HK1135053B - System and method for managing reduced pressure at a tissue site - Google Patents

Abstract

The illustrative embodiments described herein are directed to an apparatus and method for managing reduced pressure at a tissue site. The apparatus includes a reduced pressure source that generates reduced pressure. The reduced pressure is delivered to the tissue site via a delivery tube. The apparatus includes a single pressure sensor. The single pressure sensor detects an actual reduced pressure at the tissue site. The apparatus also includes a controller. The controller determines a responsiveness of the actual reduced pressure measured by the single pressure sensor to an increase in reduced pressure generated by the reduced pressure source. The apparatus includes an indicator. The indicator emits a signal when the controller determines that the actual reduced pressure measured by the single pressure sensor is nonresponsive to the increase in reduced pressure generated by the reduced pressure source.

Description

Systems and methods for managing reduced pressure at a tissue site

Technical Field

The present invention relates generally to the field of tissue treatment, and more particularly to systems and methods for applying reduced pressure at a tissue site.

Background

Clinical studies and practice have shown that providing reduced pressure in the vicinity of a tissue site can increase and accelerate the growth of new tissue at the tissue site. The use of this phenomenon is numerous, but the use of reduced pressure in the treatment of wounds has been particularly successful. The use of reduced pressure to treat wounds is sometimes referred to in the medical community as "negative pressure tissue treatment," reduced pressure therapy, "or" vacuum therapy. This type of treatment provides a variety of benefits, including faster healing and increased formation of granulation tissue.

It may be desirable to properly manage the reduced pressure at the tissue site caused by the reduced pressure treatment system to maintain or increase the effectiveness of the reduced pressure treatment. In addition, leaks and blockages in components of the reduced pressure treatment system may need to be detected and corrected to maintain effective treatment. For example, a leak or blockage in a tube connecting a reduced pressure source, such as a vacuum pump, to a tissue site may interrupt the reduced pressure treatment being performed at the tissue site. Management or control of reduced pressure treatment systems may be generally referred to as "pump pressure control" or "differential pressure control".

In one currently used pump pressure control system, pressure is measured at the pump outlet and delivered to the control system, which drives the pump to reach a target pressure at the pump outlet. However, because the pressure is not measured at or near the tissue site, the system ignores any difference between the pressure measured at the pump outlet and the pressure near the tissue site. Thus, this currently used pump pressure control system does not provide information about leaks or blockages occurring between the tissue site and the pump.

Currently used differential pressure control systems apply two sensors to measure the pressure at the pump outlet and the tissue site. The pressures measured by the two sensors are compared so that leaks or blockages occurring in the reduced pressure treatment system can be identified. However, current differential pressure control systems use two sensors that increase the size, weight, cost, and complexity of the system. For example, the use of two sensors increases the amount of electronic circuitry and power sources used by the reduced pressure treatment system. Additionally, comparing the measurements of two different sensors requires that the reduced pressure treatment system include circuitry and software to compare. The additional components required by current differential pressure control systems reduce the ability of those systems to treat low severity wounds and wounds of ambulatory patients. In addition, the additional components increase the mandatory (optional) and weight of the reduced pressure treatment system, thereby increasing patient discomfort and limiting patient mobility.

Disclosure of Invention

To reduce the problems with reduced pressure treatment systems, the illustrative embodiments described herein relate to an apparatus and method for managing reduced pressure at a tissue site. The device includes a reduced-pressure source that generates a reduced pressure. Reduced pressure is delivered to the tissue site via a delivery tube. The device includes a single pressure sensor. The separate pressure sensor is connected to the control tube and is operable to detect an actual reduced pressure at the tissue site. The apparatus also includes a controller. The controller is coupled to the separate pressure sensor and the reduced pressure source, the controller being configured to detect a change in an operating parameter of the reduced pressure source, the change in the operating parameter of the reduced pressure source being indicative of a change in the reduced pressure generated by the reduced pressure source, the controller being further configured to determine a responsiveness (responsiveness) of the actual reduced pressure measured by the separate pressure sensor to an increase in the reduced pressure generated by the reduced pressure source. The device includes an indicator. The indicator emits a signal when the controller determines that the actual reduced pressure measured by the separate pressure sensor is unresponsive to an increase in reduced pressure generated by the reduced pressure source. And wherein the unresponsive condition is determined by at least one of: (1) monitoring whether the actual reduced pressure at the tissue site increases over a predetermined period of time, and (2) monitoring whether the actual reduced pressure at the tissue site reaches a target reduced pressure over the predetermined period of time.

The reduced pressure source may generate a reduced pressure when the actual reduced pressure at the tissue site, as detected by the separate pressure sensor, exceeds the target reduced pressure.

The means for managing reduced pressure at the tissue site may also include a pressure relief valve connected to the delivery tube that opens to reduce the actual reduced pressure at the tissue site when the actual reduced pressure at the tissue site detected by the individual pressure sensor exceeds the target reduced pressure by a predetermined threshold.

The reduced-pressure source may generate an increased reduced pressure when the target reduced pressure exceeds the actual reduced pressure at the tissue site detected by the individual pressure sensors.

The apparatus for managing reduced pressure at a tissue site may further comprise: a control tube, wherein a separate pressure sensor detects an actual reduced pressure at the tissue site via the control tube; and a control tube relief valve connected to the control tube, the control tube relief valve relieving a pressure reduction in the control tube when a blockage in the control tube is detected.

The apparatus for managing reduced pressure at a tissue site may further comprise: a manifold, wherein a separate pressure sensor detects actual reduced pressure at the tissue site through the manifold via the control tube.

The control tube may be a first lumen, the delivery tube may be a second lumen, and the first and second lumens may be in separate multi-lumen tubes.

The indicator may be a light emitting diode and the signal may be the illumination of the light emitting diode.

The device may not include other pressure sensors than the single pressure sensor.

The reduced-pressure source may include a motor having a speed.

The sensor may detect a speed of the motor, and wherein the indicator emits a signal when the speed of the motor changes by a threshold amount.

The illustrative embodiments also provide a method for managing reduced pressure at a tissue site. The method determines a target reduced pressure. The method detects an actual reduced pressure at the tissue site using a separate pressure sensor. The process compares the actual reduced pressure with the target reduced pressure to form a comparison of the pressure data. The method performs a reduced pressure management function based on the comparison.

The step of performing a reduced pressure management function based on the comparison may include: the reduced pressure generated by the reduced-pressure source is reduced in response to the actual reduced pressure exceeding the target reduced pressure.

The method for managing reduced pressure at a tissue site may further comprise: a relief valve that reduces the actual reduced pressure at the tissue site is opened in response to the actual reduced pressure exceeding the target reduced pressure by a predetermined threshold.

The method for managing reduced pressure at a tissue site may further comprise: the generated reduced pressure is eliminated by turning off the reduced-pressure source in response to the actual reduced pressure exceeding the target reduced pressure by a predetermined threshold.

The step of performing a reduced pressure management function based on the comparison may include: the reduced pressure generated by the reduced-pressure source is increased in response to the target reduced pressure exceeding the actual reduced pressure.

The method for managing reduced pressure at a tissue site may further comprise: the indicator is used to emit a signal when the actual reduced pressure at the tissue site is unresponsive to increasing the reduced pressure generated by the reduced pressure source.

When the actual reduced pressure at the tissue site fails to increase within the predetermined period of time in response to increasing the reduced pressure generated by the reduced pressure source, the actual reduced pressure at the tissue site may be unresponsive to increasing the reduced pressure generated by the reduced pressure source.

The actual reduced pressure at the tissue site may be unresponsive to increasing the reduced pressure generated by the reduced pressure source when the actual reduced pressure at the tissue site fails to reach the target reduced pressure within the predetermined period of time in response to increasing the reduced pressure generated by the reduced pressure source.

The predetermined period of time may be in the range of 4 seconds to 6 seconds.

In another embodiment, the method uses a reduced pressure source to increase the generated reduced pressure. The method determines an actual reduced pressure at the tissue site using a separate pressure sensor. The method emits a signal using an indicator in response to an actual reduced pressure at the tissue site being unresponsive to increasing the generated reduced pressure.

Also provided is a method for managing reduced pressure at a tissue site, the method comprising: detecting, using a controller, a change in an operating parameter of a reduced-pressure source, the change in the operating parameter of the reduced-pressure source being indicative of a change in reduced pressure generated by the reduced-pressure source; determining an actual reduced pressure at the tissue site using a separate pressure sensor; emitting a signal using an indicator when actual reduced pressure at the tissue site is unresponsive to increasing the reduced pressure; and wherein the unresponsive condition is determined by at least one of: (1) monitoring whether the actual reduced pressure at the tissue site increases over a predetermined period of time, and (2) monitoring whether the actual reduced pressure at the tissue site reaches a target reduced pressure over the predetermined period of time. The method for managing reduced pressure at a tissue site may further comprise: determining a target reduced pressure for the tissue site; and comparing the actual reduced pressure detected by the individual pressure sensors to the target reduced pressure. The method for managing reduced pressure at a tissue site may further comprise: the reduced pressure generated by the reduced-pressure source is reduced in response to the actual reduced pressure exceeding the target reduced pressure.

Drawings

FIG. 1 is a block diagram of an apparatus for managing reduced pressure at a tissue site according to an illustrative embodiment of the invention;

FIG. 2 is a perspective view of a multi-lumen tube (multi-lumen tube) according to an illustrative embodiment of the invention;

FIG. 3 is a perspective view of a multi-lumen tube according to an illustrative embodiment of the invention;

FIG. 4 is a flowchart illustrating a method for managing reduced pressure at a tissue site in accordance with an illustrative embodiment of the present invention;

FIG. 5 is a flowchart illustrating a method for managing reduced pressure at a tissue site in accordance with an illustrative embodiment of the present invention;

FIG. 6 is a flowchart illustrating a method for managing reduced pressure at a tissue site in accordance with an illustrative embodiment of the invention; and

figure 7 is a flowchart illustrating a method for managing reduced pressure at a tissue site according to an illustrative embodiment of the invention.

Detailed Description

In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which 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 to be 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 present 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.

The illustrative embodiments described herein provide an apparatus and method for managing reduced pressure at a tissue site. Reduced pressure generally refers to a pressure that is less than the ambient pressure at the tissue site being treated. In most cases, this reduced pressure will be less than the atmospheric pressure at the location of the patient. While 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 significantly less than the pressure normally associated with a complete vacuum. Consistent with this nomenclature, an increase in reduced pressure or vacuum pressure refers to a relative decrease in absolute pressure, while a decrease in reduced pressure or vacuum pressure refers to a relative increase in absolute pressure.

The device includes a reduced-pressure source that generates a reduced pressure. The reduced-pressure source is any device capable of generating reduced pressure. Reduced pressure is delivered to the tissue site via a delivery tube. The device includes a single pressure sensor. A pressure sensor is any device capable of measuring or detecting pressure. The single pressure sensor detects the actual reduced pressure at the tissue site. In one embodiment, the single pressure sensor is the only pressure sensor included in the device.

The apparatus also includes a controller. The controller is any device capable of processing data, such as data from a separate pressure sensor. The controller may also control the operation of one or more components of the apparatus. The controller determines a responsiveness of an actual reduced pressure measured by the individual pressure sensor to an increase in reduced pressure generated by the reduced pressure source.

In one embodiment, the reduced pressure source generates a reduced pressure when the actual reduced pressure at the tissue site, as detected by the single pressure sensor, exceeds the target reduced pressure. In another embodiment, the reduced pressure source generates an increased reduced pressure when the target reduced pressure exceeds the actual reduced pressure at the tissue site detected by the single pressure sensor.

The device may also comprise a relief valve (relief valve) connected to the delivery pipe. The pressure reducing valve is any valve capable of reducing the pressure reduction. In this embodiment, the relief valve may open to reduce the actual reduced pressure at the tissue site when the actual reduced pressure at the tissue site detected by the individual pressure sensor exceeds the target reduced pressure by a predetermined threshold.

As used herein, the term "connected" includes being connected via separate objects. For example, if both the pressure reducing valve and the pressure reducing pipe are connected to a third object, the pressure reducing valve may be connected to the delivery pipe. The term "connected" also includes "directly connected," in which case two objects come into contact with each other in some fashion. The term "connected" also encompasses two or more components that are continuous with each other by each component being formed from the same piece of material.

The device includes an indicator. An indicator is any device capable of emitting a signal. For example, the indicator may signal a user of the device. The indicator signals when the controller determines that the actual reduced pressure measured by the single pressure sensor is not responsive to an increase in the reduced pressure generated by the reduced pressure source. "non-responsive" may mean that an increase in reduced pressure generated by the reduced pressure source has no effect on the actual reduced pressure measured by the separate pressure sensor. Additional details regarding the unresponsiveness of the actual reduced pressure measured by the individual pressure sensors will be provided in the illustrative embodiments described below.

The illustrative embodiments also provide a method for managing reduced pressure at a tissue site. The method determines a target reduced pressure. The target reduced pressure may be any reduced pressure set by a user or a device, such as a controller. The method detects an actual reduced pressure at the tissue site using a separate pressure sensor. The process compares the actual reduced pressure to the target reduced pressure to form a comparison. The method performs a reduced pressure management function based on the comparison. A reduced pressure management function is any operation, function, or activity of any or all of the components of the device. For example, the reduced pressure management function may be performed by one or more components of the device. Reduced pressure management functions may also be performed by a user.

In one embodiment, performing the reduced pressure management function based on the comparison includes: the generated reduced pressure generated by the reduced-pressure source is reduced in response to the actual reduced pressure exceeding the target reduced pressure. In another embodiment, the method opens a relief valve that reduces the actual reduced pressure at the tissue site in response to the actual reduced pressure exceeding the target reduced pressure by a predetermined threshold. In another embodiment, the method eliminates the generated reduced pressure by turning off the reduced-pressure source in response to the actual reduced pressure exceeding the target reduced pressure by a predetermined threshold.

In another embodiment, performing the reduced pressure management function based on the comparison includes: the generated reduced pressure generated by the reduced-pressure source is increased in response to the target reduced pressure exceeding the actual reduced pressure. In this embodiment, the method may signal using the indicator in response to the actual reduced pressure at the tissue site being unresponsive to increasing the generated reduced pressure.

In one example, the actual reduced pressure at the tissue site is unresponsive to increasing the generated reduced pressure when the actual reduced pressure at the tissue site fails to increase within a predetermined period of time in response to increasing the generated reduced pressure. In another example, the actual reduced pressure at the tissue site is nonresponsive to increasing the generated reduced pressure when the actual reduced pressure at the tissue site fails to reach the target reduced pressure within the predetermined period of time in response to increasing the generated reduced pressure. In a specific non-limiting example, the predetermined period of time may be in the range of 4 seconds to 6 seconds.

Turning now to fig. 1, a block diagram of an apparatus for managing reduced pressure at a tissue site is depicted in accordance with an illustrative embodiment of the present invention. Specifically, fig. 1 illustrates a reduced pressure treatment system 100 for managing reduced pressure at a tissue site 105.

Reduced pressure treatment system 100 may be used to apply reduced pressure treatment to tissue site 105. Tissue site 105 may be body 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. Although tissue site 105 may include wounds, diseased tissue, or defective tissue, tissue site 105 may further include healthy tissue that is not wounded, diseased, or defective. Applying reduced pressure to tissue site 105 may be used to facilitate drainage of exudates and other liquids from tissue site 105, as well as to facilitate additional tissue growth. In the case where tissue site 105 is a wound site, the growth of granulation tissue and removal of exudates and bacteria can promote wound healing. The application of reduced pressure to non-injured or non-defective tissue, including healthy tissue, may be used to promote the growth of tissue that is excised and transplanted to another tissue site.

The reduced pressure applied to tissue site 105 is generated by reduced pressure source 110. Reduced pressure source 110 may be any type of manually, mechanically, or electrically operated pump. Non-limiting examples of reduced pressure source 110 include devices that are powered by stored energy and are capable of generating a reduced pressure. Examples of such stored energy, reduced pressure sources include, but are not limited to, pumps driven by piezoelectric energy, spring energy, solar energy, kinetic energy, stored energy in capacitors, combustion, and energy generated by Sterling or similar cycles. Other examples of reduced pressure source 110 include manually-activated devices such as bellows pumps (bellows pumps), peristaltic pumps, diaphragm pumps (diaphragmamps), rotary vane pumps, linear piston pumps, pneumatic pumps, hydraulic pumps, hand pumps, foot pumps, and manual pumps such as those used with manually-activated spray bottles. Other devices and methods that may be used or included in reduced pressure source 110 include syringes, lead screws, ratchets, clock-drive devices, swing-drive devices, manual generators, osmotic processes, thermal heating processes, and processes that generate vacuum pressure from condensation.

In another embodiment, reduced pressure source 110 may include a pump driven by a chemical reaction. A tablet, solution, spray, or other delivery mechanism may be delivered to the pump and used to initiate the chemical reaction. The heat generated by the chemical reaction may be used to drive a pump to generate reduced pressure. In another embodiment, pressurized gas bottles (pressurized gas cyclinders) such as CO are used₂The bottle drives the pump to generate reduced pressure. In another embodiment, reduced pressure source 110 may be a battery-driven pump (battery-driven pump). Preferably, the pump uses a small amount of electrical energy and is capable of operating for an extended period of time after a single charge of the battery.

Reduced-pressure source 110 provides reduced pressure to tissue site 105 via dressing 115. Dressing 115 includes a manifold 120, and manifold 120 may be placed adjacent to tissue site 105 or in contact with tissue site 105. Manifold 120 may be a biocompatible, porous material capable of being placed in contact with tissue site 105 and distributing reduced pressure to tissue site 105. Manifold 120 may be made of foam, gauze, felt pads, or any other material suitable for a particular biological application. Manifold 120 may include a plurality of flow channels or paths to facilitate distribution of reduced pressure or fluid to or from tissue site 105.

In one embodiment, manifold 120 is a porous foam and includes a plurality of interconnected cells or pores that function as flow channels. The porous foam may be a polyurethane, open-cell reticulated foam such as GranuFoam produced by Kinetic Concepts, inc. If an open cell foam is used, the porosity may vary, but is preferably from about 400 to 600 microns. The flow channels allow fluid communication throughout the portion of the manifold 120 having open cells. The cells and flow channels may be of uniform shape and size, or may include shaped or randomly varying shapes and sizes. Variations in the shape and size of the cells of the manifold cause variations in the flow channels, and such characteristics can be used to alter the flow characteristics of the fluid through the manifold 120.

In one embodiment, manifold 120 may further include a portion that includes "closed cells. The closed cell portions of manifold 120 comprise a plurality of cells, a majority of which are not in fluid connection with adjacent cells. Closed cell portions may be optionally provided in manifold 120 to prevent fluid transmission through the surrounding surfaces of manifold 120.

Manifold 120 may also be constructed from a bioabsorbable material that does not need to be removed from the patient's body after use of reduced pressure treatment system 100. Suitable bioabsorbable materials can include, but are not limited to: polymeric blends of polylactic acid (PLA) and polyglycolic acid (PGA). The polymerization mixture may also include, but is not limited to: polycarbonate, polyfumarate and caprolactone (capralactone). Manifold 120 may further function as a scaffold for new cell growth, or a scaffold material may be used in conjunction with manifold 120 to promote cell growth. A scaffold is a substance or structure used to promote or improve cell growth or tissue formation, such as a three-dimensional porous structure that provides a template for cell growth. Illustrative examples of scaffold materials include calcium phosphate, collagen, PLA/PGA, coral hydroxyapatite, carbonate, or a treated allograft material (processedallograft material). In one example, the scaffold material has a high porosity (i.e., high air content).

In other embodiments, the manifold 120 may be formed from porous gel or hydrogel-forming materials, textiles such as fabrics, ceramics, laminates, biologics, biopolymers, cork, and hemostatic dressings. Alternatively, the beads may be placed in contact with the tissue site 105 and used to distribute the reduced pressure.

Dressing 115 also includes sealing member 125. Manifold 120 may be secured to tissue site 105 using sealing member 125. Sealing member 125 may be a cover for securing manifold 120 at tissue site 105. While the sealing member 125 may be impermeable or semi-permeable, in one example, the sealing member 125 is capable of maintaining a reduced pressure at the tissue site 105 after the sealing member 125 is installed on the manifold 120. The sealing member 125 may be a flexible drape or film made of a silicone based compound, acrylic, hydrogel or hydrogel-forming material, or any other biocompatible material that includes the desired impermeable or permeable properties of the tissue site 105. The sealing member 125 may be formed of a hydrophobic material to prevent the sealing member 125 from absorbing moisture.

Instead of being provided in a "sheet" form, such as a drape form, the sealing member 125 may be provided in a pourable or sprayable form that is applied to the manifold 120 after the manifold 120 is placed in contact with the tissue site 105. Similarly, sealing member 125 may include devices placed on manifold 120 and tissue site 105 to provide a sealing function, including but not limited to: suction cups, molded castings (molded cases), and bell cups.

In one embodiment, sealing member 125 is configured to provide a sealed connection with tissue surrounding manifold 120 and tissue site 105. The sealing connection may be provided by an adhesive disposed along an edge of sealing member 125 or on any portion of sealing member 125 to secure sealing member 125 to manifold 120 or tissue surrounding tissue site 105. The adhesive may be pre-placed on the sealing member 125 or may be sprayed or otherwise applied to the sealing member 125 immediately prior to installation of the sealing member 125.

As an alternative to an adhesive sealant, a sealing connection may be provided by circumferentially wrapping the area adjacent tissue site 105 with sealing member 125. For example, if tissue site 105 is located on a limb of a patient, an elongated drape or "drape strip" may be wrapped around manifold 120 and the area surrounding tissue site 105 multiple times to provide a sealed connection. Alternatively, the sealed connection between sealing member 125 and the tissue surrounding tissue site 105 may be provided by the reduced pressure applied by reduced pressure treatment system 100. In this embodiment, the perimeter of the sealing member 125 may be a "vacuum" that seals to the patient's skin. In another embodiment, sealing member 125 may be sutured to tissue surrounding tissue site 105 to provide a sealed connection.

In some cases, sealing member 125 may not be required to seal tissue site 105. For example, tissue site 105 can be "self-sealing" to maintain reduced pressure. In the case of subcutaneous and deep tissue wounds, cavities, and fistulas, maintaining reduced pressure at tissue site 105 may not utilize sealing member 125. Because tissue often surrounds or surrounds these types of tissue sites, the tissue surrounding the tissue site can effectively function as a sealing member.

The reduced pressure generated by reduced pressure source 110 may be applied to tissue site 105 using source tube 130 and delivery tube 135. Source tube 130 and delivery tube 135 may be any tube through which a gas, liquid, gel, or other fluid may flow. For example, effluent from tissue site 105 may flow through delivery tube 135. In fig. 1, source line 130 connects reduced pressure source 110 to canister 140, and delivery tube 135 connects canister 140 to dressing 115. However, in another embodiment, reduced pressure source 110 may be directly connected to dressing 115 using delivery tube 135.

Source tube 130 and delivery tube 135 may be made of any material. Source tube 130 and delivery tube 135 may be flexible or non-flexible. Likewise, source tube 130 and delivery tube 135 may include one or more pathways or lumens through which fluid may flow. For example, delivery tube 135 may include two lumens. In this example, one lumen may be used to deliver exudate from tissue site 105 to canister 140. Another lumen may be used to deliver fluids such as air, antibacterial agents, antiviral agents, cell growth promoters, irrigation fluids, or other chemically active agents to tissue site 105. The fluid sources from which these fluids originate are not shown in fig. 1. Additional details regarding the inclusion of a multi-lumen tube in reduced pressure treatment system 100 are provided below.

In one embodiment, delivery tube 135 is connected to manifold 120 via a connecting member 145. Connecting member 145 allows fluid to be delivered from manifold 120 to delivery tube 135, and vice versa. For example, using manifold 120, exudate collected from tissue site 105 may enter delivery tube 135 via connecting member 145. In another embodiment, reduced pressure treatment system 100 does not include connection member 145. In this embodiment, delivery tube 135 may be inserted directly into sealing member 125 or manifold 120 such that the end of delivery tube 135 is adjacent to manifold 120 or in contact with manifold 120.

Reduced pressure treatment system 100 includes canister 140. Liquid, such as effluent from tissue site 105, may flow through delivery tube 135 into canister 140. The tank 140 may be any device or chamber capable of containing fluids, such as gases and liquids, as well as fluids containing solids. For example, canister 140 may contain effluent from tissue site 105. Source tube 130 and delivery tube 135 may be directly connected to canister 140, or may be connected to canister 140 via a connector, such as connector 150.

The canister 140 may be a flexible or rigid canister, bag, or pouch fluidly connected to the manifold 120 by a delivery tube 135. The tank 140 may be a separate vessel or may be operably combined with the reduced pressure source 110 to collect effluent and fluids. In the illustrative embodiment in which a manual pump, such as a bellows pump, is used as reduced pressure source 110, the variable volume chamber that creates reduced pressure may also function as canister 140, collecting fluid as the chamber expands. The canister 140 may include a single chamber for collecting fluid, or alternatively may include multiple chambers. A desiccant or absorbent material may be placed within the canister 140 to capture or control the fluid after it has been collected. In the absence of the tank 140, methods for controlling effluent and other fluids may be applied, wherein fluids, particularly those that are water soluble, are allowed to evaporate from the manifold 120.

Reduced pressure treatment system 100 includes a pressure sensor 155. Pressure sensor 155 detects the actual reduced pressure at tissue site 105. In one non-limiting example, the pressure sensor 155 is a silicon piezoresistive gauge pressure sensor (silicon piezoresistive gauge pressure sensor). In one embodiment, pressure sensor 155 is the only pressure sensor included in reduced pressure treatment system 100. In this embodiment, reduced pressure treatment system 100 does not include a pressure sensor other than pressure sensor 155.

Pressure sensor 155 detects reduced pressure at tissue site 105 via control tube 160. Control tube 160 is any tube through which gas can flow. Control tube 160 may be made of any material. Control tube 160 may be flexible or non-flexible. Likewise, control tube 160 may include one or more pathways or lumens through which fluid may flow.

In fig. 1, control tube 160 is shown passing through connector 150. However, the arrangement of the control tube 160 may be varied to suit particular needs and uses. For example, the control tube 160 may be routed through the canister 140, along an outside surface of the canister 140, or may bypass the canister 140. The end of control tube 160 opposite pressure sensor 155 may be connected to manifold 120 via connector 145. In another example, control tube 160 may be inserted directly into sealing member 125 or manifold 120 such that an end of control tube 160 is adjacent to manifold 120 or in contact with manifold 120.

In another embodiment, delivery tube 135 and control tube 160 are each lumens in a single multi-lumen tube. Each of source tube 130 and control tube 160 may also be lumens in a single multi-lumen tube. In examples in which reduced pressure source 110 is connected to manifold 120 using only delivery tube 135, a single multi-lumen tube may be used to connect both reduced pressure source 110 and pressure sensor 155 to manifold 120. Additional details regarding the multi-lumen embodiment are provided in fig. 2 and 3 below.

Pressure sensor 155 may be located anywhere on reduced pressure treatment system 100. In fig. 1, pressure sensor 155 is shown remote from tissue site 105. In this example, the reduced pressure at tissue site 105 may be detected by remotely located pressure sensor 155 through control tube 160, which control tube 160 allows gas flow. Also in this example, the pressure sensor may be directly or indirectly connected to other remotely disposed components of the reduced pressure treatment system 100, such as the reduced pressure source 110, the canister 140, or any other illustrated component of the reduced pressure treatment system 100. In another example, pressure sensor 155 may be positioned adjacent to tissue site 105. In this example, pressure sensor 155 may not require the use of control tube 160 to detect the pressure at tissue site 105. In one non-limiting example, pressure sensor 155 is directly connected to manifold 120 or is placed between sealing member 125 and manifold 120.

Reduced pressure treatment system 100 includes a control tube valve 165. Control tube valve 165 may be connected to control tube 160. Control tube valve 165 may be any valve capable of relieving reduced pressure in control tube 160. Non-limiting examples of control tube valve 165 include a pneumatic solenoid valve, a proportional valve, or a mechanical valve.

In one example, control tube valve 165 may be manually controlled by a human hand. In another example, control tube valve 165 may be controlled by controller 170. In one embodiment, upon detection of a blockage in control tube 160, control tube valve 165 may be opened to relieve the reduced pressure in control tube 160. Such occlusion may occur, for example, when an outflow or other fluid from the tissue site 105 clogs the control tube 160. By relieving the reduced pressure in control tube 160 via control tube valve 165, the occlusion may be cleared from control tube 160.

Reduced pressure treatment system 100 also includes a pressure relief valve 175. Relief valve 175 may be a valve connected to any one or any combination of source tube 130, canister 140, connector 150, delivery tube 135, connector 145, reduced pressure source 110, or dressing 115. Relief valve 175 may be any type of valve capable of relieving the reduced pressure at tissue site 105. Non-limiting examples of pressure relief valve 175 include a pneumatic solenoid valve, a proportional valve, or a mechanical valve. In one example, relief valve 175 may open to relieve the reduced pressure at tissue site 105. Relief valve 175 may also be used to manage the reduced pressure at tissue site 105. Additional details regarding the use of relief valve 175 and other components of reduced pressure treatment system 100 to manage reduced pressure at tissue site 105 are provided below.

The reduced pressure treatment system includes a controller 170. Controller 170 is any device capable of processing data, such as data from pressure sensor 155. Controller 170 may also control the operation of one or more components of reduced pressure treatment system 100, such as reduced pressure source 110, pressure relief valve 175, control tube valve 165, pressure sensor 155, or indicator 180. In one embodiment, controller 170 receives and processes data, such as data from pressure sensor 155, and controls operation of one or more components of reduced pressure treatment system 100 to manage reduced pressure at tissue site 105.

In one embodiment, controller 170 determines a target reduced pressure for tissue site 105. The target reduced pressure may be a user-definable reduced pressure for tissue site 105. The target reduced pressure may also be determined by the controller 170. In one example, the target reduced pressure is a reduced pressure that provides effective treatment of tissue site 105 and takes into account safety considerations associated with applying the reduced pressure to tissue site 105.

In one example, pressure sensor 155 detects reduced pressure at tissue site 105. The reduced pressure measurement may be received by controller 170 from pressure sensor 155. Controller 170 may compare the reduced pressure received from pressure sensor 155 to a target reduced pressure to compare. Controller 170 may then execute or direct components of reduced pressure treatment system 100 to perform reduced pressure management functions based on the comparison.

In one embodiment, controller 170, in performing the reduced pressure management function based on the comparison, reduces the generated reduced pressure generated by reduced pressure source 110 in response to the actual reduced pressure exceeding the target reduced pressure. For example, if reduced pressure source 110 is a motorized or other form of electrically operated reduced pressure source, the motor or electrical process may be slowed such that reduced pressure source 110 generates a reduced amount of reduced pressure. In another non-limiting example, if reduced pressure source 110 is a chemically driven reduced pressure source, the chemical process driving reduced pressure source 110 may be slowed or changed to reduce the amount of reduced pressure generated by reduced pressure source 110.

In another embodiment, controller 170 opens relief valve 175 to reduce the reduced pressure at tissue site 105 in response to the actual reduced pressure measured by pressure sensor 155 exceeding the target reduced pressure by a predetermined threshold. The predetermined threshold may be determined by a user or by a component of reduced pressure treatment system 100, such as controller 170. In one example, the predetermined threshold is a threshold that helps ensure safety at tissue site 105. For example, the predetermined threshold may be determined such that an actual reduced pressure at tissue site 105 that exceeds the target reduced pressure by the predetermined threshold may affect safety at tissue site 105. Thus, this embodiment may be implemented as a safety mechanism using a separate pressure sensor 155.

In another embodiment, controller 170 turns off or shuts down reduced pressure source 110 in response to the actual reduced pressure measured by pressure sensor 155 exceeding the target reduced pressure by a predetermined threshold. Turning off or turning off reduced pressure source 110 may reduce the reduced pressure at tissue site 105. In one example, the predetermined threshold beyond which reduced pressure source 110 is closed is greater than or less than the predetermined threshold beyond which relief valve 175 is opened as described in the previous embodiments. Thus, in this example, a two-tiered safety mechanism (two-tiered safety mechanism) is applied to ensure the safety of tissue at tissue site 105. In another example, the predetermined threshold beyond which reduced pressure source 110 is turned off is the same as the predetermined threshold beyond which relief valve 175 is opened.

In another example, controller 170 increases the generated reduced pressure generated by reduced pressure source 110 when performing a reduced pressure management function based on the comparison. For example, if reduced pressure source 110 is a motorized or otherwise electrically operated reduced pressure source, the cadence of the motor or electrical process may be increased such that reduced pressure source 110 generates an increased amount of reduced pressure. In another non-limiting example, if reduced pressure source 110 is a chemically driven reduced pressure source, the chemistry driving reduced pressure source 110 may be accelerated or altered to increase the amount of reduced pressure generated by reduced pressure source 110.

In another embodiment, controller 170 determines the responsiveness of the actual reduced pressure at tissue site 105 measured by pressure sensor 155 to an increase in the generated reduced pressure from reduced pressure source 110. In one example, the controller 170 may detect when the reduced pressure generated by the reduced pressure source is increased or decreased. For example, controller 170 may be able to detect when the motor speed, chemical reaction speed, or compression speed of reduced pressure source 110 has increased or decreased. Other parameters that may be detected by controller 170 to determine such an increase or decrease include the current tractive effort of the motor, which may be indicative of the load of the pump. The level of power or pulse width modulation required for a given motor to deliver the desired reduced pressure to tissue site 105 may also be detected. Controller 170 may also be capable of inferring whether the reduced pressure generated by the reduced pressure source has increased or decreased based on a comparison between the actual reduced pressure measured by pressure sensor 155 and the target reduced pressure.

In one embodiment, controller 170 commands indicator 180 to emit a signal in response to the actual reduced pressure at tissue site 105 measured by pressure sensor 155 being unresponsive to increasing the generated reduced pressure. In one embodiment, the indicator 180 is a light emitting diode, or "LED". In this embodiment, indicator 180 illuminates in response to the actual reduced pressure at tissue site 105 being unresponsive to increasing the generated reduced pressure.

In another embodiment, the indicator 180 is an acoustic emission device (sound emitting device) such as a speaker. In this embodiment, indicator 180 emits a sound in response to actual reduced pressure at tissue site 105 being unresponsive to increasing the generated reduced pressure.

In another embodiment, the actual reduced pressure at tissue site 105 is nonresponsive to increasing the generated reduced pressure when the actual reduced pressure at tissue site 105 fails to increase within a predetermined period of time in response to increasing the generated reduced pressure. Such non-responsiveness may indicate that one or more components of reduced pressure treatment system 100, such as delivery tube 135 or source tube 130, are blocked or have a leak. For example, a liquid, such as effluent from tissue site 105, may block delivery tube 135 or source tube 130. In another example, a rupture may occur at a location along delivery tube 135 or source tube 130.

The predetermined time period may be any time period and may be set by a user of reduced pressure treatment system 100 or a component of reduced pressure treatment system 100, such as controller 170. In one example, the predetermined time period is in a range of one second to ten seconds or four seconds to six seconds. In one specific non-limiting example, the predetermined period of time is five seconds.

In another embodiment, the actual reduced pressure at tissue site 105 is nonresponsive to increasing the generated reduced pressure when the actual reduced pressure at tissue site 105 fails to reach the target reduced pressure within a predetermined period of time in response to increasing the generated reduced pressure. Similar to the previously described embodiments, such non-responsiveness may indicate that one or more components of reduced pressure treatment system 100, such as delivery tube 135 or source tube 130, are blocked or have a leak.

In another embodiment of the present invention, if reduced pressure source 110 is a vacuum pump and a motor, a sensor may be coupled to the vacuum pump or motor to measure the speed of the pump or motor. The measurements taken by the sensors can be used to infer the pressure delivered by the pump, thereby providing a means for determining whether a leak or blockage is present and distinguishing between leaks or blockages (mechanism). For example, detection of a leak may be performed by monitoring the speed of one or both of the pump or the motor. If a leak occurs while reduced pressure treatment is being applied, one or both of the pump speed or motor speed may increase indicating that the pump is generating more reduced pressure. If a blockage occurs, the speed of one or both of the pump or motor will likely decrease. The output from the pump or motor speed sensor may be used by the controller 170 to transmit a signal using the indicator 180 during a leak or blockage condition.

In one particular illustrative example, reduced pressure source 110 includes a motor having a speed. In this example, the sensor may detect the speed of the motor. Indicator 180 may emit a signal when the speed of the motor changes by a threshold amount. The threshold amount may be any amount and may be set by a user of reduced pressure treatment system 100 or by a component of reduced pressure treatment system 100, such as controller 170. The threshold amount may be expressed in a finite number, percentage, or any combination thereof.

Turning now to FIG. 2, a perspective view of a multi-lumen tube is depicted in accordance with an illustrative embodiment of the present invention. Specifically, figure 2 depicts multi-lumen tube 200, which may be implemented in a reduced pressure treatment system, such as reduced pressure treatment system 100 in figure 1.

Multi-lumen tube 200 includes two lumens. Specifically, multi-lumen tube 200 includes lumens 235 and 260. Although multi-lumen tube 200 includes two lumens 235 and 160, the multi-lumen tube may have any number of lumens, such as 3, 4, or 10.

In one embodiment, one of lumens 235 and 260, such as lumen 235, is a delivery tube or source tube, such as delivery tube 135 and source tube 130 in FIG. 1. In another embodiment, one of lumens 235 and 260, such as lumen 260, is a control tube, such as control tube 160 in FIG. 1. By combining the combination of the delivery tube, source tube, and control tube into lumens in a single multi-lumen tube, the number of separate tubes included in a reduced pressure treatment system may be reduced. The reduced number of tubes simplifies the use of the reduced pressure treatment system by the user and reduces the burden of carrying the reduced pressure treatment system.

Turning now to FIG. 3, a perspective view of a multi-lumen tube is depicted in accordance with an illustrative embodiment of the present invention. In particular, figure 3 depicts multi-lumen tube 300, which may be implemented in a reduced pressure treatment system, such as reduced pressure treatment system 100 in figure 1. Multi-lumen tube 300 may be a non-limiting example of multi-lumen tube 200 in figure 2.

Multi-lumen tube 300 includes nine lumens. Specifically, multi-lumen tube 300 includes lumen 335 and peripheral lumen 360. Although multi-lumen tube 300 shows peripheral lumen 360 as surrounding lumen 335, the lumens in multi-lumen tube 300 may have any spatial configuration with respect to each other.

In one embodiment, one of lumens 335 and 360, such as lumen 335, is a delivery tube or source tube, such as delivery tube 135 and source tube 130 in FIG. 1. In another embodiment, one of lumens 335 and 360, such as either or both of lumens 360, is a control tube, such as control tube 160 shown in fig. 1. Similar to multi-lumen tube 300 in fig. 3, by incorporating any combination of delivery, source and control tubes as lumens in multi-lumen tube 300, the number of separate tubes included in the reduced pressure treatment system may be reduced to increase the usability of the reduced pressure treatment system in which the multi-lumen tube is included.

Turning now to fig. 4, a flowchart illustrating a method for managing reduced pressure at a tissue site is depicted in accordance with an illustrative embodiment of the present invention. The method illustrated in figure 4 may be implemented by a controller, such as controller 170 in figure 1, in conjunction with other components of a reduced pressure treatment system, such as components of reduced pressure treatment system 100 in figure 1.

The process begins by determining a target reduced pressure (step 405). The method detects an actual reduced pressure at the tissue site using a separate pressure sensor (step 410). The process compares the actual reduced pressure to the target reduced pressure to form a comparison (step 415). The method performs a reduced pressure management function based on the comparison (step 420).

Turning now to fig. 5, a flowchart illustrating a method for managing reduced pressure at a tissue site is depicted in accordance with an illustrative embodiment of the present invention. The method illustrated in figure 5 may be implemented by a controller, such as controller 170 in figure 1, in conjunction with other components of a reduced pressure treatment system, such as components of reduced pressure treatment system 100 in figure 1. The method illustrated in fig. 5 provides illustrative embodiments and additional details regarding steps 415 and 420 of fig. 4.

The process begins by determining whether the actual reduced pressure exceeds the target reduced pressure (step 505). If the process determines that the actual reduced pressure does not exceed the target reduced pressure, the process terminates. Returning to step 505, if the process determines that the actual reduced pressure exceeds the target reduced pressure, the process reduces the generated reduced pressure generated by the reduced pressure source (step 510).

The process determines whether the actual reduced pressure exceeds the target reduced pressure by a predetermined threshold (step 515). If the process determines that the actual reduced pressure does not exceed the target reduced pressure by the predetermined threshold, the process terminates. Returning to step 515, if the process determines that the actual reduced pressure exceeds the target reduced pressure by a predetermined threshold, the process determines whether to reduce the reduced pressure by opening the pressure relief valve (step 520). If the process determines to reduce the reduced pressure by opening the relief valve, the process opens the relief valve to reduce the actual reduced pressure at the tissue site (step 525).

Returning to step 520, if the process determines that the reduced pressure is not to be reduced by opening the pressure reduction valve, the process determines whether to reduce the reduced pressure by closing the pressure reduction source (step 530). If the process determines to reduce the reduced pressure by turning off the reduced pressure source, the process turns off the reduced pressure source (step 535). The method then terminates. Returning to step 530, if the process determines that the reduced pressure is not to be reduced by turning off the reduced pressure source, the process terminates.

Turning to fig. 6, a flowchart illustrating a method for managing reduced pressure at a tissue site is depicted in accordance with an illustrative embodiment of the present invention. The method illustrated in figure 6 may be implemented by a controller, such as controller 170 in figure 1, in conjunction with other components of a reduced pressure treatment system, such as components of reduced pressure treatment system 100 in figure 1. The method illustrated in fig. 5 provides illustrative embodiments and additional details regarding steps 415 and 420 of fig. 4.

The process begins by determining whether the target reduced pressure exceeds the actual reduced pressure (step 605). If the process determines that the target reduced pressure does not exceed the actual reduced pressure, the process terminates. Returning to step 605, if the process determines that the target reduced pressure exceeds the actual reduced pressure, the process increases the generated reduced pressure generated by the reduced pressure source (step 610).

The method determines whether the actual reduced pressure measured by the individual pressure sensors is responsive to the increased generated reduced pressure (step 615). If the process determines that the actual reduced pressure measured by the individual pressure sensors is responsive to the increased generated reduced pressure, the process terminates. Returning to step 615, if the process determines that the actual reduced pressure measured by the individual pressure sensor is not responsive to the increased generated reduced pressure, the process transmits a signal using an indicator (step 620). The method then terminates.

Turning now to fig. 7, a flowchart illustrating a method for managing reduced pressure at a tissue site is depicted in accordance with an illustrative embodiment of the present invention. The method illustrated in figure 7 may be implemented by a controller, such as controller 170 in figure 1, in conjunction with other components of a reduced pressure treatment system, such as components of reduced pressure treatment system 100 in figure 1. The method illustrated in fig. 7 provides illustrative embodiments and additional details regarding steps 615 and 620 of fig. 6.

The method begins by determining whether the actual reduced pressure at the tissue site increases within a predetermined period of time (step 705). If the method determines that the actual reduced pressure at the tissue site has not increased within a predetermined period of time, the method transmits a signal using an indicator (step 710). The method then terminates.

Returning to step 705, if the process determines that the actual reduced pressure at the tissue site increases within a predetermined period of time, the process determines whether the actual reduced pressure at the tissue site reaches the target reduced pressure within the predetermined period of time (step 715). If the method determines that the actual reduced pressure at the tissue site has not reached the target reduced pressure within a predetermined period of time, the method transmits a signal using an indicator (step 710). The method then terminates. Returning to step 715, if the process determines that the actual reduced pressure at the tissue site meets the target reduced pressure within a predetermined period of time, the process then terminates.

The flowcharts and block diagrams in the different depicted embodiments illustrate the architecture, functionality, and operation of some possible implementations of apparatus and methods. In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, in some cases, two blocks shown in succession may be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved.

These illustrative embodiments may be configured as a lightweight and low cost system that consumes less electrical energy than currently used reduced pressure treatment systems. The reduction in size and weight is particularly important when the system is used to treat low severity wounds and wounds of ambulatory patients. These wounds, as well as the patient, require a non-invasive and lightweight system to minimize discomfort and movement obstruction of the patient.

One way to minimize cost, weight and power consumption is by using only one sensor to measure pressure. As previously mentioned, conventional systems typically use two pressure sensors, one to measure the pressure at the tissue site and one to measure the pressure of the reduced pressure source. However, the elimination of a pressure sensor that measures the pressure of the reduced pressure source allows the amount of electronic circuitry required and the amount of electrical energy consumed by the system to be significantly reduced. In addition, any circuitry and software for comparing the two sensor readings is eliminated. In addition, the illustrative embodiments enable a predetermined reduced pressure to be applied to tissue while providing detection and notification of certain abnormal system conditions using fewer components than prior systems.

The illustrative embodiments also eliminate the need to approximate the pressure at the tissue site using measurements from a reduced pressure source. Further, when included with the other features of the illustrative embodiments, directly determining the pressure at the tissue site allows the reduced pressure treatment system to detect leaks and blockages by observing pressure changes at the tissue site in response to operational changes made at the reduced pressure source.

Claims (21)

1. An apparatus for managing reduced pressure at a tissue site, the apparatus comprising:

a reduced-pressure source that generates a reduced pressure that is delivered to the tissue site via a delivery tube;

a separate pressure sensor connected to the control tube and operable to detect actual reduced pressure at the tissue site;

a controller connected to the separate pressure sensor and the reduced-pressure source, the controller configured to detect a change in an operating parameter of the reduced-pressure source indicative of a change in the reduced pressure generated by the reduced-pressure source, the controller further configured to determine a responsiveness of an actual reduced pressure measured by the separate pressure sensor to an increase in the reduced pressure generated by the reduced-pressure source;

an indicator that emits a signal when the controller determines that the actual reduced pressure measured by the separate pressure sensor is not responsive to an increase in the reduced pressure generated by the reduced pressure source; and is

Wherein the unresponsive condition is determined by at least one of:

(1) monitoring whether the actual reduced pressure at the tissue site increases over a predetermined period of time, and

(2) monitoring whether the actual reduced pressure at the tissue site reaches a target reduced pressure within a predetermined period of time.

2. The apparatus of claim 1, wherein the reduced pressure source generates a reduced pressure when an actual reduced pressure at the tissue site detected by the single pressure sensor exceeds a target reduced pressure.

3. The apparatus of claim 1, further comprising:

a relief valve connected to the delivery tube, the relief valve opening to reduce the actual reduced pressure at the tissue site when the actual reduced pressure at the tissue site detected by the single pressure sensor exceeds a target reduced pressure by a predetermined threshold.

4. The apparatus of claim 1, wherein the reduced pressure source generates an increased reduced pressure when a target reduced pressure exceeds an actual reduced pressure at the tissue site detected by the single pressure sensor.

5. The apparatus of claim 1, further comprising:

a control tube, wherein the separate pressure sensor detects actual reduced pressure at the tissue site via the control tube; and

a control tube relief valve connected to the control tube, the control tube relief valve relieving a reduced pressure in the control tube when a blockage in the control tube is detected.

6. The apparatus of claim 5, further comprising:

a manifold, wherein the single pressure sensor detects actual reduced pressure at the tissue site through the control tube via the manifold.

7. The device of claim 5, wherein the control tube is a first lumen, wherein the delivery tube is a second lumen, and wherein the first lumen and the second lumen are in separate multi-lumen tubes.

8. The apparatus of claim 1, wherein the indicator is a light emitting diode, and wherein the signal is illumination of the light emitting diode.

9. The device of claim 1, wherein the device does not include a pressure sensor other than the single pressure sensor.

10. The apparatus of claim 1, wherein the reduced-pressure source comprises a motor having a speed.

11. The apparatus of claim 10, wherein a sensor detects a speed of the motor, and wherein the indicator emits a signal when the speed of the motor changes by a threshold amount.

12. A method for managing reduced pressure at a tissue site, the method comprising:

determining a target reduced pressure;

detecting an actual reduced pressure at the tissue site using a separate pressure sensor;

comparing the actual reduced pressure to the target reduced pressure to form a comparison of the pressure data; and

performing a reduced pressure management function based on the comparison;

wherein the step of performing a reduced pressure management function based on the comparison comprises:

increasing the reduced pressure generated by the reduced pressure source in response to the target reduced pressure exceeding the actual reduced pressure; and

an indicator is used to emit a signal when the actual reduced pressure at the tissue site is unresponsive to increasing the reduced pressure generated by the reduced pressure source.

13. The method of claim 12, wherein performing a reduced pressure management function based on the comparison further comprises:

reducing the reduced pressure generated by the reduced pressure source in response to an actual reduced pressure exceeding a target reduced pressure.

14. The method of claim 13, further comprising:

a relief valve that reduces the actual reduced pressure at the tissue site is opened in response to the actual reduced pressure exceeding the target reduced pressure by a predetermined threshold.

15. The method of claim 13, further comprising:

the generated reduced pressure is eliminated by turning off the reduced pressure source in response to the actual reduced pressure exceeding a target reduced pressure by a predetermined threshold.

16. The method of claim 12, wherein the actual reduced pressure at the tissue site is nonresponsive to increasing the reduced pressure generated by the reduced pressure source when the actual reduced pressure at the tissue site fails to increase within a predetermined period of time in response to increasing the reduced pressure generated by the reduced pressure source.

17. The method of claim 12, wherein the actual reduced pressure at the tissue site is nonresponsive to increasing the reduced pressure generated by the reduced pressure source when the actual reduced pressure at the tissue site fails to reach the target reduced pressure within a predetermined period of time in response to increasing the reduced pressure generated by the reduced pressure source.

18. The method of claim 17, wherein the predetermined period of time is in a range of 4 seconds to 6 seconds.

19. A method for managing reduced pressure at a tissue site, the method comprising:

detecting, using a controller, a change in an operating parameter of a reduced-pressure source, the change in the operating parameter of the reduced-pressure source being indicative of a change in reduced pressure generated by the reduced-pressure source;

determining an actual reduced pressure at the tissue site using a separate pressure sensor;

emitting a signal using an indicator when an actual reduced pressure at a tissue site is unresponsive to increasing the reduced pressure; and is

Wherein the unresponsive condition is determined by at least one of:

(1) monitoring whether the actual reduced pressure at the tissue site increases over a predetermined period of time, and

(2) monitoring whether the actual reduced pressure at the tissue site reaches a target reduced pressure within a predetermined period of time.

20. The method of claim 19, further comprising:

determining the target reduced pressure for the tissue site; and

comparing the actual reduced pressure detected by the single pressure sensor to a target reduced pressure.

21. The method of claim 20, further comprising:

reducing the reduced pressure generated by the reduced pressure source in response to the actual reduced pressure exceeding a target reduced pressure.