U.S. patent application number 17/489465 was filed with the patent office on 2022-01-20 for reduced-pressure treatment systems with reservoir control.
The applicant listed for this patent is KCI Licensing, Inc.. Invention is credited to Christopher Brian LOCKE, Benjamin Andrew PRATT, Aidan Marcus TOUT.
Application Number | 20220016330 17/489465 |
Document ID | / |
Family ID | |
Filed Date | 2022-01-20 |
United States Patent
Application |
20220016330 |
Kind Code |
A1 |
PRATT; Benjamin Andrew ; et
al. |
January 20, 2022 |
REDUCED-PRESSURE TREATMENT SYSTEMS WITH RESERVOIR CONTROL
Abstract
A reduced-pressure system for delivering reduced pressure for
medical purposes to a desired site and to receive fluids in one
instance includes a reservoir having an interior space operable to
contain the fluids. A reduced-pressure delivery conduit is placed
in fluid communication with the interior space for delivering the
reduced pressure to the desired site. A source conduit and a
pressure sensor conduit are placed in fluid communication with the
interior space. A pressure sensor is placed in fluid communication
with the pressure sensor conduit. A reduced-pressure source is
placed in fluid communication with the source conduit. A
reduced-pressure control unit is associated with the pressure
sensor and the reduced-pressure source and is operable to receive
pressure data from the pressure sensor and supply data from the
reduced-pressure source and to determine when a
reservoir-full/blockage condition exists. Other systems and methods
are presented.
Inventors: |
PRATT; Benjamin Andrew;
(Poole, GB) ; LOCKE; Christopher Brian;
(Bournemouth, GB) ; TOUT; Aidan Marcus;
(Alderbury, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KCI Licensing, Inc. |
San Antonio |
TX |
US |
|
|
Appl. No.: |
17/489465 |
Filed: |
September 29, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16157755 |
Oct 11, 2018 |
11154651 |
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17489465 |
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14148320 |
Jan 6, 2014 |
10124097 |
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16157755 |
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|
13724876 |
Dec 21, 2012 |
8652111 |
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14148320 |
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12537797 |
Aug 7, 2009 |
8366691 |
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|
13724876 |
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61087377 |
Aug 8, 2008 |
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International
Class: |
A61M 1/00 20060101
A61M001/00 |
Claims
1. A method for controlling a reduced-pressure source using a
microprocessor, comprising: sending a first signal from the
microprocessor in response to a condition being met; wherein the
condition is met when an absolute value associated with a second
signal does not reach a threshold value in response to a third
signal being increased for a specified time period; wherein the
reduced-pressure source is configured to be shut down in response
to receiving the first signal; wherein the second signal is
indicative of a level of reduced pressure within a reservoir; and
wherein the third signal is indicative of a supply rate of reduced
pressure from the reduced-pressure source.
2. The method of claim 1, further comprising sending a fourth
signal from the microprocessor in response to the condition being
met.
3. The method of claim 2, wherein a speaker is configured to
produce an audible alarm in response to receiving the fourth
signal.
4. The method of claim 2, wherein an indicator light is configured
to produce a visual warning in response to receiving the fourth
signal.
5. The method of claim 2, wherein a display screen is configured to
produce a visual warning in response to receiving the fourth
signal.
6. The method of claim 1, wherein the condition is indicative of a
blockage condition.
7. The method of claim 6, wherein the blockage condition is
indicative of a full reservoir.
8. The method of claim 1, wherein the second signal is correlated
to power supplied to the reduced-pressure source.
9. The method of claim 1, wherein the second signal is correlated
to current supplied to the reduced-pressure source.
10. The method of claim 1, wherein the second signal is indicative
of a valve opening on the reduced-pressure source.
11. A control unit for controlling a reduced-pressure source, the
controller configured to: send a first signal to in response to a
condition being met; wherein the condition is met when an absolute
value associated with a second signal does not reach a threshold
value in response to a third signal being increased for a specified
time period; wherein the reduced-pressure source is configured to
be shut down in response to receiving the first signal; wherein the
second signal is indicative of a level of reduced pressure within a
reservoir; and wherein the third signal is indicative of a supply
rate of reduced pressure from the reduced-pressure source.
12. The control unit of claim 11, wherein the controller is further
configured to send a fourth signal in response to the condition
being met.
13. The control unit of claim 12, wherein the fourth signal causes
a speaker to produce an audible alarm.
14. The control unit of claim 12, wherein the fourth signal causes
an indicator light to produce a visual warning.
15. The control unit of claim 12, wherein the fourth signal causes
a display screen to produce a visual warning.
16. The control unit of claim 11, wherein the condition is
indicative of a blockage condition.
17. The control unit of claim 16, wherein the blockage condition is
indicative of a full reservoir.
18. The control unit of claim 11, wherein the second signal is
correlated to power supplied to the reduced-pressure source.
19. The control unit of claim 11, wherein the second signal is
correlated to current supplied to the reduced-pressure source.
20. The control unit of claim 11, wherein the second signal is
indicative of a valve opening on the reduced-pressure source.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 16/157,755, filed Oct. 11, 2018, which is a
continuation of U.S. patent application Ser. No. 14/148,320, filed
Jan. 6, 2014, now U.S. Pat. No. 10,124,097, which is a divisional
of U.S. patent application Ser. No. 13/724,876, filed Dec. 21,
2012, now U.S. Pat. No. 8,652,111 which is a divisional of U.S.
patent application Ser. No. 12/537,797, filed Aug. 7, 2009, now
U.S. Pat. No. 8,366,691, which claims the benefit, under 35 USC
.sctn. 119(e), of the filing of U.S. Provisional Patent Application
No. 61/087,377, filed Aug. 8, 2008, which are incorporated herein
by reference for all purposes.
BACKGROUND
[0002] The present invention relates generally to medical treatment
systems and devices, and more particularly, to reduced-pressure
treatment systems with reservoir control.
[0003] The treatment of wounds is at times problematic. Proper care
is required to minimize the possibility of infection and,
preferably, to help stabilize the wound. Proper care typically
involves keeping the wound clean and dry. Exudate from the wound is
often removed and held away from the wound.
[0004] In recent times, reduced pressure has been used to help
treat wounds and remove fluids including exudate. In many
instances, reduced pressure has been applied with a negative
pressure device that includes a foam pad placed on or in the wound
and fluidly coupled to a reduced-pressure source. The
reduced-pressure source typically has involved a vacuum pump that
when activated delivers reduced pressure to the foam pad such that
fluid is removed from the wound through the foam pad and
transported through a tube to a fluid reservoir, such as a
canister. The reservoir collects and holds the fluids removed from
operation of the treatment system. When the reservoir is full of
removed fluid, the reservoir is emptied and reengaged to the system
or replaced. Efforts have been made to alert the patient when the
reservoir is full.
BRIEF SUMMARY
[0005] Shortcomings with certain aspects of reduced-pressure
treatment systems and systems for alerting a patient that a
reservoir is full are addressed by the present invention as shown
and described in a variety of illustrative embodiments herein.
According to an illustrative embodiment, a reduced-pressure
treatment system for treating a tissue site on a patient includes a
manifold member for placing proximate the tissue site, an
over-drape for providing a fluid seal over the manifold member and
the patient, and a reduced-pressure subsystem for delivering
reduced pressure to the over-drape. The reduced-pressure subsystem
includes a reservoir having an interior space operable to contain
fluids, a reduced-pressure delivery conduit in fluid communication
with the interior space for delivering reduced pressure to the
over-drape, a source conduit in fluid communication with the
interior space, a pressure sensor conduit in fluid communication
with the interior space, and a pressure sensor in fluid
communication with the pressure sensor conduit. The
reduced-pressure subsystem further includes a reduced-pressure
source in fluid communication with the source conduit and operable
to deliver reduced pressure to the source conduit, and a
reduced-pressure control unit associated with the pressure sensor
and reduced-pressure source. The reduced-pressure control unit is
operable to receive pressure data from the pressure sensor and
supply data from the reduced-pressure source and to determine when
a reservoir-full/blockage condition exists.
[0006] According to another illustrative embodiment, a
reduced-pressure system for providing reduced pressure and for
receiving fluids includes a reservoir having an interior space
operable to contain the fluids, a reduced-pressure delivery conduit
in fluid communication with the interior space for delivering
reduced pressure, a source conduit in fluid communication with the
interior space, and a pressure sensor conduit in fluid
communication with the interior space. The reduced-pressure system
further includes a pressure sensor in fluid communication with the
pressure sensor conduit and a reduced-pressure source in fluid
communication with the source conduit and operable to deliver
reduced pressure to the source conduit. The reduced-pressure system
also includes a reduced-pressure control unit associated with the
pressure sensor and reduced-pressure source that is operable to
receive pressure data from the pressure sensor and supply data from
the reduced-pressure source and to determine when a
reservoir-full/blockage condition exists.
[0007] According to another illustrative embodiment, a
reduced-pressure system includes a reservoir housing that forms an
interior space and a reduced-pressure source for delivering reduced
pressure. The reduced-pressure source is fluidly coupled to the
interior space of the reservoir and is operable to deliver a
reduced pressure to the interior space. The reduced-pressure source
is responsive to a control signal. The reduced-pressure system
further includes a supply sensor for measuring a supply rate of
reduced pressure and operable to develop a signal I indicative of
the supply rate, a pressure sensor conduit fluidly coupled to the
interior space, and a pressure sensor in fluid communication with
the pressure sensor conduit. The pressure sensor is operable to
develop a signal P indicative of a pressure level in the pressure
sensor conduit proximate the pressure sensor. The reduced-pressure
system further includes a reduced-pressure control unit coupled to
the supply sensor, pressure sensor, and the reduced-pressure
source. The reduced-pressure control unit is operable to receive
signal I from the supply sensor and signal P from the pressure
sensor and to adjust the control signal to cause the
reduced-pressure source to provide a desired pressure to the
reservoir and to shutdown when the reservoir is full.
[0008] According to another illustrative embodiment, a method of
detecting a fill status of a reservoir for use in treating a
patient with a reduced-pressure treatment system includes the steps
of: generating reduced pressure in fluid communication with the
reduced-pressure treatment system, applying the reduced pressure to
a tissue site, collecting fluid from the tissue site in the
reservoir, and monitoring a pressure within the reservoir. The
method further includes terminating the application of reduced
pressure when the pressure in the reservoir decreases below a
selected absolute value for specified time interval. The reservoir
has a pressure sensor conduit in fluid communication with the
reservoir and a supply conduit in fluid communication with the
reservoir. The step of monitoring the pressure within the reservoir
includes monitoring the pressure within the pressure sensor
conduit.
[0009] According to another illustrative embodiment, a method of
manufacturing a reduced-pressure system includes the steps of
forming a reservoir having an interior space operable to contain
fluids and fluidly coupling a reduced-pressure delivery conduit to
the interior space. The reduced-pressure delivery conduit is for
delivering a reduced pressure to a delivery site. The method of
manufacturing further includes fluidly coupling a source conduit to
the interior space, fluidly coupling a pressure sensor conduit to
the interior space, and fluidly coupling a pressure sensor to the
pressure sensor conduit. The method may also include providing a
reduced-pressure source responsive to a control signal, coupling
the reduced-pressure source to the source conduit, and providing a
reduced-pressure control unit. The reduced-pressure control unit is
operable to receive pressure data from the pressure sensor and
supply data from the reduced-pressure source and to determine when
a reservoir-full/blockage condition exists.
[0010] Other features and advantages of the illustrative
embodiments will become apparent with reference to the drawings and
detailed description that follow.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] A more complete understanding of the system, method, and
apparatus of the present invention may be obtained by reference to
the following Detailed Description when taken in conjunction with
the accompanying Drawings wherein:
[0012] FIG. 1 is a schematic, perspective view of an illustrative
embodiment of a reduced-pressure treatment system with reservoir
control with a portion shown in cross section;
[0013] FIG. 2A is a schematic, diagram with a portion in
cross-section of one illustrative embodiment of a reduced-pressure
treatment system with reservoir control;
[0014] FIG. 2B and 2C are schematic, elevational, cross-sectional
views of a portion of the reduced-pressure system of FIG. 2A;
[0015] FIG. 3 is a representative graph presenting illustrative
operational parameters of a reduced-pressure treatment system
according to one illustrative embodiment;
[0016] FIG. 4 is a schematic diagram of an illustrative embodiment
of a reduced-pressure control unit; and
[0017] FIG. 5 is an illustrative flow chart of one possible
approach to the logic incorporated into a reduced-pressure control
unit in one illustrative embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0018] In the following detailed description of the preferred
embodiments, reference is made to the accompanying drawings that
form a part hereof, and in which is shown by way of illustration
specific preferred embodiments in which the invention may be
practiced. These embodiments are described in sufficient detail to
enable those skilled in the art to practice the invention, and it
is understood that other embodiments may be utilized and that
logical structural, mechanical, electrical, and chemical changes
may be made without departing from the spirit or scope of the
invention. To avoid detail not necessary to enable those skilled in
the art to practice the invention, the description may omit certain
information known to those skilled in the art. The following
detailed description is, therefore, not to be taken in a limiting
sense, and the scope of the present invention is defined only by
the appended claims.
[0019] Referring to FIG. 1, an illustrative embodiment of a
reduced-pressure treatment system 100 for treating a tissue site
106, e.g., a wound 104. The tissue site 106 may be the bodily
tissue of any human, animal, or other organism, including bone
tissue, adipose tissue, muscle tissue, dermal tissue, vascular
tissue, connective tissue, cartilage, tendons, ligaments, or any
other tissue. Unless otherwise indicated, as used herein, "or" does
not require mutual exclusivity. The wound 104 may take numerous
possible shapes and degrees, but in this illustrative example is
shown as a linear wound, such as from a surgical procedure, through
epidermis 108, dermis 110, and into a portion of the subcutaneous
tissue 112. In this example, the reduced-pressure treatment system
100 is shown applied on top of the epidermis 108 and over the wound
104, but it is to be appreciated that the reduced-pressure
treatment system 100 could be used with an open wound and could be
placed, in part, below the epidermis in a wound bed. The
reduced-pressure treatment system 100 may include a manifold member
114, a sealing subsystem 116, and a reduced-pressure subsystem 126.
The reduced-pressure treatment system 100 may be built for
relatively less money than conventional systems, achieve greater
mechanical reliability, and operate in multiple orientations
without false alarms.
[0020] In one illustrative embodiment, the manifold member 114 is
made from a porous and permeable foam-like material and, more
particularly, a reticulated, open-cell polyurethane or polyether
foam that allows good permeability of wound fluids while under a
reduced pressure. One such foam material that has been used is the
VAC.RTM. Granufoam.RTM. Dressing available from Kinetic Concepts
Inc. (KCI) of San Antonio, Tex. Any material or combination of
materials may be used for the manifold material provided that the
manifold material is operable to distribute the reduced pressure.
The term "manifold" as used herein generally refers to a substance
or structure that is provided to assist in applying reduced
pressure to, delivering fluids to, or removing fluids from a tissue
site. A manifold typically includes a plurality of flow channels or
pathways that distribute fluids provided to and removed from the
area of tissue around the manifold. The plurality of flow pathways
may be interconnected. Examples of manifolds may include, without
limitation, devices that have structural elements arranged to form
flow channels, cellular foam, such as open-cell foam, porous tissue
collections, and liquids, gels and foams that include or cure to
include flow channels. The manifold material may also be a
combination or layering of materials. For example, a first manifold
layer of hydrophilic foam may be disposed adjacent to a second
manifold layer of hydrophobic foam to form the manifold member
114.
[0021] The reticulated pores of the Granufoam.RTM. material, that
are in the range of about 400 to 600 microns, are helpful in
carrying out the manifold function, but again other materials may
be used. A material with a higher, or lower, density (smaller pore
size) than Granufoam.RTM. material may be desirable in some
situations. The manifold member 114 may also be a reticulated foam
that is later felted to thickness of about 1/3 its original
thickness. Among the many possible materials, the following may be
used: Granufoam.RTM. material or a Foamex technical foam
(www.foamex.com). In some instances it may be desirable to add
ionic silver to the foam in a microbonding process or to add other
substances to the manifold member such as antimicrobial agents. The
manifold member 114 could be a bio-absorbable or bio-inert material
or an anisotropic material.
[0022] The sealing subsystem 116 includes an over-drape 118, or
drape. The over-drape 118 covers the manifold member 114 and
extends past a peripheral edge 121 of the manifold member 114 to
form a drape extension 120. The drape extension 120 may be sealed
against the patient's epidermis 108 by a sealing apparatus 122,
such as a pressure-sensitive adhesive 124. The sealing apparatus
122 may take numerous forms, such as an adhesive sealing tape, or
drape tape or strip; double-sided drape tape; adhesive 124; paste;
hydrocolloid; hydrogel; or other sealing device. If a tape is used,
the tape may be formed of the same material as the over-drape 118
with a pre-applied, pressure-sensitive adhesive. The
pressure-sensitive adhesive 124 may be applied on a second,
patient-facing side of drape extension 120. The pressure-sensitive
adhesive 124 provides a substantially fluid seal between the
over-drape 118 and the epidermis 108 of the patient. "Fluid seal,"
or "seal," means a seal adequate to hold reduced pressure at a
desired site given the particular reduced-pressure subsystem
involved. Before the over-drape 118 is secured to the patient, the
pressure-sensitive adhesive 124 may have removable strips covering
the adhesive 124.
[0023] The over-drape 118 may be an elastomeric material that
provides a fluid seal. The sealing member may, for example, be an
impermeable or semi-permeable, elastomeric material. "Elastomeric"
means having the properties of an elastomer and generally refers to
a polymeric material that has rubber-like properties. More
specifically, most elastomers have elongation rates greater than
100% and a significant amount of resilience. The resilience of a
material refers to the material's ability to recover from an
elastic deformation. Examples of elastomers may include, but are
not limited to, natural rubbers, polyisoprene, styrene butadiene
rubber, chloroprene rubber, polybutadiene, nitrile rubber, butyl
rubber, ethylene propylene rubber, ethylene propylene diene
monomer, chlorosulfonated polyethylene, polysulfide rubber,
polyurethane, EVA film, co-polyester, and silicones. Specific
examples of sealing member materials include a silicone drape, 3M
Tegaderm.RTM. drape, acrylic drape such as one available from Avery
Dennison, or an incise drape.
[0024] The reduced-pressure subsystem 126 includes a
reduced-pressure source 128, which may take many different forms.
The reduced-pressure source 128 provides reduced pressure as a part
of the reduced-pressure treatment system 100. The reduced-pressure
source 128 may be any device for supplying a reduced pressure, such
as a vacuum pump, wall suction, or other source. While the amount
and nature of reduced pressure applied to a tissue site will
typically vary according to the application, the reduced pressure
will typically be between -5 mm Hg and -500 mm Hg and more
typically between -100 mm Hg and -300 mm Hg.
[0025] As used herein, "reduced pressure" generally refers to a
pressure less than the ambient pressure at a tissue site 106 that
is being subjected to treatment. In most cases, this reduced
pressure will be less than the atmospheric pressure at which the
patient is located. Alternatively, the reduced pressure may be less
than a hydrostatic pressure at the tissue site. Reduced pressure
may initially generate fluid flow in the manifold member 114,
reduced-pressure conduit 148, and proximate the tissue site 106. As
the hydrostatic pressure around the tissue site 106 approaches the
desired reduced pressure, the flow may subside, and the reduced
pressure may be maintained. Unless otherwise indicated, values of
pressure stated herein are gauge pressures. The reduced pressure
delivered may be constant or varied (patterned or random) and may
be delivered continuously or intermittently. Although the terms
"vacuum" and "negative pressure" may be used to describe the
pressure applied to the tissue site, the actual pressure applied to
the tissue site may be more than the pressure normally associated
with a complete vacuum. Consistent with the use herein, an increase
in reduced pressure or vacuum pressure typically refers to a
relative reduction in absolute pressure.
[0026] In the illustrative embodiment of FIG. 1, the
reduced-pressure source 128 is shown having a reservoir region 131,
or canister region, with windows 138 providing a visual indication
of the level of fluid within reservoir 150. An interposed membrane
filter, such as hydrophobic or oleophobic filter, may be
interspersed between a reduced-pressure delivery conduit, or
tubing, 148 and the reduced-pressure source 128.
[0027] The reduced-pressure source 128 has a display 130, which may
include an alarm light or information indicator 132, a battery
light or indicator 134, a reservoir full/blocked light or indicator
136. The reduced-pressure source 128 may also include a power
switch 140 and a speaker 142 for providing an audible alarm. In
some embodiments, a keypad for entry of desired pressure or other
information may also be provided. As described further below, the
reduced-pressure subsystem 126 includes a reduced-pressure control
unit analogous to a reduced-pressure control unit 260 in FIG.
2A.
[0028] The reduced pressure developed by the reduce-pressure source
128 is delivered through the reduced-pressure delivery conduit 148
to a reduced-pressure interface 144, which may be an elbow port
146. In one illustrative embodiment, the port 146 is a TRAC.RTM.
technology port available from Kinetic Concepts Inc. of San
Antonio, Texas. The reduced-pressure interface 144 allows the
reduced pressure to be delivered to the sealing subsystem 116 and
realized within an interior portion of sealing subsystem 116. In
this illustrative embodiment, the elbow port 146 extends through
the over-drape 118 and into the manifold member 114.
[0029] In operation, the reduced-pressure treatment system 100 is
applied to treat the tissue site 106, e.g., the wound 104, by
placing the manifold member 114 approximate wound 104, providing a
fluid seal over the manifold member 114 and a portion of the
epidermis 108 by using the sealing subsystem 116, attaching the
reduced-pressure subsystem 126 and activating the reduced-pressure
subsystem 126. The reduced-pressure subsystem 126 delivers reduced
pressure to the manifold member 114, which distributes the reduced
pressure to the wound site 106 as well as potentially providing
other beneficial effects, such as a closing force in some
applications when a closing dressing bolster is used. The
reduced-pressure subsystem 126 may be used with a wound application
as shown, and the reduced-pressure subsystem 126 may also be used
with percutaneous applications, such as applying reduced pressure
to a bone, tissue, or other wound site. In utilizing the
reduced-pressure treatment system 100, the reduced-pressure
treatment system 100 will continue to apply reduced pressure until
the reservoir, or canister, 150 of the reduced-pressure source 128
becomes full. Because, it is desirable to minimize any breaks in
the treatment, the status of the reservoir 150 may be visually
monitored through the windows 138, but it is desirable to have the
reduced-pressure subsystem 126 automatically alert the patient when
the reservoir 150 is full or when a blockage has occurred such that
reduced pressure is no longer being delivered. It may also be
desirable to shutdown the reduced-pressure source 128 when the
reservoir 150 is full or blocked.
[0030] Referring now primarily to FIG. 2A, an illustrative
embodiment of a reduced-pressure system 200 which may be used as
the reduced-pressure subsystem 126 of the reduced-pressure
treatment system 100 in FIG. 1 is presented. The reduced pressure
is provided by the reduced-pressure system 200 and ultimately
delivered by a reduced-pressure delivery conduit 222 for medical
purposes to a delivery site, e.g., reduced-pressure interface 144
and tissue site 106 of FIG. 1. The reduced-pressure system 200
includes a reservoir 224 formed with a reservoir housing 226 that
defines an interior space 230. The reservoir 224 may be any unit
for holding fluids, such as a canister, bag, impervious envelope,
etc. Proximate a top portion 228 (for the orientation shown with
the unit standing parallel to the gravitational field), a number of
ports may be formed through the reservoir housing 226. For example,
a delivery-conduit port 232, a source port 234, and a sensor port
240 may be formed through the reservoir housing 226. The
reduced-pressure delivery conduit 222 interfaces with the
reduced-pressure delivery conduit port 232 such that the
reduced-pressure delivery conduit 222 may be placed in fluid
communication, or fluidly coupled, with the interior space 230. A
source conduit 236 interfaces with the source port 234 to allow the
source conduit 236 to be in fluid communication, or fluidly
coupled, with the interior space 230. Similarly, a pressure sensor
conduit 242 interfaces with the sensor port 240 to allow the
pressure sensor conduit 242 to be placed in fluid communication, or
fluidly coupled, with the interior space 230. While the sensor port
240 is shown slightly below the source port 234, it should be noted
that these ports 234, 240 may be on the same vertical level in
other embodiments.
[0031] The reduced-pressure delivery conduit 222 delivers reduced
pressure for medical purposes and receives fluid, such as exudate,
that enter into the interior space 230. A number of filters, e.g.,
hydrophobic filters or odor filters, may be desired on the conduits
222, 236, and 242. For example, the source conduit 236 is shown
with a first filter unit 238, and the pressure sensor conduit 242
is shown with a second filter unit 244. While filter units 238 and
244 are shown as single units, it is to be understood that a
plurality of filters may make up each filter unit.
[0032] The pressure sensor conduit 242 provides fluid communication
from the interior space 230 to a pressure sensor 246. The pressure
sensor 246 may be any device (or devices) that is capable of
sensing the pressure in the pressure sensor conduit 242 and
developing a responsive single which may be analog or digital, and
delivering the signal by a communication conduit 247 to the
reduced-pressure control unit 260. In an alternative embodiment,
the pressure sensor 246 may be or include a pneumatic regulator
that is coupled to a reduced-pressure source, e.g., a vacuum pump
248, regulated wall suction, mechanical device, or other reduced
pressure apparatus.
[0033] The source conduit 236 is in fluid communication with the
interior space 230 and is also in fluid communication with a
reduced-pressure source, e.g., the vacuum pump 248. The vacuum pump
248 works to generate the reduced pressure that is introduced into
the source conduit 236. In the illustrative embodiment, the vacuum
pump 248 is electrically powered as indicated by a first power line
252. The first power line 252 is electrically coupled to a pump
power supply 250. The pump power supply 250 may be a battery supply
or a conditioned power from another source. A portion of the first
power line 252 may include a power sensor 254 and a current control
unit 256. The power sensor 254 may be any device that is used to
determine the amount of power being supplied to the vacuum pump
248. For example, the power sensor 254 may be a current sensor
operable to produce a current signal or supply data signal I. More
generally, the supply data signal may be produced that provides
information on the rate of delivery or attempted delivery of
reduced pressure. In one illustrative embodiment, the supply data
signal may be the current supplied to a vacuum pump. In another
illustrative embodiment, the supply data signal may be a signal
indicative of a valve opening on a regulated wall suction unit.
Whether a current signal, other power data, or supply data
developed by power sensor 254 or other sensor that measures a
signal correlated to a supply rate, the resulting signal I is
delivered by a communication conduit 255 to the reduced-pressure
control unit 260.
[0034] The reduced-pressure control unit 260 contains circuitry or
a microprocessor that controls functions within the
reduced-pressure system 200. The reduced-pressure control unit 260
receives a pressure signal P from the communication conduit 247 and
supply data, e.g. signal I, from the communication conduit 255,
which is coupled to a sensor, e.g., the power sensor 254. The
reduced-pressure control unit 260 determines if the interior space
230 of the reservoir 224 is substantially full or if a conduit 222,
236, 242 is blocked. If the reduced-pressure control unit 260
determines that the interior space 230 is full or conduits blocked,
the reduced-pressure control unit 260 may send an alarm to a
speaker 216 as well as providing an alarm signal to a display unit
204. The reduced-pressure control unit 260 may also develop a pump
control signal PC that is delivered by a communication conduit 261
to the current control unit 256 and may be used to increase the
power to the vacuum pump 248 or to reduce or stop the vacuum pump
248. Similarly, if a different reduced pressure source is used, a
control signal may be used to adjust the reduced-pressure source.
In alternative embodiments, it may be desirable to provide other
inputs or data to the reduced-pressure control unit 260, such as a
temperature input that may be used to predict the viscosity of the
fluid being captured within the interior space 230 and to further
adjust parameters for determining when the reservoir is full, such
as the time interval used.
[0035] Referring now primarily to FIGS. 2A, 2B, 2C, in operation,
the reduced-pressure system 200 is initially activated and has
unblocked conduits 222, 236, 242 and an empty interior space 230.
Reduced pressure is delivered to the interior space 230 and is
transmitted to the reduced-pressure delivery conduit 222 and to a
desired site. FIG. 2A shows this initial state with the reservoir
224 empty. As the reduced pressure is delivered for treatment of a
tissue site, e.g., a wound, on a patient, various fluids are
typically received through the reduced-pressure delivery conduit
222 and are delivered into the interior space 230 where the fluid
collects. FIG. 2B shows the fluid 258 collecting in a bottom
portion of the interior space 230. The reduced-pressure control
unit 260 continues to operate the vacuum pump 248 and pressure
sensor 246 continues to monitor the pressure experienced within the
pressure sensor conduit 242 which typically corresponds to the
pressure within the interior space 230. The reduced pressure is
monitored to determine that the pressure is within a desired range
or at least above a threshold. When, however, the fluid 258 fills
or substantially fills the interior space 230 such that the sensor
port 240 becomes covered by the fluid 258, the incompressible
nature of the fluid 258 will cause the pressure sensor 246, which
is in fluid communication with the interior space 230, to
experience a reduction in reduced pressure (a rise in absolute
pressure). A remaining void space 259 is shown.
[0036] In one illustrative embodiment, if the reduced-pressure
control unit 260 determines that, despite increased power or
passage of a wait time, the desired reduced pressure within
interior space 230 is below the desired reduced pressure level, the
reduced-pressure control unit 260 will send an alarm signal or send
a pump control signal to the current control unit 256 to shut down
vacuum pump 248. The reduced-pressure control unit 260 may shut
down or send an alarm if the reduced-pressure control unit 260 is
unable to increase the reduced pressure (lower the absolute
pressure) within interior space 230 due to a blockage in one of the
conduits 222, 236, 242. Additional examples how the
reduced-pressure control unit 260 may operate are provided in
connection with FIGS. 3 and 4.
[0037] Referring now primarily to FIG. 3, a schematic graph is
presented showing operational parameters that may be used by the
reduced-pressure control unit 260 in the reduced-pressure system
200 in FIGS. 2A-2C with respect to pressure and power. Power is
represented by the current in this illustrative embodiment. The
graph has an abscissa axis 302 and an ordinate axis 304. The
abscissa axis 302 shows a relative measurement of the power
provided to the vacuum pump 248 in the reduced-pressure system 200.
The ordinate axis 304 represents the pressure measured by the
pressure sensor 246 and that generally corresponds to the reduced
pressure delivered into the interior space 230 of the reservoir
224.
[0038] Referring to FIG. 2A and FIG. 3, just before the
reduced-pressure system 200 is activated, the reduced-pressure
system 200 may be represented on the graph of FIG. 3 at the first
point 306--no reduced pressure (gauge pressure) and no power. Once
activated, the vacuum pump 248 runs until the reduced pressure
exceeds the selected level A and is then turned off. The selected
level A may be pre-set or may be entered by a user or healthcare
provider. Thus, before the vacuum pump 248 is temporarily
deactivated, the reduced pressure may be represented at a second
point 308. The second point 308 shows that the reduced pressure has
now exceeded the threshold selected level A and shows that the
vacuum pump 248 is currently operating because of the positive
current measurement on the abscissa. At this time, the
reduced-pressure control unit 260 can tell the vacuum pump 248 to
shut down, such as by sending a pump control signal PC to the
current control unit 256. The vacuum pump 248 may remain off until
the pressure sensor 246 determines that the reduced pressure has
decreased below the threshold level A or some other set level. At
that time, the vacuum pump 248 will be reactivated to again restore
the pressure measured by the pressure sensor 244, which typically
corresponds with the pressure within interior space 230, to again
exceed level A.
[0039] In one illustrative embodiment, if the source conduit 236
begins to experience partial blocking, the previously used level of
reduced pressure supplied by vacuum pump 248 may not be able to
cause the reduced pressure in the interior space 230 (as measured
in the pressure sensor conduit 242 by the pressure sensor 244) to
exceed the threshold level A. Before concluding that the reservoir,
or canister, 224 is full and shutting down, the power level of the
vacuum pump 248 may first be increased by the reduced-pressure
control unit 260 for a time. The power level of the vacuum pump may
be increased all the way to a full power level or a selected level
as shown by reference line B on the graph. Thus, in one example the
reduced-pressure control unit 260 may determine that the pressure
at the pressure sensor 246 is below the pressure level A and that
the reduced pressure is not increasing. Then, full power or a
maximum power setting B may be applied to the vacuum pump 248 such
that the reduced-pressure system 200 may be represented on the
graph by a third point 310. If partial blockage is the main issue
that had otherwise kept the pressure from fully responding, the
vacuum pump 248 at the increased full power level may be able to
move to a fourth point 312, which is beyond pressure threshold
level A and the vacuum pump 248 will shut down until the pressure
decreases below level A again. If the blockage of the source
conduit 236 is such that even full power does not move the pressure
beyond level A after a given time, the alarm is signaled and the
vacuum pump 248 is shut down. Note that as shown in FIG. 2C, when
the incompressible fluid 258 covers the sensor port 240, the
increased power to the vacuum pump 248 will result in lowering the
pressure in the remaining void space 259 of reservoir 224, but will
not increase the reduced pressure and thus will not cause the
pressure measured by pressure sensor 246 to be beyond level A.
Accordingly, the system 200, and particularly the vacuum pump 248,
will shut down and give the full reservoir/blocked indication.
[0040] Referring now primarily to FIG. 4, an illustrative
embodiment of a reduced-pressure control unit 460 is presented. The
reduced-pressure control unit 460 includes a housing unit 462,
which contains various components for controlling a
reduced-pressure system, such as system 200 of FIG. 2A-2C. The
reduced-pressure control unit 460 may receive a number of different
input signals from input devices. The reduced-pressure control unit
460 is shown with a first input 464, which in this illustration is
a pressure signal P representative of the pressure within the
interior space of the reservoir as measured by a pressure sensor in
a pressure sensor conduit. If the pressure signal supplied to the
first input 464 is not already digitized, a first analog-to-digital
converter 466 may be included to receive and convert the pressure
signal to a digital signal. A second input 468 may be included. In
this illustration, the second input 468 is a supply signal, e.g., a
signal representative of the power data to the pump and in
particular may be a signal I. As before, if the supply signal I is
not already in a digitized form, a second analog-to-digital
converter 470 may be included to convert the signal to a digital
format.
[0041] Similarly, a third input signal 472 is shown and is merely
representative of other signals that may be provided to the
reduced-pressure control unit 460. For example, the third input
signal 472 may be a temperature signal that reflects the
temperature within the fluid in the reservoir. The fluid
temperature might affect the viscosity of the fluid and in turn
might influence such parameters as the interval time for waiting on
responses within the reduced-pressure system. If the representative
third input signal 472 is not already in a digitized form, another
analog-to-digital converter 474 may be included.
[0042] The signals received in the input signals 464, 468, 472,
(and converted if needed) may be delivered to a buffer memory 476
and either supplied to a memory unit 478 or directly delivered to a
microprocessor 482. It may be desirable to keep a recording of the
input data to allow different determinations, such as whether or
not the pressure is rising or decreasing. The memory unit 478 may
also be used to determine if no pressure change has been
experienced over an extended time period while the reduced-pressure
source has been off. In that case, it may be desirable for the
reduced-pressure control unit 460 to provide a warning light that
the reduced-pressure delivery conduit, e.g. reduced-pressure
delivery conduit 222 FIG. 2A, may be blocked.
[0043] The microprocessor 482 is operable to carry out a number of
different determinations as to when the vacuum pump should be
increased in power, shut down, or when an alarm signal or other
signals should be produced as will be explained in connection with
FIG. 5. The microprocessor 482 has a number of outputs. A first
output 484 is a pump control signal that may be delivered to
control the vacuum pump. For example, the pump control signal 484
may be delivered to the current control unit 256 in FIG. 2A to
adjust the power to the vacuum pump 248 or to turn the vacuum pump
248 off. In embodiments with other reduced pressure sources, a
control signal may be used to adjust the supply rate. The
microprocessor 482 may also provide a second output 486, which may
be an alarm signal. The alarm signal may activate an audible alarm,
e.g. speaker 142 in FIG. 1. A third output 488 is a representative
output signal that may control other features, such as providing a
status light on a display, e.g. light or indicator 132 or 136 in
FIG. 1. A power supply 490 supplies power to various components
within the reduced-pressure control unit 460 and may be a battery
or may be conditioned power from another source.
[0044] For control units that utilize a microprocessor, such as
reduced-pressure control unit 460 of FIG. 4, the microprocessor,
e.g., microprocessor 482, may be designed to be used in conjunction
with a memory device, e.g. buffer memory 476 or memory unit 478, to
conduct a number of different operations in using the input signals
464, 468, and developing of appropriate output signals, e.g.
signals 484, 486, 488.
[0045] Referring now primarily to FIG. 5, one illustrative
presentation of the possible logic or operation that may be used
with a control unit is presented. The operation begins at step 502
and proceeds to decision step 504 where a question is asked: is the
reduced pressure from a pressure sensor in a pressure sensor
conduit greater than threshold value? (The reduced pressure in the
pressure sensor conduit typically is the same as in the reservoir
to which the pressure sensor conduit is fluidly coupled). In other
words, is the absolute value of the negative gauge pressure greater
than the threshold value? With reference to FIG. 3, the question is
asking whether or not the pressure point is below the threshold
value line A. If the answer is in the affirmative, an increase in
the reduced pressure is not necessary, and the system can wait.
Accordingly, the flow proceeds to step 506 where the system waits
for a certain time interval before again returning to decision step
504. This time interval and the others may be pre-programmed or may
be entered by a healthcare provider or user.
[0046] If the response to decision step 504 is in the negative,
additional reduced pressure is desired and the vacuum pump is
activated at step 508. Then, the vacuum pump or reduced-pressure
source is allowed to act for a certain time interval at step 510
before the system goes to decision step 512 where the following
question is asked: is the reduced pressure increasing? In other
words, is the absolute value of the reduced pressure in the
reservoir increasing--taking on a larger number? If so, the system
proceeds to decision step 514, which again asks if the reduced
pressure is greater than a threshold value. If the answer is in the
affirmative, the system proceeds to step 516 and the pump or
reduced-pressure source is turned off. In that case, the system
would update the signal indicating no blockage/not full in step 518
and would return along path 520 to go back to decision step
504.
[0047] If the response to decision step 514 is in the negative, the
system may wait for a specified time interval at step 522 before
again returning to decision step 512. This forms a loop and the
loop can continue until the threshold value is reached or until the
reduced pressure is no longer increasing. Once the pressure is no
longer increasing, the answer at decision step 512 is in the
negative, and the system proceeds to decision step 524. Decision
step 524 asks whether or not the pump is at full power (or
reduced-pressure source at maximum reduced pressure). If the answer
is in the negative, the power to the pump is increased at step 526,
and if in the affirmative, a timer is started at step 528. Then,
decision step 530 is reached, and decision step 530 asks the
question: is the reduced pressure increasing? If the answer is in
the affirmative, the analysis continues along path 532 to decision
step 514. If the answer is in the negative, the process continues
to decision step 534. Decision step 534 asks if the timer started
at 528 has reached the maximum timer value. If the timer has not,
additional time is taken with step 536. If the timer has, the
process has timed out and the process proceeds to step 538 where a
signal indicating reservoir (canister) full/blockage is sent. In
addition, an alarm signal may be sent in step 540. The vacuum pump
or reduced-pressure source may then be turned off at step 542. The
process ends at step 544. It will be appreciated that the reservoir
(canister) full/blockage signal is given when either the reservoir
is deemed full or when a blockage exists. Either way, the system is
unable to restore the pressure in the reservoir and a
reservoir-full/blockage condition exists. This logic is only one of
the many ways that the control unit may be programmed.
[0048] Although the present invention and its advantages have been
disclosed in the context of certain illustrative, non-limiting
embodiments, it should be understood that various changes,
substitutions, permutations, and alterations can be made without
departing from the scope of the invention as defined by the
appended claims. It will be appreciated that any feature that is
described in a connection to any one embodiment may also be
applicable to any other embodiment.
* * * * *