WO2022118118A1

WO2022118118A1 - Negative-pressure wound therapy dressing with wireless power transmission to integral pump

Info

Publication number: WO2022118118A1
Application number: PCT/IB2021/060448
Authority: WO
Inventors: Christopher Brian Locke
Original assignee: Kci Manufacturing Unlimited Company
Priority date: 2020-12-03
Filing date: 2021-11-11
Publication date: 2022-06-09

Abstract

Disclosed embodiments may relate to a dressing, such as an absorptive dressing, within a negative-pressure therapy system. In some embodiments, the dressing may have an integral pump, for example located within the dressing, which may be configured to provide negative pressure within the dressing. In some embodiments, the pump may be wirelessly powered, for example using a separate, external power source and/or controller. For example, when the negative pressure in the dressing falls below a pre-set threshold, power may be wirelessly transmitted from the external power source to the integral pump within the dressing. Additionally disclosed are other apparatus, dressings, systems, and methods.

Description

NEGATIVE-PRESSURE WOUND THERAPY DRESSING WITH WIRELESS

POWER TRANSMISSION TO INTEGRAL PUMP

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority to U.S. Provisional Application No. 63/121,015, filed on December 3, 2020, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] The invention set forth in the appended claims relates generally to tissue treatment systems and more particularly, but without limitation, to systems, dressings, and related apparatuses for providing negative-pressure therapy to a tissue site.

BACKGROUND

[0003] Clinical studies and practice have shown that reducing pressure in proximity to a tissue site can augment and accelerate growth of new tissue at the tissue site. The applications of this phenomenon are numerous, but it has proven particularly advantageous for treating wounds . Regardless of the etiology of a wound, whether trauma, surgery, or another cause, proper care of the wound is important to the outcome . Treatment of wounds or other tissue with reduced pressure may be commonly referred to as "negative-pressure therapy," but is also known by other names, including "negativepressure wound therapy," "reduced-pressure therapy," "vacuum therapy," "vacuum-assisted closure," and "topical negative-pressure," for example. Negative-pressure therapy may provide a number of benefits, including migration of epithelial and subcutaneous tissues, improved blood flow, and microdeformation of tissue at a wound site. Together, these benefits can increase development of granulation tissue and reduce healing times.

[0004] There is also widespread acceptance that cleansing a tissue site can be highly beneficial for new tissue growth. For example, a wound or a cavity can be washed out with a liquid solution for therapeutic purposes. These practices are commonly referred to as "irrigation" and "lavage" respectively. "Instillation" is another practice that generally refers to a process of slowly introducing fluid to a tissue site and leaving the fluid for a prescribed period of time before removing the fluid. For example, instillation of topical treatment solutions over a wound bed can be combined with negativepressure therapy to further promote wound healing by loosening soluble contaminants in a wound bed and removing infectious material. As a result, soluble bacterial burden can be decreased, contaminants removed, and the wound cleansed.

[0005] While the clinical benefits of negative-pressure therapy and/or instillation therapy are widely known, improvements to therapy systems, components, and processes may benefit healthcare providers and patients. BRIEF SUMMARY

[0006] New and useful systems, apparatuses, and methods for tissue treatment in a negativepressure therapy environment are set forth in the appended claims. Illustrative embodiments are also provided to enable a person skilled in the art to make and use the claimed subject matter.

[0007] For example, some embodiments may relate to a dressing, such as an absorptive dressing, within a negative-pressure therapy system. In some embodiments, the dressing may have an integral pump, for example located within the dressing, which may be configured to provide negative pressure within the dressing. In some embodiments, the pump may be wirelessly powered, for example using a separate, external power source and/or controller. For example, when the negative pressure in the dressing falls below a pre-set threshold, power may be wirelessly transmitted from the external power source to the integral pump within the dressing. Some embodiments may relate to a system for providing negative pressure wound therapy, for example using such a dressing with integral pump. In some embodiments, the system may comprise the dressing with a pump, a power source, and a wireless power transmission device configured to wirelessly couple the power source to the pump. Some embodiments may further comprise a pump actuator configured to activate the pump whenever negative pressure in the absorptive dressing drops below a pre-set threshold, such as the therapeutic negative pressure level. In some embodiments, the wireless power transmission device may comprise two portions, a first portion located external to the absorptive dressing and a second portion located within the absorptive dressing; wherein the first portion may be configured to transmit power wirelessly to the second portion. For example, the wireless power transmission device may utilize inductive power transmission, and the first portion may comprise a transmitter coil, while the second portion may comprise a receiver coil.

[0008] More generally, some embodiments may relate to a system for providing negativepressure wound therapy, which may comprise : an absorptive dressing; a pump attached to the absorptive dressing, fluidly coupled to the absorptive dressing, and configured to provide negative pressure to the absorptive dressing; a power source isolated from the pump; and a wireless power transmission device configured to wirelessly couple the power source to the pump. Some embodiments may further comprise a pump actuator configured to activate the pump, for example by electrically coupling the pump to the wireless power transmission device, whenever negative pressure in the absorptive dressing drops below a pre-set threshold. In some embodiments, the pump actuator may comprises a pressure switch configured to activate the pump when the negative pressure in the absorptive dressing is less than the pre-set threshold, and to deactivate the pump when the negative pressure meets the pre-set threshold. The pump, in some embodiments, may be disposed within the absorptive dressing. In some embodiments, the absorptive dressing may comprise: a manifold, an absorbent layer, and a cover; the cover may be configured to substantially prevent fluid flow therethrough and to be disposed over the manifold, the absorptive layer, and the pump; and the cover may further comprise a vent configured to fluidly couple the pump to an external environment through the cover. Some embodiments may further comprise a filter configured to prevent liquid from entering the pump, while allowing communication of negative pressure from the pump to the absorptive dressing. In some embodiments, the wireless power transmission device may comprise two portions, a first portion located external to the absorptive dressing and a second portion located within the absorptive dressing; wherein the first portion may be configured to transmit power wirelessly to the second portion. The first portion may be electrically coupled to the power source, in some embodiments, and the second portion may be electrically coupled to the pump. In some embodiments, the wireless power transmission device may comprise a primary coil and a secondary coil (e.g. with the primary coil forming the first portion of the wireless power transmission device, and the secondary coil forming the second portion of the wireless power transmission device), wherein the primary coil may be configured to induce power in the secondary coil upon receiving power from the power source.

[0009] Some embodiments may further comprise a processor configured to operate the power source. In some embodiments the processor may be configured to intermittently power the primary coil. For example, the processor may be configured to power the primary coil only when the negative pressure in the absorbent dressing is below a pre-set, therapeutic-level threshold; the processor may be configured to determine when negative pressure is below the threshold by polling current drain at the primary coil; the processor may be configured to periodically poll the primary coil to check current draw to determine if pressure is being held; and/or the processor may be configured to power the primary coil based on current drain at the primary coil. In some embodiments, the processor may be configured to maintain power to the primary coil until the negative pressure threshold has been met and/or the processor may be configured to determine if the negative pressure threshold has been met based on current dram at the primary coil. In some embodiments, the controller may be configured to permanently and/or continuously power the primary coil. For example, some such configurations may not require a controller, but rather may be configured so that the power source directly and/or continuously powers the primary induction coil when the system is in use. For example, the primary coil may be continuously powered, and the pump actuator may control power to the pump.

[0010] Other example embodiments may relate to an apparatus for providing negativepressure wound therapy, which may comprise : an absorptive dressing; a pump attached to the absorptive dressing and configured to provide negative pressure to the absorptive dressing; and a receiver portion of a wireless power transmission device, configured to wirelessly receive power from an external source and direct the power to the pump . Some embodiments may further comprise a pump actuator configured to activate the pump whenever negative pressure drops below a pre-set threshold. In some embodiments, the receiver portion may comprise a receiver loop of a two-part inductive power system.

[0011] A method, for providing negative-pressure wound therapy to a tissue site, is also described herein, wherein some example embodiments may include: applying an absorptive negativepressure dressing with an integral pump to the tissue site; and wirelessly providing power to the pump. In some embodiments, wirelessly providing power to the pump may comprise intermittently energizing the pump. In some embodiments, wirelessly providing power may further comprise aligning a transmitter coil and a receiver coil of an inductive power coupling system and inducing power in the receiver coil by energizing the transmitter coil. Some embodiments may further comprise monitoring alignment of the coils and activating an alarm when the coils are not aligned. Some embodiments may further comprise electrically coupling the receiver coil to the pump whenever negative pressure in the absorptive dressing falls below a pre-set threshold, and electrically uncoupling the receiver coil from the pump whenever the negative pressure in the absorptive dressing meets the pre-set threshold. In some embodiments, wirelessly providing power may further comprise continuously energizing the transmitter coil. In some embodiments, wirelessly providing power may further comprise energizing the transmitter coil when the negative pressure in the absorptive dressing falls below a pre-set threshold.

[0012] Objectives, advantages, and a preferred mode of making and using the claimed subject matter may be understood best by reference to the accompanying drawings in conjunction with the following detailed description of illustrative embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a block diagram of an example embodiment of a therapy system that can provide negative-pressure treatment and instillation treatment in accordance with this specification;

[0014] Figure 2 is a graph illustrating additional details of example pressure control modes that may be associated with some embodiments of the therapy system of Figure 1;

[0015] Figure 3 is a graph illustrating additional details that may be associated with another example pressure control mode in some embodiments of the therapy system of Figure 1 ;

[0016] Figure 4 is a chart illustrating details that may be associated with an example method of operating the therapy system of Figure 1;

[0017] Figure 5 is a schematic diagram illustrating an example of the therapy system of Figure i;

[0018] Figure 6 is a schematic cross-section view of the system of Figure 5;

[0019] Figure 7 is an exploded isometric section view of an exemplary absorptive dressing with integral, wirelessly-powered pump, of the sort that may be used in the system of Figure 6.

DESCRIPTION OF EXAMPLE EMBODIMENTS

[0020] The following description of example embodiments provides information that enables a person skilled in the art to make and use the subject matter set forth in the appended claims, but it may omit certain details already well-known in the art. The following detailed description is, therefore, to be taken as illustrative and not limiting.

[0021] Figure 1 is a block diagram of an example embodiment of a therapy system 100 that can provide negative-pressure therapy with instillation of topical treatment solutions to a tissue site in accordance with this specification.

[0022] The term “tissue site” in this context broadly refers to a wound, defect, or other treatment target located on or within tissue, including, but not limited to, bone tissue, adipose tissue, muscle tissue, neural tissue, dermal tissue, vascular tissue, connective tissue, cartilage, tendons, or ligaments. A wound may include chronic, acute, traumatic, subacute, and dehisced wounds, partialthickness bums, ulcers (such as diabetic, pressure, or venous insufficiency ulcers), flaps, and grafts, for example. The term "tissue site” may also refer to areas of any tissue that are not necessarily wounded or defective, but are instead areas in which it may be desirable to add or promote the growth of additional tissue. For example, negative pressure may be applied to a tissue site to grow additional tissue that may be harvested and transplanted.

[0023] The therapy system 100 may include a source or supply of negative pressure, such as a negative-pressure source 105, and one or more distribution components. A distribution component is preferably detachable and may be disposable, reusable, or recyclable. A dressing, such as a dressing 110, and a fluid container, such as a container 115, are examples of distribution components that may be associated with some examples of the therapy system 100. As illustrated in the example of Figure 1, the dressing 110 may comprise or consist essentially of a tissue interface 120, a cover 125, or both in some embodiments. In some embodiments, the dressing 110 may comprise one or more layers configured to interface with the tissue site. In some embodiments, the dressing 110 may be configured to be positioned adjacent to a tissue site. For example, the dressing 110 may be configured to be in contact with a portion of the tissue site, substantially all of the tissue site, or a tissue site in its entirety. In some embodiments, the dressing 110 and/or one or more of its layers may be in substantially sheet form, for example comprising a generally planar structure having two opposite-facing planar surfaces and a depth or thickness orthogonal to the planar surfaces.

[0024] A fluid conductor is another illustrative example of a distribution component. A “fluid conductor,” in this context, broadly includes a tube, pipe, hose, conduit, or other structure with one or more lumina or open pathways adapted to convey a fluid between two ends. Typically, a tube is an elongated, cylindrical structure with some flexibility, but the geometry and rigidity may vary. Moreover, some fluid conductors may be molded into or otherwise integrally combined with other components. Distribution components may also include or comprise interfaces or fluid ports to facilitate coupling and de-coupling other components. In some embodiments, for example, a dressing interface may facilitate coupling a fluid conductor to the dressing 110. For example, such a dressing interface may be a SENSAT.R.A.C.™ Pad available from Kinetic Concepts, Inc. of San Antonio, Texas.

[0025] The therapy system 100 may also include a regulator or controller, such as a controller 130. Additionally, the therapy system 100 may include sensors to measure operating parameters and provide feedback signals to the controller 130 indicative of the operating parameters. As illustrated in Figure 1, for example, the therapy system 100 may include a first sensor 135 and a second sensor 140 coupled to the controller 130.

[0026] In some embodiments, the therapy system 100 may also optionally include a source of instillation solution. For example, a solution source 145 may be fluidly coupled to the dressing 110, as illustrated in the example embodiment of Figure 1. The solution source 145 may be fluidly coupled to a positive-pressure source, such as a positive-pressure source 150, a negative-pressure source such as the negative-pressure source 105, or both, in some embodiments. A regulator, such as an instillation regulator 155, may also be fluidly coupled to the solution source 145 and the dressing 110 to ensure proper dosage of instillation solution (e g. saline) to a tissue site. For example, the instillation regulator 155 may comprise a piston that can be pneumatically actuated by the negative-pressure source 105 to draw instillation solution from the solution source during a negative-pressure interval and to instill the solution to a dressing during a venting interval. Additionally or alternatively, the controller 130 may be coupled to the negative-pressure source 105, the positive-pressure source 150, or both, to control dosage of instillation solution to a tissue site. In some embodiments, the instillation regulator 155 may also be fluidly coupled to the negative-pressure source 105 through the dressing 110, as illustrated in the example of Figure 1.

[0027] Some components of the therapy system 100 may be housed within or used in conjunction with other components, such as sensors, processing units, alarm indicators, memory, databases, software, display devices, or user interfaces that further facilitate therapy. For example, in some embodiments, the negative-pressure source 105 may be combined with the controller 130, the solution source 145, and other components into a therapy unit.

[0028] In general, components of the therapy system 100 may be coupled directly or indirectly. For example, the negative-pressure source 105 may be directly coupled to the container 115 and may be indirectly coupled to the dressing 110 through the container 115. Coupling may include fluid, mechanical, thermal, electrical, or chemical coupling (such as a chemical bond), or some combination of coupling in some contexts. For example, the negative-pressure source 105 may be electrically coupled to the controller 130 and may be fluidly coupled to one or more distribution components to provide a fluid path to a tissue site. In some embodiments, components may also be coupled by virtue of physical proximity, being integral to a single structure, or being formed from the same piece of material.

[0029] A negative-pressure supply, such as the negative-pressure source 105, may be a reservoir of air at a negative pressure or may be a manual or electrically-powered device, such as a vacuum pump, a suction pump, a wall suction port available at many healthcare facilities, or a micropump, for example. “Negative pressure” generally refers to a pressure less than a local ambient pressure, such as the ambient pressure in a local environment external to a sealed therapeutic environment. In many cases, the local ambient pressure may also be the atmospheric pressure at which a tissue site is located. Alternatively, the pressure may be less than a hydrostatic pressure associated with tissue at the tissue site. Unless otherwise indicated, values of pressure stated herein are gauge pressures. References to increases in negative pressure typically refer to a decrease in absolute pressure, while decreases in negative pressure typically refer to an increase in absolute pressure. While the amount and nature of negative pressure provided by the negative-pressure source 105 may vary according to therapeutic requirements, the pressure is generally a low vacuum, also commonly referred to as a rough vacuum, between -5 mm Hg (-667 Pa) and -500 mm Hg (-66.7 kPa). Common therapeutic ranges are between -50 mm Hg (-6.7 kPa) and -300 mm Hg (-39.9 kPa).

[0030] The container 115 is representative of a container, canister, pouch, or other storage component, which can be used to manage exudates and other fluids withdrawn from a tissue site. In many environments, a rigid container may be preferred or required for collecting, storing, and disposing of fluids. In other environments, fluids may be properly disposed of without rigid container storage, and a re-usable container could reduce waste and costs associated with negative-pressure therapy. Some embodiments, in which the dressing 110 is absorptive, may not require a container, since the absorbency of the dressing an serve to manage the exudates or other fluids.

[0031] A controller, such as the controller 130, may be a microprocessor or computer programmed to operate one or more components of the therapy system 100, such as the negativepressure source 105. In some embodiments, for example, the controller 130 may be a microcontroller, which generally comprises an integrated circuit containing a processor core and a memory programmed to directly or indirectly control one or more operating parameters of the therapy system 100. Operating parameters may include the power applied to the negative-pressure source 105, the pressure generated by the negative-pressure source 105, or the pressure distributed to the tissue interface 120, for example. The controller 130 is also preferably configured to receive one or more input signals, such as a feedback signal, and programmed to modify one or more operating parameters based on the input signals.

[0032] Sensors, such as the first sensor 135 and the second sensor 140, are generally known in the art as any apparatus operable to detect or measure a physical phenomenon or property, and generally provide a signal indicative of the phenomenon or property that is detected or measured. For example, the first sensor 135 and the second sensor 140 may be configured to measure one or more operating parameters of the therapy system 100. In some embodiments, the first sensor 135 may be a transducer configured to measure pressure in a pneumatic pathway and convert the measurement to a signal indicative of the pressure measured. In some embodiments, for example, the first sensor 135 may be a piezo-resistive strain gauge. The second sensor 140 may optionally measure operating parameters of the negative-pressure source 105, such as a voltage or current, in some embodiments. Preferably, the signals from the first sensor 135 and the second sensor 140 are suitable as an input signal to the controller 130, but some signal conditioning may be appropriate in some embodiments. For example, the signal may need to be filtered or amplified before it can be processed by the controller 130. Typically, the signal is an electrical signal, but may be represented in other forms, such as an optical signal.

[0033] The tissue interface 120 can be generally adapted to partially or fully contact a tissue site. The tissue interface 120 may take many forms, and may have many sizes, shapes, or thicknesses, depending on a variety of factors, such as the type of treatment being implemented or the nature and size of a tissue site. For example, the size and shape of the tissue interface 120 may be adapted to the contours of deep and irregular shaped tissue sites. Any or all of the surfaces of the tissue interface 120 may have an uneven, coarse, or jagged profile.

[0034] In some embodiments, the tissue interface 120 may comprise or consist essentially of a manifold. For example, one or more layers of the dressing 110 may comprise or be configured as a manifold. A manifold in this context may comprise or consist essentially of a means for collecting or distributing fluid across the tissue interface 120 under pressure. For example, a manifold may be adapted to receive negative pressure from a source and distribute negative pressure through multiple apertures across the tissue interface 120, which may have the effect of collecting fluid from across a tissue site and drawing the fluid toward the source. In some embodiments, the fluid path may be reversed or a secondary fluid path may be provided to facilitate delivering fluid, such as fluid from a source of instillation solution, across a tissue site.

[0035] In some illustrative embodiments, a manifold may comprise a plurality of pathways, which can be interconnected to improve distribution or collection of fluids. In some illustrative embodiments, a manifold may comprise or consist essentially of a porous material having interconnected fluid pathways. Examples of suitable porous material that can be adapted to form interconnected fluid pathways (e.g., channels) may include cellular foam, including open-cell foam such as reticulated foam; porous tissue collections; and other porous material such as gauze or felted mat that generally include pores, edges, and/or walls. Liquids, gels, and other foams may also include or be cured to include apertures and fluid pathways. In some embodiments, a manifold may additionally or alternatively comprise projections that form interconnected fluid pathways. For example, a manifold may be molded to provide surface projections that define interconnected fluid pathways.

[0036] In some embodiments, the tissue interface 120 may comprise or consist essentially of reticulated foam having pore sizes and free volume that may vary according to needs of a prescribed therapy. For example, reticulated foam having a free volume of at least 90% may be suitable for many therapy applications, and foam having an average pore size in a range of 400-600 microns (40-50 pores per inch) may be particularly suitable for some types of therapy. The tensile strength of the tissue interface 120 may also vary according to needs of a prescribed therapy. For example, the tensile strength of foam may be increased for instillation of topical treatment solutions. The 25% compression load deflection of the tissue interface 120 may be at least 0.35 pounds per square inch, and the 65% compression load deflection may be at least 0.43 pounds per square inch. In some embodiments, the tensile strength of the tissue interface 120 may be at least 10 pounds per square inch. The tissue interface 120 may have a tear strength of at least 2.5 pounds per inch. In some embodiments, the tissue interface may be foam comprised of polyols such as polyester or polyether, isocyanate such as toluene diisocyanate, and polymerization modifiers such as amines and tin compounds. In some examples, the tissue interface 120 may be reticulated polyurethane foam such as found in GRANUFOAM™ dressing or V.A.C. VERAFLO™ dressing, both available from Kinetic Concepts, Inc. of San Antonio, Texas. [0037] The thickness of the tissue interface 120 may also vary according to needs of a prescribed therapy. For example, the thickness of the tissue interface may be decreased to reduce tension on peripheral tissue. The thickness of the tissue interface 120 can also affect the conformability of the tissue interface 120. In some embodiments, a thickness in a range of about 5 millimeters to 10 millimeters may be suitable.

[0038] The tissue interface 120 may be either hydrophobic or hydrophilic. In an example in which the tissue interface 120 may be hydrophilic, the tissue interface 120 may also wick fluid away from a tissue site, while continuing to distribute negative pressure to the tissue site. The wicking properties of the tissue interface 120 may draw fluid away from a tissue site by capillary flow or other wicking mechanisms. An example of a hydrophilic material that may be suitable is a polyvinyl alcohol, open-cell foam such as V.A.C. WHITEFOAM™ dressing available from Kinetic Concepts, Inc. of San Antonio, Texas. Other hydrophilic foams may include those made from polyether. Other foams that may exhibit hydrophilic characteristics include hydrophobic foams that have been treated or coated to provide hydrophilicity.

[0039] In some embodiments, the tissue interface 120 may be constructed from bioresorbable materials. Suitable bioresorbable materials may include, without limitation, a polymeric blend of polylactic acid (PLA) and polyglycolic acid (PGA). The polymeric blend may also include, without limitation, polycarbonates, polyfumarates, and capralactones. The tissue interface 120 may further serve as a scaffold for new cell-growth, or a scaffold material may be used in conjunction with the tissue interface 120 to promote cell -growth. A scaffold is generally a substance or structure used to enhance or promote the growth of cells or formation of tissue, 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 hydroxy apatites, carbonates, or processed allograft materials.

[0040] Some embodiments of the tissue interface 120 may comprise layers in addition to the manifold. For example, the tissue interface 120 of an absorptive dressing may comprise an absorbent layer, which may be characterized as exhibiting absorbency and/or as being adapted to absorb liquid (such as exudate) from the tissue site. In some embodiments, the absorbent layer may also be adapted to transfer negative pressure therethrough. In some embodiments, the absorbent layer may be configured to retain exudate and/or other fluids drawn from the tissue site during negative-pressure therapy, which may negate the necessity for separate fluid storage components such as an external fluid container. The absorbent layer may comprise any material capable of absorbing liquid (e.g. any absorbent material). In some embodiments, the absorbent layer may exhibit absorbency of at least 3 g saline/g, or at least 5 g saline/g, or from 8 to 20 g saline/g. In some embodiments, the absorbent layer may comprise superabsorbent material, such as superabsorbent polymer (SAP) particles or fibers. For example, some embodiments of the absorbent layer may comprise or consist essentially of one of the following: polyacrylate, sodium polyacrylate, polyacrylamide copolymer, ethylene-maleic anhydride copolymer, polyvinyl alcohol copolymer, cross-linked hydrophilic polymers, and combinations thereof. In some embodiments, the absorbent layer may be hydrophilic. In an example in which the absorbent layer is hydrophilic, the absorbent layer may also absorb or wick fluid away from one or more other components or layers of the dressing 110. In such an embodiment, the wicking properties of the absorbent layer may draw fluid away from one or more components or layers of the dressing 110 by capillary flow or other wicking mechanisms. An example of hydrophilic foam is a polyvinyl alcohol, open-cell foam. Other hydrophilic foams may include those made from polyether. Other foams that may exhibit hydrophilic characteristics include hydrophobic foams that have been treated or coated to provide hydrophilicity.

[0041] In some embodiments, the absorbent layer may have a bag-like structure for holding superabsorbent material. For example, the absorbent layer may be configured with superabsorbent material within a wicking pouch. In some embodiments, the pouch may comprise a first wicking layer and a second wicking layer. In some embodiments, the first wicking layer and the second wicking layer may be coupled around the pouch perimeter to form the enclosed pouch encapsulating (e.g. securely holding) the superabsorbent material to contain and prevent the superabsorbent material from migrating out of the pouch. For example, the first and second wicking layers may be coupled to each other using adhesive. The wicking layers may each comprise wicking material. The wicking material may be configured to be permeable to liquid (such as exudate), while retaining the superabsorbent material within the pouch. For example, the porosity of the wicking layers may be sufficiently small to prevent migration of the superabsorbent material through the wicking layers. The wicking layers may be configured to wick liquid along the superabsorbent material in a lateral direction normal to a thickness of the superabsorbent material within the pouch. Wicking of liquid laterally may enhance the distribution of liquid to the superabsorbent material, which may in turn speed absorption and/or allow for the superabsorbent material to maximize its absorbency. Examples of the wicking material may comprise or consist essentially of one of the following: Viscose, PET, Lidro™ non-woven material, a knitted polyester woven textile material, such as the one sold under the name InterDry® AG material from Coloplast A/S of Denmark, GORTEX® material, DuPont Softesse® material, etc., and combinations thereof. In some embodiments, the absorbent layer may serve as the manifold. For example, the absorbent layer may have manifolding properties, such that a separate manifold may not be necessary for negative-pressure therapy.

[0042] Some embodiments of the tissue interface 120 may comprise a protective layer. In some embodiments, the protective layer may act as a comfort layer, configured to improve comfort at the tissue site. In some embodiments, the protective layer may act as a fluid control layer, configured to minimize maceration, backflow of exudate out of the dressing to the tissue site, and/or tissue ingrowth from the tissue site into the dressing 110. The protective layer may be configured to allow fluid transport from the tissue site into the dressing 110 and/or to manifold during negative-pressure therapy. In some embodiments, the protective layer may be configured as the tissue-contact surface for the dressing, so that in use it may be located adjacent to the tissue site. In some embodiments, the protective layer may be located between the tissue-contact surface and the manifold and/or the absorbent layer. In some embodiments, the protective layer may be located between the tissue site (when the dressing is in use) and the manifold and/or absorbent layer.

[0043] In some embodiments, the protective layer may comprise a porous fabric, a porous fdm, or a polymeric fdm (e g. which may be liquid impermeable) with a plurality of fluid passages (e g. slits, slots, or fluid valves). In some embodiments, the protective layer may comprise or consist essentially of a woven, elastic material or a polyester knit textile substrate. In some embodiments, the protective layer may comprise or consist essentially of a liquid-impermeable, elastomeric material. For example, the protective layer may comprise or consist essentially of a polymer film. In some embodiments, for example, the protective layer may comprise or consist essentially of a hydrophobic polymer, such as a polyethylene film. The simple and inert structure of polyethylene can provide a surface that interacts little, if any, with biological tissues and fluids, providing a surface that may encourage the free flow of liquids and low adherence, which can be particularly advantageous for many applications. Other suitable polymeric films include polyurethanes, acrylics, polyolefin (such as cyclic olefin copolymers), polyacetates, polyamides, polyesters, copolyesters, PEBAX block copolymers, thermoplastic elastomers, thermoplastic vulcanizates, polyethers, polyvinyl alcohols, polypropylene, polymethylpentene, polycarbonate, styreneics, silicones, fluoropolymers, and acetates.

[0044] A thickness between 20 microns and 100 microns may be suitable for many applications. In some embodiments, the protective layer may be hydrophobic. In some embodiments, the protective layer may be hydrophilic. In some embodiments, the protective layer may be suitable for welding to other layers, such as the manifold.

[0045] Some embodiments of the protective layer may have one or more fluid passages, which can be distributed uniformly or randomly across the protective layer. The fluid passages may be bidirectional and pressure-responsive. For example, each of the fluid passages generally may comprise or consist essentially of an elastic passage that is normally unstrained to substantially reduce liquid flow, and can expand or open in response to a pressure gradient. In some embodiments, the fluid passage may comprise or consist essentially of perforations in the protective layer. Perforations may be formed by removing material from the protective layer. For example, perforations may be formed by cutting through the protective layer, which may also deform the edges of the perforations in some embodiments. In the absence of a pressure gradient across the perforations, the passages may be sufficiently small to form a seal or fluid restriction, which can substantially reduce or prevent liquid flow. Additionally or alternatively, one or more of the fluid passages may be an elastomeric valve that is normally closed when unstrained to substantially prevent liquid flow, and can open in response to a pressure gradient. A fenestration may be a suitable valve for some applications. Fenestrations may also be formed by removing material from the protective layer, but the amount of material removed and the resulting dimensions of the fenestrations may be up to an order of magnitude less than perforations, and may not deform the edges. [0046] For example, some embodiments of the fluid passages may comprise or consist essentially of one or more slits, slots or combinations of slits and slots in the protective layer. In some examples, the fluid passages may comprise or consist of linear slots having a length less than 4 millimeters and a width less than 1 millimeter. The length may be at least 2 millimeters, and the width may be at least 0.4 millimeters in some embodiments. A length of about 3 millimeters and a width of about 0.8 millimeters may be particularly suitable for many applications, and a tolerance of about 0.1 millimeter may also be acceptable. Such dimensions and tolerances may be achieved with a laser cutter, for example. Slots of such configurations may function as imperfect valves that substantially reduce liquid flow in a normally closed or resting state. For example, such slots may form a flow restriction without being completely closed or sealed. The slots can expand or open wider in response to a pressure gradient to allow increased liquid flow.

[0047] Some embodiments of the tissue interface 120 may comprise a diverter layer. For example, the diverter layer may be configured to direct fluid flow through the dressing 110 so that a specific portion of the dressing 110 (e .g . in proximity to a sensor or indicator) can only become saturated when substantially the entire dressing 110 has become saturated. In some embodiments, the diverter layer may be configured to direct fluid flow through the dressing (e.g. with respect to the negativepressure source 105) to facilitate fluid transfer throughout the entire absorbent layer (e.g. to ensure that the entire absorbent layer may become saturated). In some embodiments, the diverter layer may comprise one or more tortuous pathways, for example a plurality of tortuous pathways. In some embodiments, the diverter layer may comprise an impermeable lower surface with a fluid pathway therethrough. In some embodiments, the fluid pathway through the impermeable surface of the diverter layer may be located in proximity to the entry port for negative pressure in the dressing 110 (e.g. in proximity to the dressing interface) and/or distant from some specific portion of the dressing 110 (e.g. away from a sensor or indicator). In some embodiments, the diverter layer may be located between the manifold and the absorbent layer. In some embodiments, the diverter layer may be located between the absorbent layer and the cover 125.

[0048] In some embodiments, the cover 125 may provide a bacterial barrier and protection from physical trauma. The cover 125 may also be constructed from a material that can reduce evaporative losses and provide a fluid seal between two components or two environments, such as between a therapeutic environment and a local external environment. The cover 125 may comprise or consist of, for example, an elastomeric film or membrane that can provide a seal adequate to maintain a negative pressure at a tissue site for a given negative-pressure source. The cover 125 may have a high moisture-vapor transmission rate (MVTR) in some applications. For example, the MVTR may be at least 250 grams per square meter per twenty-four hours in some embodiments, measured using an upright cup technique according to ASTM E96/E96M Upright Cup Method at 38°C and 10% relative humidity (RH). In some embodiments, an MVTR up to 5,000 grams per square meter per twenty-four hours may provide effective breathability and mechanical properties. [0049] In some example embodiments, the cover 125 may be a polymer drape, such as a polyurethane film, that is permeable to water vapor but impermeable to liquid. Such drapes typically have a thickness in the range of 25-50 microns. For permeable materials, the permeability generally should be low enough that a desired negative pressure may be maintained. The cover 125 may comprise, for example, one or more of the following materials: polyurethane (PU), such as hydrophilic polyurethane; cellulosics; hydrophilic polyamides; polyvinyl alcohol; polyvinyl pyrrolidone; hydrophilic acrylics; silicones, such as hydrophilic silicone elastomers; natural rubbers; polyisoprene; styrene butadiene rubber; chloroprene mbber; polybutadiene; nitrile rubber; butyl rubber; ethylene propylene rubber; ethylene propylene diene monomer; chlorosulfonated polyethylene; polysulfide rubber; ethylene vinyl acetate (EVA); co-polyester; and polyether block polymide copolymers. Such materials are commercially available as, for example, Tegaderm® drape, commercially available from 3M Company, Minneapolis Minnesota; polyurethane (PU) drape, commercially available from Avery Dennison Corporation, Pasadena, California; polyether block polyamide copolymer (PEBAX), for example, from Arkema S.A., Colombes, France; and Inspire 2301 and Inpsire 2327 polyurethane films, commercially available from Expopack Advanced Coatings, Wrexham, United Kingdom. In some embodiments, the cover 125 may comprise INSPIRE 2301 having an MVTR (upright cup technique) of 2600 g/m²/24 hours and a thickness of about 30 microns.

[0050] An attachment device may be used to attach the cover 125 to an attachment surface, such as undamaged epidermis, a gasket, or another cover. The attachment device may take many forms. For example, an attachment device may be a medically-acceptable, pressure-sensitive adhesive configured to bond the cover 125 to epidermis around a tissue site. In some embodiments, for example, some or all of the cover 125 may be coated with an adhesive, such as an acrylic adhesive, which may have a coating weight of about 25-65 grams per square meter (g.s.m.). In some embodiments, the attachment device may comprise a sealing layer that may be configured to serve as the tissue-contact surface for the dressing, to attach the dressing to the tissue site, and/or to allow fluid communication between the tissue site and the dressing (e.g. through a plurality of apertures). Thicker adhesives, or combinations of adhesives, may be applied in some embodiments to improve the seal and reduce leaks. Other example embodiments of an attachment device may include a double-sided tape, paste, hydrocolloid, hydrogel, silicone gel, or organogel.

[0051] The solution source 145 may also be representative of a container, canister, pouch, bag, or other storage component, which can provide a solution for instillation therapy. Compositions of solutions may vary according to a prescribed therapy, but examples of solutions that may be suitable for some prescriptions include hypochlorite-based solutions, silver nitrate (0.5%), sulfur-based solutions, biguanides, cationic solutions, and isotonic solutions.

[0052] In operation, the tissue interface 120 may be placed within, over, on, or otherwise proximate to atissue site. If the tissue site is a wound, for example, the tissue interface 120 may partially or completely fill the wound, or it may be placed over the wound. The cover 125 may be placed over the tissue interface 120 and sealed to an attachment surface near a tissue site. For example, the cover 125 may be sealed to undamaged epidermis peripheral to a tissue site. Thus, the dressing 110 can provide a sealed therapeutic environment proximate to a tissue site, substantially isolated from the external environment, and the negative-pressure source 105 can reduce pressure in the sealed therapeutic environment.

[0053] In general, exudate and other fluid flow toward lower pressure along a fluid path. Thus, the term “downstream” may refer to a location in a fluid path relatively closer to a source of negative pressure or further away from a source of positive pressure. Conversely, the term “upstream” may refer to a location relatively further away from a source of negative pressure or closer to a source of positive pressure. Similarly, it may be convenient to describe certain features in terms of fluid “inlet” or “outlet” in such a frame of reference. This orientation is generally presumed for purposes of describing various features and components herein. However, the fluid path may also be reversed in some applications, such as by substituting a positive-pressure source for a negative-pressure source, and this descriptive convention should not be construed as a limiting convention.

[0054] Negative pressure applied across the tissue site through the tissue interface 120 in the sealed therapeutic environment can induce macro-strain and micro-strain in the tissue site. Negative pressure can also remove exudate and other fluid from a tissue site, which can be collected in container 115.

[0055] In some embodiments, the controller 130 may receive and process data from one or more sensors, such as the first sensor 135. The controller 130 may also control the operation of one or more components of the therapy system 100 to manage the pressure delivered to the tissue interface 120. In some embodiments, controller 130 may include an input for receiving a desired target pressure and may be programmed for processing data relating to the setting and inputting of the target pressure to be applied to the tissue interface 120. In some example embodiments, the target pressure may be a fixed pressure value set by an operator as the target negative pressure desired for therapy at a tissue site and then provided as input to the controller 130. The target pressure may vary from tissue site to tissue site based on the type of tissue forming a tissue site, the type of injury or wound (if any), the medical condition of the patient, and the preference of the attending physician. After selecting a desired target pressure, the controller 130 can operate the negative -pressure source 105 in one or more control modes based on the target pressure and may receive feedback from one or more sensors to maintain the target pressure at the tissue interface 120.

[0056] Figure 2 is a graph illustrating additional details of an example control mode that may be associated with some embodiments of the controller 130. In some embodiments, the controller 130 may have a continuous pressure mode, in which the negative-pressure source 105 is operated to provide a constant target negative pressure, as indicated by line 205 and line 210, for the duration of treatment or until manually deactivated. Additionally or alternatively, the controller may have an intermittent pressure mode, as illustrated in the example of Figure 2. In Figure 2, the x-axis represents time and the y-axis represents negative pressure generated by the negative -pressure source 105 over time. In the example of Figure 2, the controller 130 can operate the negative-pressure source 105 to cycle between a target pressure and atmospheric pressure. For example, the target pressure may be set at a value of 135 mmHg, as indicated by line 205, for a specified period of time (e.g., 5 min), followed by a specified period of time (e.g., 2 min) of deactivation, as indicated by the gap between the solid lines 215 and 220. The cycle can be repeated by activating the negative-pressure source 105, as indicated by line 220, which can form a square wave pattern between the target pressure and atmospheric pressure.

[0057] In some example embodiments, the increase in negative-pressure from ambient pressure to the target pressure may not be instantaneous. For example, the negative-pressure source 105 and the dressing 110 may have an initial rise time, as indicated by the dashed line 225. The initial rise time may vary depending on the type of dressing and therapy equipment being used. For example, the initial rise time for one therapy system may be in a range of about 20-30 mmHg/second and in a range of about 5-10 mmHg/second for another therapy system. If the therapy system 100 is operating in an intermittent mode, the repeating rise time, as indicated by the solid line 220, may be a value substantially equal to the initial rise time as indicated by the dashed line 225.

[0058] Figure 3 is a graph illustrating additional details that may be associated with another example pressure control mode in some embodiments of the therapy system 100. In Figure 3, the x- axis represents time and the y-axis represents negative pressure generated by the negative-pressure source 105. The target pressure in the example of Figure 3 can vary with time in a dynamic pressure mode. For example, the target pressure may vary in the form of atnangular waveform, varying between a negative pressure of 50 and 135 mmHg with a rise time 305 set at a rate of +25 mmHg/min. and a descent time 310 set at -25 mmHg/min. In other embodiments of the therapy system 100, the triangular waveform may vary between negative pressure of 25 and 135 mmHg with a nse time 305 set at a rate of +30 mmHg/min and a descent time 310 set at -30 mmHg/min.

[0059] In some embodiments, the controller 130 may control or determine a variable target pressure in a dynamic pressure mode, and the variable target pressure may vary between a maximum and minimum pressure value that may be set as an input prescribed by an operator as the range of desired negative pressure. The variable target pressure may also be processed and controlled by the controller 130, which can vary the target pressure according to a predetermined waveform, such as a triangular waveform, a sine waveform, or a saw-tooth waveform. In some embodiments, the waveform may be set by an operator as the predetermined or time-varying negative pressure desired for therapy.

[0060] Figure 4 is a chart illustrating details that may be associated with an example method 400 of operating the therapy system 100 to provide negative-pressure treatment and instillation treatment to the tissue interface 120. In some embodiments, the controller 130 may receive and process data, such as data related to instillation solution provided to the tissue interface 120. Such data may include the type of instillation solution prescribed by a clinician, the volume of fluid or solution to be instilled to a tissue site (“fill volume”), and the amount of time prescribed for leaving solution at a tissue site (“dwell time”) before applying a negative pressure to the tissue site. The fill volume may be, for example, between 10 and 500 mL, and the dwell time may be between one second to 30 minutes. The controller 130 may also control the operation of one or more components of the therapy system 100 to instill solution, as indicated at 405. For example, the controller 130 may manage fluid distributed from the solution source 145 to the tissue interface 120. In some embodiments, fluid may be instilled to a tissue site by applying a negative pressure from the negative-pressure source 105 to reduce the pressure at the tissue site, drawing solution into the tissue interface 120, as indicated at 410. In some embodiments, solution may be instilled to a tissue site by applying a positive pressure from the positivepressure source 160 to move solution from the solution source 145 to the tissue interface 120, as indicated at 415. Additionally or alternatively, the solution source 145 may be elevated to a height sufficient to allow gravity to move solution into the tissue interface 120, as indicated at 420.

[0061] The controller 130 may also control the fluid dynamics of instillation at 425 by providing a continuous flow of solution at 430 or an intermittent flow of solution at 435. Negative pressure may be applied to provide either continuous flow or intermittent flow of solution at 440. The application of negative pressure may be implemented to provide a continuous pressure mode of operation at 445 to achieve a continuous flow rate of instillation solution through the tissue interface 120, or it may be implemented to provide a dynamic pressure mode of operation at 450 to vary the flow rate of instillation solution through the tissue interface 120. Alternatively, the application of negative pressure may be implemented to provide an intermittent mode of operation at 455 to allow instillation solution to dwell at the tissue interface 120. In an intermittent mode, a specific fill volume and dwell time may be provided depending, for example, on the type of tissue site being treated and the type of dressing being utilized. After or during instillation of solution, negative -pressure treatment may be applied at 460. The controller 130 may be utilized to select a mode of operation and the duration of the negative pressure treatment before commencing another instillation cycle at 465 by instilling more solution at 405.

[0062] Some embodiments may have the negative-pressure source 105, such as a pump configured to provide negative pressure to the dressing 110, physically attached to the dressing 110. For example, the dressing 110 may be a pre-formed unit having an integral pump. In some embodiments, the pump may be removably and/or wirelessly powered, for example with the power source isolated from the pump and/or dressing 110. In some embodiments, the power components, such as the power source and/or controller, may be physically separate from the fluid components and/or may be easily separable from the fluid components. This may allow for the power components to be re-used with multiple dressings, for example without substantial risk of contamination, while the fluid components may be single-use and/or disposable. In some embodiments, the dressing 110 may be an absorbent dressing. Figures 5-6 illustrate an example of the therapy system 100 configured with the pump 505 integral to the dressing 110 and configured for wireless power transmission to the integral pump 505. [0063] Figure 5 is a schematic diagram illustrating an example of the therapy system 100 of Figure 1. In some embodiments, a pump 505 may be attached to the dressing 110, fluidly coupled to the dressing 110, and/or configured to provide negative pressure to/within the dressing 110. In some embodiments, the pump 505 may be disposed within the dressing 110. A power source 510 for the system 100 (e g. to provide power to the pump 505) may be isolated from the pump 505 and/or external to the dressing 110, for example with the power source 510 located separate from the dressing 110 and the pump 505. Some embodiments may further comprise a means to remotely or wirelessly couple the power source 510 to the pump 505, so that the power source 510 may provide power to the pump 505 wirelessly. For example, the means to wirelessly couple the power source 510 to the pump 505 may comprise a wireless power transmission device, such as an inductive power transmission system. In some embodiments, the wireless power transmission device may comprise two portions: a first portion located external to the dressing 110 and a second portion which may be located within the dressing 110, with the first portion configured to transmit power wirelessly to the second portion. The first portion may be electrically coupled to the power source 510, and the second portion may be electrically coupled to the pump 505 , so that the wireless power transmission device may wirelessly couple the power source 510 to the pump 505 to provide power transfer to the pump 505. For example, the first portion may comprise a primary (e.g. transmitter) induction coil 515, and the second portion may comprise a secondary (e g. receiver) induction coil 520, with the primary induction coil 515 configured to induce power in the secondary induction coil 520 upon receiving power from the power source 510. For example, the primary induction coil 515 may generate a magnetic field when energized, and the magnetic field may induce voltage and/or current in the secondary induction coil 520 and thereby power the pump 510.

[0064] In some embodiments, the system 100 may further include a pump actuator configured to activate the pump 510 whenever negative pressure in the dressing 110 drops below a pre-set level or threshold (e.g. atherapeutic level, such as -125 mmHg +/- 20 mmHg). For example, the pump actuator may comprise a pressure switch 525 configured to activate the pump 505 by completing the drive circuit for the pump 505 when the negative pressure in the dressing 110 is less than the pre-set threshold, and to deactivate the pump 505 by breaking the pump drive circuit when the negative pressure in the dressing 110 meets (e.g. is at or above) the pre-set threshold. In some embodiments, the pressure switch 525 may be biased, for example by a spring or other biasing element, towards a closed position with the pump drive circuit closed to allow current induced from the primary induction coil 515 to the secondary induction coil 520 to flow to the pump 505; and the pressure switch 525 may be configured so that therapeutic negative pressure in the dressing 110 overcomes the bias to an open position with the pump drive circuit broken or open, to prevent current flow to the pump 505. In some embodiments, the bias element may comprise a hysteresis dampener, which may comprise an absorber component such as closed cell foam configured to dampen hysteresis and prevent sensor flutter. [0065] Some system embodiments may further comprise a controller 130, such as a processor, configured to operate the power source 505. In some embodiments, the controller 130 and the power source 505 may share a common housing and/or may integrally form a controller unit or therapy device . In some embodiments, the controller 130 may be configured to intermittently power the primary induction coil 515 using the power source 510, thereby intermittently providing power through induction to the pump drive circuit. Intermittent power delivery may help in power conservation. When the controller 130 intermittently provides power to the primary induction coil 515 (and thereby to the pump drive circuit and/or pump 505, through induction), it may work in conjunction with the pump actuator, such as pressure switch 525, to operate the pump 505. For example, the controller 130 may periodically poll the primary induction coil 515 to determine if negative pressure in the dressing 110 has fallen below the pre-set threshold. Polling may be accomplished by briefly energizing the primaiy induction coil 515, using the power source 510, and determining if the current drain at the primary induction coil 515 is sufficiently high to indicate that the pump 505 is running. Due to the configuration of the pump actuator with respect to the pump drive circuit and/or pump 505, if the pump 505 runs when the primary induction coil 515 is energized, then the controller 130 can determine that the negative pressure in the dressing 110 is below the pre-set threshold. In some embodiments, polling may energize the primary induction coil 515 for about 0.5-1 second, polling may energize the primary induction coil 515 using about 0.5-1 Watt of power from the power source 505, and/or a current drain of about 0.5-1 Watt may be indicative that the pump is running and/or that negative pressure in the dressing 110 has fallen below the pre-set threshold.

[0066] Responsive to a determination (e.g. through polling) that negative pressure is below the pre-set threshold, the primary induction coil 515 may be energized to power the pump 505 to provide negative pressure to the dressing 110. For example, energizing the primary induction coil 515 may comprise continuing and/or maintained energizing from the polling, and the current drain at the primary induction coil 515 may be monitored to determine when power is no longer needed for the pump 505. For example, the controller 130 may be configured to determine that power is no longer needed when the pump 505 is no longer running, for example due to meeting the pre-set threshold for negative pressure within the dressing 110 and having the pump actuator disconnect the pump 505 from the secondary induction coil 520. Energy to the primary induction coil 515 may be maintained until there is an indication that the pump 505 has switched off, since the pump 505 switching off may indicate that the negative pressure within the dressing 110 has reached the pre-set threshold (e.g. based on the action of the pressure switch 525). For example, the primary induction coil 515 may be energized until the current drain at the primary induction coil 515 is no longer sufficiently large to indicate that the pump 505 is running, such as when the current drain drops by at least 80% of its initial level, or when the current drain drops by at least 80% of the anticipated draw when the pump 505 is running. Once the controller 130 determines that the negative pressure in the dressing 110 meets the pre-set threshold, the controller 130 may deactivate the power source 510 and/or de-energize the primary induction coil 515. Then, the controller 130 may resume polling periodically to determine when to re-energize the primary induction coil 515 and thereby the pump 505. For example, the controller 130 may poll the primary induction coil 515 about every 2-3 minutes.

[0067] In some embodiments, historical polling data can be used to iteratively adjust the amount of time between polling. For example, the controller 130 may determine that the time between polling instances should be lengthened if one or more (e g. successive) previous polling instances determined that power was not needed at the pump 505, for example determining that negative pressure within the dressing 110 had not fallen below the pre-set threshold; or the controller 130 may determine that the time between polling instances should be shortened if one or more (e.g. successive) previous polling instances determined that power was needed at the pump 505, for example determining that negative pressure within the dressing 110 had fallen below the pre-set threshold. In some embodiments, the controller 130 may determine that the time between polling instances should be shortened if the pump needed to run longer at one or more (e.g. successive) previous polling instances; or the controller 130 may determine that the time between polling instances should be lengthened if there was no or shortened pump activation at one or more (e.g. successive) previous polling instances. In some embodiments, a leak may be indicated by the controller 130, for example via an alarm or warning indication, if the time between powering the pump 505 is sufficiently short. For example, if the pump 505 needs to remain active continuously, or if the pump 505 must run for 2-3 minutes each (e g. multiple successive) polling instances to provide negative pressure within the dressing 110 that meets the preset threshold, this may indicate a gross leak for alarm. In some embodiments, an alarm or alert may be activated if close-coupling of the first portion and the second portion of the wireless power transmission device is not detected. For example, if sufficient time interval passes without activation of the pump 505, this may be indicative that the first and second portions are not close-coupled, since even a well- sealed dressing should require occasional pump activation. Alternatively, alignment sensors, such as hall-effect sensors, for determining when the primary induction coil 515 and the secondary induction coil 520 are properly aligned may also be used to detect whether or not there is close-coupling.

[0068] In some embodiments, the controller 130 may be configured to permanently and/or continuously power the primary coil 515. Some such configurations may not even require a controller, but rather may be configured so that the power source 510 directly and/or continuously powers the primary induction coil 515 when the system is in use. In such embodiments, the pump actuator, such as pressure switch 525, may function independently to operate the pump 505, since power may be continuously available at the pump drive circuit through induction. For example, when the pressure switch 515 is closed to complete the pump drive circuit (e.g. due to negative pressure in the dressing 110 falling below the pre-set threshold and overcoming the bias), power may flow to the pump 505; and when the pressure switch 525 is open (e g. due to negative pressure in the dressing 110 meeting the pre-set threshold, so that the bias opens the pressure switch 525), the pump drive circuit may be broken to prevent the continuously available induced power from reaching the pump 505. [0069] In some embodiments, the dressing 110 may not comprise any smart elements. For example, all smart elements, such as the controller 130, power source 510, and/or primary induction coil 515, may be located external to the dressing 110, may be easily separable and/or removable from the dressing 110, and/or may only be coupled to the dressing 110 wirelessly. While the embodiment shown in Figure 5 illustrates a system in which the pump 505 is internal to the dressing 110, in other embodiments the pump 505 may be disposed on an external surface of the dressing 110 and in fluid communication with the dressing 110. For example, the pump 505 may be configured to provide negative pressure within the dressing 110 through the cover. In such embodiments, the pump 505 may be permanently attached to the external surface of the dressing 110, or may be removably attached to the external surface of the dressing 110. In some embodiments, the secondary induction coil may also be external to the dressing 110, for example mounted on the pump 505. Regardless, the primary induction coil 515 may be configured to be positioned with respect to the pump 505 and the secondary induction coil 520 so as to allow for inductive power transfer from the power source 510 to the pump 505.

[0070] Figure 6 is a schematic cross-section view of the system 100 of Figure 5. As described above with respect to Figure 5, the embodiment of Figure 6 illustrates the pump 505 located within the dressing 110, as well as the wireless power transfer system (with primary induction coil 515 and secondary induction coil 520) linking the power source 510 to the pump 505. In some embodiments, the dressing 110 may be an absorptive dressing. For example, the absorptive dressing 110 may comprise an absorbent layer 605. In some embodiments, the absorbent layer 605 may be configured for manifolding, so that an additional, separate manifold may not be necessary within the dressing 110 to allow for negative -pressure therapy using the dressing 110. In some embodiments, the absorptive dressing 110 may comprise superabsorbent material or particles.

[0071] Some embodiments may further comprise an alignment sensor, configured to determine if the two portions of the wireless power transmission device (e.g. the primary induction coil 515 and the secondary induction coil 520) are aligned. For example, the alignment sensor may comprise a reed switch 610 or magnetic sensor in the first portion (e g. the primary induction coil 515) and a magnet 615 in the second portion (e.g. the secondary induction coil 520), or vice versa. In some embodiments, the alignment sensor may be integrated into the center of the wireless power transmission device, for example with the reed switch 610 integrated into the center of the primary induction coil 515, and the opposing magnet 615 integrated into the center of the secondary induction coil 520. In some embodiments, the controller 130 may be configured to activate an alarm when the two portions of the wireless power transmission device are not aligned and/or are located too far apart to effectively transmit power therebetween (e.g. not close-coupled).

[0072] In some embodiments, the dressing 110 with integral pump 505 may be pre-assembled as single unit. In some embodiments in which the dressing 110 comprises an absorbent layer 605, the system 100 may not include any fluid storage container external to the dressing 110. Rather, the system 100 may be configured so that fluid, such as exudate from the tissue site during use, may be trapped only in the absorbent dressing 110.

[0073] Figure 7 is an exploded isometric sectional view of an exemplary absorptive dressing 110 with integral, wirelessly-powered pump 505, of the sort that may be used in the system of Figure 6. As shown in Figure 7, some embodiments may comprise a cover 125, which may be configured to substantially prevent fluid flow therethrough, to provide a sealed negative-pressure environment on the tissue site, and/or to be disposed over the absorptive layer 605 and the pump 505 (typically including the secondary induction coil 520 and the pressure switch 525). Some embodiments may further comprise a vent 720 configured to fluidly couple the pump 505 to an external environment. For example, the vent 720 may be configured to fluidly couple the pump 505 to the external environment through the cover 125. In some embodiments, the cover 125 may include a vent opening 722 which may be in fluid communication with the vent 720, for venting of the internal, integral pump 505. In some embodiments, the vent 720 may be sealed around its perimeter (e.g. around vent opening 722) to prevent fluid flow between the dressing 110 and the external environment, except through the pump 505. In some embodiments, the absorptive dressing 110 may further comprise a manifold 705, and the cover 125 may also be configured to cover the separate manifold 705. In some embodiments, the absorbent layer 605 may be located between the manifold 705 and the cover 125. For example, the manifold 705 may be stacked with the absorbent layer 605, opposite the cover 125. In some embodiments, the manifold 705 may be configured to be located between the tissue site and the pump 505 and/or absorbent layer 605. For example, the manifold 705 may form the tissue-contact surface for the tissue interface.

[0074] In some embodiments, the pump 505 may be in fluid communication with the manifold 705 and the external environment and/or may be configured to provide negative pressure to the manifold 705. In some embodiments, the absorbent layer 605 may be fluidly coupled to the pump 505, for example through the manifold 705. In some embodiments, the manifold 705 may be fluidly coupled to the tissue site and the pump. For example, the manifold 705 may fluidly couple the pump 505 to the tissue site. In some embodiments, the dressing 110 may comprise a cavity 710 configured to receive the pump 505. For example, the cavity 710 may extend into the tissue interface from the cover 125 of the dressing 110, through the absorbent layer 605, and/or partially into the manifold 705. In some embodiments, the absorbent layer 605 may be located around the pump 505 when the pump 505 is located in the cavity 710.

[0075] Some embodiments may further comprise a filter 715 configured to prevent liquid from entering the pump 505 (e.g. from the manifold 705, absorbent layer 605, or tissue site), while allowing airflow (e.g. communication of negative pressure) between the pump 505 and the dressing 110 (e.g. the manifold 705 and/or the absorbent layer 605). In some embodiments, the filter 715 may be configured to allow for continued operation of the pump 505 providing negative pressure therapy to the dressing 110, regardless of the presence of exudate or other liquid in the dressing 110. In some embodiments, the filter 715 may be located at the interface between the pump 505 and the manifold 705. In some embodiments, the filter 715 may span a port 713 in the pump housing 718 which is configured to allow communication of negative pressure from the pump 505 to the manifold 705, the absorbent layer 605, and/or the tissue site. In some embodiments, the pump 505, the receiver portion of the wireless power transmission device (e.g. the secondary induction coil 520), and/or the pressure switch 525 may be located within the pump housing 718, which may be configured to shield the internal components from exposure to liquids such as exudate in the dressing 110. In some embodiments, the pump housing 718 may be sealed with respect to liquid and/or gas communication with the dressing 110, except for communication of the pump 505 with the manifold 705 and/or absorbent layer 605 through the port 713 and filter 715. In some embodiments, the vent 720 may be configured to allow fluid communication between the pump 505 and the external environment, for example through an external surface 719 of the pump housing 718 and the cover 125. Some embodiments may also include a second filter 725 spanning the vent 720, which may comprise one or more of the following: a bacterial filter, a hydrophobic filter, a dust/particle filter, and a charcoal filter. In some embodiments, the pump housing 718, with its internal components, may be located within the cavity 710 under the cover 125 within the dressing 110. In some embodiments, the pump 505, secondary induction coil 520, pressure switch 525, and/or filter 715 may be a pre-assembled unit, for example located within the pump housing 718.

[0076] In some embodiments, the transmitter portion of the wireless power transmission device (e.g. the primary induction coil 515) may be removably attached to the exterior surface of the dressing 110 (e.g. the external surface of the cover 125). For example, an adhesive ring 730 may removably attach the primary induction coil 515 to the cover 125. In some embodiments, the adhesive ring 730 may comprise light switchable adhesive. For example, once adhered, the bond may be strong until release is triggered by exposure to specific light (such as UV light) that deactivates the adhesive or reduces the adhesion strength of the adhesive ring 730 to allow for release. In some embodiments, the controller may be configured to activate a light emitter and/or diffuser, which may be located within the primary induction coil 515, whenever release is desired.

[0077] In some embodiments, the cover 125, the manifold 705, the absorbent layer 605, the pump 505, the secondary induction coil 520, and the pressure switch 525, or various combinations may be assembled before application or at a tissue site. In some embodiments, the dressing 110 may be provided as a single unit.

[0078] In use, methods for providing negative-pressure therapy to a tissue site with a dressing 110 and/or therapy system 100 similar to that described with respect to Figures 5-7 may comprise the following steps: applying an absorptive negative-pressure dressing with an integral pump to the tissue site; and wirelessly providing power to the pump. In some embodiments, wirelessly providing power may comprise aligning a transmitter coil and a receiver coil of an inductive power coupling system and inducing power to the receiver coil by energizing the transmitter coil. Some method embodiments may further comprise monitoring alignment of the coils and activating an alarm when the coils are not aligned. For example, the controller may receive alignment data from a reed switch sensor, and responsive to that data, may activate an alarm indicative of misalignment. Some embodiments may further comprise electrically coupling the receiver coil to the pump whenever negative pressure in the absorptive dressing falls below a pre-set threshold, and electrically uncoupling the receiver coil from the pump whenever the negative pressure in the absorptive dressing meets (e.g. is at or above) the preset threshold For example, a pump actuator may electrically couple and/or uncouple the pump to the receiver coil, based on negative pressure within the dressing (e.g. if the negative pressure meets the preset threshold or not). In some embodiments, wirelessly providing power may comprise continuously energizing the transmitter coil. For example, the power source may continuously power the transmitter coil, by direct coupling; or the controller may direct power continuously from the power source to the transmitter coil. In other embodiments, wirelessly providing power may comprise intermittently energizing the transmitter coil (e.g. based on the controller activating or connecting the power source to the transmitter coil). For example, wirelessly providing power may comprise energizing the transmitter coil when the negative pressure in the absorptive dressing falls below a pre-set threshold and/or energizing the transmitter coil based on current drain at the transmitter coil. Some embodiments may further comprise determining whether negative pressure in the absorptive dressing is below the pre-set threshold based on current drain at the transmitter coil.

[0079] In some embodiments, wirelessly providing power may comprise polling the transmitter coil to determine if negative pressure has fallen below the pre-set threshold (e.g. by determining that the pump is running, which may be indicative of low negative pressure based on the configuration of the pump actuator). Some embodiments may further comprise, upon determining that negative pressure has fallen below the pre-set threshold, energizing the transmitter coil (e.g. using the power source) and/or maintaining energy to the transmitter coil until negative pressure rises above the pre-set threshold. Some embodiments may further comprise determining when to de-energize the transmitter coil, for example based on current drain at the transmitter coil. For example, the controller may determine when to de-energize the transmitter coil by detecting when current drain at the transmitter coil has dropped by at least 80% of the initial value or 80% of the anticipated close-coupled current draw of the pump. Some embodiments may further comprise re-polling the transmitter coil periodically. For example, the transmitter coil may be re-polled periodically when the transmitter coil is not being energized, to determine if there is a need to energize the transmitter coil and/or if negative pressure in the dressing has fallen below the pre-set threshold. In some embodiments, polling the transmitter coil, energizing the transmitter coil, determining when to de-energize the transmitter coil, and/or de-energizing the transmitter coil may be iterative processes. Some embodiments may further comprise adjusting the frequency of polling based on historical data (e.g. past polling interval results data). Some embodiments may further comprise removing the dressing from the tissue site and/or disposing of the dressing. Some embodiments may further comprise reusing the transmiter coil and/or controller unit (e.g. power source and/or processor) with another dressing having another pump and another receiver coil (e.g. on another tissue site/patient).

[0080] The systems, apparatuses, and methods described herein may provide significant advantages. For example, the dressings and/or systems may allow for negative-pressure therapy at a tissue site. Absorptive dressings may allow for increased patient mobility, for example by decreasing the bulk of the system by obviating the need for an external fluid container. Having an integral pump attached to and/or located within the dressing may further increase patient mobility, by providing for a less cumbersome system. Powering the pump using wireless power transmission, such as an inductive power coupling system, may allow effective separation, isolation, and/or segregation of the smart elements of the system (e.g. the controller, power source, and/or transmitter coil) from the fluid components of the system (e.g. the dressing and pump). This may isolate the controller and power source from fluid infiltration of the sort which may contaminate the elements, and may allow for the easy re-use of these smart components with another dressing. As such, the smart components may be easily re-used with another dressing and/or another patient or tissue site, while the dressing elements may be disposable. Having a disposable dressing with integral pump may improve patient convenience, for example by simplifying installation at the tissue site. In some embodiments, removing the more expensive smart components from the dressing may allow the dressing, which may have the components with the shortest lifespan and/or lowest cost, to effectively be disposable. By separating the reusable components from the dressing and the fluid components (e.g. pump), premature disposal of the smart components may be avoided. In some embodiments, power may be conserved by minimizing power expenditures except when negative pressure in the dressing has fallen below the preset therapeutic threshold. In some embodiments, sensors may also detect when the inductive power coupling system is aligned and operable, helping to ensure easy, effective set-up. For example, the sensors may make it easy to use the smart components (e.g. controller, power supply, and/or transmitter coil) with a plurality of dressings and/or a plurality of patients, allowing the power source to be easily synced up with different disposable dressings.

[0081] If something is described as “exemplary” or an “example”, it should be understood that refers to a non-exclusive example. The terms “about” or “approximately” or the like, when used with a number, may mean that specific number, or alternatively, a range in proximity to the specific number as understood by persons of skill in the art field (for example, +/-10%). Use of broader terms such as “comprises”, “includes”, and “having” should be understood to provide support for narrower terms such as “consisting of’, “consisting essentially of’, and “comprised substantially of’. Use of the term “optionally”, “may”, “might”, “possibly”, “could”, “can”, “would”, “should”, “preferably”, “typically”, “often” and the like with respect to any element, component, feature, characteristic, etc. of an embodiment means that the element, component, feature, characteristic, etc. is not required, or alternatively, the element, component, feature, characteristic, etc. is required, both alternatives being within the scope of the embodiment s). Such element, component, feature, characteristic, etc. may be optionally included in some embodiments, or it may be excluded (e .g . forming alternative embodiments, all of which are included within the scope of disclosure). Section headings used herein are provided for consistency and convenience, and shall not limit or characterize any invention(s) set out in any claims that may issue from this disclosure. If a reference numeral is used to reference a specific example of a more general term, then that reference numeral may also be used to refer to the general term (or vice versa).

[0082] While shown in a few illustrative embodiments, a person having ordinary skill in the art will recognize that the systems, apparatuses, and methods described herein are susceptible to various changes and modifications that fall within the scope of the appended claims. Moreover, descriptions of various alternatives using terms such as “or” do not require mutual exclusivity unless clearly required by the context, and the indefinite articles "a" or "an" do not limit the subject to a single instance unless clearly required by the context. Components may be also be combined or eliminated in various configurations for purposes of sale, manufacture, assembly, or use. For example, in some configurations the dressing, the container, or both may be eliminated or separated from other components for manufacture or sale. In other example configurations, the controller may also be manufactured, configured, assembled, or sold independently of other components.

[0083] The appended claims set forth novel and inventive aspects of the subject matter described above, but the claims may also encompass additional subject matter not specifically recited in detail. For example, certain features, elements, or aspects may be omitted from the claims if not necessary to distinguish the novel and inventive features from what is already known to a person having ordinary skill in the art. Features, elements, and aspects described in the context of some embodiments may also be omitted, combined, or replaced by alternative features serving the same, equivalent, or similar purpose without departing from the scope of the invention defined by the appended claims. Also, features, elements, and aspects descnbed with respect to a particular embodiment may be combined with features, elements, and aspects described with respect to one or more other embodiments.

Claims

26 CLAIMS What is claimed is:

1. A system for providing negative pressure wound therapy, comprising: an absorptive dressing; a pump attached to the absorptive dressing, fluidly coupled to the absorptive dressing, and configured to provide negative pressure to the absorptive dressing; a power source isolated from the pump; and a wireless power transmission device configured to wirelessly couple the power source to the pump.

2. The system of claim 1, further comprising a pump actuator configured to activate the pump whenever negative pressure in the absorptive dressing drops below a pre-set threshold.

3. The system of claim 2, wherein the pump is disposed within the absorptive dressing.

4. The system of claim 3, wherein: the absorptive dressing comprises: a manifold, an absorbent layer, and a cover; the cover is configured to substantially prevent fluid flow therethrough and to be disposed over the manifold, the absorbent layer, and the pump; and the cover further comprises a vent configured to fluidly couple the pump to an external environment through the cover.

5. The system of claim 1, further comprising a filter configured to prevent liquid from entering the pump, while allowing communication of negative pressure from the pump to the absorptive dressing.

6. The system of claim 1, further comprising a processor configured to operate the power source.

7. The system of claim 3, wherein the wireless power transmission device comprises two portions: a first portion located external to the absorptive dressing and a second portion located within the absorptive dressing; wherein the first portion is configured to transmit power wirelessly to the second portion.

8. The system of claim 7, wherein the first portion is electrically coupled to the power source, and the second portion is electrically coupled to the pump.

9. The system of claim 1, wherein the wireless power transmission device comprises a primary coil and a secondary coil, wherein the primary coil is configured to induce power in the secondary coil upon receiving power from the power source.

10. The system of claim 2, wherein the pump actuator comprises a pressure switch configured to activate the pump when the negative pressure in the absorptive dressing is less than the pre-set threshold, and to deactivate the pump when the negative pressure meets the pre-set threshold.

11. The system of claim 9, further comprising a processor configured to operate the power source; wherein the processor is configured to intermittently power the primary coil.

12. The system of claim 9, further comprising a processor configured to operate the power source; wherein the processor is configured to continuously power the primary coil.

13. An apparatus for providing negative-pressure wound therapy, comprising: an absorptive dressing; a pump attached to the absorptive dressing and configured to provide negative pressure to the absorptive dressing; and a receiver portion of a two-part wireless power transmission device, configured to wirelessly receive power from an external source and direct the power to the pump.

14. The apparatus of claim 13, further comprising a pump actuator configured to activate the pump whenever negative pressure drops below a pre-set threshold; wherein the receiver portion comprises a receiver loop of an inductive power system.

15. A method for providing negative-pressure wound therapy to a tissue site, comprising: applying an absorptive negative -pressure dressing with an integral pump to the tissue site; and wirelessly providing power to the pump.

16. The method of claim 15, wherein wirelessly providing power further comprises aligning a transmitter coil and a receiver coil of an inductive power coupling system and inducing power in the receiver coil by energizing the transmitter coil.

17. The method of claim 16, further comprising monitoring alignment of the coils and activating an alarm when the coils are not aligned.

18. The method of claim 16, further comprising electrically coupling the receiver coil to the pump whenever negative pressure in the absorptive dressing falls below a pre-set threshold, and electrically uncoupling the receiver coil from the pump whenever the negative pressure in the absorptive dressing meets the pre-set threshold.

19. The method of claim 16, wherein wirelessly providing power further comprises continuously energizing the transmitter coil. 0. The method of claim 16, wherein wirelessly providing power further comprises energizing the transmitter coil when the negative pressure in the absorptive dressing falls below a pre-set threshold. 1. The system of claim 4, wherein the pump is in fluid communication with the manifold and the external environment, and is configured to provide negative pressure to the manifold. 2. The system of claim 1, wherein the absorptive dressing comprises an absorbent layer and a cover; the cover is configured to substantially prevent fluid flow therethrough and to be disposed over the absorbent layer and the pump; the cover further comprises a vent configured to fluidly couple the pump to an external environment through the cover; and the absorbent layer is configured for manifolding. 3. The system of claim 6, wherein the processor and the power source share a common housing external to the absorptive dressing. The system of claim 8, further comprising an alignment sensor configured to determine if the two portions of the wireless power transmission device are aligned. The system of claim 24, wherein the alignment sensor comprises a reed switch or magnetic sensor in the first portion of the wireless power transmission device and a magnet in the second portion of the wireless power transmission device. The system of claim 24, further comprising an alarm, wherein the processor is configured to activate the alarm when the two portions of the wireless power transmission device are not aligned or are located too far apart to effectively transmit power therebetween. The system of claim 10, wherein the pressure switch is biased towards a closed position, configured to actuate the pump, and is configured so that therapeutic negative pressure in the absorptive dressing overcomes the bias to an open position. The system of claim 27, wherein the pressure switch is biased by a bias element, and the bias element comprises a hysteresis dampener. The system of claim 11, wherein the processor is configured to periodically poll the primary coil to determine if pressure is being held. The system of claim 11, wherein the processor is configured to power the primary coil when the negative pressure in the absorbent dressing is below a pre-set threshold. The system of claim 30, wherein the processor is configured to determine when negative pressure is below the pre-set threshold by polling current drain at the primary coil. The system of claim 11, wherein the processor is configured to power the primary coil based on current dram at the primary coil. The system of claim 11, wherein the processor is configured to maintain power to the primary coil until a pre-set threshold has been met. The system of claim 33, wherein the processor is configured to determine if the pre-set threshold has been met based on current drain at the primary coil. The system of claim 1, wherein the absorptive dressing comprises superabsorbent material. The system of claim 1, wherein the absorptive dressing with integral pump may be pre-assembled as single unit. The system of claim 9, wherein the primary coil is attached to an exterior surface of the absorptive dressing by a light switchable adhesive. The system of claim 3, wherein the absorptive dressing comprises a cavity configured for the pump. The system of claim 1, wherein the pump is disposed on an external surface of the absorptive dressing. The apparatus of claim 14, wherein the pump actuator comprises a pressure switch configured to activate the pump when the negative pressure in the absorptive dressing less than pre-set level, and to deactivate the pump when the negative pressure in the absorptive dressing meets the pre-set level. 29 The apparatus of claim 13, further comprising a portion of an alignment sensor, configured to determine, in conjunction with another portion of the alignment sensor, if the two portions of the wireless power transmission device are aligned. The apparatus of claim 13, further comprising a transmitter portion of the wireless power transmission device removably attached to the exterior of the dressing. The method of claim 16, wherein wirelessly providing power further comprises energizing the transmitter coil based on current drain at the transmitter coil. The method of claim 18, further comprising determining whether negative pressure in the absorptive dressing is below the pre-set threshold based on current drain at the transmitter coil. The method of claim 16, further comprising removing the dressing from the tissue site, and disposing of the dressing. The method of claim 45, further comprising reusing the transmitter coil with another dressing having another pump and another receiver coil. The method of claim 18, wherein wirelessly providing power comprises polling the transmitter coil to determine if negative pressure in the dressing has fallen below the pre-set threshold. The method of claim 47, further comprising, upon determining that negative pressure in the dressing has fallen below the pre-set threshold, energizing the transmitter coil and maintaining energy to the transmitter coil until negative pressure in the dressing rises above the pre-set threshold. The method of claim 48, further comprising determining when to de-energize the transmitter coil based on current drain at the transmitter coil. The method of claim 49, further comprising re-polling the transmitter coil periodically. The method of claim 50, further comprising adjusting the frequency of polling the transmitter coil based on histoneal data. The systems, apparatuses, and methods, substantially as described herein.