Patent Description:
Negative pressure wound therapy (NPWT) is a type of wound therapy that involves applying negative pressure (relative to atmospheric pressure) to a wound bed to promote wound healing. Typically, a dressing is sealed over a wound bed and air is pumped out of the dressing to create a negative pressure at the wound bed. In some NPWT systems, wound exudate and other fluid is pumped out of the dressing and collected by a therapy system.

In other NPWT systems, air is pumped out of the dressing while the dressing is used to absorb fluid from the wound. In some such systems, it is preferable for air to be drawn to the pump while fluid or other wound exudate is prevented from reaching the pump, such that the pump is protected from contamination or other damage that may be caused by such fluid or other exudate contacting the pump. Accordingly, assemblies for protecting the pump from contact with fluid or other wound exudate while also allowing the pump to remove air from the dressing are desirable.

One implementation of the present invention is a dressing as set out in claim <NUM>. There is also provided a system comprising: the dressing; a tube coupled to the dressing; a connection assembly, wherein the tube is coupled to the dressing by the connection assembly; a pump pneumatically communicable with the dressing via the tube; and a dye in the tube configured to provide an indication representative of fluid in the tube.

Referring now to <FIG>, a negative pressure wound therapy (NPWT) system <NUM> is shown. The NPWT system <NUM> includes a pump <NUM> pneumatically communicable with a dressing <NUM> via tube <NUM>. The tube <NUM> is coupled to the dressing <NUM> by a connection assembly <NUM>. The dressing <NUM> is shown as sealed over a wound bed <NUM>. The wound bed <NUM> is a tissue wound of a patient, for example a laceration, burn, sore, trauma wound, chronic wound, etc..

The dressing <NUM> allows a negative pressure to be maintained at the wound bed <NUM> while absorbing fluid from the wound bed <NUM>. The dressing <NUM> thereby provides both negative pressure and a high level of fluid absorption. The dressing <NUM> is shown to include drape <NUM>, a manifold layer <NUM>, a wound contact layer <NUM>, and absorbent deposits <NUM>. It should be understood that the dressing <NUM> is one example of an absorbent negative pressure dressing and that many embodiments are possible, for example as shown and described in <CIT>.

The drape <NUM> is configured to seal the wound contact layer <NUM>, the manifold layer <NUM>, and the absorbent deposits <NUM> over the wound bed <NUM>. For example, the drape <NUM> may include an adhesive ring coupleable to the patient's skin surrounding the wound bed <NUM>. The drape <NUM> may include a material that substantially prevents leaking of air therethrough to facilitate creation and maintenance of a negative pressure at the manifold layer <NUM> (i.e., in a volume between the drape <NUM> and the wound bed <NUM>). The drape <NUM> may also include a material with a high moisture vapor transfer rate to facilitate evaporation of fluid from the absorbent deposits <NUM> to the ambient air through the drape <NUM>.

The wound contact layer <NUM> provides an interface between the dressing <NUM> and a wound. The wound contact layer <NUM> may be configured to prevent ingrowth of the wound bed <NUM> to the dressing and to facilitate removal of the dressing <NUM> while minimizing damage to the healing tissue of the wound bed <NUM>. The wound contact layer <NUM> includes a film, for example a silicone film. The wound contact layer <NUM> may be perforated or otherwise formed to allow for the flow of air and fluid therethrough.

The manifold layer <NUM> is configured to allow airflow therethrough to facilitate the distribution of negative pressure across the wound bed <NUM>. The manifold layer <NUM> may include an open-celled foam, for example a foam material marketed as GRANUFOAM™ by ACELITY™. The manifold layer <NUM> is also configured to allow fluid to flow therethrough, from the wound bed <NUM> to the absorbent deposits <NUM>.

The absorbent deposits <NUM> are configured to absorb fluid, for example wound exudate from the wound bed <NUM>. The absorbent deposits <NUM> may include a superabsorbent material. Various arrangements and configurations of the absorbent deposits <NUM> are included in various embodiments. The absorbent deposits <NUM> may be included as a superabsorbent laminate positioned between the drape <NUM> and the manifold layer <NUM>, with channels extending therethrough to allow airflow therethrough. It should be understood that various configurations of absorbent dressings <NUM> are contemplated by the present disclosure and can be compatible with the connection assembly <NUM>, which is described in detail with reference to <FIG>. The absorbent deposits <NUM> and the dressing <NUM> are configured such that the absorbent deposits <NUM> absorb fluid to approximately a full capacity of the absorbent deposits <NUM> before fluid passes into or is absorbed by the connection assembly <NUM> as described below.

The connection assembly <NUM> is configured to couple the dressing <NUM> to a tube <NUM>, which is coupled to a pump <NUM>. The connection assembly <NUM> is positioned at a hole extending through the drape <NUM> such that the connection assembly <NUM> is in fluid communication with the manifold layer <NUM>. As shown in <FIG> and described in detail with reference thereto, the connection assembly <NUM> is configured to allow airflow between the manifold layer <NUM> and the pump <NUM> while restricting the flow of fluid therebetween. The tube <NUM> is configured to provide an airway that allows air to flow from the connection assembly <NUM> to the pump <NUM>. In some examples, for example as shown in <FIG> and described in detail with reference thereto, the tube <NUM> is configured to prevent the flow of fluid therethrough.

The pump <NUM> is operable to pump air out of the dressing <NUM> via the tube <NUM> to create and maintain a negative pressure at the wound bed <NUM>. The pump <NUM> may be electrically powered and the NPWT system <NUM> includes power systems and control circuitry to power and control operation of the pump <NUM>. For example, the NPWT system <NUM> may include one or more pressure sensors or various other sensors that collect data used to control the pump <NUM> to maintain a negative pressure at the wound bed <NUM>. The pump <NUM> may be manually-powered, such that a user may manipulate the pump <NUM> to draw air out of the dressing <NUM> as desired by the user. For example, the pump <NUM> may be spring-loaded to gradually pull air from the dressing <NUM> for a duration of time following a compression of the pump <NUM> by the user.

The NPWT system <NUM> is thereby configured to provide a negative pressure at the wound bed <NUM> while also facilitating absorption of fluid from the wound bed <NUM> by the dressing <NUM>.

Referring now to <FIG>, an various views of the connection assembly <NUM> are shown. As shown in <FIG>, the connection assembly <NUM> includes a connection pad <NUM> and an absorbent manifolding structure <NUM>.

The connection pad <NUM> is configured to couple the dressing <NUM> to the tube <NUM>. The connection pad <NUM> includes an outer ring <NUM> that surrounds a center dimple <NUM>. The outer ring <NUM> is configured to be coupled to the drape <NUM>. When the outer ring <NUM> is coupled to the drape, the center dimple <NUM> extends away from the drape <NUM>. The center dimple <NUM> thereby defines an inner volume <NUM> between the center dimple <NUM> and a plane defined by the outer ring <NUM>. The connection pad <NUM> also includes a tube conduit <NUM> configured to receive the tube <NUM>.

The absorbent manifolding structure (disc, insert, layer, etc.) <NUM> is formed to have a shape that substantially matches a shape of the inner volume <NUM>. Accordingly, the absorbent manifolding structure <NUM> is configured to fit substantially within the inner volume <NUM> and the inner volume <NUM> is configured to receive the absorbent manifolding structure <NUM>. In the example shown, the absorbent manifolding structure <NUM> substantially fills the inner volume <NUM>. By fitting within the inner volume <NUM>, the absorbent manifolding structure <NUM> can be selectively included or not included with the NPWT system <NUM> without requiring a change in the design or manufacturing process for the dressing <NUM> or the connection pad <NUM>.

As shown in <FIG>, the absorbent manifolding structure <NUM> is positioned in the inner volume <NUM> and positioned between the tube conduit <NUM> and the dressing <NUM> such that airflow from the dressing <NUM> to the tube <NUM> must pass through the absorbent manifolding structure <NUM>. The absorbent manifolding structure <NUM> is configured to allow airflow therethrough (i.e., between the dressing <NUM> and the tube <NUM>) when the absorbent manifolding structure <NUM> has not absorbed a threshold amount of fluid, and to prevent airflow therethrough when the absorbent manifolding structure <NUM> has absorbed more than a threshold amount of fluid.

According to the illustrated embodiments, the absorbent manifolding structure <NUM> is shown to include a sintered polymer material (e.g., sintered polyethylene) mixed with a superabsorbent material. The sintered polymer material is formed with pores (channels, spaces, airways, etc.) such that air and fluid can pass through the sintered polymer material. Each pore may have a size within a range between approximately <NUM> microns and <NUM> microns. The superabsorbent material is dispersed in the sintered polymer material and is configured to absorb fluid and swell when in contact with fluid. In the absorbent manifolding structure <NUM>, when the superabsorbent material swells to absorb fluid (e.g., more than a threshold amount of fluid), the swollen superabsorbent material closes (gel-blocks, fills, blocks, obstructs, etc.) the pores of the sintered polymer material and restricts the flow of air and fluid through the absorbent manifolding structure <NUM>. The absorbent manifolding structure <NUM> is thereby configured to allow airflow therethrough when substantially dry, while substantially preventing the flow of air and fluid therethrough when more than a threshold amount of fluid is absorbed by the sintered polymer material. The air flow through the absorbent manifolding structure <NUM> may be between approximately <NUM>/min and <NUM>/min at an air pressure of <NUM> Pa. The absorbent manifolding structure <NUM> thereby facilitates the pump <NUM> in drawing a negative pressure at the dressing <NUM> while substantially preventing fluid from the wound bed <NUM> from reaching the pump <NUM> (damaging the pump <NUM>, contaminating the pump <NUM>, etc.).

The blocking effect provided by the superabsorbent material may be localized within the absorbent manifolding structure <NUM> to areas (regions, spots, etc.) of the absorbent manifolding structure <NUM> in contact with fluid. For example, a first region of the absorbent manifolding structure <NUM> may include swollen superabsorbent (having absorbed fluid) that blocks the flow of air and fluid through the first region, while a second region of the absorbent manifolding structure <NUM> is substantially dry (i.e., not in contact with a significant amount of fluid) and therefore allows air to flow through the second region. This regional independence may allow airflow through the absorbent manifolding structure <NUM> to remain open for an increased amount of time.

In some unclaimed examples, the absorbent manifolding structure <NUM> includes a fluid-activated dye. In such examples, the dye is released and/or changes color in response to contact with fluid. The connection pad <NUM> may be translucent or transparent such that the dye is visible through the connection pad <NUM>. The absorbent manifolding structure <NUM> may thereby be configured to provide a visual indication that the absorbent manifolding structure <NUM> has absorbed fluid to a user (patient, caregiver, etc.). In the claimed system, the tube <NUM> includes a fluid-activated dye configured to release and/or change color in response to contact with fluid, such that a change in color in the tube indicates that fluid has passed through the absorbent manifolding structure <NUM>. The inclusion of a dye may thereby facilitate a user in determining when to remove the dressing <NUM> and/or make other changes to wound therapy.

Referring now to <FIG>, a second example of the connection assembly <NUM> is shown which is useful for understanding the claimed subject matter but does not form part of the claimed subject matter. As shown in <FIG>, the connection assembly <NUM> includes the connection pad <NUM>, a felted foam layer <NUM>, and a gel-blocking sintered polymer layer <NUM> positioned between the connection pad <NUM> and the felted foam layer <NUM>. As shown in <FIG>, the felted foam layer <NUM> and the gel-blocking sintered polymer layer <NUM> are positioned under the connection pad <NUM> (i.e., between the center dimple <NUM> and the dressing <NUM>. In other unclaimed examples, the felted foam layer <NUM> and the gel-blocking sintered polymer layer <NUM> are formed to fit within the center dimple <NUM> similar to the examples of <FIG>.

The felted foam layer <NUM> is configured to allow airflow therethrough and to resist the flow of fluid therethrough such that fluid in the dressing <NUM> is directed to the absorbent deposits <NUM> or other wicking or absorbent structure of the dressing <NUM> when absorbent capacity is available in the dressing <NUM>. The felted foam layer <NUM> thereby substantially minimizes or restricts the flow of fluid into the connection assembly <NUM> when absorbent capacity is available in the dressing <NUM>. When the dressing is full (i.e., when the absorbent capacity of the dressing <NUM> is met), the felted foam layer <NUM> is configured to allow fluid to pass therethrough from the manifold layer <NUM> to the gel-blocking sintered polymer layer <NUM>. Accordingly, passage of fluid through the felted foam layer <NUM> is associated with a full dressing <NUM>. The felted foam layer <NUM> may include three to five times felted foam, where the foam is a same or similar foam as the manifold layer <NUM> (i.e., processed to be permanently compressed to a fraction of the original thickness of the foam material of the manifold layer <NUM>).

The gel-blocking sintered polymer layer <NUM> is configured to allow air to flow therethrough when the gel-blocking sintered polymer layer <NUM> has absorbed less than a threshold amount of fluid, and to prevent air and fluid from flowing therethrough when the gel-blocking sintered polymer layer <NUM> has absorbed more than a threshold amount of fluid. The gel-blocking sintered polymer layer <NUM> includes a sintered polymer material (e.g., sintered polyethylene) mixed with a superabsorbent material. The sintered polymer material is formed with pores (channels, spaces, airways, etc.) such that air and fluid can pass through the sintered polymer material. Each pore may have a size within a range between approximately <NUM> microns and <NUM> microns. The superabsorbent material is dispersed in the sintered polymer material and is configured to absorb fluid and swell when in contact with fluid. When the superabsorbent material of the gel-blocking sintered polymer layer <NUM> swells to absorb fluid (e.g., more than a threshold amount of fluid), the swollen superabsorbent material closes (gel-blocks, fills, blocks, obstructs, etc.) the pores of the sintered polymer material and restricts the flow of air and fluid through the absorbent manifolding structure <NUM>. The absorbent manifolding structure <NUM> is thereby configured to allow airflow therethrough when substantially dry, while substantially preventing the flow of air and fluid therethrough when more than a threshold amount of fluid is absorbed by the sintered polymer material. The gel-blocking sintered polymer layer <NUM> may also include a fluid-activated dye configured to provide a visual indication of fluid reaching the gel-blocking sintered polymer layer <NUM>.

The gel-blocking effect provided by the superabsorbent material may be localized within the gel-blocking sintered polymer layer <NUM> to regions (areas, spots, etc.) of the gel-blocking sintered polymer layer <NUM> in contact with fluid. For example, a first region of the gel-blocking sintered polymer layer <NUM> may include swollen superabsorbent (having absorbed fluid) that blocks the flow of air and fluid through the first region, while a second region of the gel-blocking sintered polymer layer <NUM> is substantially dry (i.e., not in contact with a significant amount of fluid) and therefore allows air to flow through the second region. This regional independence may allow airflow through the gel-blocking sintered polymer layer <NUM> to remain possible for an increased amount of time.

Referring now to <FIG>, a third example of the connection assembly <NUM> is shown which is useful for understanding the claimed subject matter but does not form part of the claimed subject matter. As shown in <FIG>, the connection assembly <NUM> includes the connection assembly, the felted foam layer <NUM> and a perforated superabsorbent laminate <NUM> positioned between the felted foam layer <NUM> and the perforated superabsorbent laminate <NUM>. As shown in <FIG>, the felted foam layer <NUM> and the perforated superabsorbent laminate <NUM> are positioned under the connection pad <NUM> (i.e., between the center dimple <NUM> and the dressing <NUM>. In other unclaimed examples, the felted foam layer <NUM> and/or the perforated superabsorbent laminate <NUM> are formed to fit within the center dimple <NUM> similar to the examples of <FIG>.

The perforated superabsorbent laminate <NUM> is configured to allow air to flow therethrough when the perforated superabsorbent laminate <NUM> has absorbed less than a threshold amount of fluid, and to prevent air and fluid from flowing therethrough when the perforated superabsorbent laminate <NUM> has absorbed more than a threshold amount of fluid. The perforated superabsorbent laminate <NUM> includes one or more membranes (e.g., films, hydrophilic membranes, etc.) and a superabsorbent material. For example, in one unclaimed examples, the perforated superabsorbent laminate <NUM> includes a hydrophilic membrane layer, a superabsorbent material positioned on the hydrophilic membrane layer, and a film layer coupled to the hydrophilic foam layer and configured to confine the superabsorbent material between the film layer and the hydrophilic membrane layer. Various examples of super-absorbent laminates are described in <CIT>.

In the example of <FIG>, the perforated superabsorbent laminate <NUM> includes multiple perforations (holes, channels, airways, pores, etc.) extending therethrough (e.g., approximately <NUM> perforations, approximately <NUM> perforations, approximately <NUM> perforations, etc.). The perforations may have a diameter between approximately <NUM> and <NUM> and may be spaced to maintain structural integrity of the perforated superabsorbent laminate <NUM>. For example, the perforations may be distributed within a radial spacing of approximately <NUM>-<NUM> over the perforated superabsorbent laminate <NUM>. The perforations allow air to flow through the perforated superabsorbent laminate <NUM> via the perforations.

When the superabsorbent material of the perforated superabsorbent laminate <NUM> absorbs fluid, the superabsorbent material swells, including into the perforations to narrow or close (block, fill, shut) the perforations. When the superabsorbent material is swollen to close all perforations, the perforated superabsorbent laminate <NUM> substantially prevents the flow of air and fluid through the perforated superabsorbent laminate <NUM>. Additionally, swelling of the superabsorbent material may be localized to regions where fluid is in contact with the superabsorbent laminate <NUM> (i.e., where fluid has passed through the felted foam layer <NUM>). Accordingly, in one example, a first region of the superabsorbent laminate <NUM> is exposed to fluid and the superabsorbent material at the first region is swollen to block one or more perforations of the first region, while a second region of the superabsorbent laminate is not exposed to fluid and the superabsorbent material at the second region is not swollen such that perforations at the second region remain open. In this example, airflow is blocked at the first region where airflow is allowed via the perforations of the second region. Accordingly, the perforations may be characterized as an array of fluidly-activated micro-valves.

Referring now to <FIG>, a fourth example of the connection assembly <NUM> is shown which is useful for understanding the claimed subject matter but does not form part of the claimed subject matter. As shown in <FIG>, the connection assembly <NUM> includes the connection pad <NUM>, the felted foam layer <NUM>, a first microporous film layer <NUM> coupled to the felted foam layer <NUM>, and a second microporous film layer <NUM> positioned between the felted foam layer <NUM> and the connection pad <NUM>. The felted foam layer <NUM> is positioned between the first microporous film layer <NUM> and the second microporous film layer <NUM>. The first microporous film layer <NUM> and the second microporous film layer <NUM> are configured to allow air to flow therethrough. The first microporous film layer <NUM> and the second microporous film layer <NUM> are also configured to resist a flow of fluid therethrough (i.e., allows a low rate of fluid to pass therethrough). The combination of the first microporous film layer <NUM>, the felted foam layer <NUM>, and the second microporous film layer <NUM>, arranged in series between the manifold layer <NUM> and the connection pad <NUM>, thereby restricts (limits, reduces, substantially prevents) fluid from passing through all three layers <NUM>, <NUM>, <NUM> to reach the tube <NUM>. The first microporous film layer <NUM>, the felted foam layer <NUM>, and the second microporous film layer <NUM> may be positioned below the connection pad <NUM> as shown in <FIG> or may be positioned in the inner volume <NUM> of the connection pad <NUM> similar to the embodiments of <FIG>.

Referring now to <FIG>, a fifth example of the connection assembly <NUM> is shown which is useful for understanding the claimed subject matter but does not form part of the claimed subject matter. As shown in <FIG>, the connection assembly <NUM> includes the connection pad <NUM>, the felted foam layer <NUM>, a superabsorbent fiber layer <NUM> positioned between the felted foam layer <NUM> and the connection pad <NUM> and a fusible fiber layer <NUM> positioned between the felted foam layer <NUM> and the connection pad <NUM>. The fusible fiber layer <NUM> is configured to couple the superabsorbent fiber layer <NUM> to the felted foam layer <NUM>. In some manufacturing processes, the fusible fiber layer <NUM> may be omitted and the superabsorbent fiber layer <NUM> may adhere directly to the felted foam layer <NUM>. The felted foam layer <NUM>, the superabsorbent fiber layer <NUM>, and the fusible fiber layer <NUM> may be positioned below the connection pad <NUM> as shown in <FIG> and/or may be positioned in the inner volume <NUM> of the connection pad <NUM> similar to the example of <FIG>.

The superabsorbent fiber layer <NUM> is open to airflow when dry, i.e., such that air can flow therethrough from the felted foam layer <NUM> to the connection pad <NUM>. The superabsorbent fiber layer <NUM> is configured to absorb fluid and swell to retain the fluid. When fluid is absorbed by the superabsorbent fiber layer <NUM>, the swelling of the superabsorbent fiber layer <NUM> closes airways through the superabsorbent fiber layer <NUM>, thereby substantially preventing airflow through the superabsorbent fiber layer <NUM>. Various regions of the superabsorbent fiber layer <NUM> may swell and block airflow independent, for example such that fluid has been absorbed and airflow is blocked at a first region of the superabsorbent fiber layer <NUM> while fluid has not been absorbed and air can flow through a second region of the superabsorbent fiber layer <NUM>. The superabsorbent fiber layer <NUM> may include a superabsorbent fiber sold as Oasis Type <NUM> Super Absorbent Fibre by Technical Absorbents Limited or a superabsorbent fiber sold as M631/<NUM> by Freudenberg.

Various other examples having a similar arrangement as that shown in <FIG> are also possible. For example, a superabsorbent material (e.g., in a granular form) may be deposited on the felted foam layer <NUM>. The superabsorbent material may be suspended in an organic dry solvent such as a ketone or alcohol and may be coated on the felted foam layer <NUM>, and may behave in a similar manner as the superabsorbent fiber layer <NUM> of <FIG>. The superabsorbent material may be arranged as a cross-linked hydrogel printed (deposited, etc.) on the felted foam layer <NUM> in a pattern that allows airflow therethrough while having sufficient coverage to block the flow of fluid therethrough when swollen. As another example, a perforated hydrogel sheet or a hydrogel coated mesh may be included to allow air to flow through the sheet or mesh when dry and substantially prevent the flow of air and fluid through the sheet or mesh when in contact with at least a threshold amount of fluid.

Referring now to <FIG>, an illustration depicting the behavior of the second example of the connection assembly <NUM> (i.e., as in <FIG>) when in contact with fluid, according to an example which is useful for understanding the claimed subject matter but does not form part of the claimed subject matter. <FIG> shows three frames, arranged in chronological order to show change over time. In the first frame <NUM>, the felted foam layer <NUM> and the gel-blocking sintered polymer layer <NUM> are not exposed to fluid. Accordingly, airflow is permitted through all regions (portions, areas, etc.) of the felted foam layer <NUM> and the gel-blocking sintered polymer layer <NUM>. In the first frame <NUM>, the pump <NUM> can draw air out of the manifold layer <NUM> via the tube <NUM> and connection assembly <NUM> at a maximum airflow rate to establish a negative pressure at the wound bed <NUM>.

Between the first frame <NUM> and the second frame <NUM>, the felted foam layer <NUM> is exposed to fluid <NUM>. For example, a maximum absorption capacity of the dressing <NUM> (e.g., of the absorbent deposits <NUM>) may have been met such that the excess fluid is directed into the felted foam layer <NUM>. The fluid <NUM> has passed through the felted foam layer <NUM> to the gel-blocking sintered polymer layer <NUM>. In response to contact with the fluid <NUM>, the superabsorbent material of the gel-blocking sintered polymer layer <NUM> has swollen in a gel-blocked region <NUM> of the sintered polymer layer <NUM>. The gel-blocked region <NUM> substantially prevents the flow of air and fluid through the gel-blocked region <NUM> of the gel-blocking sintered polymer layer <NUM>. As shown in the second frame <NUM>, the gel-blocked region <NUM> is only a portion of the gel-blocking sintered polymer layer <NUM>. Accordingly, airflow is still permitted through other areas of the gel-blocking sintered polymer layer <NUM> as indicated in the second frame <NUM>. The rate of airflow through the connection assembly <NUM> to the pump <NUM> may be lower in the second frame <NUM> relative to the first frame <NUM>.

Between the second frame <NUM> and the third frame <NUM>, the amount of fluid <NUM> at the felted foam layer <NUM> and the gel-blocking sintered polymer layer <NUM> continues to increase. In the third frame <NUM>, substantially the entirety of the gel-blocking sintered polymer layer <NUM> is exposed to fluid. The superabsorbent material has swollen across substantially the entirety of the gel-blocking sintered polymer layer <NUM>. Accordingly, the gel-blocked region <NUM> has expanded relative to the second frame <NUM> to block airflow through substantially the entirety of the gel-blocking sintered polymer layer <NUM>. The flow of air and fluid through the gel-blocking sintered polymer layer <NUM> (and therefore the connection assembly <NUM>) is thereby substantially prevented.

Referring now to <FIG>, a cross-sectional view of an example of the tube <NUM> is shown, according to an example which is useful for understanding the claimed subject matter but does not form part of the claimed subject matter. The tube <NUM> may be used with various embodiments of the NPWT system <NUM> including with various embodiments of the connection assembly <NUM>. The tube <NUM> is configured to be coupled to the tube conduit <NUM> of the connection pad <NUM> and the pump <NUM>.

As shown in <FIG>, the tube <NUM> includes a hydrophobic outer ring <NUM> and a fluid-activated inner ring <NUM>. A central channel <NUM> extends approximately along a central axis of the fluid-activated inner ring <NUM>. The tube <NUM> is configured to allow airflow therethrough (i.e., through the central channel <NUM>) when the fluid-activated inner ring <NUM> is substantially dry and to block the flow of fluid and air therethrough when the fluid-activated inner ring <NUM> is exposed to a threshold amount of fluid.

In the example of <FIG>, the hydrophobic outer ring <NUM> includes a plasticized PVC or polyurethane tube (e.g., a suitable material for standard medical-grade tubing). The hydrophobic outer ring <NUM> surrounds and is coupled to the fluid-activated inner ring <NUM>. The fluid-activated inner ring <NUM> is positioned within the hydrophobic outer ring <NUM>. The hydrophobic outer ring <NUM> and fluid-activated inner ring <NUM> may make up a full length of the tube <NUM> or may be included as one or more segments of the tube <NUM> (e.g., added as an accessory to an existing tubeset).

In some unclaimed examples, the hydrophobic outer ring <NUM> is configured to swell in response to contact with fluid. For example, the hydrophobic outer ring <NUM> may include a superabsorbent material configured to absorb fluid and swell to retain the fluid. In such examples, the hydrophobic outer ring <NUM> may be configured to resist expansion, i.e., such that the fluid-activated inner ring <NUM> primarily expands into the central channel <NUM> when exposed to fluid. Accordingly, as fluid enters the tube <NUM>, the cross-sectional area of the central channel <NUM> is reduced partially or completely by the fluid-activated inner ring <NUM>, thereby reducing the rate of air or fluid flow through the central channel <NUM> and/or preventing the flow of air or fluid through the central channel <NUM>.

In other unclaimed examples, the fluid-activated inner ring <NUM>, when substantially dry, is configured to provides structural support that prevents the fluid-activated inner ring <NUM> (and, in some examples, the hydrophobic outer ring <NUM>) from collapsing inward due to a pressure differential between the ambient air and the interior of the central channel <NUM> (as established by the pump <NUM>). In such examples, the fluid-activated inner ring <NUM> is configured to soften when in contact with fluid, thereby reducing the rigidity of the fluid-activated inner ring <NUM> and the ability of the fluid-activated inner ring <NUM> to provide structural support for the tube <NUM>. In some such examples, the hydrophobic outer ring <NUM> includes perforations that allow communication of ambient air pressure to the fluid-activated inner ring <NUM>, which may cause the fluid-activated inner ring <NUM> to collapse under a pressure differential between the ambient air and the interior of the central channel <NUM> (i.e., without requiring collapse of the hydrophobic outer ring <NUM>). In other examples, the hydrophobic outer ring <NUM> may collapse under the pressure differential when the structural support of the fluid-activated inner ring <NUM> is reduced.

Accordingly, when the fluid-activated inner ring <NUM> is exposed to a threshold amount of fluid, the pressure differential between the ambient air and the central channel <NUM> causes the fluid-activated inner ring <NUM> (and, in some examples, the hydrophobic outer ring <NUM>) and to collapse inwards, reducing or eliminating a cross-sectional area of the central channel <NUM>. The flow of air and fluid is thereby restricted or prevented by the tube <NUM> in response to fluid entering the tube <NUM>.

In either example, the closing of the central channel <NUM> may be made reversible. For example, the fluid-activated inner ring <NUM> may return to its original form as fluid returns to the dressing <NUM> from the tube <NUM> (e.g., drawn into the superabsorbent deposits <NUM> as fluid from the superabsorbent deposits <NUM> evaporates to the ambient environment).

In the claimed system, the tube <NUM> includes a fluid-activated dye configured to be released and/or to change color in response to exposure to fluid. The tube <NUM> may be transparent or translucent such that the dye is visible in the tube. The dye may thereby facilitate a user in determining when a dressing should be removed and/or planning other modifications to wound therapy for the wound bed <NUM>.

As utilized herein, the terms "approximately," "about," "substantially," and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and are considered to be within the scope of the disclosure.

Claim 1:
A dressing (<NUM>), comprising:
a manifold layer (<NUM>);
a drape (<NUM>) coupled to the manifold layer (<NUM>) and configured to seal the manifold layer over a wound (<NUM>), the drape (<NUM>) having an opening extending therethrough;
a connection pad (<NUM>) positioned at the opening and configured to couple the dressing (<NUM>) to a tube (<NUM>), the connection pad (<NUM>) comprising:
an outer ring (<NUM>) coupled to the drape (<NUM>); and
a center dimple (<NUM>) extending away from the drape (<NUM>) and defining a volume (<NUM>) between the center dimple (<NUM>) and a plane defined by the outer ring (<NUM>); and
an absorbent manifolding structure (<NUM>) positioned between the center dimple (<NUM>) and the manifold layer (<NUM>) and formed to substantially match a shape of the volume (<NUM>), wherein the absorbent manifolding structure (<NUM>) comprises a hydrophobic porous member combined with an air permeable superabsorbent material configured to gel-block upon exposure to fluids.