Negative pressure wound therapy dressing with isolated superabsorbent

Abstract

A dressing for treating tissue using negative pressure may include a cover, an absorbent material, an isolation layer, and a manifold. The cover may have a first surface and a second surface opposite the first surface. The absorbent material may have a first surface adjacent to the second surface of the cover and a second surface opposite the first surface. The isolation layer may have a first surface adjacent to the second surface of the absorbent material and a second surface opposite the first surface. The isolation layer may be configured to restrict the flow of fluid from the tissue site to the absorbent material when negative pressure is applied to the dressing. The manifold may have a first surface adjacent to the second surface of the isolation layer and a second surface opposite the first surface.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 263,617, filed November 5, 2021, the entire contents of which are incorporated herein by reference.

[0002] The present invention, as described in the accompanying claims, relates generally to tissue treatment systems and, more particularly, but not exclusively, to negative pressure wound treatment dressings that include an isolation layer configured to limit the flow of fluid to an absorbent material during application of negative pressure. [Background technology]

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

[0004] While the clinical benefits of negative pressure therapy are widely known, improvements in therapy systems, components, and processes can benefit healthcare providers and patients. Summary of the Invention

[0005]

[0013] Novel and useful systems, devices, and methods for a dressing including an isolation layer in a negative pressure treatment environment are set forth in the accompanying claims. Example embodiments are also provided to enable those skilled in the art to make and use the claimed subject matter.

[0006] For example, in some exemplary embodiments, a dressing for treating a tissue site with negative pressure can include a cover, an absorbent material, an isolation layer, and a manifold. The cover can have a first surface and a second surface opposite the first surface. The absorbent material can have a first surface and a second surface opposite the first surface, and the first surface of the absorbent material can be adjacent to the second surface of the cover. The isolation layer can have a first surface and a second surface opposite the first surface, and the first surface of the isolation layer can be adjacent to the second surface of the absorbent material. The isolation layer can be configured to restrict the flow of fluid from the tissue site to the absorbent material when negative pressure is applied to the dressing. A manifold can have a first surface and a second surface opposite the first surface, and the first surface of the manifold can be adjacent to the second surface of the isolation layer.

[0007] More generally, the isolation layer can be disposed between the absorbent material and the manifold, the absorbent material can be encapsulated between the cover and the isolation layer, and the manifold can be disposed between the isolation layer and the tissue site.

[0008] In some exemplary embodiments, the isolation layer can include one or more valves configured to close when negative pressure is applied and open when negative pressure is removed. In other embodiments, the isolation layer can include a first layer having a plurality of valve flaps and a second layer having a plurality of holes configured to align with the plurality of valve flaps of the first layer. The plurality of holes of the second layer can be fluidly sealed by the plurality of valve flaps of the first layer when negative pressure is applied to the dressing. In other embodiments, the isolation layer can include a first layer of corrugated material having a first plurality of holes and a second layer having a second plurality of holes configured to be fluidly sealed by the first layer when negative pressure is applied to the dressing.

[0009] In some exemplary embodiments, the cover, absorbent material, and isolation layer can each include a negative pressure passage aligned with one another and configured to allow fluid communication between the manifold and a negative pressure source. The negative pressure passage can be in direct fluid communication with the manifold and can be fluidly isolated or sealed from the absorbent material. The negative pressure passage can be configured to receive a fluid connection that can include a negative pressure port positioned between the second surface of the absorbent material and the manifold. The fluid connection can fluidly isolate the negative pressure port from the absorbent material.

[0010] Systems for treating tissue sites are also described herein. Illustrative examples of the systems can include a dressing and a negative pressure source configured to be fluidly coupled to the dressing. The dressing can include a cover, an absorbent material, an isolation layer, and a manifold. The cover can have a first surface and a second surface opposite the first surface. The absorbent material can have a first surface and a second surface opposite the first surface, and the first surface of the absorbent material can be adjacent to the second surface of the cover. The isolation layer can have a first surface and a second surface opposite the first surface, and the first surface of the isolation layer can be adjacent to the second surface of the absorbent material. The isolation layer can be configured to restrict the flow of fluid from the tissue site to the absorbent material when negative pressure is applied to the dressing. A manifold can have a first surface and a second surface opposite the first surface, and the first surface of the manifold can be adjacent to the second surface of the isolation layer. In some embodiments, the system can also include a canister configured to be fluidly coupled between the dressing and the negative pressure source.

[0011] Another exemplary embodiment of a dressing for treating a site with negative pressure can include a cover, an absorbent material, an isolation layer, and a manifold. The cover can have a first surface and a second surface opposite the first surface. The absorbent material can have a first surface and a second surface opposite the first surface, and the first surface of the absorbent material can be adjacent to the second surface of the cover. The isolation layer can have a first surface and a second surface opposite the first surface, and the first surface of the isolation layer can be adjacent to the second surface of the absorbent material. The isolation layer can further include a valve flap in fluid communication with a negative pressure source and configured to open when negative pressure is applied to the dressing and close when the negative pressure is stopped. There can be a plurality of holes surrounding the valve flap in the isolation layer. A manifold can have a first surface and a second surface opposite the first surface, and the first surface of the manifold can be adjacent to the second surface of the isolation layer.

[0012] Other exemplary embodiments may include a dressing for treating a tissue site with negative pressure including an absorbent material, a manifold, and an isolation layer. The manifold layer may be configured to distribute negative pressure to the tissue site. The isolation layer may be disposed between the absorbent material and the manifold and configured to fluidly isolate the absorbent material from the manifold when negative pressure is applied to the manifold.

[0013] Methods of treating a tissue site are also described herein. An illustrative example of the method can include applying a dressing to the tissue site. The dressing can include an absorbent material and an isolation layer positioned between the absorbent material and the tissue site. The method can further include coupling a negative pressure source to a treatment space between the isolation layer and the tissue site such that the absorbent material is bypassed, and activating the negative pressure source to apply negative pressure to the treatment space. When activating the negative pressure source, one or more valves through the isolation layer are moved from an open state in which no negative pressure is applied to a closed state by operation in which negative pressure is applied. The method can further include deactivating the negative pressure source and collecting fluid from the tissue site with the absorbent material. The fluid can be configured to flow through the isolation layer to the absorbent material when the negative pressure source is deactivated and the one or more valves return to an open state.

[0014] The objects, advantages and preferred modes of making and using the claimed subject matter will be best understood by reference to the following detailed description of illustrative embodiments in conjunction with the accompanying drawings, in which: [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a block diagram of an exemplary embodiment of a treatment system capable of providing negative pressure treatment in accordance with the present disclosure. [Diagram 2] 2 is a cross-sectional view of an illustrative embodiment of the treatment system of FIG. 1 depicting an exemplary embodiment of a dressing interface and a dressing placed at a tissue site. [Diagram 3] FIG. 3 is a cross-sectional view of the dressing of FIG. [Figure 4] FIG. 4 is a detailed view of reference numeral 4 shown in FIG. 2, illustrating the exemplary dressing of FIG. 2 positioned adjacent tissue surrounding a tissue site. [Diagram 5] FIG. 5 is an exploded view of the dressing of FIG. 2 illustrating an exemplary embodiment of a release liner for protecting the dressing prior to application at a tissue site. [Figure 6] FIG. 6 is a plan view of an exemplary embodiment of the base layer shown in the dressing of FIG. [Figure 7A] FIG. 7A is a perspective view of an exemplary embodiment of an isolation layer depicted on the dressing of FIG. 5 when negative pressure is applied to the dressing and one or more valves associated with the isolation layer are closed. [Figure 7B] FIG. 7B is a perspective view of an exemplary embodiment of an isolation layer depicted in the dressing of FIG. 5 in a resting state when one or more valves are open. [Figure 7C] FIG. 7C is a cross-sectional view of the isolation layer of FIG. 7A illustrating that one or more holes through the isolation layer are closed by a valve. [Figure 7D] FIG. 7D is a cross-sectional view of the separator layer of FIG. 7B, illustrating the passageway through the pores in the separator layer when the valve is open. [Figure 8A] FIG. 8A is a cross-sectional view of the system illustrating an operational embodiment of the treatment system of FIG. 2 delivering negative pressure to a tissue site. [Figure 8B] FIG. 8B is a cross-sectional view of the system illustrating an operational embodiment of the system of FIG. 2 when negative pressure is not being delivered to the tissue site. [Figure 9A] FIG. 9A is a perspective view of another exemplary embodiment of an isolation layer that can be used with the dressing of FIG. 5, shown when negative pressure is applied to the dressing. [Figure 9B] FIG. 9B is a perspective view of an exemplary embodiment of the isolation layer of FIG. 9A in a quiescent state with no negative pressure applied. [Figure 9C]FIG. 9C is a cross-sectional view of the isolation layer of FIG. 9A showing multiple misaligned holes through the isolation layer that are sealed when negative pressure is applied. [Figure 9D] FIG. 9D is a cross-sectional view of the separator layer of FIG. 9B, illustrating the passageways through the pores of the separator layer when the negative pressure is removed. [Figure 10A] 10A is a perspective view of another exemplary embodiment of an isolation layer that can be used with the dressing of FIG. [Figure 10B] FIG. 10B is a cross-sectional view of the isolation layer of FIG. 10A. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The following description of exemplary embodiments provides information to enable one of ordinary skill in the art to make and use the subject matter recited in the appended claims, but may omit certain details already known in the art. Thus, the following detailed description is to be construed as illustrative and not limiting.

[0017] FIG. 1 is a block diagram of an exemplary embodiment of a treatment system 100 capable of providing negative pressure therapy to a tissue site in accordance with the present disclosure.

[0018] The term "tissue site" in this context broadly refers to a wound, defect, or other therapeutic target located on or within tissue, including, but not limited to, bone tissue, adipose tissue, muscle tissue, nerve tissue, dermal tissue, vascular tissue, connective tissue, cartilage, tendon, or ligament. Wounds may include, for example, chronic, acute, traumatic, subacute, and dehisced wounds, partial thickness burns, ulcers (such as diabetic ulcers, pressure ulcers, or venous insufficiency ulcers), skin flaps, and transplanted tissue. The term "tissue site" may also refer to any area of ​​tissue that is not necessarily wounded or defective, but instead to an area where it may be desirable to add or promote the growth of additional tissue. For example, negative pressure may be applied to the tissue site to grow additional tissue that may be harvested and transplanted.

[0019] Treatment system 100 may include a negative pressure source or supply, such as negative pressure source 105, and one or more distribution components. The distribution components are preferably removable and may be disposable, reusable, or recyclable. Dressings, such as dressing 110, and fluid containers, such as container 115, are examples of distribution components that may be associated with some examples of treatment system 100. As shown in the example of FIG. 1, dressing 110 may comprise or consist essentially of tissue interface 120, cover 125, or both in some embodiments.

[0020] A fluid conduit is another illustrative example of a distribution component. A "fluid conduit" in this context broadly includes a tube, pipe, hose, conduit, or other structure having one or more lumens or open pathways adapted to transport fluid between two ends. Typically, a tube is an elongated cylindrical structure with some flexibility, but the geometry and stiffness may vary. Also, some fluid conduits may be molded into or otherwise integrally combined with other components. A distribution component may also include or comprise an interface or fluid port to facilitate coupling and decoupling of other components. In some embodiments, for example, a dressing interface may facilitate coupling of a fluid conduit to a dressing 110. For example, such a dressing interface may be a SENSAT.RAC™ Pad available from Kinetic Concepts, Inc. (San Antonio, Texas).

[0021] The treatment system 100 may also include a controller, such as a regulator or controller 130. Additionally, the treatment system 100 may include sensors for measuring operating parameters and providing feedback signals indicative of the operating parameters to the controller 130. For example, as shown in FIG. 1, the treatment system 100 may include a first sensor 135 and a second sensor 140 coupled to the controller 130.

[0022] Some components of the treatment system 100 may be contained 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 and other components into a therapy unit 145.

[0023] In general, the components of the treatment system 100 may be directly or indirectly coupled. For example, the negative pressure source 105 may be directly coupled to the container 115 or indirectly coupled to the dressing 110 via the container 115. The coupling may include fluid coupling, mechanical coupling, thermal coupling, electrical coupling, or chemical coupling (such as chemical bonding), or in some contexts, some combination of couplings. For example, the negative pressure source 105 may be electrically coupled to the controller 130 and fluidly coupled to one or more distribution components to provide a fluid pathway to the tissue site. In some embodiments, the components may also be coupled by physical proximity, by being integrated into a single structure, or by being formed from the same piece of material.

[0024] A negative pressure source, such as the negative pressure source 105, may be a reservoir of air at negative pressure or may be a manual or powered device, such as, for example, a vacuum pump, a suction pump, a wall suction port available in many medical facilities, or a micropump. "Negative pressure" generally refers to a pressure that is less than the local ambient pressure, such as the ambient pressure in the local environment outside the sealed treatment environment. In many cases, the local ambient pressure may also be the atmospheric pressure where the tissue site is located. Alternatively, the pressure may be less than the hydrostatic pressure associated with the tissue at the tissue site. Unless otherwise indicated, the pressure values ​​described herein are gauge pressures. References to increasing negative pressure typically refer to decreasing absolute pressure, and decreasing negative pressure typically refers to increasing absolute pressure. The amount and nature of the negative pressure provided by the negative pressure source 105 may vary depending on the treatment requirements, but the pressure is generally a low vacuum, also commonly referred to as a rough vacuum, between -5 mmHg (-667 Pa) and -500 mmHg (-66.7 kPa). A typical therapeutic range is between -50mmHg (-6.7kPa) and -300mmHg (-39.9kPa).

[0025] Container 115 represents a container, canister, pouch, or other storage component that may be used to manage exudate and other fluids drawn from a tissue site. In many circumstances, a rigid container may be preferred or required for fluid collection, storage, and disposal. In other circumstances, fluids may be properly disposed of without being stored in a rigid container, and a reusable container may reduce waste and costs associated with negative pressure therapy.

[0026] A controller, such as controller 130, may be a microprocessor or computer programmed to operate one or more components of treatment system 100, such as negative pressure source 105. In some embodiments, for example, controller 130 may be a microcontroller, which generally comprises an integrated circuit including a processor core and memory programmed to directly or indirectly control one or more operating parameters of treatment system 100. The operating parameters may include, for example, the power applied to negative pressure source 105, the pressure generated by negative pressure source 105, or the pressure delivered to tissue interface 120. Controller 130 is also preferably configured to receive one or more input signals, such as feedback signals, and is programmed to modify one or more operating parameters based on the input signals.

[0027] Sensors, such as the first sensor 135 and the second sensor 140, can be any device operable to detect or measure a physical phenomenon or physical property and generally provide a signal indicative of the detected or measured phenomenon or property. For example, the first sensor 135 and the second sensor 140 can be configured to measure one or more operating parameters of the treatment system 100. In some embodiments, the first sensor 135 can be a transducer configured to measure the pressure in the air path and convert the measurement into a signal indicative of the measured pressure. In some embodiments, for example, the first sensor 135 can be a piezoresistive strain gauge. In some embodiments, the second sensor 140 can optionally measure an operating parameter of the negative pressure source 105, such as voltage or current. Preferably, the signals from the first sensor 135 and the second sensor 140 are suitable as input signals to the controller 130, although in some embodiments, some signal conditioning may be appropriate. For example, the signals may need to be filtered or amplified before the signals can be processed by the controller 130. Typically the signals are electrical signals, but may be represented in other forms, such as optical signals.

[0028] The tissue interface 120 may generally be adapted to partially or completely contact a tissue site. The tissue interface 120 may take many forms and may have many sizes, shapes, or thicknesses depending on various factors, such as the type of treatment being performed or the nature and size of the tissue site. For example, the size and shape of the tissue interface 120 may be adapted to the contours of a deep, irregularly shaped tissue site. Any or all of the surfaces of the tissue interface 120 may have an uneven, rough, or jagged profile.

[0029] In some embodiments, tissue interface 120 may comprise or consist essentially of a manifold. A manifold in this context may comprise or consist essentially of a means for collecting or distributing fluid across tissue interface 120 under pressure. For example, the manifold may be adapted to receive negative pressure from a source and distribute the negative pressure across tissue interface 120 via a plurality of openings, which may have the effect of collecting fluid across the tissue site and drawing the fluid towards the source. In some embodiments, the fluid path may be reversed or a secondary fluid path may be provided to facilitate delivery of fluid across the tissue site.

[0030] In some exemplary embodiments, the manifold may comprise multiple passages that may be interconnected to improve fluid distribution or collection. In some exemplary embodiments, the manifold may comprise or consist essentially of a porous material having interconnected fluid pathways. Examples of suitable porous materials that may be adapted to form interconnected fluid pathways (e.g., channels) may include cellular foams, including open-cell foams such as reticulated foams, porous tissue masses, and other porous materials such as gauze or felt mats that generally include pores, edges, and / or walls. Liquids, gels, and other foams may also include or harden to include openings and fluid pathways. In some embodiments, the manifold may additionally or alternatively comprise protrusions that form interconnected fluid pathways. For example, the manifold may be molded to provide surface protrusions that define interconnected fluid pathways.

[0031] In some embodiments, the tissue interface 120 may comprise or consist essentially of a reticulated foam with pore size and free volume that may vary according to the needs of a given treatment. For example, a reticulated foam with at least 90% free volume may be suitable for many treatment applications, and a foam with an average pore size in the range of 400-600 micrometers (40-50 pores per inch) may be particularly suitable for some types of treatment. The tensile strength of the tissue interface 120 may also vary according to the prescribed needs of the treatment. The 25% compressive load deflection of the tissue interface 120 may be at least 0.35 pounds per square inch, and the 65% compressive 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 a foam composed of a polyol, such as a polyester or polyether, an isocyanate, such as toluene diisocyanate, and a polymerization modifier, such as an amine or tin compound. In some examples, the tissue interface 120 may be a reticulated polyurethane foam, such as found in GRANUFOAM™ dressings or VACVERAFLO™ dressings, both available from Kinetic Concepts, Inc. of San Antonio, Texas.

[0032] The thickness of the tissue interface 120 may also vary depending on the needs of the prescribed treatment. For example, the thickness of the tissue interface may be reduced to reduce tension on peripheral tissues. The thickness of the tissue interface 120 may also affect the conformability of the tissue interface 120. In some embodiments, a thickness in the range of about 5 millimeters to 10 millimeters may be suitable.

[0033] The tissue interface 120 can be either hydrophobic or hydrophilic. In instances where the tissue interface 120 may be hydrophilic, the tissue interface 120 may also wick fluid away from the 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 the tissue site by capillary flow or other wicking mechanisms. One example of a hydrophilic material that may be suitable is an open-cell foam of polyvinyl alcohol, such as VACWHITEFOAM™ dressing available from Kinetic Concepts, Inc. (San Antonio, Texas). Other hydrophilic foams may include those made from polyethers. Other foams that may exhibit hydrophilic characteristics include hydrophobic foams that have been treated or coated to impart hydrophilicity.

[0034] In some embodiments, the tissue interface 120 may be constructed from a bioabsorbable material. Suitable bioabsorbable materials may include, but are not limited to, a polymer blend of polylactic acid (PLA) and polyglycolic acid (PGA). Polymer blends may also include, but are not limited to, polycarbonate, polyfumarate, and capralactone. The tissue interface 120 may further function 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 cell growth or tissue formation, such as a three-dimensional porous structure that provides a template for cell growth. Illustrative examples of scaffold materials include calcium phosphate, collagen, PLA / PGA, coral hydroxyapatite, carbonate, or engineered allograft materials.

[0035] In some embodiments, the cover 125 may provide a barrier against bacteria and protection from physical trauma. The cover 125 may also be constructed from a material that can reduce evaporative loss and provide a fluid seal between two components or two environments, such as a fluid seal between a therapy environment and a local external environment. The cover 125 may include or consist of, for example, an elastomeric film or membrane that can provide a suitable seal to maintain the negative pressure of a given negative pressure source at the tissue site. 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 24 hours as measured using the Upright Cup Method of ASTM E96 / E96M at 38° C. and 10% relative humidity (RH). In some embodiments, an MVTR of up to 5,000 grams per square meter per 24 hours may provide effective breathability and mechanical properties.

[0036] In some exemplary embodiments, the cover 125 may be a polymer drape, such as a polyurethane film, that is permeable to water vapor but impermeable to liquids. Such drapes typically have a thickness in the range of 25-50 micrometers. For permeable materials, the permeability should generally be low enough to maintain the desired negative pressure. The cover 125 may include, for example, one or more of the following materials: polyurethanes (PU), such as hydrophilic polyurethanes; cellulose derivatives; hydrophilic polyamides; polyvinyl alcohols; polyvinylpyrrolidones; hydrophilic acrylics; silicones, such as hydrophilic silicone elastomers; natural rubber; polyisoprene; styrene butadiene rubber; chloroprene rubber; polybutadiene; nitrile rubber; butyl rubber; ethylene propylene rubber; ethylene propylene diene monomer; chlorosulfonated polyethylene; polysulfide rubber; ethylene vinyl acetate (EVA); copolyesters; and polyether block polyimide copolymers. Such materials are commercially available, for example, Tegaderm® drapes available from 3M Company, Minneapolis, Minnesota, polyurethane (PU) drapes available from Avery Dennison Corporation, Pasadena, California, such as polyether block polyamide copolymer (PEBAX) from Arkema SA, Colombes, France, and Inpsire 2301 and Inspire 2327 polyurethane films available from Expopack Advanced Coatings, Wrexham, United Kingdom. In some embodiments, the cover 125 has a thickness of 2600 g / m 2 / INSPIRE2301 having a 24 hour MVTR (upright cup method) and a thickness of approximately 30 micrometers.

[0037] The attachment device may be used to attach the cover 125 to a mounting surface, such as an intact epidermis, a gasket, or another cover. The attachment device may take many forms. For example, the attachment device may be a medically acceptable pressure sensitive adhesive configured to bond the cover 125 to the epidermis around the 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 to 65 grams per square meter (gsm). In some embodiments, a thicker adhesive, or combination of adhesives, may be applied to improve the seal and reduce leakage. Other exemplary embodiments of the attachment device may include double-sided tape, glue, hydrocolloid, hydrogel, silicone gel, or organogel.

[0038] In operation, the tissue interface 120 may be disposed within, on, over, or otherwise proximate to the tissue site. For example, if the tissue site is a wound, the tissue interface 120 may partially or completely occlude or be disposed over the wound. The cover 125 may be disposed over the tissue interface 120 and sealed to an attachment surface near the tissue site. For example, the cover 125 may be sealed to the intact epidermis surrounding the tissue site. Thus, the dressing 110 may provide a sealed treatment environment proximate the tissue site that is substantially isolated from the external environment, and the negative pressure source 105 may reduce pressure within the sealed treatment environment.

[0039] The process of reducing pressure can be described herein as, for example, "delivering," "distributing," or "generating" negative pressure. Generally, exudate and other fluids flow along a fluid pathway toward a lower pressure. Thus, the term "downstream" typically refers to a location in the fluid pathway that is relatively closer to a negative pressure source or farther away from a positive pressure source. Conversely, the term "upstream" refers to a location that is relatively farther away from a negative pressure source or closer to a positive pressure source. However, the fluid pathway may also be reversed in some applications, such as by replacing a negative pressure source with a positive pressure source, and these descriptive terms should not be construed as limiting.

[0040] In a sealed treatment environment, negative pressure applied to the tissue site through tissue interface 120 can induce macro- and microstrains in the tissue site. The negative pressure can also remove exudate and other fluids from the tissue site, which can be collected in container 115.

[0041] In some embodiments, the controller 130 can receive and process data from one or more sensors, such as the first sensor 135. The controller 130 can also control the operation of one or more components of the treatment system 100 to manage the pressure delivered to the tissue interface 120. In some embodiments, the controller 130 can include an input for receiving a desired target pressure and can be programmed to process data regarding the setting and input of the target pressure to be applied to the tissue interface 120. In some exemplary embodiments, the target pressure can be a fixed pressure value, which is set by an operator as the target negative pressure desired for treatment at the tissue site and then provided as an input to the controller 130. The target pressure can vary from tissue site to tissue site based on the type of tissue forming the tissue site, the type of injury or wound (if any), the health of the patient, and the preferences of the attending physician. After selection of the 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 can receive feedback from one or more sensors to maintain the target pressure at the tissue interface 120.

[0042] 2 illustrates an exemplary embodiment of a treatment system 100 for treating a tissue site 202 of a patient. The tissue site 202 may extend through or involve the epidermis 204, the dermis 206, and the subcutaneous tissue 208. The tissue site 202 may be a subsurface tissue site as shown in FIG. 2 that extends below the surface of the epidermis 204. Additionally, the tissue site 202 may be a superficial tissue site (not shown) that resides primarily on the surface of the epidermis 204, such as, for example, an incision. The treatment system 100 may provide treatment to, for example, the epidermis 204, the dermis 206, and the subcutaneous tissue 208, regardless of the positioning of the treatment system 100 or the type of tissue site. The treatment system 100 may also be used at other tissue sites, without limitation.

[0043] Furthermore, tissue site 202 may be any human, animal, or other organism's body tissue, including bone tissue, adipose tissue, muscle tissue, dermal tissue, vascular tissue, connective tissue, cartilage tissue, tendons, ligaments, or any other tissue. Treatment of tissue site 202 may include removal of fluid, such as exudate or peritoneal fluid.

[0044] 2 , the treatment system 100 may include the dressing 110, the container 115, and the treatment unit 145, which may include the negative pressure source 105. Additionally, the treatment system 100 may include a filler material 214 as an optional component of the treatment system 100, which may be omitted for different types of tissue sites or different types of treatments using negative pressure, such as epithelialization. If provided, the filler material 214 may be adapted to be positioned proximate or adjacent to the tissue site 202, such as by cutting or shaping the filler material 214 in any suitable manner to fit the tissue site 202 and fill the space between the tissue site 202 and the dressing 110. Similar to the tissue interface 120, the filler material 214 may be constructed from a manifold material described herein and may be adapted to be positioned in fluid communication with the tissue site 202 and distribute negative pressure to the tissue site 202. In some embodiments, the filler material 214 may be positioned in direct contact with the tissue site 202, between the tissue site 202 and the dressing 110. If the filler material 214 is omitted, the tissue interface 120 of the dressing 110 may be positioned in direct contact with the tissue site 202.

[0045] 2, the dressing 110 may be adapted to provide or distribute negative pressure from the negative pressure source 105 of the treatment unit 145 to the tissue site 202, either directly or through a filler material 214 (if equipped). Additionally, FIG. 2 illustrates additional features that may be associated with some exemplary embodiments of the tissue interface 120 of the dressing 110. For example, the tissue interface 120 of the dressing 110 may include an optional base layer 218, a manifold 220, an isolation layer 222, and an absorbent material 224. An adhesive layer, such as adhesive 226, may be configured to be disposed between the cover 125 and the periphery of the tissue site 202 to secure the dressing 110 to the tissue site 202. Components of the dressing 110 may be added or removed to suit a particular application.

[0046] 2-6, the base layer 218 may have a perimeter 230 surrounding a central portion 232 and a plurality of openings 234 disposed through the perimeter 230 and the central portion 232. The base layer 218 may also have corners 236 and edges 238. The corners 236 and the edges 238 may be part of the perimeter 230. One of the edges 238 may meet with another of the edges 238 to define one of the corners 236. Additionally, the base layer 218 may have a boundary 240, the boundary 240 substantially surrounding the central portion 232 and positioned between the central portion 232 and the perimeter 230. The boundary 240 may not include the openings 234. The base layer 218 may cover the tissue site 202 and the tissue surrounding the tissue site 202 such that a central portion 232 of the base layer 218 is positioned adjacent or proximate to the tissue site 202 and a peripheral portion 230 of the base layer 218 is positioned adjacent or proximate to the tissue surrounding the tissue site 202. In this manner, the peripheral portion 230 of the base layer 218 may surround the tissue site 202. Additionally, the openings 234 in the base layer 218 may be in fluid communication with the tissue site 202 and the tissue surrounding the tissue site 202.

[0047] The openings 234 in the base layer 218 may have any shape, such as, for example, a circle, a square, a star, an oval, a polygon, a slit, a complex curve, a linear shape, a triangle, or other shape. The openings 234 may be formed by cutting, by application of localized RF energy, or by other suitable techniques for forming an opening. As shown in FIGS. 4-6, each opening 234 of the plurality of openings 234 may be substantially circular in shape having a diameter and an area. The area of ​​each opening 234 may refer to the open space or open area that defines each opening 234. The diameter of each opening 234 may define the area of ​​each opening 234. For example, the area of ​​one of the openings 234 may be defined by multiplying half the diameter of the opening 234 by the value 3.14. Thus, the following equation: Area=3.14 * (Diameter / 2)^2 may define the area of ​​one of the apertures 234. The areas of the apertures 234 described in the exemplary embodiments herein may be substantially similar to the areas of other embodiments of the apertures 234 (not shown), which may have non-circular shapes. The diameter of each aperture 234 may be substantially the same, or each diameter may vary, for example, depending on the location of the aperture 234 within the base layer 218. For example, the diameter of the apertures 234 within the periphery 230 of the base layer 218 may be larger than the diameter of the apertures 234 within the central portion 232 of the base layer 218. Furthermore, the diameter of each aperture 234 may be from about 1 millimeter to about 50 millimeters. In some embodiments, the diameter of each aperture 234 may be from about 1 millimeter to about 20 millimeters. The apertures 234 may have a uniform pattern or may be randomly distributed on the base layer 218. The size and configuration of the apertures 234 may be designed to control the adhesion of the dressing 110 to the epidermis 204, as described below.

[0048] 5 and 6, in some embodiments, the openings 234 located at the periphery 230 may be openings 234a, the openings 234 located at the corners 236 of the periphery 230 may be openings 234b, and the openings 234 located at the central portion 232 may be openings 234c. The openings 234a may have a diameter of about 9.8 millimeters to about 10.2 millimeters. The openings 234b may have a diameter of about 7.75 millimeters to about 8.75 millimeters. The openings 234c may have a diameter of about 1.8 millimeters to about 2.2 millimeters. The diameters of each of the openings 234a may be separated from each other by a distance A of about 2.8 millimeters to about 3.2 millimeters. Furthermore, the diameter of at least one of the openings 234a may be separated from the diameter of at least one of the openings 234b by the distance A. The diameters of each of the openings 234b may also be separated from each other by the distance A. The center of one of the apertures 234c may be separated from the center of another of the apertures 234c in a first direction by a distance B of about 2.8 millimeters to about 3.2 millimeters. In a second direction transverse to the first direction, the center of one of the apertures 234c may be separated from the center of another of the apertures 234c by a distance C of about 2.8 millimeters to about 3.2 millimeters. As shown in Figures 5 and 6, the distance B and the distance C may be increased for apertures 234c of the central portion 232 located near or at the boundary 240 compared to apertures 234c located away from the boundary 240.

[0049] As shown in FIGS. 5-6, the central portion 232 of the base layer 218 may be substantially square with each side of the central portion 232 having a length D of about 100 millimeters to about 108 millimeters. In some embodiments, the length D may be about 106 millimeters to about 108 millimeters. The boundary 240 of the base layer 218 may have a width E between about 4 millimeters to about 11 millimeters and may substantially surround the central portion 232 and the opening 234c within the central portion 232. In some embodiments, the width E may be about 9 millimeters to about 10 millimeters. The peripheral portion 230 of the base layer 218 may have a width F between about 25 millimeters to about 35 millimeters and may substantially surround the boundary 240 and the central portion 232. In some embodiments, the width F may be about 26 millimeters to about 28 millimeters. Additionally, the peripheral portion 230 may have a substantially square exterior with each outer side having a length G of about 154 millimeters to about 200 millimeters. In some embodiments, the length G may be from about 176 millimeters to about 184 millimeters. Although the central portion 232, the border 240, and the periphery 230 of the base layer 218 are shown in FIGS. 5-6 as having a substantially square shape, these and other components of the base layer 218 may have any shape to suit a particular application. Additionally, the dimensions of the base layer 218 as described herein may be increased or decreased, for example, substantially in proportion to one another, to suit a particular application. Using dimensions in the above ratios may improve the appearance of the tissue site. For example, these ratios may provide a surface area for the base layer 218, regardless of shape, that is sufficiently smooth to enhance epithelial cell migration and proliferation at the tissue site 202 and reduce the likelihood of ingrowth of granulation tissue into the dressing 110.

[0050] The base layer 218 may be a soft and pliable material suitable for providing a fluid seal with the tissue site 202 as described herein. For example, the base layer 218 may include silicone gel, soft silicone, hydrocolloid, hydrogel, polyurethane gel, polyolefin gel, hydrogenated styrene copolymer gel, foam gel, soft closed cell foam such as polyurethane and polyolefin coated with adhesives as described below, polyurethane, polyolefin, or hydrogenated styrene copolymer. The base layer 218 may have a thickness of about 500 microns (μm) to about 1000 microns (μm). In some embodiments, the base layer 218 has a stiffness of about 5 Shore OO to about 80 Shore OO. The base layer 218 may be comprised of a hydrophobic or hydrophilic material.

[0051] In some embodiments (not shown), the base layer 218 can be a coated hydrophobic material. For example, the base layer 218 can be formed by coating a porous material, such as, for example, a woven mesh, a nonwoven mesh, a molded mesh, or an extruded mesh, with a hydrophobic material. The coating hydrophobic material can be, for example, a soft silicone. In this manner, the adhesive 226 can extend through openings in the porous material, similar to the openings 234 described below.

[0052] The adhesive 226 may be in fluid communication with the openings 234 in at least the periphery 230 of the base layer 218. In this manner, the adhesive 226 may be in fluid communication with the tissue surrounding the tissue site 202 through the openings 234 in the base layer 218. As described below and shown in FIG. 4 , the adhesive 226 may extend or be forced through the multiple openings 234 to contact the epidermis 204, for example, to secure the dressing 110 to the tissue surrounding the tissue site 202. The openings 234 may provide sufficient contact of the adhesive 226 to the epidermis 204 to secure the dressing 110 about the tissue site 202. However, the configuration of the openings 234 and adhesive 226 described below may allow for release and repositioning of the dressing 110 about the tissue site 202.

[0053] At least one of the openings 234a in the periphery 230 of the base layer 218 may be positioned at an edge 238 of the periphery 230 and may have an internal cut that is open or exposed at the edge 238 and in lateral fluid communication with the edge 238. The lateral direction may refer to a direction toward the edge 238 and in the same plane as the base layer 218. As shown in FIGS. 5-6, the multiple openings 234a in the periphery 230 may be positioned proximate or at the edge 238 and in lateral fluid communication with the edge 238. The openings 234a positioned proximate or at the edge 238 may be spaced substantially equidistantly around the periphery 230 as shown in FIGS. 5-6. However, in some embodiments, the spacing of the openings 234a proximate or at the edge 238 may be irregular. The adhesive 226 may be in fluid communication with the edge 238 through the openings 234a exposed at the edge 238. In this manner, the openings 234a at the edge 238 may allow the adhesive 226 to flow around the edge 238 to improve adhesion of the edge 238 around the tissue site 202, for example.

[0054] With continued reference to FIGS. 5-6, the openings 234b at the corners 236 of the periphery 230 may be smaller than the openings 234a at other portions of the periphery 230, as described above. For a given geometric shape of the corners 236, the smaller size of the openings 234b compared to the openings 234a may maximize the surface area of ​​the adhesive 226 exposed and in fluid communication through the openings 234b at the corners 236. For example, as shown in FIGS. 5-6, the edges 238 may intersect at a substantially right angle or about 90 degrees to define the corners 236. Also as shown, the corners 236 may have a radius of about 10 millimeters. Three of the openings 234b, having diameters of about 7.75 millimeters to about 8.75 millimeters, may be positioned in a triangular configuration at the corners 236 to maximize the exposed surface area of ​​the adhesive 226. As discussed above, the size and number of the openings 234b in the corners 236 may be adjusted as needed depending on the selected geometry of the corners 236 to maximize the exposed surface area of ​​the adhesive 226. Additionally, the openings 234b in the corners 236 may be fully contained within the base layer 218 to substantially eliminate lateral fluid communication to the outside of the corners 236. By having the openings 234b in the corners 236 fully contained within the base layer 218, fluid communication of the adhesive 226 to the outside of the corners 236 may be substantially eliminated to improve handling of the dressing 110 during placement at the tissue site 202. Additionally, by having the outside of the corners 236 be substantially free of adhesive 226, the flexibility of the corners 236 may be improved to enhance comfort.

[0055] As with the openings 234b at the corners 236, the size and number of any of the openings 234 may be adjusted to maximize the surface area of ​​the adhesive 226 in fluid communication through the openings 234 depending on the particular application or geometry of the base layer 218. For example, in some embodiments (not shown), the openings 234b, or openings of another size, may be located at the perimeter 230 and at the border 240. Similarly, the openings 234b, or openings of another size, may be located as described above in other locations on the base layer 218 that may have complex geometries or shapes.

[0056] The adhesive 226 may be a medically acceptable adhesive. The adhesive 226 may also be flowable. For example, the adhesive 226 may include an acrylic adhesive, a rubber adhesive, a high tack silicone adhesive, a polyurethane, or other adhesive substance. In some embodiments, the adhesive 226 has a viscosity of 15 grams / m 2 (gsm) ~70 grams / m 2 The adhesive 226 may be a pressure sensitive adhesive including an acrylic adhesive having a coating weight of 100 gsm. The adhesive 226 may be a layer having substantially the same shape as the periphery 230 of the base layer 218, as shown in FIG. 5. In some embodiments, the layer of adhesive 226 may be continuous or discontinuous. The discontinuities in the adhesive 226 may be provided by openings (not shown) in the adhesive 226. The openings in the adhesive 226 may be formed after application of the adhesive 226 or on the carrier layer, for example, by coating the adhesive 226 in a pattern on the side of the cover 125 adapted to face the epidermis 204. Additionally, the openings in the adhesive 226 may be sized to control the amount of adhesive 226 that extends through the openings 234 in the base layer 218 to reach the epidermis 204. The openings in the adhesive 226 may also be sized to improve the Moisture Vapor Transfer Rate (MVTR) of the dressing 110.

[0057] Factors that may be used to control the adhesive strength of the dressing 110 may include the diameter and number of openings 234 in the base layer 218, the thickness of the base layer 218, the thickness and amount of adhesive 226, and the adhesive's 226 viscosity. An increase in the amount of adhesive 226 extending through the openings 234 generally corresponds to an increase in the adhesive strength of the dressing 110. A decrease in the thickness of the base layer 218 generally corresponds to an increase in the amount of adhesive 226 extending through the openings 234. Thus, the diameter and configuration of the openings 234, the thickness of the base layer 218, and the amount and viscosity of adhesive used may be varied to provide a desired adhesive strength of the dressing 110. For example, the base layer 218 may be approximately 200 micrometers thick, the layer of adhesive 226 may have a thickness of approximately 30 micrometers and a viscosity of 2000 grams per 25 centimeter wide strip, and the diameter of the openings 234a in the base layer 218 may be approximately 10 millimeters.

[0058] In some embodiments, the tackiness of the adhesive 226 may vary at different locations within the base layer 218. For example, in locations within the base layer 218 where the openings 234 are relatively larger, such as opening 234a, the adhesive 226 may have a lower tackiness than other locations within the base layer 218 where the openings 234 are smaller, such as openings 234b and opening 234c. In this manner, locations within the base layer 218 having larger openings 234 and less tacky adhesive 226 may have adhesive strength comparable to locations having smaller openings 234 and more tacky adhesive 226.

[0059] Clinical studies have shown that the configurations described herein for the base layer 218 and adhesive 226 may reduce the occurrence of blistering, erythema, and leakage during use. Such configurations may provide, for example, increased patient comfort and increased durability of the dressing 110.

[0060] With reference to the embodiment of FIG. 5, the release liner 242 may be attached to or positioned adjacent to the base layer 218 to protect the adhesive 226 prior to application of the dressing 110 to the tissue site 202. Prior to application of the dressing 110 to the tissue site 202, the base layer 218 may be positioned between the cover 125 and the release liner 242. Removal of the release liner 242 may expose the base layer 218 and adhesive 226 for application of the dressing 110 to the tissue site 202. The release liner 242 may also provide rigidity to aid in placement of the dressing 110, for example. The release liner 242 may be, for example, cast paper, film, or polyethylene. Additionally, the release liner 242 may be a polyester material, such as polyethylene terephthalate (PET) or a similar polar semi-crystalline polymer. The use of a polar semi-crystalline polymer for the release liner 242 may substantially prevent wrinkling or other deformation of the dressing 110. For example, polar semi-crystalline polymers may be highly oriented and resistant to softening, swelling, or other deformations that may occur when in contact with components of the dressing 110 or when subjected to temperature changes, environmental changes, or sterilization. Additionally, a release agent may be disposed on the side of the release liner 242 configured to contact the base layer 218. For example, the release agent may be a silicone coating and may have suitable release factors to facilitate removal of the release liner 242 manually and without damaging or deforming the dressing 110. In some embodiments, the release agent may be a fluorosilicone. In other embodiments, the release liner 242 may be uncoated or otherwise used without a release agent.

[0061] 2-6, the cover 125 may be substantially similar to that described above with reference to FIG. 1. The cover 125 may have an edge or perimeter 244 and a central portion 246. The cover 125 may also have a first surface 248 and a second surface 250 opposite the first surface 248. The cover 125 may further include an aperture 252. The aperture 252 may be an opening or hole through the cover 125. In some embodiments, the aperture 252 may be substantially located in the center of the cover 125. The aperture 252 may be configured to allow fluid communication from the first surface 248 of the cover 125 through the dressing 110. The peripheral portion 244 of the cover 125 may be positioned proximate to the peripheral portion 230 of the base layer 218 such that the central portion 246 of the cover 125 and the central portion 232 of the base layer 218 define an enclosure 254.

[0062] The adhesive 226 may be positioned at least between the perimeter 244 of the cover 125 and the perimeter 230 of the base layer 218. The cover 125 may cover the tissue site 202 and the tissue interface 120 to provide a fluid seal and a sealed space 256 between the tissue site 202 and the cover 125 of the dressing 110. Additionally, the cover 125 may cover other tissue, such as a portion of the epidermis 204 surrounding the tissue site 202, to provide a fluid seal between the cover 125 and the tissue site 202. In some embodiments, a portion of the perimeter 244 of the cover 125 may extend beyond the perimeter 230 of the base layer 218 and directly contact the tissue surrounding the tissue site 202. In other embodiments, the perimeter 244 of the cover 125 may be positioned in contact with the tissue surrounding the tissue site 202, for example, to provide a sealed space 256 without the base layer 218. Thus, the adhesive 226 may also be positioned at least between the periphery 244 of the cover 125 and tissue, such as the epidermis 204, surrounding the tissue site 202. The adhesive 226 may be disposed on a surface of the cover 125 adapted to face the tissue site 202 and the base layer 218.

[0063] The absorbent material 224, the isolation layer 222, and the manifold 220 may be disposed within the enclosure 254, the sealed space 256, or both. The isolation layer 222 may be positioned between the absorbent material 224 and the manifold 220, the absorbent material 224 may be encapsulated between the cover 125 and the isolation layer 222, and the manifold 220 may be positioned between the isolation layer 222 and the tissue site 202 and, if provided, the base layer 218.

[0064] The absorbent material 224 may be superabsorbent and may have a first surface 258 and a second surface 260 opposite the first surface 258. The absorbent material 224 may further include an opening 261 configured to align with the opening 252 of the cover 125. The first surface 258 of the absorbent material 224 may be adjacent to the second surface 250 of the cover 125. In some embodiments, the absorbent material 224 is isolated from the manifold 220 and the tissue site 202 when negative pressure is applied to the tissue site 202. When negative pressure is not applied to the tissue site 202, the absorbent material 224 may be in fluid communication with the manifold 220 and the tissue site 202 through the isolation layer 222. The absorbent material 224 may be configured to absorb fluid from the tissue site 202 when the absorbent material 224 is in fluid communication with the manifold 220 and the tissue site 202 through the isolation layer 222. Suitable materials for the absorbent material can include Luquafleece® material, Texas FP2326, BASF 402C, Technical Absorbents 2317 available from Technical Absorbents (www.techabsorbents.com), sodium polyacrylate superabsorbents, cellulose derivatives (carboxymethylcellulose and salts such as sodium CMC), or alginates.

[0065] The isolation layer 222 may be disposed between the absorbent material 224 and the manifold 220. The isolation layer 222 may have a first surface 262 and a second surface 264 opposite the first surface 262. The first surface 262 of the isolation layer 222 may be adjacent to the second surface 260 of the absorbent material 224. The isolation layer 222 may further include an opening 265. The opening 265 may be aligned with, but smaller than, the opening 261 of the absorbent material 224. The isolation layer 222 may be configured to restrict the flow of fluid from the tissue site 202 to the absorbent material 224 when negative pressure is applied to the dressing 110.

[0066] With continued reference to FIGS. 2, 3, 5, and 7A-7D, the isolation layer 222 can include a first layer 266 and a second layer 268. The first layer 266 can include a plurality of valve flaps 270 and the second layer can include a plurality of holes 272. The plurality of holes 272 of the second layer 268 can be aligned with the plurality of valve flaps 270 of the first layer 266. With reference to FIG. 7C, the plurality of valve flaps 270 can be configured to close when negative pressure is applied to the dressing 110. When closed, the plurality of valve flaps 270 can fluidly seal the plurality of holes 272 of the second layer 268. With reference to FIG. 7D, the plurality of valve flaps 270 can be configured to move away from the plurality of holes 272 when negative pressure is not applied to the dressing 110 to provide a passageway 271 through the isolation layer 222. The plurality of valve flaps 270 can be configured to allow fluid flow in a first direction from the second surface 264 of the isolation layer 222 toward the first surface 262 of the isolation layer 222 when negative pressure is not applied to the dressing 110. The plurality of valve flaps 270 can prevent fluid flow in a second direction from the first surface 262 of the isolation layer 222 toward the second surface 264 of the isolation layer 222. When negative pressure is applied to the dressing 110, the plurality of valve flaps 270 may prevent fluid flow in all directions, e.g., both the first direction and the second direction. In other embodiments, the isolation layer 222 may be only one layer that may include the plurality of valve flaps 270 configured to close when negative pressure is applied to the dressing 110 and configured to open to provide a passageway through the isolation layer 222 when negative pressure is not applied to the dressing.

[0067] The first layer 266 of the isolation layer 222 can have a first surface, which can be the first surface 262 of the isolation layer 222. The first layer 266 of the isolation layer 222 can have a second surface 274 opposite the first surface 262. The plurality of valve flaps 270 may be configured to open from the second surface 274 of the first layer 266 toward the first surface 262 of the isolation layer 222. The first layer 266 of the isolation layer 222 can be sufficiently thick to allow the plurality of valve flaps 270 to open and expose the plurality of holes 272 in the second layer 268 without any portion of the plurality of valve flaps 270 contacting the absorbent material 224.

[0068] The plurality of valve flaps 270 of the isolation layer 222 may be check valves in some embodiments. Exemplary check valves may include ball check valves, diaphragm check valves, flap check valves, swing check valves, stop-check valves, duckbill valves, pneumatic check valves, or other one-way valves configured to automatically allow fluid flow in a single direction and prevent fluid flow in any other direction.

[0069] In some embodiments, there may be at least one spacer or protrusion disposed between the isolation layer 222 and the absorbent material 224. The at least one spacer or protrusion may be positioned around or adjacent to one or more of the valve flaps 270 and may be configured in any suitable manner to provide a pathway or additional space between the isolation layer 222 and the absorbent material 224. The pathway may ensure that the multiple valve flaps 270 have sufficient space to open to expose the multiple holes 272 in the second layer 268 of the isolation layer 222 when the negative pressure source 105 is stopped.

[0070] Both the first layer 266 and the second layer 268 of the isolation layer 222 may be composed of a liquid impermeable film. In some embodiments, the first layer 266 and the second layer 268 of the isolation layer 222 may comprise one or more of the following materials: hydrophilic polyurethane, cellulose derivatives, hydrophilic polyamide, polyvinyl alcohol, polyvinylpyrrolidone, hydrophilic acrylic, hydrophilic silicone elastomer, such as 14400 g / m 2 INSPIRE 2301 material from Expopack Advanced Coatings (Wrexham, United Kingdom) having a MVTR (inverted cup technology) of 1 / 24 hours and a thickness of about 30 microns, uncoated thin polymer drapes, natural rubber, polyisoprene, styrene butadiene rubber, chloroprene rubber, polybutadiene, nitrile rubber, butyl rubber, ethylene propylene rubber, ethylene propylene diene monomer, chlorosulfonated polyethylene, polysulfide rubber, polyurethane (PU), EVA film, copolyester, silicone, silicone drapes, 3M Tegaderm® drapes, polyurethane (PU) drapes such as those available from Avery Dennison Corporation (Pasadena, California), e.g., polyether block polyamide copolymer (PEBAX) from Arkema (France), Expopack 2327, or other suitable materials.

[0071] In some embodiments, the first layer 266 and the second layer 268 of the isolation layer 222 have a compressibility of, for example, at least about 300 g / m per 24 hours. 2 In other embodiments, a low vapor transmission drape or a vapor impermeable drape may be used. The first layer 266 and the second layer 268 of the isolation layer 222 may include a range of medically suitable films having a thickness between about 15 microns (μm) and about 50 microns (μm). In other embodiments, the first layer 266 and the second layer 268 of the isolation layer 222 may be a non-breathable film, membrane, or sheet that may be substantially vapor and liquid impermeable.

[0072] 2, 3, and 5, the manifold 220 can have a first surface 276 and a second surface 278 opposite the first surface 276. The manifold 220 can comprise, or consist essentially of, a means for distributing fluid to the tissue site 202. For example, the manifold 220 can be adapted to receive negative pressure from the negative pressure source 105 and distribute the negative pressure across or through the manifold 220 via a plurality of apertures, which can have the effect of collecting fluid from the tissue site 202 and drawing the fluid towards the negative pressure source 105.

[0073] In some exemplary embodiments, the manifold 220 may include multiple pathways that may be interconnected to improve fluid distribution or collection. In some exemplary embodiments, the manifold 220 may include or consist essentially of a porous material having interconnected fluid pathways. Examples of suitable porous materials that may be adapted to form interconnected fluid pathways (e.g., channels) may include cellular foams, including open-cell foams such as reticulated foams, porous tissue masses, and other porous materials such as gauze or felt mats that generally include pores, edges, and / or walls. Liquids, gels, and other foams may also include or harden to include openings and fluid passages. In some embodiments, the manifold 220 may additionally or alternatively include protrusions that form the interconnected fluid pathways. For example, the manifold 220 may be molded to provide surface protrusions that define the interconnected fluid pathways.

[0074] In some embodiments, the manifold 220 may include or consist essentially of a reticulated foam having a pore size and free volume that may vary depending on the needs of the indicated treatment. For example, a reticulated foam having at least 90% free volume may be suitable for many treatment applications, and a foam having an average pore size in the range of 400-600 micrometers (40-50 pores per inch) may be particularly suitable for some types of treatment. The tensile strength of the manifold 220 may also vary depending on the needs of the indicated treatment. The 25% compressive load deflection of the manifold 220 may be at least 0.35 pounds per square inch, and the 65% compressive load deflection may be at least 0.43 pounds per square inch. In some embodiments, the tensile strength of the manifold 220 may be at least 10 pounds per square inch. The manifold 220 may have a tear strength of at least 2.5 pounds per inch. In some embodiments, manifold 220 can be a foam composed of a polyol, such as a polyester or polyether, an isocyanate, such as toluene diisocyanate, and a polymerization modifier, such as an amine or tin compound. In some examples, manifold 220 can be a reticulated polyurethane foam such as found in GRANUFOAM™ dressings or VACVERAFLO™ dressings, both available from Kinetic Concepts, Inc. of San Antonio, Texas.

[0075] The thickness of manifold 220 may also be varied depending on the needs of the indicated treatment. For example, the thickness of manifold 220 may be reduced to reduce tension on the surrounding tissue at tissue site 202. The thickness of manifold 220 may also affect the conformability of manifold 220. In some embodiments, a thickness in the range of about 5 millimeters to 10 millimeters may be suitable.

[0076] In some exemplary embodiments, the manifold 220 may be hydrophilic. In examples in which the manifold 220 may be hydrophilic, the manifold 220 may also wick fluid away from the tissue site 202 while continuing to distribute negative pressure to the tissue site. The wicking properties of the manifold 220 may draw fluid away from the tissue site 202 by capillary flow or other wicking mechanisms. One example of a hydrophilic material that may be suitable is an open-cell foam of polyvinyl alcohol, such as VACWHITEFOAM™ dressing available from Kinetic Concepts, Inc. (San Antonio, Texas). Other hydrophilic foams may include those made from polyethers. Other foams that may exhibit hydrophilic characteristics include hydrophobic foams that have been treated or coated to impart hydrophilicity.

[0077] With continued reference to FIG. 2 and with reference to FIG. 3, the conduit interface 279 may be configured to fluidly couple the dressing 110 to the container 115 and the treatment unit 145. The conduit interface 279 may include a fluid connection 280 and a negative pressure port 282. The negative pressure port 282 may be disposed through the fluid connection 280, which may fluidly isolate the negative pressure port 282 from the absorbent material 224. The fluid connection 280 may extend into or be received by a negative pressure passageway 281 defined by an alignment of the opening 252 in the cover 125, the opening 261 in the absorbent material 224, and the opening 265 in the isolation layer 222. The fluid connection 280 may have a first surface 284 that may be configured to couple to the first surface 262 of the isolation layer 222. The fluid connection 280 may have a second surface 286 opposite the first surface 284. In other embodiments, the fluid connection 280 can extend through the cover 125 , the absorbent material 224 , and the isolation layer 222 and be coupled to the first surface 276 of the manifold 220 .

[0078] The negative pressure port 282 may extend from the second surface 286 to the first surface 284 through the fluid connection 280. The negative pressure port 282 may have an end 288 that may be configured to deliver negative pressure from the negative pressure source 105 to the manifold 220. The end 288 of the negative pressure port 282 may be proximate to the opening 265 of the isolation layer 222 and below or between the second surface 260 of the absorbent material 224 and the manifold 220 to deliver negative pressure through the opening 265 to the manifold 220. In some examples, the end 288 of the negative pressure port 282 may be fluidly sealed around the opening 265 of the isolation layer 222. In other examples, the negative pressure port 282 may bypass or extend through the absorbent material 224 such that the end 288 is disposed at or between the second surface 260 of the absorbent material 224 and the manifold 220. The negative pressure port 282 may be coupled to a conduit 290 which may be coupled to the reservoir 115 and the negative pressure source 105 of the treatment unit 145 .

[0079] 8A illustrates the treatment system 100 of FIG. 2 in an operational state in which the negative pressure source 105 of the treatment unit 145 delivers negative pressure to the tissue site 202. During operation, the negative pressure source 105 can draw fluid or exudate 802 from the tissue site 202, which can flow through the optional filler material 214, the optional base layer 218, and the manifold 220 to reach the negative pressure passageway 281. The exudate 802 can then flow through the negative pressure passageway 281 to the negative pressure port 282 and through the conduit 290 to the container 115. The container 115 may have a filter or other mechanism to retain the exudate 802 within the container 115 and prevent the exudate 802 from being aspirated into the treatment unit 145.

[0080] The plurality of valve flaps 270 of the first layer 266 of the isolation layer 222 can be closed when the negative pressure source 105 is activated. The plurality of valve flaps 270 can fluidly seal the plurality of holes 272 in the second layer 268 of the isolation layer 222. While the negative pressure source 105 is activated, the negative pressure passageway 281 can be in direct fluid communication with the manifold 220 and fluidly isolated from the absorbent material 224 such that exudate 802 cannot reach the absorbent material 224.

[0081] 8B illustrates the treatment system 100 of FIGS. 2 and 8A after the negative pressure source 105 has stopped delivering negative pressure to the tissue site 202. When the negative pressure source 105 has stopped delivering negative pressure to the tissue site 202, the valve flaps 270 of the first layer 266 of the isolation layer 222 can open. When open, the valve flaps 270 can expose the holes 272 of the second layer 268 of the isolation layer 222. Exudate 802 may flow from the tissue site 202 and the manifold 220 through the holes 272 and the valve flaps 270 of the isolation layer 222 and may be absorbed by the absorbent material 224. When the negative pressure source 105 is activated, the valve flaps 270 close and the exudate 802 can no longer reach the absorbent material 224. The exudate 802 then flows through the negative pressure passageway 281 to the reservoir 115 of the treatment system 100.

[0082] 9A-9D show another embodiment of an isolation layer 902 that can be used with the treatment system 100. The isolation layer 902 may include a first layer 904 and a second layer 906. There may be an opening 908 extending through both the first layer 904 and the second layer 906. The first layer 904 may include a plurality of holes 910 and the second layer may include a plurality of holes 912. The first layer 904 may be corrugated or textured in a quiescent state, as shown in FIGS. 9B and 9D. When in a quiescent state, the plurality of holes 910 of the first layer 904 and the plurality of holes 912 of the second layer 906 may allow for fluid flow through the isolation layer 902.

[0083] 9A and 9C, when negative pressure is applied to the dressing 110, the first layer 904 may flatten such that a second surface 914 of the first layer 904 is pressed against a first surface 916 of the second layer 906. When the first layer 904 is flat, the plurality of holes 910 of the first layer 904 may not be aligned with the plurality of holes of the second layer 910 such that the plurality of holes 912 of the second layer 906 are fluidly sealed by the first layer 904 and the plurality of holes 912 of the first layer 906 are fluidly sealed by the second layer 904. Thus, when the negative pressure source 105 is activated, the absorbent material 224 may be fluidly isolated from the manifold 220 and the tissue site 202. When the negative pressure source 105 is stopped, the first layer 904 can return to its resting state and fluid can flow through the multiple holes 910 in the first layer 904 and the multiple holes 912 in the second layer 906 to reach the absorbent material 224.

[0084] As mentioned above, some embodiments of the dressing 110 may include at least one spacer or protrusion to provide a pathway or space between the isolation layer 902 and the absorbent material 224. The pathway or space may allow the first layer 904 of the isolation layer 902 to move between its resting state and its flattened state when the negative pressure source 105 applies negative pressure to the dressing 110.

[0085] 10A-10B illustrate another embodiment of an isolation layer 1002 that can be used with the treatment system 100. The isolation layer 1002 can include an opening 1004, a valve flap 1006, and a number of holes 1008 surrounding the valve flap 1006. The opening 1004 can be coupled to the negative pressure passageway 281 as described above, and the valve flap 1006 can be configured to open and expose the opening 1004 when the negative pressure source 105 is activated. When the negative pressure source 105 is deactivated, the valve flap 1006 can close to stop fluid communication between the dressing 110 and the negative pressure passageway.

[0086] The plurality of holes 1008 may allow fluid communication between the absorbent material 224 and the manifold 220. However, when the negative pressure source 105 is activated, the exudate 802 may preferentially flow from the tissue site 202 through the manifold 220, the opening 1004, and the negative pressure passageway 281 to the container 115. A portion of the exudate 802 may flow through the plurality of holes 1008 and be absorbed by the absorbent material 224, but a majority of the exudate 802 is drawn into the container 115 by the negative pressure source 105. When the negative pressure source 105 is deactivated, the valve flap 1006 may close the opening 1004 and the exudate 802 may flow through the plurality of holes 1008 in the isolation layer 1002 and be absorbed by the absorbent material 224.

[0087] In some embodiments, the plurality of holes 1008 may each have a corresponding valve flap for restricting fluid flow through the isolation layer 1002 when the negative pressure source 105 is activated. In any of the above-described embodiments, the valve flap 1006 may be any type of check valve that allows fluid flow in a first direction from the tissue site toward the cover 125 of the dressing 110 and restricts fluid flow in a second direction from the absorbent material 224 toward the tissue site 202.

[0088] Also described herein is a method of treating a tissue site. The method may include applying a dressing 110 to a tissue site 202, fluidly coupling a negative pressure source 105 to a treatment space between the isolation layer 222 and the tissue site 202, such as the sealed space 256 shown in FIG. 2, such that the absorbent material 224 is bypassed, and activating the negative pressure source 105 to apply negative pressure to the treatment space. The isolation layer 222 may have one or more valves, such as a plurality of valve flaps 270, that may be moved from an open state without negative pressure to a closed state by the act of applying negative pressure.

[0089] The method may further include deactivating the negative pressure source 105 and collecting fluid from the tissue site 202 with the absorbent material 224. The fluid may be configured to flow through the isolation layer 222 to the absorbent material 224 when the negative pressure source 105 is deactivated and the one or more valves are returned to an open state.

[0090] The systems, devices, and methods described herein can provide significant advantages. For example, the treatment system 100 can prevent fluid from leaking from the dressing 110 after the negative pressure source 105 is turned off. The isolation layer 222 can allow the absorbent material 224 to capture any fluid that flows from the tissue site 202 after the negative pressure source 105 is turned off. The treatment system 100 can also prevent blockages as the absorbent material 224 is removed from the negative pressure path. This can allow the treatment system 100 to remain in place at the tissue site for a longer period of time, which can reduce costs and increase patient comfort.

[0091] While shown in several exemplary embodiments, those skilled in the art will appreciate that the systems, devices, and methods described herein are capable of various changes and modifications within the scope of the appended claims. Additionally, the description of various alternatives using terms such as "or" does not require mutual exclusivity unless clearly required by the context, and the indefinite article "a" or "an" does not limit the subject matter to a single case unless clearly required by the context. Components may also be combined or excluded in various configurations for purposes of sale, manufacture, assembly, or use. For example, in some configurations, the dressing 110, the container 115, or both may be excluded or separated from other components for manufacture or sale. In other exemplary configurations, the controller 130 may also be manufactured, configured, assembled, or sold independently of other components.

[0092] The appended claims recite the novelty and inventive step of the above-mentioned subject matter, but the claims may also encompass additional subject matter not specifically described in detail. For example, certain features, elements, or aspects may be omitted from the claims if they are not necessary to distinguish the novel and inventive features from those already known to those skilled 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 as defined by the appended claims.

Claims

1. A dressing for treating a tissue site using negative pressure, the dressing comprising: a cover including a first surface and a second surface opposite the first surface; an absorbent material including a first surface and a second surface opposite the first surface, the first surface of the absorbent material being adjacent to the second surface of the cover; an isolation layer configured to restrict fluid flow from the tissue site to the absorbent material when negative pressure is applied to the dressing, the isolation layer including a first surface and a second surface opposite the first surface, the first surface of the isolation layer being adjacent to the second surface of the absorbent material; a manifold having a first surface and a second surface opposite the first surface, the first surface of the manifold being adjacent to the second surface of the isolation layer; A dressing comprising:

2. The dressing according to claim 1, wherein the isolation layer is disposed between the absorbent material and the manifold.

3. The dressing according to claim 1, wherein the absorbent material is encapsulated between the cover and the isolation layer.

4. The dressing according to claim 1, wherein the manifold is configured to be disposed between the isolation layer and the tissue site.

5. The dressing according to claim 1, wherein the isolation layer comprises one or more valves configured to close when negative pressure is applied and open when the negative pressure is removed.

6. The dressing according to claim 5, wherein the one or more valves are check valves configured to allow fluid flow in a first direction from the second surface of the isolation layer toward the first surface of the isolation layer and prevent fluid flow in a second direction from the first surface of the isolation layer toward the second surface of the isolation layer.

7. The dressing according to claim 5, wherein the one or more valves prevent fluid flow in all directions when negative pressure is applied.

8. The dressing according to claim 5, wherein each of the one or more valves comprises a valve flap configured to close a hole through the isolation layer when negative pressure is applied and move away from the hole to provide a passage through the isolation layer when the negative pressure is removed.

9. The isolation layer comprises: a first layer including a plurality of valve flaps; A second layer having a plurality of holes aligned with the plurality of valve flaps of the first layer and configured to be fluidly sealed by the plurality of valve flaps of the first layer when the negative pressure is applied to the dressing. The dressing according to claim 1, comprising:

10. The isolation layer is A first layer including a corrugated material having a first plurality of holes; A second layer having a second plurality of holes configured to be fluidly sealed by the first layer when the negative pressure is applied to the dressing. The dressing according to claim 1, comprising:

11. The first plurality of holes and the second plurality of holes are configured to provide fluid communication between the manifold and the absorbent material when the dressing is in a stationary state and there is no negative pressure, and the first plurality of holes are configured not to be aligned with the second plurality of holes when the negative pressure is applied to the dressing to prevent fluid communication between the manifold and the absorbent material. The dressing according to claim 10.

12. Each of the cover, the absorbent material, and the isolation layer is aligned with each other and further includes a negative pressure passage configured to enable fluid communication between the manifold and a negative pressure source. The dressing according to claim 1.

13. The negative pressure passage is in direct fluid communication with the manifold and is fluidly isolated from the absorbent material. The dressing according to claim 12.

14. The negative pressure passage is configured to receive a fluid connection, and the fluid connection includes a negative pressure port positioned between the second surface of the absorbent material and the manifold. The dressing according to claim 12.

15. The fluid connection fluidly isolates the negative pressure port from the absorbent material. The dressing according to claim 14.

16. The fluid connection and the negative pressure port extend through the isolation layer to the first surface of the manifold. The dressing according to claim 14.

17. A dressing for treating a tissue site using negative pressure, the dressing comprising: A cover including a first surface and a second surface opposite the first surface; An absorbent material including a first surface and a second surface opposite the first surface, wherein the first surface of the absorbent material is adjacent to the second surface of the cover, the absorbent material, A separator layer, A first surface adjacent to the second surface of the absorbent material, A second surface opposite the first surface, A valve flap in fluid communication with a negative pressure source and configured to open when negative pressure is applied to the dressing and close when the negative pressure is stopped, A separator layer comprising a plurality of holes surrounding the valve flap, A manifold comprising a first surface and a second surface opposite the first surface, wherein the first surface of the manifold is adjacent to the second surface of the separator layer, the manifold, A dressing comprising.

18. A dressing for treating a tissue site using negative pressure, the dressing comprising An absorbent material, A manifold configured to distribute negative pressure to the tissue site, A separator layer disposed between the absorbent material and the manifold and configured to fluidly isolate the absorbent material from the manifold when negative pressure is applied to the manifold, A dressing comprising.

19. The dressing according to claim 18, wherein the manifold is configured to be disposed between the separator layer and the tissue site.

20. The dressing according to claim 18, wherein the separator layer comprises one or more valves configured to close when negative pressure is applied to the manifold and open when the negative pressure is removed.

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