HK1158119A - 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.

Description

Reduced-pressure treatment system with reservoir control

Cross Reference to Related Applications

The present invention is in accordance with the benefit of 35 U.S. C. § 119(e) U.S. provisional patent application serial No. 61/087,377 entitled "A Reduced-Pressure Treatment System with Reservoir Control", filed 8/2008, 61/087,377, which is incorporated herein by reference for all purposes.

Background

The present invention relates generally to medical treatment systems and devices, and more particularly, to reduced-pressure treatment systems with reservoir control.

Treatment of wounds is sometimes problematic. Appropriate 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 kept away from the wound.

More recently, reduced pressure has been used to help treat wounds and remove fluids including exudates. In many instances, reduced pressure has been applied using negative pressure devices that include a foam pad placed on or within the wound surface and fluidly coupled to a reduced pressure source. The reduced-pressure source has typically involved a vacuum pump that, when activated, delivers reduced pressure to the foam pad such that fluid is removed from the wound through the foam pad and transported through a conduit to a fluid reservoir, such as a canister. The reservoir collects and retains fluid removed from operation of the treatment system. When the reservoir is filled with the removed fluid, the reservoir is emptied and the system is re-accessed or replaced. Efforts have been made to alert the patient when the reservoir is full.

Brief summary

The invention shown and described in various illustrative embodiments herein addresses deficiencies in certain aspects of reduced pressure treatment systems and systems for alerting a patient that a reservoir is full. According to an illustrative embodiment, a reduced pressure treatment system for treating a tissue site on a patient includes: a manifold member for placement adjacent a tissue site, an over-drape (over-drape) for providing a fluid seal over the manifold member and a patient, and a reduced-pressure subsystem for delivering a reduced pressure over the over-drape. The reduced-pressure subsystem includes: a reservoir having an interior space operable to contain a fluid, a reduced-pressure delivery conduit in fluid communication with the interior space for delivering a reduced pressure up the 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 also includes a reduced-pressure source in fluid communication with the source conduit and operable to deliver a reduced pressure to the source conduit, and a reduced-pressure control unit associated with the pressure sensor and the reduced-pressure source. The reduced-pressure control unit is operable to receive pressure data from the pressure sensor and supply data (supply data) from the reduced-pressure source and determine when a reservoir full/plugged condition exists.

According to another illustrative embodiment, a reduced-pressure system for providing reduced pressure and for receiving a fluid includes: a reservoir having an interior space operable to contain a fluid, a reduced-pressure delivery conduit in fluid communication with the interior space for delivering a reduced pressure, a source conduit in fluid communication with the interior space, and a pressure sensor conduit in fluid communication with the interior space. The reduced-pressure system also includes a pressure sensor in fluid communication with the pressure sensor conduit and a reduced-pressure source in fluid communication with the source conduit and operable to deliver reduced pressure to the source conduit. The reduced-pressure system also includes a reduced-pressure control unit associated with the pressure sensor and the reduced-pressure source and operable to receive pressure data from the pressure sensor and supply data from the reduced-pressure source and determine when a reservoir full/blocked condition exists.

According to another illustrative embodiment, a reduced-pressure system includes a reservoir housing forming an interior space and a reduced-pressure source for delivering reduced pressure. A reduced-pressure source is fluidly coupled to the interior space of the reservoir and is operable to deliver reduced pressure to the interior space. The reduced pressure source is responsive to the control signal. The reduced-pressure system also includes a supply sensor (supply sensor) for measuring a supply rate of reduced pressure and operable to generate 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 generate a signal P indicative of a pressure level in the pressure sensor conduit adjacent the pressure sensor. The reduced-pressure system also includes a reduced-pressure control unit coupled to the supply sensor, the pressure sensor, and the reduced-pressure source. The reduced-pressure control unit is operable to receive a signal I from the supply sensor and a 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 cause the reduced-pressure source to shut off when the reservoir is full.

According to another illustrative embodiment, a method of detecting a fill state of a reservoir for treating a patient with a reduced-pressure treatment system includes the steps of: the method includes generating a reduced pressure in fluid communication with a reduced-pressure treatment system, applying the reduced pressure to the tissue site, collecting fluid from the tissue site in a reservoir, and monitoring the pressure within the reservoir. The method further includes terminating the application of reduced pressure when the pressure in the reservoir falls below the selected absolute value for a specified time interval. The reservoir has a pressure sensor conduit in fluid communication with the reservoir and a supply conduit in fluid communication with the reservoir. The step of monitoring the pressure within the reservoir includes monitoring the pressure within the pressure sensor conduit.

According to another illustrative embodiment, a method of manufacturing a reduced-pressure system includes the steps of: a reservoir is formed having an interior space operable to contain a fluid and a reduced-pressure delivery conduit is fluidly coupled to the interior space. The reduced-pressure delivery conduit is for delivering reduced pressure to the delivery site. The method of manufacture further comprises: a source conduit is fluidly coupled to the interior space, a pressure sensor conduit is fluidly coupled to the interior space, and a pressure sensor is fluidly coupled to the pressure sensor conduit. The method may further comprise: a reduced-pressure source is provided that is responsive to the control signal, a reduced-pressure source is coupled to the source conduit, and a reduced-pressure control unit is provided. The reduced-pressure control unit is operable to receive pressure data from the pressure sensor and supply data from the reduced-pressure source and determine when a reservoir full/plugged condition exists.

Other features and advantages of the illustrative embodiments will become apparent with reference to the drawings and detailed description that follow.

Brief Description of Drawings

A more complete understanding of the present systems, methods, and devices may be acquired by referring to the following detailed description when taken in conjunction with the accompanying drawings, wherein:

figure 1 is a schematic perspective view of an illustrative embodiment of a reduced-pressure treatment system with reservoir control, with portions shown in cross-section;

figure 2A is a schematic diagram of an illustrative embodiment of a reduced-pressure treatment system with reservoir control, with portions shown in cross-section;

FIGS. 2B and 2C are schematic front cross-sectional views of a portion of the reduced-pressure system of FIG. 2A;

figure 3 is a representative diagram showing illustrative operating parameters of a reduced pressure treatment system according to an illustrative embodiment;

FIG. 4 is a schematic diagram of an illustrative embodiment of a reduced pressure control unit; and

figure 5 is an illustrative flow diagram of one possible approach to incorporating the logic of a reduced pressure control unit in an illustrative embodiment.

Detailed description of the preferred embodiments

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. The description may omit certain information known to those skilled in the art, in order to avoid detail not necessary to enable those skilled in the art to practice the invention. 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.

Referring to fig. 1, an illustrative embodiment of a reduced pressure treatment system 100 for treating a tissue site 106, such as a wound 104. The tissue site 106 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. As used herein, "or" does not require mutual exclusivity unless otherwise indicated. The wound 104 may take many possible shapes and degrees, but is shown in this illustrative embodiment as a linear wound from, for example, surgery, through a portion of the epidermis 108, dermis 110, and into the subcutaneous tissue 112. In this embodiment, the reduced pressure treatment system 100 is shown as being applied over the epidermis 108 and covering the wound 104, but it will be appreciated that the reduced pressure treatment system 100 may be used for open wounds (open wind) and may be placed partially below the epidermis in the wound bed. The reduced pressure treatment system 100 may include a manifold member 114, a sealing subsystem 116, and a reduced pressure subsystem 126. The reduced pressure treatment system 100 may be constructed at a relatively lower cost compared to conventional systems, achieve better mechanical reliability, and operate in multiple orientations without false alarms.

In one illustrative embodiment, the manifold member 114 is fabricated from a porous and permeable foam-like material, and more specifically, a reticulated open cell polyurethane or polyether foam that allows good permeability of wound fluids under reduced pressure. One such foam material that has been used is VAC available from Kinetic Concepts Inc. (KCI) of san Antonio, TexasGranuFoamA dressing is provided. Any material or combination of materials may be used for the manifold material, so long as the manifold material is operable to distribute reduced pressure. As used hereinThe term "manifold" is used to generally refer to a substance or structure provided to assist in applying reduced pressure to, delivering fluids to, or removing fluids from a tissue site. The manifold typically includes a plurality of flow channels or pathways that distribute fluid provided to and removed from the area of tissue surrounding the manifold. Multiple flow paths may be interconnected. Examples of manifolds may include, but are not limited to: tools having structural elements arranged to form flow channels, cellular foams such as open cell foams, porous tissue aggregates, and liquids, gels, and foams that include or cure to include flow channels. The manifold material may also be a combination or layering of materials. For example, a first manifold layer of hydrophilic foam may be disposed adjacent a second manifold layer of hydrophobic foam to form the manifold member 114.

GranuFoam in the range of about 400 to 600 micronsThe mesh of gas holes of the material helps to perform the manifold function, but other materials may be used. Under certain conditions, have a ratio of GranufoamMaterials of high or low density (smaller pore size) may be desirable. The manifold member 114 may also be a reticulated foam that is subsequently felted to a thickness of about 1/3 a of the original thickness of the manifold material. Among the many possible materials, the following may be used: granufoamMaterials or Foamex industrial foam (www.foamex.com). In some cases, it may be desirable to add ionic silver to the foam in a micro-bonding process or to add other substances, such as antimicrobial agents, to the manifold member. The manifold member 114 may be a bioabsorbable material or a bio-inert material (bio-inert material) or an anisotropic material.

The sealing subsystem 116 includes an over-drape 118 or drape. An over-drape 118 covers the manifold member 114 and extends beyond a peripheral edge 121 of the manifold member 114 to form a drape extension 120. The drape extension 120 may be sealed against the patient's epidermis 108 by a sealing device 122, such as a pressure sensitive adhesive 124. The sealing device 122 may take many forms, such as an adhesive sealing tape or drape tape or strip; double-sided drape tape; an adhesive 124; pasting; a hydrocolloid; a hydrogel; or other sealing means. If a tape is used, the tape may be formed of the same material as the over-drape 118 and have a pre-applied pressure sensitive adhesive. The pressure sensitive adhesive 124 may be applied on the second, patient-facing side of the drape extension 120. The pressure sensitive adhesive 124 provides a substantially fluid tight seal between the over-drape 118 and the patient's epidermis 108. By "fluid seal" or "seal" is meant a seal sufficient to maintain reduced pressure at a desired location for the particular reduced-pressure subsystem involved. The pressure sensitive adhesive 124 may have a removable strip covering the adhesive 124 before the over-drape 118 is secured to the patient.

The over-drape 118 may be an elastomeric material that provides a fluid seal. The sealing member may for example be an impermeable or semi-permeable elastomeric material. "elastomer" means a polymeric material having elastomeric properties and generally rubber-like properties. More specifically, most elastomers have an elongation greater than 100% and a considerable resilience. The resiliency of a material refers to the ability of the material to recover from elastic deformation. Examples of elastomers may include, but are not limited to: natural rubber, polyisoprene, styrene-butadiene rubber, chloroprene rubber, polybutadiene, nitrile rubber, butyl rubber, ethylene-propylene-diene monomer, chlorosulfonated polyethylene, polysulfide rubber, polyurethane, EVA film, copolyester, and silicone resin. Specific examples of the sealing member material include silicone drape, 3m tegasermDrapes, acrylic drapes such as the acrylic drape available from Avery Dennison or incise drape (incise drape).

The reduced-pressure subsystem 126 includes a reduced-pressure source 128, and the reduced-pressure source 128 may take many different forms. The reduced-pressure source 128 provides reduced pressure as part of the reduced-pressure treatment system 100. The reduced-pressure source 128 may be any device for supplying reduced pressure, such as a vacuum pump, wall suction, or other source. While the amount and nature of reduced pressure applied to the tissue site will generally vary depending on the application, the reduced pressure will generally be between-5 mm Hg to-500 mm Hg and more typically between-100 mm Hg to-300 mm Hg.

As used herein, "reduced pressure" generally refers to a pressure that is less than the ambient pressure at the tissue site 106 being subjected to treatment. In most cases, this reduced pressure will be less than the atmospheric pressure at which the patient is located. Alternatively, the reduced pressure may be less than the hydrostatic pressure at the tissue site. The reduced pressure may initially generate fluid flow in the manifold member 114, in the reduced-pressure conduit 148, and adjacent to the tissue site 106. As the hydrostatic pressure around the tissue site 106 approaches the desired reduced pressure, the flow may drop and the reduced pressure may be maintained. Unless otherwise indicated, the values of pressure specified herein are gauge pressures. The reduced pressure delivered may be constant or variable (patterned or random) and may be delivered continuously or intermittently. Although the terms "vacuum" and "negative pressure" may be used to describe the pressure applied to the tissue site, the actual pressure applied to the tissue site may be greater than the pressure typically associated with a complete vacuum. Consistent with the use herein, an increase in reduced or vacuum pressure generally refers to a relative decrease in absolute pressure.

In the illustrative embodiment of fig. 1, the reduced-pressure source 128 is shown as having a reservoir region 131 or canister region with a window 138 that provides a visual indication of the level of fluid within the reservoir 150. An interposed membrane filter, such as a hydrophobic or oleophobic filter, may be disposed between the reduced-pressure delivery conduit or pipe 148 and the reduced-pressure source 128.

The reduced pressure source 128 has a display 130. the display 130 may include a warning light or information indicator 132, a battery light or indicator 134, a reservoir full/occlusion 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 keyboard may also be provided for entering desired pressure or other information. As described further below, the reduced-pressure subsystem 126 includes a reduced-pressure control unit similar to the reduced-pressure control unit 260 in fig. 2A.

The reduced pressure generated by the reduced-pressure source 128 is communicated to the reduced-pressure interface 144 through a reduced-pressure delivery conduit 148, and the reduced-pressure interface 144 may be an elbow-shaped orifice 146. In one illustrative embodiment, the orifice 146 is a TRAC available from Kinetic Concepts Inc. of san Antonio, TexasProcess port (technology port). The reduced-pressure interface 144 allows reduced pressure to be communicated to the sealing subsystem 116 and to be achieved within interior portions of the sealing subsystem 116. In the present illustrative embodiment, the elbow aperture 146 extends through the over-drape 118 and into the manifold member 114.

In operation, the reduced pressure treatment system 100 is applied to treat a tissue site 106, such as a wound 104, by: the manifold member 114 is placed adjacent the wound 104, a fluid seal is provided over the manifold member 114 and a portion of the epidermis 108 by using the sealing subsystem 116, the reduced-pressure subsystem 126 is attached and the reduced-pressure subsystem 126 is activated. The reduced-pressure subsystem 126 delivers reduced pressure to the manifold member 114, which the manifold member 114 distributes the reduced pressure to the wound site 106 and potentially provides other beneficial effects, such as a closing force when using a closing dressing bolster in certain applications. The reduced-pressure subsystem 126 may be used for wound applications as shown, and the reduced-pressure subsystem 126 may also be used for percutaneous applications, such as applying reduced pressure to bone, tissue, or other wound sites. When 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. The status of the reservoir 150 may be visually monitored through the window 138 because it is desirable to minimize any interruption in treatment, but it is desirable to have the reduced-pressure subsystem 126 automatically alert the patient when the reservoir 150 is full or when a blockage has occurred such that reduced pressure is no longer being delivered. It may also be desirable to shut down the reduced pressure source 128 when the reservoir 150 is full or plugged.

Referring now primarily to fig. 2A, an illustrative embodiment of a reduced-pressure system 200 that may be used as the reduced-pressure subsystem 126 of the reduced-pressure treatment system 100 in fig. 1 is shown. The reduced pressure is provided by the reduced-pressure system 200 and ultimately delivered to a delivery site, such as the reduced-pressure interface 144 and the tissue site 106 of fig. 1, by a reduced-pressure delivery conduit 222 that is used for medical purposes. The reduced-pressure system 200 includes a reservoir 224 formed with a reservoir housing 226 defining an interior space 230. The reservoir 224 may be any unit for containing a fluid, such as a canister, a bag, an impermeable enclosure, and the like. Adjacent the top portion 228 (for the orientation shown when the unit is standing parallel to the gravity field), a number of apertures may be formed through the reservoir housing 226. For example, a delivery conduit aperture 232, a source aperture 234, and a sensor aperture 240 may be formed through the reservoir housing 226. The reduced-pressure delivery conduit 222 is connected with a reduced-pressure delivery conduit aperture 232 such that the reduced-pressure delivery conduit 222 may be placed in fluid communication or fluidly coupled with the interior space 230. A source conduit 236 is connected to the source aperture 234 to allow the source conduit to be in fluid communication or fluidly coupled with the interior space 230. Similarly, a pressure sensor conduit 242 is connected with the sensor port 240 to allow the pressure sensor conduit 242 to be placed in fluid communication or fluidly coupled with the interior space 230. Although the sensor aperture 240 is shown slightly below the source aperture 234, it should be noted that in other embodiments, these apertures 234, 240 may be on the same vertical level.

The reduced-pressure delivery conduit 222 delivers reduced pressure for medical purposes and receives fluid, such as exudate, into the interior space 230. Many filters, such as hydrophobic filters or odor filters, may be desired on the conduits 222, 236, and 242. For example, the source conduit 236 is shown with a first filter element 238, and the pressure sensor conduit 242 is shown with a second filter element 244. Although the filter units 238 and 244 are shown as single units, it should be understood that multiple filters may make up each filter unit.

The pressure sensor conduit 242 provides fluid communication from the interior space 230 to the pressure sensor 246. The pressure sensor 246 may be any device capable of sensing the pressure in the pressure sensor conduit 242 and generating a response signal, which may be analog or digital, and transmitting the signal to the reduced pressure control unit 260 via the communication conduit 247. In alternative embodiments, the pressure sensor 246 may be or include a pneumatic regulator coupled to a reduced pressure source, such as a vacuum pump 248, a regulated wall suction, a mechanical device, or other pressure reduction device.

The source conduit 236 is in fluid communication with the interior space 230 and is also in fluid communication with a reduced pressure source, such as a vacuum pump 248. Vacuum pump 248 operates to generate a reduced pressure that is introduced into source conduit 236. In the present illustrative embodiment, the vacuum pump 248 is powered by electricity, as represented by a first power line 252. The first power line 252 is electrically coupled to a pump power supply (pump power supply) 250. The pump power supply 250 may be a battery power source or regulated power from another source. A portion of the first power line 252 may include a power sensor 254 and a current control unit 256. Power sensor 254 may be any device for determining the amount of power being supplied to vacuum pump 248. For example, the power sensor 254 may be a current sensor operable to generate a current signal or supply data signal (supply data signal) I. More generally, a supply data signal may be generated that provides information regarding the rate of delivery or attempted delivery of reduced pressure. In an illustrative embodiment, the supply data signal may be the current supplied to the vacuum pump. In another illustrative embodiment, the supply data signal may be a signal indicative of a valve opening on a regulated wall inhaler unit. Whether the current signal, other power data, or supply data is generated by the power sensor 254 or other sensor that measures a signal related to the supply rate, the resulting signal I is communicated to the reduced-pressure control unit 260 by the communication conduit 255.

The reduced-pressure control unit 260 contains circuitry or a microprocessor that controls functions within the reduced-pressure system 200. The reduced pressure control unit 260 receives a pressure signal P from a communication conduit 247 and supply data, such as a signal I, from a communication conduit 255 coupled to a sensor, such as a power sensor 254. The reduced-pressure control unit 260 determines whether the interior space 230 of the reservoir 224 is substantially full or whether the conduits 222, 236, 242 are blocked. If the reduced-pressure control unit 260 determines that the interior space 230 is full or the conduit is blocked, the reduced-pressure control unit 260 may send an alert to the speaker 216 and provide an alarm signal to the display unit 204. The reduced-pressure control unit 260 may also generate a pump control signal PC that is communicated by the communication conduit 261 to the current control unit 256 and may be used to increase power to the vacuum pump 248 or slow or stop the vacuum pump 248. Similarly, if a different reduced pressure source is used, the control signal may be used to adjust the reduced pressure source. In alternative embodiments, it may be desirable to provide other inputs or data to the reduced-pressure control unit 260, such as temperature inputs that may be used to predict the viscosity of the fluid captured within the interior space 230, and to further adjust parameters used to determine when the reservoir is full, such as the time interval used.

Referring now primarily to fig. 2A, 2B, 2C, in operation, the reduced-pressure system 200 is initially activated and has unplugged conduits 222, 236, 242 and an empty interior space 230. The reduced pressure is delivered to the interior space 230 and delivered to the reduced-pressure delivery conduit 222 and to the desired location. Fig. 2A shows such an initial state with empty reservoir 224. When reduced pressure is delivered to treat a tissue site, such as a wound, on a patient, various fluids are generally received through the reduced pressure delivery conduit 222 and are delivered into the interior space 230 where the fluids collect. Fig. 2B shows the fluid 258 collecting in the bottom portion of the interior space 230. The reduced pressure control unit 260 continuously operates the vacuum pump 248 and the pressure sensor 246 continuously monitors the pressure experienced within the pressure sensor conduit 242, which generally 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 greater than a threshold value. However, when the fluid 258 fills or substantially fills the interior space 230 such that the sensor orifice 240 is covered by the fluid 258, the incompressible nature of the fluid 258 will cause the pressure sensor 246 in fluid communication with the interior space 230 to experience a reduction in reduced pressure (an increase in absolute pressure). The remaining void space 259 is shown.

In an illustrative embodiment, if the reduced-pressure control unit 260 determines that the desired reduced pressure within the interior space 230 is below the desired reduced-pressure level despite the increased power or the elapse of the wait time, the reduced-pressure control unit 260 will send an alarm signal to the current control unit 256 or a pump control signal to shut down the vacuum pump 248. If the reduced-pressure control unit 260 is unable to increase the reduced pressure (below absolute pressure) within the interior space 230 due to a blockage in one of the conduits 222, 236, 242, the reduced-pressure control unit 260 may shut down or send an alarm. Additional embodiments of the manner in which the reduced-pressure control unit 260 may operate are provided in connection with fig. 3 and 4.

Referring now primarily to fig. 3, a schematic diagram illustrating operating parameters with respect to pressure and power that may be used by the reduced-pressure control unit 260 in the reduced-pressure system 200 in fig. 2A-2C is shown. In the present illustrative embodiment, the motive force is represented by electric current. The diagram has a horizontal axis 302 and a vertical axis 304. Horizontal axis 302 shows a relative measure of the power provided to vacuum pump 248 in reduced-pressure system 200. Longitudinal axis 304 represents the pressure measured by pressure sensor 246 and generally corresponding to the reduced pressure delivered into interior space 230 of reservoir 224.

Referring to fig. 2A and 3, prior to activation of the depressurization system 200, the depressurization system 200 may be represented on the graph of fig. 3 at a first point 306-no depressurization (gauge pressure) and no power. Once activated, the vacuum pump 248 runs until the reduced pressure exceeds the selected level a and is then turned off. The selected level a may be preset or may be input by the user or care provider. Thus, before the vacuum pump 248 is temporarily stopped, the reduced pressure may be represented by a second point 308. The second point 308 shows that the reduced pressure has now exceeded the threshold selected level a and that the vacuum pump 248 is currently operating due to a positive current measurement on the horizontal axis. At this time, the reduced-pressure control unit 260 may cause the vacuum pump 248 to turn off, for example, by sending a pump control signal PC to the current control unit 256. Vacuum pump 248 may remain off until pressure sensor 246 determines that the reduced pressure has decreased to a level below threshold level a or some other setting. At this point, the vacuum pump 248 will be reactivated to again restore the pressure, measured by the pressure sensor 244, generally equivalent to the pressure within the interior space 230, to again exceed level a.

In one illustrative embodiment, if the source conduit 236 begins to experience a partial blockage, the previously used level of reduced pressure supplied by the vacuum pump 248 may not be able to cause the reduced pressure in the interior space 230 (as measured by the pressure sensor 244 in the pressure sensor conduit 242) to exceed the threshold level a. The power level of the vacuum pump 248 may first be increased by the reduced-pressure control unit 260 for a period of time before concluding that the reservoir or canister 224 is full and turning off. The power level of the vacuum pump may be increased up to the full power level or a selected level, as shown by reference line B on the graph. Thus, in one embodiment, the reduced pressure control unit 260 may determine that the pressure at the pressure sensor 246 is below the pressure level a and that the reduced pressure is not increasing. Full or maximum power setting B may then be applied to vacuum pump 248 such that reduced-pressure system 200 may be represented on the figure by third point 310. If partial blockage is the primary problem that renders it impossible to maintain the pressure in full response, the vacuum pump 248 at the increased full power level can move to a fourth point 312 that exceeds the pressure threshold level A, and the vacuum pump 248 will shut down until the pressure again drops below level A. If the blockage of the source conduit 236 causes even full power not to move the pressure beyond level a after a given time, then an alarm is signaled and the vacuum pump 248 is turned off. Note that as shown in fig. 2C, when incompressible fluid 258 covers sensor orifice 240, the increased power to vacuum pump 248 will result in a decrease in pressure in the remaining void space 259 of reservoir 224, but will not increase the reduced pressure and therefore will not cause the pressure measured by pressure sensor 246 to exceed level a. Thus, the system 100, and in particular the vacuum pump 248, will shut down and give a full reservoir/occlusion indication.

Referring now primarily to fig. 4, an illustrative embodiment of a reduced pressure control unit 460 is shown. The reduced-pressure control unit 460 includes a housing unit 462, the housing unit 462 housing various components for controlling a reduced-pressure system, such as the system 200 of fig. 2A-2C. The reduced-pressure control unit 460 may receive many different input signals from the input device. The reduced-pressure control unit 460 is shown as having a first input 464, the first input 464 being in this illustration a pressure signal P representative of the pressure within the interior space of the reservoir as measured by the pressure sensor in the pressure sensor conduit. If the pressure signal supplied to the first input 464 has not been digitized, a first analog-to-digital converter 466 may be included to receive and convert the pressure signal to a digital signal. A second input 468 may be included. In this illustration, the second input 468 is a supply signal, such as a signal representing power data to the pump, and may be, inter alia, signal I. As previously mentioned, if the supply signal I is not already in digitized form, a second analog-to-digital converter 470 may be included to convert the signal to digital form.

Similarly, a third input signal 472 is shown and is only 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 reflecting the temperature within the fluid in the reservoir. The fluid temperature may affect the viscosity of the fluid and, in turn, may affect parameters such as the interval for waiting for a response within the reduced pressure system. If the representative third input signal 472 is not already in digitized form, another analog-to-digital converter 474 may be included.

The signals received (and converted, if required) in the input signals 464, 468, 472 may be transferred to a buffer memory 476 and supplied to a memory unit 478 or directly transferred to a microprocessor 482. It may be desirable to keep a record of the input data to allow different determinations, such as whether the pressure is increasing or decreasing. The memory unit 478 may also be used to determine whether a pressure change has not been experienced for an extended period of time when the reduced-pressure source has been turned off. In such a case, it may be desirable for the reduced pressure control unit 460 to provide a warning light that the reduced pressure delivery conduit, such as the reduced pressure delivery conduit 222 of fig. 2A, may be blocked.

The microprocessor 482 is operable to make a number of different decisions, for example decisions regarding when the vacuum pump should be powered up, shut down, or when an alarm signal or other signal should be generated, as will be explained in connection with fig. 5. The microprocessor 482 has a number of outputs. The first output 484 is a pump control signal that may be transmitted to control a vacuum pump. For example, the pump control signal 484 may be transmitted to the current control unit 256 in fig. 2A to adjust the power to the vacuum pump 248 or to shut down the vacuum pump 248. In embodiments with other reduced pressure sources, the control signal may be used to adjust the supply rate. The microprocessor 482 may also provide a second output 486, which second output 486 may be an alarm signal. The alarm signal may activate an audible alarm, such as speaker 142 in the figure. The third output 488 is a representative output signal that may control other features, such as status lights provided on a display, such as lights or indicators 132 or 136 in fig. 1. The power supply 490 supplies power to various components within the reduced-pressure control unit 460 and may be a battery or may be regulated power from another source.

For control units that utilize a microprocessor, such as the reduced-pressure control unit 460 of fig. 4, the microprocessor, such as microprocessor 482, may be designed for use with a memory device, such as buffer memory 476 or memory unit 478, to perform a number of different operations in using the input signals 464, 468 and generating the appropriate output signals, such as signals 484, 486, 488.

Referring now primarily to FIG. 5, one illustrative representation of possible logic or operations that may be used in the control unit is shown. Operation begins at step 502 and proceeds to decision step 504, where the following question is asked at decision step 504: is the reduced pressure from the pressure sensor in the pressure sensor conduit greater than the threshold value? (the reduced pressure in the pressure sensor conduit is typically the same as in a reservoir fluidly coupled to the pressure sensor conduit). In other words, is the absolute value of the negative gauge pressure greater than the threshold value? Referring to fig. 3, the question being asked is whether the pressure point is below the threshold line a. If the answer is in the affirmative, then an increase in reduced pressure is not necessary and the system may wait. Thus, flow proceeds to step 506 where the system waits for a certain time interval before returning again to decision step 504 at step 506. The time interval and others may be pre-programmed or may be entered by the care provider or user.

If the response to decision step 504 is negative, then additional reduced pressure is desired and the vacuum pump is activated at step 508. Then, before the system proceeds to decision step 512, the vacuum pump or reduced pressure source is allowed to act for a time interval at step 510, and the following questions are asked at decision step 512: is the reduced pressure increasing? In other words, the absolute value of the reduced pressure in the reservoir is increasing-a greater number? If so, the system proceeds to decision step 514, where decision step 514 again asks whether the reduced pressure is greater than the threshold. If the answer is in the affirmative, then the system proceeds to step 516 and the pump or reduced pressure source is turned off. In this case, the system will upgrade the signal indicating no jam/underfill in step 518 and will return along path 520 to decision step 504.

If the response to decision step 514 is negative, the system may wait a specified time interval at step 522 before returning again to decision step 512. This forms a loop and the loop may continue until a threshold is reached or until the reduced pressure no longer increases. Once the pressure is no longer increasing, the answer at decision step 512 is negative and the system proceeds to decision step 524. Decision step 524 asks whether the pump is full power (or the reduced pressure source is at maximum reduced pressure). If the answer is negative, then power to the pump is increased at step 526, and if yes, then a timer is started at step 528. Then, decision step 530 is reached, and decision step 530 asks the following question: is the reduced pressure increasing? If the answer is in the affirmative, then the analysis continues along path 532 to decision step 514. If the answer is negative, then the process continues to decision step 534. Decision step 534 asks a question whether the timer started at 528 has reached the maximum count value. If the timer has not reached the maximum count value, then additional time is consumed at step 536. If the timer has reached the maximum count value, then the process has timed out and the process proceeds to step 538 where a signal is sent indicating that the reservoir (tank) is full/jammed at step 538. In addition, an alarm signal may be sent at step 540. The vacuum pump or reduced pressure source may then be turned off at step 542. The process ends at step 544. It will be appreciated that the reservoir (canister) full/occlusion signal is given when the reservoir is considered full or when an occlusion exists. Either way, the system is unable to restore pressure in the reservoir and a reservoir full/blocked condition exists. This logic is only one of many ways that the control unit can be programmed.

Although the present invention and its advantages have been disclosed in the context of certain illustrative, non-limiting embodiments, it should be understood that various changes, substitutions, permutations and alterations can be made herein without departing from the scope of the invention as defined by the appended claims. It will be appreciated that features described in connection with any one embodiment may also be applicable to any other embodiment.

Claims (21)

1. A reduced-pressure treatment system for treating a tissue site on a patient, the system comprising:

a manifold member for placement adjacent the tissue site;

an over-drape for providing a fluid seal over the manifold member and patient;

a reduced-pressure subsystem for delivering a reduced pressure to the over-drape; and is

Wherein the reduced-pressure subsystem comprises:

a reservoir having an interior space operable to contain a fluid,

a reduced-pressure delivery conduit in fluid communication with the interior space for delivering a 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 operable to deliver reduced pressure to the source conduit, an

A reduced-pressure control unit associated with the pressure sensor and the 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 determine when a reservoir full/blocked condition exists.

2. The system for treating a tissue site on a patient according to claim 1, wherein the reduced-pressure control unit is further operable to turn off the reduced-pressure source when a reservoir full/blocked condition exists.

3. The system for treating a tissue site on a patient according to claim 1, wherein the reduced pressure control unit is further operable to turn off the reduced pressure source and send an alarm signal when a reservoir full/blocked condition exists.

4. The system for treating a tissue site on a patient according to claim 1, wherein the reduced-pressure control unit is further operable to send an alarm signal when a reservoir full/blocked condition exists.

5. The system for treating a tissue site on a patient according to claim 1, wherein the pressure sensor conduit is placed in fluid communication with the reservoir adjacent the top portion for a direction parallel to gravity.

6. The system for treating a tissue site on a patient according to claim 1, wherein the reduced-pressure source is a vacuum pump.

7. The system for treating a tissue site on a patient according to claim 1, wherein the reduced-pressure source is a vacuum pump, wherein the reduced-pressure control unit is further operable to shut off the vacuum pump and send an alarm signal when a reservoir full/blocked condition exists.

8. The system for treating a tissue site on a patient according to claim 1, wherein the reduced pressure source is a regulated wall inhaler.

9. A reduced-pressure system for providing reduced pressure and for receiving a fluid, the reduced-pressure system comprising:

a reservoir having an interior space operable to contain a fluid;

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;

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 operable to deliver reduced pressure to the source conduit; and

a reduced-pressure control unit associated with the pressure sensor and the 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 determine when a reservoir full/blocked condition exists.

10. A reduced-pressure system for supplying reduced pressure for medical applications and receiving fluids, the system comprising:

a reservoir housing forming an interior space;

a reduced-pressure source for delivering a 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;

a supply conduit fluidly coupled to the interior space;

a supply sensor for measuring a supply rate of reduced pressure delivered by the reduced-pressure source and operable to generate a signal I indicating that reduced pressure may be used by 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 generate a signal P indicative of a pressure level in the pressure sensor conduit adjacent the pressure sensor; and

a reduced-pressure control unit coupled to the supply sensor, the pressure sensor, and the reduced-pressure source, the reduced-pressure control unit operable to receive a signal I from the supply sensor and a signal P from the pressure sensor, and operable to adjust the control signal to cause the reduced-pressure source to provide a desired pressure to the reservoir and to cause the reduced-pressure source to shut off when the reservoir is full.

11. The reduced-pressure system according to claim 10, wherein the reduced-pressure control unit includes:

a microprocessor;

a memory device associated with the microprocessor;

a plurality of input devices associated with the microprocessor, the input devices for receiving and transmitting signals P and I in usable form to the microprocessor;

an output device associated with the microprocessor, the output device for receiving the control signal from the microprocessor and making the control signal available for delivery to the reduced pressure source; and is

Wherein the microprocessor and the memory device are operable to determine whether the absolute value of the pressure value represented by signal P is greater than a selected pressure value and, if not, to activate the reduced pressure source, and are further operable to use the control signal to deactivate the reduced pressure source and to send a reservoir full/occlusion signal if the reduced pressure source is unable to increase the absolute value of the pressure value represented by signal P for more than a preset time interval.

12. The reduced-pressure system of claim 10, wherein the pressure sensor conduit is placed in fluid communication with the reservoir, adjacent the top portion, for a direction parallel to gravity.

13. The reduced-pressure system of claim 10, wherein the pressure sensor conduit is placed in fluid communication with the reservoir adjacent a top portion for a direction parallel to gravity, and the reduced-pressure source is placed in fluid communication with the reservoir adjacent the top portion.

14. The reduced-pressure system according to claim 10, wherein the reduced-pressure control unit includes:

a microprocessor;

a memory device associated with the microprocessor;

a plurality of input devices associated with the microprocessor, the input devices for receiving and transmitting signals P and I in usable form to the microprocessor;

an output device associated with the microprocessor for receiving the control signal from the microprocessor and making the control signal available to control the vacuum pump; and is

Wherein the microprocessor and the memory device are operable to determine whether the absolute value of the pressure value represented by signal P is greater than a selected pressure value and, if not, to activate the pump, and are further operable to deactivate the reduced pressure source and send a reservoir full/occlusion signal when the reduced pressure source is unable to increase the absolute value of the pressure value for a time interval greater than a set value and after increasing the delivery of reduced pressure from the reduced pressure source to a set value.

15. A method of detecting a fill state of a reservoir used to treat 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 treatment system;

applying reduced pressure to the 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 reservoir and a supply conduit in fluid communication with the reservoir, and wherein the step of monitoring the pressure within the reservoir comprises monitoring the pressure within the pressure sensor conduit; and

terminating the application of reduced pressure when the pressure in the pressure sensor conduit drops below the selected absolute value for a specified time interval.

16. The method of claim 15, wherein the reduced-pressure source is a vacuum pump.

17. The method of claim 15, wherein the reduced-pressure source is a vacuum pump, and wherein the step of terminating the application of reduced pressure comprises the steps of: terminating therapy when the monitored pressure within the pressure sensor conduit falls below the selected absolute value for a specified time interval and the increased power to the vacuum pump does not raise the monitored pressure in absolute value.

18. A method of manufacturing a reduced-pressure system, the method comprising:

forming a reservoir having an interior space operable to contain a fluid;

fluidly coupling a reduced-pressure delivery conduit to the interior space, the reduced-pressure delivery conduit for delivering 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;

providing a reduced pressure source responsive to a control signal;

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 determine when a reservoir full/plugged condition exists; and

associating the reduced pressure control unit with the pressure sensor and the reduced pressure source.

19. The method of manufacturing a reduced-pressure system according to claim 18, wherein the step of providing a reduced-pressure control unit further comprises providing a control unit comprising:

a microprocessor;

a memory device associated with the microprocessor;

a plurality of input devices associated with the microprocessor, the input devices for receiving and transmitting signals P and I in usable form to the microprocessor;

an output device associated with the microprocessor, the output device to receive the control signal from the microprocessor and make the control signal available to control the reduced-pressure source; and is

Wherein the microprocessor and memory device are operable to determine whether the absolute value of the pressure value (represented by signal P) is greater than a selected pressure value and, if not, to activate the reduced pressure source, and are further operable to use the control signal to deactivate the reduced pressure source and to send a reservoir full/occlusion signal if the reduced pressure source is unable to increase the absolute value of the pressure value represented by signal P for more than a set time interval.

20. The method of manufacturing a reduced-pressure system according to claim 19, wherein the step of coupling a pressure sensor conduit comprises the steps of: the pressure sensor conduit is coupled to the reservoir adjacent the top portion for a direction parallel to gravity.

21. The method of manufacturing a reduced-pressure system according to claim 19, wherein the step of coupling a pressure sensor to the pressure sensor conduit comprises the steps of: coupling the pressure sensor conduit to the reservoir adjacent a top portion for a direction parallel to gravity, and wherein coupling a source conduit to the interior space comprises: coupling the source conduit to the reservoir adjacent the top portion of the reservoir.