Patent Description:
Treatment of wounds or other tissue with reduced pressure may be commonly referred to as "negative-pressure therapy," but is also known by other names, including "negative- pressure wound therapy," "reduced-pressure therapy," "vacuum therapy," "vacuum-assisted closure," and "topical negative-pressure," for example. Reduced-pressure therapy may provide a number of benefits, including migration of epithelial and subcutaneous tissues, improved blood flow, and micro- deformation of tissue at a wound site.

While the clinical benefits of negative-pressure therapy are widely known, improvements to therapy systems, components, and processes may benefit healthcare providers and patients. <CIT> discloses a negative pressure wound dressing for use with breast incisions. <CIT> discloses a system for providing negative-pressure to breast tissue.

The invention is defined by the independent claim. A selection of optional features is set out in the dependent claims.

The following detailed description is, therefore, to be taken as illustrative and non-limiting.

<FIG> is a 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 may refer 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, grafts, and incisions, 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 reduced or 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 one or more sensors coupled to the controller <NUM>, such as a first sensor <NUM> and a second sensor <NUM>. As illustrated in the example of <FIG>, the dressing <NUM> may include a tissue interface <NUM>, a cover <NUM>, or both in some embodiments. The dressing <NUM> may also be referred to as a dressing assembly in some examples, which may include additional or different features as described herein.

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 may be 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, may include a tube, pipe, hose, conduit, or other structure with one or more lumina or open pathways adapted to convey a fluid between two ends. Distribution components may also include interfaces or fluid ports to facilitate coupling and de-coupling other components. ™ Pad 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 reduced 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" or "reduced 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. Further, 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 reduced pressure may refer to a decrease in absolute pressure, while decreases in reduced pressure may refer to an increase in absolute pressure. While the amount and nature of reduced 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).

In some embodiments, for example, the controller <NUM> may be a microcontroller, which may include an integrated circuit containing a processor core and a memory programmed to directly or indirectly control one or more operating parameters of the therapy system <NUM>. The controller <NUM> may also be configured to receive one or more input signals, such as a feedback signal, and programmed to modify one or more operating parameters based on the input signals.

Sensors, such as the first sensor <NUM> and the second sensor <NUM>, may be 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. In some embodiments, for example, the first sensor <NUM> may be a piezoresistive strain gauge. The second sensor <NUM> may optionally measure operating parameters of the negative-pressure source <NUM>, such as the voltage or current, in some embodiments. Signals from the first sensor <NUM> and the second sensor <NUM> may be 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 adapted to partially or fully contact a tissue site. 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 be a manifold or may include a manifold and additional layers, such as a tissue contact layer, depending on the desired treatment. A "manifold" in this context may include any substance or structure providing a plurality of pathways adapted to collect or distribute fluid relative to a tissue. For example, a manifold may be adapted to receive reduced pressure from a source and distribute reduced pressure through multiple apertures to or from a tissue site, which may have the effect of collecting fluid from 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 or moving fluid relative to a tissue site.

In some illustrative embodiments, the pathways of a manifold may be interconnected to improve distribution or collection of fluids at a tissue site. In some illustrative embodiments, a manifold may be a porous foam material having interconnected cells or pores. For example, open-cell foam, porous tissue collections, and other porous material such as gauze or felted mat generally include pores, edges, and/or walls adapted to form interconnected fluid channels. Liquids, gels, and other foams may also include or be cured to include apertures and fluid pathways. In some embodiments, a manifold may additionally or alternatively include projections that form interconnected fluid pathways. For example, a manifold may be molded to provide surface projections that define interconnected fluid pathways.

The average pore size of foam may vary according to needs of a prescribed therapy. For example, in some embodiments, the tissue interface <NUM> may be foam having pore sizes in a range of <NUM>-<NUM> microns. The tensile strength of the tissue interface <NUM> may also vary according to needs of a prescribed therapy. For example, the tensile strength of foam may be increased for instillation of topical treatment solutions. In some examples, the tissue interface <NUM> may be reticulated polyurethane foam such as found in GRANUFOAM™ dressing or V. VERAFLO™ dressing, both available from KCI of San Antonio, Texas.

The tissue interface <NUM> may be either hydrophobic or hydrophilic. In an example in which the tissue interface <NUM> may be hydrophilic, 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. An example of hydrophilic foam is a polyvinyl alcohol, open-cell foam such as V. WHITEFOAM™ dressing available from KCI of San Antonio, Texas. Other hydrophilic foams may include those made from polyether. Other foams that may exhibit hydrophilic characteristics include hydrophobic foams that have been treated or coated to provide hydrophilicity.

The tissue interface <NUM> may further promote granulation at a tissue site when pressure within the sealed therapeutic environment is reduced. For example, any or all of the surfaces of the tissue interface <NUM> may have an uneven, coarse, or jagged profile that can induce microstrain and stress at a tissue site if negative pressure is applied through the tissue interface <NUM>.

In some embodiments, the tissue interface <NUM> may be constructed from bioresorbable materials. Suitable bioresorbable materials may include, without limitation, a polymeric blend of polylactic acid (PLA) and polyglycolic acid (PGA). The polymeric blend may also include without limitation polycarbonates, polyfumarates, and capralactones. The tissue interface <NUM> may further serve as a scaffold for new cell-growth, or a scaffold material may be used in conjunction with the tissue interface <NUM> to promote cell-growth. A scaffold is generally a substance or structure used to enhance or promote the growth of cells or formation of tissue, such as a three-dimensional porous structure that provides a template for cell growth. Illustrative examples of scaffold materials include calcium phosphate, collagen, PLA/PGA, coral hydroxy apatites, carbonates, or processed allograft materials.

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. For example, the cover <NUM> may comprise or consist essentially of an elastomeric film or membrane that can provide a seal adequate to maintain a reduced pressure at a tissue site for a given negative-pressure source. 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. 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 in some embodiments (based on ASTM E96/E96M for upright cup measurement). 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. In some embodiments, the cover <NUM> may form an outer surface of the dressing <NUM>.

An attachment device may be used to attach the cover <NUM> to an attachment surface, such as undamaged epidermis, a gasket, or another cover (e.g. at the tissue site). 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> grams per square meter (g. 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.

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

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

<FIG> is a graph illustrating additional details that may be associated with another example pressure control mode in some embodiments of the therapy system <NUM>. In <FIG>, the x-axis represents time and the y-axis represents negative pressure generated by the negative-pressure source <NUM>. The target pressure in the example of <FIG> can vary with time in a dynamic pressure mode. For example, the target pressure may vary in the form of a triangular waveform, varying between a minimum and maximum reduced pressure of <NUM>-<NUM> mmHg with a rise time <NUM> set at a rate of +<NUM> mmHg/min. and a descent time <NUM> set at -<NUM> mmHg/min, respectively. In other embodiments of the therapy system <NUM>, the triangular waveform may vary between reduced pressure of <NUM>-<NUM> mmHg with a rise time <NUM> set at a rate of +<NUM> mmHg/min and a descent time <NUM> set at -<NUM> mmHg/min.

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

Referring to <FIG>, the dressing <NUM> may include features that can treat a tissue site, such as a patient's breast, or parts thereof, and an area of tissue around the tissue/treatment site. For example, the tissue site may be an incision or other treatment target on a patient. The dressing <NUM> may be configured to treat not only the incision or treatment target, but also, an area of tissue around the incision or treatment target. While the figures may illustrate exemplary dressing embodiments as configured for use on a breast tissue site, other exemplary dressings may have other sizes, shapes, and/or configurations, for example for use on other tissue sites.

<FIG> is an exploded, isometric view of an example embodiment of a dressing that may be associated with an example embodiment of the therapy system of <FIG>. Referring more specifically to <FIG>, in some examples, the dressing <NUM> may include an attachment device <NUM>, a manifold <NUM>, and the cover <NUM>. Some examples of the attachment device <NUM> and other components may include a treatment aperture <NUM>, and the manifold <NUM> may be configured to be at least partially exposed to a tissue site through the treatment aperture <NUM>. Further, in some examples, the dressing <NUM> may optionally include an adhesive ring <NUM> that may be configured to bond a peripheral portion of the manifold <NUM> to a portion of the attachment device <NUM>. In some examples, the adhesive ring <NUM> may be formed as part of the attachment device <NUM>, or the adhesive ring <NUM> may be omitted with the attachment device <NUM> instead being coupled to the manifold <NUM> and/or cover <NUM> with another medically acceptable coupling apparatus. In some examples, the cover <NUM>, the manifold <NUM>, the optional adhesive ring <NUM>, and the attachment device <NUM> may have similar shapes. The attachment device <NUM> may be slightly larger than the manifold <NUM> to permit coupling of the attachment device <NUM> to the cover <NUM> around the manifold <NUM>. In some examples, an adhesive may be disposed on a portion of the manifold <NUM> exposed through the treatment aperture <NUM>. In some embodiments, the adhesive may be pattern-coated, and may cover up to <NUM>% of the exposed portion or surface of the manifold <NUM>.

The cover <NUM>, the manifold <NUM>, the attachment device <NUM>, or various combinations may be assembled before application or at a tissue site. In some embodiments, the dressing <NUM> may be provided as a single unit.

The manifold <NUM> may include a first surface <NUM> and an opposing second surface <NUM>. In some examples, at least a portion of the second surface <NUM> (e.g. the tissue-facing surface) of the manifold <NUM> may be configured to face the tissue site (e.g. the area of tissue around the extremity) through the treatment aperture <NUM>. In some examples, the attachment device <NUM> may be positioned on or at a portion of the second surface <NUM> of the manifold <NUM>. In some examples, the manifold <NUM> may include or be formed of a porous material, such as foam.

In some examples, the attachment device <NUM> may be configured to create a sealed space between the cover <NUM> and the tissue site, and the manifold <NUM> may be configured to be positioned in the sealed space. For example, the attachment device <NUM> may be positioned around an edge <NUM> of the manifold <NUM> and configured to surround the tissue site. The cover <NUM> may be disposed over the manifold <NUM> and coupled to the attachment device <NUM> around the manifold <NUM>. For example, the cover <NUM> may be coupled to a portion of the attachment device <NUM> extending outward from the edge <NUM> of the manifold <NUM>. Further, the cover <NUM> may be larger than the manifold <NUM>, as illustrated in the example of <FIG>, and may have a perimeter or a flange <NUM> configured to be attached to the attachment device <NUM>. Assembled, the cover <NUM> may be disposed over the first surface <NUM> (e.g. the outward-facing surface) of the manifold <NUM>, and the flange <NUM> may be attached to the attachment device <NUM> around the manifold <NUM>. For example, an adhesive may be used to adhere the flange <NUM> to the attachment device <NUM>, or the flange <NUM> may be, without limitation, welded, stitched, or stapled to the attachment device <NUM>. In some embodiments, the attachment device may comprise an adhesive applied to the flange <NUM> and configured to allow attachment of the flange <NUM> to the tissue site. The cover <NUM> may also include a port <NUM> configured to allow fluid communication between the manifold <NUM> and a dressing interface <NUM> and/or a fluid conductor <NUM> (e.g. to apply negative pressure under the cover) as described herein.

The attachment device <NUM> may take many forms. In some examples, the attachment device <NUM> may include or be formed of a film or membrane that can provide a seal in a therapeutic negative-pressure environment. In some example embodiments, the attachment device <NUM> may be a polymer film, such as a polyurethane film, that is permeable to water vapor but impermeable to liquid. The attachment device <NUM> may have a thickness in the range of <NUM>-<NUM> microns. For permeable materials, the permeability may be low enough that a desired reduced pressure may be maintained. The attachment device <NUM> may also include a medically-acceptable adhesive, such as a pressure-sensitive adhesive. In examples, the attachment device <NUM> may be a polymer film coated with an adhesive, such as an acrylic adhesive, which may have a coating weight between <NUM>-<NUM> grams per square meter (g. Thicker adhesives, or combinations of adhesives, may be applied in some examples to improve the seal and reduce leaks.

In some examples, the attachment device <NUM> may include or be formed of a hydrocolloid. In some examples, the attachment device <NUM> may be configured or referred to as a sealing ring or a gasket member. In other examples, the dressing <NUM> may include a gasket member (not shown) in addition to the attachment device <NUM>. In such an example, the gasket member may be a peripheral member, such as a hydrocolloid ring, and at least a portion of the attachment device <NUM> may be positioned between the manifold <NUM> and the gasket member on or at a surface of the manifold <NUM>, such as the second surface <NUM>, configured to face the area of tissue around the tissue site. In some examples, the gasket member may have a similar or analogous shape as the adhesive ring <NUM>, but the gasket member may be positioned on a surface of the attachment device <NUM> configured to face the tissue site such that the gasket member is configured to be positioned between the tissue site and the attachment device <NUM>.

In some examples, the dressing <NUM> may optionally further include a tissue contact layer <NUM>, which may be coupled to a surface of the manifold <NUM>, such as the second surface <NUM>, and may be configured to be exposed to the tissue site. In some embodiments, the tissue contact layer <NUM> may be configured to be positioned in direct contact with the tissue site, for example forming a tissue-contact surface. In other embodiments (e.g. without a tissue-contact layer), the tissue-contact surface may be formed by the manifold and/or the attachment device. The tissue contact layer <NUM> may include or be formed of a material that substantially reduces or eliminates skin irritation while allowing fluid transfer through the tissue contact layer. In some embodiments, the tissue contact layer <NUM> may form a fluid control layer, configured to allow fluid communication between the tissue site and the manifold during negative-pressure therapy, while minimizing backflow of fluids (such as exudate) from the manifold to the tissue site (e.g. to minimize maceration). In some examples, the tissue contact layer <NUM> may include or be formed of one or more of the following materials, without limitation: a woven material, a non-woven material, a polyester knit material, and a fenestrated film.

In some examples, the attachment device <NUM>, which may comprise an adhesive on a surface of the dressing <NUM> configured to face the tissue site (e.g. on the tissue-contact surface), may be covered by one or more release liners <NUM> prior to applying the dressing <NUM> at the tissue site. For example, as shown in <FIG>, the dressing <NUM> may include a first release liner 428a, a second release liner 428b, and a third release liner 428c. The first release liner 428a may be positioned proximate to a first side <NUM> of the manifold <NUM> or the dressing <NUM>, the second release liner 428b may be positioned proximate to a second side <NUM> of the manifold <NUM> or the dressing <NUM> (e.g. with the first side <NUM> and the second side <NUM> opposite each other across a line of symmetry), and the third release liner 428c may be positioned proximate to a fold axis, centerline, or line or symmetry of the manifold <NUM> or the dressing <NUM> (e.g. spanning a central portion of the manifold and/or dressing). The central portion with the line of symmetry may be located between the first side <NUM> and the second side <NUM>, and the third release liner 428c may be positioned between the first release liner 428a and the second release liner 428b. In some examples, the third release liner 428c may be configured to be removed to expose an adhesive or portion of the attachment device <NUM> proximate to the line of symmetry prior to removal of the first release liner 428a and the second release liner 428b. Such a configuration may permit the central portion of the dressing <NUM> (e.g. in proximity to the line of symmetry) to be initially positioned or aligned at a tissue site, such as the extremity, while the first release liner 428a and the second release liner 428b protect other portions of the adhesive or the attachment device <NUM>. For example, a portion of the third release liner 428c may cover or be positioned over a portion of the first release liner 428a and/or the second release liner 428b such that the third release liner 428c may be removed prior to removal of the first release liner 428a and the second release liner 428b. In some examples, the dressing <NUM> may have two release liners, each of which may have perforations or slits (not shown here) configured to allow the release liners to be separated into smaller pieces for removal. Additionally, some embodiments may also have one or more casting sheet liners <NUM>.

Additionally or alternatively, the first release liner 428a, the second release liner 428b, and the third release liner 428c may provide stiffness to the attachment device <NUM> to facilitate handling and application. Additionally or alternatively, the casting sheet liners <NUM> may cover the flange <NUM> to provide stiffness to the cover <NUM> for handling and application. The one or more release liner <NUM> may be configured to releasably cover the attachment device <NUM>, for example to protect and maintain the adhesive of the attachment device <NUM> until the time of application of the dressing <NUM> to the tissue site.

In some examples, the dressing <NUM> may include the dressing interface <NUM>, which may be fluidly coupled to the manifold <NUM> through the port <NUM> in the cover <NUM>. In some embodiments, the dressing interface <NUM> may be coupled in the central portion of the manifold <NUM> (e.g. in proximity to the line of symmetry), and may be configured to be coupled to the negative-pressure source through, for example, the fluid conductor <NUM>, conduit, or tube coupled in fluid communication between the dressing interface <NUM> and the reduced pressure source <NUM>.

<FIG> is a schematic view illustrating an exemplary system having the dressing <NUM> of <FIG> in place on an exemplary tissue site, illustrating additional details that may be associated with some embodiments. The system <NUM> may comprise a negative-pressure source <NUM> in fluid communication with the dressing <NUM>. For example, the dressing <NUM> may comprise a dressing interface <NUM>, which may penetrate the cover of the dressing <NUM> to fluidly couple to the manifold of the dressing <NUM>, and a fluid conductor <NUM> may fluidly couple the negative-pressure source <NUM> to the dressing interface <NUM> (thereby fluidly coupling the negative-pressure source <NUM> to the manifold of the dressing <NUM>, for application of negative-pressure therapy to the tissue site through the manifold of the dressing <NUM>). In <FIG>, the tissue site is shown as a breast of a patient, and the dressing <NUM> may be coupled to the breast.

In operation, the negative-pressure source <NUM> can reduce pressure in the sealed therapeutic environment (e.g. when the dressing <NUM> is applied to the tissue site in the usage configuration). Reduced pressure applied to the tissue site through the manifold <NUM> in the sealed therapeutic environment can induce macro-strain and micro-strain in the tissue site, as well as remove exudates and other fluids from the tissue site, which can be collected in the container <NUM>.

In general, exudates and other fluids flow toward lower pressure along a fluid path. Thus, the term "downstream" may refer to a location in a fluid path relatively closer to a source of reduced pressure or further away from a source of positive pressure. Conversely, the term "upstream" may refer to a location further away from a source of reduced pressure or closer to a source of positive pressure.

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

Some dressing <NUM> embodiments may be configured to provide multiple, different pressure zones to a tissue site. For example, some dressing <NUM> embodiments may have two zones: a negative-pressure zone, and an isolated zone (such as a zone of ambient pressure). The two zones may be fluidly isolated from each other, with no fluid communication therebetween. In some embodiments, the negative-pressure zone may be configured to surround the isolated zone on the tissue site. In some embodiments, the isolated zone may be configured to lie within (e.g. underlie) the negative-pressure zone (e.g. located between a portion of the tissue site and the negative-pressure zone). The negative-pressure zone may be configured to provide negative-pressure therapy to the tissue site. The isolated zone may be configured to have a pressure different than that of the negative-pressure zone. For example, the isolated zone may be configured to shield a portion of the tissue site from the negative pressure and/or to maintain ambient pressure at the portion of the tissue site. In addition to maintaining ambient pressure and/or blocking the negative-pressure while surrounded by the negative-pressure zone, the isolated zone may also be configured to resist appositional and/or decompressive forces resulting from the negative pressure in the negative-pressure zone during negative-pressure therapy.

<FIG> is an exploded, isometric view of another example embodiment of a dressing <NUM> that may be associated with an example embodiment of the therapy system of <FIG>. The dressing <NUM> of <FIG> may be configured with two exemplary pressure zones. In some embodiments, the dressing <NUM> of <FIG> may comprise two parts: a negative-pressure dressing <NUM> and an isolation patch <NUM>, such as a zone of ambient pressure (ZAP) patch. The negative-pressure dressing <NUM> may be configured to form the negative-pressure zone (e.g. when attached to the tissue site), and the isolation patch <NUM> may be configured to form the isolated zone (e.g. when attached to a portion of the tissue site and/or under the negative-pressure dressing). In some embodiments, the two-part dressing <NUM> may form a dressing assembly. In some embodiments, the negative-pressure dressing <NUM> may be similar to the dressing in <FIG>, and may be configured to overlie the isolation patch <NUM>. In use, the isolation patch <NUM> may be configured to underlie the negative-pressure dressing <NUM>, for example located between the portion of the tissue site and the negative-pressure dressing <NUM>. When used together as a dressing assembly, the negative-pressure dressing <NUM> and the isolation patch <NUM> may allow for application of negative-pressure therapy to a tissue site generally, except for a portion of the tissue site (covered by the isolation patch <NUM>) which may be isolated and/or shielded from the negative pressure. In some embodiments, the isolation patch <NUM> may be configured to isolate the portion of the tissue site from the negative pressure of the negative-pressure zone, to prevent infiltration of the negative pressure from the negative-pressure zone into the isolated zone formed by the isolated patch <NUM> on the portion of the tissue site, to prevent fluid communication between the isolated zone and the negative-pressure zone, to maintain ambient pressure at the portion of the tissue site, to prevent or minimize pressure changes at the portion of the tissue site covered by the isolation patch <NUM>, to allow a pressure different than that of the negative-pressure zone to be applied to or maintained at the portion of the tissue site in the isolated zone, and/or to exclude the negative pressure from the portion of the tissue site. In some embodiments, the isolation patch <NUM> may be configured to resist, reduce, and/or minimize appositional and/or decompressive forces (e.g. from negative-pressure therapy under the negative-pressure dressing <NUM>) on the portion of the tissue site.

<FIG> is a top plan view of the isolation patch <NUM> portion of the dressing of <FIG>, illustrating additional details that may be associated with some embodiments. As shown in <FIG>, the isolation patch <NUM> may be vented, for example with a ventilation conduit <NUM> configured to fluidly couple the isolation patch <NUM> to an ambient environment outside of the negative-pressure dressing. The vent of the isolation patch <NUM> may be configured to fluidly couple the isolation patch <NUM> (e.g. a patch manifold) to the ambient environment. In some embodiments, the isolation patch <NUM> may have a length of <NUM> or less. In some embodiments, the isolation patch <NUM> may be sized approximately <NUM> by <NUM> or have a diameter of approximately <NUM>. In some embodiments, the isolation patch <NUM> may have dimensions (e.g. length and width, or diameter) from approximately <NUM> - <NUM>, <NUM> - <NUM>, or <NUM> - <NUM>. In some embodiments, the negative-pressure dressing <NUM> may have dimensions of approximately <NUM> by <NUM>, <NUM> by <NUM>, or <NUM> by <NUM>. In some embodiments, the ratio of the surface area of the negative-pressure dressing <NUM> to the surface area of the isolation patch <NUM> may be from about <NUM>:<NUM> to <NUM>:<NUM>.

<FIG> is an exploded isometric view of the isolation patch <NUM> of <FIG>, illustrating additional details that may be associated with some embodiments. In some embodiments, the isolation patch <NUM> may comprise or consist essentially of a force-dissipating pad, which may be configured to dissipate or isolate the portion of the tissue site from forces that may be associated with the negative pressure, such as appositional, compressive, or contractive forces for example. For example, the force-dissipating pad in <FIG> may comprise a patch manifold <NUM>. In some embodiments, the patch manifold <NUM> may be similar to the manifold <NUM> described above (e.g. of the negative-pressure dressing). In some embodiments, the patch manifold <NUM> may comprise open-cell and/or reticulated foam, such as polyurethane foam. The patch manifold <NUM> may have a thickness of about <NUM>-<NUM>, in some embodiments, for example about <NUM>, about <NUM>, or about <NUM>. The isolation patch <NUM> may also comprise a patch cover <NUM>, which may be configured to be disposed over the patch manifold <NUM> (e.g. opposite the tissue site) and which may be formed of material that substantially prevents and/or restricts fluid flow therethrough and/or provides a fluid seal adequate to maintain a reduced pressure at the tissue site for a given negative-pressure source. For example, the patch cover <NUM> may be occlusive. In some embodiments, the patch cover <NUM> may also have a high MVTR, such as greater than <NUM>/m<NUM>/24hours. In some embodiments, the patch cover <NUM> may be similar to the cover <NUM> described above (e.g. with respect to the negative-pressure dressing). In some embodiments, the patch cover may comprise polyurethane film. The patch cover <NUM> may comprise a vent opening, in some embodiments, allowing fluid communication between the ventilation conduit <NUM> and the patch manifold <NUM>, but may otherwise be configured to prevent fluid flow therethrough. In some embodiments, the patch cover <NUM> may be coupled to the patch manifold <NUM> (e.g. on an outward-facing side of the patch manifold <NUM>) and/or may form an outer surface of the isolation patch <NUM>. Some embodiments of the isolation patch <NUM> may further comprise an optional patch tissue contact layer <NUM> (e.g. similar to the tissue contact layer <NUM> which may be used for the negative-pressure dressing). The patch tissue contact layer <NUM> may be coupled to the patch manifold <NUM>, for example opposite the patch cover <NUM>, in some embodiments, and/or may be configured to allow fluid communication from the tissue site to the patch manifold <NUM>. In some embodiments, the patch tissue contact layer <NUM> may form the tissue-contact surface of the isolation patch <NUM>, configured to directly contact the portion of the tissue site. In some embodiments, the patch tissue contact layer <NUM> may comprise one or more of the following: a woven material, a non-woven material, a polyester knit material, and a fenestrated film. Some embodiments of the isolation patch <NUM> may further comprise a patch attachment device (not shown here, which may be similar to the attachment device of the negative-pressure dressing <NUM>), which may be configured to attach the patch cover <NUM> to the isolated portion of the tissue site (e.g. located around the inward-facing surface of the patch manifold <NUM> and/or the patch tissue contact layer <NUM> of the isolation patch) and to form a seal around the perimeter of the portion of the tissue site, preventing fluid communication between the isolated portion of the tissue site and the negative-pressure zone under the negative-pressure dressing. Some embodiments of the isolation patch <NUM> may further comprise one or more patch release liner <NUM> (e.g. similar to the release liner(s) <NUM> for the negative-pressure dressing), which may releasably cover the patch attachment device of the isolation patch. In some embodiments, a separate patch release liner <NUM> may releasably cover the patch attachment device, and one or more separate dressing release liners <NUM> may cover the attachment device for the negative-pressure dressing <NUM>. In other embodiments, one or more release liner <NUM> may cover both the patch attachment device and the attachment device for the negative-pressure dressing <NUM> (e.g. the patch release liner may be integrated into the one or more release liners for the negative-pressure dressing <NUM>).

In some embodiments, the ventilation conduit <NUM> may comprise a proximal end configured to be fluidly coupled to the vent opening of the isolation patch <NUM>, and a distal end configured to be positioned external to the negative-pressure dressing <NUM>. In some embodiments, the proximal end of the ventilation conduit <NUM> may be in fluid communication with the patch manifold <NUM> through the patch cover <NUM>. In some embodiments, the ventilation conduit <NUM> may comprise a filter <NUM>, which may be positioned in-line (e.g. in the passage of the conduit, between the distal end and the proximal end) and/or configured to filter airflow from the ambient environment to the isolation patch <NUM>. In some embodiments, the filter <NUM> may comprise one or more of the following: a bacterial filter, a hydrophobic filter, and a charcoal filter. In some embodiments, the ventilation conduit <NUM> may be configured to resist collapse under negative-pressure therapy, for example being sufficiently rigid to resist full compression and/or to maintain an open pathway when in use. In some embodiments, the vent between the isolation patch <NUM> and the ambient environment may be sized sufficiently to maintain ambient pressure within the isolated zone during negative-pressure therapy. For example, the vent may be sized with a flow rate of about <NUM>/minute or greater than <NUM>/minute in some embodiments.

<FIG> is a schematic cross-section view of the dressing <NUM> of <FIG> in place on an exemplary tissue site <NUM>, illustrating additional details that may be associated with some embodiments. The isolation patch <NUM> may cover the portion of the tissue site <NUM> which is to be isolated (e.g. shielded from negative pressure and/or maintained at ambient pressure), forming a first sealed space <NUM> (which may form the isolated zone and/or zone of ambient pressure). The negative-pressure dressing <NUM> may cover the isolation patch <NUM> and the tissue site <NUM>, forming a second sealed space <NUM> (which may form the negative-pressure zone). For example, the negative-pressure dressing <NUM> may be coupled over the tissue site <NUM>, with the isolation patch <NUM> located thereunder. The isolation patch <NUM> may be located between the portion of the tissue site <NUM> and the negative-pressure dressing <NUM>, with the negative-pressure dressing <NUM> surrounding the isolation patch <NUM>. In some embodiments, the first sealed space <NUM> may be located within the second sealed space <NUM>, and the first sealed space <NUM> may be isolated from the second sealed space <NUM> (e.g. with substantially no fluid communication therebetween). In some embodiments, the manifold <NUM> for the negative-pressure dressing <NUM> may be located between the isolation patch <NUM> and the cover <NUM> for the negative-pressure dressing <NUM>. In some embodiments, a portion of the manifold <NUM> located over the isolation patch <NUM> may be compressed (e.g. to form a space within the negative-pressure dressing <NUM> for the isolation patch <NUM>), while other embodiments of the manifold <NUM> may comprise a cavity (not shown, but located to open on the inward-facing surface of the manifold) configured to receive the isolation patch <NUM>. In some embodiments, the isolation patch <NUM> may be attached to the negative-pressure dressing <NUM> (e.g. coupled to the manifold <NUM>), for example forming a unitary dressing assembly. In other embodiments, the isolation patch <NUM> may initially be separate from the negative-pressure dressing <NUM>, for example allowing placement of the isolation patch <NUM> first, before placement of the negative-pressure dressing <NUM>.

In some embodiments, the ventilation conduit <NUM> of the isolation patch <NUM> may extend out from under the negative-pressure dressing <NUM>, with the distal end of the ventilation conduit located external to the negative-pressure dressing <NUM>. For example, the ventilation conduit <NUM> may extend between the manifold <NUM> of the negative-pressure dressing <NUM> and the tissue site <NUM>, out beyond the perimeter of the negative-pressure dressing <NUM> where the cover <NUM> attaches to the tissue site <NUM>. The attachment device may seal the cover <NUM> of the negative-pressure dressing <NUM> around the ventilation conduit <NUM>, preventing any substantial leakage at the location where the ventilation conduit <NUM> exits from under the negative-pressure dressing <NUM> at the perimeter of the negative-pressure dressing <NUM>.

<FIG> is a schematic view illustrating an exemplary system having the dressing <NUM> of <FIG> in place on an exemplary tissue site, illustrating additional details that may be associated with some embodiments. As shown in <FIG>, the isolation patch <NUM> may underlie the negative-pressure dressing <NUM>, while the negative-pressure dressing <NUM> is on the tissue site. The negative-pressure dressing <NUM> may cover and seal the tissue site for negative-pressure therapy, and the isolation patch <NUM> may cover and seal the portion of the tissue site (to be shielded from negative pressure). The ventilation conduit <NUM> may extend out from the isolation patch <NUM>, beyond the negative-pressure dressing <NUM>, to provide fluid communication between the isolation patch <NUM> and the ambient environment. Fluid communication with the ambient environment may ensure that the isolation patch <NUM> maintains ambient pressure within the first sealed space. The negative-pressure source <NUM> may be fluidly coupled to the negative-pressure dressing <NUM>. For example, the fluid conductor <NUM> may fluidly couple the negative-pressure source <NUM> to the dressing interface <NUM> of the negative-pressure dressing <NUM>. The negative-pressure source <NUM> may be configured to provide negative pressure to the second sealed space of the negative-pressure dressing <NUM>, thereby providing negative-pressure therapy to the tissue site. The isolation patch <NUM> may shield the portion of the tissue site underlying the isolation patch <NUM> from negative pressure, for example with the first sealed space providing and/or maintaining ambient pressure to the portion of the tissue site (despite the application of negative-pressure in the second sealed space surrounding the isolation patch <NUM>). In some embodiments, the isolation patch <NUM> may also (e.g. simultaneously) shield the portion of the tissue site from appositional and/or decompressive forces which may be caused by the negative-pressure therapy within the negative-pressure dressing <NUM>.

In <FIG>, the isolation patch <NUM> may cover the nipple of the patient (e.g. the portion of the tissue site may comprise a nipple), and the negative-pressure dressing <NUM> may cover a breast of the patient (e.g. the tissue site may comprise the breast). Application of negative pressure from the negative-pressure source <NUM> may provide negative-pressure therapy to the breast tissue site through the negative-pressure dressing <NUM>, except for the nipple portion of the tissue site (which may experience ambient pressure and/or may not experience substantial appositional and/or decompressive forces under the isolation patch <NUM>).

While <FIG> illustrates the dressing on a breast tissue site, with the isolation patch over the nipple portion of the tissue site, other dressing embodiments may be configured for use on different tissue sites. For example, some dressing embodiments may have an isolation patch configured for use over a genital region. Some dressing embodiments may be configured for use with colorectal surgery. Some dressing embodiments may have an isolation patch configured to cover compromised vascular structures. A two-zone dressing may be useful anytime the tissue site generally may benefit from negative-pressure wound therapy, but also includes a portion of the tissue site that may not be suitable or recommended for negative-pressure wound therapy.

<FIG> is a schematic cross-section view of yet another example embodiment of a dressing <NUM> that may be associated with an example embodiment of the therapy system of <FIG>. The dressing <NUM> of <FIG> may be similar to that of <FIG>, but may be configured to vent the isolation patch <NUM> (e.g. the first sealed space <NUM>) through the cover <NUM> of the negative-pressure dressing <NUM>. For example, the ventilation conduit <NUM> may fluidly couple from the isolation patch <NUM> to the ambient environment through the cover <NUM> of the negative-pressure dressing <NUM>. In some embodiments, the cover <NUM> may comprise a ventilation port <NUM>, allowing the vent to penetrate the cover <NUM>, and the distal end of the ventilation conduit <NUM> may be fluidly coupled to the ambient environment outside the negative-pressure dressing <NUM> through the ventilation port <NUM>. In some embodiments, the ventilation conduit <NUM> may also penetrate the manifold <NUM> of the negative-pressure dressing <NUM>. In other embodiments, the ventilation conduit <NUM> may not penetrate the manifold <NUM>, but rather may extend around the manifold <NUM> of the negative-pressure dressing <NUM> (e.g. between the manifold and the cover) to fluidly couple the isolation patch <NUM> to the ventilation port <NUM>. In some embodiments, the ventilation port <NUM> may be configured to substantially prevent leakage between the ambient environment and the second sealed space <NUM> within the negative-pressure dressing <NUM>.

<FIG> is an exploded, isometric view of still another example embodiment of a dressing <NUM> (or dressing assembly) that may be associated with an example embodiment of the therapy system of <FIG>. Dressing <NUM> of <FIG> may be similar to that of <FIG>, but the isolation patch <NUM> may be configured to be un-vented (e.g. completely sealed, so as to be sealed to both the negative pressure of the negative-pressure dressing <NUM> and the ambient environment), without any fluid communication between the isolation patch <NUM> and the ambient environment. For example, the isolation patch <NUM> may be configured to seal the portion of the tissue site to block negative pressure and/or to retain ambient pressure, and/or configured to resist or dampen appositional and decompression forces, without having a vent to ambient atmosphere. Thus, the isolation patch <NUM> of <FIG> may have no vent. In some embodiments, the negative-pressure dressing <NUM> of <FIG> may be similar to or identical with that of <FIG>.

<FIG> is a schematic cross-section view of the isolation patch <NUM> portion of the dressing of <FIG>, illustrating additional details that may be associated with some embodiments. The isolation patch <NUM> of <FIG> may be configured to be unvented (e.g. not vented to the ambient environment). In some embodiments, the isolation patch <NUM> may comprise or consist essentially of a force-dissipating pad. In <FIG>, the isolation patch <NUM> may comprise a force-dissipating pad and a patch cover <NUM> disposed over the force-dissipating layer to form the outer surface of the isolation patch <NUM>. In some embodiments, the patch cover <NUM> may be configured to prevent fluid flow therethrough, and may be unvented (e.g. with no openings therethrough). In some embodiments, the patch cover <NUM> may be occlusive. In some embodiments, the force-dissipating pad may comprise a gel layer <NUM>, which may be configured to resist appositional and/or decompressive forces arising due to negative-pressure therapy. In some embodiments, the force-dissipating pad, such as gel layer <NUM>, may be occlusive. For example, the force-dissipating pad may substantially resist airflow so as to be substantially non-existent. In some embodiments, the force-dissipating pad may have low surface roughness, a thickness greater than <NUM>/<NUM> inch, and/or a low durometer (such as <NUM> or softer on the SHORE <NUM> scale). In some embodiments, the gel layer <NUM> may comprise TPE gel and/or have a thickness of about <NUM> - <NUM>. In some embodiments, the force-dissipating pad may comprise one or more other dense materials that are occlusive and/or that resist appositional and/or decompressive forces (e.g. with characteristics similar to the gel layer). For example, the force-dissipating pad may comprise one or more of the following: silicone, rubber with a low durometer, and closed-cell foam. In some embodiments, the isolation patch <NUM> may further comprise an attachment device (not shown), configured to attach the isolation patch <NUM> to the portion of the tissue site and to form a seal around the perimeter (e.g. so that the first sealed space/isolated zone/zone of ambient pressure within the isolation patch <NUM> is completely sealed around the portion of the tissue site and does not allow fluid communication with either the second sealed space/negative-pressure zone or the ambient environment outside the negative-pressure dressing <NUM>). In some embodiments, the gel layer <NUM> may be adhesive and/or may function as an integral attachment device, such that a separate attachment device may not be necessary. In some embodiments, the gel layer <NUM> may be sufficiently occlusive and/or nonporous to effectively seal the portion of the tissue site against negative pressure and/or to maintain the portion of the tissue site at ambient pressure, and no separate patch cover may be required. For example, such exemplary isolation patch <NUM> embodiments may consist essentially of the gel layer <NUM> (or other force-dissipating pad) adhered to the portion of the tissue site (and/or may include the attachment device configured to attach the gel layer to the portion of the tissue site, in some embodiments).

In some embodiments, the isolation patch <NUM> may be configured to block negative pressure (e.g. shield the portion of the tissue site from negative pressure). For example, the seal provided by the isolation patch <NUM> may be sufficient to prevent migration of negative pressure from the surrounding negative-pressure dressing <NUM> into the isolation patch <NUM>. In some embodiments, the isolation patch <NUM> may be configured to maintain or provide a pressure different than that of the negative-pressure dressing <NUM>, for example approximately ambient atmospheric pressure, a positive pressure, or a negative pressure that is substantially less (e.g. closer to <NUM> mmHg) than that within the negative-pressure dressing.

<FIG> is a schematic cross-section view of the dressing <NUM> of <FIG> in place on an exemplary tissue site, illustrating additional details that may be associated with some embodiments. The dressing <NUM> embodiment of <FIG> may be similar to that of <FIG>, except that the isolation patch <NUM> may be similar to that of <FIG> (e.g. unvented). Thus, in <FIG>, there may be no vent or ventilation conduit, and the cover <NUM> of the negative-pressure dressing <NUM> may seal entirely around the perimeter of the negative-pressure dressing <NUM> (e.g. without any opening or anything passing out of the second sealed space <NUM> to the ambient environment). The isolation patch <NUM> may completely seal the portion of the tissue site (e.g. to prevent any fluid communication in or out of the first sealed space <NUM>), and the negative-pressure dressing <NUM> may cover the isolation patch <NUM> and the tissue site (e.g. with the isolation patch <NUM> located within and surrounded by the second sealed space <NUM> of the negative-pressure dressing <NUM>).

Methods, for providing negative pressure wound therapy to a tissue site, are also disclosed herein. For example, some method embodiments may comprise: fluidly isolating a portion of the tissue site from negative pressure; sealing the tissue site for negative-pressure wound therapy; and applying negative pressure to the tissue site, except at the isolated portion of the tissue site. In some embodiments, fluidly isolating a portion of the tissue site may comprise applying an isolation patch over/covering the portion of the tissue site; and sealing the tissue site may comprise applying a negative-pressure dressing over/covering the isolation patch and the tissue site. In some embodiments, applying an isolation patch may comprise sealing the isolation patch over the portion of the tissue site to form a first sealed space with ambient pressure; and applying a negative-pressure dressing may comprise sealing the negative-pressure dressing over the isolation patch and the tissue site, to form a second sealed space configured for negative-pressure therapy. Some embodiments may further comprise fluidly coupling the isolation patch to an ambient environment. For example, fluidly isolating a portion of the tissue site from negative pressure may further comprise fluidly coupling the first sealed space of the isolation patch to the ambient environment. Some embodiments may further comprise fluidly coupling the negative-pressure dressing to a negative-pressure source, so that negative pressure may be applied through the negative-pressure dressing to the tissue site, except for the portion of the tissue site isolated by the isolation patch.

In some embodiments, fluidly coupling the isolation patch to the ambient environment may comprise fluidly coupling a proximal end of a ventilation conduit to a patch manifold of the isolation patch through a patch cover for the isolation patch, and positioning a distal end of the ventilation conduit outside a cover for the negative-pressure dressing. In some embodiments, the ventilation conduit may not penetrate the cover for the negative-pressure dressing. For example, the ventilation conduit may pass between the cover for the negative-pressure dressing and the tissue site and/or may be sealed as it exits the negative-pressure dressing by an attachment device for the negative-pressure dressing (which may be located between the cover for the negative-pressure dressing and the tissue site). In some embodiments, fluidly coupling the isolation patch to the ambient environment may comprise fluidly coupling the isolation patch to a ventilation port in a cover for the negative-pressure dressing (e.g. so that the vent penetrates the cover for the negative-pressure dressing). In some embodiments, the isolation patch may comprise a gel layer, and fluidly isolating a portion of the tissue site from negative pressure may further comprise preventing substantially any fluid communication between the first sealed space and the second sealed space. In some embodiments, fluidly isolating the portion of the tissue site may also further comprise fluidly isolating the isolation patch (e.g. the first sealed space) from the ambient environment. For example, fluidly isolating the portion of the tissue site may comprise fluidly isolating the isolation patch (e.g. first sealed space) so that there is substantially no fluid communication in or out of the isolation patch. Some embodiments may further comprise resisting or reducing appositional and/or decompressive forces arising due to negative-pressure therapy. For example, the isolation patch may comprise a force-dissipating pad, such that applying the isolation patch may protect the portion of the tissue site from such forces. In some embodiments, the portion of the tissue site may comprise a nipple of a patient, and applying the isolation patch may comprise applying the isolation patch over the nipple. In some embodiments, the tissue site may comprise a breast of the patient, and applying the negative-pressure dressing may comprise applying the negative-pressure dressing over the breast. In some embodiments, the isolation patch may be applied to the portion of the tissue site before application of the negative-pressure dressing to the tissue site. In some embodiments, the isolation patch may be applied to the portion of the tissue site before application of negative pressure to the negative-pressure dressing. In some method embodiments, the dressing or dressing assembly may be similar to those two-part devices described herein.

Claim 1:
A system comprising:
a negative-pressure dressing (<NUM>) configured for application of negative pressure to a tissue site;
an isolation patch (<NUM>), configured for use under the negative-pressure dressing (<NUM>) and configured to fluidly isolate a portion of the tissue site from the negative pressure; and
a negative-pressure source (<NUM>) fluidly coupled to the negative-pressure dressing (<NUM>).