Patent Description:
Improvements to therapy systems, components, and processes may benefit healthcare providers and patients. <CIT> discloses a reduced pressure connector including a first channel to couple a reduced pressure source to a wound and a second channel to couple an air vent to the wound. <CIT> and <CIT> disclose wound dressings which may include dialkyl carbomoyl chloride. <CIT> discloses a reduced pressure treatment dressing having a plurality of elongate members. <CIT> discloses an absorbent, negative pressure, wound treatment system. Further relevant prior art can be found in <CIT>.

According to claim <NUM>, there is provided an apparatus for treating a tissue site, comprising: a dressing; and a bridge adapted to be fluidly coupled to the dressing, the bridge comprising: a first manifold layer, a second manifold layer, a binding layer comprising a binding material positioned between the first manifold layer and the second manifold layer, wherein the binding material has bacterial-binding and protein-binding properties, and a sealing material having a first end and a second end, wherein the first end comprises an first aperture adapted to be fluidly coupled to a negative-pressure source, and the second end comprises an second aperture adapted to be fluidly coupled to the dressing; wherein the first manifold layer, the second manifold layer, and the binding layer are enclosed within the sealing material and are fluidly coupled between the first and second apertures.

A selection of optional features is set out in the dependent claims.

<FIG> is a simplified functional block diagram of an example embodiment of a therapy system <NUM> that can provide negative-pressure therapy to a tissue site in accordance with this specification.

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, partial-thickness burns, 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.

The therapy system <NUM> may include a source or supply of negative pressure, such as a negative-pressure source <NUM>, a dressing <NUM>, a fluid container, such as a container <NUM>, and a regulator or controller, such as a controller <NUM>, for example. As illustrated in <FIG>, for example, the therapy system <NUM> may include a pressure sensor <NUM>, an electric sensor <NUM>, or both, coupled to the controller <NUM>. As illustrated in the example of <FIG>, the dressing <NUM> may comprise or consist essentially of a tissue interface <NUM>, a cover <NUM>, or both in some embodiments. Also illustrated in the example of <FIG>, the therapy system <NUM> may include a bridge <NUM>, which may be positioned in fluid communication between the negative-pressure source <NUM> and the dressing <NUM>.

Some components of the therapy system <NUM> 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 <NUM> may be combined with the controller <NUM> and other components into a therapy unit.

For example, the negative-pressure source <NUM> may be directly coupled to the container <NUM>, and may be indirectly coupled to the dressing <NUM> through the container <NUM>. For example, the negative-pressure source <NUM> may be electrically coupled to the controller <NUM>, and may be fluidly coupled to one or more distribution components to provide a fluid path to a tissue site.

A distribution component is preferably detachable, and may be disposable, reusable, or recyclable. The dressing <NUM> and the container <NUM> are illustrative of distribution components. A "fluid conductor," in this context, broadly includes a tube, pipe, hose, conduit, or other structure with one or more lumina adapted to convey a fluid between two ends. Additionally, the bridge <NUM> is also illustrative of a distribution component, and may be more specifically considered as a fluid conductor. ™ Pad, commercially available from KCI, of San Antonio, Texas.

A negative-pressure supply, such as the negative-pressure source <NUM>, 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 micro-pump, 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 applied to a tissue site may vary according to therapeutic requirements, the pressure is generally a low vacuum, also commonly referred to as a rough vacuum, between -<NUM> Hg (-<NUM> Pa) and -<NUM> Hg (-<NUM> kPa). Common therapeutic ranges are between -<NUM> Hg (-<NUM> kPa) and -<NUM> Hg (-<NUM> kPa).

The container <NUM> is representative of a container, canister, pouch, or other storage component, which can be used to manage exudates and other fluid withdrawn from a tissue site. In many environments, a rigid container may be preferred or required for collecting, storing, and disposing of fluid. In other environments, fluid may be properly disposed of without rigid container storage, and a re-usable container could reduce waste and costs associated with negative-pressure therapy. In some embodiments, exudates and other fluid withdrawn from a tissue site may be managed or stored by the dressing <NUM> in addition to or instead of the container <NUM>. Thus, in some embodiments, a separate container <NUM> may be omitted from the therapy system <NUM> depending on the particular dressing <NUM> incorporated into the therapy system <NUM>.

Sensors, such as the pressure sensor <NUM> or the electric sensor <NUM>, 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 pressure sensor <NUM> and the electric sensor <NUM> may be configured to measure one or more operating parameters of the therapy system <NUM>. In some embodiments, the pressure sensor <NUM> 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 pressure sensor <NUM> may be a piezoresistive strain gauge. The electric sensor <NUM> may optionally measure operating parameters of the negative-pressure source <NUM>, such as the voltage or current, in some embodiments. Preferably, the signals from the pressure sensor <NUM> and the electric sensor <NUM> are suitable as an input signal to the controller <NUM>, but some signal conditioning may be appropriate in some embodiments.

The tissue interface <NUM> can be generally adapted to contact a tissue site. The tissue interface <NUM> may be partially or fully in contact with a tissue site. If a tissue site is a wound, for example, the tissue interface <NUM> may partially or completely fill the wound, or may be placed over the wound. The tissue interface <NUM> 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. Moreover, any or all of the surfaces of the tissue interface <NUM> may have projections or an uneven, course, or jagged profile that can induce strains and stresses on a tissue site, which can promote granulation at the tissue site.

In some embodiments, the tissue interface <NUM> may comprise or consist of a manifold. A "manifold" in this context generally includes any substance or structure providing a plurality of pathways adapted to collect or distribute fluid across a tissue site under pressure. For example, a manifold may be adapted to receive negative pressure from a source and distribute negative pressure through multiple apertures across a tissue site, 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 across a tissue site.

In some illustrative embodiments, the pathways of a manifold may be interconnected to improve distribution or collection of fluid across a tissue site. In some illustrative embodiments, a manifold may be a porous foam material having interconnected cells or pores. The average pore size of a foam may vary according to needs of a prescribed therapy. For example, in some embodiments, the tissue interface <NUM> may be a foam having pore sizes in a range of <NUM>-<NUM> microns. The tissue interface <NUM> 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 <NUM> may draw fluid away from a tissue site by capillary flow or other wicking mechanisms. Additionally, in some embodiments, the tissue interface <NUM> may be constructed from bioresorbable materials.

In some embodiments, the cover <NUM> may provide a bacterial barrier and protection from physical trauma. The cover <NUM> 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 <NUM> may be, 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 <NUM> may have a high moisture-vapor transmission rate (MVTR) in some applications. For example, the MVTR may be at least <NUM>/m<NUM> per twenty-four hours, measured by upright cup technique, according to ASTM E96/E96M Upright Cup Method at <NUM> and <NUM>% relative humidity (RH). In some embodiments, the cover <NUM> may have a MVTR between <NUM>/m<NUM> per twenty-four hours and <NUM>,<NUM>/m<NUM> per twenty-four hours. In some example embodiments, the cover <NUM> 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 <NUM>-<NUM> microns. For permeable materials, the permeability generally should be low enough that a desired negative pressure may be maintained.

The cover <NUM> may include a sealing material, which may be formed from any material that allows for a fluid seal to be provided. For example, the cover <NUM> 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 rubber; 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, for example, Tegaderm® drape, commercially available from <NUM> Company, Minneapolis Minnesota; polyurethane (PU) drape, commercially available from Avery Dennison Corporation, Pasadena, California; polyether block polyamide copolymer (PEBAX), for example, from Arkema S. , Colombes, France; and Inspire <NUM> and Inpsire <NUM> polyurethane films, commercially available from Expopack Advanced Coatings, Wrexham, United Kingdom. In some embodiments, the cover <NUM> comprises INSPIRE <NUM> having an MVTR (upright cup technique) of <NUM>/m<NUM>/<NUM> hours and a thickness of about <NUM> microns.

An attachment device may be used to attach the cover <NUM> 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 <NUM> to epidermis around a tissue site. In some embodiments, for example, some or all of the cover <NUM> may be coated with an adhesive, such as an acrylic adhesive, which may have a coating weight between <NUM>-<NUM>/m<NUM> (gsm). 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.

The fluid mechanics of using a negative-pressure source to reduce pressure in another component or location, such as within a sealed therapeutic environment, can be mathematically complex. However, the basic principles of fluid mechanics applicable to negative-pressure therapy are generally well-known to those skilled in the art, and the process of reducing pressure may be described illustratively herein as "delivering," "distributing," or "generating" negative pressure, for example.

In general, exudates and other fluids flow toward lower pressure along a fluid path. Thus, the term "downstream" typically implies something 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" implies something 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.

The cover <NUM> may be placed over the tissue interface <NUM> and sealed to an attachment surface near the tissue site. Thus, the dressing <NUM> can provide a sealed therapeutic environment proximate to a tissue site, substantially isolated from the external environment, and the negative-pressure source <NUM> can reduce the pressure in the sealed therapeutic environment. Negative pressure applied across the tissue site through the tissue interface <NUM> in the sealed therapeutic environment can induce macrostrain and micro-strain in the tissue site, as well as remove exudates and other fluids from the tissue site, which can be collected in container <NUM>.

An important factor for efficient fluid management across the components of a system for providing negative-pressure therapy, such as therapy system <NUM>, is the proper management of high viscosity fluid. Higher viscosity fluids may be more likely to cause occlusions or become resistant to movement within some wound dressings or other system components. The impairment of fluid movement may cause some dressings or other system components to fill with wound fluid, which may result in creating a pressure differential or drop between the pressure level at a source of negative-pressure and the pressure level at a tissue site. Often, the more difficult types of fluids to manage are the higher viscosity wound fluids, such as fluids having a viscosity of around <NUM> mPa·s. Such higher viscosity wound fluids often have higher protein content, and following a period of heavy exudate, which may be around <NUM>-<NUM> days into treatment, the proteins may begin to impair the ability of a wound dressing or other components of negative-pressure therapy systems to effectively transport wound fluid and facilitate wound fluid movement out of the wound dressing or other system components. Furthermore, in such dressings or negative-pressure devices or systems that include components designed to at least partially evaporate fluid, the higher protein content may also begin to interfere with the evaporation of wound fluid from a dressing or other components of a therapy system. This reduction in evaporation of fluid may exacerbate pressure drops in one or more dressing or system components.

Negative-pressure dressings or systems which may be particularly susceptible to occlusions and resulting pressure drops may be those which include a long, slender, vertical component, such as a conduit or other fluid conductor, between a source of negative pressure and a base wound dressing, which may be positioned at a relatively lower vertical position on a patient and perhaps underneath a compression garment. For example, dressings and other aspects of negative-pressure systems used for the treatment of a venous leg ulcer (VLU) may be vulnerable to such pressure drops. VLUs often produce protein-rich fluid having a relatively high viscosity. Given that it is often preferable for target wear times of some dressings for VLUs and other types of tissue sites, as well as overlying compression garments, to be up to <NUM> days before changing, such occlusions and pressure drops prior to the conclusion of the <NUM>-day period may be particularly disruptive to patient lifestyle and healing, as the dressing components may need to be discarded. Costs may also be increased due to the possible discarding of both the dressing components as well as other components of the negative-pressure system.

Distribution components of the therapy system <NUM> can manage high-viscosity fluid, particularly protein-rich fluid of varying viscosities produced by VLUs. In some embodiments of the therapy system <NUM>, a dressing or conduit structure for mitigating the effects of high protein content in viscous wound exudate may be provided. Such a structure may include a material that can bind particular components associated with wound exudate, including among others, bacteria and one or more types of protein.

<FIG> is a schematic diagram illustrating additional details that may be associated with some example embodiments of the therapy system <NUM>. In the example embodiment of <FIG>, a dressing <NUM> and bridge <NUM> are shown. The bridge <NUM> is an example embodiment of the bridge <NUM> of <FIG>. The bridge <NUM> may fluidly couple the dressing <NUM> and the negative-pressure source <NUM> in any suitable manner. In some embodiments, the bridge <NUM> may have a first end <NUM> and a second end <NUM>. The length of the bridge <NUM> may be any length suitable for a particular application to a tissue site, such as a VLU. For example, in some embodiments, the length of the bridge <NUM> may be between about <NUM> millimeters and about <NUM> millimeters. In some embodiments, the bridge <NUM> may also include an attachment port <NUM> for fluidly connecting a source of negative pressure, such as negative-pressure source <NUM>, to the bridge <NUM>. For example, in some embodiments, the attachment port <NUM> may be configured to be coupled to a fluid conduit, such as a tube, which may terminate in an adapter for fluid connection to the negative-pressure source <NUM>.

<FIG> is an exploded view of the bridge <NUM> of <FIG>, showing additional details and features that may be associated with some illustrative embodiments. The bridge <NUM> may include a sealing member, which may be formed of one or more layers of sealing material, such as a first sealing layer <NUM> and a second sealing layer <NUM>. The first sealing layer <NUM> may have a first periphery bonded to a second periphery of the second sealing layer <NUM>. In some embodiments, the first periphery of the first sealing layer <NUM> may be welded or joined with an adhesive to the second periphery of the second sealing layer <NUM>. Between the first sealing layer <NUM> and the second sealing layer <NUM> may be an internal passageway. Within the internal passageway, the bridge <NUM> may include one or more layers of a manifold material. For example, the layers of manifold material may be encapsulated or sealingly enclosed between the first sealing layer <NUM> and the second sealing layer <NUM> and also between the first end <NUM> and the second end <NUM> of the bridge <NUM>. In some embodiments, the first sealing layer <NUM> may have a first periphery bonded to a second periphery of the second sealing layer <NUM> around the layers of manifold material in any suitable manner. Additionally or alternatively, the sealing member may be formed of a single layer of sealing material, which may be folded or wrapped around the other components of the bridge <NUM> and joined and sealed along two edges of the single layer of sealing material. The two edges of the single layer of sealing material may be joined through welding, the use of an adhesive, or other attachment means. Furthermore, the sealing member may also be in the form of a sleeve, which may be produced using an extrusion or other process.

The one or more layers of sealing material, such as the first sealing layer <NUM> and the second sealing layer <NUM>, may be comprised of similar materials described above for the cover <NUM>. For example, the layers of sealing material may each be an adhesive-coated film, such as an adhesive-coated polyurethane film. In some embodiments, the layers of sealing material may be an INSPIRE <NUM> or INSPIRE <NUM> drape. The structure of the bridge <NUM> may, in some embodiments, replace the need for including more traditional conduit structures and materials, such as plastic tube sets, in parts of the therapy system <NUM>. Further, other materials for the one or more layers of sealing material may be used, such as polyurethane film, films with and without adhesive, and other high-MVTR films. High-MVTR films may provide for evaporation of condensate. In some preferred embodiments, the bridge <NUM> may include one or more thin, flexible non-woven manifold material layers sealed between two layers of sealing material, such as the first sealing layer <NUM> and the second sealing layer <NUM>, which may be polyurethane layers or other occlusive layers which may be bonded or sealed together.

In some embodiments, the first sealing layer <NUM> may include an adhesive layer on an external surface. For example, the external surface of the first sealing layer <NUM> may further include a layer of a double-sided adhesive tape, which may have a release liner protecting the external adhesive surface prior to application to the skin of a patient. The adhesive layer may include any suitable adhesive material, including adhesive acrylates, however those adhesives that provide an adequate tack without causing harm to a patient's skin may be most appropriate.

In some embodiments, patterns or shallow ridges may be embossed into the first sealing layer <NUM> and/or the second sealing layer <NUM> to aid pressure transfer and further resist crushing. Further, odor-absorbing additives may be added to the bridge <NUM> to absorb bad-smelling gases and vapors that may be liberated from the wound or dressing.

As previously mentioned, the bridge <NUM> may include one or more layers of a manifold material encapsulated or sealingly enclosed within the one or more layers of sealing material. For example, the bridge <NUM> may include a first manifold layer <NUM>, a second manifold layer <NUM>, and a third manifold layer <NUM>. Each of the one or more layers of manifold material may extend along the length of the bridge <NUM> and may be disposed within the internal passageway that may be defined by the one or more layers of the sealing member. In some embodiments, the bridge <NUM> may include additional layers of manifold material, for example, a fourth manifold layer and a fifth manifold layer, depending on the particular application. In additional example embodiments, the bridge <NUM> may include only one or two layers of manifold material.

In some embodiments, the manifold material may include a wicking material. Furthermore, the one or more layers of manifold material may include a non-woven material, such as, for example, a polyester non-woven. In some embodiments, the one or more layers of manifold material may include Libeltex TDL4 co-polyester, commercially available from Libeltex BVBA, Meulebeke, Belgium. In some embodiments, other non-woven materials may be used for the manifold material, such as Freudenberg M1505, commercially available from Freudenberg Group, Weinheim, Germany; a compressed polyolefin, commercially available from Essentra PLC, Buckinghamshire, United Kingdom; or Libeltex TDL2, commercially available from Libeltex BVBA, Meulebeke, Belgium. In additional embodiments, the manifold material may be an open-celled polyurethane foam or laminations with fiber or foam structures.

A periphery or edge of the first manifold layer <NUM> may be coupled to a periphery or edge of the second manifold layer <NUM> in any suitable manner, such as, for example, by a weld. A periphery or edge of the second manifold layer <NUM> may also be coupled to a periphery or edge of the third manifold layer <NUM> in any suitable manner, such as, for example, by a weld. The second manifold layer <NUM> may be positioned between the first manifold layer <NUM> and the third manifold layer <NUM>. In some embodiments, the one or more manifold layers, such as the first manifold layer <NUM>, second manifold layer <NUM>, and third manifold layer <NUM>, may be positioned and sealed between the first sealing layer <NUM> and the second sealing layer <NUM> of the sealing member without any welds between the manifold layers.

In some embodiments, the one or more manifold layers, such as the first manifold layer <NUM>, the second manifold layer <NUM>, and the third manifold layer <NUM>, may each include an acquisition side and a distribution side. For example, the first manifold layer <NUM> may include an acquisition side 360a and a distribution side 362a, the second manifold layer <NUM> may include an acquisition side 360b and a distribution side 362b, and the third manifold layer <NUM> may include an acquisition side 360c and a distribution side 362c. The distribution sides 362a-c may be positioned on opposite sides or surfaces of the first manifold layer <NUM>, the second manifold layer <NUM>, and the third manifold layer <NUM> from the acquisition sides 360a-c. For example, the acquisition sides 360a-c of each of the first manifold layer <NUM>, the second manifold layer <NUM>, and the third manifold layer <NUM> may face in a direction of the first sealing layer <NUM>. Further, the distribution sides 362a-c of each of the first manifold layer <NUM>, the second manifold layer <NUM>, and the third manifold layer <NUM> may face in a direction of the second sealing layer <NUM>. However, each or all of the first manifold layer <NUM>, the second manifold layer <NUM>, and the third manifold layer <NUM> may be oppositely oriented, so that a variety of embodiments may be achieved, with different combinations of the acquisition sides 360a-c and distribution sides 362a-c of the first manifold layer <NUM>, the second manifold layer <NUM>, and the third manifold layer <NUM> being oriented towards either the first sealing layer <NUM> or the second sealing layer <NUM>.

The bridge <NUM> further includes a binding material having bacterial-binding as well as protein-binding properties. The bridge <NUM> includes a binding layer <NUM>, which is in the form of a layer of binding material, positioned between the first manifold layer <NUM> and the second manifold layer <NUM> of the bridge <NUM>. Alternatively, the binding layer <NUM> may also be positioned between the second manifold layer <NUM> and the third manifold layer <NUM>. Additional embodiments of the bridge <NUM> may include multiple layers of the binding material, for example, with a first layer of binding material, such as binding layer <NUM>, positioned between the first manifold layer <NUM> and the second manifold layer <NUM> and a second layer of binding material positioned between the second manifold layer <NUM> and the third manifold layer <NUM>. Additional or alternative embodiments may include different arrangements of layers of the binding material and manifold layers based on the particular need or application.

In some embodiments, the binding layer <NUM> may be in the form of a mesh. The binding layer <NUM> may allow for substantially even distribution of negative pressure within the bridge <NUM>, while reducing or preventing the spread of microorganism growth, particularly bacteria, which if left untreated may spread infection in a tissue site. For example, bacteria and other microorganisms may include gram positive bacteria, such as Staphylococcus aureus, MRSA, or Streptococci; gram negative bacteria such as E. coli or Pseudomonas aeruginosa; fungi, such as Candida albicans; as well as others.

The binding layer <NUM> may be in the form of a sheet or layer, which may include fibers coated with a material having a high affinity for binding bacteria and also proteins. In some embodiments, the binding layer <NUM> may be in the form of a low-profile layer, or <NUM>-D lattice work coated with binding material, so as to add minimal volume to the bridge <NUM>. For example, the coating material may include dialkyl carbamoyl chloride (DACC) hydrophobic coating, such as used in Cutimed® Sorbact®, commercially available from BSN Medical. The following is a representative chemical structure of DACC. <CHM>
wherein R is lower alkyl, such as methyl.

As is evident from the above chemical structure, DACC includes both nonpolar groups (the methyl (or alkyl) entities), and polar groups (oxygen, nitrogen, and chlorine). Accordingly, the DACC may demonstrate a dipolar character, which is also a characteristic of many proteins. The polar groups of DACC may increase the hydrophilicity of the molecule, which in some instances may be counteracted by increasing the chain length of the alkyl groups. Additionally, molecules with similar polar groups as to those of the DACC molecule could be selected to replicate the dipolar nature.

The binding material of the binding layer <NUM> may attract the bacteria and proteins through hydrophobic interaction, which is the principle that when two hydrophobic particles come together, they bind with the force of the surrounding water molecules. For example, protein molecules expressing surface hydrophobicity may be attracted to and held by the binding material, thus helping to separate the protein molecules from surrounding water molecules present in the wound exudates. As a result, the protein molecules may remain bound to the binding material and be kept away from blocking the fluid manifolding pathways in the bridge <NUM> that manifold pressure, move fluids, and ultimately facilitate the evaporation of much of the water present in the wound exudates before it travels the container <NUM>.

Since most bacterial pathogens are hydrophobic, in the semi-aqueous environment of a tissue site, which includes a wound or wound exudates leaving a wound, the binding material and the bacterial pathogens may have an affinity for binding together if the binding material is hydrophobic. If the bacteria are bound to the binding material, the bacteria may be rendered unable to reproduce or release harmful toxins to the tissue site. Furthermore, by including the binding material in a binding layer <NUM> within the bridge <NUM>, the bacteria may be kept remote from a tissue site; however, the binding material may still be in close enough fluid communication with fluid leaving the tissue site to be effective.

Regardless of the exact positioning of the binding layer <NUM>, the binding layer <NUM> may offer the greatest benefit if it is between layers of the manifold material, such as for example, between the first manifold layer <NUM> and the second manifold layer <NUM> of the bridge <NUM>. In such a configuration, bacteria-rich and/or protein-rich fluid from a tissue site may move along the surface area on both sides of the binding layer <NUM>. Further, the movement of fluid along the sides of the binding layer <NUM> may be assisted by the wicking or manifolding functionality of the layers of the manifold material. As shown in the illustrative embodiment depicted in <FIG>, the binding layer <NUM> may comprise a DACC-coated material and may be disposed between two of the three layers of the manifold material, all of which may be encapsulated within the sealing member.

Still referring primarily to <FIG>, the bridge <NUM> may include one or more apertures for being fluidly connected to other components of the therapy system <NUM>. For example, the second sealing layer <NUM> may include a first aperture <NUM> at the first end <NUM> of the bridge <NUM>. Additionally, the first sealing layer <NUM> may include a second aperture <NUM> at the second end <NUM> of the bridge <NUM>. The first end <NUM> and the first aperture <NUM> may be in fluid communication with the second end <NUM> and the second aperture <NUM> through the length of the bridge <NUM>. In some embodiments, a seal <NUM> may be positioned about the second aperture <NUM> and between the second end <NUM> of the bridge <NUM> and the dressing <NUM> for bonding the second end <NUM> of the bridge <NUM> to the dressing <NUM> and for maintaining fluid communication between the bridge <NUM> and the dressing <NUM> through the second aperture <NUM>. In some embodiments, a conduit interface <NUM> may be included and positioned proximate to the bridge <NUM> and in fluid communication with the attachment port <NUM> and the first aperture <NUM> of the first end <NUM> of the bridge <NUM>. The conduit interface <NUM> may communicate negative pressure from the negative-pressure source <NUM> to the bridge <NUM>. The conduit interface <NUM> may comprise a medical-grade, soft polymer or other pliable material. As non-limiting examples, the conduit interface <NUM> may be formed from polyurethane, polyethylene, polyvinyl chloride (PVC), fluorosilicone, or ethylene-propylene. In some illustrative, non-limiting embodiments, the conduit interface <NUM> may be molded from PVC which is free from di(<NUM>-ethylhexyl)phthalate (DEHP). The conduit interface <NUM> may be formed in any suitable manner, such as by molding, casting, machining, or extruding. Further, the conduit interface <NUM> may be formed as an integral unit or as individual components and may be coupled to the bridge <NUM> by, for example, adhesive or welding.

In some embodiments, the conduit interface <NUM> may include an odor filter or material adapted to substantially preclude the passage of odors from the bridge <NUM>. In some embodiments, the odor filter may be comprised of a carbon material in the form of a layer or particulate. For example, the odor filter may comprise a woven carbon cloth filter such as those manufactured by Chemviron Carbon, Ltd. of Lancashire, United Kingdom. Further, in some instances, the conduit interface <NUM> may carry a hydrophobic filter adapted to substantially preclude the passage of liquids out of the bridge <NUM>. The hydrophobic filter may be comprised of a material that is substantially liquid impermeable and vapor permeable. For example, the hydrophobic filter may comprise a GORE™ Medical Membrane MMT-<NUM>, commercially available from W. Gore & Associates, Inc. of Newark, Delaware. The hydrophobic filter may be in the form of a membrane or layer.

The odor filter and/or hydrophobic filter may be disposed in the conduit interface <NUM> or other suitable location such that fluid communication between the negative-pressure source <NUM> and the dressing <NUM> is provided through the odor filter and/or hydrophobic filter. In some embodiments, the odor filter and/or the hydrophobic filter may be secured within the conduit interface <NUM> in any suitable manner, such as by adhesive or welding.

<FIG> illustrates an additional embodiment of a bridge <NUM>, which may be substantially similar to the bridge <NUM> shown in <FIG>, and may be an example embodiment of the bridge <NUM> of <FIG>. In addition to the components described with respect to the bridge <NUM> of <FIG>, the bridge <NUM> may also include absorbent layer <NUM>. Absorbent layer <NUM> may include an absorbent component, and in some embodiments, may include a super-absorbent material. The absorbent layer <NUM> may be positioned next to or sandwiched between the one or more layers of manifold material, for example between the first manifold layer <NUM> and the second manifold layer <NUM>. In some embodiments, the absorbent layer <NUM> may also be positioned adjacent to the binding layer <NUM>. Additionally or alternatively, the absorbent layer <NUM> may also be positioned between or adjacent other layers of the bridge <NUM>. The absorbent layer <NUM>, which may include a super-absorbent material, may enable or enhance the ability of the bridge <NUM> to store fluid, such as wound exudates from a tissue site.

<FIG> illustrates a cross-section view of an example embodiment of one layer of manifold material, such as the first manifold layer <NUM>. In some embodiments, the acquisition side 360a may be comprised of vertical fibers <NUM>, and the distribution side 362a may be comprised of longitudinal fibers <NUM>. The longitudinal fibers <NUM> may be oriented substantially in a longitudinal direction along the length of the first manifold layer <NUM>, which may largely correspond to the length of the bridge <NUM>. The vertical fibers <NUM> may be oriented substantially vertical or normal relative to the longitudinal fibers <NUM> and the length of the first manifold layer <NUM> and the bridge <NUM>. The distribution side 362a may be coupled to the acquisition side 360a. Fluid communication voids <NUM> may be located or defined between and among the longitudinal fibers <NUM> of the distribution side 362a and the vertical fibers <NUM> of the acquisition side 360a. The fluid communication voids <NUM> may provide fluid communication through the first manifold layer <NUM> of the manifold material even when exposed to a force, such as compression force depicted in <FIG> as arrows <NUM>, for example. When exposed to such a force, the longitudinal fibers <NUM> and the vertical fibers <NUM> may engage one another to substantially preclude blockage, closure, or other interference with the fluid communication voids <NUM> in providing fluid communication through the first manifold layer <NUM> of the manifold material, as well as the overall bridge <NUM>.

During operation of the therapy system <NUM>, the negative-pressure source <NUM> may be activated to provide negative pressure to the dressing <NUM>. For example, in some of the embodiments employing the bridge <NUM>, negative pressure may be provided to the first end <NUM> of the bridge <NUM>. The negative pressure may be transmitted through the layers of manifold material in the internal passageway provided by the sealing member. The negative pressure may be further transmitted through the second end <NUM> of the bridge <NUM> and into the dressing <NUM> and to a tissue site.

Negative pressure can be transmitted to the dressing <NUM> and tissue site to draw, wick, or pull fluid from the tissue site into the dressing <NUM>, and further into the bridge <NUM>. As fluid enters the bridge <NUM> through the second end <NUM>, the fluid may be moved through the second aperture <NUM> and contact the fluid acquisition side 360a of the first manifold layer <NUM>. The fluid acquisition side 360a of the first manifold layer <NUM> may receive the fluid so that the fluid may be transported through the first manifold layer <NUM>. Subsequently, the fluid distribution side 362a of the first manifold layer <NUM> may transmit some of the fluid along the length of the first manifold layer <NUM> and bridge <NUM> within the internal passageway to the first end <NUM>. The fluid distribution side 362a of the first manifold layer <NUM> may also transmit some portion of the fluid to the fluid acquisition side 360b of the second manifold layer <NUM>.

As fluid is transmitted from the fluid distribution side 362a of the first manifold layer <NUM>, the fluid may contact at least a peripheral portion of the fluid acquisition side 360b of the second manifold layer <NUM>. The fluid acquisition side 360b of the second manifold layer <NUM> may receive the fluid so that the fluid may be transported through the second manifold layer <NUM>. Subsequently, the fluid distribution side 362b of the second manifold layer <NUM> may transmit the fluid directly to the first end <NUM> of the bridge <NUM>. However, in some embodiments, the fluid distribution side 362b of the second manifold layer <NUM> may also transmit fluid to a fluid acquisition side 360c of the third manifold layer <NUM>. The fluid may thus also be transported through the third manifold layer <NUM> along a third distribution side 362c of the third manifold layer <NUM> towards the first end <NUM> of the bridge <NUM>.

As fluid is moved along the length of the bridge <NUM> by the one or more manifold layers, as well as between the manifold layers, such as the first manifold layer <NUM>, the second manifold layer <NUM>, and the third manifold layer <NUM>, at least some amount of the fluid may pass along or through the binding layer <NUM>. As the fluid passes along or through the binding layer <NUM>, the binding material of the binding layer <NUM> may bind proteins as well as bacteria, particularly when the fluid possesses a higher viscosity due to a high concentration of proteins or bacteria. As proteins and bacteria are bound by the binding layer <NUM>, the remaining components of the fluid may continue to be transported along or through the manifold layers. Rather than the highly-viscous protein components of the fluid becoming saturated in the one or more manifold layers and thus impairing or preventing the transmission of the fluid, as well as negative pressure, through and along the manifold layers, the proteins may remain bound to or within the binding layer <NUM>. The remaining fluid components may continue to be transported through the bridge <NUM>. With the improved fluid flow provided by the inclusion of the binding layer <NUM>, fluid may be better transmitted via the one or more manifold layers along the length of the bridge <NUM>. Additionally, more effective evaporation of the fluid, in the form of vapor, through the portions of the sealing member, such as the second sealing layer <NUM>, may be maintained throughout the duration of the therapy system <NUM> being applied to a patient.

<FIG> illustrates features of another illustrative embodiment of a dressing, dressing <NUM>. Dressing <NUM> may include a tissue interface <NUM> and a cover <NUM>, as well as additional manifold layers and a binding material for binding bacteria and/or proteins. For example, in some embodiments, the dressing <NUM> may include a tissue interface <NUM>, a first manifold layer <NUM>, a second manifold layer <NUM>, a cover <NUM>, and an adhesive <NUM>. The dressing <NUM> may further include a binding layer <NUM>. Components of the dressing <NUM> may be added or removed to suit a particular application.

In some embodiments, the tissue interface <NUM> may have a periphery <NUM> surrounding a central portion <NUM>, and a plurality of apertures <NUM> disposed throughout the periphery <NUM> and the central portion <NUM>. The tissue interface <NUM> may also have a border <NUM> substantially surrounding the central portion <NUM> and positioned between the central portion <NUM> and the periphery <NUM>. The border <NUM> may be free of the apertures <NUM>. The tissue interface <NUM> may be adapted to cover the tissue site as well as the tissue surrounding the tissue site, such that the central portion <NUM> of the tissue interface <NUM> is positioned adjacent to or proximate to the tissue site, and the periphery <NUM> is positioned adjacent to or proximate to tissue surrounding the tissue site. Further, the apertures <NUM> in the tissue interface <NUM> may be in fluid communication with the tissue site and tissue surrounding the tissue site. In some embodiments, the dressing <NUM> may further include an additional structure for placement against or within the tissue site, such as a wound filler.

The apertures <NUM> in the tissue interface <NUM> may have any shape, such as for example, circles, squares, stars, ovals, polygons, slits, complex curves, rectilinear shapes, triangles, or other shapes. The apertures <NUM> may be formed by cutting, by application of local RF energy, or other suitable techniques for forming an opening. As shown in <FIG>, each of the plurality of apertures <NUM> may be substantially circular in shape. Each of the plurality of apertures <NUM> may have an area, which may refer to an open space or open area defining each of the plurality of apertures <NUM>. The area of each of the plurality of apertures <NUM> may be substantially the same, or the areas of individual apertures of the plurality of apertures <NUM> may vary depending, for example, on the position of the individual aperture in the tissue interface <NUM>. For example, the area of the apertures <NUM> in the periphery <NUM> may be larger than the area of the apertures <NUM> in the central portion <NUM> of the tissue interface <NUM>. The plurality of apertures <NUM> may have a uniform pattern or may be randomly distributed on the tissue interface <NUM>. The size and configuration of the plurality of apertures <NUM> may be designed to control the adherence of the cover <NUM> to an epidermis surrounding a tissue site.

In some embodiments, the plurality of apertures <NUM> positioned in the periphery <NUM> of the tissue interface <NUM> may be apertures 544a. Additionally, the plurality of apertures <NUM> positioned at corners of the periphery <NUM> of the tissue interface <NUM> may be apertures 544b. Furthermore, the plurality of apertures <NUM> positioned in the central portion <NUM> of the tissue interface <NUM> may be apertures 544c. Each of the apertures 544a-544c may vary in size. However, in some embodiments, the apertures 544a may have a diameter between about <NUM> millimeters to about <NUM> millimeters. The apertures 544b may have a diameter between about <NUM> millimeters to about <NUM> millimeters. The apertures 544c may have a diameter between about <NUM> millimeters to about <NUM> millimeters. Furthermore, the spacing between each of the apertures 544a-c may also vary depending on the specific embodiment. For example, in some embodiments, the diameter of each of the apertures 544a may be separated from one another by a distance of between about <NUM> millimeters to about <NUM> millimeters. Further, the diameter of at least one of the apertures 544a may be separated from the diameter of at least one of the apertures 544b by approximately a distance of about <NUM> millimeters to about <NUM> millimeters. The diameter of each of the apertures 544b may also be separated from one another by a similar distance. Additionally, a center of one of the apertures 544c may be separated from a center of another of the apertures 544c in a first direction by a distance of between about <NUM> millimeters to about <NUM> millimeters. In a second direction transverse to the first direction, the center of one of the apertures 544c may be separated from the center of another of the apertures 544c by a distance of between about <NUM> millimeters to about <NUM> millimeters. As shown in <FIG>, the distances may be increased for the apertures 544c in the central portion <NUM> being positioned proximate to or at the border <NUM> as compared to the apertures 544c positioned away from the border <NUM>.

As shown in <FIG>, the central portion <NUM> of the tissue interface <NUM> may be substantially square with each side of the central portion <NUM> having a length of between about <NUM> millimeters to about <NUM> millimeters. In some embodiments, the length may be between about <NUM> millimeters to about <NUM> millimeters. The dimensions of each section of the tissue interface <NUM>, such as the periphery <NUM>, the center portion <NUM>, and the border <NUM> may vary based on the particular application of the dressing <NUM>.

The tissue interface <NUM> may be a soft, pliable material suitable for providing a fluid seal with a tissue site. For example, the tissue interface <NUM> may comprise a silicone gel, a soft silicone, hydrocolloid, hydrogel, polyurethane gel, polyolefin gel, hydrogenated styrenic copolymer gel, a foamed gel, a soft closed-cell foam such as polyurethanes and polyolefins coated with an adhesive, polyurethane, polyolefin, or hydrogenated styrenic copolymers. In some embodiments, the tissue interface <NUM> may be perforated silicone layer or a non-adherent polyurethane or polyethylene film. The tissue interface <NUM> may also be an ethylene vinyl acetate (EVA) mesh. The tissue interface <NUM> may have a thickness between about <NUM> micrometers and about <NUM>,<NUM> micrometers. Further, in some embodiments, the tissue interface <NUM> may be comprised of hydrophobic or hydrophilic materials.

In some embodiments (not shown), the tissue interface <NUM> may be a hydrophobic-coated material. For example, the tissue interface <NUM> may be formed by coating a spaced material, such as, for example, woven, nonwoven, molded, or extruded mesh with a hydrophobic material. The hydrophobic material for the coating may be a soft silicone, for example.

The adhesive <NUM> may be in fluid communication with the plurality of apertures <NUM> in at least the periphery <NUM> of the tissue interface <NUM>. In this manner, the adhesive <NUM> may be in fluid communication with tissue surrounding a tissue site through the plurality of apertures <NUM> in the tissue interface <NUM>. The adhesive <NUM> may extend or be passed through the plurality of apertures <NUM> to contact epidermis for securing the cover <NUM> to, for example, tissue surrounding a tissue site. The plurality of apertures <NUM> may provide sufficient contact of the adhesive <NUM> to the epidermis to secure the cover <NUM> about a tissue site. The plurality of the apertures <NUM> and the adhesive <NUM> may also be configured to permit release and repositioning of the cover <NUM> about a tissue site.

In some embodiments, an additional or alternative attachment device may be used to secure the cover <NUM> about the tissue site. For example, double-sided tape, paste, hydrocolloid, hydrogel, silicone gel, or organogel may be used. Furthermore, thicker adhesives, or combinations of adhesives, may be applied in some embodiments to improve seals and to reduce leaks. Additionally, any of the plurality of the apertures <NUM> may be adjusted in size and number to maximize the surface area of the adhesive <NUM> in fluid communication through the plurality of the apertures <NUM> for a particular application or geometry of the tissue interface <NUM>.

The adhesive <NUM> may be a medically-acceptable adhesive. The adhesive <NUM> may also be flowable. For example, the adhesive <NUM> may comprise an acrylic adhesive, rubber adhesive, high-tack silicone adhesive, polyurethane, or other adhesive substance. In some embodiments, the adhesive <NUM> may be a pressure-sensitive adhesive, such as an acrylic adhesive with coating weight of <NUM> grams/m<NUM> (gsm) to <NUM> grams/m2 (gsm). The adhesive <NUM> may be a layer having substantially the same shape as the periphery <NUM> of the tissue interface <NUM>, and thus have a large central aperture, as shown in <FIG>. In some embodiments, the layer of the adhesive <NUM> may be continuous or discontinuous. Discontinuities in the adhesive <NUM> may be provided by apertures (not shown) in the adhesive <NUM>. Apertures in the adhesive <NUM> may be formed after application of the adhesive <NUM> or by coating the adhesive <NUM> in patterns on a carrier layer, such as, for example, a side of the cover <NUM> adapted to face the epidermis. Further, apertures in the adhesive <NUM> may be sized to control the amount of the adhesive <NUM> extending through the plurality of the apertures <NUM> in the tissue interface <NUM> to reach the epidermis. Apertures in the adhesive <NUM> may also be sized to enhance the Moisture Vapor Transfer Rate (MVTR) of the cover <NUM>, described in further detail below.

Factors that may be utilized to control the adhesion strength of the cover <NUM> may include the diameter and number of the plurality of the apertures <NUM> in the tissue interface <NUM>, the thickness of the tissue interface <NUM>, the thickness and amount of the adhesive <NUM>, and the tackiness of the adhesive <NUM>. An increase in the amount of the adhesive <NUM> extending through the plurality of the apertures <NUM> may correspond to an increase in the adhesion strength of the cover <NUM>. A decrease in the thickness of the tissue interface <NUM> may correspond to an increase in the amount of adhesive <NUM> extending through the plurality of the apertures <NUM>. Thus, the diameter and configuration of the plurality of the apertures <NUM>, the thickness of the tissue interface <NUM>, and the amount and tackiness of the adhesive <NUM> utilized may be varied to provide a desired adhesion strength for the cover <NUM>. For example, in some embodiments, the thickness of the tissue interface <NUM> may be about <NUM> micrometers, the adhesive <NUM> may be a layer having a thickness of about <NUM> micrometers and a tackiness of <NUM> grams per <NUM> centimeter wide strip, and the diameter of the apertures 544a in the tissue interface <NUM> may be about <NUM> millimeters.

Still referring primarily to <FIG>, a release liner <NUM> may be attached to or positioned adjacent to the tissue interface <NUM> to protect the adhesive <NUM> prior to application of the dressing <NUM> to the tissue site. Prior to application of the dressing <NUM> to the tissue site, the tissue interface <NUM> may be positioned between the cover <NUM> and the release liner <NUM>. Removal of the release liner <NUM> may expose the tissue interface <NUM> and the adhesive <NUM> for application of the dressing <NUM> to the tissue site. The release liner <NUM> may also provide stiffness to assist with, for example, deployment of the dressing <NUM>. The release liner <NUM> may be, for example, a casting paper, a film, or polyethylene. Further, the release liner <NUM> may be a polyester material such as polyethylene terephthalate (PET), or similar polar semicrystalline polymer. A release agent may be disposed on a side of the release liner <NUM> that is configured to contact the tissue interface <NUM>. For example, the release agent may be a silicone coating and may have a release factor suitable to facilitate removal of the release liner <NUM> by hand and without damaging or deforming the dressing <NUM>. In some embodiments, the release agent may be fluorosilicone. In other embodiments, the release liner <NUM> may be uncoated or otherwise used without a release agent.

The peripheral portions of the cover <NUM> may be positioned proximate to the periphery <NUM> of the tissue interface <NUM> such that a central portion of the cover <NUM> and the central portion <NUM> of the tissue interface <NUM> define an enclosure. The adhesive <NUM> may be positioned at least between the peripheral portions of the cover <NUM> and the periphery <NUM> of the tissue interface <NUM>. The cover <NUM> may cover the tissue site and the tissue interface <NUM> to provide a fluid seal and a sealed space between the tissue site and the cover <NUM>. Further, the cover <NUM> may cover other tissue, such as a portion of epidermis, surrounding the tissue site to provide the fluid seal between the cover <NUM> and the tissue site. In some embodiments, a portion of the peripheral portion of the cover <NUM> may extend beyond the periphery <NUM> and into direct contact with tissue surrounding the tissue site. In some embodiments, the peripheral portion of the cover <NUM>, for example, may be positioned in contact with tissue surrounding the tissue site to provide the sealed space without the tissue interface <NUM>. Thus, the adhesive <NUM> may also be positioned at least between the peripheral portion of the cover <NUM> and tissue, such as the epidermis, surrounding the tissue site. The adhesive <NUM> may be disposed on a surface of the cover <NUM> adapted to face the tissue site and the tissue interface <NUM>. Additionally, the cover <NUM> may include an aperture <NUM>, which in some embodiments may be generally positioned in a central portion of the cover <NUM>. The aperture <NUM> may allow for fluid communication between a sealed space provided by the cover <NUM> and including a tissue site, and a conduit for conducting negative pressure, such as the bridge <NUM>.

The cover <NUM> may be formed from any material that allows for a fluid seal, such as any of the materials of the cover <NUM>. The cover <NUM> may be vapor permeable and liquid impermeable, thereby allowing vapor and inhibiting liquids from exiting the sealed space provided by the cover <NUM>. In some embodiments, the cover <NUM> may be a flexible, breathable film, membrane, or sheet having a high MVTR and other properties similar to those described with respect to the cover <NUM>. In other embodiments, a low or no vapor transfer drape might be used. In some embodiments, the cover <NUM> may comprise a range of medically suitable films having a thickness between about <NUM> microns (µm) to about <NUM> microns (µm).

The dressing <NUM> may include one or more layers of a manifold material positioned between the tissue interface <NUM> and the cover <NUM>. For example, the dressing <NUM> may include a first manifold layer <NUM> and a second manifold layer <NUM>. In some embodiments, the dressing <NUM> may include additional layers of manifold material, for example, a third manifold layer and a fourth manifold layer. In additional embodiments, the dressing <NUM> may include only one layer of a manifold material. Similarly to the manifold material described with respect to the bridge <NUM> of <FIG>, the manifold material may include a wicking material. Furthermore, the one or more manifold layers may include a non-woven material, such as, for example, a polyester non-woven or Libeltex TDL4 material, and any of the other materials previously discussed with respect to the manifold material of bridge <NUM>. In some embodiments, other non-woven materials may be used for the manifold material, such as Libeltex TDL2 material, or laminations with fiber or foam structures.

The binding layer <NUM> may include a binding material which may demonstrate bacterial-binding as well as protein-binding properties, similar to the binding material of the binding layer <NUM> of the bridge <NUM> discussed above. As depicted in <FIG>, in some embodiments, the binding layer <NUM> may be generally in the form of a sheet and may be positioned between two or more layers of manifold material within the structure of the dressing <NUM>. For example, the binding layer <NUM> may be disposed between the first manifold layer <NUM> and the second manifold layer <NUM>. Similar to the function of the binding layer <NUM> discussed above with respect to <FIG>, the binding layer <NUM> may assist with binding bacteria as well as protein material that may be drawn or wicked out of a tissue site, such as a wound, through components of the dressing <NUM>.

In some embodiments, the dressing <NUM> may include additional components or layers, such as, for example, an absorbent. An example absorbent may comprise or consist of a hydrophilic material adapted to absorb fluid, for example from a tissue site. The absorbent may include, without limitation, any number of individual absorbent components as desired for treating a particular tissue site, including but not limited to superabsorbent materials. For example, the dressing <NUM> may further include a layer of superabsorbent material, which may be positioned between the one or more layers of manifold material, such as the first manifold layer <NUM> and the second manifold layer <NUM>. In some embodiments of the therapy system <NUM>, the container <NUM> may be omitted, and it may be particularly beneficial or necessary to include a structure having absorbent capabilities in the dressing <NUM> or in a fluid conductor of the therapy system <NUM>, such as the bridge <NUM>. The dressing <NUM> may also include other additional layers, such as additional wicking or manifolding layers, based on the specific needs or application of the dressing <NUM>.

As the dressing <NUM> comes into contact with fluid from a tissue site, the fluid may come into contact with the tissue interface <NUM>. The fluid may then pass through the apertures <NUM> of the tissue interface <NUM> toward the first manifold layer <NUM>. The first manifold layer <NUM> may wick or otherwise move the fluid through the tissue interface <NUM> and away from the tissue site. The tissue interface <NUM> may be adapted to transfer fluid away from a tissue site rather than store the fluid. For example, in some embodiments the first manifold layer <NUM> may have a higher affinity for fluid than the tissue interface <NUM>. As fluid, such as wound exudate, is drawn away from a tissue site, the fluid may pass through the tissue interface <NUM> in response to a wicking force generated by the manifold material, such as the first manifold layer <NUM> and the second manifold layer <NUM>, as well as due to the application of negative pressure to the dressing <NUM>. Fluid in the first manifold layer <NUM> and the second manifold layer <NUM> may be drawn against, along, or through the binding layer <NUM>. The binding material of the binding layer <NUM> may bind bacteria and proteins in the fluid, while allowing remaining components of the fluid to continue to pass through the first manifold layer <NUM>, binding layer <NUM>, and second manifold layer <NUM> towards the cover <NUM>. Once the fluid reaches the cover <NUM>, the fluid may be drawn through the aperture <NUM> in the cover <NUM>, out of the dressing <NUM>, and into a fluid conductor, such as a bridge <NUM>, and more specifically the bridge <NUM> of <FIG>. Additionally, vapor may be evaporated through the cover <NUM> and into the environment external to the dressing <NUM>.

Additional embodiments of the therapy system <NUM> may also be provided, in which material for binding bacteria and/or protein may be applied to one or more other components of the therapy system <NUM>, in addition to or instead of the binding layer <NUM> of the bridge <NUM> or the binding layer <NUM> of the dressing <NUM>. In some embodiments of the therapy system <NUM>, instead of introducing an additional binding layer to either the bridge <NUM> or the dressing <NUM>, a binding material, such as a DACC material, as previously discussed, may be applied to or coated on one or more different components or structures of the therapy system <NUM>. For example, a coating of binding material may be applied to one or more components of the dressing <NUM>, such as the tissue interface <NUM>, manifold material, such as the first manifold layer <NUM> and the second manifold layer <NUM>, and an inside surface of the cover <NUM>. A binding material coating may additionally or alternatively be applied to one or more components of the bridge <NUM>, including but not limited to the first sealing layer <NUM> and the second sealing layer <NUM> or the one or more layers of manifold material, such as the first manifold layer <NUM>, the second manifold layer <NUM>, and the third manifold layer <NUM>. The binding material may also be coated on an optional layer of absorbent material which may be included in either or both of the bridge <NUM> or the dressing <NUM>.

Additionally, in some embodiments of the therapy system <NUM>, one or more fluid conductors between the bridge <NUM> and other components of the therapy system <NUM>, such as the negative-pressure source <NUM> or container <NUM>, may be coated on an interior surface with a binding material, such as the DACC material. Coating a fluid conductor with a binding material, such as DACC material, may provide the additional benefit of preventing microorganism growth within fluid that may be in the fluid conductor or stored within the container <NUM>.

Some embodiments of the therapy system <NUM> may also include the use of additional antiseptic materials in addition to or in lieu of the DACC material. For example, one or more layers of either the dressing <NUM> or the bridge <NUM> may be coated or bound with an antiseptic material, such as polyhexanide (PHMB) or activated charcoal. Additionally, the use of inherently "active" antimicrobial materials such as silver, copper, zinc, or titanium, may be appropriate. For example, in addition to or instead of a binding material coating, a coating of antimicrobial material, such as a silver-containing compound, may be applied to any of the above-mentioned layers and components of the bridge <NUM> and dressing <NUM>. In some embodiments, active antimicrobial materials may be included in components of the therapy system <NUM> which are further removed from communication with a tissue site, such as by including the active materials within the bridge <NUM>, so as to minimize any inadvertent effects of active antimicrobial agents to the healing of the tissue site.

The therapy system <NUM> may be supplied as a kit. In some embodiments, a kit may include a dressing <NUM> and a bridge <NUM>. A negative-pressure source <NUM> may also be provided in conjunction with the kit. The dressing <NUM> and the bridge <NUM> may be conveniently applied by a nurse or other caregiver. In some embodiments, the kit may include a bridge <NUM> fluidly pre-connected to a dressing <NUM>. Additionally, a kit may include an interface, such as conduit interface <NUM> and a tubeset that may be supplied attached or unattached to the interface, such as conduit interface <NUM>. In some instances, the tubeset may allow for connection to more than one type of negative-pressure source, such as negative-pressure source <NUM>.

The systems, apparatuses, and methods described herein may provide significant advantages. For example, the therapy system <NUM> may provide a discrete, low-profile, fluid-managing negative-pressure dressing with a bacterial-binding material that can prevent the migration of bacteria back to a tissue site and possible reinfection. Further, incorporating a binding material as part of the bridge <NUM> may be particularly advantageous for retaining any bacterial colonization within the bridge <NUM> and maximizing the distance between bound bacteria and a tissue site. Furthermore, the benefits of including binding materials, such as DACC material, may offer significant benefits associated with binding bacteria and proteins, without incorporating active antimicrobials, such as silver, copper, zinc, or titanium, within the dressing structure that interfaces with a tissue site, and can reduce or minimize side effects of active antimicrobial agents. The therapy system <NUM> also provides for a number of optional configurations, including adding additional functional layers or components to either or both of the dressing <NUM> or bridge <NUM>. A super-absorbent component may further augment the bacterial- and protein-binding potential of the dressing <NUM> and/or bridge <NUM>.

As previously discussed, the incorporation of the binding material into the components of the therapy system <NUM>, such as the dressing <NUM> or bridge <NUM>, may offer significant benefits due to the ability of the binding material to surprisingly bind proteins in wound exudate. Unexpectedly, binding material such as the DACC material, for example the SORBACT product, binds proteins in wound exudate. The binding of the proteins may offer significant improvements to the evaporative and fluid management capabilities of the dressing <NUM> and bridge <NUM>, for example, due to reduction of the potential occlusion by viscous wound exudate caused by the high concentrations of proteins. The binding of proteins in wound exudate by the binding material may help preserve the ability of the other components of a dressing <NUM> or bridge <NUM> to communicate negative pressure and transport fluid. By including the binding material, therapy system <NUM> may be better able to conduct negative pressure to a tissue site as well as transport wound exudate away from a tissue site, even after multiple days of being applied to a tissue site that is exuding highly-viscous fluid. By maintaining good communication of negative pressure within the components of the therapy system <NUM>, such as the dressing <NUM> and the bridge <NUM>, the inclusion of the binding material may help prevent occlusions due to high protein content of viscous wound fluid within the system components and the corresponding pressure drops across different components. For example, the inclusion of the binding material in the binding layer <NUM> of the bridge <NUM> may prevent pressure drops across the length of the bridge <NUM>, which may otherwise occur with the use of multiple layers of low-profile manifold or wicking materials alone, such as the first manifold layer <NUM>, the second manifold layer <NUM>, and the third manifold layer <NUM>. Furthermore, the binding layer <NUM> may offer a lower-profile approach to improve the fluid management capabilities of the bridge <NUM> without adding significant empty volume to the bridge <NUM>, which may otherwise result from previous solutions involving adding more layers of non-woven material or foam to try to improve fluid management and avoid blockages. Thus, the incorporation of the low-profile binding layer <NUM> in the bridge <NUM> may improve fluid management capabilities, without significantly increasing volume in the bridge <NUM> that a mechanical negative-pressure therapy source has to evacuate and maintain at a set level of negative pressure.

As also previously discussed, the therapy system <NUM> can also provide particular advantages for treating some forms of specialized tissue sites, such as ulcers, and more particularly VLUs. VLUs are typically specialized, shallow wounds that occur on the lower leg just above the ankle and tend to affect older patient populations. Current standards of care for treating VLUs often prescribe the use of a simple, non-adherent dressing covered by a compression bandage, with the aim of improving blood flow in the legs of the patient. The dressing and/or compression bandage is often recommended to be changed every seven days by a trained clinician or caregiver. In many instances, the VLU may take anywhere from four to six weeks to heal under such treatment conditions.

It would be advantages, in many cases, to provide VLUs with the benefits of negative-pressure wound therapy to assist with controlling wound exudate, encourage blood flow, and promote healing. However, it may also be important to provide such negative-pressure therapy while allowing the patient to remain ambulatory and maintain a normal lifestyle of day-to-day activities between dressing changes. In fact, in many instances of VLUs, patient mobility is encouraged during treatment to prevent additional patient comorbidities, however this can be challenging given the debilitating nature of VLUs. Thus, considering these factors, it would be beneficial for such a negative-pressure therapy device or system for treatment of VLUs to be lightweight and portable, while also allowing for discrete use in public settings. For example, the negative-pressure source <NUM> may include a negative-pressure therapy device that may be particularly applicable for use with the therapy system <NUM> for treatment of VLUs, such as the SNAP™ Therapy Cartridge, available from Acelity of San Antonio, Texas, or the NANOVA™ Therapy Unit, available from KCI of San Antonio, Texas. Both of these negative-pressure devices may be configured to be highly-portable, mechanical devices without the need for an electrical power source. However, given the small size and portability of such negative-pressure therapy devices, it may be particularly important to pair these devices with one or more dressing and/or system components that are designed for minimizing pressure differentials or drops for managing fluid properly and efficiently. For example, components of the dressing <NUM>, as well as components in the fluid conductors of the therapy system <NUM>, such as the bridge <NUM>, may be incorporated to reduce or prevent occlusions or blockages in order to maintain continuous transmission of negative pressure through the therapy system <NUM>.

Depending on the particular type of negative-pressure source <NUM> included in the therapy system <NUM>, different combinations and variations of the dressing <NUM> and the bridge <NUM> may be incorporated into the therapy system <NUM>. For example, in embodiments of the therapy system <NUM> that include a SNAP™ cartridge, it may be beneficial to use both a dressing <NUM> and bridge <NUM> that both omit a separate absorbent layer, such as the absorbent layer <NUM> of <FIG>. In other embodiments of the therapy system <NUM> that include a NANOVA™ unit, either or both of the dressing <NUM> and bridge <NUM> may incorporate an absorbent layer, such as the absorbent layer <NUM> of <FIG>.

Moreover, distribution components such as the dressing <NUM> and the bridge <NUM> may have a low profile for discrete use with a shallow wound such as a VLU, and can minimize pressure drops. The dressing <NUM> and the bridge <NUM> may enable the use of a lightweight, portable negative-pressure therapy device, such as a SNAP™ cartridge or NANOVA™ unit, for providing the required level of negative pressure to a tissue site for an extended period. The dressing <NUM> may also have a low-profile suitable for use under a compression garment. Thus, some embodiments of the dressing <NUM> and the bridge <NUM> may be particularly suitable for use with a <NUM>-day compression bandage treatment regime for VLUs. The compression garment, bandage, or stocking may either be used to cover both the bridge <NUM> and the dressing <NUM> or just the dressing <NUM> itself. Depending on the particular application, the compression garment, bandage, or stocking should also be breathable so as not to prevent the exchange of air flow with the bridge <NUM> and/or dressing <NUM> that may be required to allow the bridge <NUM> and/or dressing <NUM> to provide the beneficial fluid management and vapor evaporation functionalities. The compression garment may also contain an antimicrobial element. The dressing <NUM> and the bridge <NUM>, due to the incorporation of a binding material, should also be capable of effectively mitigating and combating the propensity for bacterial growth that can occur in dressings worn for longer durations, such as those worn for up to <NUM> days.

Beneficial effects of incorporating the binding material in one or more components of the therapy system <NUM> may be illustrated in part by <FIG>. For example, <FIG> provides a chart comparing the performance of two different bridge dressings at minimizing pressure drops across each of the bridge dressings. Each of the bridge dressings was applied to a simulated tissue site and subjected to a seven day test period during which fluid was instilled, in order to simulate conditions of wound exudates at a tissue site. A first bridge dressing included in the experiment, designated as Dressing <NUM>, included one binding layer comprising binding material disposed between three layers of wicking material, which in this instance were three layers of Libeltex TDL2 80gsm material. The binding layer of Dressing <NUM> included an acetate fabric impregnated with DACC with an enclosed gauze layer, such as the Cutimed® Sorbact® product. A second bridge dressing in the experiment, designated as Dressing <NUM>, included four layers of wicking material, which were also the Libeltex TDL2 80gsm material. Dressing <NUM> did not include a binding layer.

The two dressings, Dressing <NUM> and Dressing <NUM>, were each tested according to a protocol where simulated wound fluid having a viscosity of approximately <NUM> mPa·s was instilled to a simulated wound over a period of <NUM> days. The simulated wound fluid was applied using a calibrated syringe driver. The flow rate of the simulated wound fluid on Day <NUM> was <NUM> / <NUM> hours, and the flow rate for Days <NUM>-<NUM> was <NUM> / <NUM> hours. The <NUM> mPa·s simulated wound fluid included the components as listed in Table <NUM>, below.

Each of Dressing <NUM> and Dressing <NUM> was incorporated within a simulated therapy system to model the therapy system <NUM>, where each simulated system included at least a dressing for placing over the simulated wound, a low-profile conduit or bridge dressing (Dressing <NUM> or Dressing <NUM>), and a negative-pressure source. Any additional connectors, interfaces, or tubing necessary to complete the simulated therapy system were used consistently between the two systems testing Dressing <NUM> and Dressing <NUM>. Negative pressure was applied by the same form of negative-pressure source capable of delivering a consistent amount of negative pressure at the pump, which may otherwise be referred to as the pump pressure. For example, in this experiment, an INFOV. ™ Therapy Unit, commercially available from KCI of San Antonio, TX, was used to generate negative pressure at a constant -125mmHg. The negative pressure was delivered at -<NUM> mmHg for a constant <NUM>-day period. During this <NUM>-day test period, pressure measurements, such as the pressure differential across each of the lengths of the two tested bridge dressings, Dressing <NUM> and Dressing <NUM>, were measured at standard time intervals, taking instantaneous measurements. In this experiment, the pressure differential across the length of each bridge dressing was determined by subtracting the pressure level measured at the simulated wound from the pump pressure which in this instance was set to a controlled negative pressure of - <NUM> mmHg (Pressure Differential = Pump Pressure - Wound Pressure).

As evident from the chart of <FIG>, there is a notable reduction in pressure differential, and thus improvement in the ability to communicate negative pressure, of Dressing <NUM> as compared to Dressing <NUM>. Results indicated that the average pressure drop or differential, which may be considered in absolute values, was only <NUM> mmHg (Std. of <NUM>) over the <NUM>-day period for Dressing <NUM>, which included the binding layer of Cutimed® Sorbact® DACC material sandwiched between the three layers of Libeltex TDL2 80gsm material. In contrast, the average pressure drop was <NUM> mmHg (Std. of <NUM>) over the same <NUM>-day period for Dressing <NUM>, which included the four layers of Libeltex TDL2 80gsm material, and no binding layer. Thus, an approximate <NUM>% difference in pressure drop was realized between Dressing <NUM> and Dressing <NUM>, which can be attributed to the inclusion of the binding layer in Dressing <NUM>.

<FIG> includes a chart, similar to that of <FIG>, showing the results of an experiment comparing the performance of two different bridge dressings. However, in the experiment of <FIG>, the two tested bridge dressings were tested using simulated wound fluid having a significantly higher viscosity of approximately <NUM> mPa·s. The first bridge dressing included in the experiment of <FIG>, designated as Dressing <NUM>, included one binding layer of Cutimed® Sorbact® material sandwiched between three layers of manifold material, which in this instance were three layers of Libeltex TDL2 80gsm material. The second bridge dressing in this experiment, designated as Dressing <NUM>, included four layers of manifold material, once again the Libeltex TDL2 80gsm material. Dressing <NUM> did not include a binding layer.

Once again, the two dressings, Dressing <NUM> and Dressing <NUM>, were tested according to the same testing protocols as the experiment of Dressing <NUM> and Dressing <NUM>, as described in relation to <FIG>. However, as already noted, the simulated wound fluid in the experiment of <FIG> had a viscosity of approximately <NUM> mPa·s, as compared to the simulated wound fluid of the experiment of <FIG>, which had a viscosity of approximately <NUM> mPa·s. To achieve the higher viscosity of approximately <NUM> mPa·s, the simulated wound fluid of the experiment of <FIG> was prepared with a greater amount of the albumin protein and Cosmedia (thickening agent) components. The <NUM> mPa·s simulated wound fluid included the components as listed in Table <NUM>, below.

As shown in the chart of <FIG>, a significant reduction in pressure differential of Dressing <NUM> is seen as compared to Dressing <NUM>, which does not include the binding layer, but rather only manifold layers. More specifically, the average pressure drop was <NUM> mmHg (Std. of <NUM>) over the <NUM>-day test period for Dressing <NUM>, as opposed to the average pressure drop of <NUM> mmHg (Std. of <NUM>) for Dressing <NUM>. Accordingly, an approximate <NUM>% difference in pressure drop was realized between the two tested dressings, which can be attributed to the inclusion of the binding layer in Dressing <NUM>. Thus, the benefits and performance improvement due to the inclusion of a binding layer can be especially realized in the context of tissue sites or wounds that exude fluid having a high viscosity, such as some VLUs, which may often be due to a high protein concentration. Furthermore, the average pressure drop of <NUM> mmHg for Dressing <NUM> would likely be considered a test failure according to current testing standards for some therapy systems using certain negative-pressure sources. For example, testing standards for some therapy systems permit a maximum average pressure drop across dressing and/or system components of no more than <NUM> mmHg. Therefore, the inclusion of a binding layer of bacterial-binding material, such as that of Dressing <NUM> and Dressing <NUM>, may offer considerable benefits for use with mechanically-driven sources of negative-pressure which may have lower tolerances for pressure drops.

<FIG> includes a chart, similar to those of <FIG> and <FIG>, comparing the results of Dressing <NUM>, which was subjected to the <NUM> mPa·s simulated wound fluid, and Dressing <NUM>, which was subjected to the <NUM> mPa·s simulated wound fluid. Given that each of Dressing <NUM> and Dressing <NUM> had the same structure and included one binding layer of Cutimed® Sorbact® DACC material sandwiched between three layers of manifold material, which were three layers of Libeltex TDL2 80gsm material, the effects of varied simulated wound fluid viscosity can be observed. The two dressings, Dressing <NUM> and Dressing <NUM>, were tested according to the same testing protocols as the experiments of <FIG> and <FIG>. As shown in the chart of <FIG>, the average pressure drop for Dressing <NUM>, which was subjected to the <NUM> mPa·s simulated wound fluid, was <NUM> mmHg as compared to the average pressure drop of <NUM> mmHg for Dressing <NUM>, which was subjected to the <NUM> mPa·s simulated wound fluid.

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 one or more of the negative-pressure source <NUM>, the dressing <NUM>, and the container <NUM> may be separated from other components for manufacture or sale. In other example configurations, the controller <NUM> may also be manufactured, configured, assembled, or sold independently of other components.

Claim 1:
An apparatus for treating a tissue site, comprising:
a dressing (<NUM>, <NUM>); and
a bridge (<NUM>, <NUM>) adapted to be fluidly coupled to the dressing (<NUM>, <NUM>), the bridge (<NUM>, <NUM>) comprising:
a first manifold layer (<NUM>),
a second manifold layer (<NUM>),
a binding layer (<NUM>) comprising a binding material positioned between the first manifold layer (<NUM>) and the second manifold layer (<NUM>), wherein the binding material has bacterial-binding and protein-binding properties and
a sealing material having a first end (<NUM>) and a second end (<NUM>), wherein the first end (<NUM>) comprises a first aperture (<NUM>) adapted to be fluidly coupled to a negative-pressure source, and the second end (<NUM>) comprises a second aperture (<NUM>) adapted to be fluidly coupled to the dressing (<NUM>, <NUM>);
wherein the first manifold layer (<NUM>), the second manifold layer (<NUM>), and the binding layer (<NUM>) are enclosed within the sealing material and are fluidly coupled between the first and second apertures (<NUM>, <NUM>).