute
values compared to the atmospheric pressure of the surrounding
environment. The vacuum pumps 105 and/or 107 may be able to produce
vacuum pressures that range from about 70 mmHg below atmospheric
pressure to about 150 mmHg below atmospheric pressure, where vacuum
pressures of 150 mmHg below atmospheric pressure are stronger
vacuums compared to vacuum pressures of 70 mmHg below atmospheric
pressure. For example, at standard atmospheric pressure of 760
mmHg, vacuum pumps 105 and/or 107 may generate a vacuum pressure
having an absolute value ranging from about 610 mmHg to about 690
mmHg, where vacuum pressures of 610 mmHg are stronger vacuums
compared to vacuum pressures of 690 mmHg. In addition, vacuum pumps
105 and/or 107 may also be capable of producing vacuum pressures
outside this range. For example, vacuum pumps 105 and/or 107 may be
able to produce vacuum pressures that range from about 50 mmHg
below atmospheric pressure to about 200 mmHg below atmospheric
pressure.
[0070] An acoustic muffler 128 may be pneumatically associated with
the exhaust ports of vacuum pumps 105 and/or 107 through pneumatic
exhaust tubing 138 and is configured to reduce exhaust noise
produced by the pumps during operation. An activated carbon odor
trap may also be associated with the exhaust ports of vacuum pumps
105 and/or 107 through pneumatic exhaust tubing 138.
[0071] In normal operation of the negative pressure wound therapy
system 100, first vacuum pump 105 (and optionally one or more
additional vacuum pumps, such as a second vacuum pump 107) may be
used to generate an initial or "draw-down" vacuum while the
optional second vacuum pump 107 may be used to maintain a desired
vacuum within the system 100, compensating for leaks or pressure
fluctuations. The second vacuum pump 107 may be smaller and quieter
than the first vacuum pump 105 providing a means to maintain the
desired pressure without significantly disturbing the patient.
Display
[0072] A membrane keypad and display 160 may be electrically
associated with microcontroller 101 through electrical cable 164.
Membrane switches 161 provide power control, while membrane
switches 162 may be used to preset the desired vacuum levels. Light
emitting diodes (LEDs) 163 may be provided to indicate alarm
conditions associated with collection container 165 fluid level and
wound dressing 123 leaks. Preferably, an LCD display could be used
in place of the LEDs 163 to indicate alarm conditions.
Power
[0073] The system 100 may be powered by an external source of
power. A battery 127 is optionally provided to permit portable
operation of the negative pressure wound therapy system 100.
Battery 127, which may be Lithium Ion, Nickel-Metal-Hydride (NiMH),
Nickel-Cadmium, (NiCd) or their equivalent, is electrically
associated with microcontroller 101 through electrical cables 136
and 137. Battery 127 is charged by circuits related with
microcontroller 101 while an external source of power is available
such as would typically be supplied by a low-voltage A.C. adapter.
When an external source of power is not available and the unit is
to operate in a portable mode, battery 127 supplies power to the
negative pressure wound therapy system 100.
Collection Container
[0074] The negative pressure wound therapy system 100 includes a
collection container 165. A first embodiment of the collection
container 165 is shown in FIGS. 2A-2C, and a second embodiment of a
collection container 165 is shown in FIG. 3A. The collection
container 165 encloses an internal chamber 166 into which fluid and
exudate may drain. The collection container 165 may be a canister,
an in-line vessel, or any container capable of collecting exudate.
The volume of the collection container 165 may vary. The collection
container 165 may be formed as a cylinder (as shown in FIG. 3A), an
inverted truncated cone (as shown in FIG. 2A), or any number of
other shapes. In a preferred embodiment, the collection container
165 may be substantially cylindrical. In some embodiments, the
volume of the collection container 165 may be between about 300 mL
and about 1200 mL. It may be preferable that collection container
165 has a volume which does not exceed about 1500 mL in order to
prevent accidental exsanguination of a patient in the event
hemostasis has not yet been achieved at the wound site.
[0075] The embodiments shown in FIGS. 2A-2C and 3A-3E have three
openings in the collection container 165: a patient port 167, a
vacuum port 168, and a sensor port 169. However, fewer or
additional openings are possible. In FIGS. 2A-2C, 6, and 7, the
patient port 167, vacuum port 168, and sensor port 169 are linearly
arranged on the collection container 165. However, other port
arrangements are also possible. For example, the patient port 167,
vacuum port 168, and sensor port 169 may form a triangle on the
collection container 165, as shown in FIGS. 3A-3E. Beneficially,
the vacuum port 168 and sensor port 169 may be positioned on the
collection container 165 such that they may be able to connect
directly to ports on the pump unit 120 without the use of
additional pneumatic tubing. The vacuum port 168 and/or sensor port
169 may include a locking feature 168a that allows the collection
container to connect to the pump unit 120 (for example, a groove
which may receive a latch on one of the ports on the pump unit
120). However, pneumatic tubing 176, 115 outside the pump unit 120
(as shown in FIGS. 1A-1C) may also be used to connect the vacuum
port 168 and sensor port 169 on the collection container 165 to
ports on the pump unit 120.
[0076] The internal chamber 166 of the collection container 165 may
be pneumatically associated with vacuum pumps 105 and/or 107
through a tube 115 connected to the vacuum port 168 of the
collection container 165. Tube 115 may connect to first vacuum pump
105 and optional second vacuum pump 107 through "T" connectors 111
and 112, respectively.
[0077] A fluid barrier 129 may be provided with the collection
container 165. The fluid barrier 129 may be proximate to the vacuum
port 168 and may be configured to prevent fluids collected in the
collection container 165 from escaping through the vacuum port 168
into tube 115, which could potentially damage vacuum pumps 105 and
107. The fluid barrier 129 may be a porous polymer hydrophobic
filter such as those available under the trademark Porex.RTM..
Alternatively, the fluid barrier 129 may have a mechanical float
design or may have one or more membranes of hydrophobic material
such as those available under the trademark GoreTex.TM.. A
secondary barrier 113 may include a hydrophobic membrane which may
be provided in line with tube 115 to prevent fluid ingress into the
system 100 in the event fluid barrier 129 fails to operate as
intended. The fluid barrier 129 may be included on the outside of
the collection container 165 as shown in FIGS. 1A-1C, or it may be
positioned inside the internal chamber 166 of the collection
container 165. Preferably, the fluid barrier 129 may be connected
to a lid 165a of the collection container 165 as shown in FIG.
3E.
[0078] The patient port 167 of collection container 165 may include
a first attachment 195 and a second attachment 194. As shown in the
exemplary embodiments of FIGS. 2A-2C and 3A-3E, the second
attachment 194 may be positioned inside the first attachment 195,
with a web 196 connecting the first attachment 195 and the second
attachment 194. The inner walls of the second attachment 194 form a
sensor channel 171, and the space between the first attachment 195
and the second attachment 194 forms a fluid channel 172. A sensor
tube 190, shown in FIG. 7, may be coupled to collection container
165 and connects the second attachment 194 of the patient port 167
to the sensor port 169 such that air flowing through the sensor
channel 171 of the patient port 167 remains separate from the air
in the internal chamber 166. Although sensor tube 190 is shown as a
separate tube in FIG. 7, sensor tube 190 may be integrally formed
with, or provided as part of, one or more of the collection
container 165, tube 176, or second tube 182 of patient tube set
181.
[0079] The collection container 165 may be formed as a single
component (as shown in the first embodiment, FIGS. 2A-2C), or
preferably, the collection container 165 may be an assembly of a
lid 165a and a base 165b (as shown in the second embodiment, FIG.
3A). If the collection container 165 is an assembly of a lid 165a
and a base 165b, the lid 165a and the base 165b together may
enclose the internal chamber 166. The lid 165a of the second
embodiment of the collection container 165 is shown in FIGS. 3B-3E.
A snap 165c may be included on the lid 165a (see FIG. 3E), which
interlocks with a groove in the base 165b (or alternatively, a snap
in the base 165b may interlock with a groove on the lid 165a) to
prevent the lid 165a and base 165b from being separated during use.
Additional ribs 165d or sealing rings 165e may be included on the
lid 165a or the base 165b to provide a seal between the lid 165a
and the base 165b. The patient port 167, vacuum port 168, and/or
sensor port 169 may be provided on either the lid 165a or the base
165b of the collection container 165. Preferably, the patient port
167, vacuum port 168, sensor port 169, sensor tube 190, and fluid
barrier 129 may all be provided on a lid 165a as shown in FIGS.
3A-3E.
[0080] The collection container 165 may be configured to allow the
patient tube set 181 to be directly connected to the patient port
167 (as shown in the first embodiment, FIGS. 2A-2C), or preferably,
the collection container 165 may be configured to allow the patient
tube set 181 to connect to the patient port 167 via an adapter 300
(as shown in the second embodiment, FIGS. 3A-3E). If the patient
port 167 is configured to connect to the patient tube set 181 via
an adapter 300, one or more pins 167a may be included on an outer
surface of the first attachment 195. The pins 167a may be able to
interlock with one or more slots 329 on the adapter 300.
Wound Dressing
[0081] A wound dressing 123 may include a sterile porous substrate
131, a semipermeable adhesive cover 132, an optional inlet port
134, and a suction port 135. The porous substrate 131 may be
polyurethane foam, polyvinyl alcohol foam, gauze, felt or any other
suitable material. The semipermeable adhesive cover 132 may be made
of a material sold under the trademark Avery Dennison.RTM. or an
adhesive film product made by DermaMed.RTM.. There may be two
openings in the semipermeable adhesive cover 132: an inlet port 134
and a suction port 135. Suction may be applied to the wound
dressing 123 through suction port 135. Irrigation fluid may be
applied to the wound dressing 123 through inlet port 134, as is
further discussed in U.S. Pat. No. 7,608,066, the entirety of which
is hereby incorporated by reference. If irrigation fluid is not
desired, the inlet port 134 may be omitted from the wound dressing
123.
[0082] As shown in FIG. 7, when wound dressing 123 is applied to
the patient, the semipermeable adhesive cover 132 forms a seal with
the patient's skin around the periphery of the wound dressing 123,
thus creating a cavity enclosed by the semipermeable adhesive cover
132 and the wound 124. The periphery of the semipermeable adhesive
cover 132 can be sealed to the patient's skin around the periphery
of the wound. The porous substrate 131 is positioned between the
wound 124 and the semipermeable adhesive cover 132. The porous
substrate 131 may contact the wound 124, but because the surface of
the wound 124 may be uneven, the porous substrate 131 may not
contact the entire surface area of the wound 124.
[0083] When a vacuum is applied to the wound dressing 123 through
the suction port 135, the vacuum is maintained in the cavity. The
porous substrate 131 is provided within the cavity to distribute
vacuum pressure evenly throughout the entire wound bed and prevent
collapse of the cavity. The porous substrate 131 includes
mechanical properties suitable for promoting the formation of
granular tissue and approximating the wound margins. In addition,
when vacuum is applied to wound dressing 123, porous substrate 131
creates micro- and macro-strain at the cellular level of the wound
stimulating the production of various growth factors and other
cytokines and promoting cell proliferation.
Patient Tube Set
[0084] As shown in FIGS. 6-7, the suction port 135 of the wound
dressing 123 may be pneumatically associated with the collection
container 165. Further, the wound pressure sensor 173, solenoid
177, orifice restrictor 178, and adjustable restrictor 200 may be
pneumatically associated with the wound dressing 123 by a patient
tube set 181, typically in combination with one or more of a sensor
tube 190 connecting the patient port 167 and the sensor port 169 of
the collection container 165 and a tube 176 connected to the sensor
port 169. The patient tube set 181 may include a fluid channel 189
that pneumatically associates wound dressing 123 with the internal
chamber 166 of collection container 165 for applying suction to
wound dressing 123, thereby providing a path for fluid to be moved
from the wound 124 to the collection container 165. The patient
tube set 181 may include a sensor channel 188 that pneumatically
associates the wound dressing 123 with one or more of the wound
pressure sensor 173, solenoid 177, orifice restrictor 178, and
adjustable restrictor 200. The fluid channel 189 and sensor channel
188 may be formed from a plurality of tubes.
[0085] The patient tube set 181 may have a tube-within-a-tube
design as shown in FIG. 4, including a first tube 185 and a second
tube 182. Second tube 182 may be positioned inside the lumen of
first tube 185 such that the second tube 182 becomes an inner tube
and the first tube 185 becomes an outer tube. Second tube 182 has a
patient end 183 and a device end 184. First tube 185 has a patient
end 186 and a device end 187.
[0086] The second tube 182 and first tube 185 may have any
cross-sectional shape, including a circle, oval, rectangle, square,
or any other shape, although a substantially circular
cross-sectional shape may be preferred. Preferably, the first tube
185 and the second tube 182 may have the same length. The overall
length of the patient tube set 181 may vary. Patient tube sets 181
connected to the wound dressing 123 may be longer than patient tube
sets 181 used to connect other components. For example, a patient
tube set 181 used to connect the wound dressing 123 with a valve
500 may be longer than a patient tube set 181 used to connect the
valve 500 with an adapter 300.
[0087] The patient tube set 181 may therefore include two channels.
The lumen of the second tube 182 may be a sensor channel 188 which
pneumatically associates the wound dressing 123 with one or more of
the wound pressure sensor 173, solenoid 177, orifice restrictor
178, and adjustable restrictor 200. The space between the inner
surface of the first tube 185 and the outer surface of the second
tube 182 may form a fluid channel 189. The fluid channel 189
pneumatically associates wound dressing 123 with the internal
chamber 166 of collection container 165.
[0088] During use, a patient tube set 181 may be connected to the
suction port 135 of the wound dressing 123 and the patient port 167
of the collection container 165 as shown in FIGS. 6-7. One or both
of the patient end 183 of the second tube 182 and the patient end
186 of the first tube 185 may be connected to the suction port 135
of the wound dressing 123. The device end 184 of the second tube
182 may be connected to the second attachment 194 of the patient
port 167. The device end 187 of the first tube 185 may be connected
to the first attachment 195 of the patient port 167. The fluid
channel 189 of patient tube set 181 may be in communication with
the internal chamber 166 of the collection container 165 via the
fluid channel 172 of the patient port 167. The sensor channel 188
of patient tube set 181 may be in communication with sensor tube
190 via the sensor channel 171 of the patient port 167. Sensor tube
190 communicates with tube 176 via the sensor port 169 of
collection container 165. Therefore, sensor channel 188 of patient
tube set 181 communicates with tube 176, which communicates with
one or more of the wound pressure sensor 173, solenoid 177, orifice
restrictor 178, and adjustable restrictor 200. In the exemplary
embodiment shown in FIG. 7, the sensor channel 188 of the patient
tube set 181 does not open into the internal chamber 166 of the
collection container 165; rather, the sensor channel 188 of the
patient tube set 181 may be in communication with the sensor port
169 of the collection container 165 via sensor tube 190. However,
other configurations are possible in which the sensor channel 188
opens into the internal chamber 166 of the collection container
165.
[0089] The patient tube set 181 may be manufactured using standard
manufacturing techniques. In a preferred embodiment, the first tube
185 and the second tube 182 may be coextruded and joined by a web
193 extending between the inner surface of first tube 185 and the
outer surface of second tube 182. Connecting second tube 182 and
first tube 185 with a web 193 may facilitate the assembly process
by ensuring that the second tube 182 and the first tube 185 remain
connected. Although only one web 193 is shown in FIG. 4, a
plurality of webs 193 may be used. Alternatively, first tube 185
and second tube 182 could be manufactured separately, and the
second tube 182 could be inserted into the lumen of the first tube
185.
[0090] The patient tube set 181 may be made from polyvinylchloride
(PVC), silicone, low density polyethylene (LDPE), polyurethane, or
any other material that is flexible enough to allow the patient
tube set 181 to bend, yet rigid enough that the first tube 185 and
second tube 182 do not collapse if a vacuum is applied within the
tubes. Preferably, the patient tube set 181 may be made from PVC.
Likewise, the thicknesses of the walls of the first tube 185 and
the second tube 182 may be selected such that the tubes are
flexible and compliant while still providing enough structural
integrity that the tubes do not collapse if a vacuum is applied
within the tubes. Preferably, the thickness of the first tube 185
may be about 0.035 inches, and the thickness of the second tube 182
may be about 0.030 inches. The thickness of the web 193 may be
about 0.030 inches.
[0091] Increasing the cross-sectional area of the sensor channel
188 compared to conventional designs may reduce the likelihood of
fluid entering and occluding the sensor channel 188 due to
capillary action. The cross-sectional area of the sensor channel
188 may be calculated based on the dimension of the inner surface
of the second tube 182. For example, the cross-sectional area of a
sensor channel formed by a cylindrical tube may be calculated as
the area of a circle formed by the inner diameter of the tube. In
some embodiments, the sensor channel 188 may have a cross-sectional
area that is at least about 0.75 mm.sup.2. In some embodiments, the
sensor channel 188 may have a cross-sectional area in the range of
between about 0.75 mm.sup.2 and about 7 mm.sup.2. In some
embodiments, the sensor channel 188 may have a cross-sectional area
of at least about 1.75 mm.sup.2. In some embodiments, the sensor
channel 188 may have a cross-sectional area in the range of between
about 1.75 mm.sup.2 and about 7 mm.sup.2. In some embodiments, the
sensor channel 188 may have a cross-sectional area of at least
about 2.5 mm.sup.2. In some embodiments, the sensor channel 188 may
have a cross-sectional area in the range of about 2.5 mm.sup.2 to
about 7 mm.sup.2. In some embodiments, the sensor channel 188 may
have a cross-sectional area in the range of about 2.5 mm.sup.2 to
about 5 mm.sup.2. In a preferred embodiment, the sensor channel 188
may have a cross-sectional area of about 3.25 mm.sup.2. However,
the cross-sectional area of the sensor channel 188 could be
increased until the patient tube set 181 becomes too bulky for
customer acceptance.
[0092] The cross-sectional area of the fluid channel 189 of patient
tube set 181 may be determined by calculating the cross-sectional
area between the inner surface of first tube 185 and the outer
surface of the second tube 182. For example, the cross sectional
area of a fluid channel formed by the space between a cylindrical
first tube and a cylindrical second tube may be determined by
calculating the area of a circle formed by the inner diameter of
the first tube, and subtracting the area of a circle formed by the
outer diameter of the second tube. In some embodiments, the fluid
channel 189 may have a cross-sectional area of at least about 10
mm.sup.2. In some embodiments, the fluid channel 189 may have a
cross-sectional area in the range of about 10 mm.sup.2 to about 30
mm.sup.2. In some embodiments, the fluid channel 189 may have a
cross-sectional area of at least about 15 mm.sup.2. In some
embodiments, the fluid channel 189 may have a cross-sectional area
in the range of about 15 mm.sup.2 to about 20 mm.sup.2. In a
preferred embodiment, the fluid channel 189 may have a
cross-sectional area of about 17.75 mm.sup.2.
[0093] Generally, first tube 185 has a larger cross-sectional area
compared to second tube 182 such that second tube 182 may fit
inside the lumen of the first tube 185 while leaving sufficient
space between the first tube 185 and the second tube 182 to create
a fluid channel 189. In the case where both second tube 182 and
first tube 185 are cylindrical, the inner diameter of first tube
185 may be larger than the outer diameter of the second tube 182.
In some embodiments, the ratio of the cross-sectional area of the
fluid channel 189 to the cross-sectional area of the sensor channel
188 may be in the range of about 4:1 to about 7:1. In some
embodiments, the ratio of the cross-sectional area of the fluid
channel 189 to the cross-sectional area of the sensor channel 188
may be in the range of about 5:1 to about 6:1. In a preferred
embodiment, the ratio of the cross-sectional area of the fluid
channel 189 to the cross-sectional area of the sensor channel 188
may be about 5.5:1.
[0094] In an alternative embodiment of a patient tube set 181' as
shown in FIG. 5, the second tube 182' and first tube 185' may be
positioned side-by-side instead of positioning the second tube
inside the lumen of the first tube. In patient tube set 181', the
lumen of the second tube 182' would form the sensor channel 188',
and the lumen of the first tube 185' would form the fluid channel
189'. In this embodiment, second tube 182' and first tube 185' may
be co-extruded or second tube 182' and first tube 185' may be
manufactured separately. The collection container 165 and wound
dressing 123 may be modified to accommodate the different
configurations of the first tube 185' and second tube 182' of
patient tube set 181'. The patient port 167 of the collection
container 165 and the suction port 135 of the wound dressing 123
may be modified to accommodate the side-by-side tubes. Furthermore,
one or more of the second attachment 194 in the patient port 167,
sensor tube 190, and the sensor port 169 of the collection
container 165 may be eliminated, as the second tube 182' which
forms the sensor channel 188' could connect to tube 176 without the
need for to sensor tube 190 inside the collection container
165.
[0095] Although the first tube and second tube may be positioned
side-by-side, the tube-within-a-tube design of the patient tube set
181 shown in FIG. 4 may be preferred because it may reduce kinking
of the first tube 185 and/or the second tube 182. If the patient
tube set 181 is accidentally bent, crushed, or otherwise deformed,
the force may cause the first tube 185 to deform before the second
tube 182 begins to deform, thereby reducing the changes of blocking
the second tube 182. Furthermore, as the patient tube set 181
deforms, the second tube 182 may act as a support structure that
prevents the first tube 185 from kinking and prevents the fluid
channel 189 from becoming blocked. Therefore, air may flow through
the fluid channel 189 and vacuum may be applied to the wound
dressing 123 even if the patient tube set 181 is accidentally bent,
crushed, or otherwise deformed.
[0096] The first and second tubes of the patient tube set are made
of a semi-rigid material and are able to maintain their shape when
a vacuum is applied by vacuum pumps 105 and 107. Therefore, the
fluid channel 189 and the sensor channel 188 may be substantially
unobstructed because the first and second tubes are able to resist
collapsing when a vacuum is applied by vacuum pumps 105 and
107.
[0097] Patient tube set 181 may include any number of sensor
channels 188. In some embodiments, patient tube set 181 may include
only one sensor channel 188. In other embodiments, patient tube set
181 may include a plurality of sensor channels 188. The plurality
of sensor channels 188 may be positioned inside the lumen of the
first tube 185. The plurality of sensor channels 188 may be formed
from a plurality of second tubes, or they may be formed from a
single extrusion having multiple coaxial lumens. However, providing
a plurality of sensor channels 188 may increase the overall size of
the cross-section of patient tube set 181. Alternatively, if the
overall size of the cross-section of patient tube set 181 is
maintained and a plurality of sensor channels 188 are used, the
cross-sectional area of each of the plurality of sensor channels
188 would decrease, making the sensor channels 188 more likely to
occlude via capillary action. Therefore, it may be advantageous to
use a patient tube set 181 with a single sensor channel 188 in
order to prevent occlusions while minimizing the overall size of
patient tube set 181. Using multiple sensor channels 188 requires
the microcontroller 101 to determine which of the sensor channels
188 is free of occlusions and providing accurate data, and which of
the sensor channels 188 is occluded and therefore providing
inaccurate data. Therefore, if multiple sensor channels 188 are
used, the microcontroller 101 may show an average measurement of
the vacuum pressure applied across all sensor channels 188.
[0098] Standing fluid in any of the tubes connecting pumps 105
and/or 107 to the wound dressing 123 (for example, the fluid
channel 189 of patient tube set 181) may create hydrostatic forces
that cause a difference in the pressure experienced at the wound
dressing 123 (also referred to as the therapeutic pressure)
compared to the pressure being created by pumps 105 and/or 107.
Depending on the position of pumps 105 and/or 107 relative to the
wound, the therapeutic pressure may be increased or decreased
compared to the pressure measured at pumps 105 and/or 107. However,
the system 100 may be able to compensate for these variations in
therapeutic pressure resulting from hydrostatic forces. The
therapeutic pressure may be monitored by wound pressure sensor 173,
and the activity of pumps 105 and/or 107 may be adjusted based on
any pressure fluctuations. This monitoring may occur in real time,
such that pumps 105 and/or 107 may be able to compensate quickly
when the position of the wound changes relative to pumps 105 and/or
107.
[0099] If the vertical position of pumps 105 and/or 107 is higher
than the wound, fluid in any of the tubes connecting pumps 105
and/or 107 to the wound dressing 123 (for example, the fluid
channel 189 of patient tube set 181) may cause the absolute value
of the therapeutic pressure applied to the wound to increase, such
that a weaker vacuum is being applied to the wound. For example, if
the pressure at vacuum pumps 105 and/or 107 is 70 mmHg below
atmospheric pressure, the therapeutic pressure at the wound
dressing 123 may be only 60 mmHg below atmospheric pressure. The
increase in the absolute value of the therapeutic pressure may be
detected by wound pressure sensor 173 and communicated to
microprocessor 102. Control algorithm 150 contains instructions
that will instruct pumps 105 and/or 107 to run, or continue to run,
in order to compensate for the increase in the absolute value of
the therapeutic pressure at the wound.
[0100] Conversely, if the vertical position of pumps 105 and/or 107
is lower than the wound, fluid in any of the tubes connecting pumps
105 and/or 107 to the wound dressing 123 (for example, the fluid
channel 189 of patient tube set 181) may cause the absolute value
of the therapeutic pressure applied to the wound to decrease, such
that a stronger vacuum is being applied to the wound. For example,
if the pressure at vacuum pumps 105 and/or 107 is 70 mmHg below
atmospheric pressure, the therapeutic pressure at the wound
dressing 123 may be 80 mmHg below atmospheric pressure. The
decrease in the absolute value of the therapeutic pressure may be
detected by wound pressure sensor 173. Control algorithm 150
contains instructions that will instruct pumps 105 and/or 107 to
turn off, or run less frequently, in order to compensate for the
decrease in the absolute value of the therapeutic pressure at the
wound. Control algorithm 150 may also contain instructions to open
the solenoid 177 to relieve pressure in order to compensate for the
decrease in the absolute value of the therapeutic pressure at the
wound, if necessary.
Adapter
[0101] An adapter 300, shown in FIGS. 12-14, may be provided on one
or both ends of the patient tube set 181. Preferably, an adapter
300 may be provided on at least the device end of the patient tube
set 181. The adapter 300 may have a first end 313 and a second end
323. The adapter 300 may have at least two ports: a first port 310
at the first end 313, configured to couple to a patient tube set
181, and a second port 320 at the second end 323, configured to
couple to the patient port 167 of the collection container 165
and/or the second or third ports 420, 430 of a y-connector 400
(described below). The first port 310 and the second port 320 may
meet at an interface 330. The second port 320, as described below,
has a female fitting; however, the second port could also have a
male fitting.
[0102] The adapter 300 may have an outer wall 301 and an inner wall
302 connected to the outer wall 301 by one or more webs 303. The
outer wall 301 may have an outer surface 306 and an inner surface
307. The inner wall 302 may have an outer surface 308 and an inner
surface 309. The outer wall 301 may extend along the first port 310
and the second port 320, having a first end 311 at the first port
310 and a second end 321 at the second port 320. The inner surface
307 of the outer wall 301 may have a larger diameter at the second
port 320 and a smaller diameter at the first port 310. A horizontal
ledge 327 may be formed in the outer wall 301 at the interface 330
between the first port 310 and the second port 320, where the inner
surface 307 of the outer wall 301 transitions from the larger
diameter at the second port 320 to the smaller diameter at the
first port 310. The inner wall 302 may extend along the first port
310, having a first end 312 proximate the first end 313 of the
adapter 300, and a second end 322 at the interface 330 between the
first port 310 and the second port 320. The inner wall 302 does not
necessarily extend into the second port 320, and preferably it may
not extend into the second port 320. Preferably, the ledge 327 and
the second end 322 of the inner wall 302 may be coplanar.
[0103] The inner surface 309 of the inner wall 302 may form a
sensor channel 305. The sensor channel 305 may have a first opening
315 on the first end 313 of the adapter 300 and a second opening
325 at the interface 330 between the first port 310 and the second
port 320. The space between the outer surface 308 of the inner wall
302 and the inner surface 307 of the outer wall 301 may form a
fluid channel 304. The fluid channel 304 may have a first opening
314 on the first end 313 of the adapter 300 and a second opening
324 at the interface 330 between the first port 310 and the second
port 320.
[0104] The cross-sections of the inner wall 302 and the outer wall
301 may be circular, elliptical, or various other shapes. However,
in a preferred embodiment, the inner wall 302 and the outer wall
301 may both be substantially circular. More specifically, the
inner surface 307 of the outer wall 301 and the outer surface 308
of the inner wall 302 may have a substantially circular
cross-section. The inner surface 307 of the outer wall 301 and the
outer surface 308 of the inner wall 302 may be substantially
concentric.
[0105] One or more slots 329 may be provided in the outer wall 301
of the second port 320 to receive pins 167a on the first attachment
195 of the patient port 167. One or more notches 328 may also be
provided in the outer wall 301 at the second port 320 to receive
pins 390 on the gasket 380.
[0106] A gasket 380, shown in FIGS. 15A-15B, may be provided with
the adapter 300. The gasket 380 may include an outer sealing rib
381 and an inner sealing rib 382 connected to the outer sealing rib
381 by one or more webs 383. The outer sealing rib 381 may have a
cross-sectional shape similar to the cross-sectional shape of the
ledge 327 on the outer wall 301 of the adapter 300. The inner
sealing rib 382 may have a cross-sectional shape that is similar to
the cross-sectional shape of the second end 322 of the inner wall
302 of the adapter 300. The inner diameter of the inner sealing rib
382 may form a sensor channel 385, and the space between the outer
sealing rib 381 and the inner sealing rib 382 may form a fluid
channel 384. Preferably, the cross-sections of the inner sealing
rib 382 and the outer sealing rib 381 may be substantially
circular, and even more preferably they may be substantially
concentric.
[0107] The gasket 380 may have a first surface and a second surface
opposite the first surface, such that the outer sealing rib 381 has
a first surface 386 and a second surface 387, and the inner sealing
rib 382 has a first surface 388 and a second surface 389. The
gasket 380 may have one or more pins 390 extending outwardly from
the outer sealing rib 381. Preferably, there may be the same number
of pins 390 on the gasket 380 and notches 328 in the adapter 300.
The gasket 380 may be made of any number of materials, including
silicone, thermoplastic elastomers, natural rubber, or any other
elastomeric, compressible, non-porous material. In a preferred
embodiment, the gasket 380 may be made of silicone.
[0108] The gasket 380 may be inserted into the second port 320 of
the adapter 300. The pins 390 on the gasket 380 may be inserted
into the notches 328 in the adapter 300. The first surface 386 of
the outer sealing rib 381 of the gasket 380 may be in contact with
the ledge 327 on the outer wall 301 of the adapter 300. Likewise,
the first surface 388 of the inner sealing rib 382 of the gasket
380 may be in contact with the second end 322 of the inner wall 302
of the adapter 300. The sensor channel 385 of the gasket 380 may be
aligned with the sensor channel 305 of the adapter 300. Each second
opening 324 of the fluid channel 304 of the adapter 300 may be
aligned with a fluid channel 384 in the gasket 380. In order to
provide a continuous path for fluids passing through the fluid
channels 304, 384 of the adapter 300 and the gasket 380, the pins
390 may be positioned on the gasket 380 to allow the webs 383 on
the gasket 380 to substantially overlie the webs 303 on the adapter
300.
[0109] A patient tube set 181 may be connected to the first port
310 of the adapter 300. The device end 187 of the first tube 185
may mate with the outer wall 301 of the adapter 300. Preferably,
the outer surface of the first tube 185 may be in contact with the
inner surface 307 of the outer wall 301. The device end 184 of the
second tube 182 may mate with the inner wall 302 of the adapter
300. Preferably, the inner diameter of the second tube 182 may be
in contact with the outer surface 308 of the inner wall 302. Thus,
the fluid channel 304 of the adapter 300 may be in communication
with the fluid channel 189 of the patient tube set 181. The sensor
channel 305 of the adapter 300 and the sensor channel 385 of the
gasket 380 may be in communication with the sensor channel 188 of
the patient tube set 181.
[0110] The second port 320 of the adapter 300 may be connected to
the patient port 167 of the collection container 165, as shown in
FIGS. 16A-16C. The patient port 167 may be inserted into the outer
wall 301 of the second port 320 of the adapter 300. The pins 167a
on the patient port 167 may be inserted into the slots 329 in the
outer wall 301 of the adapter 300. The gasket 380, positioned in
the second port 320 of the adapter 300, may provide for sealing
engagement between the second port 320 of the adapter 300 and the
patient port 167 of the collection container 165. The ledge 327 on
the outer wall 301 of the adapter 300 may be in sealing engagement
with the first attachment 195 of the patient port 167 via the outer
sealing rib 381 on the gasket 380. The second end 322 of the inner
wall 302 of the adapter 300 may be in sealing engagement with the
second attachment 194 of the patient port 167 via the inner sealing
rib 382 on the gasket 380.
[0111] Thus, if the adapter 300 is connected to both a patient port
167 on a collection container 165 and a patient tube set 181, as
shown in FIGS. 16A-16C, the sensor channel 188 of patient tube set
181 may be in communication with the sensor channel 171 of the
patient port 167, and the fluid channel 189 of patient tube set 181
may be in communication with the fluid channel 172 of the patient
port 167. Using an adapter may be preferred because it may simplify
the user set-up process by allowing the user to connect the adapter
300 to the patient port 167 of the collection container 165, as
shown in FIGS. 16A-16C, instead of individually connecting first
tube 185 and second tube 182 to the patient port 167, as shown in
FIG. 7.
Pump Pressure Sensor
[0112] Pump pressure sensor 109 may be pneumatically associated
with first vacuum pump 105 and an optional second vacuum pump 107
as shown in FIGS. 1A-1C. Pump pressure sensor 109 may be
electrically associated with microcontroller 101 through electrical
cable 110. Pump pressure sensor 109 provides a vacuum-pressure
signal to the microprocessor 102 enabling control algorithm 150 to
monitor the vacuum pressure at the outlet of vacuum pumps 105
and/or 107.
Wound Pressure Sensor
[0113] A wound pressure sensor 173 may be pneumatically associated
with the sensor port 169 of the collection container 165 through a
tube 176 as shown in FIGS. 6-7. Tube 176 may be a single lumen tube
as shown in FIG. 7. Because tube 176 is pneumatically associated
with the wound dressing 123 via one or more of the sensor tube 190
and the sensor channel 188 in the patient tube set 181, the wound
pressure sensor 173 is able to monitor the therapeutic pressure in
the wound dressing 123 more accurately than the pump pressure
sensor 109 can. Wound pressure sensor 173 may be electrically
associated with microcontroller 101 through electrical cable 174
and provides a vacuum-pressure signal to microprocessor 102
enabling control algorithm 150 to monitor the therapeutic pressure
at the wound site.
Solenoid/Valve
[0114] A solenoid 177 and optional orifice restrictor 178 may be
pneumatically associated with the sensor port 169 of the collection
container 165 through tube 176 as shown in FIGS. 1A-1C. If the
orifice restrictor 178 is not provided, solenoid 177 may connected
to tube 176 by "T" connector 175. If the orifice restrictor 178 is
provided, the orifice restrictor 178 may be connected to tube 176
by a "T" connector 175, and vacuum-pressure relief solenoid 177 may
be connected to the orifice restrictor 178. Together, the solenoid
177 and optional orifice restrictor 178 act to relieve pressure in
the wound dressing 123 and in the collection container 165 in the
event of an alarm condition, if the set pressure is decreased
(during intermittent mode, for example), or if power is turned off.
Solenoid 177 may be, for example, one available under the trademark
Pneutronics.RTM., or Air Logic.RTM.. Solenoid 177 is electrically
associated with, and controlled by, microprocessor 102 through
electrical cable 130. Solenoid 177 may be configured to vent vacuum
to atmosphere when the power is turned off, for example. Orifice
restrictor 178, if it is provided, is positioned in line with
solenoid 177 and tube 176 to regulate the rate at which vacuum is
relieved to atmospheric pressure when solenoid 177 is de-energized.
Orifice restrictor 178 is, for example, available under the
trademark Air Logic.RTM..
Adjustable Restrictor
[0115] As shown in FIGS. 1A-1C, an optional adjustable restrictor
200 may be pneumatically associated with tube 176. Two embodiments
of an adjustable restrictor 200 are shown in greater detail in
FIGS. 8-11, and include a cap 210, a body 220, and a porous
material 230. Cap 210 has a base 211 and a flange 213. The base 211
and/or flange 213 of cap 210 has at least one hole 212 that opens
to the atmosphere to allow air to enter the body 220 and create a
controlled air leak in the system 100. Flange 213 has a threaded
portion 214 that engages the body 220. Body 220 includes at least
one tube port 221 and a threaded port 223. The threaded port 223 on
the body 220 engages the threaded portion 214 of the cap 210,
thereby coupling the cap 210 and the body 220.
[0116] The porous material 230 may be positioned between the
threaded port 223 on the body 220 and the base 211 of the cap 210.
The porous material 230 may be compressible. The porous material
230 may have minimal water absorbency (i.e., hydrophobic), which
may prevent the flow rate of the air leak from changing when the
restrictor 200 is exposed to increased or decreased humidity. A
number of common filter materials may be used, including plastic
foams, or synthetic membrane materials such as those used in
cigarette filters. The porous material 230 may be disc-shaped and
may cover the hole 212 on cap 210.
[0117] Air enters the adjustable restrictor 200 at the hole 212 in
the cap 210 to create the air leak. Air then travels through the
porous material 230 before entering the body 220 of the adjustable
restrictor 200 via the threaded port 223. The flow rate of the air
leak may be controlled by compressing or decompressing the porous
material 230. Compressing the porous material 230 by tightening the
connection between the body 220 and the cap 210 decreases the flow
rate of the air leak. Decompressing the porous material 230 by
loosening the connection between the body 220 and the cap 210
increases the flow rate of the air leak.
[0118] In one embodiment shown in FIGS. 8-9, adjustable restrictor
200 may include two tube ports 221. If two tube ports 221 are
provided, adjustable restrictor 200 may be positioned in line with
tube 176, and a "T" connector may not be needed to connect
adjustable restrictor 200 to tube 176. In another embodiment shown
in FIGS. 10-11, adjustable restrictor may include only one tube
port 221 which may be connected to tube 176 by a "T" connector 191
as shown in FIGS. 1A-1C.
[0119] Adjustable restrictor 200 may be designed to create an air
leak that allows air to flow into tube 176. Because sensor channel
188 of the patient tube set 181 is pneumatically associated with
tube 176, the air leak also allows air to flow into the sensor
channel 188 towards wound dressing 123, thereby preventing
occlusions in the sensor channel 188. Any fluid that may have
entered the sensor channel 188 (through capillary action, for
example) is pushed toward the wound dressing 123, and fluid from
the wound dressing 123 is prevented from flowing into the sensor
channel 188 due to the pressure gradient. Furthermore, the air leak
in the sensor channel 188 may cause air to flow into the fluid
channel 189 at the suction port 135 of the wound dressing 123. The
air leak would therefore provide a force that is additive to the
suction force being supplied by pumps 105 and/or 107 to ensure
fluid does not enter sensor channel 188 or remove occlusions from
sensor channel 188. In addition, air from the air leak may flow out
of the patient end 183 of the second tube 182 and into the patient
end 186 of the first tube 185, thereby providing a force that is
additive to the suction force being supplied by pumps 105 and/or
107 to ensure that fluid in the fluid channel 189 would be forced
toward the collection container 165. An advantage of using the
adjustable restrictor 200 is that the air leak may be substantially
uninterrupted when a vacuum is applied to collection container 165
and/or wound dressing 123, such that the air leak may continually
prevent occlusions and help to clear otherwise stationary fluid
from the sensor channel 188 and/or fluid channel 189, instead of
only acting in a reactive manner after an occlusion has formed.
[0120] The flow rate of the air leak should be low enough such that
the air leak does not substantially affect the therapeutic pressure
being applied to the wound dressing 123, causing a leak alarm to be
triggered. The flow rate of the air leak should be low enough that
pumps 105 and/or 107 are able to compensate for the small increase
in the absolute value of the pressure in system 100 resulting from
the leak. Therefore, the therapeutic pressure applied to the wound
dressing 123 may be substantially maintained despite the air leak.
For example, the leak may have a flow rate ranging from 0.05-0.1
liters per minute.
[0121] Alternatively, instead of using the adjustable restrictor
200, an air leak may be created by sporadically opening the
solenoid 177, thereby venting tube 176 to atmosphere such that air
flows from solenoid 177 through tube 176, through one or more of
sensor tube 190 and sensor channel 188 of patient tube set 181
toward wound dressing 123. Any occlusions in the sensor channel 188
of patient tube set 181 may be forced toward wound dressing 123,
and any fluid in the fluid channel 189 of patient tube set 181 may
be forced toward collection container 165. In this case, the
solenoid 177 may function as a time-variable restrictor.
Y-Connector
[0122] A y-connector 400, shown in FIGS. 17-20, may be provided to
allow two patient tube sets 181 connected to two separate wound
dressings 123 to be connected to the same patient port 167 of the
collection container 165. The y-connector 400 may have a first end
413, a second end 423, and a third end 433. The y-connector 400 may
have at least three ports: a first port 410 at the first end 413,
configured to connect to the collection container 165, and second
and third ports 420, 430 at the second and third ends 423, 433,
configured to connect to the two separate wound dressings 123. The
second and third ports 420, 430, as described below, have male
fittings; however they could also have female fittings.
[0123] The y-connector 400 may have an outer wall 401 and an inner
wall 402 connected to the outer wall 401 by one or more webs 403.
The outer wall 401 may have an outer surface 406 and an inner
surface 407. The inner wall 402 may have an outer surface 408 and
an inner surface 409. The outer wall 401 may extend along all three
ports, having a first end 411 at the first end 413 of the
y-connector 400, a second end 421 at the second end 423 of the
y-connector 400, and a third end 431 at the third end 433 of the
y-connector 400. The inner wall 402 may extend along two of the
ports, having a first end 412 at the first end 413 of the
y-connector 400 and a second end 422 at the second end 423 of the
y-connector 400, as shown in FIG. 19.
[0124] The inner surface 409 of the inner wall 402 may form a
sensor channel 405 that extends from a first opening 415 on the
first port 410 to a second opening 425 on the second port 420. A
fluid channel 404 may extend into all three ports, having a first
opening 414 at the first port 410, a second opening 424 at the
second port 420, and a third opening 434 at the third port 430. The
fluid channel 404 in the first port 410 and the second port 420 may
be formed by the space between the outer surface 408 of the inner
wall 402 and the inner surface 407 of the outer wall 401. The fluid
channel 404 in the third port 430 may be formed by the inner
surface 407 of the outer wall 401.
[0125] The cross-sections of the inner wall 402 and the outer wall
401 may be circular, elliptical, or various other shapes. However,
in a preferred embodiment, the inner wall 402 and the outer wall
401 may both be substantially circular. More specifically, the
inner surface 407 of the outer wall 401 and the outer surface 408
of the inner wall 402 may have a substantially circular
cross-section. The inner surface 407 of the outer wall 401 and the
outer surface 408 of the inner wall 402 may be substantially
concentric.
[0126] Any of the first port 410, second port 420, and third port
430 may be designed to connect to a patient tube set 181 directly,
or indirectly using an adapter 300. In a preferred embodiment, the
y-connector 400 may be designed such that the first port 410
directly connects with a patient tube set 181, while the second
port 420 and third port 430 each connect with a patient tube set
181 via an adapter 300.
[0127] A patient tube set 181 may be connected to the first port
410 of the y-connector 400. The patient end 186 of the first tube
185 may mate with the outer wall 401 of the y-connector 400.
Preferably, the outer surface of the first tube 185 may be in
contact with the inner surface 407 of the outer wall 401. The
patient end 183 of the second tube 182 may mate with the inner wall
402 of the y-connector 400. Preferably, the inner surface of the
second tube 182 may be in contact with the outer surface 408 of the
inner wall 402. Thus, the fluid channel 404 of the y-connector 400
may be in communication with the fluid channel 189 of the patient
tube set 181. The sensor channel 405 of the y-connector 400 may be
in communication with the sensor channel 188 of the patient tube
set 181.
[0128] In some embodiments, the second port 420 and third port 430
of the y-connector 400 interface with an adapter 300 connected to a
patient tube set 181. The second port 320 of the adapter 300 may be
connected to the second port 420 or the third port 430 of the
y-connector 400. The second or third port 420, 430 of the
y-connector 400 may be inserted into the outer wall 301 of the
second port 320 of the adapter 300. The second and third ports 420,
430 of the y-connector 400 may each have one or more pins 429, 439
on the outer wall 401 that may be inserted into the slots 329 in
the adapter 300. The gasket 380, positioned in the second port 320
of the adapter 300, may provide for sealing engagement between the
second port 320 of the adapter 300 and the second or third port
420, 430 of the y-connector 400.
[0129] If the adapter 300 is being connected to the second port 420
of the y-connector 400 (which includes an outer wall 401 and an
inner wall 402), the ledge 327 on the outer wall 301 of the adapter
300 may be in sealing engagement with the second end 421 of the
outer wall 401 of the y-connector 400 via the outer sealing rib 381
on the gasket 380. The second end 322 of the inner wall 302 of the
adapter 300 may be in sealing engagement with the second end 422 of
the inner wall 402 of the y-connector 400 via the inner sealing rib
382 on the gasket 380.
[0130] If the adapter 300 is being connected to the third port 430
of the y-connector 400 (which may include an outer wall 401 but not
in inner wall 402), the ledge 327 on the outer wall 301 of the
adapter 300 may be in sealing engagement with the second end 431 of
the outer wall 401 of the y-connector 400 via the outer sealing rib
381 on the gasket 380. The second end 322 of the inner wall 302 of
the adapter 300 may not be in sealing engagement with the
y-connector 400.
[0131] When patient tube sets 181 are connected to each of the
first, second, and third ports 410, 420, 430 of the y-connector
400, the fluid channels 189 of the patient tube sets 181 connected
to the second and third ports 420, 430 communicate with the fluid
channel 404 of the y-connector 400. The sensor channel 188 of the
patient tube set 181 connected to the second port 420 of the
y-connector 400 (into which the inner wall 402 extends)
communicates with the sensor channel 405 of the y-connector 400.
However, the sensor channel 188 of the patient tube set 181
connected to the third port 430 of the y-connector 400 (into which
the inner wall 402 does not extend) communicates with the fluid
channel 404 of the y-connector 400.
[0132] When using a y-connector 400, it is preferable that the
sensor channel 405 extends from the first port 410 to only one of
the second port 420 or the third port 430. As described above and
shown in FIGS. 17-20, the sensor channel 405 may extend from the
first port 410 to the second port 420, but not to the third port
430. If the sensor channel 405 of the y-connector 400 also extended
into the third port 430, the wound pressure sensor 173 may only
detect a blockage when the patient tube sets 181 connected to the
second and third ports 420, 430 of the y-connector 400 were both
occluded. If a blockage or occlusion occurred in only one of the
patient tube sets 181 connected to the second and third ports 420,
430 of the y-connector 400, the wound pressure sensor 173 would
still detect the vacuum from the unoccluded patient tube set 181,
and the blockage alarm would not be triggered. Therefore, it may be
advantageous for the y-connector 400 to have a sensor channel 405
extending between only the first port 410 and the second port 420.
In this configuration, the wound pressure sensor 173 may detect a
blockage if the patient tube set 181 connected to the second port
420 of the y-connector 400 was occluded and the patient tube set
181 connected to the third port 430 of the y-connector 400 was not
occluded, or if the patient tube sets 181 connected to the second
and third ports 420, 430 of the y-connector 400 were both
occluded.
[0133] Alternatively, instead of providing the y-connector 400 and
the adapter 300 as separate components, they may be formed as a
single component. In this case, patient tube sets 181 may be
connected to the second and third ports 420, 430, and the first
port 410 may be integrated with the second port 320 of the adapter
300. The outer wall 301 of the second port 320 of the adapter 300
may be continuous with the outer wall 401 of the first port 410 of
the y-connector 400, and the inner wall 302 of the second port 320
of the adapter 300 may be continuous with the inner wall 402 of the
first port 410 of the y-connector 400. Potential methods for
manufacturing a combined y-connector 400 and adapter 300 may
include 3D printing or molding.
Valve
[0134] At certain points during use, it may be desirable to close
the fluid channel 189 and/or the sensor channel 188 of the patient
tube set 181, thereby preventing vacuum pressures from being
transmitted along the channel. For example, it may be desirable to
close the fluid channel 189 and sensor channel 188 when replacing a
collection container 165 while maintaining the wound dressing 123
over the wound, or when troubleshooting leaks and blockages in the
system 100. As discussed above, the patient tube set 181 may be
resistant to kinking, which may beneficially prevent the fluid
channel 189 from becoming occluded if the patient tube set 181 is
accidentally bent, crushed, or otherwise deformed. However, as a
result, the user may not be able to close the fluid channel 189
using conventional means such as a clamp.
[0135] Therefore, in order to close the fluid channel 189 and/or
the sensor channel 188, a valve 500 may be connected in-line with
the patient tube set 181 to allow the user to occlude the fluid
channel 189 and/or the sensor channel 188 when desired. The valve
500 may include a valve housing 510, a slide switch 550, a valve
seat 570, a first indicator band 501, and a second indicator band
502.
[0136] The valve housing 510 may have a longitudinal axis 516 and a
transverse axis 515 substantially perpendicular to the longitudinal
axis 516. The valve housing 510 may have a first longitudinal end
512, a second longitudinal end 513, a first transverse end 517, and
a second transverse end 518. A channel 514 may extend from the
first longitudinal end 512 toward the second longitudinal end 513
along the longitudinal axis 516. One or more grooves 519 may extend
longitudinally along the inner surface of the channel 514, starting
at the second longitudinal end 513. Preferably, the one or more
grooves 519 do not extend all the way to the first longitudinal end
512 of the housing 510.
[0137] A first port 520 and a second port 530 may be included on
the valve housing 510. The first port 520 and second port 530 may
be provided at the first transverse end 517 and second transverse
end 518 of the valve housing 510, respectively. The first and
second ports 520, 530 may each include an outer wall 521, 531 and
an inner wall 522, 532 connected to the outer wall 521, 531 by a
web 523, 533. A web 523, 533 may extend between the inner wall 522,
532 and the outer wall 521, 531 along a line substantially parallel
to the longitudinal axis 516 of the valve housing 510. The inner
surface of the inner wall 522, 532 may form a sensor channel 525,
535. A fluid channel 524, 534 may be formed by the space between
the outer surface of the inner wall 522, 532 and the inner surface
of the outer wall 521, 531. Preferably, the first and second ports
520, 530 may both be substantially parallel with the transverse
axis 515.
[0138] The first and second ports 520, 530 may be connected to
patient tube sets 181 by mating the outer wall 521, 531 with the
first tube 185 and the inner wall 522, 532 with the second tube
182.
[0139] The valve housing 510 may alternatively be formed together
with an adapter 300 to form a single component. In this case, a
patient tube set 181 may be connected to the first port 520, and
the second port 530 of the valve housing 510 may be connected with
the second port 320 of the adapter 300. The outer wall 301 of the
second port 320 of the adapter 300 may be continuous with the outer
wall 531 of the second port 530 of the valve housing 510, and the
inner wall 302 of the second port 320 of the adapter 300 may be
continuous with the inner wall 532 of the second port 530 of the
valve housing 510. Potential manufacturing techniques may include
3D printing or molding.
[0140] The valve 500 may include a slide switch 550, shown in FIGS.
32-33. The slide switch 550 may have a longitudinal axis 556 and a
transverse axis 555 substantially perpendicular to the longitudinal
axis 556. The slide switch 550 may be elongated along the
longitudinal axis 556, having a first end 552 and a second end 553.
A channel 554 may extend through the slide switch 550 along the
transverse axis 555. A first annular groove 557 may be included on
the slide switch 550 proximate the first end 552, and a second
annular groove 558 may be included on the slide switch 550
proximate the second end 553. One or more pins 559 may be included
proximate the second end 553 of the slide switch 550.
[0141] The valve 500 may also include a valve seat 570, shown in
FIGS. 34-37. The valve seat 570 may have a longitudinal axis 576
and a transverse axis 575 substantially perpendicular to the
longitudinal axis 576. The valve seat 570 may be elongated along
the longitudinal axis 576, having a first longitudinal end 572 and
a second longitudinal end 573. The valve seat 570 may also be
elongated along the transverse axis 575, having a first transverse
end 577 and a second transverse end 578. The valve seat 570 may be
made of any number of materials, including silicone, thermoplastic
elastomers, natural rubber, or any other elastomeric, compressible,
non-porous material. In a preferred embodiment, the valve seat 570
may be made of silicone. Additionally, although the valve seat 570
and the slide switch 550 are described as separate components, they
may also be manufactured as a single part (for example, by
overmolding the valve seat 570 onto the slide switch 550).
[0142] A sensor channel 585 may extend through the valve seat 570
from the first transverse end 577 to the second transverse end 578.
Preferably, the sensor channel 585 may extend through the valve
seat 570 in a direction substantially parallel to the transverse
axis 575. The sensor channel 585 may have a first opening 586 on
the first transverse end 577 of the valve seat 570 and a second
opening 587 on the second transverse end 578 of the valve seat 570.
A preferred embodiment of a valve seat 570 is shown in FIGS. 34-37,
and includes one sensor channel 585; however, one or more sensor
channels 585 may be included.
[0143] One or more fluid channels 584 may extend through the valve
seat 570 from the first transverse end 577 to the second transverse
end 578. Preferably, the one or more fluid channels 584 may extend
through the valve seat 570 in a direction substantially parallel to
the transverse axis 575. The fluid channel 584 may have a first
opening 581 on the first transverse end 577 of the valve seat 570
and a second opening 582 on the second transverse end 578 of the
valve seat 570. A preferred embodiment of a valve seat 570, shown
in FIGS. 34-37, includes two fluid channels 584; however, one or
more fluid channels 584 may be included.
[0144] Two indicator bands 501, 502 may be included in the valve
500. These indicator bands 501, 502 provide a visual indication of
when the valve 500 is open, and when the valve 500 is closed. As
shown in FIGS. 21-23 and 25-27, the indicator bands 501, 502 may be
separate components (for example, o-rings) inserted into the
annular grooves 557, 558 on the slide switch 550. However, the
indicator bands do not need to be separate components from the
slide switch 550. For example, the indicator bands 501, 502 could
be strips that are painted on appropriate sections of the slide
switch 550. As shown in FIGS. 21-23, when the valve 500 is in the
open position, the second indicator band 502 may be visible to the
user. Optionally, the second indicator band 502 may be green in
color to indicate that the valve 500 is open. As shown in FIGS.
25-27, when the valve 500 is in the closed position, the first
indicator band 501 may be visible to the user. Optionally, the
first indicator band 501 may be red in color to indicate that the
valve 500 is closed.
[0145] To assemble the valve 500, the valve seat 570 may be
inserted into the channel 554 of the slide switch 550. The
transverse axis 575 of the valve seat 570 may be substantially
parallel with the transverse axis 555 of the slide switch 550. A
first indicator band 501 may be positioned in the first annular
groove 557, and a second indicator band 502 may be positioned in
the second annular groove 558. The slide switch 550 may then be
inserted into channel 514 of the valve housing 510. The
longitudinal axis 516 of the valve housing 510 may be substantially
parallel with the longitudinal axis 556 of the slide switch 550 and
the longitudinal axis 576 of the valve seat 570. The transverse
axis 515 of the valve housing 510 may be substantially parallel
with the transverse axis 555 of the slide switch 550 and the
transverse axis 575 of the valve seat 570
[0146] In operation, the valve 500 may have two positions: an open
position and a closed position. The valve 500 may be moved between
the open position and the closed position by moving the valve seat
570 longitudinally relative to the valve housing 510. The valve 500
may be moved to the open position by moving the valve seat 570
longitudinally toward the first longitudinal end 512 of the valve
housing 510. When the valve 500 is in the open position, the second
indicator band 502 may be located outside the channel 514 on the
valve housing 510 such that it is visible to the user. The valve
500 may be moved to the closed position by moving the valve seat
570 longitudinally toward the second longitudinal end 513 of the
valve housing 510. When the valve 500 is in the closed position,
the first indicator band 501 may be located outside the channel 514
on the valve housing 510 such that it is visible to the user.
[0147] When the valve 500 is in the open position, as shown in
FIGS. 21-24, the sensor channel 585 of the valve seat 570 may be in
communication with the sensor channel 525 of the first port 520 and
the sensor channel 535 of the second port 530 of the valve housing
510. Therefore, a vacuum applied to the sensor channel 525 of the
first port 520 may be transmitted to the sensor channel 535 of the
second port 530, and vice versa. Likewise, the fluid channel 584 of
the valve seat 570 may be in communication with the fluid channel
524 of the first port 520 and the fluid channel 534 of the second
port 530. Therefore, a vacuum applied to the fluid channel 524 of
the first port 520 may be transmitted to the fluid channel 534 of
the second port 530, and vice versa.
[0148] When the valve 500 is in the closed position, as shown in
FIGS. 25-28, the sensor channel 585 of the valve seat 570 is not in
communication with at least one of the sensor channel 525 of the
first port 520 and the sensor channel 535 of the second port 530 of
the valve housing 510. Therefore, the valve seat 570 may block a
vacuum applied to the sensor channel 525 of the first port 520 from
being transmitted to the sensor channel 535 of the second port 530,
and vice versa. Likewise, the fluid channel 584 of the valve seat
570 is not in communication with at least one of the fluid channel
524 of the first port 520 and the fluid channel 534 of the second
port 530. Therefore, the valve seat 570 may block a vacuum applied
to the fluid channel 524 of the first port 520 from being
transmitted to the fluid channel 534 of the second port 530, and
vice versa.
[0149] Preferably, the valve 500 may be designed to allow the fluid
channels 524, 534 to communicate with one another, and the sensor
channels 525, 535 to communicate with one another, while preventing
cross-communication between the fluid channels 524, 534 and the
sensor channels 525, 535. In order to prevent cross-communication,
the openings 586, 587 of the sensor channel 585 and the openings
581, 582 of the fluid channel 584 may be carefully positioned on
the valve seat 570. A line starting at any point on the first
opening 586 of the sensor channel 585 and extending substantially
parallel to the longitudinal axis 576 should not pass through or
over the first opening 581 of a fluid channel 584, and a line
starting at any point on the first opening 581 of a fluid channel
584 and extending substantially parallel to the longitudinal axis
576 should not pass through or over the first opening 586 of the
sensor channel 585. Similarly, a line starting at any point on the
second opening 587 of the sensor channel 585 and extending
substantially parallel to the longitudinal axis 576 should not pass
through or over the second opening 582 of a fluid channel 584, and
a line starting at any point on the second opening 582 of a fluid
channel 584 and extending substantially parallel to the
longitudinal axis 576 should not pass through or over the second
opening 587 of the sensor channel 585. When the valve 500 is moved
between the open position and the closed position by moving the
valve seat 570 along its longitudinal axis 576 relative to the
valve housing 510, the fluid channels 524, 534 and the sensor
channels 525, 535 may be prevented from cross-communicating.
[0150] The valve 500 may be designed with features that prevent the
valve seat 570 and slide switch 550 from being inadvertently
removed from the channel 514 of the housing, and also provide
tactile feedback to the user. The first end 552 of the slide switch
550 may be larger than the opening of the channel 514 on the first
longitudinal end 512 of the housing 510. As the slide switch 550
and valve seat 570 are moved toward the second longitudinal end 513
of the housing 510, the first end 552 of the slide switch 550 hits
the first longitudinal end 512 of the housing 510, which prevents
the valve seat 570 and slide switch 550 from being removed from the
second longitudinal end 513 of the housing 510. Additionally, each
pin 559 on the slide switch 550 is inserted into a groove 519 in
the channel 514 of the housing 510. As the slide switch 550 and
valve seat 570 are moved toward the first longitudinal end 512 of
the housing 510, the pin 559 hits the end of the groove 519, which
prevents the slide switch 550 and valve seat 570 from being removed
from the first longitudinal end 512 of the housing 510.
Assembly
[0151] A wound dressing subassembly 601, shown in FIG. 38, may be
provided. The wound dressing subassembly 601 may include a wound
dressing 123, a valve 500, an adapter 300, and two patient tube
sets 181. One patient tube set 181 may be connected to the fluid
port 135 of the wound dressing 123 at one end and the first port
520 of the housing 510 of the valve 500 at the other end. Another
patient tube set 181 may be connected to the second port 530 of the
housing 510 of the valve 500 at one end and the first port 310 of
the adapter 300 at the other end. The valve 500 and one patient
tube set 181 may be omitted from the wound dressing subassembly 601
if desired, in which case a single patient tube set 181 may connect
the fluid port 135 of the wound dressing 123 to the first port 310
of the adapter 300. The fluid channel 304 in the adapter 300, the
fluid channel 189 in the patient tube set 181, and optionally the
fluid channels 524, 534, 584 in the valve 500 may form one
continuous fluid channel (when the valve 500, if included, is in
the open position). The sensor channel 305 in the adapter 300, the
sensor channel 188 in the patient tube set 181, and optionally the
sensor channels 525, 535, 585 in the valve 500 may form one
continuous fluid channel (when the valve 500, if included, is in
the open position). If only one wound dressing 123 is being
connected to the patient port 167 of the collection container 165,
the second port 320 of the adapter 300 of the wound dressing
subassembly 601 may be connected to the patient port 167 of the
collection container 165.
[0152] Alternatively, if a plurality of wound dressings 123 are
being connected to the patient port 167 of the collection container
165, a y-connector subassembly 602, shown in FIG. 39, may be
provided. The y-connector subassembly 602 may include a y-connector
400, an adapter 300, and a patient tube set 181. One end of the
patient tube set 181 may be connected to the first port 410 of the
y-connector 400. Another end of the patient tube set 181 may be
connected to the first port 310 of the adapter 300. The fluid
channel 304 in the adapter 300, the fluid channel 189 in the
patient tube set 181, and the fluid channel 404 in the y-connector
400 may form one continuous fluid channel. The sensor channel 305
in the adapter 300, the sensor channel 188 in the patient tube set
181, and the sensor channel 405 in the y-connector 400 may form one
continuous sensor channel. Optionally, a valve 500 could be placed
in-line with the patient tube set 181; however, it may be preferred
to place the valve 500 on the wound dressing subassembly 601
instead.
[0153] The y-connector subassembly 602 may be connected to two
wound dressing subassemblies 601 during use. Each of the second
and/or third ports 420, 430 of the y-connector 400 may be connected
to the second port 320 of the adapter 300 on each wound dressing
subassembly 601. The second port 320 of the adapter 300 on the
y-connector subassembly 602 may be connected to the patient port
167 on the collection container 165. The sensor channel of the
wound dressing subassembly 601 connected to the second port 420 of
the y-connector 400 may be in communication with the sensor channel
171 on the patient port 167 of the collection container 165, while
the fluid channel may be in communication with the fluid channel
172 on the patient port 167 of the collection container 165. Both
the fluid channel and the sensor channel of the wound dressing
assembly 601 connected to the third port 430 of the y-connector 400
may be in communication with the fluid channel 172 on the patient
port 167 of the collection container 165.
[0154] There may be two pneumatic pathways leading away from the
wound dressing 123. A first pneumatic pathway pneumatically may
associate the wound dressing 123 with one or more of the wound
pressure sensor 173, the adjustable restrictor 200, the solenoid
177, and the optional orifice restrictor 178 via a series of tubes
(for example, the second tube 182 of the patient tube set 181,
sensor tube 190, and tube 176.) In an exemplary embodiment, the
wound dressing 123 may be in fluid communication with the sensor
channel 171 on the patient port 167 of the collection container 165
via the sensor channel 188 of the patient tube set 181. The sensor
channel 171 on the patient port 167 may be in fluid communication
with the sensor port 169 via sensor tube 190. The sensor port 169
of collection container 165 may be in fluid communication with one
or more of the wound pressure sensor 173, the adjustable restrictor
200, the solenoid 177, and the optional orifice restrictor 178 via
tube 176. Although the second tube 182 of the patient tube set 181,
sensor tube 190, and tube 176 are described as separate components,
one or more of these tubes may be formed as a single tube. In the
exemplary embodiments, vacuum is not applied to the cavity of the
wound dressing 123 through the sensor channel 188 of the patient
tube set 181, so fluid does not flow from the wound dressing 123
into the sensor channel 188.
[0155] A second pneumatic pathway allows vacuum to be applied to
the wound dressing by pneumatically associating the wound dressing
123 with the internal chamber 166 of the collection container 165
and ultimately with the vacuum pumps 105 and/or 107 and the pump
pressure sensor 109. The wound dressing 123 may be in fluid
communication with the internal chamber 166 of the collection
container 165 via the fluid channel 189 of the patient tube set 181
and the fluid channel 172 of the patient port 167 of collection
container 165. The internal chamber 166 of the collection container
165 may be in fluid communication with the vacuum pumps 105 and/or
107 via tube 115 which is connected to the vacuum port 168 of the
collection container 165.
[0156] The first pneumatic pathway and the second pneumatic pathway
may be in fluid communication at the suction port 135 of the wound
dressing 123. Therefore, a suction force may be applied to the
sensor channel 188 at the suction port 135 of the wound dressing
123 which helps to draw any fluid in the sensor channel 188 back
toward the wound dressing 123, and eventually through the fluid
channel 189. As such, the vacuum is applied to the cavity of the
wound dressing 123 through the fluid channel 189 of the patient
tube set 181, causing fluid in the wound dressing 123 to
preferentially flow into the fluid channel 189 instead of flowing
into the sensor channel 188. The air leak, optionally created by
the adjustable restrictor 200, provides a force that is additive to
the vacuum. While fluid is being drawn away from the wound dressing
123 by the vacuum in the fluid channel 189 of the patient tube set
181, the air leak in the sensor channel 188 prevents fluid from
entering the sensor channel 188, pushes any fluid that may enter
the sensor channel 188 back towards the wound dressing 123, and
pushes fluid in the wound dressing 123 into fluid channel 189. The
additive forces generated by the air leak and the vacuum help to
keep the sensor channel 188 clear of fluid, which ensures that the
pressure measured by the wound pressure sensor 173 accurately
reflects the therapeutic pressure applied at the wound dressing
123. The additive forces also advantageously prevent standing fluid
and occlusions from occurring in the fluid channel 189, which may
affect the therapeutic pressure provided at the wound dressing
123.
Operation
[0157] When a user is ready to use the system 100, a wound dressing
123 may be applied to the wound site. The wound dressing 123 may be
connected to the collection container 165 via patient tube set 181.
The internal chamber 166 of the collection container 165 may be
pneumatically associated with vacuum pumps 105 and/or 107 via tube
115. A vacuum pressure may be created by vacuum pumps 105 and/or
107. This vacuum pressure may be applied to the internal chamber
166 of the collection container 165 via tube 115. The fluid channel
189 of patient tube set 181 may pneumatically associate the
internal chamber 166 of the collection container 165 with the
suction port 135 of the wound dressing 123. Thus, the fluid channel
189 of patient tube set 181 may be pneumatically associated with
vacuum pumps 105 and/or 107, thereby allowing vacuum pressure
created by vacuum pumps 105 and/or 107 to be applied in the cavity
of the wound dressing 123.
[0158] During use, it may be desirable to monitor the pressure
being applied at various points in the system 100. The pump
pressure sensor 109 may measure the vacuum pressure created by
vacuum pumps 105 and/or 107. However, the pressure measured by the
pump pressure sensor 109 may not be equal to the therapeutic
pressure applied to the cavity of the wound dressing 123 for
several reasons. Standing fluid in the fluid channel 189 of the
patient tube set 181 may create hydrostatic forces that increase or
decrease the therapeutic pressure of the vacuum being applied to
the cavity of the wound dressing 123, depending on the position of
the wound relative to vacuum pumps 105 and/or 107. The patient tube
set 181 may become kinked, crushed, or otherwise deformed, which
may decrease the therapeutic pressure. The patient tube set 181 may
become completely blocked with viscous fluids and/or wound exudate,
which may decrease the therapeutic pressure. Therefore, the pump
pressure sensor 109 may not necessarily be an accurate indication
of the therapeutic pressure applied to the wound dressing 123. A
pressure sensor pneumatically associated with the internal chamber
166 of the collection container 165 may have the same disadvantage,
because the pressure in the internal chamber 166 of the collection
container 165 may not be equal to the therapeutic pressure applied
to the cavity of the wound dressing 123.
[0159] However, the system 100 may measure the therapeutic pressure
applied at the wound dressing 123 using a wound pressure sensor 173
pneumatically associated with the cavity of the wound dressing 123
through at least one of tube 176, sensor tube 190, and the sensor
channel 188 of the patient tube set 181. Fluid is not intended to
travel inside the sensor channel 188, and therefore pressure
differentials between the wound pressure sensor 173 and the cavity
of the wound dressing 123 may be avoided because there is no
standing fluid (or minimal amounts of standing fluid) in sensor
channel 188 to create hydrostatic forces.
[0160] One advantage of the system 100 is that it enables the
microcontroller 101 to detect standing fluid and occlusions in the
patient tube set 181. The microcontroller 101 may compare the
pressures measured by the wound pressure sensor 173 and the pump
pressure sensor 109. If there is a discrepancy between the two
measurements, control algorithm 150 may contain instructions that
alert the user and/or cause the system 100 make adjustments to
ensure that the intended therapeutic pressure is being applied at
the wound dressing 123.
[0161] If the absolute pressure measured by the wound pressure
sensor 173 is greater than the absolute pressure measured by the
pump pressure sensor 109, the control algorithm 150 may contain
instructions that instruct pumps 105 and/or 107 to run, or continue
to run, in order to compensate for the increase in the absolute
value of the therapeutic pressure at the wound.
[0162] If the absolute pressure measured by the wound pressure
sensor 173 is less than the absolute pressure measured by the pump
pressure sensor 109, control algorithm 150 may contain instructions
that will instruct pumps 105 and/or 107 to turn off, or run less
frequently, in order to compensate for the decrease in the absolute
value of the therapeutic pressure at the wound. Control algorithm
150 may also contain instructions to open the solenoid 177 to
relieve pressure in order to compensate for the decrease in the
absolute value of the therapeutic pressure at the wound, if
necessary.
[0163] The system 100 may use the above steps to try to resolve
differences between the pressure measured by the wound pressure
sensor 173 and the pressure measured by the pump pressure sensor
109. However, if these steps are unable to resolve the difference,
the control algorithm 150 may contain instructions to active a
blockage alarm (optionally, via the display 160). The user would
then know to inspect the patient tube set 181 for kinking,
crushing, standing fluid, or other blockages.
[0164] In addition to being able to detect occlusions and standing
fluid and take reactive measures to correct the therapeutic
pressure at the wound dressing 123, the system 100 also prevents
kinking and crushing of the patient tube set 181, and prevents
blockages and standing fluid from occurring in the patient tube set
181 in the first place. As discussed above, the tube-within-a-tube
design for the patient tube set 181 may reduce the likelihood that
crushing or bending the patient tube set 181 will cause the tube to
kink and become occluded. Furthermore, the air leak, optionally
created by the adjustable restrictor 200 and/or solenoid 177, may
provide a force that is additive to the vacuum pressures, helping
to move fluid along the fluid channel 189 of the patient tube set
181. Standing fluid and occlusions in the patient tube set 181 are
not only unsightly, but they may cause the user to think that the
system is not working.
[0165] Generally speaking, the patient port 167 of the collection
container 165, the second port 320 of the adapter 300, and the
second and third ports 420, 430 of the y-connector 400 may each
have either a male fitting or a female fitting. Preferably, the
patient port 167 of the collection container 165 and the second and
third ports 420, 430 of the y-connector 400 may have a male
fitting, and the second port 320 of the adapter 300 may have a
female fitting. Alternatively, the patient port 167 of the
collection container 165 and the second and third ports 420, 430 of
the y-connector 400 may have a female fitting, and the second port
320 of the adapter 300 may have a male fitting.
Examples
Samples
[0166] Three types of tube sets (Example 1, Comparison A, and
Comparison B) were tested to determine the crushing force required
to occlude the fluid channel of each tube set. As shown in FIG. 42,
Example 1 tube sets 710c were dual-lumen tube sets having a
tube-within-a-tube design according to certain embodiments
described in the present disclosure. The tube sets of Example 1 had
a first tube 713c and a second tube 714c, and the second tube was
positioned in the lumen of the first tube. The lumen of the second
tube formed the sensor channel 712c, and the space between the
inner surface of the first tube and the outer surface of the second
tube formed the fluid channel 711c.
[0167] Unlike Example 1, neither Comparison A tube sets nor
Comparison B tube sets included a first tube and a second tube,
where the second tube was positioned in the lumen of the first
tube. As shown in FIG. 40, Comparison A tube sets 710a were
multi-lumen tube sets manufactured by KCl.RTM.. Comparison A tube
sets had one fluid channel 711a and four sensor channels 712a
parallel to, but located entirely outside of, the fluid channel.
Comparison A tube sets included one tube 715a--the fluid channel
was the lumen of the tube, and the sensor channels extended inside
the tube wall, along the length of the tube. As shown in FIG. 41,
Comparison B tube sets 710b were single-lumen tube sets
manufactured by Cardinal Health.RTM.. Comparison B tube sets had a
single tube 716b, and the lumen of the tube formed a fluid channel
711b. Comparison B tube sets did not include a sensor channel.
[0168] Test Set-Up:
[0169] In order to determine the crushing force required to occlude
the fluid channel of each sample tube set, test equipment was
configured to a) apply and measure a crushing force to the sample
tube set, and b) objectively determine whether the fluid channel
was occluded at any given point in time. The test configurations
described below and shown in FIGS. 43-46 were used in these
Examples; however, various test configurations with additional,
fewer, or different components may be used to achieve the same
results.
[0170] A mechanical testing machine 740 was used to apply and
measure a crushing force to the sample tube set 710 as shown in
FIGS. 43-44. The mechanical testing machine used in these
experiments was a Zwick Z005 testing machine, but any device
capable of applying and measuring compression forces could be used
instead. FIGS. 43-44 refer to a sample tube set 710 which could
represent any one of Comparison A tube set 710a, Comparison B tube
set 710b, or Example 1 tube set 710c depending on the sample being
tested.
[0171] As shown in FIGS. 43-44, the mechanical testing machine 740
had a sample platform 741 and two jaws 742 that were moveably
connected to the sample platform 741 by a support structure (not
shown in FIGS. 43-44). A driving feature (also not shown in FIGS.
43-44) causes the jaws 742 to travel in a direction perpendicular
to the sample platform 741. A thin plate 743 having a thickness of
1.27 mm was clamped between the jaws 742. The thin plate 743 was
substantially perpendicular to the sample platform 741 of the
mechanical testing machine. The sample tube set 710 was positioned
on the sample platform 741 such that the thin plate 743 was
substantially perpendicular to the length of the sample tube set
710, as shown in FIGS. 43-44. A load cell (not shown in FIGS.
43-44) on the mechanical testing machine measured the crushing
force generated as the jaws 742 traveled toward the sample platform
741, causing the thin plate 743 to crush the sample tube set
710.
[0172] The test configurations 700, 700' shown in FIGS. 45-46
allowed the user to objectively determine whether the fluid channel
in the sample tube set was occluded. In each test configuration
700, 700', a pump unit 720 applied a vacuum to the device end of
the fluid channel of the sample tube set, and the patient end of
the fluid channel was open to atmosphere. A pressure sensor 730 was
used to monitor the pressure in the fluid channel. When the fluid
channel was not occluded, the pressure along the entire fluid
channel was equal to atmospheric pressure. However, when the fluid
channel was crushed to the point of occlusion, the absolute
pressure in the device end of the fluid channel decreased,
signaling to the user that the fluid channel was occluded.
[0173] Test configuration 700 (shown in FIG. 45) was used to test
Example 1 tube sets, and included a pump unit 720, a pressure
sensor 730, a collection container 165, a sample tube set 710c, a
T-connector 725, and pneumatic tubing 701. The pump unit 720 was a
Cardinal Health.TM. NPWT PRO pump unit, but the test configuration
could be modified to use any vacuum source. The pressure sensor 730
was a digital manometer, but any device capable of measuring vacuum
pressures could be used instead. The collection container 165 was
discussed above and is shown in FIGS. 3A-3E.
[0174] In test configuration 700, the sample tube set 710c was
connected to the patient port 167 of the collection container 165,
allowing the fluid channel 711c of the sample tube set 710c to
communicate with the internal chamber 166 of the collection
container 165. The sensor port 169 of the collection container 165
was connected to a sensor port 722 on the pump unit 720. The vacuum
port 168 of the collection container 165 was connected to a
T-connector 725, and the T-connector 725 was connected to a vacuum
port 721 on the pump unit 720 and the pressure sensor 730.
Therefore, the pressure sensor 730 was in pneumatic communication
with the internal chamber 166 of the collection container 165 and
the fluid channel of sample tube set 710c.
[0175] Test configuration 700' (shown in FIG. 46) was used to test
Comparison A tube sets and Comparison B tube sets (collectively
shown in FIG. 46 as 710'). Test configuration 700' included a pump
unit 720, a pressure sensor 730, a collection container 765, a
sample tube set 710', a T-connector 725, and pneumatic tubing 701.
The pump unit 720 and pressure sensor 730 were the same as those
used in test configuration 700. The collection container 765 used
in test configuration 700' was similar to collection container 165.
Collection container 765 also included a patient port 767, a vacuum
port 768, and a sensor port 769. The vacuum port 768 and sensor
port 769 of collection container 765 were similar to the vacuum
port 168 and sensor port 169 of collection container 165. However,
there were two differences between collection container 165 and
collection container 765: 1) the patient port 167 of collection
container 165 was a dual-lumen port having a fluid channel and a
sensor channel, whereas the patient port 767 of collection
container 765 was a single-lumen port having only a fluid channel,
and 2) the collection container 165 included a sensor tube 190 that
connected the sensor port 169 to the sensor channel of the patient
port 167, whereas collection container 765 did not include a sensor
tube, and the sensor port 769 was instead open to the internal
chamber of the collection container 765.
[0176] In test configuration 700', the fluid channel of the sample
tube set 710' was connected to the patient port 767 of the
collection container 765, allowing the fluid channel of the sample
tube set 710' to communicate with the internal chamber of the
collection container 765. The sensor port 769 of the collection
container 765 was connected to a sensor port 722 on the pump unit
720. The vacuum port 768 of the collection container 765 was
connected to a T-connector 725, and the T-connector 725 was
connected to a vacuum port 721 on the pump unit 720 and the
pressure sensor 730. Therefore, the pressure sensor 730 was in
pneumatic communication with the internal chamber of the collection
container 765 and the fluid channel of sample tube set 710'.
[0177] Based on the set-up described above, when testing Comparison
A tube sets and Example 1 tube sets, the vacuum source and the
pressure sensor were pneumatically associated with the fluid
channel, and were not pneumatically associated with the sensor
channels. When testing Comparison B tube sets, the vacuum source
and the pressure sensor were pneumatically associated with the
fluid channel. Therefore, the pressure sensor 730 measured the
pressure in the fluid channel 711a, 711b, 711c of the sample tube
set 710a, 710b, 710c for all samples.
[0178] Test Procedure:
[0179] The pressure sensor was calibrated to produce a reading of 0
mmHg when exposed to standard atmospheric pressure (which
corresponds to an absolute pressure of 760 mmHg). Vacuum pressures
(which have an absolute pressure less than 760 mmHg) resulted in a
negative reading on the pressure sensor. For example, when exposed
to an absolute pressure of 610 mmHg, the pressure sensor would
produce a reading of -150 mmHg. For the purposes of this
discussion, pressures will be described as absolute pressures.
[0180] The vacuum source was turned on and set to generate a vacuum
having an absolute pressure of 610 mmHg. When the vacuum source was
running but no load was placed on the tube set (crushing force=0
N), the pressure sensor would measure an absolute pressure in the
fluid channel that was approximately equal to atmospheric pressure
(760 mmHg) because the patient end of the tube set was open to
atmosphere.
[0181] The thin plate was moved toward the sample platform at a
rate of 0.03 mm/second, thereby applying a crushing force to the
tube set. As the crushing force increased, the fluid channel began
to close, and the absolute pressure in the fluid channel decreased
from atmospheric pressure to a value that was less than atmospheric
pressure. The test was stopped when the absolute pressure in the
fluid channel was equal to or less than 625 mmHg (indicating that
the fluid channel had been occluded), and the peak crushing force
was recorded. Three sample tube sets of each of Comparison A,
Comparison B, and Example 1 were tested, and each sample was tested
at three locations along the length of the tube set. The results
are shown in Table 1.
TABLE-US-00001 TABLE 1 Crushing force required to occlude fluid
channel of sample tube sets Crushing Force (N) required to occlude
Sample Location fluid channel No. No. Comparison A Comparison B
Example 1 1 1 40.36 24.22 120.00 2 39.80 25.55 119.39 3 40.01 26.70
128.10 Sample 40.06 25.49 122.50 Average 2 1 40.46 25.12 128.79 2
38.02 25.85 105.16 3 44.43 25.16 121.91 Sample 40.97 25.38 118.62
Average 3 1 49.40 24.49 141.32 2 47.05 25.93 122.41 3 47.06 22.64
125.42 Sample 47.84 24.35 129.72 Average OVERALL 42.95 25.07 123.61
AVERAGE
[0182] As shown in Table 1, the average crushing force required to
occlude the fluid channel of Example 1 tube sets (123.61 N) was
significantly higher than the average crushing force required to
occlude the fluid channel of Comparison A tube sets (42.95 N) and
the average crushing force required to occlude the fluid channel of
Comparison B tube sets (25.07 N). A two sample unpaired student's
t-test at a 95% confidence level (.alpha.=0.05) was used to
individually compare Example 1 tube sets to Comparison A tube sets,
and Example 1 tube sets to Comparison B tube sets. The force
measurements measured at the three locations on the same sample
were averaged, and this sample average was treated as one data
point (n=3 for each of Comparison A, Comparison B, and Example 1).
These t-tests showed that the crushing forces required to occlude
the fluid channels of Example 1 tube sets was statistically
significantly higher than the crushing forces required to occlude
the fluid channels of Comparison A tube sets and Comparison B tube
sets (the p-value for each comparison was less than 0.0001).
[0183] The foregoing description is provided to enable any person
skilled in the art to practice the various example implementations
described herein. Various modifications to these variations will be
readily apparent to those skilled in the art, and the generic
principles defined herein may be applied to other implementations.
All structural and functional equivalents to the elements of the
various illustrious examples described throughout this disclosure
that are known or later come to be known to those of ordinary skill
in the art are expressly incorporated herein by reference.
* * * * *