Patent Application
20210137744
The disclosed technology relates to a wound dressing comprising various spacer layers. The disclosed technology relates to a wound dressing comprising an apertured nonwoven fabric spacer layer or a three dimensional nonwoven spacer layer. The disclosed technology further relates to methods and uses of the wound dressing.
In wound treatment there is a balance between providing a wound dressing to remove wound fluid which can accumulate between the dressing and the skin. A build up of fluid between the wound and the dressing can cause separation of the dressing from the skin. Separation of the dressing from the skin can increase the possibility of the wound being contaminated by microorganisms which can cause infection. However, the dressing should be in place for sufficient time to ensure the body can progress biological process required to heal a wound.
Depending on the nature of the wound, the patient may be immobilized for prolonged periods of time. Immobilization of a patient or neuropathy may also lead to complicating factors such as ulcers (such as a pressure ulcer, or also known as a pressure injury) or bed sores.
Pressure ulcers (may be referred to as “bed sores” or decubitus ulcers) may be developed by individuals confined for an extended period of time to a particular position in a bed or chair. When a person is bed ridden or wheel chair bound due to such causes as an accident, illness, or extensive period of recovery from surgery, the body tends to be immobilized for an extended period of time. It has been noted that pressure ulcers occur most frequently in certain parts of the body, such as the heel and ankle, the trochanter, the sacrum, the scapulae, at the elbows, knees, occiput, ischial tuberosites and at the coccyx. As presently understood, the weight overlying these body parts exerts sufficient pressure on the underlying soft tissue layers to cause an interruption of the flow of blood to and through the soft tissue layers causing the development of a condition generally referred to as pressure ulcers.
The treatment of open or chronic wounds that are too large to spontaneously close or otherwise fail to heal by means of applying negative pressure to the site of the wound is well known in the art. Negative pressure wound therapy (NPWT) systems currently known in the art commonly involve placing a cover that is impermeable or semi-permeable to fluids over the wound, using various means to seal the cover to the tissue of the patient surrounding the wound, and connecting a source of negative pressure (such as a vacuum pump) to the cover in a manner so that negative pressure is created and maintained under the cover. It is believed that such negative pressures promote wound healing by facilitating the formation of granulation tissue at the wound site and assisting the body's normal inflammatory process while simultaneously removing excess fluid, which may contain adverse cytokines and/or bacteria. However, further improvements in NPWT are needed to fully realize the benefits of treatment.
Many different types of wound dressings are known for aiding in NPWT systems. These different types of wound dressings include many different types of materials and layers, for example, gauze, pads, foam pads or multi-layer wound dressings. One example of a multi-layer wound dressing is the PICO dressing, available from Smith & Nephew, which includes a superabsorbent layer beneath a backing layer to provide a canister-less system for treating a wound with NPWT. The wound dressing may be sealed to a suction port providing connection to a length of tubing, which may be used to pump fluid out of the dressing and/or to transmit negative pressure from a pump to the wound dressing.
In one embodiment the disclosed technology relates to a wound dressing, and methods and uses of employing the wound dressing. Some embodiments may mitigate/reduce or prevent ulcer formation during wound healing. Some embodiments of the wound dressing may be adapted for use in negative pressure wound therapy.
As used herein, the transitional term “comprising,” which is synonymous with “including,” “containing,” or “characterized by,” is inclusive or open-ended and does not exclude additional, un-recited elements or method steps. However, in each recitation of “comprising” herein, it is intended that the term also encompasses, as alternative embodiments, the phrases “consisting essentially of” and “consisting of,” where “consisting of” excludes any element or step not specified and “consisting essentially of” permits the inclusion of additional un-recited elements or steps that do not materially affect the basic and novel characteristics of the composition, method or use under consideration.
In some embodiments, a wound treatment apparatus can comprise a wound dressing. The wound dressing can comprise a spacer layer comprising a first nonwoven fabric layer comprising a first fibrous base layer and an interconnected first fibrous face layer, wherein a plurality of channels are disposed between the first fibrous base layer and the first fibrous face layer, and a second nonwoven fabric layer comprising a second fibrous base layer and an interconnected second fibrous face layer, wherein a plurality of channels are disposed between the second fibrous base layer and the second fibrous face layer, wherein the second nonwoven fabric layer is disposed over the first nonwoven fabric layer such that the second fibrous face layer of the second nonwoven fabric is positioned over the first fibrous face layer of the first nonwoven fabric, a cover layer positioned over the spacer layer.
The apparatus of the preceding paragraph may also include any combination of the features described in the following paragraphs, among others described herein. Each of the features described in the following paragraphs may also be part of another embodiment that does not necessarily include all of the features of the previous paragraph.
The plurality channels of the first or second nonwoven fabric layers can extend across an entire length of the first and second nonwoven fabric layers.
The channels of the first nonwoven fabric layer can extend in a first direction and the channels of the second nonwoven fabric layer extend in a second direction.
The first direction can be parallel to the second direction.
The first direction can be perpendicular to the second direction.
The plurality of channels of the second nonwoven fabric layer can be disposed directly over the plurality of channels of the first nonwoven fabric layer.
The plurality of channels of the second nonwoven fabric layer can be offset from the plurality of channels of the first nonwoven fabric layer.
Each of the plurality of channels of the first and second nonwoven fabric layers can have a diameter of from about 0.5 mm to about 5 mm.
The base layer and the face layer of the first and/or second nonwoven fabric layers can be hydroentangled.
The face layer of the first and/or second nonwoven fabric layers can be hydrophilic.
The base layer of the first and/or second nonwoven fabric layers can be hydrophobic.
The wound treatment apparatus can further comprise a pump and a suction port for applying negative pressure to a wound site through an orifice in the cover layer.
The spacer layer can be configured to remain open upon application of negative pressure to the wound treatment apparatus.
The wound treatment apparatus can further comprise an absorbent layer for absorbing wound exudate, the absorbent layer positioned over the spacer layer.
The absorbent layer can comprise a non-woven material containing superabsorbent particles or fibers.
The wound treatment apparatus can further comprise a masking layer positioned between the absorbent layer and cover layer.
The wound treatment apparatus can further comprise a second spacer layer positioned over the absorbent layer, wherein the second spacer layer can comprise a third nonwoven fabric layer comprising a third fibrous base layer and an interconnected third fibrous face layer, wherein a plurality of channels are disposed between the third fibrous base layer and the third fibrous face layer, and a fourth nonwoven fabric layer comprising a fourth fibrous base layer and an interconnected fourth fibrous face layer, wherein a plurality of channels are disposed between the fourth fibrous base layer and the fourth fibrous face layer, wherein the fourth nonwoven fabric layer is disposed over the third nonwoven fabric layer such that the fourth fibrous face layer of the fourth nonwoven fabric is in contact with the third fibrous face layer of the third nonwoven fabric.
The cover layer can comprise an orifice.
The cover layer can comprise a moisture vapor permeable material.
The channels can be rounded channels.
The channels can be rectangular channels.
The channels can be triangular channels.
In some embodiments, a spacer layer for use in a wound dressing is provided. The spacer layer can comprise a first nonwoven fabric layer comprising a first fibrous base layer and an interconnected first fibrous face layer, wherein a plurality of channels are disposed between the first fibrous base layer and the first fibrous face layer, and a second nonwoven fabric layer comprising a second fibrous base layer and an interconnected second fibrous face layer, wherein a plurality of channels are disposed between the second fibrous base layer and the second fibrous face layer, wherein the second nonwoven fabric layer is disposed over the first nonwoven fabric layer such that the second face layer of the second nonwoven fabric is positioned over the first face layer of the first nonwoven fabric. The spacer layer of this paragraph can include any of the combination of the features described in the preceding paragraphs, among others described herein. Each of the features described in the preceding paragraphs may also be part of another embodiment that does not necessarily include all of the features of this paragraph.
In some embodiments, a method for the treatment of a wound, can comprise providing a wound dressing comprising a spacer layer comprising, a first nonwoven fabric layer comprising a first fibrous base layer and an interconnected first fibrous face layer, wherein a plurality of channels are disposed between the first fibrous base layer and the first fibrous face layer, and a second nonwoven fabric layer comprising a second fibrous base layer and an interconnected second fibrous face layer, wherein a plurality of channels are disposed between the second fibrous base layer and the second fibrous face layer, wherein the second nonwoven fabric layer is disposed over the first nonwoven fabric layer such that the second face layer of the second nonwoven fabric is positioned over the first face layer of the first nonwoven fabric, a cover layer positioned over the spacer layer and comprising an orifice; positioning the dressing over a wound site to form a sealed cavity over the wound site; and applying negative pressure to the wound site through the orifice to draw fluid through the spacer layer into the absorbent layer.
The method of the preceding paragraph may also include any combination of the features described in the following paragraphs, among others described herein. Each of the features described in the following paragraphs may also be part of another embodiment that does not necessarily include all of the features of the previous paragraph.
The wound dressing can further comprise an absorbent layer for absorbing wound exudate, the absorbent layer positioned over the spacer layer.
In some embodiments, a wound treatment apparatus can comprise a wound dressing. The wound dressing can comprise a spacer layer comprising at least one nonwoven fabric layer formed into a three dimensional nonwoven structure, wherein the three dimensional nonwoven structure is formed by thermoforming, chemical bonding, or vacuum forming; a cover layer positioned over the spacer layer.
The apparatus of the preceding paragraph may also include any combination of the features described in the following paragraphs, among others described herein. Each of the features described in the following paragraphs may also be part of another embodiment that does not necessarily include all of the features of the previous paragraph.
The three dimensional nonwoven structure can be formed by thermoforming.
The three dimensional nonwoven structure can be formed by chemical bonding.
The three dimensional nonwoven structure can be formed by vacuum forming.
The three dimensional nonwoven structure can comprise a corrugated structure.
The three dimensional nonwoven structure can comprise a honeycomb structure.
The three dimensional nonwoven structure can comprise a cuboid structure.
The three dimensional nonwoven structure can comprise an egg-box structure.
The three dimensional nonwoven structure can comprise a three dimensional zig-zag structure.
The spacer layer further can comprise one or more support layers, wherein the one or more support layers is positioned over the three dimensional nonwoven structure.
The spacer layer further can comprise one or more support layers, wherein the one or more support layers is positioned below the three dimensional nonwoven structure.
The three dimensional nonwoven structure can comprise a thermoformed nonwoven layer.
The three dimensional nonwoven structure can comprise thermoplastic fibers.
The three dimensional nonwoven structure can comprise a blend of thermoplastic fibers and other fibers.
The other fibers can comprise viscose fibers, gellable fibers, binder fibers, and/or bicomponent fibers.
The three dimensional nonwoven structure can consist essentially of thermoplastic fibers.
The at least one three dimensional nonwoven structure can have a thickness of 2 to 10 mm.
The at least one three dimensional nonwoven structure can have a thickness of about 3 mm.
The nonwoven fabric can be produced by airlaying, carding, or meltspinning
The nonwoven fabric can be isotropic.
The nonwoven fabric can comprise polypropylene.
The nonwoven fabric can be hydroentangled.
The wound dressing can further comprise an absorbent layer for absorbing wound exudate, the absorbent layer positioned over the spacer layer.
The wound dressing can further comprise a second spacer layer positioned over the absorbent layer.
The spacer layer can further comprise a first thermoformed nonwoven fabric layer and a second thermoformed fabric layer disposed over the first thermoformed nonwoven fabric layer.
The spacer layer can further comprise a three dimensional knitted or fabric layer.
The wound treatment apparatus can further comprise a pump, a suction port for applying negative pressure to a wound site through the orifice in the cover layer.
In some embodiments, a spacer layer for use in a wound dressing is provided. The spacer layer can comprise at least one thermoformed nonwoven fabric layer comprising a three dimensional structure, wherein the thermoformed nonwoven fabric comprises thermoplastic fibers. The spacer layer of this paragraph can include any of the combination of the features described in the preceding paragraphs, among others described herein. Each of the features described in the preceding paragraphs may also be part of another embodiment that does not necessarily include all of the features of this paragraph.
A method for the treatment of a wound can comprise positioning a dressing over a wound site to form a sealed cavity over the wound site, the dressing comprising a spacer layer comprising at least one nonwoven fabric layer formed into a three dimensional nonwoven structure, and a cover layer overlying the spacer layer; and applying negative pressure to the wound site to draw fluid through the spacer layer.
The method of the preceding paragraph may also include any combination of the features described in the following paragraphs, among others described herein. Each of the features described in the following paragraphs may also be part of another embodiment that does not necessarily include all of the features of the previous paragraph.
The dressing can further comprise an absorbent layer for absorbing wound exudate, the absorbent layer positioned over the spacer layer.
The cover layer can comprise an orifice and negative pressure is applied to the wound site through the orifice.
Any of the features, components, or details of any of the arrangements or embodiments disclosed in this application, including without limitation any of the dressing embodiments, pump embodiments, and any of the negative pressure wound therapy embodiments disclosed below, are interchangeably combinable with any other features, components, or details of any of the arrangements or embodiments disclosed herein to form new arrangements and embodiments.
Embodiments of the present disclosure will now be described hereinafter, by way of example only, with reference to the accompanying drawings in which:
The disclosed technology relates to the wound dressing disclosed herein, and to methods and uses disclosed herein.
At least some embodiments of the disclosed technology disclosed herein are described below.
Embodiments disclosed herein relate to apparatuses and methods of treating a wound with or without reduced pressure, including optionally a source of negative pressure and wound dressing components and apparatuses. The apparatuses and components comprising the wound overlay and packing materials, if any, are sometimes collectively referred to herein as dressings. In some embodiments, the wound dressing can be provided to be utilized without reduced pressure.
Preferred embodiments disclosed herein relate to wound therapy for a human or animal body. Therefore, any reference to a wound herein can refer to a wound on a human or animal body, and any reference to a body herein can refer to a human or animal body. The term “wound” as used herein, in addition to having its broad ordinary meaning, includes any body part of a patient that may be treated using negative pressure. It is to be understood that the term wound is to be broadly construed and encompasses open and closed wounds in which skin is torn, cut or punctured or where trauma causes a contusion, or any other superficial or other conditions or imperfections on the skin of a patient or otherwise that benefit from reduced pressure treatment. A wound is thus broadly defined as any damaged region of tissue where fluid may or may not be produced. Examples of such wounds include, but are not limited to, abdominal wounds or other large or incisional wounds, either as a result of surgery, trauma, sterniotomies, fasciotomies, or other conditions, dehisced wounds, acute wounds, chronic wounds, subacute and dehisced wounds, traumatic wounds, flaps and skin grafts, lacerations, abrasions, contusions, bums, diabetic ulcers, pressure ulcers, stoma, surgical wounds, trauma and venous ulcers or the like.
As used herein a chronic wound is one that does not heal in an orderly set of stages and in a predictable amount of time the way most wounds do; wounds that do not heal within three months are often considered chronic. For example a chronic wound may include an ulcer such as a diabetic ulcer, a pressure ulcer (or pressure injury), or venous ulcer.
Treatment of such wounds can be performed using negative pressure wound therapy, wherein a reduced or negative pressure can be applied to the wound to facilitate and promote healing of the wound. It will also be appreciated that the wound dressing and methods as disclosed herein may be applied to other parts of the body, and are not necessarily limited to treatment of wounds.
It will be understood that embodiments of the present disclosure are generally applicable to use in topical negative pressure (“TNP”) therapy systems. Briefly, negative pressure wound therapy assists in the closure and healing of many forms of “hard to heal” wounds by reducing tissue oedema; encouraging blood flow and granular tissue formation; removing excess exudate and may reduce bacterial load (and thus infection risk). In addition, the therapy allows for less disturbance of a wound leading to more rapid healing. TNP therapy systems may also assist in the healing of surgically closed wounds by removing fluid and by helping to stabilize the tissue in the apposed position of closure. A further beneficial use of TNP therapy can be found in grafts and flaps where removal of excess fluid is important and close proximity of the graft to tissue is required in order to ensure tissue viability.
As is used herein, reduced or negative pressure levels, such as −X mmHg, represent pressure levels relative to normal ambient atmospheric pressure, which can correspond to 760 mmHg (or 1 atm, 29.93 inHg, 101.325 kPa, 14.696 psi, etc.). Accordingly, a negative pressure value of −X mmHg reflects absolute pressure that is X mmHg below 760 mmHg or, in other words, an absolute pressure of (760−X) mmHg In addition, negative pressure that is “less” or “smaller” than X mmHg corresponds to pressure that is closer to atmospheric pressure (e.g., −40 mmHg is less than −60 mmHg). Negative pressure that is “more” or “greater” than −X mmHg corresponds to pressure that is further from atmospheric pressure (e.g., −80 mmHg is more than −60 mmHg). In some embodiments, local ambient atmospheric pressure is used as a reference point, and such local atmospheric pressure may not necessarily be, for example, 760 mmHg
The negative pressure range for some embodiments of the present disclosure can be approximately −80 mmHg, or between about −20 mmHg and −200 mmHg Note that these pressures are relative to normal ambient atmospheric pressure, which can be 760 mmHg. Thus, −200 mmHg would be about 560 mmHg in practical terms. In some embodiments, the pressure range can be between about −40 mmHg and −150 mmHg Alternatively a pressure range of up to −75 mmHg, up to −80 mmHg or over −80 mmHg can be used. Also in other embodiments a pressure range of below −75 mmHg can be used. Alternatively, a pressure range of over approximately −100 mmHg, or even −150 mmHg, can be supplied by the negative pressure apparatus.
In some embodiments of wound closure devices described herein, increased wound contraction can lead to increased tissue expansion in the surrounding wound tissue. This effect may be increased by varying the force applied to the tissue, for example by varying the negative pressure applied to the wound over time, possibly in conjunction with increased tensile forces applied to the wound via embodiments of the wound closure devices. In some embodiments, negative pressure may be varied over time for example using a sinusoidal wave, square wave, or in synchronization with one or more patient physiological indices (e.g., heartbeat). Examples of such applications where additional disclosure relating to the preceding may be found include U.S. Pat. No. 8,235,955, titled “Wound treatment apparatus and method,” issued on Aug. 7, 2012; and U.S. Pat. No. 7,753,894, titled “Wound cleansing apparatus with stress,” issued Jul. 13, 2010. The disclosures of both of these patents are hereby incorporated by reference in their entireties.
Embodiments of the wound dressings, wound dressing components, wound treatment apparatuses and methods described herein may also be used in combination or in addition to those described in International Application No. PCT/IB2013/001469, filed May 22, 2013, published as WO 2013/175306 A2 on Nov. 28, 2013, titled “APPARATUSES AND METHODS FOR NEGATIVE PRESSURE WOUND THERAPY,” International Application No. PCT/IB2013/002060, filed on Jul. 31, 2013 published as WO2014/020440, entitled “WOUND DRESSING,” the disclosures of which are hereby incorporated by reference in their entireties. Embodiments of the wound dressings, wound treatment apparatuses and methods described herein may also be used in combination or in addition to those described in U.S. patent application Ser. No. 13/092,042, filed Apr. 21 2011, U.S. Pat. No. 9,061,095, titled “WOUND DRESSING AND METHOD OF USE,” and U.S. patent application Ser. No. 14/715,527, filed May 18, 2015, titled “FLUIDIC CONNECTOR FOR NEGATIVE PRESSURE WOUND THERAPY,” the disclosures of which are hereby incorporated by reference in their entireties, including further details relating to embodiments of wound dressings, the wound dressing components and principles, and the materials used for the wound dressings.
Additionally, some embodiments related to TNP wound treatment comprising a wound dressing in combination with a pump or associated electronics described herein may also be used in combination or in addition to those described in International Patent Application No. PCT/EP2016/059329, filed on Apr. 26, 2016, entitled “REDUCED PRESSURE APPARATUSES,” published as WO 2016/174048, on Nov. 3, 2016, the entirety of which is hereby incorporated by reference. In some of these embodiments, the pump or associate electronic components may be integrated into the wound dressing to provide a single article to be applied to the wound.
The channels or apertures created in the nonwoven material can be utilized for the structure they provide in the material. The fiber choice and bonding level can be engineered to provide rigidity and desirable compression/recovery performance. In some embodiments, the nonwoven fabric layer can be a blend of polyester and bio component fiber to produce a rigid blend. In some embodiments, the nonwoven fabric layer can include fiber blends or synthetic or cellulosic fibers, including thermoplastic and bi-component fibers. In some embodiments, the nonwoven fabric layer can be engineered with a hydrophilic fabric face and a hydrophobic fabric back or base utilizing web placement and different fiber mixes. In other embodiments, the fabric face can be hydrophobic and the fabric back or base can be hydrophilic.
As shown in
In some embodiments, two layers of this structure can be inverted onto one another to create a spacer type layer as shown in
In some embodiments, the layer formed from the two nonwoven fabric layers can have the performance benefits of a 3D spacer fabric or other spacer fabric described herein in terms of compression under loading and compression recovery. For example, in some embodiments, the spacer layer formed from the nonwoven fabric layers as described herein can remain open upon application of negative pressure to the layer and/or a wound dressing. In some embodiments, the apertures, channels, and/or slits of the nonwoven fabric layer can allow for unique fluid management properties.
In some embodiments, the channels of the first or second nonwoven fabric layers extend across an entire length of the first and second nonwoven fabric layers. The channels of the first nonwoven fabric layer extend in a first direction and the channels of the second nonwoven fabric layer extend in a second direction. In some embodiments, the channels of the first nonwoven fabric layer can be parallel to the channels of the second nonwoven fabric layer. In other embodiments, the channels of the first nonwoven fabric layer can be perpendicular to the channels of the second nonwoven fabric layer. In such an embodiment, the spacer layer would be different from that shown in
In some embodiments, the three dimensional nonwoven spacer layer 12 can be used as a spacer or transmission layer in a wound dressing as described herein. In some embodiments, the three dimensional nonwoven material constructions as described herein can provide a high level of compression recovery and a unique compression under loading characteristic which may not be currently available in traditional nonwoven constructions. These properties can allow for the three dimensional nonwoven spacer layer to be used in a wound dressing and allow transmission of fluids through the open channels in the spacer layer even while the dressing is compressed.
In some embodiments, a typical nonwoven fabric can be constructed into a three dimensional (3D) structure. The three dimensional structure can be an egg-box type construction as illustrated in
In some embodiments, heat and pressure can be used to set the nonwoven into a 3D structure such as in a corrugated construction, a three dimensional zig-zag pattern, an egg-box type construction, a checkerboard construction, and a hexagonal (honeycomb) construction. The three dimensional zig zag construction can be similar to the corrugated construction but instead of corrugated lines a shape such as a zig zag can allow for 2-way conformability. The fiber based media of the nonwoven material can enable compression recovery properties of a spacer layer.
In some embodiments, the nonwoven material can be thermoformed into the three dimensional construction. In other embodiments, the three dimensional nonwoven material can be formed using a chemical bonding and vacuum forming.
In some embodiments, the three dimensional nonwoven spacer layer can consist of two or three layers of polypropylene based hydroentangled nonwoven molded into an egg-box style pattern to about 2-10 mm thickness each. In some embodiments, the three dimensional nonwoven spacer layer can consist of two or three layers of polypropylene based hydroentangled nonwoven molded into an egg-box style pattern to less than 2 mm, about 2-3 mm, about 3-4 mm, about 4-5 mm, about 5-6 mm, about 6-7 mm, about 7-8 mm, about 8-9 mm, about 9-10 mm, and/or greater than 10 mm thickness each. In some embodiments, the three dimensional nonwoven spacer layer can consist of two or three layers of polypropylene based hydroentangled nonwoven molded into an egg-box style pattern to around 3mm thickness each. The nonwoven can be either 100% thermoplastic fiber content or a blend of thermoplastic fibers and other fibers such as viscose or gellable fibers. In some embodiments, the nonwoven spacer layer may include binder fibers or bicomponent fibers. The nonwoven may be produced by traditional nonwoven technologies such as airlaying, carding, or meltspinning. In some embodiments, isotropic nonwovens may also be used. In some embodiments, the nonwoven can be nonisotropic. In some embodiments, the three dimensional nonwoven material can use shape memory polymers.
In some embodiments, the three dimensional construction can be layered with other nonwovens and/or multiple layers of three dimensional nonwoven layers to form the spacer layer.
In some embodiments, the spacer layer can include a first three dimensional nonwoven spacer layer and a second three dimensional nonwoven spacer layer. The first three dimensional nonwoven spacer layer can be disposed over the second three dimensional nonwoven spacer layer. The first and second three dimensional nonwoven spacer layer can be a thermoformed nonwoven fabric layer.
In some embodiments, the one or more layers of apertured nonwoven layers, similar to the aperture nonwoven layers described with reference to
In some embodiments, the constructed three dimensional nonwoven, similar to the three dimensional nonwoven spacer layers described with reference to
In some embodiments, the absorbent layer can comprise a nonwoven containing superabsorbent particles or fibers. In some embodiments, the top film or backing layer can be a moisture vapor permeable material. In some embodiments, the dressing can include a masking layer positioned below the top film or backing layer. In some embodiments, the absorbent layer can overly and directly contact the spacer layer.
The wound dressing may be suitable to include within a negative pressure wound apparatus.
The wound dressing may be suitable to include within a non-negative pressure wound apparatus.
The dressing is designed to be easy to apply and may be removed in one piece.
In one embodiment the dressing does not require secondary retention.
The wound dressing may be wrapped and sterile.
The wound dressing may be a negative pressure wound dressing, or a non-negative pressure wound dressing.
The disclosed technology in one embodiment relates to a non-negative pressure wound therapy kit comprising the wound dressing.
The wound dressing may be used as the dressing component of a negative pressure wound dressing apparatus. The apparatus in different embodiments comprises a canister and is free of the canister.
In one embodiment the disclosed technology relates to a negative pressure wound therapy kit comprising a wound dressing outlined above and a negative pressure source configured to be fluidically connected to the wound dressing.
In one embodiment the disclosed technology relates to a method of providing negative pressure wound therapy to a wound, the method comprising:
placing the wound dressing outlined above over a wound;
forming a fluid flow path between the wound dressing and a negative pressure source; and
operating the negative pressure source to provide negative pressure to the wound.
In one embodiment the disclosed technology relates to a method of operating a negative pressure wound system, the method comprising:
operating a negative pressure source fluidically connected to a wound dressing outlined above, the wound dressing configured to be positioned over a wound.
The wound dressing may be used as wound dressing for a non-negative pressure wound dressing apparatus.
In one embodiment the disclosed technology relates to a method of placing the wound dressing disclosed herein comprising an absorbent layer, wherein the wound dressing configured to be positioned over a wound, and exudate may be removed by evaporating exudate through an absorbent layer.
The wound dressing disclosed herein may be placed over a wound for 1 to 10 days, typically 3-7 days. The wound dressing may be replaced either when the wound is in the opinion of the HCP sufficiently healed, and/or when any absorbent layer/canister is saturated/full. The wound dressing can be replaced and/or canister can be replaced leaving the original dressing in place.
In one embodiment the non-negative pressure wound therapy kit comprises or consists of:
a wound dressing disclosed herein; and
a dressing fixative (may also be defined as a secondary retention).
The dressing fixative may be securing means that can include adhesive (e.g. with pressure-sensitive adhesive) and non-adhesive, and elastic and non-elastic straps, bands, loops, strips, ties, bandages, e.g. compression bandages, sheets, covers, sleeves, jackets, sheathes, wraps, stockings and hose, e.g. elastic tubular hose or elastic tubular stockings that are a compressive fit over a limb wound to apply suitable pressure to it when the therapy is applied in this way; and inflatable cuffs, sleeves, jackets, trousers, sheathes, wraps, stockings and hose that are a compressive fit over a limb wound to apply suitable pressure to it when the therapy is applied in this way.
Such securing means may each be laid out over the wound dressing to extend beyond the periphery of the backing layer of the wound dressing, and as appropriate will be adhered or otherwise secured to the skin around the wound and/or itself and as appropriate will apply compression (e.g. with elastic bandages, stockings) to a degree that is sufficient to hold the wound dressing in place in a fluid-tight seal around the periphery of the wound.
Such securing means may each be integral with the other components of the dressing, in particular the backing layer.
Alternatively, it may be permanently attached or releasably attached to the dressing, in particular the backing layer, with an adhesive film, for example, or these components may be a Velcro™, push snap or twist-lock fit with each other.
The securing means and the dressing may be separate structures, permanently unattached to each other.
In one embodiment the dressing fixative may include a bandage, tubular or compression bandage, tape, gauze, or backing layer.
In one embodiment the disclosed technology relates to a non-negative pressure method of providing wound therapy to a wound, the method comprising: placing the wound dressing disclosed herein over a wound; and securing the wound dressing with a dressing fixative such as a bandage, tape, gauze, or backing layer.
In one embodiment the wound dressing further comprises a backing layer.
The backing layer may be transparent or opaque film The transparent backing layer (may be referred to as top layer or top film) may provide the healthcare professional (HCP) with the ability to carry out regular assessments of the wound site including the peri-wound area and the wound itself without the need to lift or remove the dressing. This may allow the HCP to react early to signs that could potentially delay the healing process. Encouraging healing and reducing the chance of infection can lead to shorter recovery times and lower treatment costs.
The material used to form the transparent backing layer may have a high Moisture Vapor Transmission Rate (MVTR), thereby allowing unwanted moisture to transpire and helps prevent infection and maceration.
The transparent backing layer may be waterproof, thereby enabling the patient to shower/bathe with the dressing in situ.
The transparent backing layer may provide a bather against bacteria, including methicillin-resistant staphylococcus aureus (MRSA). This will reduce the incidences of surgical site infections (SSI) and healthcare associated infections (HAI), reducing possible associated costs to healthcare provider and extended hospital stay for the patient.
The transparent backing layer may further act as a bather to water and dirt.
The backing layer may be a film In one embodiment the backing layer is a polyurethane film The polyurethane film may be optionally functionalized with additives such as antimicrobial agents, odor control, pigments, dyes or UV disruptors. The backing layer may be a monolithic or microporous film or a foam. It may also be an impermeable film
In one embodiment the wound dressing does not further comprise a backing layer.
In one embodiment the wound dressing further comprises an adhesive layer.
The adhesive layer may be located:
The adhesive may be a silicone adhesive or an acrylic adhesive.
The adhesive may be spread evenly across the surfaces of the first and second layer of the disclosed technology. An even spread of adhesive may ensure that the surfaces of the layers of the disclosed technology are securely joined.
If the adhesive layer is on the underside of the backing layer it provides adhesion to the wound dressing to a peri-wound area.
Alternatively, the adhesive can be spread in a pattern to increase breathability of the film and improve comfort upon removal.
The adhesive used may be low allergy. This type of adhesive reduces the trauma upon removal of the dressings and/or lessens the risk of an allergic reaction.
In one embodiment the wound dressing may include a number of layers that are built up in a generally laminar fashion to form a dressing having a relatively planar form. Examples of such a wound dressing may for instance be disclosed in WO2013/007793.
In one embodiment the wound dressing may include a border region extending around the outer periphery of the dressing and a raised central region (or pouch) in the center of the dressing (in plain view). The precise dimensions of the border region and the central region may be predetermined to suit a particular wound or particular wound type.
Alternatively in another embodiment there may be no border region required. Here the border region has the general function of providing an area for sealingly engaging with a patient's skin surrounding a wound site to form a sealed cavity over the wound site. The central region is the location of further functional elements of the wound dressing.
The wound dressing disclosed herein may include a perforated wound contact layer and a top film Further components of the wound dressing optionally include in no particular order:
In separate embodiments the wound dressing comprises two, three, or all of the layers disclosed above.
In one embodiment the wound dressing comprises all of the layers disclosed above in the order of a layer of polyurethane hydrocellular foam to the three-dimensional knitted spacer fabric in the specified order.
Alternatively the wound contact layer may be formed from any suitable polymer, e.g. silicone, ethylvinyl acetate, polyethylene, polypropylene, or polyester, or a combination thereof. The skin-compatible adhesive is coated on the lower side of the layer, i.e. the side that is to contact the patient. Aptly the adhesive is coated as a continuous layer on the underside of the layer. The adhesive may be coated in a semi-continuous layer such as in a pattern such as a checkerboard pattern, polka dot pattern, herring bone pattern, mesh pattern or other suitable pattern.
As shown in
As used herein the upper layer, top layer, or layer above refers to a layer furthest from the surface of the skin or wound while the dressing is in use and positioned over the wound. Accordingly, the lower surface, lower layer, bottom layer, or layer below refers to the layer that is closest to the surface of the skin or wound while the dressing is in use and positioned over the wound.
As illustrated in
Some embodiments of the wound contact layer 222 may also act as a carrier for an optional lower and upper adhesive layer (not shown). For example, a lower pressure sensitive adhesive may be provided on the lower surface 224 of the wound dressing 100 whilst an upper pressure sensitive adhesive layer may be provided on the upper surface 223 of the wound contact layer. The pressure sensitive adhesive, which may be a silicone, hot melt, hydrocolloid or acrylic based adhesive or other such adhesives, may be formed on both sides or optionally on a selected one or none of the sides of the wound contact layer. When a lower pressure sensitive adhesive layer is utilized may be helpful to adhere the wound dressing 100 to the skin around a wound site. In some embodiments, the wound contact layer may comprise perforated polyurethane film The lower surface of the film may be provided with a silicone pressure sensitive adhesive and the upper surface may be provided with an acrylic pressure sensitive adhesive, which may help the dressing maintain its integrity. In some embodiments, a polyurethane film layer may be provided with an adhesive layer on both its upper surface and lower surface, and all three layers may be perforated together.
A transmission layer 226 can be located above the wound contact layer 222. In some embodiments, the transmission layer can be a porous material. As used herein the transmission layer can be referred to as a spacer layer and the terms can be used interchangeably to refer to the same component described herein. This transmission layer 226 allows transmission of fluid including liquid and gas away from a wound site into upper layers of the wound dressing. In particular, the transmission layer 226 preferably ensures that an open air channel can be maintained to communicate negative pressure over the wound area even when the absorbent layer has absorbed substantial amounts of exudates. The layer 226 should preferably remain open under the typical pressures that will be applied during negative pressure wound therapy as described above, so that the whole wound site sees an equalized negative pressure. The layer 226 may be formed of a material having a three dimensional structure. For example, a knitted or woven spacer fabric (for example Baltex 7970 weft knitted polyester) or a non-woven fabric could be used. The three dimensional material can comprise a 3D spacer fabric material similar to the material described in International Application WO 2013/175306 A2 and International Application WO2014/020440, the disclosures of which are incorporated by reference in their entireties.
In some embodiments, the layer 226 can comprise an apertured nonwoven fabric spacer layer formed from the two layers of nonwoven fabric as described previously herein and illustrated in
In some embodiments, the plurality apertures of the nonwoven fabric layer can form a channel. The channels or apertures created in the nonwoven material can be utilized for the structure they provide in the material. For example, in some embodiments, the spacer layer formed from the nonwoven fabric layers as described herein can remain open upon application of negative pressure to the layer and/or a wound dressing. In some embodiments, the apertures, channels, and/or slits of the nonwoven fabric layer can allow for unique fluid management properties. In some embodiments, the layer formed from the two nonwoven fabric layers can have the performance benefits of a 3D spacer fabric or other spacer fabric described herein in terms of compression under loading and compression recovery. In such embodiments, the apertured nonwoven spacer layer can allow transmission of fluid including liquid and gas away from a wound site into upper layers of the wound dressing.
In some embodiments, the layer 226 can comprise a three dimensional nonwoven spacer layer construction as described previously herein and illustrated in
In some embodiments, the 3D structure can be layered on top of one another or with traditional nonwovens to create a spacer type layer for use in a wound dressing.
For example, in some embodiments, the spacer layer formed from the nonwoven layers as described herein can remain open upon compression and/or application of negative pressure to the layer and/or a wound dressing. In some embodiments, the three dimensional structure of the nonwoven spacer layer can allow for unique fluid management properties. In some embodiments, the three dimensional nonwoven spacer layer formed from the nonwoven fabric layers can have the performance benefits of a 3D spacer fabric or other spacer fabric described herein in terms of compression under loading and compression recovery. In such embodiments, the three dimensional nonwoven spacer layer can allow transmission of fluid including liquid and gas away from a wound site into upper layers of the wound dressing.
In some embodiments, a layer 221 of absorbent material is provided above the transmission layer 226. The absorbent material, which can comprise a foam or non-woven natural or synthetic material, and which may optionally comprise a super-absorbent material, forms a reservoir for fluid, particularly liquid, removed from the wound site. In some embodiments, the layer 221 may also aid in drawing fluids towards the backing layer 220.
The material of the absorbent layer 221 may also prevent liquid collected in the wound dressing 100 from flowing freely within the dressing, and preferably acts so as to contain any liquid collected within the dressing. The absorbent layer 221 also helps distribute fluid throughout the layer via a wicking action so that fluid is drawn from the wound site and stored throughout the absorbent layer. This helps prevent agglomeration in areas of the absorbent layer. The capacity of the absorbent material must be sufficient to manage the exudates flow rate of a wound when negative pressure is applied. Since in use the absorbent layer experiences negative pressures the material of the absorbent layer is chosen to absorb liquid under such circumstances. A number of materials exist that are able to absorb liquid when under negative pressure, for example superabsorber material. The absorbent layer 221 may typically be manufactured from ALLEVYN™ foam, Freudenberg 114-224-4 or Chem-Posit™11C-450. In some embodiments, the absorbent layer 221 may comprise a composite comprising superabsorbent powder, fibrous material such as cellulose, and bonding fibers. In a preferred embodiment, the composite is an airlaid, thermally-bonded composite.
In some embodiments, the absorbent layer 221 is a layer of non-woven cellulose fibers having super-absorbent material in the form of dry particles dispersed throughout. Use of the cellulose fibers introduces fast wicking elements which help quickly and evenly distribute liquid taken up by the dressing. The juxtaposition of multiple strand-like fibers leads to strong capillary action in the fibrous pad which helps distribute liquid. In this way, the super-absorbent material is efficiently supplied with liquid. The wicking action also assists in bringing liquid into contact with the upper cover layer to aid increase transpiration rates of the dressing.
An aperture, hole, or orifice 227 is preferably provided in the backing layer 220 to allow a negative pressure to be applied to the dressing 100. The fluidic connector 110 is preferably attached or sealed to the top of the backing layer 220 over the orifice 227 made into the dressing 100, and communicates negative pressure through the orifice 227. A length of tubing may be coupled at a first end to the fluidic connector 110 and at a second end to a pump unit (not shown) to allow fluids to be pumped out of the dressing. Where the fluidic connector is adhered to the top layer of the wound dressing, a length of tubing may be coupled at a first end of the fluidic connector such that the tubing, or conduit, extends away from the fluidic connector parallel or substantially to the top surface of the dressing. The fluidic connector 110 may be adhered and sealed to the backing layer 220 using an adhesive such as an acrylic, cyanoacrylate, epoxy, UV curable or hot melt adhesive. The fluidic connector 110 may be formed from a soft polymer, for example a polyethylene, a polyvinyl chloride, a silicone or polyurethane having a hardness of 30 to 90 on the Shore A scale. In some embodiments, the fluidic connector 110 may be made from a soft or conformable material.
Optionally, the absorbent layer 221 includes at least one through hole 228 located so as to underlie the fluidic connector 110. The through hole 228 may in some embodiments be the same size as the opening 227 in the backing layer, or may be bigger or smaller. As illustrated in
The aperture or through-hole 228 is preferably provided in the absorbent layer 221 beneath the orifice 227 such that the orifice is connected directly to the transmission layer 226 as illustrated in
The backing layer 220 is preferably gas impermeable, but moisture vapor permeable, and can extend across the width of the wound dressing 100. The backing layer 220, which may for example be a polyurethane film (for example, Elastollan SP9109) having a pressure sensitive adhesive on one side, is impermeable to gas and this layer thus operates to cover the wound and to seal a wound cavity over which the wound dressing is placed. In this way, an effective chamber is made between the backing layer 220 and a wound site where a negative pressure can be established. The backing layer 220 is preferably sealed to the wound contact layer 222 in a border region around the circumference of the dressing, ensuring that no air is drawn in through the border area, for example via adhesive or welding techniques. The backing layer 220 protects the wound from external bacterial contamination (bacterial bather) and allows liquid from wound exudates to be transferred through the layer and evaporated from the film outer surface. The backing layer 220 preferably comprises two layers; a polyurethane film and an adhesive pattern spread onto the film. The polyurethane film is preferably moisture vapor permeable and may be manufactured from a material that has an increased water transmission rate when wet. In some embodiments, the moisture vapor permeability of the backing layer increases when the backing layer becomes wet. The moisture vapor permeability of the wet backing layer may be up to about ten times more than the moisture vapor permeability of the dry backing layer.
The absorbent layer 221 may be of a greater area than the transmission layer 226, such that the absorbent layer overlaps the edges of the transmission layer 226, thereby ensuring that the transmission layer does not contact the backing layer 220. This provides an outer channel of the absorbent layer 221 that is in direct contact with the wound contact layer 222, which aids more rapid absorption of exudates to the absorbent layer. Furthermore, this outer channel ensures that no liquid is able to pool around the circumference of the wound cavity, which may otherwise seep through the seal around the perimeter of the dressing leading to the formation of leaks. As illustrated in
As shown in
In particular for embodiments with a single fluidic connector 110 and through hole, it may be preferable for the fluidic connector 110 and through hole to be located in an off-center position as illustrated in
Turning now to the fluidic connector 110, preferred embodiments comprise a sealing surface 216, a bridge 211 (corresponding to bridge 120 in
Some embodiments may further comprise an optional second fluid passage positioned above the first fluid passage 212. For example, some embodiments may provide for an air leak may be disposed at the proximal end of the top layer that is configured to provide an air path into the first fluid passage 212 and dressing 100 similar to the suction adapter as described in U.S. application Ser. No. 13/381,885, filed Dec. 20, 2011, entitled “APPARATUSES AND METHODS FOR NEGATIVE PRESSURE WOUND THERAPY,” and patented as U.S. Pat. No. 8,801,685, which is incorporated by reference herein in its entirety.
Preferably, the fluid passage 212 is constructed from a compliant material that is flexible and that also permits fluid to pass through it if the spacer is kinked or folded over. Suitable materials for the fluid passage 212 include without limitation foams, including open-cell foams such as polyethylene or polyurethane foam, meshes, 3D knitted fabrics, apertured nonwoven fabric spacer layer as described herein with reference to
In some embodiments, the fluid passage 212 may be comprised of a wicking fabric, for example apertured nonwoven fabric spacer layer as described herein with reference to
Preferably, the filter element 214 is impermeable to liquids, but permeable to gases, and is provided to act as a liquid barrier and to ensure that no liquids are able to escape from the wound dressing 100. The filter element 214 may also function as a bacterial barrier. Typically the pore size is 0.2 μm. Suitable materials for the filter material of the filter element 214 include 0.2 micron Gore™ expanded PTFE from the MMT range, PALL Versapore™ 200R, and Donaldson™ TX6628. Larger pore sizes can also be used but these may require a secondary filter layer to ensure full bioburden containment. As wound fluid contains lipids it is preferable, though not essential, to use an oleophobic filter membrane for example 1.0 micron MMT-332 prior to 0.2 micron MMT-323. This prevents the lipids from blocking the hydrophobic filter. The filter element can be attached or sealed to the port or the cover film over the orifice. For example, the filter element 214 may be molded into the fluidic connector 110, or may be adhered to one or both of the top of the cover layer and bottom of the suction adapter 110 using an adhesive such as, but not limited to, a UV cured adhesive.
It will be understood that other types of material could be used for the filter element 214. More generally a microporous membrane can be used which is a thin, flat sheet of polymeric material, this contains billions of microscopic pores. Depending upon the membrane chosen these pores can range in size from 0.01 to more than 10 micrometers. Microporous membranes are available in both hydrophilic (water filtering) and hydrophobic (water repellent) forms. In some embodiments, filter element 214 comprises a support layer and an acrylic co-polymer membrane formed on the support layer. Preferably the wound dressing 100 according to certain embodiments uses microporous hydrophobic membranes (MHMs). Numerous polymers may be employed to form MHMs. For example, the MHMs may be formed from one or more of PTFE, polypropylene, PVDF and acrylic copolymer. All of these optional polymers can be treated in order to obtain specific surface characteristics that can be both hydrophobic and oleophobic. As such these will repel liquids with low surface tensions such as multi-vitamin infusions, lipids, surfactants, oils and organic solvents.
MHMs block liquids whilst allowing air to flow through the membranes. They are also highly efficient air filters eliminating potentially infectious aerosols and particles. A single piece of MHM is well known as an option to replace mechanical valves or vents. Incorporation of MHMs can thus reduce product assembly costs improving profits and costs/benefit ratio to a patient.
The filter element 214 may also include an odor absorbent material, for example activated charcoal, carbon fiber cloth or Vitec Carbotec-RT Q2003073 foam, or the like. For example, an odor absorbent material may form a layer of the filter element 214 or may be sandwiched between microporous hydrophobic membranes within the filter element. The filter element 214 thus enables gas to be exhausted through the orifice. Liquid, particulates and pathogens however are contained in the dressing.
Similar to the embodiments of wound dressings described above, some wound dressings comprise a perforated wound contact layer with silicone adhesive on the skin-contact face and acrylic adhesive on the reverse. Above this bordered layer sits a transmission layer. Above the transmission layer, sits an absorbent layer. The absorbent layer can include a superabsorbent non-woven (NW) pad. The absorbent layer can over-border the transmission layer by approximately 5 mm at the perimeter. The absorbent layer can have an aperture or through-hole toward one end. The aperture can be about 10 mm in diameter. Over the transmission layer and absorbent layer lies a backing layer. The backing layer can be a high moisture vapor transmission rate (MVTR) film, pattern coated with acrylic adhesive. The high MVTR film and wound contact layer encapsulate the transmission layer and absorbent layer, creating a perimeter border of approximately 20 mm. The backing layer can have a 10 mm aperture that overlies the aperture in the absorbent layer. Above the hole can be bonded a fluidic connector that comprises a liquid-impermeable, gas-permeable semi-permeable membrane (SPM) or filter that overlies the aforementioned apertures.
In some embodiments, the one or more transmission layers 503 and 504 can comprise an apertured nonwoven fabric spacer layer formed from the two layers of nonwoven fabric as described previously herein and illustrated in
In some embodiments, the plurality apertures of the nonwoven fabric layer can form a channel. The channels or apertures created in the nonwoven material can be utilized for the structure they provide in the material. For example, in some embodiments, the spacer layer formed from the nonwoven fabric layers as described herein can remain open upon application of negative pressure to the layer and/or a wound dressing. In some embodiments, the apertures, channels, and/or slits of the nonwoven fabric layer can allow for unique fluid management properties. In some embodiments, the layer formed from the two nonwoven fabric layers can have the performance benefits of a 3D spacer fabric or other spacer fabric described herein in terms of compression under loading and compression recovery. In such embodiments, the apertured nonwoven spacer layer can allow transmission of fluid including liquid and gas away from a wound site into upper layers of the wound dressing.
In some embodiments, the one or more transmission layers 503 and 504 can comprise a three dimensional nonwoven spacer layer construction as described previously herein and illustrated in
In some embodiments, the 3D structure can be layered on top of one another or with traditional nonwovens to create a spacer type layer for use in a wound dressing.
For example, in some embodiments, the spacer layer formed from the nonwoven layers as described herein can remain open upon compression and/or application of negative pressure to the layer and/or a wound dressing. In some embodiments, the three dimensional structure of the nonwoven spacer layer can allow for unique fluid management properties. In some embodiments, the three dimensional nonwoven spacer layer formed from the nonwoven fabric layers can have the performance benefits of a 3D spacer fabric or other spacer fabric described herein in terms of compression under loading and compression recovery. In such embodiments, the three dimensional nonwoven spacer layer can allow transmission of fluid including liquid and gas away from a wound site into upper layers of the wound dressing.
In some embodiments, additional layers such as another transmission layer or an obscuring layer 503 may be provided over the absorbent layer 503 and beneath the backing layer 501. Additionally, some embodiments related to wound treatment comprising a wound dressing described herein may also be used in combination or in addition to those described in U.S. Application Publication No. 2014/0249495, filed May 21, 2014, entitled “WOUND DRESSING AND METHOD OF TREATMENT” the disclosure of which are hereby incorporated by reference in its entirety, including further details relating to embodiments of wound dressings, the wound dressing components and principles, and the materials used for the wound dressings.
In some embodiments, a source of negative pressure (such as a pump) and some or all other components of the TNP system, such as power source(s), sensor(s), connector(s), user interface component(s) (such as button(s), switch(es), speaker(s), screen(s), etc.) and the like, can be integral with the wound dressing. Additionally, some embodiments related to wound treatment comprising a wound dressing described herein may also be used in combination or in addition to those described in International Application WO 2016/174048 and International Patent Application PCT/EP2017/055225, filed on Mar. 6, 2017, entitled “WOUND TREATMENT APPARATUSES AND METHODS WITH NEGATIVE PRESSURE SOURCE INTEGRATED INTO THE WOUND DRESSING,” the disclosure of which is hereby incorporated by reference in its entirety herein, including further details relating to embodiments of wound dressings, the wound dressing components and principles, and the materials used for the wound dressings and wound dressing components.
In some embodiments, the pump and/or other electronic components can be configured to be positioned adjacent to or next to the absorbent and/or transmission layers in the wound dressing so that the pump and/or other electronic components are still part of a single apparatus to be applied to a patient with the pump and/or other electronics positioned away from the wound site.
The electronics area 1261 can include a source of negative pressure (such as a pump) and some or all other components of the TNP system, such as power source(s), sensor(s), connector(s), user interface component(s) (such as button(s), switch(es), speaker(s), screen(s), etc.) and the like, that can be integral with the wound dressing. For example, the electronics area 1261 can include a button or switch 1211 as shown in
The absorbent area 1260 can include an absorbent material 1212 and can be positioned over the wound site. The electronics area 1261 can be positioned away from the wound site, such as by being located off to the side from the absorbent area 1260. The electronics area 1261 can be positioned adjacent to or next to and in fluid communication with the absorbent area 1260 as shown in
In some embodiments, additional layers of dressing material can be included in the electronics area 1261, the absorbent area 1260, or both areas. In some embodiments, the dressing can comprise one or more spacer or transmission layers and/or one or more absorbent layer positioned above the contact layer and below the wound cover layer 1213 of the dressing.
The dressing can comprise a wound contact layer (not shown), a transmission layer (not shown), an absorbent layer 1212 over the transmission layer, a moisture vapor permeable film or cover layer 1213 positioned above the wound contact layer, transmission layer, absorbent layer, or other layers of the dressing. The wound contact layer can be configured to be in contact with the wound. The wound contact layer can include an adhesive on the patient facing side for securing the dressing to the surrounding skin or on the top side for securing the wound contact layer to a cover layer or other layer of the dressing. In operation, the wound contact layer can be configured to provide unidirectional flow so as to facilitate removal of exudate from the wound while blocking or substantially preventing exudate from returning to the wound. The one or more transmission layers assist in distributing negative pressure over the wound site and facilitating transport of wound exudate and fluids into the wound dressing. In some embodiments, the transmission layer can be formed at least partially from a three dimensional (3D) fabric. Further, an absorbent layer (such as layer 1212) for absorbing and retaining exudate aspirated from the wound can be utilized. In some embodiments, a superabsorbent material can be used in the absorbent layer 1212. In some embodiments, the absorbent includes a shaped form of a superabsorber layer. In some embodiments, the transmission layer can be formed at least partially from an apertured nonwoven fabric spacer layer as described herein with reference to
In some embodiments, the one or more transmission layers can comprise an apertured nonwoven fabric spacer layer formed from the two layers of nonwoven fabric as described previously herein and illustrated in
In some embodiments, the plurality apertures of the nonwoven fabric layer can form a channel. The channels or apertures created in the nonwoven material can be utilized for the structure they provide in the material. For example, in some embodiments, the spacer layer formed from the nonwoven fabric layers as described herein can remain open upon application of negative pressure to the layer and/or a wound dressing. In some embodiments, the apertures, channels, and/or slits of the nonwoven fabric layer can allow for unique fluid management properties. In some embodiments, the layer formed from the two nonwoven fabric layers can have the performance benefits of a 3D spacer fabric or other spacer fabric described herein in terms of compression under loading and compression recovery. In such embodiments, the apertured nonwoven spacer layer can allow transmission of fluid including liquid and gas away from a wound site into upper layers of the wound dressing.
In some embodiments, the one or more transmission layers can comprise a three dimensional nonwoven spacer layer construction as described previously herein and illustrated in
In some embodiments, the 3D structure can be layered on top of one another or with traditional nonwovens to create a spacer type layer for use in a wound dressing.
For example, in some embodiments, the spacer layer formed from the nonwoven layers as described herein can remain open upon compression and/or application of negative pressure to the layer and/or a wound dressing. In some embodiments, the three dimensional structure of the nonwoven spacer layer can allow for unique fluid management properties. In some embodiments, the three dimensional nonwoven spacer layer formed from the nonwoven fabric layers can have the performance benefits of a 3D spacer fabric or other spacer fabric described herein in terms of compression under loading and compression recovery. In such embodiments, the three dimensional nonwoven spacer layer can allow transmission of fluid including liquid and gas away from a wound site into upper layers of the wound dressing.
A cover layer or backing layer 1313 can be positioned over the upper transmission layer. The backing layer 1313 can form a seal to the wound contact layer 1310 at a perimeter region enclosing the transmission layers 1311, 1311′, and 1317, the absorbent layer 1322, layer 1351, and electronic components 1350. In some embodiments, the backing layer 1313 can be a flexible sheet of material that forms and molds around the dressing components when they are applied to the wound. In other embodiments, the backing layer 1313 can be a material that is preformed or premolded to fit around the dressing components as shown in
The dressing 400 may be placed over a wound, and a port 460 (which together with conduit 401 may form a fluidic connector as described with respect to
The cover layer 430, 320, which can be more clearly seen in
The absorbent material 450 as shown in
In some embodiments, the absorbent layer is a layer of non-woven cellulose fibers having super-absorbent material in the form of dry particles dispersed throughout. Use of the cellulose fibers introduces fast wicking elements which help quickly and evenly distribute liquid taken up by the dressing. The juxtaposition of multiple strand-like fibers leads to strong capillary action in the fibrous pad which helps distribute liquid. In this way, the super-absorbent material is efficiently supplied with liquid. Also, all regions of the absorbent layer are provided with liquid.
The wicking action also assists in bringing liquid into contact with the upper cover layer to aid increase transpiration rates of the dressing.
The wicking action also assists in delivering liquid downwards towards the wound bed when exudation slows or halts. This delivery process helps maintain the transmission layer or lower spacer layer and lower wound bed region in a moist state which helps prevent crusting within the dressing (which could lead to blockage) and helps maintain an environment optimized for wound healing.
In some embodiments, the absorbent layer may be an air-laid material. Heat fusible fibers may optionally be used to assist in holding the structure of the pad together. It will be appreciated that rather than using super-absorbing particles or in addition to such use, super-absorbing fibers may be utilized according to certain embodiments of the present invention. An example of a suitable material is the Product Chem-Posite™ 11 C available from Emerging Technologies Inc (ETi) in the USA.
Optionally, according to certain embodiments of the present invention, the absorbent layer may include synthetic stable fibers and/or bi-component stable fibers and/or natural stable fibers and/or super-absorbent fibers. Fibers in the absorbent layer may be secured together by latex bonding or thermal bonding or hydrogen bonding or a combination of any bonding technique or other securing mechanism. In some embodiments, the absorbent layer is formed by fibers which operate to lock super-absorbent particles within the absorbent layer. This helps ensure that super-absorbent particles do not move external to the absorbent layer and towards an underlying wound bed. This is particularly helpful because when negative pressure is applied there is a tendency for the absorbent pad to collapse downwards and this action would push super-absorbent particle matter into a direction towards the wound bed if they were not locked away by the fibrous structure of the absorbent layer.
The absorbent layer may comprise a layer of multiple fibers. Preferably, the fibers are strand-like and made from cellulose, polyester, viscose or the like. Preferably, dry absorbent particles are distributed throughout the absorbent layer ready for use. In some embodiments, the absorbent layer comprises a pad of cellulose fibers and a plurality of super absorbent particles. In additional embodiments, the absorbent layer is a non-woven layer of randomly orientated cellulose fibers.
Super-absorber particles/fibers may be, for example, sodium polyacrylate or carbomethoxycellulose materials or the like or any material capable of absorbing many times its own weight in liquid. In some embodiments, the material can absorb more than five times its own weight of 0.9% W/W saline, etc. In some embodiments, the material can absorb more than 15 times its own weight of 0.9% W/W saline, etc. In some embodiments, the material is capable of absorbing more than 20 times its own weight of 0.9% W/W saline, etc. Preferably, the material is capable of absorbing more than 30 times its own weight of 0.9% W/W saline, etc.
Preferably, the particles of superabsorber are very hydrophilic and grab the fluid as it enters the dressing, swelling up on contact. An equilibrium is set up within the dressing core whereby moisture passes from the superabsorber into the dryer surrounding area and as it hits the top film the film switches and the fluid vapor starts to be transpired. A moisture gradient is established within the dressing to continually remove fluid from the wound bed and ensure the dressing does not become heavy with exudate.
The absorbent layer can include at least one through hole. The through hole can be located so as to underlie the suction port as described with reference to
Use of one or more through holes in the absorption layer also has the advantage that during use if the absorbent layer contains a gel forming material, such as superabsorber, that material as it expands to absorb liquid, does not form a bather through which further liquid movement and fluid movement in general cannot pass. In this way each opening in the absorbent layer provides a fluid pathway between the lower transmission or spacer layer and the upper transmission or spacer layer to the wound facing surface of the filter and then onwards into the interior of the port.
These layers can be covered with one layer of a film or cover layer. The cover layer can include a filter that can be positioned over the absorbent layer, or a filter may be incorporated in the port 460 as described in International Application Publication No. WO 2013/175306 A2, U.S. Publication No. US2011/0282309, and U.S. Publication No. 2016/0339158 the entirety of which is hereby incorporated by reference. As shown in
The cover layer can include an aperture within the cover layer for providing fluid communication with a source of negative pressure or pump. The filter can be positioned in communication with the aperture in the wound cover. The aperture in the wound cover can be covered by a port 460. In some embodiments, the port 460 connects to a conduit for communication with a negative pressure source or pump. The port 460 can include a filter 420 provided to cover the aperture in the cover layer 430. In some embodiments, the filter 420 can be integral to the port 460. The filter 420 can include hydrophobic material to protect the pump and/or other components from liquid exudates. The filter 420 can block fluids while permitting gases to pass through. In some embodiments, the filter can be similar to the filter or filter system described in
Negative pressure can be lost at the wound bed when free absorbent capacity remains in the dressing. This can occur because some or all of the pores in the filter are blocked with liquid or particulates. In some embodiments, solutions are utilized to allow the full capacity of the dressing absorbent layer to be utilized whilst maintaining the air path between the source of negative pressure and the wound bed.
In dressing embodiments that utilize a cover layer directly over the absorbent layer the dressing can have a void underneath the filter which can fill with liquid, thus blocking the filter pores and preventing air flow to the wound bed. A spacer layer or transmission layer 490 can be used to provide a fluid flow path above the absorbent layer 450 preventing the blocking of the port 460. In some embodiments, the transmission layer 490 in the dressing can be provided above and below the absorbent layer. The transmission layer can be incompressible and maintain a path for fluid flow between the source of negative pressure and the wound bed, via the filter. In some embodiments, the transmission layer can encapsulate or wrap around the absorbent layer as shown in
In some embodiments, the transmission layer can be utilized to assist in distributing negative pressure over the wound site and facilitating transport of wound exudate and fluids into the wound dressing.
A lower portion of the transmission layer 490 of porous material can be located above the wound contact layer and below the absorbent layer and wrapped around the edges of the absorbent layer. As the transmission layer is wrapped around at least one edge of the absorbent layer, the transmission layer has an upper portion of the transmission layer that can be positioned between the cover layer and the absorbent layer. As used herein the edge of the absorbent layer or the dressing refers to the sides of the material that are substantially perpendicular to the wound surface and run along the height of the material.
In some embodiments, the transmission layer can be a porous layer. This spacer layer, or transmission layer, 490 allows transmission of fluid including liquid and gas away from a wound site into upper layers of the wound dressing as described with reference to
In some embodiments, the transmission layer can be formed from an apertured nonwoven fabric spacer layer formed from the two layers of nonwoven fabric as described previously herein and illustrated in
In some embodiments, the plurality apertures of the nonwoven fabric layer can form a channel. The channels or apertures created in the nonwoven material can be utilized for the structure they provide in the material. For example, in some embodiments, the spacer layer formed from the nonwoven fabric layers as described herein can remain open upon application of negative pressure to the layer and/or a wound dressing. In some embodiments, the apertures, channels, and/or slits of the nonwoven fabric layer can allow for unique fluid management properties. In some embodiments, the layer formed from the two nonwoven fabric layers can have the performance benefits of a 3D spacer fabric or other spacer fabric described herein in terms of compression under loading and compression recovery. In such embodiments, the apertured nonwoven spacer layer can allow transmission of fluid including liquid and gas away from a wound site into upper layers of the wound dressing.
In some embodiments, the transmission layer can be formed from a three dimensional nonwoven spacer layer construction as described previously herein and illustrated in
In some embodiments, the 3D structure can be layered on top of one another or with traditional nonwovens to create a spacer type layer for use in a wound dressing.
For example, in some embodiments, the spacer layer formed from the nonwoven layers as described herein can remain open upon compression and/or application of negative pressure to the layer and/or a wound dressing. In some embodiments, the three dimensional structure of the nonwoven spacer layer can allow for unique fluid management properties. In some embodiments, the three dimensional nonwoven spacer layer formed from the nonwoven fabric layers can have the performance benefits of a 3D spacer fabric or other spacer fabric described herein in terms of compression under loading and compression recovery. In such embodiments, the three dimensional nonwoven spacer layer can allow transmission of fluid including liquid and gas away from a wound site into upper layers of the wound dressing.
The port 460 can be positioned either above the top film or cover layer 430 at one end or in the center of the dressing. The port can be positioned over the aperture in the top film and can contain or be placed over the filter 420. As described herein, providing the transmission layer above and below and wrapped around at least one side of the absorbent layer can prevent the filter from becoming blocked with liquid or particulates, by allowing the distribution of fluid through the wrapped spacer layer until the full absorbent capacity of the dressing materials have been reached. This can increase the wear time of the wound dressing by prolonging delivery of negative pressure to the wound bed. In some embodiments, the dressing with the configuration of layers as described herein has demonstrated a longer delivery period of NPWT to the wound contact surface compared to wound dressing without the transmission layer between the absorbent layer and the cover layer and without the transmission layer wrapped around the absorbent layer.
The transmission layer 490 can be wrapped around the absorbent layer 450 to disperse the vacuum throughout the dressing. In some embodiments, the transmission layer 490 can be manufactured as one flat piece of material that during assembly of the dressing is positioned on the bottom surface of the absorbent layer 450, wrapped around the ends of the absorbent layer 450, and the two ends of the spacer layer 490 are folded over the top surface of the absorbent layer 450 completely or partially covering the top surface of the absorbent layer 450. In such embodiments, the upper transmission layer 490 can have a break 495 in the transmission material where the two folded over ends of the transmission material 490 meet as shown in
Providing the transmission layer between the port and the absorbent layer prevents fluid or exudate removed from the wound from blocking the port and/or filter within the port. There can be some free particles in the hole of the absorbent layer positioned below the filter. The loose free particles in the hole can gel and block the hole and/or filter area. Therefore, the upper transmission layer can keep the superabsorber particles clear from the filter and allow the dressing to fill completely. In some embodiments, the transmission layer wrapped around the absorbent layer allow the port to be located at any location with respect to gravity. The transmission layer positioned above the absorbent layer can eliminate the concerns of the fluid or exudate removed from the wound from blocking the port and/or filter within the port on the section of the absorbent layer that is filled first.
As shown in
In some embodiments, the first and second transmission layer 326a, 326b can include a 3D fabric. In some embodiments, the first and second transmission layers can include an apertured nonwoven fabric spacer layer formed from the two layers of nonwoven fabric as described previously herein and illustrated in
In some embodiments, the plurality apertures of the nonwoven fabric layer can form a channel. The channels or apertures created in the nonwoven material can be utilized for the structure they provide in the material. For example, in some embodiments, the spacer layer formed from the nonwoven fabric layers as described herein can remain open upon application of negative pressure to the layer and/or a wound dressing. In some embodiments, the apertures, channels, and/or slits of the nonwoven fabric layer can allow for unique fluid management properties. In some embodiments, the layer formed from the two nonwoven fabric layers can have the performance benefits of a 3D spacer fabric or other spacer fabric described herein in terms of compression under loading and compression recovery. In such embodiments, the apertured nonwoven spacer layer can allow transmission of fluid including liquid and gas away from a wound site into upper layers of the wound dressing.
In some embodiments, the first and second transmission layers 326a, 326b may be formed of a material having a three dimensional structure. For example, a knitted or woven spacer fabric (for example Baltex 7970 weft knitted polyester) or a non-woven fabric could be used as described previously. The first and second transmission layers 326a, 326b can allow transmission of fluid including liquid and gas away from a wound site into the layers of the wound dressing. In particular, the first and second transmission layers 326a, 326b preferably ensures that an open air channel can be maintained to communicate negative pressure over the wound area and throughout the wound dressing even when the absorbent layer has absorbed substantial amounts of exudates.
In some embodiments, the first and second transmission layer 326a, 326b can include a 3D fabric. In some embodiments, the first and second transmission layers can include a three dimensional nonwoven spacer layer construction as described previously herein and illustrated in
In some embodiments, the 3D structure can be layered on top of one another or with traditional nonwovens to create a spacer type layer for use in a wound dressing.
For example, in some embodiments, the spacer layer formed from the nonwoven layers as described herein can remain open upon compression and/or application of negative pressure to the layer and/or a wound dressing. In some embodiments, the three dimensional structure of the nonwoven spacer layer can allow for unique fluid management properties. In some embodiments, the three dimensional nonwoven spacer layer formed from the nonwoven fabric layers can have the performance benefits of a 3D spacer fabric or other spacer fabric described herein in terms of compression under loading and compression recovery. In such embodiments, the three dimensional nonwoven spacer layer can allow transmission of fluid including liquid and gas away from a wound site into upper layers of the wound dressing.
A layer 2105 of porous material can be located above the wound contact layer 2102. This porous layer, or transmission layer, 2105 allows transmission of fluid including liquid and gas away from a wound site into upper layers of the wound dressing. In particular, the transmission layer 2105 preferably ensures that an open air channel can be maintained to communicate negative pressure over the wound area even when the absorbent layer has absorbed substantial amounts of exudates. The layer 2105 should preferably remain open under the typical pressures that will be applied during negative pressure wound therapy as described above, so that the whole wound site sees an equalized negative pressure.
In some embodiments, the transmission layer 2105 may be an apertured nonwoven fabric spacer layer formed from the two layers of nonwoven fabric as described previously herein and illustrated in
In some embodiments, the plurality apertures of the nonwoven fabric layer can form a channel. The channels or apertures created in the nonwoven material can be utilized for the structure they provide in the material. For example, in some embodiments, the spacer layer formed from the nonwoven fabric layers as described herein can remain open upon application of negative pressure to the layer and/or a wound dressing. In some embodiments, the apertures, channels, and/or slits of the nonwoven fabric layer can allow for unique fluid management properties. In some embodiments, the layer formed from the two nonwoven fabric layers can have the performance benefits of a 3D spacer fabric or other spacer fabric described herein in terms of compression under loading and compression recovery. In such embodiments, the apertured nonwoven spacer layer can allow transmission of fluid including liquid and gas away from a wound site into upper layers of the wound dressing.
In some embodiments, the transmission layer 2105 may be a three dimensional nonwoven spacer layer construction as described previously herein and illustrated in
In some embodiments, the 3D structure can be layered on top of one another or with traditional nonwovens to create a spacer type layer for use in a wound dressing.
For example, in some embodiments, the spacer layer formed from the nonwoven layers as described herein can remain open upon compression and/or application of negative pressure to the layer and/or a wound dressing. In some embodiments, the three dimensional structure of the nonwoven spacer layer can allow for unique fluid management properties. In some embodiments, the three dimensional nonwoven spacer layer formed from the nonwoven fabric layers can have the performance benefits of a 3D spacer fabric or other spacer fabric described herein in terms of compression under loading and compression recovery. In such embodiments, the three dimensional nonwoven spacer layer can allow transmission of fluid including liquid and gas away from a wound site into upper layers of the wound dressing.
In some embodiments, the layer 2105 may be formed of a material having a three dimensional structure. For example, a knitted or woven spacer fabric (for example Baltex 7970 weft knitted polyester) or a non-woven fabric could be used.
A layer 2110 of absorbent material is provided above the transmission layer 2105. The absorbent material, which comprise a foam or non-woven natural or synthetic material, and which may optionally comprise a super-absorbent material, forms a reservoir for fluid, particularly liquid, removed from the wound site. In some embodiments, the layer 2100 may also aid in drawing fluids towards the backing layer 2140.
With reference to
The material of the absorbent layer 2110 may also prevent liquid collected in the wound dressing 2100 from flowing freely within the dressing, and preferably acts so as to contain any liquid collected within the absorbent layer 2110. The absorbent layer 2110 also helps distribute fluid throughout the layer via a wicking action so that fluid is drawn from the wound site and stored throughout the absorbent layer. This helps prevent agglomeration in areas of the absorbent layer. The capacity of the absorbent material must be sufficient to manage the exudates flow rate of a wound when negative pressure is applied. Since in use the absorbent layer experiences negative pressures the material of the absorbent layer is chosen to absorb liquid under such circumstances. A number of materials exist that are able to absorb liquid when under negative pressure, for example superabsorber material. The absorbent layer 2110 may typically be manufactured from ALLEVYN™ foam, Freudenberg 114-224-4 and/or Chem-Posite™11C-450. In some embodiments, the absorbent layer 2110 may comprise a composite comprising superabsorbent powder, fibrous material such as cellulose, and bonding fibers. In a preferred embodiment, the composite is an airlaid, thermally-bonded composite.
An orifice 2144 is preferably provided in the backing layer 2140 to allow a negative pressure to be applied to the dressing 2100. A suction port 2150 is preferably attached or sealed to the top of the backing layer 2140 over an orifice 2144 made into the dressing 2100, and communicates negative pressure through the orifice 2144. A length of tubing may be coupled at a first end to the suction port 2150 and at a second end to a pump unit (not shown) to allow fluids to be pumped out of the dressing. The port may be adhered and sealed to the backing layer 2140 using an adhesive such as an acrylic, cyanoacrylate, epoxy, UV curable or hot melt adhesive. The port 2150 is formed from a soft polymer, for example a polyethylene, a polyvinyl chloride, a silicone or polyurethane having a hardness of 30 to 90 on the Shore A scale. In some embodiments, the port 2150 may be made from a soft or conformable material.
Preferably the absorbent layer 2110 and the obscuring layer 2107 include at least one through hole 2145 located so as to underlie the port 2150. Of course, the respective holes through these various layers 2107, 2140, and 2110 may be of different sizes with respect to each other. As illustrated in
The aperture or through-hole 2144 is preferably provided in the absorbent layer 2110 and the obscuring layer 2107 beneath the orifice 2144 such that the orifice is connected directly to the transmission layer 2105. This allows the negative pressure applied to the port 2150 to be communicated to the transmission layer 2105 without passing through the absorbent layer 2110. This ensures that the negative pressure applied to the wound site is not inhibited by the absorbent layer as it absorbs wound exudates. In other embodiments, no aperture may be provided in the absorbent layer 2110 and/or the obscuring layer 2107, or alternatively a plurality of apertures underlying the orifice 2144 may be provided.
The backing layer 2140 is preferably gas impermeable, but moisture vapor permeable, and can extend across the width of the wound dressing 2100. The backing layer 2140, which may for example be a polyurethane film (for example, Elastollan SP9109) having a pressure sensitive adhesive on one side, is impermeable to gas and this layer thus operates to cover the wound and to seal a wound cavity over which the wound dressing is placed. In this way an effective chamber is made between the backing layer 2140 and a wound site where a negative pressure can be established. The backing layer 2140 is preferably sealed to the wound contact layer 2102 in a border region 2200 around the circumference of the dressing, ensuring that no air is drawn in through the border area, for example via adhesive or welding techniques. The backing layer 2140 protects the wound from external bacterial contamination (bacterial bather) and allows liquid from wound exudates to be transferred through the layer and evaporated from the film outer surface. The backing layer 2140 preferably comprises two layers; a polyurethane film and an adhesive pattern spread onto the film. The polyurethane film is preferably moisture vapor permeable and may be manufactured from a material that has an increased water transmission rate when wet.
In some embodiments, the absorbent layer 2110 may be of a greater area than the transmission layer 2105, such that the absorbent layer overlaps the edges of the transmission layer 2105, thereby ensuring that the transmission layer does not contact the backing layer 2140. This provides an outer channel 2115 of the absorbent layer 2110 that is in direct contact with the wound contact layer 2102, which aids more rapid absorption of exudates to the absorbent layer. Furthermore, this outer channel 2115 ensures that no liquid is able to pool around the circumference of the wound cavity, which may otherwise seep through the seal around the perimeter of the dressing leading to the formation of leaks.
The wound dressing 1400 can be constructed similar to the embodiments of
As illustrated in
The obscuring layer 1404 can be positioned at least partially over the absorbent material 1402. In some embodiments, the obscuring layer 1404 can be positioned adjacent to the backing layer, or can be positioned adjacent to any other dressing layer desired. In some embodiments, the obscuring layer 1404 can be adhered to or integrally formed with the backing layer and/or the absorbent material.
As illustrated in
In some embodiments, the obscuring layer 1404 can help to reduce the unsightly appearance of a dressing during use, by using materials that impart partial obscuring or masking of the dressing surface. The obscuring layer 1404 in one embodiment only partially obscures the dressing, to allow clinicians to access the information they require by observing the spread of exudate across the dressing surface. The partial masking nature of this embodiment of the obscuring layer enables a skilled clinician to perceive a different color caused by exudate, blood, by-products etc. in the dressing allowing for a visual assessment and monitoring of the extent of spread across the dressing. However, since the change in color of the dressing from its clean state to a state containing exudate is only a slight change, the patient is unlikely to notice any aesthetic difference. Reducing or eliminating a visual indicator of wound exudate from a patient's wound is likely to have a positive effect on their health, reducing stress for example.
In some embodiments, the obscuring layer can be formed from a non-woven fabric (for example, polypropylene), and may be thermally bonded using a diamond pattern with 19% bond area. In various embodiments, the obscuring layer can be hydrophobic or hydrophilic. Depending on the application, in some embodiments, a hydrophilic obscuring layer may provide added moisture vapor permeability. In some embodiments, however, hydrophobic obscuring layers may still provide sufficient moisture vapor permeability (i.e., through appropriate material selection, thickness of the obscuring layer), while also permitting better retention of dye or color in the obscuring layer. As such, dye or color may be trapped beneath the obscuring layer. In some embodiments, this may permit the obscuring layer to be colored in lighter colors or in white. In the preferred embodiment, the obscuring layer is hydrophobic. In some embodiments, the obscuring layer material can be sterilizable using ethylene oxide. Other embodiments may be sterilized using gamma irradiation, an electron beam, steam or other alternative sterilization methods. Additionally, in various embodiments the obscuring layer can colored or pigmented, e.g., in medical blue. The obscuring layer may also be constructed from multiple layers, including a colored layer laminated or fused to a stronger uncolored layer. Preferably, the obscuring layer is odorless and exhibits minimal shedding of fibers.
The absorbent layer 1402, itself may be colored or tinted in some embodiments, however, so that an obscuring layer is not necessary. The dressing may optionally include a means of partially obscuring the top surface. This could also be achieved using a textile (knitted, woven, or non-woven) layer without openings, provided it still enables fluid evaporation from the absorbent structure. It could also be achieved by printing an obscuring pattern on the top film, or on the top surface of the uppermost pad component, using an appropriate ink or colored pad component (yarn, thread, coating) respectively. Another way of achieving this would be to have a completely opaque top surface, which could be temporarily opened by the clinician for inspection of the dressing state (for example through a window), and closed again without compromising the environment of the wound. Additionally,
The viewing windows 1403 may take several configurations. In some embodiments, the viewing windows 1403 may comprise an array of regularly spaced uncolored dots (holes) made into the obscuring layer 1404. While the dots illustrated here are in a particular pattern, the dots may be arranged in different configurations, or at random. The viewing windows 1403 are preferably configured so as to permit a patient or caregiver to ascertain the status of the absorbent layer, in particular to determine its saturation level, as well as the color of the exudate (e.g., whether excessive blood is present). By having one or more viewing windows, the status of the absorbent layer can be determined in an unobtrusive manner that is not aesthetically unpleasing to a patient. Because a large portion of the absorbent layer may be obscured, the total amount of exudate may therefore be hidden. As such, the status and saturation level of the absorbent layer 1402 may therefore present a more discreet external appearance so as to reduce patient embarrassment and visibility and thereby enhance patient comfort. In some configurations, the one or more viewing windows 1403 may be used to provide a numerical assessment of the degree of saturation of the dressing 1400. This may be done electronically (e.g., via a digital photograph assessment), or manually. For example, the degree of saturation may be monitored by counting the number of viewing windows 1403 which may be obscured or tinted by exudate or other wound fluids.
In some embodiments, the absorbent layer 1402 or the obscuring layer 1404, in particular the colored portion of the absorbent layer, may comprise (or be colored because of) the presence of an auxiliary compound. The auxiliary compound may in some embodiments be activated charcoal, which can act to absorb odors. The use of antimicrobial, antifungal, anti-inflammatory, and other such therapeutic compounds is also possible. In some embodiments, the color may change as a function of time (e.g., to indicate when the dressing needs to be changed), if the dressing is saturated, or if the dressing has absorbed a certain amount of a harmful substance (e.g., to indicate the presence of infectious agents). In some embodiments, the one or more viewing windows 1403 may be monitored electronically, and may be used in conjunction with a computer program or system to alert a patient or physician to the saturation level of the dressing 1400.
Each of the documents referred to above is incorporated herein by reference.
Except in the Examples, or where otherwise explicitly indicated, all numerical quantities in this description specifying amounts of materials, processing conditions and the like, are to be understood as modified by the word “about.”
While the invention has been explained in relation to its preferred embodiments, it is to be understood that various modifications thereof will become apparent to those skilled in the art upon reading the specification. Therefore, it is to be understood that the invention disclosed herein is intended to cover such modifications as fall within the scope of the appended claims.
This application claims priority to U.S. Provisional Patent Application No. 62/527,922, filed on Jun. 30, 2017, and U.S. Provisional Patent Application No. 62/527,959, filed on Jun. 30, 2017. All of these applications are hereby incorporated by reference in their entireties and made part of this disclosure.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2018/066575 | 6/21/2018 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62527922 | Jun 2017 | US | |
| 62527959 | Jun 2017 | US |
