AU2015200161A1 - Reduced-pressure treatment systems with reservoir control - Google Patents

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 (224) having an interior space (230) operable to contain the fluids. A reduced-pressure delivery conduit (222) is placed in fluid communication with the interior space (230) for delivering the reduced pressure to the desired site. A source conduit (236) and a pressure sensor conduit (246) are placed in fluid communication with the interior space (230). A pressure sensor (246) is placed in fluid communication with the pressure sensor conduit (242). A reduced-pressure source (248) is placed in fluid communication with the source conduit. A reduced- pressure control (260) unit is associated with the pressure sensor (254) and the reduced-pressure source (248) 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. Figure 2A D m Vt, w

Description

- 1 TITLE OF THE INVENTION REDUCED-PRESSURE TREATMENT SYSTEMS WITH RESERVOIR CONTROL CROSS REFERENCE TO RELATED APPLICATIONS 5 [0001] The present invention claims the benefit, under 35 U.S.C. § 119(e), of the filing of U.S. Provisional Patent Application serial number 61/087,377, entitled "A Reduced-Pressure Treatment System with Reservoir Control." filed August 8, 2008, which is incorporated herein by reference for all purposes. BACKGROUND 10 [00021] The present invention relates generally to medical treatment systems and devices, and in more particular embodiments, to reduced-pressure treatment systems with reservoir control. [0002a] Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of 15 common general knowledge in the field. [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. 20 [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 25 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.

-2 BRIEF SUMMARY 100051 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 5 illustrative embodiment, a reduced-pressure treatneit system tor treating a tissue site on a patient includes a manifld member for placing proxinate 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 .0 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 ,5 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-fullloekae condition exists, [0061 According to another illustrative embodiment, a reduced-pressure system for !0 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. 'lThe reduaced-pressure system further includes a pressure sensor in fluid communication with the 25 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 reducedpressure 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 30 condiion exists.

-3 [0007] According to another illustrative embodiment, areduced-pressure system includes a reservoir housing that forms an interior space and a reduced-pres sure 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 5 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 0 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 reducedpressure 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 s ource to provide a desired pressure to the reservoir and to shutdown when 5 the reservoir is fu1ll1 {0008] According to another illustrative embodiment, a method of detecting a ll 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, colecting fluid from the tissue 0 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 25 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 30 deli very site. The method of manufacturing further includes fluidly coupling a source conduit to the interior space, flidly 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 -4 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 5 full/blockage condition exists. [0009a] According to a first aspect of the present invention there is provided a reduced-pressure treatment system for treating a tissue site on a patient, the system comprising: a manifold member for placing proximate the tissue site; 10 an over-drape for providing a fluid seal over the manifold member and the patient; a reduced-pressure subsystem for delivering reduced pressure to the over-drape; and wherein the reduced-pressure subsystem comprises: a reservoir having an interior space operable to contain fluids, a reduced-pressure delivery conduit in fluid communication with the 15 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, a pressure sensor in fluid communication with the pressure sensor conduit, a reduced-pressure source in fluid communication with the source conduit 20 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 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. 25 [0009b] According to a second aspect of the present invention there is provided a reduced-pressure system for providing reduced pressure and for receiving fluids, the reduced-pressure system comprising: a reservoir having an interior space operable to contain the fluids; a reduced-pressure delivery conduit in fluid communication with the interior space 30 for delivering reduced pressure; a source conduit in fluid communication with the interior space; -5 a pressure sensor conduit in fluid communication with the interior space and separate from the source conduit; a pressure sensor in fluid communication with the pressure sensor conduit; a reduced-pressure source in fluid communication with the source conduit and 5 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 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. 10 [0009c] According to a third aspect of the present invention there is provided a reduced-pressure system for supplying reduced pressure for a medical application and receiving a fluid, the system comprising: a reservoir housing that forms an interior space; a reduced-pressure source for delivering reduced pressure, the reduced-pressure 15 source fluidly coupled to the interior space of the reservoir and operable to deliver a reduced pressure to the interior space, wherein the reduced-pressure source is responsive to a control signal; a supply conduit fluidly coupled to the interior space; a supply sensor for measuring a supply rate of reduced pressure delivered by the 20 reduced-pressure source and operable to develop a signal I indicative of reduced pressure made available to the supply conduit; a pressure sensor conduit fluidly coupled to the interior space; a pressure sensor in fluid communication with the pressure sensor conduit, the pressure sensor operable to develop a signal P indicative of a pressure level in the pressure 25 sensor conduit proximate the pressure sensor; and a reduced-pressure control unit coupled to the supply sensor, pressure sensor, and the reduced-pressure source, the reduced-pressure control unit 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-pressures source to provide a desired pressure to the reservoir and to 30 shutdown when the reservoir is full.

-6 [0009d] According to a fourth aspect of the present invention there is provided a method of detecting a fill status of a reservoir for use in treating a patient with a reduced pressure treatment system, the method comprising the steps of: generating a reduced pressure in fluid communication with the reduced-pressure 5 treatment system; applying the reduced pressure to a tissue site; collecting fluid from the tissue site in the reservoir; monitoring a pressure within the reservoir; wherein the reservoir has a pressure sensor conduit in fluid communication with the 10 reservoir and a supply conduit in fluid communication with the reservoir, and wherein step of monitoring the pressure within the reservoir comprises monitoring pressure within the pressure sensor conduit; and terminating the application of reduced pressure when the pressure in the pressure sensor conduit decreases below a selected absolute value for specified time interval. 15 [0009e] According to a fifth aspect of the present invention there is provided a method of manufacturing a reduced-pressure system, the method comprising: forming a reservoir having an interior space operable to contain fluids; fluidly coupling a reduced-pressure delivery conduit to the interior space, the reduced- pressure delivery conduit for delivering a reduced pressure to a delivery site; 20 fluidly coupling a source conduit to the interior space, the source conduit for delivering reduced pressure to the interior space; fluidly coupling a pressure sensor conduit to the interior space; fluidly coupling a pressure sensor to the pressure sensor conduit; providing a reduced-pressure source responsive to a control signal; 25 coupling the reduced-pressure source to the source conduit; providing a reduced-pressure control unit 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; and associating the reduced-pressure control unit with the pressure sensor and reduced 30 pressure source.

-7 [0009f] According to another aspect of the present invention there is provided a reduced-pressure treatment system for treating a tissue site on a patient, the system comprising: a manifold member for placing proximate the tissue site; 5 an over-drape for providing a fluid seal over the manifold member and the patient; a reduced-pressure subsystem for delivering reduced pressure to the over-drape; and wherein the reduced-pressure subsystem comprises: a reservoir having an interior space operable to contain fluids, a reduced-pressure delivery conduit in fluid communication with the interior 10 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, a pressure sensor in fluid communication with the pressure sensor conduit, a reduced-pressure source in fluid communication with the source conduit and 15 operable to deliver reduced pressure to the source conduit, a power line coupled to the reduced-pressure source, a power sensor coupled to the power line, the power sensor adapted to measure a supply data signal correlated to a supply rate of reduced pressure, and a reduced-pressure control unit associated with the pressure sensor, the power 20 sensor, and reduced-pressure source, the reduced-pressure control unit operable to: receive a pressure data signal from the pressure sensor, receive the supply data signal from the power sensor, determine when a partial blockage condition, reservoir-full condition, or blockage condition exists based on the pressure data signal and the supply data 25 signal, increase the rate of delivery of reduced pressure if a partial blockage condition exists, and turn off the reduced-pressure source if a reservoir-full or blockage condition exists. 30 [0009g] According to another aspect of the present invention there is provided a reduced-pressure system for providing reduced pressure and for receiving fluids, the reduced-pressure system comprising: -8 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 adapted to be in 5 fluid communication with a regulated wall suction unit; a pressure sensor conduit in fluid communication with the interior space and separate from the source conduit; a pressure sensor in fluid communication with the pressure sensor conduit; a supply sensor adapted to measure a supply data signal indicative of a valve opening 10 on the regulated wall suction unit; and a reduced-pressure control unit associated with the pressure sensor and the supply sensor; wherein the reduced-pressure control unit is operable to receive a pressure data signal from the pressure sensor, receive the supply data signal from the supply sensor, and to 15 determine when a reservoir-full condition or a blockage condition exists based on the pressure data signal and the supply data signal. [0009h] According to another aspect of the present invention there is provided a reduced-pressure system for supplying reduced pressure for a medical application and receiving a fluid, the system comprising: 20 a reservoir housing that forms an interior space; a reduced-pressure source for delivering reduced pressure, the reduced-pressure source fluidly coupled to the interior space of the reservoir and operable to deliver a reduced pressure to the interior space, wherein the reduced-pressure source is responsive to a control signal; 25 a source conduit fluidly coupled to the interior space; a power line coupled to the reduced-pressure source; a supply sensor coupled to the power line, the supply sensor operable to develop a signal I indicative of reduced pressure supplied to the source conduit; a pressure sensor conduit fluidly coupled to the interior space; 30 a pressure sensor in fluid communication with the pressure sensor conduit, the pressure sensor operable to develop a signal P indicative of a pressure level in the pressure sensor conduit proximate the pressure sensor; and -9 a reduced-pressure control unit coupled to the supply sensor, pressure sensor, and the reduced-pressure source, the reduced-pressure control unit 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 5 shutdown when the reservoir is full. [0009i] According to another aspect of the present invention there is provided a method of manufacturing a reduced-pressure system, the method comprising: forming a reservoir having an interior space operable to contain fluids; fluidly coupling a reduced-pressure delivery conduit to the interior space, the 10 reduced-pressure delivery conduit for delivering a reduced pressure to a delivery site; fluidly coupling a source conduit to the interior space, the source conduit for delivering reduced pressure to the interior space; fluidly coupling a pressure sensor conduit to the interior space; fluidly coupling a pressure sensor to the pressure sensor conduit; 15 providing a reduced-pressure source responsive to a control signal; coupling the reduced-pressure source to the source conduit; coupling a power line to the reduced-pressure source; coupling a power sensor to the power line, the power sensor adapted to measure a supply data correlated to a supply rate of reduced pressure from the reduced-pressure source; 20 providing a reduced-pressure control unit operable to receive pressure data from the pressure sensor and supply data from the power sensor, and to determine when a reservoir full condition or a blockage condition exists based on the pressure data and the supply data; and associating the reduced-pressure control unit with the pressure sensor and reduced 25 pressure source. [0009j] According to yet another aspect of the present invention, there is provided a method of controlling a reduced-pressure treatment system, the method comprising: coupling a pressure sensor to a reservoir; coupling a supply sensor to a reduced-pressure source; 30 receiving a pressure signal from the pressure sensor, wherein the pressure signal is correlated to reduced pressure in the reservoir; - 10 receiving a supply signal from the supply sensor, wherein the supply signal is correlated to a supply rate of reduced pressure to the reservoir; and generating a control signal for the reduced-pressure treatment system based on the pressure signal and the supply signal; 5 wherein the control signal increases the supply rate if a blockage condition exists and terminates a supply of reduced pressure if the pressure signal does not rise in absolute value with an increased supply signal. [0009k] According to yet another aspect of the present invention, there is provided a method of controlling a reduced-pressure treatment system, the method comprising: 10 coupling a pressure sensor to a reservoir; coupling a supply sensor to a reduced-pressure source; receiving a pressure signal from the pressure sensor correlated to reduced pressure in the reservoir; receiving a supply signal from the supply sensor correlated to a supply rate of 15 reduced pressure to the reservoir; and generating a control signal for the reduced-pressure treatment system based on the pressure signal and the supply signal; wherein generating the control signal comprises identifying a blockage condition if the reduced-pressure source is not able to increase the reduced pressure within the reservoir 20 above a threshold for a predetermined time by increasing the supply rate of reduced pressure. [00091] According to yet another aspect of the present invention, there is provided a reduced pressure control unit having a microprocessor configured to: monitor a pressure signal correlated to reduced pressure within a reservoir; receive a supply signal correlated to a supply rate of reduced pressure to the 25 reservoir; and generate a control signal based on the pressure signal and the supply signal; wherein the control signal increases the supply rate if a blockage condition exists and terminates a supply of reduced pressure if the pressure signal does not rise in absolute value with an increased supply signal. 30 [0009m] According to yet another aspect of the present invention, there is provided a method of controlling a reduced-pressure treatment system, the method comprising: monitoring a pressure signal correlated to reduced pressure within a reservoir; - 11 receiving a supply signal correlated to a supply rate of reduced pressure; determining if the pressure signal decreases below a selected absolute value for a specified time interval; and terminating a supply of reduced pressure if the pressure signal does not rise in 5 absolute value with an increased supply signal. [0009n] According to yet another aspect of the present invention, there is provided a reduced-pressure control unit adapted for coupling with a pressure sensor, a supply sensor, and reduced-pressure source, the reduced-pressure control unit operable to receive pressure data from the pressure sensor and supply data from the supply sensor, to determine when a 10 reservoir-full or blockage condition exists, and to turn off the reduced-pressure source when a reservoir-full or blockage condition exists. [0009o] It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative. [0009p] Unless the context clearly requires otherwise, throughout the description and 15 the claims, the words "comprise", "comprising", and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to". [0010] Other features and advantages of the illustrative embodiments will become apparent with reference to the drawings and detailed description that follow. 20 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] FIGURE 1 is a schematic, perspective view of an illustrative embodiment of a 25 reduced-pressure treatment system with reservoir control with a portion shown in cross section; [0013] FIGURE 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] FIGURE 2B and 2C are schematic, elevational, cross-sectional views of a 30 portion of the reduced-pressure system of FIG. 2A; - 12 [0015] FIGURE 3 is a representative graph presenting illustrative operational parameters of a reduced-pressure treatment system according to one illustrative embodiment; [0016] FIGURE 4 is a schematic diagram of an illustrative embodiment of a reduced pressure control unit; and 5 [0017] FIGURE 5 is an illustrative flow chart of one possible approach to the logic incorporated into a reduced-pressure control unit in one illustrative embodiment. - - - 13 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [00181 In the flowing detailed description of the preferred embodiments, reference is made to the accompanying drawings that tbrm a part hereof, and in which is shown by way of lhustration specific preferred embodiments in which the invention may be practiced. These 5 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 0 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 100191 Referring to FIGURE 1; an illustrative embodiment of a reduced-pressure treatment system 100 for treating a tissue site 106, eg;. a wound 104, The tissue site 106 may be the bodily tissue of any human, animal, or other organism, including bone tissue, adipose .5 tissue, nusele tissue, dermal tissue, vascular tissue, connective tissue, cartilage, tendons, ligarents,or any other tissueUnless otherwise indicated, as used herein "of" 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, !0 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 25 system 100 may be built for relatively less money than conventional systems, achieve greater mechanical reliability, and operate in multiple orientations without false alarms. [00201 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 30 pressure, One such foam material that has been used is the VACa GranufoamDressing available from Kinetic Concepts inc. (KCI) of San Antonio, Texas. Any material or combination of materials may be used for the manifold material provided that the manifold -14 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 flids 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 5 area of tissue around the manifold. The plurality of flow pathways may be interconnected. Examples of mnmifolds may include, without limitation, devices that have structural elements arranged to form flow channels,cllular foansuch 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 0 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. Granufbam* 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 Granuibam@ ,5 material may be desirable in soni 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@ material or a Foamex technical foam (wwwJameN.com) In some instances it may be desirable to add ionic silver to the ftam in a microbonding process or to add other substances to the manifold member such as 10 antimicrobial agents. The manifold member 114 could be a bio-absorbable or bo-inert material or an anisotropic material. [0221 The sealing subsystem 116 includes an over-drape 118, or drape. The over-drape 118 cover's 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 25 patients 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; hydrogen; or other sealing device. If a tape is used, the tape may be formed of the same material as the over-drape I18 with a pre-applied, pressure-sensitive adhesive, The pressure-sensitive adhesive 124 may 30 be applied on a second, patient-facing side of drape extension 120. The pressuresensitive adhesive 124 provides a substantially flid seal between the over-drape 118 and the epidermis 108 of the patient. "Fluid seal.,," or mseal. ineans a seal adequate to hold reduced pressure at a - 15 desired site given the particular reduced-pressure subsystem involved- Before the over-drape 118 is secured to the patient, the pressuresensitive adhesive 124 may have removable strips covering the adhesive 124 10023} The over-drape 118 may be an elastomeric material that provides a fluid seal. 5 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 mbber-like properties. More specifically, most elastoniers 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 defonnation., Examples of .0 elastomers may include, but are not I mited tonatural mbbers, polyisoprene. styrene butadiene rubber, chloroprene rubberpolybutadiene, nitrile rubber, butyl rubber, ethylene propylene rubber, ethylene propylene diene monome, chlorosulfonated polyethylene, polysulfide rubber, polyurethaneEVA flm, co-polyester and silicones. Specific examples of sealing member materials include a silicone drape, 3M Tegaderrn@ drape. acrylic drape such as one available .5 from Avery Dennison, or an incise drape, [00241 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 vacun pumps wall suction, !0 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 ig [00251 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 25 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 pressme 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 30 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 terns "vacuum" -16 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 5 10026] In the illustrative embodiment of FIGURE 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. 0 [00271 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 .5 reduced-pressure subsystem 126 includes a reduced-pressure control unit analogous to a reduced-pressure control unit 260 in FIGURE 2A. [00281 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. hi one illustrative embodiment, the port 146 is a TRAC* technology 10 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 25 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 30 106 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 - 17 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 5 breaks in the treatment, the status of the reservoir 150 may be visualy 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 ful 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 fidl or blocked. [00,0] Referring now primarily to IOURE 2A, an illustrative embodiment of a reduced-pressure system 200which nay be used as the reduced-pressure subsystem 126 of the reduced-pressure treatment system 100 in FIGURE 1 is presented. The reduced pressure is provided by the reduced pressure system 200 and ultimately delivered by a reducedpressue delivery conduit 222 for medical purposes to a delivery site, e g,, reduced pressure interface 144 5 and tissue site 106 of FIGURE 1T hMe 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 !0 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 fuid 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 25 communicationor 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 conmunication, or fluidly coupled, wth the interior space 230s While the sensor port 240 is shown slightly below the source port 234, it should he noted that these ports 234, 240 may be on the same vertical level in other embodiments, 30 [00311 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 -18 242. For example, the source conduit 236 is shown with a first filter unit 238, and tihe pressure sensor conduit 242 is shown with a second filter unit 244, While tilter units 238 and 244 are shown as single -units, it is Io be understood that a plurality of filters may make up each filter unit 5 10032] 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 0 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 {9033] 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 5 vacuum pump 248 works to generate the reduced pressure that is introduced into the source conduit 23.6 In the illustrative embodiment, the vacuum punmp 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 !0 254 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 .L 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, 25 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 conunnication conduit 255 to the reduced-pressure control unit 260. 30 100341 The reduced-pressure control unit 260 contains circuitry or a microprocessor that controls functons 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.

-19 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 fill 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 5 reduced-pressure control unit 260 may send an alarm to a speaker 216 as well as providing an alam1 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 comrmunication 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 0 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 in put 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. 5 [00351 Referring now primarily to FIGURES 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. FIGURE 2A shows this initial state with the reservoir 224 empty. As the reduced pressure is delivered for !0 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. FIGURE 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 25 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 poit 240 becomes covered by the fluid 258, the incompressible nature of the fluid 258 will cause the pressure sensor 246, which is in fluid 30 conununication with the interior space 230, to experience a reduction in reduced pressure (a rise in absolute pressure), A remaining void space 259 is shown.

-20 [00361 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 ahm signal or send a pump control signal to the current control 5 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 FIGURES 3 and 4. [100371 Referring now primarily to FIGURE 3, a schematic graphics presented showing operational parameters that may be used by the red ucedpressure control unit 260 in the reduced-pressure system 200 in FIGURES 2A-20with 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 [0038J Referring to FIGURE 2A and FIURE 3, just before the reduced-pressure system 200 is activated, the reduced-pressure system 200 may be represented on the graph of !0 FIGURE 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 mnay be pre-set or may he 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 25 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 30 decreased below the threshold level A or some other set level. At that time, the vacuum pump 248 will be reactivated to agaln restore the pressure measured by the pressure sensor 244, which typically corresponds with the pressure within interior space 230, to again exceed level A.

-21 100391 In one illustrative embodinent, 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 5 concluding that the reservoir, or canister,224 is hil and shutting down, the power level of the vacuum punp 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 relrence 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 0 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 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 pIump 248 at the increased full power level may be able to move to a fourth point 312, which is .5 beyond pressure threshold level A and the vacuumn pump 248 will shut down until the pressure decreases below lvel 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 signed and the vacun punp 248 is shut down Note that as shown in FIGURE 2C, when the incompressible flid 258 covers the sensor port 240, the increased power to the vacuum pump 0 248 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 fidl reservoir/blocked indication, 100401 Referring now primarily to FIGURE 4, an illustrative embodiment of a reduced 25 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 FIGURE 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,vwich in this illustration is a pressure signal P representative of the 30 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 frst input 464 is not already digitized,a first analog-to-digital converter 466 may be included to receive and convert the pressure signal - 22 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 L 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. 5 [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 10 pressure system, If the representative third input signal 472 is not already in a digitized forrn, 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 15 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 FIGURE 2A, 20 may be blocked. 100431 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 FIGURE 5, The microprocessor 482 has a number of outputs. A first output 484 is a pump 25 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 FIGURE 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 30 alarm signal may activate an audible alarm, e.g, speaker 142 in FIGURE 1, A third output 488 is a representative output signal that may control other features, such as providing a status light on a display, eg. light or indicator 132 or 136 in FIGURE 1. A power supply 490 supplies - 23 power to various components within the reduced-pressure control unit 460 and may be a battery or may be conditioned power from another source. 100441 For control units that utilize a microprocessor, such as reduced-pressure control unit 460 of FIGURE 4, the niicroprocessor, e.g., microprocessor 482, may be designed to be 5 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. eg signals 484, 486,488. [00451 Refering now primarily to FGURE 5, one illustrative presentation of the possible logic or operation that may be used with a control unit is presented The operation -0 begins at step 502 and proceeds to decision step 504 where a question is asked: is the reduced pressure front 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 FIGURE 3 the 5 question is asking whether or not the pressure point is below the threshold value line A, If the answer is in the affrnative, 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-progranmned or may be entered by a healatchca provider or user. !0 100461 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 tor a certain time interval at step 510 before the system goes to decision step 512 where die following question is asked: is the reduced pressure increasing? In other words is the absolute value of the reduced pressure in the reservoir 25 increasing-taking on a larger number? If soothe system proceeds to decision step 514, which again asks if the reduced pressure is greater than a threshold value, If die answer is in the affirmative, the system proceeds to step 516 and the pump or reduced-pressure source is turned oft 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 30 100471 If the response to decision step 514 is in the negative, the system may wait for a speciied 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 - 24 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 fal1 power (or reduced-pressure source at maximun reduced pressure). If the answer is in the negative the power to the pump is increased at step 526, and if 5 in the affinnatixve, a timer is started at step 528. Then, decision step 530 is reached, and decision step 530 asks the question li 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 0 step 536 If the timer has, the process has timed out and the process proceeds to step 538 where a signal indicating reservoir (canister) fidlblockage is sent In addition, an alam signal may be sent in step 540. The vacuum pump or reduced-pressure source may then he turned off at step 542. The process ends at step 544, It will be appreciated that the reservoir (canister) ful/blockage signal is given when either the reservoir is deemed full or when a blockage exists 5 Either way, the system is unable to restore the pressure in the reservoir and a reservoir f41blockage condition exists' This logic is only one of the many ways that the control unit may be progranmmed. f0048] Although the present invention and its advantages have been disclosed in the context of certain illustrative, non-limiting embodiment it should be understood that various - changes, substitutions, operations, and alterations can he 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,

Claims (25)

1. A method of controlling a reduced-pressure treatment system, the method comprising: coupling a pressure sensor to a reservoir; coupling a supply sensor to a reduced-pressure source; receiving a pressure signal from the pressure sensor, wherein the pressure signal is correlated to reduced pressure in the reservoir; receiving a supply signal from the supply sensor, wherein the supply signal is correlated to a supply rate of reduced pressure to the reservoir; and generating a control signal for the reduced-pressure treatment system based on the pressure signal and the supply signal; wherein the control signal increases the supply rate if a blockage condition exists and terminates a supply of reduced pressure if the pressure signal does not rise in absolute value with an increased supply signal.

2. The method of claim 1, wherein generating a control signal comprises determining if a blockage condition exists based on the pressure signal and the supply signal.

3. The method of claim 1 or claim 2, wherein the supply signal is correlated to power supplied to the reduced pressure source.

4. The method of claim 1 or claim 2, wherein the supply signal is correlated to current supplied to the reduced pressure source.

5. The method of claim 1 or claim 2, wherein the supply signal is indicative of a valve opening on the reduced-pressure source.

6. The method of any one of the preceding claims, further comprising generating an alarm signal if a blockage condition exists and the pressure signal does not rise in absolute value with the increased supply signal.

7. The method of any one of the preceding claims, wherein generating the control signal comprises: determining if a reservoir-full condition exists based on the pressure signal and the supply signal; and - 26 turning off the reduced-pressure source if the reservoir-full condition exists.

8. The method of any one of the preceding claims 1 to 6, wherein generating the control signal comprises providing a desired pressure to the reservoir and turning off the reduced pressure source if the reservoir is full.

9. A method of controlling a reduced-pressure treatment system, the method comprising: coupling a pressure sensor to a reservoir; coupling a supply sensor to a reduced-pressure source; receiving a pressure signal from the pressure sensor correlated to reduced pressure in the reservoir; receiving a supply signal from the supply sensor correlated to a supply rate of reduced pressure to the reservoir; and generating a control signal for the reduced-pressure treatment system based on the pressure signal and the supply signal; wherein generating the control signal comprises identifying a blockage condition if the reduced-pressure source is not able to increase the reduced pressure within the reservoir above a threshold for a predetermined time by increasing the supply rate of reduced pressure.

10. The method of claim 9, wherein the control signal increases the supply rate if a blockage condition exists.

11. The method of claim 9 or claim 10, wherein the blockage condition is a partial blockage condition.

12. The method of claim 9 or claim 10, wherein the blockage condition is a full canister condition.

13. The method of any one of the preceding claims 9 to 12, wherein the supply signal is correlated to power supplied to the reduced pressure source.

14. The method of any one of the preceding claims 9 to 12, wherein the supply signal is correlated to current supplied to the reduced pressure source. - 27

15. The method of any one of the preceding claims 9 to 12, wherein the supply signal is indicative of a valve opening on the reduced-pressure source.

16. The method of any one of the preceding claims 9 to 15, further comprising generating an alarm signal if a blockage condition exists.

17. The method of any one of the preceding claims 9 to 16, wherein the control signal comprises: a signal to shut down the reduced-pressure source.

18. A reduced-pressure control unit having a microprocessor configured to: monitor a pressure signal correlated to reduced pressure within a reservoir; receive a supply signal correlated to a supply rate of reduced pressure to the reservoir; and generate a control signal based on the pressure signal and the supply signal; wherein the control signal increases the supply rate if a blockage condition exists and terminates a supply of reduced pressure if the pressure signal does not rise in absolute value with an increased supply signal.

19. The reduced-pressure control unit of claim 18, wherein generating the control signal comprises determining if the blockage condition exists based on the pressure signal and the supply signal.

20. The reduced-pressure control unit of claim 18 or claim 19, wherein the microprocessor is further configured to generate an alarm signal if a blockage condition exists and the pressure signal does not rise in absolute value with the increased supply signal.

21. The reduced-pressure control unit of any one of the preceding claims 18to20, wherein determining if the blockage condition exists comprises determining if the pressure signal decreases below a selected absolute value for a specified time interval and the pressure signal does not rise in absolute value with an increased supply signal.

22. The reduced-pressure control unit of claim 18, wherein generating the control signal comprises providing a desired pressure to the reservoir and turning off the reduced pressure if the reservoir is full. - 28

23. A method of controlling a reduced-pressure treatment system, the method comprising: monitoring a pressure signal correlated to reduced pressure within a reservoir; receiving a supply signal correlated to a supply rate of reduced pressure; determining if the pressure signal decreases below a selected absolute value for a specified time interval; and terminating a supply of reduced pressure if the pressure signal does not rise in absolute value with an increased supply signal.

24. The method of claim 23, wherein the reduced pressure is supplied with a vacuum pump.

25. A reduced-pressure control unit adapted for coupling with a pressure sensor, a supply sensor, and reduced-pressure source, the reduced-pressure control unit operable to receive pressure data from the pressure sensor and supply data from the supply sensor, to determine when a reservoir-full or blockage condition exists, and to turn off the reduced-pressure source when a reservoir-full or blockage condition exists.