Patent Description:
During the treatment of a wound, the wound and surrounding skin (periwound) may be isolated from the ambient environment by a wound dressing to stimulate quicker healing. The wound dressing is typically defined by a fluid absorbency capacity that remains unchanged over time. Thus, once the fluid capacity of the wound dressing has been reached, the wound dressing will be incapable of absorbing or holding any additional fluid. In such situations, the exposure of the wound dressing to any additional fluid may put the wound dressing at a risk of leaking, swelling, and becoming detached.

Additionally, excess moisture within the wound dressing may decrease the effectiveness of wound treatment and lead to patient discomfort. In particular, excess moisture within a wound dressing may act as a thermal insulator, which induces sweating and patient discomfort. Moreover, sustained exposure to moisture increases the risk of tissue maceration-particularly when the wound dressing is applied over large areas of peri wound. To avoid the problems associated with excess moisture, users are often required to increase the frequency with which wound dressings are changed during the treatment of the wound. Wound treatment systems for managing moisture during the treatment of a wound are known for example from <CIT>.

It would therefore be desirable to provide a wound treatment system configured to accelerate the evaporation of fluid from a wound dressing.

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

Insofar as the term example or embodiment is used in the following, or features are presented as being optional, this should be interpreted in such a way that the only protection sought is that of the invention claimed. Reference(s) to "embodiment(s)" or "example(s)" throughout the description which are not under the scope of the appended claims merely represent possible exemplary executions and are not part of the present invention.

Referring to the FIGURES, a wound treatment system configured to facilitate the removal of excess moisture from a wound site is shown according to various exemplary embodiments. As illustrated in <FIG> and <FIG>, the wound treatment system <NUM> generally includes a wound dressing <NUM> configured to be positioned around a wound (e.g. covering the wound), and a moisture management system <NUM> configured to increase the rate at which moisture is removed from a treatment space defined underneath the wound dressing <NUM>.

Referring to <FIG>, and <FIG>, the moisture management system <NUM> is configured to increase the rate at which moisture is removed from the wound dressing <NUM> by generating and directing a forced flow of dry air along an upper surface <NUM> of a liquid permeable drape layer <NUM> of the wound dressing <NUM>. As the forced, dry air flows across the drape layer <NUM>, moles of moisture which have permeated the drape layer <NUM> and pooled on an upper surface <NUM> thereof are lifted and removed by the dry air from the upper surface <NUM> of the drape layer <NUM>. This removal of pooled moisture from the drape layer <NUM> allows additional moisture located within the treatment space to permeate through the liquid permeable drape layer <NUM>. This accelerated diffusion and evaporation of liquid through the drape layer <NUM> resulting from the directed flow of dry air along the drape layer <NUM> generated by the moisture management system <NUM> increases the total fluid handling capacity of the wound dressing <NUM>. Thus, the wound treatment system <NUM> actively extends the life of the static capacity of the wound dressing <NUM>, which in turn prolongs the wear time of the wound dressing <NUM> without the need for an external reservoir to collect fluids removed from the treatment space. By reducing the frequency with which a wound dressing <NUM> needs to be changed, and by obviating the need for a patient to be tethered to an external fluid collection reservoir, the wound treatment system <NUM> advantageously minimizes the inconveniences to a user during the treatment of the wound. The ability of the wound treatment system <NUM> to accelerate the evaporation of fluid from within a wound dressing <NUM> may also advantageously further be used to minimize, or eliminate, patient discomfort typically associated with excess moisture at a wound site (such as, e.g., the increased risk of periwound maceration, increased sweating, etc.).

The wound dressing <NUM> may be defined by a variety of different types of wound dressings. The wound dressing <NUM> may also be configured to treat a variety of different types of wounds, and for use in a variety of different types of wound treatments. The wound dressing <NUM> may be used as a stand-alone wound treatment, or may be a component of an additional wound therapy system with which the wound treatment system <NUM> is used, such as, e.g., a negative pressure wound treatment ("NPWT") system, an instillation therapy system, etc..

The wound dressing <NUM> includes a drape layer <NUM>, and optionally any number and combination of additional layers. The number and selection of the additional dressing layers forming the wound dressing <NUM> may vary depending on a variety of factors, including, but not limited to: the type of wound being treated, the location of the wound being treated, the type of treatment being provided to the wound, the type of optional additional wound therapy system with which the wound treatment system <NUM> is used, etc. Non-limiting examples of additional dressing layers which may form a part of the wound dressing <NUM> include, e.g., an absorbent layer <NUM>, an interface layer <NUM>, a manifold layer <NUM>, a wicking layer, etc..

The drape layer <NUM> of the wound dressing <NUM> supports the additional layers of the wound dressing <NUM> (e.g., the absorbent layer <NUM>, the interface layer <NUM>, the manifold layer <NUM>, etc.) at the wound site. As described in more detail below, an upper surface <NUM> of the drape layer <NUM> delimits a lower portion of the flow path <NUM> of the wound treatment system <NUM>.

As shown in <FIG> and <FIG>, in some embodiments, a perimeter of the drape layer <NUM> extends beyond (e.g., circumscribes) a perimeter of the absorbent layer <NUM> (e.g., such as shown in <FIG>), a perimeter of the manifold layer <NUM> (e.g., as shown in <FIG>) and/or the perimeter of any other additional dressing layer(s) to provide an adhesive-coated margin for adhering the additional layers of the wound dressing <NUM> to the skin of a patient adjacent to the wound site being treated. In other embodiments, the adhesive-coated margin can be eliminated and wound dressing <NUM> can be adhered to the skin of a patient using other techniques.

The drape layer <NUM> may be formed from any number of different types of materials that are substantially impermeable to liquid and substantially permeable to moisture vapor. In other words, the drape layer <NUM> is permeable to water vapor, but not permeable to liquid water or wound exudate. This increases the total fluid handling capacity of the wound dressing <NUM> while promoting a moist wound environment. In some embodiments, the drape layer <NUM> is also impermeable to bacteria and other microorganisms. A suitable material for the drape layer <NUM> is a high moisture vapor transmission rate ("MVTR") material. As described in detail below, the wound treatment system <NUM> exploits the high MVTR of the drape layer <NUM> to manage fluids within the wound dressing <NUM>. In some embodiments, the drape layer <NUM> is a thin layer of polyurethane film. One example of a suitable material for the drape layer <NUM> is the polyurethane film known as ESTANE 5714F. Other suitable polymers for forming the drape layer <NUM> include poly alkoxyalkyl acrylates and methacrylates, such as those described in Great <CIT>, the entire disclosure of which is incorporated by reference herein.

As illustrated by the wound treatment system <NUM> embodiment of <FIG> and <FIG>, the wound dressing <NUM> according to some embodiments is an absorbent wound dressing comprising an absorbent layer <NUM> that is adapted to collect (e.g. store) fluid from the wound site. The size and shape of the absorbent layer <NUM> may be varied as desired. As illustrated in <FIG> and <FIG>, in some embodiments the absorbent layer <NUM> comprises superabsorbent particles held within a liquid-tight envelope (e.g. a woven or non-woven pouch). Other non-limiting examples of absorbent layer <NUM> materials include superabsorbent fibers, superabsorbent polymers, hydrofibers, sodium carboxymethyl cellulose, alginates, sodium polyacrylate, hydrogels, hydrocolloids, etc..

As illustrated by the wound treatment system <NUM> embodiment of <FIG>, the wound dressing <NUM> in various embodiments includes a manifold layer <NUM> configured to allow fluid (e.g. exudates, liquids, a vacuum created by the operation of the pump of the NPWT system) to be transmitted (e.g. distributed) to/from the wound. When treating highly exuding wounds, the manifold layer <NUM> may optionally include an open-cell foam marketed as GRANUFOAM™ by ACELITY™. In other embodiments, it may be advantageous to retain some degree of fluid in the wound dressing <NUM> such that the wound does not entirely dry out (which may be harmful for healing). Accordingly, in such embodiments the manifold layer <NUM> may instead include a foam that is more hydrophilic than standard GRANUFOAM™. In such embodiments, the ability of the manifold layer <NUM> to retain fluid may additionally assist in the fluid management of the wound dressing <NUM>, with exudates and other fluids absorbed by the manifold layer <NUM> being evaporated by the forced airflow through the flow path <NUM> generated during operation of the air displacement device <NUM>. Non-limiting examples of additional materials from which the manifold layer <NUM> may be formed include cellular foam, un-reticulated open-cell foam, porous tissue collections, gauze, felted mat, and/or any other material comprising a plurality of flow channels or pathways via which fluids may be distributed.

In various embodiments, the interface layer <NUM> is configured to reduce potential adherence of the wound dressing <NUM> to the wound and/or to prevent ingrowth of skin to the wound dressing <NUM>. The interface layer <NUM> may be defined by a nonporous material comprising a plurality of perforations (fenestrations, holes, airways, windows, slits, etc.) extending therethrough that allow air and fluid to pass between the wound and the other layers of the wound dressing <NUM>. In some embodiments, the interface layer <NUM> is made of a hydrophobic material such as polyethylene (PE) or other hydrophobic polymers.

According to some embodiments, the interface layer <NUM> may comprise a liquid-impermeable, elastomeric film having a plurality of bi-directional, pressure-responsive perforations formed therethrough. The interface layer <NUM> is optionally dimensioned such that an outer perimeter of the interface layer <NUM> is coextensive with, or slightly greater than the manifold layer <NUM> and/or absorbent layer <NUM> (e.g., the area of the interface layer <NUM> is between approximately <NUM>% and <NUM>% greater than the area of the manifold layer <NUM> and/or absorbent layer <NUM>). The fluid restrictions define elastic passages that can expand (e.g. open) in response to a pressure gradient to allow flow therethrough. In the absence of a pressure gradient, the passages may be sufficiently small to form a seal or fluid restriction, thereby reducing or preventing liquid flow through the interface layer <NUM>. Non-limiting examples of various materials from which the film defining the interface layer <NUM> in such embodiments may be formed include polyurethane, polyethylene, acrylics, polyolefin (such as cyclic olefin copolymers), polyacetates, polyamides, polyesters, copolyesters, PEBAX block copolymers, thermoplastic elastomers, thermoplastic vulcanizates, polyethers, polyvinyl alcohols, polypropylene, polymethylpentene, polycarbonate, styreneics, silicones, fluoropolymers, acetates, etc. In some such embodiments, the film may have thickness between approximately <NUM> microns and approximately <NUM> microns, and more specifically between approximately <NUM> microns and approximately <NUM> microns.

In some embodiments, the perforations comprise linear slots having a length less than approximately <NUM> millimeters (e.g. <NUM> millimeters), with adjacent slots spaced approximately <NUM> millimeters from one another. In other embodiments, the perforations may be defined by other configurations (e.g. holes) that are arranged in generally linear clusters having a length less than approximately <NUM> millimeters or less (e.g. <NUM> millimeters), with adjacent clusters optionally spaced approximately <NUM> millimeters from one another. In yet other embodiments, the perforations may be defined by any other variety of arrangements and dimensions.

The moisture management system <NUM> operates to control moisture levels in a treatment space defined underneath the wound dressing <NUM> of the wound treatment system <NUM> by forcing airflow along an upper, outer surface of the wound dressing <NUM>. Although the management of moisture levels in the treatment space may, in some embodiments, optionally be supplemented via the direct removal of fluids from the treatment space using a source of forced negative airflow (e.g. a pump) fluidly coupled to the treatment space-the management of moisture levels using the moisture management system <NUM> of the wound treatment system <NUM> described herein does not itself require fluid communication with the treatment space beneath the wound dressing <NUM>. Rather, the forced airflow along the wound dressing <NUM> generated during operation of the moisture management system <NUM> indirectly removes moisture from the treatment space (i.e. removes moisture from the treatment space even in the absence of any fluid communication with the treatment space) by accelerating the diffusion and evaporation of fluid within the treatment space through the high MVTR drape layer <NUM> of the wound dressing <NUM>.

As shown in <FIG> and <FIG>, the moisture management system <NUM> generally includes a film layer <NUM>, a spacer structure <NUM>, and an air displacement device <NUM>. The film layer <NUM> and spacer structure <NUM> are configured to be coupled (e.g. attached, supported by, adhered, etc.) to the wound dressing <NUM> to define a flow path <NUM> that extends along an upper (e.g., exterior, outer, etc.) surface of the wound dressing <NUM> (i.e., along the upper surface <NUM> of the drape layer <NUM>). The air displacement device <NUM> is configured to be fluidly coupled to the flow path <NUM>, with operation of the air displacement device <NUM> being used to generate air flow across the upper surface <NUM> of the drape layer <NUM> of the wound dressing <NUM>.

Some or all of the components of the moisture management system <NUM> may be single use, or may optionally be configured to be re-used with different wound dressings <NUM>. In some embodiments, the moisture management system <NUM> is configured for stand-alone treatment of a wound (i.e., wherein the wound treatment system <NUM> operates independent of any other wound therapy system or device). In other embodiments, the moisture management system <NUM> may be configured for use alongside other wound therapy systems, such as, e.g., an NPWT system.

Referring to <FIG>, upon assembly of the wound treatment system <NUM>, the film layer <NUM> (e.g. support layer) of the moisture management system <NUM> delimits an upper portion of a flow path <NUM> that extends along the upper surface <NUM> of the drape layer <NUM>. As shown in <FIG>, an opening <NUM> extending through the film layer <NUM> fluidly couples the flow path <NUM> to the air displacement device <NUM>. When the wound treatment system <NUM> is operated in a positive pressure mode (described below), the opening <NUM> defines an inlet via which airflow generated by the air displacement device <NUM> enters the flow path <NUM>. During operation of the wound treatment system <NUM> in a negative pressure mode (described below), the opening <NUM> defines an outlet via which air is evacuated from the flow path <NUM> by the air displacement device <NUM>. As discussed below, the film layer <NUM> optionally also includes and/or defines a plurality of vents <NUM> via which air flows into or out from the flow path <NUM> during operation of the air displacement device <NUM>.

The film layer <NUM> optionally supports a connector <NUM> (e.g., a port, a SENSAT. ™ connection pad marketed by ACELITY™, etc.) via which the air displacement device <NUM> is coupled to the flow path <NUM>. The connector <NUM> may indirectly couple the air displacement device <NUM> to the flow path <NUM> via a conduit <NUM> that is attached to and extends between the connector <NUM> and a remotely located air displacement device <NUM>. Alternatively, in some embodiments, the air displacement device <NUM> and the connector <NUM> are components of an integrated module <NUM> (described in more detail below) that is supported relative to the film layer <NUM> (see, e.g., <FIG>) around (e.g. adjacent to, surrounding, etc.) an outer periphery of the opening <NUM> in the film layer <NUM>, such that the wound treatment system <NUM> defines a single, unitary structure.

In some embodiments, the opening <NUM> extends through a substantially central location of the film layer <NUM>, so as to facilitate a generally uniform distribution of air flow along the upper surface of the wound dressing <NUM>. In other embodiments, the fluid opening <NUM> (and corresponding connection between the air displacement device <NUM> and the flow path <NUM>) may be arranged at other locations relative to the film layer <NUM> and/or wound dressing <NUM>. For example, when treating a wound that exudes fluids at varying rates at different locations, the opening <NUM> is optionally formed at a location along the film layer <NUM> that will overlie a region of the wound that exudes fluid at a high rate. As another example, in embodiments in which the wound dressing <NUM> is attached at a location on a patient where gravity will result in the pooling of exudate at a lower portion of the wound dressing <NUM> (e.g. when the wound dressing <NUM> is attached to a leg, torso, upper arm, etc.), the fluid opening <NUM> may be formed at a location adjacent to a lower perimeter of the film layer <NUM>.

The dimensions of the film layer <NUM> may be smaller, the same as, or larger than the dimensions of the wound dressing <NUM> of the wound treatment system <NUM>. The dimensions of the film layer <NUM> relative to the wound dressing <NUM> may be selected based on an intended treatment protocol. For example, given the detrimental effect moisture may have on a periwound, in various embodiments the film layer <NUM> is sized to be coextensive with, or extend beyond, the outer perimeter of the wound dressing <NUM> to which the moisture management system <NUM> is attached, such as, e.g., representatively illustrated in <FIG>. Such an arrangement advantageously allows the flow path <NUM> to be defined across the entirety of the upper surface <NUM> of the drape layer <NUM>-including those portions of the drape layer <NUM> that overlay the periwound. In other embodiments, the film layer <NUM> is dimensioned smaller than the wound dressing <NUM>, such that a flow path <NUM> is defined along only a designated portion of the upper surface <NUM> of the drape layer <NUM>. Such a configuration may be advantageous in situations in which it is desired to reduce levels of moisture at a specific location along a wound without significantly effecting moisture levels at other locations along the wound (such as, e.g. may occur during the treatment of larger wounds) and/or to minimize unnecessary power consumption resulting from the operation of the air displacement device <NUM> to cause air flow across a greater area than needed.

In some embodiments, the film layer <NUM> is attached to an underlying surface (e.g. an upper surface of the wound dressing <NUM>, the skin of a patient, etc.) in situ during the attachment of the wound treatment system <NUM> to the patient. In such embodiments, adhesive is optionally provided along portions, or the entirety, of the perimeter of the lower surface <NUM> of the film layer <NUM> to facilitate the attachment of the film layer <NUM> to the underlying surface. Alternatively, the film layer <NUM>, spacer structure <NUM> and drape layer <NUM> are optionally provided as a single, integrated assembly, in which the perimeter of the film layer <NUM> is preattached (via, e.g., adhesive, welding, etc.) to the drape layer <NUM>.

As noted above, the film layer <NUM> includes and/or defines one or more vents <NUM> via which air is forced out from or into the flow path <NUM> during operation of the air displacement device <NUM>. In some embodiments, such as, e.g., shown in <FIG> and <FIG>, the vents <NUM> include openings <NUM> (e.g. apertures, etc.) that extend through the film layer <NUM>.

As shown in <FIG>, the vents <NUM> may also optionally be defined by unattached portions <NUM> of a perimeter of the film layer <NUM> that are not directly coupled to an underlying surface (e.g. the wound dressing <NUM>, the skin of a patient, etc.). As illustrated by <FIG>, <FIG> and <FIG>, in some such embodiments the flow elements <NUM> of the spacer structure <NUM> (described below) that are located around (e.g. adjacent to, surrounding, etc.) the perimeter of the film layer <NUM> are formed having a greater height (e.g., the flow elements <NUM> extend further downward relative to an upper surface <NUM> of the film layer <NUM>) than flow elements <NUM> that are located along an interior portion of the lower surface <NUM> of the film layer <NUM>. Such an increased height of the flow elements <NUM> located around the outer perimeter of the film layer <NUM> is configured to ensure that the unattached portions <NUM> of the outer periphery of the film layer <NUM> remain offset from the underlying surface to which the film layer <NUM> is attached (e.g. the wound dressing <NUM>, the skin of the patient, etc.) and do not occlude flow into/out from the flow path <NUM>.

In embodiments in which the wound treatment system <NUM> is configured to be operated in a negative pressure mode, valves and/or filters are optionally located within some or all of the vents <NUM>. During operation of the wound treatment system <NUM> in the negative pressure mode, the optional valves (e.g., slit valves <NUM>) are configured to provide control over the rate of ambient air flow into the flow path <NUM>, while the optional filters are configured to prevent microorganisms or other harmful particles from entering the flow path <NUM> (and air displacement device <NUM>).

The spacer structure <NUM> (e.g. spacer assembly, support structure) of the moisture management system <NUM> vertically offsets (e.g., spaces apart, separates, elevates, etc.) the lower surface <NUM> of the film layer <NUM> from the upper surface <NUM> of the drape layer <NUM> upon assembly of the wound treatment system <NUM>. The space (e.g., void, air gap, etc.) defined between the lower surface <NUM> of the film layer <NUM> and the upper surface <NUM> of the drape layer <NUM> as a result of this vertical offset defines a portion of the flow path <NUM> of the wound treatment system <NUM>.

The spacer structure <NUM> includes one or more flow elements <NUM> each having an outer surface that extends between a first end <NUM> (e.g., an upper end) and a second end <NUM> (e.g., a lower end). Upon assembly of the wound treatment system <NUM>, the spacer structure <NUM> is arranged relative to the wound dressing <NUM> and film layer <NUM> so that the first ends <NUM> of the flow elements <NUM> are located adjacent and extend downwards relative to the lower surface <NUM> of the film layer <NUM>. The second ends <NUM> of the flow elements <NUM> are located adjacent to and extend upwards relative to the upper surface <NUM> of the drape layer <NUM>.

To facilitate assembly of the wound treatment system <NUM>, the second ends <NUM> of the flow elements <NUM> are optionally coated with an adhesive via which the spacer structure <NUM> can be attached relative to the upper surface <NUM> of the drape layer <NUM>. In embodiments in which the spacer structure <NUM> and film layer <NUM> are not monolithically, or otherwise integrally formed, the upper ends <NUM> of the spacer structure <NUM> may also optionally be coated with an adhesive via which the spacer structure <NUM> can be attached relative to the lower surface <NUM> of the film layer <NUM>. In yet other embodiments, the drape layer <NUM>, spacer structure <NUM> and film layer <NUM> are provided a single, integrated structure, such that assembly of the wound treatment system <NUM> in situ requires no more effort than would typically be required to assemble a wound dressing comprising a separately attachable backing layer (e.g. a drape layer).

As illustrated by the embodiments of <FIG>, the flow elements <NUM> may be defined by a variety of different structures having any number of different shapes, sizes and configurations. According to various embodiments, the flow element(s) <NUM> of the spacer structure <NUM> are provided as separate and discrete structure(s) from the film layer <NUM>, and are arranged relative to the film layer <NUM> and wound dressing <NUM> during assembly of the wound treatment system <NUM>.

To facilitate the assembly of the wound treatment system <NUM>, in other embodiments the spacer structure <NUM> and film layer <NUM> are optionally provided as a single, integral one-piece structure. In some such embodiments, the spacer structure <NUM> is monolithically formed with the film layer <NUM>, with the flow elements <NUM> including structures that are defined by the lower surface <NUM> of the film layer <NUM>. In other such embodiments, the flow elements <NUM> defining the spacer structure <NUM> include discrete structures that are attached to the lower surface <NUM> of the film layer <NUM>.

Illustrated in <FIG> are exemplary embodiments of integral, one-piece film layer <NUM> and spacer structure <NUM> assemblies. As shown in <FIG>, the flow elements <NUM> in some such embodiments include adhesive dots <NUM> (e.g. beads, islands, patches, etc.) formed from a cured semi-permanent or permanent adhesive (e.g., viscose UV curing adhesive). The adhesive dots <NUM> define discrete structures that are adhered at their respective first ends <NUM> to locations along the lower surface <NUM> of the film layer <NUM>. Upon assembly of the wound treatment system <NUM>, the second ends <NUM> of the adhesive dots <NUM> adhere the film layer <NUM> relative to the upper surface <NUM> of the drape layer <NUM>. The adhesive dots <NUM> are formed having a thickness (i.e. height), such that the first ends <NUM> are laterally offset from the second ends <NUM> by a distance that allows the adhesive dots <NUM> to support the film layer <NUM> in a spaced and separated arrangement relative to the wound dressing <NUM> upon assembly of the wound treatment system <NUM>. Although the adhesive dots <NUM> are shown as being provided pre-adhered to the film layer <NUM> to define an integral spacer structure <NUM>/film layer <NUM> assembly, an adhesive composition may alternatively be applied to the lower surface <NUM> of the film layer <NUM> (and/or to the upper surface <NUM> of the drape layer <NUM>) to form the adhesive dots <NUM> along the lower surface <NUM> of the film layer <NUM> and/or along the upper surface <NUM> of the drape layer <NUM> during assembly of the wound treatment system <NUM>.

As illustrated by the embodiment of <FIG>, instead of adhesive dots <NUM>, the discrete and separate flow elements <NUM> that define a single, unitary spacer structure <NUM> and film layer <NUM> assembly may instead include one or more flow walls <NUM> that are attached (e.g. adhered) to the lower surface <NUM> of the film layer <NUM>. Notably, in such embodiments, the flow wall(s) <NUM> can be defined by a variety of different shapes, sizes, and configurations.

Exemplary embodiments of spacer structures <NUM> that are monolithically formed with the film layer <NUM> are shown in <FIG>. As shown in <FIG>, in some such embodiments, the lower surface <NUM> of the film layer <NUM> is textured, and includes a plurality of peaks <NUM> that are separated from one another by valleys <NUM>. The flow elements <NUM> correspond to the peaks <NUM> of the textured surface, and are defined by portions of the lower surface <NUM> of the film layer <NUM> that extend further downward from an upper surface <NUM> of the film layer <NUM> (i.e. have an increased thickness) as compared to the portions of the lower surface <NUM> of the film layer <NUM> defining the valleys <NUM>. Although the peaks <NUM> defining the flow elements <NUM> are shown as being truncated pyramids, the peaks <NUM> may be formed into a variety of other different shapes (e.g. ridges, ribs, posts, etc.).

Turning to <FIG>, in other embodiments, a lower surface <NUM> of the film layer <NUM> is embossed to define a plurality of raised portions <NUM> (i.e. non-embossed portions of the film layer <NUM>). In such embodiments of a spacer structure <NUM> formed monolithically with the film layer <NUM>, the flow elements <NUM> are defined by the raised portions <NUM> of the lower surface <NUM>. Alternatively (or additionally), the upper surface <NUM> of the film layer <NUM> may be debossed, and the flow elements <NUM> are defined by the downwardly projecting, debossed portions of the upper surface <NUM> of the film layer <NUM> (not shown).

According to some embodiments, instead of the spacer structure <NUM> and film layer <NUM> being provided as an integral, one-piece assembly, the spacer structure <NUM> and drape layer <NUM> may alternatively be provided as an integral, one-piece assembly.

Shown in <FIG> and <FIG> are exemplary embodiments of spacer structures <NUM> that are provided separately and discretely from the film layer <NUM>, and which are arranged and optionally attached relative to the film layer <NUM> during assembly of the wound treatment system <NUM>. As shown in <FIG>, in some such embodiments the flow elements <NUM> include a plurality of struts <NUM> (e.g. walls) that are interconnected to form a scaffold which defines the spacer structure <NUM>.

Referring to <FIG>, in other embodiments, the discretely and separately provided spacer structure <NUM> is defined by a porous layer <NUM>. The porous layer <NUM> may be formed of a variety of different porous materials. For example, the porous layer <NUM> optionally includes a felted foam (having, e.g., a thickness of between approximately <NUM> and <NUM>), or a non-felted foam (having, e.g., a thickness of less than approximately <NUM>). In such embodiments, the porous material from which the porous layer <NUM> is formed defines the flow element <NUM> of the spacer structure <NUM>. According to some embodiments, the porous material (e.g. felted or non-felted foam) used to form the porous layer <NUM> that defines the space structure <NUM> of <FIG> may also be used to form the flow elements <NUM> of other spacer structure <NUM> embodiments, such as, e.g., flow walls <NUM> (see, e.g., <FIG>), struts <NUM> (see, e.g., <FIG>), etc..

As also illustrated by <FIG>, the shape, size, and arrangement of flow elements <NUM> of the spacer structure <NUM> may be varied as desired, such as, e.g., to define a flow path <NUM> that directs air in a manner along specific portions of the upper surface of the wound dressing <NUM>. For example, in embodiments in which it is desired to manage moisture across the entirety of the wound dressing <NUM>, the flow elements <NUM> may be arranged such that flow channels defined between adjacent flow elements <NUM> are fluidly interconnected and define a single flow path <NUM> that extends across the entirety of the portion of the upper surface <NUM> of the drape layer <NUM> (e.g., as representatively illustrated by the arrangement of flow elements <NUM> in <FIG>, <FIG> <FIG> and <FIG>).

Alternatively, it may instead be desired to direct dry air along only specific target locations along the wound dressing <NUM>, such as, e.g., to portions of the flow path <NUM> that overlie the periwound, or which overlie highly exuding regions of the wound. Accordingly, in some embodiments, the shape, size, and arrangement of flow elements <NUM> may be selected to define one or more enclosed flow channels that are discrete and fluidly isolated from other portions of the flow path <NUM> (such as, e.g., representatively illustrated by the embodiments of <FIG> and <FIG>).

In yet other embodiments, the arrangement of flow elements <NUM> in a non-uniform distribution, and/or the selection of flow elements <NUM> having varying sizes may be used to accelerate the rate of moisture removal at the target locations. For example, the arrangement of flow elements <NUM> in a greater density and/or the arrangement of flow elements <NUM> having larger dimensioned second ends <NUM> at locations relative to portions of the wound dressing <NUM> that do not correspond to target locations minimizes the degree to which air flowing through the flow path <NUM> passes along the upper surface <NUM> of the drape layer <NUM> at such non-target locations. Resulting, less moisture is acquired by the air flowing through the flow path <NUM> prior to the air reaching a target location (e.g. a portion of the flow path <NUM> overlaying the periwound). Because drier air has a greater capacity to lift moisture from the upper surface <NUM> of the drape layer <NUM>, the decreased moisture level of the air flowing through the flow path <NUM> along the target locations increases the rate at which moisture may be removed from the target locations. In other embodiments, a similar effect of delivering drier air flow to desired target locations may also be accomplished using an optional blocking structure (e.g. a thicker layer of adhesive, an intermediate layer of material, etc.) that is arranged between the spacer structure <NUM> and drape layer <NUM> along the portions of the wound dressing <NUM> that do not correspond to the target locations.

The air displacement device <NUM> may include any number of different air-moving devices (e.g., manual or automatic pump, blower, bellows, etc.). As shown in <FIG>, upon assembly of the wound treatment system <NUM>, a remotely located air displacement device <NUM> is fluidly coupled to the flow path <NUM> via a conduit <NUM>. Alternatively (as described in detail below), the air displacement device <NUM> is provided as a component of a module <NUM> that is supported by the film layer <NUM>, such that the assembled wound treatment system <NUM> defines a single, self-contained device (see, e.g., <FIG>).

Operation of the air displacement device <NUM> is configured to generate a flow of air through the flow path <NUM> of the wound treatment system <NUM>. As illustrated in <FIG>, operation of the air displacement device <NUM> in a positive pressure mode causes air to flow from the air displacement device <NUM>, through the opening <NUM> in the film layer <NUM><NUM>, through the flow path <NUM> defined by the flow elements <NUM> of the spacer structure <NUM>, through one or more vents <NUM>, and into the ambient environment. As shown in <FIG>, operation of the air displacement device <NUM> in a negative pressure mode generates a vacuum that evacuates air through the opening <NUM> in the film layer <NUM> that has been drawn into the flow path <NUM> via the vents <NUM>. During some operations of the wound treatment system <NUM>, the air displacement device <NUM> forces air into (or out from) the flow path <NUM> at a rate of between approximately <NUM>/min and approximately <NUM>/min, which creates a backpressure of approximately 10mmHg.

In embodiments in which the wound treatment system <NUM> is used alongside an additional wound therapy system incorporating a pump or other air moving device, the air displacement device <NUM> may be provided in addition to the pump of the additional wound treatment system (e.g., a NPWT system), such that such that the wound treatment system <NUM> is capable of being operated independently and separately from the NPWT system (or other wound treatment system).

Alternatively, in other embodiments, the pump of the NPWT system (or other additional wound therapy system with which the wound treatment system <NUM> is used) defines the air displacement device <NUM>. As illustrated in <FIG> and <NUM>, in some such embodiments the shared pump is fluidly coupled to a connector <NUM> comprising a NPWT vacuum conduit <NUM> fluidly coupled to a space defined underneath the drape layer <NUM>, and a moisture management conduit <NUM> fluidly coupled to the flow path <NUM>. The connector <NUM> optionally also includes a pressure monitoring conduit that is fluidly coupled to one or both of the treatment space underneath the drape layer <NUM> and the flow path <NUM>.

The shared pump that defines each of the NPWT system (or other additional wound therapy system with which the wound treatment system <NUM> is used) and the air displacement device <NUM> may alternate between being operated to provide treatment using the NPWT system and providing treatment using the wound treatment system <NUM>. In such embodiments, the connector <NUM> optionally includes one or more valves via which the shared pump is selectively fluidly coupled to either the NPWT conduit <NUM> or the moisture management conduit <NUM> based on the desired treatment. For example, the connector <NUM> includes an optional proportional leak valve configured to fluidly couple the pump to moisture management conduit <NUM> while fluidly isolating the NPWT conduit <NUM> during operation of the shared pump to generate pressures in excess of a predetermined threshold (e.g. at negative pressures above 150mmHg). During operation of the shared pump at pressures below the predetermined threshold, the valve is configured to fluidly couple the pump to the NPWT conduit <NUM>, while fluidly isolating the moisture management conduit <NUM>.

During other operations of the wound treatment system <NUM> and NPWT system (or other additional wound therapy system with which the wound treatment system <NUM> is used), the shared pump that defines the air displacement device <NUM> is operated to simultaneously provide treatment using each treatment system. As illustrated by <FIG>, in some such embodiments, the wound treatment system <NUM> is operated in a negative pressure mode concurrently with the operation of the pump to provide NPWT treatment. In such embodiments, an optional valve of the connector <NUM> is selectively actuated such that each of the NPWT conduit <NUM> and moisture management conduit <NUM> are fluidly coupled to the pump.

As shown in <FIG>, the wound treatment system <NUM> can also be operated in the positive pressure mode concurrently with the operation of the pump to provide NPWT treatment. In such embodiments, an outlet of the pump is coupled (e.g. via a valve) to the moisture management conduit <NUM>, with that exhaust airflow resulting from the operation of the pump to generate a vacuum for the NPWT treatment being used as the positive forced airflow that is delivered to the flow path <NUM> via the moisture management conduit <NUM>. In other embodiments, an optional valve is selectively actuated to restrict (e.g. reduce the diameter of) a portion of the NPWT conduit <NUM> located upstream of a Venturi tube (or a selectively openable passageway) that fluidly couples the NPWT conduit <NUM> and moisture management conduit <NUM>. The decrease in pressure resulting from air flow through the restriction in the NPWT conduit <NUM> causes positive forced airflow to be directed through the Venturi tube (or passageway) and into the flow path <NUM>.

As noted above, and representatively illustrated by the wound treatment system <NUM> embodiment of <FIG>, the wound treatment system <NUM> may optionally be formed as an integral self-contained system that may be supported entirely by a patient. In such embodiments, the air displacement device <NUM>, as well as any additional optional components of the wound treatment system <NUM> (e.g. a controller <NUM>, sensors, a power source, a charging circuit, a communications interface, etc.) are housed in an optional module <NUM>. The module <NUM> may optionally also support a patient interface comprising a display and/or user inputs (e.g., buttons) via which information may be provided to and/or received from a user during operation of the wound treatment system <NUM>. In embodiments in which the module <NUM> is configured to operate the wound treatment system <NUM> in the negative pressure mode and/or in embodiments in which the wound treatment system <NUM> is used in conjunction with a NPWT system, the module <NUM> may also contain a reservoir (e.g., an absorbent material, a canister, etc.) configured to store fluid that has been evaporated from the wound dressing <NUM> and/or that is evacuated from the treatment space defined underneath the wound dressing <NUM> and/or any other number of components of the additional wound therapy system.

The module <NUM> optionally includes an engagement structure configured allow the module <NUM> to be sealingly secured around (e.g. adjacent to, surrounding, etc.) an outer periphery of the opening <NUM> in the film layer <NUM> via an engagement to an optional connector <NUM> supported relative to the film layer <NUM>. In other embodiments, the module <NUM> may also be secured directly to the film layer <NUM> using adhesive, welding, etc. In embodiments in which the module <NUM> is intended to be reused with additional wound dressings <NUM>, bacterial and/or hydrophobic filters <NUM> are optionally provided between the opening <NUM> in the film layer <NUM> and an inlet of the module <NUM>. For example, filters <NUM> may be attached to any one or more of the opening <NUM> in the film layer <NUM>, the connector <NUM>, and the engagement structure of the module <NUM> to prevent fluid and/or bacterial ingress and contamination of the module <NUM> during use of the wound treatment system <NUM> and/or during attachment or removal of the module <NUM> to or from wound dressing <NUM>.

Various operations of the wound treatment system <NUM> may be controlled by an optional controller <NUM> (shown, e.g., in <FIG>). For example, the controller <NUM> may turn the air displacement device <NUM> on/off, and/or can be used to vary the speed at which the air displacement device <NUM> is operated. The controller <NUM> may also provide selective control over the actuation of any optional valves of the connector <NUM> during operation of the wound treatment system <NUM> (e.g. to switch operation of the air displacement device <NUM> between positive and negative pressure modes, to switch between the type of treatment being provided during operation of the wound treatment system <NUM> in conjunction with an additional wound therapy system, etc.).

The controller <NUM> may be configured to operate the various components of the wound treatment system <NUM> (e.g. the air displacement device <NUM>, valves, etc.) based on a variety of different inputs received from any number of different sources. For example, in some embodiments, the controller <NUM> may operate the wound treatment system <NUM> based on inputs received from a user. In other embodiments, the controller <NUM> may be configured to operate the wound treatment system <NUM> in accordance to one or more preprogrammed modes stored in a memory of the controller <NUM>. For example, the controller <NUM> may operate the wound treatment system <NUM> in an alternating pressure mode, in which operation of the air displacement device <NUM> is periodically varied between operation in the positive pressure mode, and operation in the negative pressure mode. Such periodic alternation between positive and negative air flow may advantageously be used disrupt regions of dense flow within the treatment space underneath the wound dressing <NUM> and to allow moisture to be removed more uniformly from the wound.

In yet other embodiments, the controller <NUM> is configured to operate the wound treatment system <NUM> responsive to readings or measurement obtained from one or more sensors (e.g. moisture sensor, humidity sensor, pressure sensor, etc.) incorporated into the wound treatment system <NUM>. According to an exemplary embodiment, the wound treatment system <NUM> includes a moisture level sensor assembly comprising one or more moisture indicators and an optical reader configured to detect changes in the indicators. Given that the fluid capacity of and/or fluid levels within the wound dressing <NUM> may vary over time, the indicators are advantageously selected to be capable of providing a dynamic, two-way (i.e. reversible), near real-time indication as to both increases and decreases in moisture levels within the wound dressing <NUM> over the course of use of the wound treatment system <NUM>.

One non-limiting example of such a reversible, dynamic indicator that may be used in the wound treatment system <NUM> is described in more detail in co-pending application <CIT> and titled "FLUID STATUS INDICATOR FOR A WOUND DRESSING," the entirety of which is incorporated herein by reference. In addition to providing a dynamic representation of moisture levels in the treatment space underneath the wound dressing <NUM>, the indicators described in the above referenced co-pending application also advantageously are positionable entirely underneath the wound dressing <NUM> (i.e. do not extend through the drape layer <NUM>). Such an incorporation of indicators into the wound treatment system <NUM> allows the wound dressing <NUM> to remain integral and sealed, and thus advantageously minimizes the risk of exudates, or other fluids or substances from the treatment space underneath the wound dressing <NUM>, contaminating the components of the optionally included module <NUM>.

The moisture indicators are incorporated into (i.e. positioned in direct contact with) one or both of the drape layer <NUM> and an additional dressing layer (e.g., an absorbent layer <NUM>, a manifold layer <NUM>, etc.), so as to be capable of dynamically responding to changes in moisture levels within the wound dressing <NUM> (e.g. changes in the fluid capacity of the absorbent layer <NUM>, moisture levels at a portions of the drape layer <NUM> overlaying the periwound, etc.). The indicators are advantageously positioned directly below the drape layer <NUM> to facilitate the ability of the optical reader to detect changes in the visual appearance of the indicators through the drape layer <NUM>. A fusible fiber (or other attachment mechanism) optionally secures the indicators relative to the wound dressing <NUM> to ensure contact of the indicators with the absorbent layer <NUM> and/or to ensure that the indicators are aligned relative to the module <NUM> such that visual transformations of the indicators are capable of being detected by the optical reader. The optical reader is optionally incorporated into the module <NUM>, or is otherwise positionable relative to the upper surface of the wound treatment system <NUM>.

During some uses of the wound treatment system <NUM>, the controller <NUM> is optionally configured to operate the air displacement device <NUM> in a manner configured to minimize power consumption. For example, during the operation of the wound treatment system <NUM> to prevent moisture levels from exceeding a static fluid capacity of a wound dressing <NUM>, the controller <NUM> may optionally be configured to initiate operation of the air displacement <NUM> to generate airflow through the flow path <NUM> only in response to the detection of a visual transition of an indicator indicative of the moisture level in the treatment space underneath the wound dressing <NUM> being equal to, or exceeding, a predetermined upper threshold moisture level. Additionally, or alternatively, in some embodiments the controller <NUM> may optionally be configured to initiate operation of the air displacement <NUM> to generate airflow through the flow path <NUM> in response to the detection of a visual transition of an indicator indicative of the moisture level at the periwound being equal to, or exceeding, a predetermined upper threshold moisture level.

Upon detecting (e.g. via a visual transition of the indicators) that the moisture level has decreased to a level equal to or below an intermediate moisture level, the controller <NUM> is optionally configured to reduce the speed at which the air displacement device <NUM> is operated. Once the moisture level within the treatment space has reached a level equal to or below a predetermined lower threshold (e.g. between approximately <NUM>% and less than approximately <NUM>% of the fluid capacity of the wound dressing <NUM>), the controller <NUM> ceases operation of the air displacement device <NUM> to save power until such a time when the moisture level in the treatment space (e.g. a moisture level of an optional absorbent layer <NUM>, a moisture level at the periwound, etc.) is detected to again be equal to or greater than the upper predetermined threshold. Such selective operation of the air displacement device <NUM> may continue one or more times during the operation of the wound treatment system <NUM>.

In some embodiments, the controller <NUM> may be configured to continuously receive readings and measurements from one or more sensors (e.g., from a moisture level sensor assembly). Alternatively-to further conserve power-the controller <NUM> may instead be configured to selectively obtain sensor readings only at predetermined intervals (e.g., every <NUM>-<NUM> minutes). In some such embodiments, the predetermined interval at which the sensor readings are obtained may vary in response to the detection of various threshold sensor readings. For example, the controller <NUM> may be configured to obtain moisture level readings at a more frequent interval following the detection (using, e.g., the moisture level sensor assembly) that a moisture level underneath the wound dressing <NUM> is equal to, or exceeds, an upper moisture level threshold.

In various embodiments, the air displacement device <NUM> optionally comprises a plurality of independently operable air displacement devices <NUM> that are fluidly coupled at various locations to the flow path <NUM> around (e.g. adjacent to, surrounding, etc.) the outer peripheries of various openings <NUM> in the film layer <NUM>. In such embodiments, the operation of some or all of the air displacement devices <NUM> is optionally independently controllable, allowing moisture levels to be managed as needed at specific target areas along the wound dressing <NUM>. In some embodiments, each individual air displacement device <NUM> is individually controllable responsive to a moisture level reading (or other sensed condition) obtained from a moisture indicator (or other sensor) positioned at a location relative to the wound that corresponds to the location at which the respective air displacement device <NUM> is positioned. In addition to allowing airflow to be directed to specific desired target locations, such selective activation of only those air displacement devices <NUM> that are needed to provide the desired delivery of airflow also further assists in decreasing the power consumption of the wound treatment system <NUM>.

The construction and arrangement of the systems and methods as shown in the various exemplary embodiments are illustrative only. Although only a few embodiments have been described in detail in this disclosure, many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.). For example, the position of elements can be reversed or otherwise varied and the nature or number of discrete elements or positions can be altered or varied. The order or sequence of any process or method steps can be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes, and omissions can be made in the design, operating conditions and arrangement of the exemplary embodiments.

Claim 1:
A wound treatment system (<NUM>), comprising:
a wound dressing (<NUM>) comprising a drape layer (<NUM>), and a moisture management system (<NUM>) comprising:
a film layer (<NUM>);
a spacer assembly comprising:
one or more flow elements (<NUM>) each having an outer surface which extends between a first end (<NUM>) and a second end (<NUM>), the first ends being located adjacent to and extend downwards relative to a lower surface (<NUM>) of the film layer (<NUM>), and the second ends (<NUM>) being located adjacent to and extending upwards relative to the upper surface (<NUM>) of the drape layer (<NUM>);
the spacer assembly defining a space between the lower surface (<NUM>) of the film layer (<NUM>) and the upper surface (<NUM>) of the drape layer (<NUM>) defining a flow path (<NUM>) between the upper and lower surfaces (<NUM>, <NUM>) and the one or more flow elements (<NUM>)
and
an air displacement device (<NUM>) sealingly engaged with an opening (<NUM>) formed in and extending through the film layer (<NUM>) and configured to cause air to flow through the flow path (<NUM>);
wherein the spacer assembly and film layer (<NUM>) define a monolithic structure;
wherein the lower surface (<NUM>) of the film layer (<NUM>) is embossed to define the one or more flow elements (<NUM>) as raised portions (<NUM>) of the lower surface (<NUM>), and/or the upper surface (<NUM>) of the film layer (<NUM>) is debossed to define the one or more flow elements (<NUM>) as downwardly projecting, debossed portions of the upper surface (<NUM>) of the film layer (<NUM>).