Sensor-enabled wound monitoring and treatment device

Abstract

The invention discloses a sensor-enabled wound monitoring and treatment device. In some embodiments, a wound dressing may be used that includes a plurality of sensors or sensors separate from the wound dressing to monitor characteristics of the wound or identify one or more risk factors or conditions that may trap the wound as the wound heals. In some embodiments, a wound dressing configured to be positioned in contact with a wound includes a substantially flexible substrate supporting one or more sensors. The one or more sensors may include a temperature sensor, a conductivity sensor, a multispectral optical measurement sensor, a pH sensor, a pressure sensor, a colorimetric sensor, an optical sensor, an ultraviolet (UV) sensor, or an infrared (IR) sensor.

Description

[0001] This invention is a divisional application, the parent application number of which is 201780027165.X, the application date is May 12, 2017, and the name of the invention is “Sensor-enabled wound monitoring and treatment device”. Technical Field

[0002] Embodiments described herein relate to devices, systems, and methods for monitoring or treating wounds, for example, using a dressing in combination with negative pressure wound therapy. Background Art

[0003] Treating open or chronic wounds that are too large to close spontaneously or otherwise unhealable by applying negative pressure to the wound site is well known in the art. Negative pressure wound therapy (NPWT) systems currently known in the art generally involve placing a fluid-impermeable or semi-permeable covering over the wound, sealing the covering to the patient's tissue surrounding the wound using various means, and connecting a negative pressure source (e.g., a vacuum pump) to the covering in a manner that generates and maintains negative pressure beneath the covering. This negative pressure is believed to promote wound healing by promoting the formation of granulation tissue at the wound site and aiding the body's normal inflammatory process while removing excess fluid that may contain adverse cytokines or bacteria. However, further improvements in NPWT are needed to fully realize the benefits of treatment.

[0004] Many different types of wound dressings are known for use in conjunction with 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 wound contact layer and a superabsorbent layer beneath a backing layer to provide a canisterless system for treating wounds with NPWT. The wound dressing can be sealed to a suction port that provides a connection to a length of tubing that can be used to pump fluid out of the dressing or to transfer negative pressure from a pump to the wound dressing. Additionally, the RENASYS-F, RENASYS-G, RENASYS-AB, and RENASYS-F / AB available from Smith & Nephew are additional examples of NPWT wound dressings and systems. Another example of a multi-layer wound dressing is the ALLEVYN Life dressing available from Smith & Nephew, which includes a moist wound environment dressing for treating wounds without the use of negative pressure.

[0005] However, existing dressings used for negative pressure wound therapy or other wound treatments provide little visualization or information about the condition of the wound site beneath the dressing. This can require premature dressing changes before the desired level of wound healing has occurred, or, for absorbent dressings, before the full absorptive capacity of the dressing has been reached to allow clinicians to inspect the healing and status of the wound. Some current dressings have limited or unsatisfactory methods or features for providing information about the wound's condition. Summary of the Invention

[0006] In some embodiments, a wound monitoring device includes a wound dressing configured to be positioned in contact with a wound and comprising at least one substantially flexible substrate supporting one or more sensors.

[0007] The apparatus of the preceding paragraph may include one or more of the following features. The at least one substantially flexible substrate may include a substantially flexible printed circuit, which may include a flexible polymer. The at least one substantially flexible substrate may include a substantially flexible non-conductive mesh. The one or more sensors may include a plurality of sensors electrically connected to each other. The plurality of sensors may be electrically connected to a controller and a power source. The one or more sensors may include one or more temperature sensors, conductivity sensors, multispectral optical measurement sensors, pH sensors, pressure sensors, colorimetric sensors, optical sensors, ultraviolet (UV) sensors, or infrared (IR) sensors.

[0008] The apparatus of any of the preceding paragraphs may include one or more of the following features. The apparatus may include a controller in electrical communication with the one or more sensors, the controller configured to receive data from the one or more sensors and transmit the data to a processing device, the processing device configured to process the data collected by the one or more sensors using host software to determine one or more conditions associated with the wound. At least one of the controller or the processing device may be configured to indicate that the wound is healing based on the one or more conditions associated with the wound. The controller may be configured to communicate wirelessly with at least one of the one or more sensors or the processing device. The controller may be configured to communicate electrically with at least one of the one or more sensors or the processing device via a wired connection. The processing device may include a personal computer (PC), a tablet computing device, a smartphone, or a custom computing device. The data collected by the one or more sensors may be configured to be transmitted to a cloud.

[0009] The apparatus of any of the preceding paragraphs may include one or more of the following features. The wound dressing may include a wound contact layer, and the substrate may be located on or in the wound contact layer. The wound contact layer may include a first wound contact layer and a second wound contact layer, wherein the substrate is sandwiched between the first wound contact layer and the second wound contact layer. At least one of the one or more sensors may be configured to be in direct contact with the wound, and at least one of the one or more sensors may be encapsulated between the first wound contact layer and the second wound contact layer. The one or more sensors may include at least a first sensor configured to be in direct contact with the wound and at least a second sensor configured not to contact the wound. The apparatus may include an absorbent layer located above the wound contact layer and a backing layer located above the wound contact layer, wherein the wound contact layer is sealed to the backing layer. The apparatus may include a port on the backing layer, the port being configured to connect the wound dressing to a source of negative pressure.

[0010] The apparatus of any of the preceding paragraphs may include one or more of the following features. The wound dressing may be included in a multi-layer wound dressing configured to treat a wound without the use of negative pressure. The apparatus may include a wound packing layer and a drape configured to be positioned over the wound separately from the wound dressing. The apparatus may include a negative pressure source configured to be in fluid communication with the wound dressing and further configured to apply negative pressure to the wound.

[0011] In some embodiments, a wound monitoring device includes a wound dressing configured to be positioned in contact with one or more of a wound or skin surrounding a wound, the wound dressing including at least one substantially flexible substrate supporting a plurality of sensors. A first sensor of the plurality of sensors may be located on the substrate and configured to obtain a measurement of the skin surrounding the wound.

[0012] The apparatus of any of the preceding paragraphs may include one or more of the following features. A second sensor of the plurality of sensors may be located on the substrate and configured to obtain measurements of the wound. The substrate may be sized to extend at least partially beyond the area of ​​the wound and configured to be located at least partially above the skin surrounding the wound. The wound dressing may include a wound contact layer. The at least one substantially flexible substrate may include at least one of a substantially flexible printed circuit or a substantially flexible non-conductive mesh. The substantially flexible printed circuit may include a flexible polymer. At least some of the plurality of sensors may be electrically connected to each other.

[0013] The apparatus of any of the preceding paragraphs may include one or more of the following features. The plurality of sensors may be electrically connected to a controller and a power source. The controller may be configured to receive data from the plurality of sensors and transmit the received data to a computing device, the computing device configured to process the received data to determine one or more conditions associated with the wound. At least one of the controller or the processing device may be configured to indicate that the wound is healing based on the one or more conditions associated with the wound. The plurality of sensors may include one or more temperature sensors, conductivity sensors, multispectral optical measurement sensors, pH sensors, pressure sensors, colorimetric sensors, optical sensors, ultraviolet (UV) sensors, or infrared (IR) sensors. The plurality of sensors may include a skin elasticity sensor configured to perform an ultrasound scan of the skin area surrounding the wound.

[0014] In some implementations, a method of operating or using the apparatus of any of the preceding paragraphs is provided.

[0015] In some embodiments, a method of operating a wound monitoring device includes monitoring at least one of a wound or skin surrounding a wound with a wound dressing configured to be positioned in contact with the wound. The wound dressing may include at least one substantially flexible substrate supporting one or more sensors.

[0016] The method of the preceding paragraph may include one or more of the following features. The method may include monitoring the skin surrounding a wound with a first sensor located on the substrate, and monitoring the wound with a second sensor located on the substrate. The one or more sensors may include one or more temperature sensors, conductivity sensors, multispectral optical measurement sensors, pH sensors, pressure sensors, colorimetric sensors, optical sensors, ultraviolet (UV) sensors, or infrared (IR) sensors. The substrate may be sized to extend at least partially beyond the area of ​​the wound and configured to be positioned at least partially above the skin surrounding the wound. The at least one substantially flexible substrate may include at least one of a substantially flexible printed circuit or a substantially flexible non-conductive mesh. The substantially flexible printed circuit may include a flexible polymer. At least some of the one or more sensors may be electrically connected to each other.

[0017] The method of the preceding paragraph may include one or more of the following features. The one or more sensors may be electrically connected to a controller and a power source. The method may include receiving data from the one or more sensors by the controller and transmitting the received data to a computing device, the computing device being configured to process the received data to determine one or more conditions associated with the wound. The method may include indicating that the wound is healing based on the one or more conditions associated with the wound. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Embodiments of the present disclosure will now be described hereinafter, by way of example only, with reference to the accompanying drawings, in which: Figure 1A A negative pressure wound therapy system employing a flexible fluid connector and a wound dressing capable of absorbing and storing wound exudate is shown according to some embodiments; Figure 1B A negative pressure wound therapy system employing a flexible fluid connector and a wound dressing capable of absorbing and storing wound exudate is shown according to some embodiments; Figure 2A A negative pressure wound therapy system employing a flexible fluid connector and a wound dressing capable of absorbing and storing wound exudate is shown according to some embodiments; Figure 2B shows a cross-section of a fluid connector connected to a wound dressing according to some embodiments; Figure 2C shows a negative pressure wound therapy system according to some embodiments; Figure 2D shows a wound treatment system employing a wound dressing capable of absorbing and storing wound exudate to be used in the absence of negative pressure, according to some embodiments; Figure 3A shows a sensor array according to some embodiments, illustrating placement of sensors incorporated into a wound dressing component; Figure 3B shows a flexible sensor array including a sensor array portion, a tail portion, and a connector pad end portion according to some embodiments; Figures 3C-3F An embodiment of a flexible printed circuit with four different sensor array geometries is shown; Figure 3G Shown Figure 3D An embodiment of a sensor array portion 301 of a sensor array design is shown in more detail in FIG; Figure 3H shows a flexible sensor array incorporated into a perforated wound contact layer according to some embodiments; Figure 3I shows a control module according to some embodiments; Figures 3J-3K Results of an optical sensor used on tissue and the scattering and attenuation of light in the tissue are shown, according to some embodiments. Figure 3J shows the intensity loss of light entering the tissue, and Figure 3K The response of the optical detector is shown; Figures 3L-3M shows measurements taken using an SpO2 sensor in its original form, according to some embodiments; Figure 3N shows a wound contact layer according to some embodiments, the wound contact layer comprising an aperture and curved slits extending radially from a central aperture; Figure 3O shows a wound contact layer according to some embodiments, the wound contact layer comprising an aperture and a curved slit forming a partial circle and a slit extending from the periphery of the circle to the center of the wound contact layer; Figure 3P shows a wound contact layer according to some embodiments, the wound contact layer comprising an aperture and slits extending radially from a central aperture; Figure 3Q shows the spectral response of an optical detector according to some embodiments; and Figure 4A -D illustrates the use and application of a wound treatment system on a patient according to some embodiments. DETAILED DESCRIPTION

[0019] Embodiments disclosed herein relate to devices and methods for monitoring or treating wounds with or without pressure reduction, including, for example, a negative pressure source and wound dressing components and devices. The devices and components, including wound covering material and filler material or inner layer (if any), are sometimes collectively referred to herein as a dressing. In some embodiments, the wound dressing can be configured for use without pressure reduction.

[0020] Some embodiments disclosed herein relate to wound therapy for the human or animal body. Thus, any reference herein to a wound may refer to a wound on the human or animal body, and any reference herein to the body may refer to the human or animal body. In addition to having its broad ordinary meaning, the term "wound" as used herein includes any part of the body of a patient that can be treated with negative pressure. It should be understood that the term "wound" should be broadly interpreted to mean and encompass open wounds and closed wounds, where the skin is torn, cut or punctured, or where the trauma has caused a contusion, or any other surface or other condition or defect on the patient's skin, or other aspects that may benefit from reduced pressure treatment. Thus, a wound is broadly defined as any damaged tissue area where fluid may or may not be produced. Examples of such wounds include, but are not limited to, abdominal wounds or other large or open wounds resulting from surgery, trauma, sternotomy, fasciotomy, or other conditions, dehiscent wounds, acute wounds, chronic wounds, subacute and dehiscent wounds, traumatic wounds, flaps and skin grafts, lacerations, abrasions, contusions, burns, diabetic ulcers, pressure ulcers, stomas, surgical wounds, traumatic ulcers, arterial ulcers, and venous ulcers.

[0021] Such wounds can be treated using negative pressure wound therapy, where reduced pressure, or negative pressure, can be applied to the wound to facilitate and promote wound healing. It will also be appreciated that the wound dressings and methods as described herein can be applied to other parts of the body and are not necessarily limited to the monitoring, prevention, and treatment of wounds.

[0022] It should be understood that embodiments of the present disclosure are generally suitable for use in topical negative pressure ("TNP") therapy systems. Briefly, negative pressure wound therapy aids in the closure and healing of various types of "refractory" wounds by reducing tissue edema, promoting blood flow and granulation tissue formation, removing excess fluid, and reducing bacterial load (thus reducing the risk of infection). Furthermore, the therapy allows for less wound disturbance, enabling faster healing. TNP therapy systems can also assist in the healing of surgically closed wounds by removing fluid and helping to stabilize tissue immediately adjacent to the closure site. Additional beneficial uses of TNP therapy can be found in grafts and flaps, where excess fluid removal is important and close proximity of the graft to the tissue is necessary to ensure tissue viability.

[0023] As used herein, a reduced pressure level or negative pressure level (such as -X mmHg) represents a pressure level 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.). In some embodiments, the local ambient atmospheric pressure is used as a reference point, and this local atmospheric pressure may not necessarily be, for example, 760 mmHg. Thus, a negative pressure value of -X mmHg reflects an absolute pressure that is X mmHg lower than, for example, 760 mmHg, or in other words, an absolute pressure of (760-X) mmHg. Furthermore, a negative pressure that is "lower" or "smaller" than X mmHg corresponds to a pressure that is closer to atmospheric pressure (e.g., -40 mmHg is smaller than -60 mmHg). A negative pressure that is "higher" or "larger" than -X mmHg corresponds to a pressure that is further away from atmospheric pressure (e.g., -80 mmHg is larger than -60 mmHg).

[0024] The negative pressure range of some embodiments of the present disclosure can be approximately -80 mmHg, or between approximately -20 mmHg and -200 mmHg or greater. It should be noted that these pressures are based on normal ambient atmospheric pressure (which can be 760 mmHg). Therefore, in reality, -200 mmHg would be around 560 mmHg. In some embodiments, the pressure range can be between approximately -40 mmHg and -150 mmHg. Alternatively, a pressure range of up to -75 mmHg, up to -80 mmHg, or exceeding -80 mmHg can be used. In other embodiments, a pressure range below -75 mmHg can be used. Alternatively, the negative pressure device can supply a pressure range exceeding approximately -100 mmHg, or even -150 mmHg.

[0025] In some embodiments of the wound closure devices described herein, increased wound contraction can cause increased tissue expansion in the surrounding wound tissue. This effect can be enhanced by varying the force applied to the tissue, for example by varying the negative pressure applied to the wound over time, which can be combined with increasing the tension applied to the wound via various embodiments of the wound closure device. In some embodiments, the negative pressure can be varied over time, for example using a sine wave, a square wave, or synchronized with one or more patient physiological indicators (e.g., a heartbeat). Examples of such applications in which additional disclosure related to the foregoing can be found include U.S. Patent No. 8,235,955, entitled "Wound Treatment Apparatus and Method," issued on August 7, 2012; and U.S. Patent No. 7,753,894, entitled "Wound Cleansing Apparatus with Stress," issued on July 13, 2010. The disclosures of both patents are hereby incorporated herein by reference in their entirety.

[0026] Embodiments of the wound dressings, wound dressing components, wound treatment devices, and methods described herein may also be used in combination with or in addition to those described in International Application No. PCT / IB2013 / 001469, filed on May 22, 2013, and published on November 28, 2013 as WO 2013 / 175306 A2, entitled “APPARATUSES AND METHODS FOR NEGATIVE PRESSURE WOUND THERAPY,” and U.S. Patent Application No. 14 / 418,908, filed on January 30, 2015, and published on July 9, 2015 as US 2015 / 0190286 A1, entitled “WOUND DRESSING AND METHOD OF TREATMENT,” the disclosures of which are hereby incorporated by reference in their entireties. Embodiments of the wound dressings, wound dressing components, wound treatment devices, and methods described herein may also be used in combination with or in addition to those described in U.S. patent application Ser. No. 13 / 092,042, filed on April 21, 2011, and published as US2011 / 0282309, entitled “WOUND DRESSING AND METHOD OF USE,” and U.S. patent application Ser. No. 14 / 715,527, filed on May 18, 2015, and published as US2016 / 0339158 A1 on December 24, 2016, entitled “FLUIDIC CONNECTOR FOR NEGATIVE PRESSURE WOUNDTHERAPY,” the disclosures of which are hereby incorporated by reference in their entireties, including additional details regarding embodiments of wound dressings, wound dressing components and principles, and materials for wound dressings.

[0027] Furthermore, some embodiments involving TNP wound therapy comprising a wound dressing in combination with a pump and / or associated electronics as described herein may also be used in combination with or in addition to those described in International Application PCT / EP2016 / 059329, entitled “REDUCED PRESSURE APPARATUS AND METHODS,” filed on April 26, 2016 and published as WO 2016 / 174048 on November 3, 2016.

[0028] NPWT System Overview Figure 1A-B shows an embodiment of a negative pressure wound therapy system 10 using a wound dressing 100 in conjunction with a fluid connector 110. Here, the fluid connector 110 may include an elongated conduit, such as a bridge 120 having a proximal end 130 and a distal end 140, and an applicator 180 at the distal end 140 of the bridge 120. An optional coupling 160 may be arranged at the proximal end 130 of the bridge 120. A cap 170 may be provided with the system (and in some cases may be attached to the coupling 160 as shown). The cap 170 may be used to prevent fluid from leaking out of the proximal end 130. The system 10 may include a negative pressure source, such as a pump or negative pressure unit 150 capable of supplying negative pressure. The pump may include a tank or other container for storing wound exudate and other fluids that can be removed from the wound. The tank or container may also be provided separate from the pump. In, for example Figures 1A-1B In some embodiments shown, pump 150 can be a canisterless pump, such as the PICO™ pump sold by Smith & Nephew. Pump 150 can be connected to coupling 160 via tubing 190, or pump 150 can be connected directly to coupling 160 or directly to bridge 120. In use, dressing 100 is placed over a suitably prepared wound, which in some cases may be filled with a wound packing material, such as foam or gauze. Applicator 180 of fluid connector 110 has a sealing surface that is placed over the orifice of dressing 100 and seals to the top surface of dressing 100. Before, during, or after fluid connector 110 is connected to dressing 100, pump 150 is connected to coupling 160 via tubing 190, or directly to coupling 160 or bridge 120. The pump is then activated, thereby supplying negative pressure to the wound. Negative pressure can be applied until the desired level of wound healing is achieved.

[0029] Wound Dressing Overview like Figure 2A As shown in FIG, in some embodiments, the fluid connector 110 can include an enlarged distal end, or head 140 in fluid communication with the dressing 100, as will be described in more detail below. In one embodiment, the enlarged distal end has a rounded or circular shape. The head 140 is shown here as being positioned near an edge of the dressing 100, but can be positioned anywhere on the dressing. For example, some embodiments may provide a centered or off-center location that is not on or near an edge or corner of the dressing 100. In some embodiments, the dressing 10 may include two or more fluid connectors 110, each including one or more heads 140 in fluid communication therewith. In some embodiments, the head 140 may measure 30 mm along its widest edge. The head 140 forms at least a portion of the applicator 180 described above, which is configured to seal to the top surface of the wound dressing.

[0030] Figure 2B Shown through similar Figure 1BA cross-section of a wound dressing 10 and a fluid connector 110 is shown in FIG and described in International Patent Publication WO2013175306 A2, which is incorporated herein by reference in its entirety. The wound dressing 100, which may alternatively be any wound dressing embodiment disclosed herein or any combination of features of any number of the wound dressing embodiments disclosed herein, may be positioned over a wound site to be treated. The dressing 100 may be positioned to form a sealed cavity over the wound site. In some embodiments, the dressing 100 includes a top or cover layer, or a backing layer 220 attached to an optional wound contact layer 222, both of which are described in more detail below. These two layers 220, 222 are preferably joined or sealed together to define an interior space or chamber. This interior space or chamber may include additional structures that may be adapted to distribute or transmit negative pressure, store wound exudate and other fluids removed from the wound, and other functions, as explained in more detail below. Examples of such structures, described below, include a transmission layer 226 and an absorbent layer 221.

[0031] As used herein, an upper layer, top layer or upper layer refers to the layer that is furthest from the surface of the skin or wound when the dressing is in use and positioned on a wound. Thus, a lower surface, lower layer, bottom layer or underlying layer refers to the layer that is closest to the surface of the skin or wound when the dressing is in use and positioned on a wound.

[0032] like Figure 2B As shown in FIG, in some embodiments, the wound contact layer 222 may be a polyurethane or polyethylene layer, or other flexible or substantially flexible layer, that is made permeable to liquids and gases, for example, by a heat-stamping process, a laser ablation process, an ultrasound process, or in some other manner or otherwise. The wound contact layer 222 has a lower surface 224 (e.g., facing the wound) and an upper surface 223 (e.g., facing away from the wound). Perforations 225 preferably comprise through-holes in the wound contact layer 222 that allow fluid to flow through the layer 222. The wound contact layer 222 helps prevent tissue ingrowth into other materials of the wound dressing. In some embodiments, the perforations are small enough to meet this requirement while still allowing fluid to flow therethrough. For example, perforations formed as slits or holes having a size ranging from 0.025 mm to 1.4 mm are considered small enough to help prevent tissue ingrowth into the wound dressing while allowing wound exudate to flow into the dressing. In some configurations, the wound contact layer 222 can help maintain the integrity of the entire dressing 100 while also creating an airtight seal around the absorbent pad to maintain negative pressure at the wound.

[0033] Some embodiments of the wound contact layer 222 can also serve as a carrier for optional lower and upper adhesive layers (not shown). For example, a lower pressure-sensitive adhesive can be provided on the lower surface 224 of the wound dressing 100, while an upper pressure-sensitive adhesive layer can be provided on the upper surface 223 of the wound contact layer. The pressure-sensitive adhesive can be a silicone, hot melt, hydrocolloid, acrylic, or other such adhesive and can be applied to both sides, or alternatively, to both sides, a selected side, or neither side of the wound contact layer. When used, the lower pressure-sensitive adhesive layer can help adhere the wound dressing 100 to the skin surrounding the wound site. In some embodiments, the wound contact layer can include a perforated polyurethane film. The lower surface of the film can be provided with a silicone pressure-sensitive adhesive, and the upper surface can be provided with an acrylic pressure-sensitive adhesive, which can help the dressing maintain its integrity. In some embodiments, the polyurethane film layer can be provided with adhesive layers on both its upper and lower surfaces, and all three layers can be perforated.

[0034] A layer 226 of porous material may be positioned above the wound contact layer 222. This porous layer, or transfer layer 226, allows fluids, including liquids and gases, to transfer from the wound site into the upper layers of the wound dressing. Specifically, the transfer layer 226 can ensure open air channels, maintaining negative pressure across the wound area even when the absorbent layer absorbs significant amounts of exudate. In some embodiments, layer 226 should remain open at typical pressures, which will be applied during negative pressure wound therapy, as described above, so that a uniform negative pressure is observed across the wound site. Layer 226 can be formed from a material having a three-dimensional structure. For example, a knitted or woven spacer fabric (e.g., Baltex 7970 weft-knitted polyester) or a nonwoven fabric can be used.

[0035] In some embodiments, the transmission layer 226 comprises a 3D polyester spacer fabric layer comprising a top layer (i.e., the layer facing away from the wound bed during use) of 84 / 144 textured polyester, a bottom layer (i.e., the layer facing closer to the wound bed during use) of 10 denier flat polyester, and a third layer sandwiched between the two layers, the third layer being a region defined by knitted polyester viscose, cellulose, or similar monofilament fibers. Other materials and fibers of other linear mass densities may of course be used.

[0036] Although reference is made throughout this disclosure to monofilament fibers, it will be appreciated that multiple strands may be used as an alternative.Thus, the top spacer fabric has a greater number of filaments in the yarn used to form it than the filaments constituting the yarn used to form the bottom spacer fabric layer.

[0037] This difference in filament count between the spaced-apart layers helps control moisture flow through the transfer layer. Specifically, by having a greater filament count in the top layer, that is, the top layer is made of a yarn with more filaments than the yarn used for the bottom layer, liquid tends to be wicked more along the top layer than the bottom layer. In use, this difference tends to draw liquid away from the wound bed and into the central area of ​​the dressing, where the absorbent layer 221 helps lock the liquid away or itself wicks the liquid forward toward the cover layer where the liquid can transpire.

[0038] In some embodiments, to improve liquid flow through the transfer layer 226 (i.e., perpendicular to the channel region formed between the top and bottom spacer layers), the 3D fabric can be treated with a dry cleaning agent (e.g., but not limited to, Perchloroethylene) to help remove any manufacturing products, such as previously used mineral oils, fats, or waxes, that could interfere with the transfer layer's hydrophilicity. In some embodiments, an additional manufacturing step can subsequently be performed in which the 3D spacer fabric is washed in a hydrophilizing agent (e.g., but not limited to, Feran Ice 30 g / l available from Rudolph Group). This process step helps ensure that the surface tension on the material is very low, allowing liquids such as water to enter the 3D knitted fabric upon contact. This also helps control the flow of any liquid insult components of the exudate.

[0039] A layer of absorbent material 221 is provided over the transfer layer 226. The absorbent material, which may include foam or nonwoven natural or synthetic materials, and may optionally include superabsorbent materials, forms a reservoir for fluids (particularly liquids) removed from the wound site. In some embodiments, layer 10 may also assist in absorbing fluids toward the backing layer 220.

[0040] The material of the absorbent layer 221 also prevents liquid collected in the wound dressing 100 from freely flowing within the dressing and can be used to contain any liquid that collects within the dressing. The absorbent layer 221 also helps distribute liquid throughout the layer via a wicking action, so that fluid is absorbed from the wound site and stored throughout the absorbent layer. This helps prevent accumulation in areas of the absorbent layer. The capacity of the absorbent material must be sufficient to manage the flow rate of exudate from the wound when negative pressure is applied. Because the absorbent layer experiences negative pressure during use, the material of the absorbent layer is selected to absorb liquid under such conditions. Many materials exist that can absorb liquid under negative pressure, such as superabsorbent materials. The absorbent layer 221 can typically be made from ALLEVYN™ foam, Freudenberg 114-224-4, or Chem-Posite™ 11C-450. In some embodiments, the absorbent layer 221 may comprise a composite comprising a superabsorbent powder, a fibrous material such as cellulose, and binding fibers. In some embodiments, the composite is an airlaid, thermally bonded composite.

[0041] In some embodiments, the absorbent layer 221 is a nonwoven cellulose fiber layer having superabsorbent material in the form of dry particles dispersed throughout. The use of cellulose fibers introduces a rapid wicking element that helps quickly and evenly distribute liquid taken up by the dressing. The juxtaposition of multiple strands of fibers results in a strong capillary action within the fiber mat, which aids in distributing liquid. In this way, the superabsorbent material is efficiently supplied with liquid. The wicking action also helps to draw liquid into contact with the upper cover layer, helping to increase the transpiration rate of the dressing.

[0042] In some embodiments, an orifice, hole, or aperture 227 is provided in the backing layer 220 to allow negative pressure to be applied to the dressing 100. In certain embodiments, the fluid connector 110 is attached or sealed to the top of the backing layer 220 over the aperture 227 created in the dressing 100, and transmits negative pressure through the aperture 227. A length of tubing can be coupled to the fluid connector 110 at a first end and to a pump unit (not shown) at a second end to allow fluid to be pumped out of the dressing. In the case where the fluid connector is adhered to the top layer of the wound dressing, a length of tubing can be coupled to the first end of the fluid connector so that the tubing or conduit extends parallel to and away from the fluid connector, or generally to the top surface of the dressing. The fluid connector 110 can 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 fluid connector 110 can be formed from a soft polymer, such as polyethylene, polyvinyl chloride, silicone, or polyurethane, having a Shore A durometer of 30 to 90. In some embodiments, the fluid connector 110 can be made from a soft or conformable material.

[0043] In some embodiments, the absorbent layer 221 includes at least one through-hole 228 positioned so as to be located beneath the fluid connector 110. In some embodiments, the through-hole 228 can be the same size as the opening 227 in the backing layer, or can be larger or smaller. Figure 2B As shown in , a single through-hole can be used to create an opening located below the fluid connector 110. It will be appreciated that multiple openings may alternatively be used. Alternatively, if more than one port is used according to certain embodiments of the present disclosure, one or more openings may be created in the absorbent layer and the obscuring layer in registration with each corresponding fluid connector. Although not required for certain embodiments of the present disclosure, the use of through-holes in the superabsorbent layer can provide a fluid flow path that remains unobstructed, particularly when the absorbent layer is near saturation.

[0044] like Figure 2B, an orifice or through-hole 228 can be provided in the absorbent layer 221 below the aperture 227, such that the aperture is directly connected to the transfer layer 226. This allows negative pressure to be applied to the fluid connector 110 to communicate with the transfer layer 226 without passing through the absorbent layer 221. This ensures that the negative pressure applied to the wound site is not inhibited by the absorbent layer as it absorbs wound exudate. In other embodiments, no orifice may be provided in the absorbent layer 221, or alternatively, a plurality of orifices located below the aperture 227 may be provided. In other alternative embodiments, an additional layer (e.g., another transfer layer or a shielding layer as described in International Patent Publication WO2014020440, which is incorporated herein by reference in its entirety) may be provided above the absorbent layer 221 and below the backing layer 220.

[0045] In some embodiments, the backing layer 220 is impermeable to gases but permeable to water vapor and may extend across the width of the wound dressing 100. The backing layer 220, for example, may be a polyurethane film (e.g., Elastollan SP9109) with a pressure-sensitive adhesive on one side. This layer is impermeable to gases and thus functions to cover the wound and seal the wound cavity over which the wound dressing is placed. In this way, an effective chamber is created between the backing layer 220 and the wound site, allowing negative pressure to build up at the wound site. For example, the backing layer 220 may be sealed to the wound contact layer 222 in a border region around the circumference of the dressing using adhesive or welding techniques, ensuring that no air is drawn through the border region. The backing layer 220 protects the wound from external bacterial contamination (a bacterial barrier) and allows liquid from wound exudate to pass through the layer and evaporate from the outer surface of the film. The backing layer 220 may comprise two layers: a polyurethane film and an adhesive pattern applied to the film. The polyurethane film is permeable to moisture vapor and may be made of a material that increases its water permeability 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 can be up to about ten times greater than the moisture permeability of the dry backing layer.

[0046] The absorbent layer 221 may be larger in area than the transmission layer 226 so 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 helps exudate to be absorbed into the absorbent layer more quickly. Furthermore, the outer channel ensures that no liquid can pool around the perimeter of the wound cavity, which could otherwise seep through the seal around the perimeter of the dressing and cause a leak. Figures 2A-2B As shown in , the absorbent layer 221 can define a perimeter that is smaller than the perimeter of the backing layer 220 such that a demarcation or border region is defined between an edge of the absorbent layer 221 and an edge of the backing layer 220 .

[0047] like Figure 2BAs shown in FIG, one embodiment of a wound dressing 100 includes an orifice 228 in an absorbent layer 221 located beneath a fluid connector 110. In use, for example, when negative pressure is applied to the dressing 100, the wound-facing portion of the fluid connector can thereby contact the transmission layer 226, which can thereby facilitate transmission of the negative pressure to the wound site even when the absorbent layer 221 is filled with wound fluid. Some embodiments can have a backing layer 220 at least partially adhered to the transmission layer 226. In some embodiments, the orifice 228 is at least 1-2 mm larger than the diameter of the wound-facing portion or aperture 227 of the fluid connector 110.

[0048] For example, in an embodiment having a single fluid connector 110 and through hole, it may be preferred that the fluid connector 110 and through hole be located such as Figure 2A . This position can allow the dressing 100 to be positioned on the patient so that the fluid connector 110 is elevated relative to the rest of the dressing 100. So positioned, the fluid connector 110 and filter 214 are less likely to come into contact with wound fluid, which could prematurely occlude the filter 214 and thereby impair the delivery of negative pressure to the wound site.

[0049] Turning now to the fluid connector 110, some embodiments include a sealing surface 216, a bridge 211 having a proximal end 130 and a distal end 140 (corresponding to Figures 1A-1B), and a filter 214. Sealing surface 216 can form the applicator described above, which seals to the top surface of the wound dressing. In some embodiments, the bottom layer of fluid connector 110 can include sealing surface 216. Fluid connector 110 can also include an upper surface vertically spaced from sealing surface 216. In some embodiments, sealing surface 216 is defined by a separate upper layer of the fluid connector. In other embodiments, the upper and lower surfaces can be formed from the same piece of material. In some embodiments, sealing surface 216 can include at least one opening 229 therein for communication with the wound dressing. In some embodiments, filter 214 can be positioned through opening 229 in sealing surface and can span the entire opening 229. Sealing surface 216 can be configured to seal the fluid connector to the cover layer of the wound dressing and can include an adhesive or weld. In some embodiments, sealing surface 216 can be positioned over an aperture in the cover layer. In other embodiments, the sealing surface 216 can be positioned over the apertures in the cover layer and the apertures in the absorbent layer 220 to allow the fluid connector 110 to provide air flow through the transmission layer 226. In some embodiments, the bridge 211 can include a first fluid passage 212 in communication with a source of negative pressure, the first fluid passage 212 comprising a porous material, such as a 3D knit material, which can be the same as or different from the porous layer 226 described above. The bridge 211 can be encapsulated by at least one flexible membrane layer 208, 210 having a proximal end and a distal end, and configured to surround the first fluid passage 212, the distal end of the flexible membrane being connected to the sealing surface 216. The filter 214 is configured to substantially prevent wound exudate from entering the bridge.

[0050] Some embodiments may also include an optional second fluid passageway positioned above the first fluid passageway 212. For example, some embodiments may provide an air leak that may be positioned at a proximal end of the top layer configured to provide an air path into the first flow passageway 212 and the dressing 100, similar to the suction adapter described in U.S. Patent No. 8,801,685, which is incorporated herein by reference in its entirety.

[0051] In some embodiments, the fluid pathway 212 is constructed of a compliant material that is flexible and allows fluid to pass therethrough if the spacer is kinked or folded. Suitable materials for the fluid pathway 212 include, but are not limited to, foams, including open-cell foams such as polyethylene or polyurethane foams, meshes, 3D knitted fabrics, nonwoven materials, and fluid channels. In some embodiments, the fluid pathway 212 may be constructed of materials similar to those described above with respect to the transfer layer 226. Advantageously, such materials used in the fluid pathway 212 not only allow for greater patient comfort, but also provide greater kink resistance, such that the fluid pathway 212 can still transfer fluid from the wound toward the negative pressure source when kinked or bent.

[0052] In some embodiments, fluid pathway 212 may comprise a wicking fabric, such as a knitted or woven spacer fabric (e.g., knitted polyester 3D fabric, Baltex 7970®, or Gehring 879®) or a nonwoven fabric. These materials may be selected to channel wound exudate away from the wound and to deliver negative pressure or exhaust air to the wound site, and may also impart a degree of kink or occlusion resistance to fluid pathway 212. In some embodiments, the wicking fabric may have a three-dimensional structure, which may, in some cases, aid in wicking fluid or delivering negative pressure. In certain embodiments comprising a wicking fabric, the material remains open and is capable of delivering negative pressure to the wound area at typical pressures used in negative pressure therapy (e.g., between 40 and 150 mmHg). In some embodiments, the wicking fabric may comprise several layers of material stacked or laminated upon one another, which may, in some cases, serve to prevent fluid pathway 212 from collapsing under the application of negative pressure. In other embodiments, the wicking fabric used in the fluid pathway 212 may be between 1.5 mm and 6 mm; for example, the wicking fabric may be 3 mm to 6 mm thick and may include one or several separate layers of wicking fabric. In other embodiments, the fluid pathway 212 may be between 1.2-3 mm thick, for example, thicker than 1.5 mm. Some embodiments (e.g., a suction adapter used in conjunction with a dressing that retains liquids such as wound exudate) may utilize a hydrophobic layer in the fluid pathway 212, and only gas may travel through the fluid pathway 212. Furthermore, and as previously described, the materials used in the system may be conformable and soft, which may help avoid pressure ulcers and other complications that may result from the wound treatment system pressing against the patient's skin.

[0053] In some embodiments, the filter element 214 is impermeable to liquids but permeable to gases and is provided to act as a liquid barrier and ensure that no liquid can escape from the wound dressing 100. The filter element 214 can also function as a bacterial barrier. Typically, the pore size is 0.2 μm. Suitable filter materials for the filter element 214 include 0.2 μm Gore™ expanded PTFE, PALL Versapore™ 200R, and Donaldson™ TX6628 from the MMT line. Larger pore sizes can also be used, but these may require a secondary filter layer to ensure complete bioburden containment. Because wound fluids contain liquids, it is preferred, but not required, to use an oleophobic filter membrane, such as 1.0 μm MMT-332, before the 0.2 μm MMT-323. This prevents liquids from blocking the hydrophobic filter. The filter element can be attached or sealed to a cover membrane over the port or aperture. For example, the filter element 214 may be molded into the fluid connector 110, or may be adhered to one or both of the top of the cover layer and the bottom of the suction adapter 110 using an adhesive (such as, but not limited to, a UV-cured adhesive).

[0054] It will be appreciated that other types of materials can be used for the filter element 214. More generally, a microporous membrane can be used. This is a flat sheet of polymeric material containing billions of micropores. Depending on the membrane selected, these pores can range in size from 0.01 to greater than 10 microns. Microporous membranes are available in both hydrophilic (water-repelling) and hydrophobic (water-repelling) forms. In some embodiments, the filter element 214 comprises a support layer and an acrylic copolymer membrane formed on the support layer. In some embodiments, the wound dressing 100 utilizes a microporous hydrophobic membrane (MHM). A variety of polymers can be used to form MHMs. For example, MHMs can be formed from one or more of PTFE, polypropylene, PVDF, and acrylic copolymers. All of these polymer options can be treated to obtain specific surface characteristics, which can be either hydrophobic or oleophobic. Consequently, they will repel liquids with low surface tension, such as multivitamin infusions, lipids, surfactants, oils, and organic solvents.

[0055] MHMs block liquids while allowing air to flow through the membrane. They also act as highly effective air filters, eliminating potentially infectious aerosols or particles. Single-piece MHMs are well-known alternatives to mechanical valves or vents. Incorporating MHMs can therefore reduce product assembly costs, improving patient profitability and cost / benefit ratios.

[0056] Filter element 214 may also include an odor-absorbing material, such as activated carbon, carbon fiber cloth, or VitecCarbotec-RT Q2003073 foam. For example, the odor-absorbing material may form a layer within filter element 214 or may be sandwiched between the microporous, hydrophobic membranes of the filter element. Filter element 214 thus allows gases to escape through its pores. However, dressings contain liquids, particles, and pathogens.

[0057] Similar to the wound dressing embodiments described above, some wound dressings include a perforated wound contact layer with a silicone adhesive on the skin-contacting surface and an acrylic adhesive on the back surface. A transfer layer or 3D spacer fabric pad is positioned above this boundary layer. An absorbent layer is positioned above the transfer layer. The absorbent layer may comprise a superabsorbent nonwoven (NW) pad. The absorbent layer may extend approximately 5 mm beyond the transfer layer at its perimeter. The absorbent layer may have an orifice or through-hole toward one end. The orifice may be approximately 10 mm in diameter. A backing layer is positioned over the transfer layer and absorbent layer. The backing layer may be a high moisture vapor transmission rate (MVTR) film coated with a pattern of acrylic adhesive. The high MVTR film and wound contact layer encapsulate the transfer layer and absorbent layer, creating a perimeter boundary of approximately 20 mm. The backing layer may have a 10 mm orifice overlying the orifice in the absorbent layer. A fluid connector may be attached over the orifice and include a liquid-impermeable, breathable semipermeable membrane (SPM) overlying the orifice.

[0058] Go to Figure 2C In some embodiments, other wound types (e.g., larger abdominal wounds) may be treated with negative pressure using a negative pressure therapy system 101 as schematically shown herein. In some embodiments, a wound site 106 (shown here as an abdominal wound site) may benefit from negative pressure therapy. Such an abdominal wound site may be the result of an accident or surgical intervention, for example. In some cases, medical conditions such as abdominal compartment syndrome, abdominal hypertension, sepsis, or fluid edema may require abdominal decompression through a surgical incision in the abdominal wall to expose the peritoneal cavity, after which the opening may need to remain open and accessible until the condition resolves. Other conditions may also require that the opening (particularly in the abdominal cavity) remain open, for example, if multiple surgical procedures are required (which may be prone to trauma), or if there are signs of a clinical condition such as peritonitis or necrotizing fasciitis.

[0059] In the presence of a wound, particularly in the abdomen, there is a need to manage potential complications associated with exposure of organs and the peritoneal cavity, regardless of whether the wound is left open or closed. Targeted treatment (e.g., using negative pressure) can be used to minimize the risk of infection while promoting tissue vitality and removing harmful substances from the wound site. It has been found that applying reduced pressure or negative pressure to the wound site generally promotes faster healing, increases blood flow, reduces bacterial load, increases the rate of granulation tissue formation, stimulates fibroblast proliferation, stimulates endothelial cell proliferation, closes chronic open wounds, inhibits burn infiltration, or enhances flap and graft attachment, among other things. Wounds that have also been reported to respond positively to treatment with the application of negative pressure include infected open wounds, decubitus ulcers, open incisions, partial thickness burns, and various lesions of attached flaps or grafts. Therefore, applying negative pressure to the wound site 106 may be beneficial to the patient.

[0060] Thus, certain embodiments provide for placing a wound contact layer 105 over the wound site 106. The wound contact layer may also be referred to as an organ protection layer or a tissue protection layer. In some embodiments, the wound contact layer 105 may be a thin, flexible material that does not adhere tightly to the wound site or exposed internal organs. For example, polymers such as polyurethane, polyethylene, polytetrafluoroethylene, or blends thereof may be used. In one embodiment, the wound contact layer is permeable. For example, the wound contact layer 105 may be provided with openings, such as holes, slits, or channels, to allow fluid to be removed from the wound site 106 or to transmit negative pressure to the wound site 106. Additional embodiments of the wound contact layer 105 are described in further detail below.

[0061] Certain embodiments of the negative pressure therapy system 101 may also utilize a porous wound filler 103, which may be positioned above the wound contact layer 105. This pad 103 may be constructed of a porous material (e.g., foam) that is soft, resilient, and generally conforms to the wound site 106. Such foams may include open-cell and reticulated foams made from, for example, polymers. Suitable foams include those composed of, for example, polyurethane, silicone, and polyvinyl alcohol. In some embodiments, the pad 103 can direct wound exudate and other fluids through it when negative pressure is applied to the wound. Some pads 103 may include preformed channels or openings for this purpose. In certain embodiments, the pad 103 may have a thickness between approximately 1 inch and approximately 2 inches. The pad may also have a length between approximately 16 and 17 inches and a width between approximately 11 and 12 inches. In other embodiments, the thickness, width, or length may have other suitable values. Other embodiments of wound fillers that may be used as an alternative to or in addition to the pad 103 are discussed in further detail below.

[0062] In some embodiments, the drape 107 is used to seal the wound site 106. The drape 107 can be at least partially liquid impermeable so that at least partial negative pressure can be maintained at the wound site. Suitable materials for the drape 107 include, but are not limited to, synthetic polymeric materials that do not significantly absorb aqueous fluids, including polyolefins such as polyethylene and polypropylene, polyurethanes, polysiloxanes, polyamides, polyesters and other copolymers and mixtures thereof. The materials used in the drape can be hydrophobic or hydrophilic. Examples of suitable materials include Transeal® available from DeRoyal and OpSite® available from Smith & Nephew. To aid in patient comfort and avoid skin maceration, the drape is at least partially breathable in some embodiments so that water vapor can pass through without being collected under the dressing. An adhesive layer can be provided on at least a portion of the underside of the drape 107 to secure the drape to the patient's skin, but some embodiments may alternatively use a separate adhesive or adhesive tape. Optionally, a release layer may be disposed over the adhesive layer to protect it prior to use and to facilitate handling of the drape 107; in some embodiments, the release layer may be composed of multiple sections.

[0063] The negative pressure system 101 can be connected to a negative pressure source, such as a pump 114. An example of a suitable pump is the Renasys EZ pump available from Smith & Nephew. The drape 107 can be connected to the negative pressure source 114 via a conduit 112. The conduit 112 can be connected to a port 113 located above the hole 109 in the drape 107, or the conduit 112 can be connected directly through the hole 109 without using a port. In another alternative, the conduit can pass from under the drape and extend from the side of the drape. U.S. Patent No. 7,524,315 discloses other similar aspects of the negative pressure system, and the entire contents of which are incorporated herein by reference and should be considered a part of this specification.

[0064] In many applications, a container or other storage unit 115 may be interposed between the negative pressure source 114 and the conduit 112 to allow wound exudate and other fluids removed from the wound site to be stored without entering the negative pressure source. Certain types of negative pressure sources, such as peristaltic pumps, may also allow the container 115 to be placed after the pump 114. Some embodiments may also utilize a filter to prevent fluid, aerosols, and other microbial contaminants from leaving the container 115 and / or entering the negative pressure source 114. Additional embodiments may also include a shutoff valve or a closed hydrophobic or oleophobic filter in the container to prevent overflow; other embodiments may include a sensing device, such as a capacitive sensor or other level detector, to stop or shut off the negative pressure source if the liquid level in the container approaches capacity. In some embodiments, an odor filter, such as an activated charcoal canister, is provided at the pump exhaust.

[0065] Figure 2D Various embodiments of wound dressings that can be used to heal wounds without negative pressure are shown. Figure 2D As shown in the dressing of the reference, the wound dressing can have a similar Figures 1A-1B and multiple layers of dressings described in 2A-2B, except Figure 2D The dressing does not include ports or fluid connectors. Figure 2D The wound dressing may include a cover layer and a wound contact layer as described herein. The wound dressing may include various layers located between the wound contact layer and the cover layer. For example, the dressing may include one or more absorbent layers or one or more transfer layers, as described herein with reference to Figures 1A-1BIn addition, some embodiments described herein related to wound treatment including wound dressings may also be used in combination with 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 is incorporated herein by reference in its entirety, including further details regarding embodiments of wound dressings, wound dressing components and principles, and materials for wound dressings.

[0066] Sensor-enabled dressings Wound dressings containing multiple sensors or sensors separate from the wound dressing can be used to monitor wound characteristics as the wound heals or identify one or more risk factors or conditions that may predispose the wound to compromise. Collecting data from both well-healing and poorly healing wounds can provide useful insights for identifying measurements or measurands that indicate one or more conditions, including whether the wound is on a healing trajectory, whether the dressing needs to be adjusted, whether treatment parameters need to be adjusted, and the like. This can enable one or more adjustments. For example, operating parameters of a negative pressure wound therapy device (e.g., pressure level, treatment intensity, treatment duration, etc.) can be adjusted. One or more sensors can be used to measure various physiological parameters, as described herein.

[0067] Many sensor technologies can be used in a wound dressing or one or more components forming part of an overall wound dressing device. Figure 3A and 3H As shown in , in some embodiments, a subset of sensors may be incorporated onto or into a wound contact layer, which may be a perforated wound contact layer, such as Figure 3H As shown in . Figure 3A and 3H The wound contact layer in FIG is shown as having a square shape, but it will be appreciated that the wound contact layer may have other shapes, such as rectangular, circular, oval, etc. In some embodiments, the sensor-integrated wound contact layer may be provided as a separate layer of material that is placed over the wound area and then covered by a wound dressing device or a component of a wound dressing device, similar to the reference Figure 2C those described above (e.g., gauze, foam or other wound packing material, superabsorbent layer, drape, fully integrated dressing such as Pico or Allevyn Life dressing, etc.). In other embodiments, the sensor-integrated wound contact layer may be, e.g. Figures 1A-2B and a portion of a single unit dressing as described in 2D.

[0068] The sensor-integrated wound contact layer can be placed in contact with the wound and will allow fluid to pass through the contact layer while causing little or no damage to the tissue in the wound. The sensor-integrated wound contact layer can be made of a flexible material such as silicone and can contain an antimicrobial agent or other therapeutic agent known in the art. In some embodiments, the sensor-integrated wound contact layer can include an adhesive that adheres to wet or dry tissue. In some embodiments, one or more sensors, sensor packages, or sensor arrays can be incorporated into or encapsulated within other components of the wound dressing (e.g., the absorbent layer or spacer layer described above).

[0069] like Figure 3A and 3H As shown in , a subset of five sensors can be used, including sensors for: temperature (e.g., 25 thermistor sensors in a 5×5 array, ~20 mm spacing), pulse oximetry or SpO2 (e.g., 4 or 5 SpO2 sensors in a single line from the center of the wound contact layer to its edge, 10 mm spacing), optical properties of tissue, exudate, or foreign matter (e.g., 10 optical sensors in a 2×5 array, ~20 mm spacing; not all 5 sensors in each row of the array need to be aligned), pH (e.g., by measuring the color of a pH sensitive pad, optionally using an optical sensor that is the same color as the tissue), and conductivity (e.g., 9 conductive contacts in a 3×3 array, ~40 mm spacing). In some embodiments, SpO2 is an estimate of arterial oxygen saturation. As Figure 3A As shown in [ 1 ], in some embodiments, the SpO2 sensors can be arranged in a single line from the center or near the center of the wound contact layer to the edge of the wound contact layer. This line of SpO2 sensors can allow the sensors to be placed in the middle of the wound, at the edge or at the wound, or on intact skin to measure variations between various areas. In some embodiments, the wound contact layer or sensor array can be larger than the size of the wound to cover the entire surface area of ​​the wound as well as the surrounding intact skin. The larger size of the wound contact layer or sensor array and multiple sensors can provide more information about the wound area than if the sensors were placed only in the center of the wound or in only one area at a time. Other sensors can be used in addition or alternatively, such as pressure sensors, flow sensors, strain sensors, colorimetric sensors configured to measure biological or chemical compounds (e.g., dye-coated colorimetric sensors), etc. Colorimetric sensors can be used to measure odor, toxicity, etc. Any one or more of the sensors described herein can be placed or positioned to obtain measurements at any location in the wound or skin.

[0070] The sensors may be supported by or incorporated into a flexible or substantially flexible substrate, such as one or more flexible or substantially flexible printed circuits (FPCs), which may be formed from flexible polymers including polyamide, polyimide (PI), polyester, polyethylene naphthalate (PEN), polyetherimide (PEI), polyurethane, thermoplastic polyurethane (TPU), various fluoropolymers (FEP) and copolymers, or any other suitable material. Although the description may refer to one or more substantially flexible or substantially flexible printed circuits that may include circuit boards, other types of flexible or substantially flexible substrates may alternatively or additionally be used, such as one or more non-conductive materials or mesh or woven conductive fibers. For example, one or more wound dressing components, such as the wound contact layer, may include conductive or non-conductive materials. The substantially flexible or substantially flexible substrate may include single-sided, double-sided, or multi-layer circuits. In some embodiments, the sensor array may be incorporated into two layers of the flexible circuit. In some embodiments, the FPC may be a multi-layer flexible printed circuit. In some embodiments, these flexible printed circuits may be incorporated into any layer of the wound dressing. In some embodiments, the flexible circuit can be incorporated into the wound contact layer (e.g., positioned on or in the wound contact layer). For example, the flexible circuit can be incorporated into a wound contact layer similar to the reference Figure 2B and 2C The wound contact layer may have a cutout or slit that allows one or more sensors to protrude from the lower surface of the wound contact layer and directly contact the wound area.

[0071] In some embodiments, the sensor-integrated wound contact layer may include a first and a second wound contact layer, wherein the FPC is sandwiched between the two layers of wound contact layer material. The first wound contact layer has a lower surface intended to contact the wound and an upper surface intended to contact the FPC. The second wound contact layer has a lower surface intended to contact the FPC and an upper surface intended to contact the wound dressing or one or more components forming part of the entire wound dressing device. The upper surface of the first wound contact layer and the lower surface of the second wound contact layer can be attached together by the FPC sandwiched between the two layers.

[0072] In some embodiments, one or more sensors of the FPC may be completely encapsulated or covered by the wound contact layer to prevent contact with moisture or fluid in the wound. In some embodiments, the first wound contact layer may have a cutout or slit that allows one or more sensors to protrude from the lower surface and directly contact the wound area. For example, Figure 3HThe one or more SpO2 sensors shown in FIG are shown protruding from the bottom surface of the wound contact layer. In some embodiments, the SpO2 sensor or other sensors can be mounted directly on the lower surface of the first wound contact layer so as to be in direct contact with the wound. Some or all of the sensors and electrical or electronic components can be potted out of direct contact with the wound or encapsulated with a suitable material (e.g., a polymer and, for example, a silicone or epoxy-based polymer) (e.g., rendering it substantially waterproof or liquid-proof and biocompatible). Encapsulation with a polymer can prevent fluid ingress and leaching of chemicals from the components. In some embodiments, the wound contact layer material can seal the components to prevent water ingress and leaching of chemicals. One or more sensors and electrical or electronic components can be fully potted or embedded and configured for wireless communication to prevent contact with liquids.

[0073] In some embodiments, one or more sensors may be arranged or deployed in alternative or additional ways as follows. The sensors may be arranged in strips or strings. The sensors may be placed in or within a holder that can be inductively powered. The holder may also communicate with a control module or another processing device, as described herein. The sensors may be positioned or cast into the foam of a wound dressing or into another matrix configured to fill the wound. The sensors may be mounted to projections or protrusions of the foam (or other matrix) that fit within the wound. For example, the sensors may be mounted to protrusions of superabsorbent foam or another superabsorbent material and may extend into the wound when exposed to wound exudate. The sensors may be incorporated into a deployment material or system separate from the wound dressing. The sensors may be encapsulated or mounted to a wound dressing material or substrate, such as Durafiber or duraTouch. For example, the sensors may be sewn into a gauze or Durafiber dressing manufactured by Smith & Nephew. Custom three-dimensional molds may be cut or constructed for specific wound configurations or geometries to properly position the sensors. The sensor array, arrangement, or package can be rotationally symmetric or substantially rotationally symmetric, making it less susceptible to rotational misalignment. Sensors can be coated with a hydrophobic or hydrophilic material to prevent exudate from coating or depositing on the sensor and adversely affecting measurements. For example, an optical sensor can be coated with a hydrophobic material to repel liquids for measurement. As another example, a pH sensor can be coated with a hydrophilic material to absorb exudate for measurement. Sensors can include one or more flushing channels or flow paths to flush the sensor. For example, this can be used to remove exudate or material from one or more regions of interest to improve measurement accuracy. Additionally or alternatively, one or more flow paths can be used to direct exudate to specific locations (e.g., sensors or sensor groups) to improve measurement accuracy. For example, this can result in a greater signal-to-noise ratio or isolate specific sensors or sensor groups from vulnerable areas of a wound.

[0074] In certain embodiments, the sensor array, arrangement, or package may include one or more alignment marks, edges, or features that can be aligned or co-registered with one or more marks, edges, tags, or anatomical features to ensure correct placement. For example, this can improve alignment of the sensor with the wound or the skin or tissue surrounding the wound. In some cases, the sensor array, arrangement, or package can be aligned with an electromagnetic tag placed on or near the wound, which can help correctly position and rotate the sensor relative to the tag and the wound. Images of the sensor array, arrangement, or package after placement can be taken to analyze the sensor orientation. This information can be used to assess sensor positioning or facilitate correct positioning when changing sensors (for example, when discarding a dressing). One or more sensor strings or strips can be used to limit orientation errors. Alignment rings can be removably or semi-permanently attached or printed around the wound to allow for precise positioning when changing wound dressings. In cases where the sensor array, arrangement, or package is deformable or substantially deformable, individual sensors can be configured to register their position relative to other sensors to analyze positioning or alignment.

[0075] One or more pressure monitors (e.g., one or more strain gauges) can be included to monitor whether the wound dressing is too tight or too loose. Feedback from the one or more pressure monitors can be used to indicate whether the dressing needs to be tightened or loosened. This can be advantageously used for compression bandaging.

[0076] In some embodiments, collecting and processing wound-related information can use three components, including a sensor array, a control module, and processing software. These components are described in more detail herein.

[0077] As mentioned above, Figure 3A The sensor array may include a temperature sensor, a conductivity sensor, an optical sensor and an SpO2 sensor. The flexible sensor array printed circuit 300 includes a sensor array portion 301, a tail portion 302 and a connector pad end portion 303, such as Figure 3B As shown in . The sensor array portion 301 may include sensors and associated circuitry. The sensor array printed circuit 300 may include a long tail portion 302 extending from the sensor array portion 301. The connector pad end portion 303 can be electrically or electronically connected to a control module or other processing unit to receive data from the sensor array circuitry. The long tail portion 302 may allow the control module to be placed away from the wound and in a more convenient location. Figure 3B An overall view of one of the sensor array printed circuits 300 is shown in FIG.

[0078] In certain embodiments, a controller (e.g., a microprocessor) can be mounted on the dressing and connected to the sensor. Such a mounted controller can communicate with the control module via a simple connection, such as a 3- or 4-wire connection (or fewer or more wires), to reduce the burden associated with connecting to external components. For example, the long tail 302 can include a 3- or 4-wire connection. In some embodiments, the mounted controller can communicate wirelessly.

[0079] Figures 3C-3F An embodiment of an FPC having four different sensor array geometries is shown. The four different sensor array geometries shown are implemented in a flexible circuit. Although Figures 3C-3F Four different sensor array formats and configurations are shown, but Figure 3D The design shown in also shows the connector pad end 303. However, it is also possible to create a Figure 3C 、 3E and 3F are designed to allow these FPCs to communicate with control modules or other processing units. Figures 3C-3F Four different sensor array geometries in sensor array section 301 are shown.

[0080] Figure 3G According to some embodiments, the Figure 3D The sensor array portion 301 of the sensor array design is shown in FIG. Figures 3A-3G In embodiments of the present invention, it will be appreciated that the sensor array portion 301 includes a plurality of portions that extend around the perimeter of a wound dressing component (e.g., a wound contact layer) or extend inwardly from an outer edge of the wound dressing component. For example, the illustrated embodiment includes a plurality of linear extensions that may be parallel to the edge of the wound dressing component and, in some embodiments, follow the entire perimeter of the wound dressing component. In some embodiments, the sensor array portion may include a first plurality of parallel linear extensions that are perpendicular to a second plurality of parallel linear extensions. These linear extensions may also have different lengths and may extend inwardly to different locations within the interior of the wound dressing component. In some embodiments, the sensor array portion does not cover the entire wound dressing component such that gaps are formed between portions of the sensor array. Figure 3A This allows some, and possibly most, wound dressing components to not be covered by the sensor array. Figure 3A and 3H As shown with a perforated wound contact layer, the sensor array portion 301 may not block most of the perforations in the wound contact layer. In some embodiments, the sensor array may also be perforated or shaped to match the perforations in the wound contact layer, thereby minimizing obstruction of fluid flow by the perforations.

[0081] The electrical or electronic connections of the sensor array may vary depending on the various sensors and sensor array designs used. In some embodiments, Figures 3C-3F As shown in the figure, a total of 79 connections can be used to connect components of the sensor array. For example, a subset of sensors in the sensor array or all of them can be connected to each other. The sensor array can be terminated in two parallel 40-way 0.5mm pitch flat flexible cable (FFC) contact surfaces, with terminals on the top surface designed to connect to an FFC connector such as the Molex 54104-4031.

[0082] In some embodiments, a temperature sensor, conductivity sensor, SpO2 sensor, or optical, ultraviolet (UV), infrared (IR), or other types of visible or invisible light sensors can be used on the sensor array to provide information related to the condition of the wound. Optical, ultraviolet (UV), infrared (IR), or other types of visible or invisible light or other electromagnetic spectrum sensors can provide spectral measurements of the wound. The sensor array and individual sensors can help clinicians monitor wound healing. One or more sensors can operate individually or in coordination with each other to provide data related to the wound and its healing characteristics.

[0083] The temperature sensor or thermometer can use a thermocouple or thermistor to measure temperature. The temperature sensor can be used to measure or track the temperature of the thermal environment below the wound or within the wound dressing. The temperature sensor can be calibrated, and the data obtained from the sensor can be processed to provide information about the wound environment. In some embodiments, a second temperature sensor that measures the temperature of another area different from the area of ​​interest or an ambient sensor that measures the ambient air temperature can also be used to help eliminate problems associated with ambient temperature variations, such as compensating for changes in heat flux away from the area of ​​interest or compensating for physiological effects associated with ambient temperature variations.

[0084] Using light sensors with integrated or independent illumination sources (e.g., optical, ultraviolet (UV), infrared (IR), or other types of visible or invisible light sensors), optical sensors can be used to measure wound or skin parameters, such as the appearance of one or more of wound tissue, exudate, the wound site, or the skin surrounding the wound. In some embodiments, the sensor (along with the independent illumination source) can be pressed against the skin so that light penetrates into the tissue and reflects the tissue's own spectral signature. In some embodiments, the sensor (along with the independent illumination source) can be positioned remotely from or away from the imaging area. Light guides, such as silicone or optical fibers, can be used to deliver light to the imaging area. Optical sensors can measure one or more components (e.g., tissue, blood vessels, etc.) at various depths at or below the surface. Diffusion of one or more wavelengths of light can be used to obtain measurements at various depths (e.g., to achieve depth accuracy or selectivity). Measurements at various depths can be performed by varying the spacing between the light source and detector. Optical coherence tomography can be used to obtain depth information. Confocal techniques can be used to achieve depth accuracy or selectivity. Optical sensors can be used to measure the gloss or polarization of the wound, which can be used to measure exudate levels, the presence of biofilm, and more. One or more optical features (e.g., waveguides, lenses, or polarization features) can be incorporated into or beneath a wound dressing to aid in measurements such as depth measurement. For example, one or more polarization features can be incorporated into or beneath a biocompatible dressing layer to enable or enhance polarization measurements, which can be used for depth measurement or blood perfusion or oxygen saturation measurements.

[0085] In some embodiments, one or more optical fingerprint sensors may be used. Such sensors can be used as spectroscopic devices and configured to measure the presence or absence of a certain spectral response. The response can be linear or nonlinear (fluorescence). For example, fluorescence measurements can include exudate measurements, tissue fluorescence (e.g., via contact measurement), or bacterial fluorescence. The presence or absence of one or more compounds, such as volatile organic compounds (VOCs), can be identified from the spectral response. The presence of a compound can indicate metabolic, biological, or chemical activity that may be associated with, for example, infection or normal healing processes. The presence or absence of specific molecules can be identified from the spectral response. For example, the presence of ozone (which may benefit wound healing) can be identified in the spectral region from approximately 220 nm to approximately 330 nm. Infrared spectral measurements can be used to identify the presence of carboxylic acids, such as butyric acid, that may be associated with proteins. In certain embodiments, one or more biomarkers or dyes can be used to enhance the spectral visibility or response of one or more components of interest.

[0086] In some embodiments, one or more light sources or detectors can be positioned outside the wound. The wound can be illuminated or light can be detected through the tissue. Transillumination can be used to identify the presence or absence of an abnormality.

[0087] In some cases, one or more electronic nose (or e-nose) sensors may be used to detect the presence of one or more VOCs.

[0088] Light propagation in tissue can be governed by two main phenomena: scattering and attenuation. With regard to attenuation, as light passes through tissue, its intensity may be lost due to absorption by the tissue's various components. Blue light tends to be severely attenuated, while light at the red end of the spectrum tends to be least attenuated.

[0089] The scattering process can be more complex and may have various "regions" that must be considered. The first aspect of scattering is based on the size of the scattering center compared to the wavelength of the incident light. If the scattering center is much smaller than the wavelength of the light, Rayleigh scattering can be assumed. If the scattering center is around the wavelength of the light, the more detailed Mie scattering formula must be considered. Another factor involved in the scattered light is the distance between the input and output of the scattering medium. If the mean free path of light (the distance between scattering events) is much greater than the distance traveled, ballistic photon transport is assumed. In the case of tissue, scattering events are approximately 100 microns apart, so a path distance of 1 mm will effectively randomize the photon direction, and the system will enter the diffuse region.

[0090] Figure 3J shows how far light can travel through the skin before its intensity decays by a factor of 1 / e (which is approximately 37% of its original intensity) according to some embodiments. The intensity loss is an exponential function (Beer-Lambert law) given by: 𝐼(igh)=𝐼0𝑒−𝜇(λ) where 𝜇 is the value of the penetration depth. This exponential decrease in intensity is why tissue appears red when illuminated; almost all light traveling in and out of the tissue will be in the red end of the spectrum. This can be thought of as a filter that changes with distance; as the light source moves further away, the spectrum reaching the detector will change accordingly. Figure 3J and 3K The pattern is a combination of factors such as scattering and attenuation of light entering the tissue. Figure 3J The intensity loss of light entering the tissue is shown. Figure 3K The response of an optical detector according to some embodiments is shown.

[0091] Suitable light sources, such as ultra-bright light emitting diodes (LEDs), optical detectors, or polyester optical filters, can be used as components of optical sensors to measure optical properties of tissue, exudate, or foreign matter (e.g., for tissue color differentiation). For example, since surface color can be measured from reflected light, color can be measured from light that first passes through the tissue for a given geometry. This can include color sensing of diffusely scattered light from a light source (e.g., white, RGB, IR LED, etc.) in contact with the wound or skin. In some embodiments, the light source can be used with a nearby optical detector to detect light that has diffused through the tissue. The optical sensor can image with diffuse internal light or surface reflected light. A suitable optical detector, such as a photodiode, can be used. For example, the optical detector can have a red, green, blue, clear (RGBC) spectral response (or sensitivity ratio across channels), such as Figure 3Q In some cases, the Rhom BH1745NUC color sensor can be used.

[0092] Additionally, optical sensors can be used to measure autofluorescence. Autofluorescence is used because tissue absorbs light at one wavelength and emits light at another. Furthermore, dead tissue may not autofluoresce, and thus can be a very strong indicator of tissue health. Because blue light (or even UV light) has such a short penetration depth, for example, UV light with a nearby red-sensitive photodiode (or some other wavelength-shifted band) can be very useful as a binary test for healthy tissue, as it will autofluoresce at a very specific wavelength.

[0093] Conductivity or impedance sensors can be used to determine the difference between living and dead tissue or to indicate impedance changes caused by opening a wound in diseased tissue. Conductivity sensors can include Ag / AgCl electrodes and an impedance analyzer. Conductivity sensors can be used to measure impedance changes in a wound growth area by measuring the impedance of the surrounding tissue / area. In some embodiments, a sensor array can utilize conductivity sensors to measure changes in conductivity at peripheral electrodes due to changes in wound size or shape. For example, wound size can be inferred using tomographic reconstruction or techniques by using conductivity sensors or electrodes at varying spacings. Voltage or current probes can be used to apply voltage or current stimulation to determine or test a patient's neural responses or promote wound healing. In some embodiments, conductivity sensors can be used within or around the wound bed. Conductivity measurements can be used to detect dressing adhesion failure. Conductivity can be measured by creating a conductive path through a biocompatible layer (e.g., of a wound dressing) or through a biocompatible gel layer (e.g., a conductive gel layer) or saline solution to contact the wound. Measurements can be made within a frequency range of approximately 2.5 kHz to approximately 60 kHz. This can be similar to using a large patch clamp measurement. Alternatively or additionally, conductivity can be measured using capacitance or capacitive coupling methods without making direct contact with the tissue (e.g., using non-contact electrodes). For example, transmission in the frequency range of about 30 kHz to about 70 kHz can be used. Conductivity can be measured using a three-point probe measurement or a four-point probe measurement. The conductivity of one or more of the wound tissue or exudate can be measured, which can be used to infer cell or tissue health. The conductivity of the peri-wound area (e.g., the skin or tissue surrounding the wound) can be measured. The conductivity sensor can be retractable to move in and out as needed. The conductivity sensor can include a thin or microprobe with a conductive tip and an insulated shaft that extends into the wound. The conductivity sensor can be a suspended probe beneath the wound contact layer, which contacts the wound. The conductivity sensor can include dry contact electrodes. The conductivity sensor can include electrodes configured to ensure or promote biocompatibility, such as gold, silver, platinum, or carbon electrodes.

[0094] In some embodiments, a pH-varying pad can be used as a pH sensor. A spectrometer and a broadband white light source or RGB LED can be used to measure the spectral response of the pH dye. Illumination and imaging can be provided on the surface of the wound dressing in contact with the wound and on the same side as the fluid application (the bottom surface). Alternatively, in some embodiments, the illumination and imaging source can be located on the surface of the wound dressing opposite the bottom surface and away from the fluid application, or on the top surface of the dressing or wound contact layer. In some embodiments, the pH sensor is an optical measurement device that spectrally measures two or three (or fewer or more) wavelengths of light when reflected from a colorimetric substance. A pH-varying foam can be included or integrated into the wound dressing. The foam can alter the spectral absorption of light depending on the environment (e.g., depending on the content or composition of wound exudate). Alternatively or additionally, a pad or feature that changes color due to changes in environmental pH can be utilized. Such a pad can be optically measured and evaluated to determine the pH level. In some cases, the pH sensor can include an exudate guidance system (e.g., a flow path) that allows exudate to flow through the pH-sensitive region of the sensor, which can improve detection accuracy. In some cases, the entire or substantially the entire dressing can be made pH-sensitive.

[0095] In some embodiments, one or more pulse oximetry sensors, such as SpO2 sensors, may be used. Such sensors can obtain multispectral optical measurements that can be used, for example, to measure one or more of the oxygenation level of the blood and pulsatile blood flow. The multispectral optical measurement sensor can determine time-resolved optical measurements. In some cases, pulse oximetry works by making time-resolved measurements of light absorption / transmission in tissue at two different optical wavelengths. When hemoglobin is oxygenated, its absorption spectrum changes relative to non-oxygenated blood. By taking measurements at two different wavelengths, a ratiometric metric of the oxygenation level of the blood can be obtained. For example, an SpO2 sensor can operate at a sampling rate of approximately 500 Hz and obtain dual-band red (R) and infrared (IR) measurements. According to some embodiments, measurements made using the SpO2 sensor in its original form are obtained at Figure 3L and Figure 3M Shown in. Figure 3M According to some embodiments Figure 3L A magnified view of the graph.

[0096] from Figure 3M The magnified graph clearly shows the waveform of pulsating blood flow. To extract SpO2, the value extracted from the data is the ratio between the height of a given pulse peak and its trough for each wavelength. Another ratio is then taken between these two values. Peak detection algorithms can be used to precisely locate peaks and troughs. Several data points can be taken for each case and averaged.

[0097] Once this ratio is calculated, the SpO2 level is empirically fitted using a "lookup table" that can be saved on the hardware. This value essentially depends on the absorption and scattering of human tissue at each wavelength, but the complexity of system modeling is avoided by using an empirical model.

[0098] The components in the sensor array can be connected via multiple connections. In some embodiments, temperature sensors (e.g., thermistors) can be arranged in groups of five. In some embodiments, multiple thermistors, each nominally 10 kΩ, can be used, with each group of five having a common ground. With five groups of thermistors, there are 30 connections in total. In some embodiments, there can be nine conductive terminals. Each conductive terminal requires one connection, providing a total of 9 connections. In some embodiments, up to 8 connections are used. For example, four connections can be made near the center of the sensor array (e.g., a 3 cm side square), and four connections can be made around the perimeter of the sensor array (e.g., a 9 cm side square). In some embodiments, an additional conductive layer can be included on the side of the conductive pad facing away from the tissue (on which connections are formed). The additional conductive layer can be separated from the conductive pad by a non-conductive layer. This can help direct electromagnetic propagation.

[0099] In some embodiments, there may be five SpO2 sensors. In some embodiments, each SpO2 sensor requires three connections, plus power and ground (which are covered separately), for a total of 15 connections. In some embodiments, there may be 10 optical, UV, IR, or other types of visible or invisible light sensors. Each such sensor may include a light source, such as an RGB LED or RGB photodiode. Each such sensor may require six connections, but five of these are common to all sensors, for a total of 15 connections. Power and ground are considered separately. In some embodiments, there may be five pH sensors. The pH sensor may be a color-changing disc and can be sensed using the optical, UV, IR, or other types of visible or invisible light sensors described above. Therefore, the pH sensor does not require additional connections. There may be three power rails and seven ground return signals, for a total of 10 common connections. In some embodiments, the sensor array can include 25 temperature sensors (e.g., thermistors Murata NCP15WB473E03RC), 9 conductivity terminals, 5 SpO2 sensors (e.g., ADPD144RI), 10 light sources (e.g., RGB LEDs such as KPTF-1616RGBC-13), 10 optical, UV, IR or other types of visible or invisible light sensors, 10 FETs, a printed circuit board (PCB), and components.

[0100] Figure 3H1 shows a flexible sensor array incorporated into a perforated wound contact layer according to some embodiments. Figure 3H As shown in , the PCB sensor array can be sandwiched between two membranes or wound contact layers. The wound contact layer can have perforations formed as slits or holes as described herein, which are small enough to help prevent tissue ingrowth into the wound dressing while allowing wound exudate to flow into the dressing. In some embodiments, the wound contact layer can have one or more slits that increase the flexibility of the wound contact layer with the integrated sensor array. In some embodiments, one of the wound contact layers can have additional cutouts to accommodate sensors so that they can directly contact the skin.

[0101] In some embodiments, the circuit is placed or printed onto one side of the substrate, and electronic components such as sensors are also placed on that side. The components and tracks can then be covered with one or more insulating or encapsulating layers on one or both sides of the substrate.

[0102] Figure 3N-3P A wound contact layer is shown that includes various arrangements of slits and holes to increase flexibility, allow sensors to directly access the wound, and facilitate fluid delivery through the wound contact layer. In some embodiments, the arrangement of holes and slits can allow sensors to enter the center of the wound, the edges of the wound, or intact skin. Figure 3N-3P Embodiments of wound contact layers with various slit arrangements and configurations are shown. Figure 3N An embodiment of a wound contact layer is shown comprising holes and curved slits extending radially from a large central hole.

[0103] Figure 3O A wound contact layer according to some embodiments is shown comprising holes and curved slits forming part of a circle and slits extending from the periphery of the circle to the centre of the wound contact layer.

[0104] Figure 3P A wound contact layer according to some embodiments is shown comprising a hole and slits extending radially from the large central hole towards the outer periphery of the wound contact layer.

[0105] A controller or control module can be used to interface with the sensor array. In some embodiments, the control module can contain a power source, such as a battery, and electronics for driving the sensors. The control module can also record data at appropriate intervals and allow the data to be transferred to an external computing device, such as a personal computer (PC). The control module can be customized to have various features, depending on the sensors used in the sensor array and the data collected by the sensors. In some embodiments, the control module can be comfortable and small enough to be worn continuously for several weeks. In some embodiments, the control module can be positioned near or on the wound dressing. In some embodiments, the control module can be positioned remotely from the wound dressing and accompanying sensor array. The control module can communicate with the sensor array and wound dressing via wires or through wireless communication, whether located on, near, or remote from the wound dressing. Wireless communication can be performed using one or more frequency bands of 125 kHz to 134 kHz, 13.56 MHz, 784 MHz, 856 MHz to 960 MHz, 868 MHz, 915 MHz, 2400 MHz to 2483.5 MHz, 3.6 GHz, 4.9 GHz, 5 GHz, or 5.9 GHz. In some embodiments, the control module can be adapted for use with different sensor arrays and can enable easy replacement of sensor arrays.

[0106] In some embodiments, the control module or electronics to which the sensor array is connected may include additional sensors. As another example, one or more additional sensors may detect blood sugar or glucose levels, hydration, or other physiological parameters (e.g., comorbidities, nutritional status, treatment, timescale, or general condition of the patient). One or more hydration sensors may perform inductance measurements by measuring alternating current (AC) on two pads and voltage on two other pads. Additionally or alternatively, skin elasticity may be correlated with nutritional status or hydration. Skin elasticity may be determined using ultrasound scanning with shallow penetration. An elastomeric electroactive polymer or another piezoelectric transducer may be used as the transducer or receiver for performing the ultrasound scan.

[0107] Data collected by one or more additional sensors can be used to correlate data received from the sensor array to test or improve accuracy. In some embodiments, changes in the output of one or more sensors in the sensor array that match the range of pulsatile blood flow (e.g., approximately 0.3 Hz to approximately 4 Hz) can be determined and correlated with data collected by the one or more additional sensors. This can be used to test or improve the accuracy of the sensor array.

[0108] In some embodiments, the control module may include a combination of various requirements and features, including but not limited to the features listed in Table 1 below.

[0109] Table 1. Optional features of the control module .

[0110] Figure 3I A block diagram of a control module according to some embodiments is shown. The block diagram of the control module includes a conductivity driver block 391 showing features of the conductivity driver. Block 392 shows features of a temperature sensor (e.g., a thermistor) interface, and block 393 shows features of an optical interface. The control module may include a controller or microprocessor having features similar to those shown in block 394. A real-time clock (RTC), status LEDs, a USB connector, serial flash memory, and a debug connector may be included as features of the control module, as shown. Figure 3I As shown in .

[0111] In some embodiments, the microprocessor may include one or more of the following features: a 2.4 GHz radio (integrated or external) or another frequency band disclosed herein, or any other suitable frequency; a Bluetooth software stack; an SPI interface; USB (or UART for external USB drivers); I2C; a 3-channel PWM; 32 GPIOs; or a 6-channel ADC. In some embodiments, due to packaging limitations, the device may include at least 48 I / O pins, or possibly more. The Bluetooth stack typically requires ~20kB of onboard flash memory, so at least 32kB may be required. In some embodiments, if complex data processing is considered, 64kB may be required. The processor core may be an ARM Cortex M4 or similar processor core. In some embodiments, the component may include an ST microprocessor (STM32L433LC or STM32F302R8), which may require an external radio, or an NXP Kinetis KW series with an integrated radio.

[0112] In some embodiments, the control module may include a memory component, where the amount of local storage depends on the sampling rate and resolution of the sensor. For example, an estimated data requirement of 256Mb (32MB) can be met using serial flash memory devices from many manufacturers (Micron, Spansion).

[0113] The control module can use one or more analog switches. In some embodiments, analog switches with good on-resistance and reasonable bandwidth can be used. For example, the Analog Devices ADG72 or the NXP NX3L4051HR can be used. In some cases, eight such switches may be needed.

[0114] The control module may include a power source, such as a battery. For example, a 300 mWh / day battery may be used. This translates to 2100 mWh over 7 days. This can be provided by a 10-day, non-rechargeable ER14250 (14.5 mm diameter x 25 mm) LiSOCl2 battery or a 7-day, rechargeable Li14500 (14.5 mm diameter x 500 mm) lithium-ion battery. In some embodiments, a power source separate from the control module may be used.

[0115] The control module can contain a real-time clock (RTC). The RTC can be selected from any RTC device with a crystal. The control module can also include various resistors, capacitors, connectors, a charge controller, and other power supplies.

[0116] The control module's PCB can be a 4-layer board, approximately 50mm x 20mm, or 25mm x 40mm. The type of PCB used depends largely on the connection requirements for the sensor array.

[0117] The housing of the control module may be a two-part molding with clip features to allow easy access to change the sensor array or battery.

[0118] Data collected by the sensor array can be passed through the control module and processed by host software. This software can be executed on a processing device. The processing device can be a PC, a tablet or tablet computer, a smartphone, or other computer capable of running host software (e.g., a custom computing device). The processing device executing the software can communicate with the control module via wires or wireless communication. In some embodiments, the software can be configured to provide access to data stored on the control module but not perform big data analytics (or edge computing) on ​​the data received from the sensors. The host software can include an interface to the control module via Bluetooth or USB. In some embodiments, the host software can read the status of the control module, download logged data from the control module, control the sampling rate uploaded to the control module, convert data from the control module into a format suitable for processing by a big data analytics engine, or upload data to the cloud for processing by the analytics engine.

[0119] The software can be developed for PCs (Windows / Linux), tablets, or smartphones (Android / iOS), or multiple platforms. In some embodiments, data collected by the sensor array can be transmitted to a remote computing device for processing. For example, the data can be uploaded to the internet or processed by the cloud. In some embodiments, when the connection between the sensor array and the control module is wired, the control module can communicate with the remote computing device (e.g., the cloud). In certain embodiments, when the connection between the sensor array and the control module is wireless, the sensor array can communicate directly with the remote computing device (e.g., the cloud) or use the control module to communicate with the remote computing device.

[0120] In some embodiments, the electronics, including one or more of the sensors or control modules, can be configured to be compatible or safe for x-ray, MRI, or other types of scans. The electronics can also be configured to be compatible or safe for external or implantable defibrillators. The electronics can include protection against radio frequency interference (RFI) or electromagnetic interference (EMI). For example, one or more EMI shields, which can be made of ferrite, copper, or other materials, can be used. Faraday cages, etc.

[0121] In certain embodiments, security measures may be implemented to prevent unauthorized access to measurement and other data. For example, certain communications or commands may need to be transmitted via a wired interface rather than wirelessly. Data encryption or modulation may also or alternatively be used. In certain embodiments, only device ID, clock time (which may not be correlated with a real-time clock), or raw data may be provided or identified over an unsecured interface. Without baseline patient identification or real-time clock information, which can be provided solely over a secure interface, such data is anonymous and meaningless.

[0122] In some embodiments, the negative pressure source (e.g., a pump) and some or all other components of the topical negative pressure system, such as a power source, sensors, connectors, user interface components (e.g., buttons, switches, speakers, screens, etc.), can be integrated with the wound dressing. In some embodiments, the components can be integrated beneath, within, on top of, or adjacent to the backing layer. In some embodiments, the wound dressing can include a second cover layer or a second filtration layer positioned above the layers of the wound dressing and any integrated components. The second cover layer can be the topmost layer of the dressing, or it can be a separate layer enclosing the integrated components of the topical negative pressure system.

[0123] As used herein, an upper layer, top layer or upper layer refers to the layer that is furthest from the surface of the skin or wound when the dressing is in use and positioned on a wound. Thus, a lower surface, lower layer, bottom layer or underlying layer refers to the layer that is closest to the surface of the skin or wound when the dressing is in use and positioned on a wound.

[0124] Use of NPWT system Figure 4A -D illustrates the use of a negative pressure therapy wound therapy system for treating a wound site on a patient, according to some embodiments. Figure 4A A wound site 400 is shown being cleaned and prepared for treatment. Here, the healthy skin surrounding the wound site 400 may be cleaned, and excess hair removed or shaved. If desired, the wound site 400 may also be rinsed with a sterile saline solution. Optionally, a skin protectant may be applied to the skin surrounding the wound site 400. If desired, a wound packing material, such as foam or gauze, may be placed in the wound site 400. This may be preferable if the wound site 400 is a deeper wound.

[0125] After the skin around the wound site 400 has dried, and now see Figure 4B The wound dressing 100 can be positioned and placed over the wound site 400. In some embodiments, the wound dressing 100 is placed over or in contact with the wound site 400 together with the wound contact layer. In some embodiments, an adhesive layer is provided on the lower surface of the wound contact layer, which in some cases may be protected by an optional release layer for removal before the wound dressing 100 is placed over the wound site 400. The dressing 100 can be positioned so that the fluid connector 110 is in an elevated position relative to the rest of the dressing 10 to prevent fluid from pooling around the port. In some embodiments, the dressing 100 is positioned so that the fluid connector 110 does not directly overlie the wound and is flush with or at a point above the wound. To facilitate adequate sealing of the TNP, the edges of the dressing 100 can be smooth to avoid wrinkling or folding.

[0126] See now Figure 4C The dressing 10 is connected to a pump 150. The pump 150 is configured to apply negative pressure to the wound site via the dressing 100, typically through a conduit. In some embodiments, and as described herein, a fluid connector 110 can be used to connect a conduit 190 from the pump to the dressing 100. When the fluid connector is adhered to the top layer of the wound dressing, a length of tubing can be coupled to the first end of the fluid connector, such that the tubing or conduit extends away from the fluid connector, parallel to the top of the dressing. In some embodiments, the conduit can comprise the fluid connector. It is expressly contemplated that the conduit can be a flexible bridge, a rigid tube, or any other device useful for conveying fluid. When negative pressure is applied by the pump 150, the dressing 100 can, in some embodiments, partially collapse, assuming a wrinkled configuration due to the evacuation of some or all of the air beneath the dressing 100. In some embodiments, the pump 150 can be configured to detect whether any leaks exist within the dressing 100, such as at the interface between the dressing 100 and the skin surrounding the wound site 400. If a leak is detected, the leak can be remedied before continuing treatment.

[0127] Go to Figure 4D An additional securing strip 410 may also be attached around the edge of the dressing 100. This securing strip 410 may be advantageous in some circumstances to provide an additional seal against the patient's skin around the wound site 400. For example, the securing strip 410 may provide an additional seal when the patient is more mobile. In some circumstances, particularly if the dressing 100 is placed in a hard-to-reach or contoured area, the securing strip 410 may be used before activating the pump 150.

[0128] Treatment of the wound site 400 can continue until the wound reaches the desired level of healing. In some embodiments, it may be desirable to replace the dressing 100 after a certain period of time has passed, or if the dressing is filled with wound fluid. During this change, the pump 150 can be maintained and only the dressing 100 can be replaced. For applications of wound dressings used without negative pressure, the following procedures may be followed. Figures 4A-4D Similar procedures as described in . However, the wound dressing does not include a port or fluid connector and the dressing will not be connected to a Figure 4C The negative pressure source described in.

[0129] Other variants Any values ​​for thresholds, limits, durations, etc. provided herein are not intended to be absolute and, therefore, may be approximate. Furthermore, any thresholds, limits, durations, etc. provided herein may be fixed or, or automatically or by the user, changeable. Furthermore, relative terms relative to a reference value as used herein, such as exceed, be greater than, be less than, etc., are intended to also encompass being equal to a reference value. For example, exceeding a positive reference value may include being equal to or greater than a reference value. Additionally, relative terms relative to a reference value as used herein, such as exceed, be greater than, be less than, etc., are also intended to encompass the inverse of the disclosed relationship, such as being less than, be less than, be greater than, etc. relative to a reference value. Furthermore, although various process blocks may be described in terms of determining whether a value meets or does not meet a particular threshold, these blocks may be understood similarly, for example, in terms of values ​​(i) being less than or greater than a threshold or (ii) meeting or not meeting a threshold.

[0130] Features, materials, characteristics, or combinations described in conjunction with a particular aspect, embodiment, or example are to be understood as applicable to any other aspect, embodiment, or example described herein unless incompatible therewith. All features disclosed in this specification (including any accompanying claims, abstract, and drawings), and / or all steps of any method or process so disclosed, may be combined in any combination, except where at least some of such features or steps are mutually exclusive. Protection is not limited to the details of any foregoing embodiments. Protection extends to any novel feature or any novel combination of features disclosed in this specification (including any accompanying claims, abstract, and drawings), or to any novel feature or any novel combination of steps of any method or process so disclosed.

[0131] Although certain embodiments have been described, these embodiments are presented only as examples and are not intended to limit the scope of protection. In fact, the novel methods and systems described herein can be embodied in a variety of other forms. In addition, various omissions, substitutions, and changes in the form of the methods and systems described herein can be made. Those skilled in the art will understand that, in some embodiments, the actual steps taken in the methods shown or disclosed may differ from the steps shown in the accompanying drawings. Depending on the embodiment, some of the above-mentioned steps may be removed, and other steps may be added. For example, the actual steps or order of steps taken in the disclosed process may differ from those shown in the figures. Depending on the embodiment, some of the above-mentioned steps may be removed, and other steps may be added. For example, the various components shown in the figures may be implemented as software or firmware on a processor, controller, ASIC, FPGA, or dedicated hardware. Hardware components such as controllers, processors, ASICs, FPGAs, etc. may include logic circuits. In addition, the features and attributes of the specific embodiments disclosed above can be combined in different ways to form additional embodiments, all of which fall within the scope of the present disclosure.

[0132] Conditional language, such as "can," "may," "might," or "could," unless expressly stated otherwise or otherwise understood in the context of use, is generally intended to convey that certain embodiments include, while other embodiments do not, certain features, elements, or steps. Thus, such conditional language is generally not intended to imply that one or more embodiments in any way require a feature, element, or step, or that one or more embodiments must include logic for determining, with or without user input or prompting, whether such feature, element, or step is included or performed in any particular embodiment. The terms "including," "comprising," "having," and the like are synonymous and are used in an open-ended, inclusive manner that does not exclude additional elements, features, actions, operations, and the like. Furthermore, the term "or" is used in its inclusive sense (rather than its exclusive sense) so that, when used, for example, to connect a list of elements, the term "or" means one, some, or all of the elements in the list. Furthermore, in addition to its ordinary meaning, the term "each" as used herein may refer to any subset of a set of elements to which the term "each" applies.

[0133] Unless expressly stated otherwise, conjunctive language such as the phrase "at least one of X, Y, and Z" is understood in the context as generally used to indicate that an item, term, etc. can be X, Y, or Z. Thus, such conjunctive language is generally not meant to imply that certain embodiments require the presence of at least one of X, at least one of Y, and at least one of Z.

[0134] As used herein, language of degree, such as the terms "about," "approximately," "substantially," and "approximately" as used herein, refers to a value, amount, or characteristic that is close to a specified value, amount, or characteristic that still performs the desired function or achieves the desired result. For example, the terms "about," "approximately," "substantially," and "approximately" may mean within less than 10%, less than 5%, less than 1%, less than 0.1%, and less than 0.01% of the specified amount. As another example, in certain embodiments, the terms "substantially parallel" and "approximately parallel" refer to a value, amount, or characteristic that deviates from exact parallelism by less than or equal to 15 degrees, 10 degrees, 5 degrees, 3 degrees, 1 degree, or 0.1 degrees.

[0135] All features disclosed in this specification (including any accompanying presentation, claims, abstract, and drawings), and / or all steps of any method or process so disclosed, may be combined in any combination, except where at least some of such features or steps are mutually exclusive. The present disclosure is not limited to the details of any foregoing embodiments. The present disclosure extends to any novel one or any novel combination of features disclosed in this specification (including any accompanying claims, abstract, and drawings), or any novel one or any novel combination of steps of any method or process so disclosed.

[0136] It will be apparent to those skilled in the art that various modifications to the specific implementations described in this disclosure will be apparent, and the general principles defined herein may be applied to other embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not intended to be limited to those embodiments shown herein, but rather to the widest scope consistent with the principles and features disclosed herein. Certain embodiments of the present disclosure are encompassed in the set of claims listed below or presented in the future. The language of the claims will be interpreted broadly based on the language employed in the claims and is not limited to the examples described in this specification or during the examination of the application, which examples should be interpreted as non-exclusive. The scope of this disclosure is not intended to be limited by the specific disclosure of the preferred embodiments herein, and may be defined by the claims set forth herein or claims set forth in the future.

Claims

1. A wound monitoring device comprising: A wound dressing configured to be positioned in contact with one or more of a wound or skin surrounding a wound, the wound dressing comprising at least one substantially flexible substrate supporting a plurality of sensors, the substantially flexible substrate comprising at least one of a substantially flexible printed circuit or a substantially flexible non-conductive mesh, a first sensor of the plurality of sensors being located on the substrate and configured to obtain measurements of the skin surrounding the wound, and a second sensor of the plurality of sensors being located on the substrate and configured to obtain measurements of the wound, wherein the wound dressing comprises a perforated wound contact layer.

2. The apparatus of claim 1, wherein the substrate is sized to extend at least partially beyond the area of ​​the wound and is configured to be positioned at least partially over the skin surrounding the wound.

3. The device of any one of claims 1-2, wherein the substantially flexible printed circuit comprises a flexible polymer.

4. The apparatus of any one of claims 1-3, wherein at least some of the plurality of sensors are electrically connected to each other, and wherein the plurality of sensors are configured to be electrically connected to a controller and a power source.

5. The apparatus of claim 4, wherein the controller is configured to receive data from the plurality of sensors and transmit the received data to a computing device, the computing device being configured to process the received data to determine one or more conditions associated with the wound.

6. The apparatus of claim 5, wherein at least one of the controller or the processing device is configured to indicate that the wound is healing based on one or more conditions associated with the wound.

7. The device according to any one of claims 1 to 6, wherein the plurality of sensors comprises one or more temperature sensors, conductivity sensors, multispectral optical measurement sensors, pH sensors, pressure sensors, colorimetric sensors, optical sensors, ultraviolet (UV) sensors or infrared (IR) sensors.

8. The device of any one of claims 1-7, wherein the plurality of sensors includes a skin elasticity sensor configured to perform an ultrasound scan of a skin area surrounding a wound.

9. The device of any one of claims 1-8, wherein the first sensor and the second sensor are SpO2 sensors.

10. The device of any preceding claim, wherein the substrate is located on or in the wound contact layer.

11. The apparatus of claim 10, further comprising an absorbent layer positioned over the wound contact layer and a backing layer positioned over the wound contact layer, wherein the wound contact layer is sealed to the backing layer.

12. The apparatus of claim 11, further comprising a port on the backing layer configured to connect the wound dressing to a source of negative pressure.

13. The apparatus of any one of claims 1-12, wherein the wound dressing is comprised in a multi-layer wound dressing configured to treat a wound without the use of negative pressure.

14. The apparatus of any one of claims 1-13, further comprising a wound packing layer and a drape configured to be positioned over a wound separately from the wound dressing.

15. The apparatus of any one of claims 1-12 or 14, further comprising a negative pressure source configured to be in fluid communication with the wound dressing and further configured to apply negative pressure to the wound.

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