WO2021148924A1 - Systèmes formant interface avec la plaie mettant en oeuvre des couches microporeuses pour la gestion des liquides - Google Patents

Systèmes formant interface avec la plaie mettant en oeuvre des couches microporeuses pour la gestion des liquides Download PDF

Info

Publication number
WO2021148924A1
WO2021148924A1 PCT/IB2021/050343 IB2021050343W WO2021148924A1 WO 2021148924 A1 WO2021148924 A1 WO 2021148924A1 IB 2021050343 W IB2021050343 W IB 2021050343W WO 2021148924 A1 WO2021148924 A1 WO 2021148924A1
Authority
WO
WIPO (PCT)
Prior art keywords
dressing
perforations
fluid
layer
manifold
Prior art date
Application number
PCT/IB2021/050343
Other languages
English (en)
Inventor
Christopher Brian Locke
Timothy Mark Robinson
Original Assignee
Kci Licensing, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Kci Licensing, Inc. filed Critical Kci Licensing, Inc.
Publication of WO2021148924A1 publication Critical patent/WO2021148924A1/fr

Links

Classifications

    • A61F13/05—
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F13/00—Bandages or dressings; Absorbent pads
    • A61F13/02—Adhesive plasters or dressings
    • A61F13/0203—Adhesive plasters or dressings having a fluid handling member
    • A61F13/0206—Adhesive plasters or dressings having a fluid handling member the fluid handling member being absorbent fibrous layer, e.g. woven or nonwoven absorbent pad, island dressings

Definitions

  • the invention set forth in the appended claims relates generally to tissue treatment systems and more particularly, but without limitation, to dressings for tissue treatment and methods for tissue treatment with negative pressure.
  • Negative-pressure therapy may provide a number of benefits, including migration of epithelial and subcutaneous tissues, improved blood flow, and micro deformation of tissue at a wound site. Together, these benefits can increase development of granulation tissue and reduce healing times.
  • cleansing a tissue site can be highly beneficial for new tissue growth.
  • a wound or a cavity can be washed out with a liquid solution for therapeutic purposes.
  • These practices are commonly referred to as “irrigation” and “lavage” respectively.
  • “Instillation” is another practice that generally refers to a process of slowly introducing fluid to a tissue site and leaving the fluid for a prescribed period of time before removing the fluid.
  • instillation of topical treatment solutions over a wound bed can be combined with negative- pressure therapy to further promote wound healing by loosening soluble contaminants in a wound bed and removing infectious material. As a result, soluble bacterial burden can be decreased, contaminants removed, and the wound cleansed.
  • a dressing for treating tissue may comprise a composite of dressing layers, including a fluid-control layer and a manifold adjacent the fluid-control layer.
  • the fluid-control layer comprises a plurality of micropores and a plurality of perforations.
  • the dressing may further comprise a sealing layer formed from a silicone gel with a central area removed to define a treatment aperture.
  • the treatment aperture may be in fluid communication with at least some of the plurality of perforations in the fluid-control layer.
  • the dressing may further comprise a cover comprising a film disposed over the manifold and coupled to the sealing layer around the manifold with pressure-sensitive adhesive.
  • the pressure- sensitive adhesive may be disposed adjacent the plurality of perforations in in the sealing layer.
  • the fluid-control layer may comprise a polymer film with micropores formed in the film.
  • the fluid-control layer may comprise a sheet of vapor-permeable and liquid- impermeable polyethylene fibers.
  • the fluid-control layer may be coupled to the manifold.
  • the fluid-control layer may be laminated to the manifold by a hot melt process.
  • the fluid-control layer may be bonded to the manifold by an adhesive.
  • the perforations comprise holes in the fluid-control layer.
  • the perforations may comprise slits formed in the fluid-control layer.
  • the manifold comprises a first edge which defines a manifold face adjacent to the fluid-control layer.
  • the fluid-control layer may have a second edge defining a fluid-control face adjacent to the manifold face and having a similar shape to the manifold face.
  • the manifold face may be at least as large as the fluid-control face.
  • the fluid-control face may also be larger than the treatment aperture in example embodiments.
  • at least one of the manifold and the fluid-control layer may be coupled to a margin around the treatment aperture.
  • the treatment aperture may be complementary to the manifold. The treatment aperture may form a window around the manifold in additional examples.
  • the micropores may have a width in a range of about 0.4 microns to about 10 microns.
  • the holes in the fluid-control layer may each have a width in a range of about 1 millimeter to about 5 millimeters.
  • the slits formed in the fluid-control layer may each have a length in a range of about 2 millimeters to about 5 millimeters.
  • the fluid-control layer may comprise a moisture-vapor transmission rate in a range of about 500 g/m 2 /day to about 1,000 g/m 2 /day.
  • the fluid-control layer comprises a thickness in a range of about 10 microns to about 100 microns.
  • the margin around the treatment aperture may have a width in a range of about 2 millimeters to about 3 millimeters.
  • the treatment aperture may have a width in a range of about 90 millimeters to about 110 millimeters in some embodiments.
  • the treatment aperture may have a length in a range of about 150 millimeters to about 160 millimeters.
  • a dressing for treating a tissue site with negative pressure may comprise a manifold with a contact layer adjacent the manifold.
  • a plurality of micropores and a plurality of first perforations may be formed in the contact layer.
  • the dressing may also comprise a sealing layer with a plurality of second perforations. At least some of the second perforations may be aligned with at least some of the first perforations and with some of the micropores in example embodiments.
  • the first perforations may comprise circular holes in the contact layer.
  • the first perforations may comprise slits formed in the contact layer.
  • the contact layer may be coupled to the manifold in some examples, such as by being laminated to the manifold by a hot melt process or bonded to the manifold by an adhesive in exemplary embodiments.
  • the dressing may further comprise a cover comprising a liquid-impermeable film and pressure-sensitive adhesive.
  • the film may be disposed over the manifold and coupled to the sealing layer around the manifold.
  • the pressure-sensitive adhesive may be disposed adjacent the plurality of second perforations.
  • the micropores may each have width in a range of about 0.4 microns to about 10 microns.
  • the first perforations in the film may each have a width in a range of about 1 millimeter to about 5 millimeters.
  • the first perforations may comprise slits formed in the contact layer, each with a length in a range of about 2 millimeters to about 5 millimeters.
  • the contact layer may comprise a moisture-vapor transmission rate in a range of about 500 g/m 2 /day to about 1,000 g/m 2 /day.
  • the contact layer may comprise a thickness in a range of about 10 microns to 100 microns in additional example embodiments.
  • the second perforations may be circular and have a diameter in a range of about 7 millimeters to about 9 millimeters.
  • a dressing for treating a tissue site with negative pressure may comprise a cover having an adhesive, a manifold, a polymer film having perforations and a plurality of micropores, and a silicone gel having perforations and a treatment aperture.
  • the cover, the manifold, the polymer film, and the silicone gel may be assembled in a stacked relationship.
  • the cover and the silicone gel may enclose the manifold.
  • the polymer film may be at least partially exposed through the treatment aperture in some examples.
  • at least some of the adhesive may be exposed through the perforations in the silicone gel around the treatment aperture .
  • the treatment aperture corresponds to a surface of the manifold in some example embodiments.
  • the treatment aperture forms a frame around the manifold.
  • the perforated polymer film may have a moisture-vapor transmission rate in a range of about 500 g/m 2 /day to about 1,000 g/m 2 /day.
  • the perforated polymer film may comprise athickness in a range of about 10 microns to about 100 microns.
  • a dressing for treating a tissue site with negative pressure comprises a manifold and a fluid-control layer comprising a sheet of polyethylene fibers adjacent the manifold. A plurality of first perforations may be formed in the sheet in some examples.
  • the dressing may comprise a sealing layer comprising a plurality of second perforations.
  • the dressing may comprise a cover comprising a non-porous film and a pressure-sensitive adhesive.
  • the non-porous film may be impermeable to liquid and disposed over the manifold in some examples.
  • the non-porous film may be coupled to the sealing layer around the manifold, and the pressure -sensitive adhesive may be disposed adjacent the plurality of second perforations.
  • the sheet of polyethylene fibers may have a moisture-vapor transmission rate in a range of about 500 g/m 2 /day to about 1,000 g/m 2 /day.
  • the sheet of polyethylene fibers may be permeable to vapor and impermeable to liquid in more particular example embodiments.
  • a dressing for treating a tissue site with negative pressure may comprise a cover having an adhesive, a manifold, a sheet of polyethylene fibers having a plurality of perforations formed in the sheet, and a perforated silicone gel having a treatment aperture assembled in a stacked relationship.
  • the cover and the perforated silicone gel may enclose the manifold.
  • the sheet may be at least partially exposed through the treatment aperture in exemplary embodiments.
  • at least some of the adhesive may be exposed through the perforated silicone gel around the treatment aperture.
  • the perforations may comprise slits formed in the sheet of polyethylene fibers.
  • Figure 1 is a functional block diagram of an example embodiment of a therapy system that can provide negative-pressure treatment and instillation treatment in accordance with this specification;
  • Figure 2 is an assembly view of an example of a dressing, illustrating additional details that may be associated with some example embodiments of the therapy system of Figure 1 ;
  • Figure 2A is a detail view illustrating enlarged details that may be associated with some example embodiments of the example dressing of Figure 2;
  • Figure 3 is a top view of the example dressing of Figure 2;
  • Figure 4 is a bottom view of the example dressing of Figure 2;
  • Figure 5 is an assembly view of another example of a dressing that may be associated with some example embodiments of the therapy system of Figure 1;
  • Figure 6 is a schematic view illustrating of an example configuration of perforations that may be associated with some embodiments of dressings;
  • Figure 7 is a schematic view of another example configuration of perforations
  • Figure 8 is a schematic view of another example configuration of perforations
  • Figure 9 is a schematic view of an example configuration of perforations
  • Figure 10 is a schematic view of another example configuration of perforations
  • Figure 11 is a schematic view of another example configuration of perforations
  • Figure 12 is a schematic view of another example configuration of perforations
  • Figure 13 is a schematic view of another example configuration of perforations
  • Figure 14 is a schematic view of another example configuration of perforations
  • Figure 15 is a schematic view of another example configuration of perforations
  • Figure 16 is a schematic view of another example configuration of perforations
  • Figure 17 is a schematic view of another example configuration of perforations
  • Figure 18 is a schematic view of another example configuration of perforations
  • Figure 19 is a schematic view of an example configuration of apertures in a layer that may be associated with some embodiments of the dressing of Figure 5;
  • Figure 20 is a schematic view of the example layer of Figure 6 overlaid on the example layer of Figure 19;
  • Figure 21 is a schematic diagram of an illustrative embodiment of the example of figure 2 on a patient.
  • Figure 21 A is a schematic diagram illustrating details that may be associated with some example embodiments of the example dressing of Figure 21;
  • Figure 2 IB is a schematic diagram illustrating details that may be associated with some example embodiments of the example dressing of Figure 21.
  • FIG. 1 is a simplified functional block diagram of an example embodiment of a therapy system 100 that can provide negative -pressure therapy with instillation of topical treatment solutions to a tissue site in accordance with this specification.
  • tissue site in this context broadly refers to a wound, defect, or other treatment target located on or within tissue, including, but not limited to, bone tissue, adipose tissue, muscle tissue, neural tissue, dermal tissue, vascular tissue, connective tissue, cartilage, tendons, or ligaments.
  • a wound may include chronic, acute, traumatic, subacute, and dehisced wounds, partial thickness bums, ulcers (such as diabetic, pressure, or venous insufficiency ulcers), flaps, and grafts, for example.
  • tissue site may also refer to areas of any tissue that are not necessarily wounded or defective, but are instead areas in which it may be desirable to add or promote the growth of additional tissue. For example, negative pressure may be applied to a tissue site to grow additional tissue that may be harvested and transplanted.
  • the therapy system 100 may include a source or supply of negative pressure, such as a negative-pressure source 105, and one or more distribution components.
  • a distribution component is preferably detachable and may be disposable, reusable, or recyclable.
  • a dressing, such as a dressing 110, and a fluid container, such as a container 115, are examples of distribution components that may be associated with some examples of the therapy system 100.
  • the dressing 110 may comprise or consist essentially of a tissue interface 120, a cover 125, or both in some embodiments.
  • a fluid conductor is another illustrative example of a distribution component.
  • a tube is an elongated, cylindrical structure with some flexibility, but the geometry and rigidity may vary.
  • some fluid conductors may be molded into or otherwise integrally combined with other components.
  • Distribution components may also include or comprise interfaces or fluid ports to facilitate coupling and de-coupling other components.
  • a dressing interface may facilitate coupling a fluid conductor to the dressing 110.
  • such a dressing interface may be a SENSAT.R.A.C.TM Pad available from Kinetic Concepts, Inc. of San Antonio, Texas.
  • the therapy system 100 may also include a regulator or controller, such as a controller 130. Additionally, the therapy system 100 may include sensors to measure operating parameters and provide feedback signals to the controller 130 indicative of the operating parameters. As illustrated in Figure 1, for example, the therapy system 100 may include a first sensor 135 and a second sensor 140 coupled to the controller 130.
  • the therapy system 100 may also include a source of instillation solution.
  • a solution source 145 may be fluidly coupled to the dressing 110, as illustrated in the example embodiment of Figure 1.
  • the solution source 145 may be fluidly coupled to a positive-pressure source such as a positive-pressure source 150, a negative-pressure source such as the negative-pressure source 105, or both in some embodiments.
  • a regulator such as an instillation regulator 155, may also be fluidly coupled to the solution source 145 and the dressing 110 to ensure proper dosage of instillation solution (e.g. saline) to a tissue site.
  • the instillation regulator 155 may comprise a piston that can be pneumatically actuated by the negative-pressure source 105 to draw instillation solution from the solution source during a negative-pressure interval and to instill the solution to a dressing during a venting interval.
  • the controller 130 may be coupled to the negative- pressure source 105, the positive-pressure source 150, or both, to control dosage of instillation solution to a tissue site.
  • the instillation regulator 155 may also be fluidly coupled to the negative-pressure source 105 through the dressing 110, as illustrated in the example of Figure 1.
  • Some components of the therapy system 100 may be housed within or used in conjunction with other components, such as sensors, processing units, alarm indicators, memory, databases, software, display devices, or user interfaces that further facilitate therapy.
  • the negative-pressure source 105 may be combined with the controller 130, the solution source 145, and other components into a therapy unit.
  • components of the therapy system 100 may be coupled directly or indirectly.
  • the negative-pressure source 105 may be directly coupled to the container 115 and may be indirectly coupled to the dressing 110 through the container 115. Coupling may include fluid, mechanical, thermal, electrical, or chemical coupling (such as a chemical bond), or some combination of coupling in some contexts.
  • the negative-pressure source 105 may be electrically coupled to the controller 130 and may be fluidly coupled to one or more distribution components to provide a fluid path to a tissue site.
  • components may also be coupled by virtue of physical proximity, being integral to a single structure, or being formed from the same piece of material.
  • a negative-pressure supply such as the negative-pressure source 105, may be a reservoir of air at a negative pressure or may be a manual or electrically-powered device, such as a vacuum pump, a suction pump, a wall suction port available at many healthcare facilities, or a micro pump, for example .
  • Negative pressure generally refers to a pressure less than a local ambient pressure, such as the ambient pressure in a local environment external to a sealed therapeutic environment. In many cases, the local ambient pressure may also be the atmospheric pressure at which a tissue site is located. Alternatively, the pressure may be less than a hydrostatic pressure associated with tissue at the tissue site. Unless otherwise indicated, values of pressure stated herein are gauge pressures.
  • references to increases in negative pressure typically refer to a decrease in absolute pressure, while decreases in negative pressure typically refer to an increase in absolute pressure. While the amount and nature of negative pressure provided by the negative-pressure source 105 may vary according to therapeutic requirements, the pressure is generally a low vacuum, also commonly referred to as a rough vacuum, between -5 mm Hg (-667 Pa) and -500 mm Hg (-66.7 kPa). Common therapeutic ranges are between - 50 mm Hg (-6.7 kPa) and -300 mm Hg (-39.9 kPa).
  • the container 115 is representative of a container, canister, pouch, or other storage component, which can be used to manage exudates and other fluids withdrawn from a tissue site.
  • a rigid container may be preferred or required for collecting, storing, and disposing of fluids.
  • fluids may be properly disposed of without rigid container storage, and a re-usable container could reduce waste and costs associated with negative-pressure therapy.
  • a controller such as the controller 130, may be a microprocessor or computer programmed to operate one or more components of the therapy system 100, such as the negative- pressure source 105.
  • the controller 130 may be a microcontroller, which generally comprises an integrated circuit containing a processor core and a memory programmed to directly or indirectly control one or more operating parameters of the therapy system 100. Operating parameters may include the power applied to the negative-pressure source 105, the pressure generated by the negative-pressure source 105, or the pressure distributed to the tissue interface 120, for example.
  • the controller 130 is also preferably configured to receive one or more input signals, such as a feedback signal, and programmed to modify one or more operating parameters based on the input signals.
  • Sensors such as the first sensor 135 and the second sensor 140, are generally known in the art as any apparatus operable to detect or measure a physical phenomenon or property, and generally provide a signal indicative of the phenomenon or property that is detected or measured.
  • the first sensor 135 and the second sensor 140 may be configured to measure one or more operating parameters of the therapy system 100.
  • the first sensor 135 may be a transducer configured to measure pressure in a pneumatic pathway and convert the measurement to a signal indicative of the pressure measured.
  • the first sensor 135 may be a piezo-resistive strain gauge.
  • the second sensor 140 may optionally measure operating parameters of the negative-pressure source 105, such as a voltage or current, in some embodiments.
  • the signals from the first sensor 135 and the second sensor 140 are suitable as an input signal to the controller 130, but some signal conditioning may be appropriate in some embodiments.
  • the signal may need to be filtered or amplified before it can be processed by the controller 130.
  • the signal is an electrical signal, but may be represented in other forms, such as an optical signal.
  • the tissue interface 120 can be generally adapted to partially or fully contact a tissue site.
  • the tissue interface 120 may take many forms, and may have many sizes, shapes, or thicknesses, depending on a variety of factors, such as the type of treatment being implemented or the nature and size of a tissue site.
  • the size and shape of the tissue interface 120 may be adapted to the contours of deep and irregular shaped tissue sites. Any or all of the surfaces of the tissue interface 120 may have an uneven, coarse, or jagged profile.
  • the tissue interface 120 may comprise or consist essentially of a manifold.
  • a manifold in this context may comprise or consist essentially of a means for collecting or distributing fluid across the tissue interface 120 under pressure.
  • a manifold may be adapted to receive negative pressure from a source and distribute negative pressure through multiple apertures across the tissue interface 120, which may have the effect of collecting fluid from across a tissue site and drawing the fluid toward the source.
  • the fluid path may be reversed or a secondary fluid path may be provided to facilitate delivering fluid, such as fluid from a source of instillation solution, across a tissue site.
  • the cover 125 may provide a bacterial barrier and protection from physical trauma.
  • the cover 125 may also be constructed from a material that can reduce evaporative losses and provide a fluid seal between two components or two environments, such as between a therapeutic environment and a local external environment.
  • the cover 125 may comprise or consist of, for example, an elastomeric fdm or membrane that can provide a seal adequate to maintain a negative pressure at a tissue site for a given negative-pressure source.
  • the cover 125 may have a high moisture-vapor transmission rate (MVTR) in some applications.
  • MVTR moisture-vapor transmission rate
  • the MVTR may be at least 250 grams per square meter per twenty-four hours in some embodiments, measured using an upright cup technique according to ASTM E96/E96M Upright Cup Method at 38°C and 10% relative humidity (RH). In some embodiments, an MVTR up to 5,000 grams per square meter per twenty-four hours may provide effective breathability and mechanical properties.
  • the cover 125 may be a polymer drape, such as a polyurethane fdm, that is permeable to water vapor but impermeable to liquid.
  • a polymer drape such as a polyurethane fdm
  • Such drapes typically have a thickness in the range of 25-50 microns.
  • the permeability generally should be low enough that a desired negative pressure may be maintained.
  • the cover 125 may comprise, for example, one or more of the following materials: polyurethane (PU), such as hydrophilic polyurethane; cellulosics; hydrophilic polyamides; polyvinyl alcohol; polyvinyl pyrrolidone; hydrophilic acrylics; silicones, such as hydrophilic silicone elastomers; natural rubbers; polyisoprene; styrene butadiene rubber; chloroprene rubber; polybutadiene; nitrile rubber; butyl rubber; ethylene propylene rubber; ethylene propylene diene monomer; chlorosulfonated polyethylene; polysulfide rubber; ethylene vinyl acetate (EVA); co-polyester; and polyether block polyamide copolymers.
  • PU polyurethane
  • PU polyurethane
  • hydrophilic polyurethane such as hydrophilic polyurethane
  • cellulosics such as cellulosics; hydrophilic polyamides;
  • the cover 125 may comprise INSPIRE 2301 having an MVTR (upright cup technique) of 2600 g/m 2 /24 hours and a thickness of about 30 microns.
  • An attachment device may be used to attach the cover 125 to an attachment surface, such as undamaged epidermis, a gasket, or another cover.
  • the attachment device may take many forms.
  • an attachment device may be a medically-acceptable, pressure -sensitive adhesive configured to bond the cover 125 to epidermis around a tissue site.
  • some or all of the cover 125 may be coated with an adhesive, such as an acrylic adhesive, which may have a coating weight of about 25-65 grams per square meter (g.s.m.). Thicker adhesives, or combinations of adhesives, may be applied in some embodiments to improve the seal and reduce leaks.
  • Example embodiments of an attachment device may include a double-sided tape, paste, hydrocolloid, hydrogel, silicone gel, or organogel.
  • the solution source 145 may also be representative of a container, canister, pouch, bag, or other storage component, which can provide a solution for instillation therapy.
  • Compositions of solutions may vary according to a prescribed therapy, but examples of solutions that may be suitable for some prescriptions include hypochlorite-based solutions, silver nitrate (0.5%), sulfur-based solutions, biguanides, cationic solutions, and isotonic solutions.
  • the tissue interface 120 may be placed within, over, on, or otherwise proximate to a tissue site. If the tissue site is a wound, for example, the tissue interface 120 may partially or completely fill the wound, or it may be placed over the wound.
  • the cover 125 may be placed over the tissue interface 120 and sealed to an attachment surface near a tissue site. For example, the cover 125 may be sealed to undamaged epidermis peripheral to a tissue site.
  • the dressing 110 can provide a sealed therapeutic environment proximate to a tissue site, substantially isolated from the external environment, and the negative-pressure source 105 can reduce pressure in the sealed therapeutic environment.
  • the fluid mechanics of using a negative-pressure source to reduce pressure in another component or location, such as within a sealed therapeutic environment can be mathematically complex.
  • the basic principles of fluid mechanics applicable to negative-pressure therapy and instillation are generally well-known to those skilled in the art, and the process of reducing pressure may be described illustratively herein as “delivering,” “distributing,” or “generating” negative pressure, for example.
  • exudate and other fluid flow toward lower pressure along a fluid path.
  • downstream typically implies something in a fluid path relatively closer to a source of negative pressure or further away from a source of positive pressure.
  • upstream implies something relatively further away from a source of negative pressure or closer to a source of positive pressure.
  • inlet or outlet in such a frame of reference. This orientation is generally presumed for purposes of describing various features and components herein.
  • the fluid path may also be reversed in some applications, such as by substituting a positive-pressure source for a negative-pressure source, and this descriptive convention should not be construed as a limiting convention.
  • Negative pressure applied across the tissue site through the tissue interface 120 in the sealed therapeutic environment can induce macro-strain and micro-strain in the tissue site. Negative pressure can also remove exudate and other fluid from a tissue site, which can be collected in container [0066]
  • the controller 130 may receive and process data from one or more sensors, such as the first sensor 135. The controller 130 may also control the operation of one or more components of the therapy system 100 to manage the pressure delivered to the tissue interface 120.
  • controller 130 may include an input for receiving a desired target pressure and may be programmed for processing data relating to the setting and inputting of the target pressure to be applied to the tissue interface 120.
  • the target pressure may be a fixed pressure value set by an operator as the target negative pressure desired for therapy at a tissue site and then provided as input to the controller 130.
  • the target pressure may vary from tissue site to tissue site based on the type of tissue forming a tissue site, the type of injury or wound (if any), the medical condition of the patient, and the preference of the attending physician.
  • the controller 130 can operate the negative -pressure source 105 in one or more control modes based on the target pressure and may receive feedback from one or more sensors to maintain the target pressure at the tissue interface 120.
  • the controller 130 may have a continuous pressure mode, in which the negative-pressure source 105 is operated to provide a constant target negative pressure for the duration of treatment or until manually deactivated. Additionally or alternatively, the controller may have an intermittent pressure mode. For example, the controller 130 can operate the negative-pressure source 105 to cycle between a target pressure and atmospheric pressure. For example, the target pressure may be set at a value of 135 mmHg for a specified period of time (e.g., 5 min), followed by a specified period of time (e.g., 2 min) of deactivation. The cycle can be repeated by activating the negative- pressure source 105, which can form a square wave pattern between the target pressure and atmospheric pressure.
  • the increase in negative-pressure from ambient pressure to the target pressure may not be instantaneous.
  • the negative-pressure source 105 and the dressing 110 may have an initial rise time.
  • the initial rise time may vary depending on the type of dressing and therapy equipment being used.
  • the initial rise time for one therapy system may be in a range of about 20-30 mmHg/second and in a range of about 5-10 mmHg/second for another therapy system. If the therapy system 100 is operating in an intermittent mode, the repeating rise time may be a value substantially equal to the initial rise time.
  • the target pressure can vary with time.
  • the target pressure may vary in the form of a triangular waveform, varying between a negative pressure of 50 and 135 mmHg with a rise time 305 set at a rate of +25 mmHg/min. and a descent time 310 set at -25 mmHg/min.
  • the triangular waveform may vary between negative pressure of 25 and 135 mmHg with a rise time 305 set at a rate of +30 mmHg/min and a descent time 310 set at -30 mmHg/min.
  • the controller 130 may control or determine a variable target pressure in a dynamic pressure mode, and the variable target pressure may vary between a maximum and minimum pressure value that may be set as an input prescribed by an operator as the range of desired negative pressure.
  • the variable target pressure may also be processed and controlled by the controller 130, which can vary the target pressure according to a predetermined waveform, such as a triangular waveform, a sine waveform, or a saw-tooth waveform.
  • the waveform may be set by an operator as the predetermined or time-varying negative pressure desired for therapy.
  • the controller 130 may receive and process data, such as data related to instillation solution prescribed by a clinician, the volume of fluid or solution to be instilled to a tissue site (“fill volume”), and the amount of time prescribed for leaving solution at a tissue site (“dwell time”) before applying a negative pressure to the tissue site.
  • the fill volume may be, for example, between 10 and 500 mL, and the dwell time may be between one second to 30 minutes.
  • the controller 130 may also control the operation of one or more components of the therapy system 100 to instill solution. For example, the controller 130 may manage fluid distributed from the solution source 145 to the tissue interface 120.
  • fluid may be instilled to a tissue site by applying a negative pressure from the negative-pressure source 105 to reduce the pressure at the tissue site, drawing solution into the tissue interface 120.
  • solution may be instilled to a tissue site by applying a positive pressure from the positive-pressure source 150 to move solution from the solution source 145 to the tissue interface 120.
  • the solution source 145 may be elevated to a height sufficient to allow gravity to move solution into the tissue interface 120.
  • the controller 130 may also control the fluid dynamics of instillation by providing a continuous flow of solution or an intermittent flow of solution. Negative pressure may be applied to provide either continuous flow or intermittent flow of solution. The application of negative pressure may be implemented to provide a continuous pressure mode of operation to achieve a continuous flow rate of instillation solution through the tissue interface 120, or it may be implemented to provide a dynamic pressure mode of operation to vary the flow rate of instillation solution through the tissue interface 120. In an intermittent mode, a specific fill volume and dwell time may be provided, depending, for example, on the type of tissue site being treated and the type of dressing being utilized. After or during instillation of solution, negative-pressure treatment may be applied. The controller 130 may be utilized to select a mode of operation and the duration of the negative pressure treatment before commencing another instillation cycle.
  • FIG. 2 is an assembly view of an example of the dressing 110 of Figure 1, illustrating additional details that may be associated with some embodiments in which the tissue interface 120 comprises more than one layer.
  • the tissue interface 120 comprises a first layer 205, a second layer 210, and a third layer 215.
  • the first layer 205 may be disposed adjacent to the second layer 210
  • the third layer 215 may also be disposed adjacent to the second layer 210 opposite the first layer 205.
  • the first layer 205 and the second layer 210 may be stacked so that the first layer 205 is in contact with the second layer 210.
  • the first layer 205 may also be bonded to the second layer 210 in some embodiments.
  • the second layer 210 may be coextensive with a face of the first layer 205.
  • at least some portion of the third layer 215 may be bonded to the second layer 210.
  • the first layer 205 generally comprises or consists essentially of a manifold or a manifold layer, which provides a means for collecting or distributing fluid across the tissue interface 120 under pressure.
  • the first layer 205 may be adapted to receive negative pressure from a source and distribute negative pressure through multiple apertures across the tissue interface 120, which may have the effect of collecting fluid from across a tissue site and drawing fluid toward the source.
  • the fluid path may be reversed or a secondary fluid path may be provided to facilitate delivering fluid, such as from a source of instillation solution, across the tissue interface 120.
  • the pathways of the first layer 205 may be interconnected to improve distribution or collection of fluids.
  • the first layer 205 may comprise or consist essentially of a porous material having interconnected fluid pathways.
  • suitable porous material that comprise or can be adapted to form fluid pathways may include cellular foam, including open-cell foam such as reticulated foam, porous tissue collections, and other porous materials such as gauze or felted mat that generally includes pores, edges, and/or walls.
  • Liquids, gels, and other foams may also include or be cured to include apertures and fluid pathways.
  • the first layer 205 may additionally or alternatively comprise projections that form interconnected fluid pathways.
  • the first layer 205 may be molded to provide surface projections that define interconnected fluid pathways.
  • the first layer 205 may comprise or consist essentially of a reticulated foam having pore sizes and free volume that may vary according to needs of a prescribed therapy.
  • a reticulated foam having a free volume of at least 90% may be suitable for many therapy applications, and a foam having an average pore size in a range of 400-600 microns may be particularly suitable for some types of therapy.
  • the tensile strength of the first layer 205 may also vary according to needs of a prescribed therapy. For example, the tensile strength of a foam may be increased for instillation of topical treatment solutions.
  • the 25% compression load deflection of the first layer 205 may be at least 0.35 pounds per square inch, and the 65% compression load deflection may be at least 0.43 pounds per square inch.
  • the tensile strength of the first layer 205 may be at least 10 pounds per square inch.
  • the first layer 205 may have atear strength of at least 2.5 pounds per inch.
  • the first layer 205 may be a foam comprised of polyols such as polyester or polyether, isocyanate such as toluene diisocyanate, and polymerization modifiers such as amines and tin compounds.
  • the first layer 205 may be a reticulated polyurethane foam such as used in GRANUFOAMTM dressing or V.A.C.
  • VERAFLOTM dressing both available from KCI of San Antonio, Texas.
  • suitable materials for the first layer 205 may include non-woven fabrics (Libeltex, Freudenberg), three-dimensional (3D) polymeric structures (molded polymers, embossed and formed films, and fusion bonded films [Supracore]), and mesh, for example.
  • the first layer 205 may include a 3D textile, such as various textiles commercially available from Baltex, Muller, and Heathcoates.
  • a 3D textile of polyester fibers may be particularly advantageous for some embodiments.
  • the first layer 205 may comprise or consist essentially of a three-dimensional weave of polyester fibers.
  • the fibers may be elastic in at least two dimensions.
  • a puncture-resistant fabric of polyester and cotton fibers having a weight of about 650 grams per square meter and a thickness of about 1-2 millimeters may be particularly advantageous for some embodiments.
  • Such a puncture-resistant fabric may have a warp tensile strength of about 330-340 kilograms and a weft tensile strength of about 270-280 kilograms in some embodiments.
  • Another particularly suitable material may be a polyester spacer fabric having a weight of about 470 grams per square meter, which may have a thickness of about 4-5 millimeters in some embodiments.
  • Such a spacer fabric may have a compression strength of about 20-25 kilopascals (at 40% compression).
  • the first layer 205 may comprise or consist of a material having substantial linear stretch properties, such as a polyester spacer fabric having 2-way stretch and a weight of about 380 grams per square meter.
  • a suitable spacer fabric may have a thickness of about 3-4 millimeters, and may have a warp and weft tensile strength of about 30-40 kilograms in some embodiments.
  • the fabric may have a close-woven layer of polyester on one or more opposing faces in some examples.
  • a woven layer may be advantageously disposed on a first layer 205 to face a tissue site.
  • the first layer 205 generally has a first planar surface and a second planar surface opposite the first planar surface.
  • the thickness of the first layer 205 between the first planar surface and the second planar surface may also vary according to needs of a prescribed therapy. For example, the thickness of the first layer 205 may be decreased to relieve stress on other layers and to reduce tension on peripheral tissue. The thickness of the first layer 205 can also affect the conformability of the first layer 205.
  • a suitable foam may have a thickness in a range of about 5 millimeters to 10 millimeters.
  • Fabrics, including suitable 3D textiles and spacer fabrics may have a thickness in a range of about 2 millimeters to about 8 millimeters.
  • the second layer 210 may comprise or consist essentially of a means for controlling or managing fluid flow.
  • the second layer 210 may be a fluid-control layer comprising or consisting essentially of a liquid-impermeable, vapor-permeable elastomeric material.
  • the second layer 210 may comprise or consist essentially of a polymer film.
  • the second layer 210 may comprise or consist essentially of a polyolefin film, such as a polyethylene film.
  • FIG. 2A is a detail view showing additional details associated with example embodiments of the second layer 210.
  • Figure 2A illustrates some embodiments where the second layer 210 comprise micropores 220 formed through the second layer 210.
  • each micropore 220 may have a width in a range of about 0.4 microns to about 10 microns.
  • each of the micropores 220 may be substantially circular and have a diameter in a range of about 0.4 microns to about 10 microns.
  • each micropore 220 may be linear or irregularly shaped, and comprise a width in a range of about 0.4 microns to about 10 microns.
  • the micropores 220 may comprise regular shapes (such as circles), irregular shapes, or a mixture of regular and irregular shapes, each with a width in a range of about 0.4 microns to about 10 microns.
  • the dimensions and shape of each of the micropores 220 may depend on the dimensions and shape of the inorganic mineral fdlers or polymer particles or fibers which may be used to form the micropores 220 in some examples.
  • the second layer 210 may be formed from a polyolefin film.
  • a thin sheet of polyethylene may be blended with inorganic mineral fillers such as clays.
  • the thin sheet of polyethylene may be blended with polymer particles or fibers which are not soluble in the polyethylene layer, such as polyamide particles or fibers.
  • the mineral fillers, polymer particles, and/or fibers may have a width in a range of about 0.4 microns to about 10 microns, and may be substantially circular.
  • the mineral fillers, polymer particles, or fibers may comprise regular shapes (such as circles), irregular shapes, or a mixture of regular and irregular shapes, each with a width in a range of about 0.4 microns to about 10 microns.
  • the polyolefin film with blended inorganic mineral fillers, polymer particles, and/or fibers may be stretched along one or more axes, releasing the blended inorganic mineral fillers, polymer particles, and/or fibers.
  • micropores 220 are formed from the voids which remain behind in the polyolefin film after the blended inorganic mineral fillers, polymer particles, and/or fibers detach from the polyolefin film.
  • the second layer 210 with the micropores 220 may comprise a moisture-vapor transmission rate (MVTR) in a range of about 500 g/m 2 /day to about 1,000 g/m 2 /day in regions with the micropores 220.
  • MVTR moisture-vapor transmission rate
  • the second layer 210 may be formed of a sheet of compressed fine fibered webs, such as flashspun high density polyethylene fibers.
  • the second layer 210 may comprise or consist essentially of DuPontTM Tyvek® material to achieve an MVTR in a range of about 500 g/m 2 /day to about 1,000 g/m 2 /day.
  • the second layer 210 may comprise athickness in a range from about 10 microns to about 100 microns.
  • the second layer 210 with a MVTR in a range of about 500 g/m 2 /day to about 1,000 g/m 2 /day may be able to transmit dry fluid flow, but may not permit fluid flow when the second layer 210 is in contact with water in exemplary embodiments.
  • the second layer 210 may be described as vapor- permeable and liquid impermeable.
  • the second layer 210 may be hydrophobic.
  • the hydrophobicity of the second layer 210 may vary, but may have a contact angle with water of at least ninety degrees in some embodiments.
  • the second layer 210 may have a contact angle with water of no more than 150 degrees.
  • the contact angle of the second layer 210 may be in a range of at least 90 degrees to about 120 degrees, or in a range of at least 120 degrees to 150 degrees. Water contact angles can be measured using any standard apparatus.
  • contact angle measuring instruments can often include an integrated system involving a level stage, liquid dropper such as a syringe, camera, and software designed to calculate contact angles more accurately and precisely, among other things.
  • integrated systems may include the FTAl25, FTA200, FTA2000, and FTA4000 systems, all commercially available from First Ten Angstroms, Inc., of Portsmouth, VA, and the DTA25, DTA30, and DTA100 systems, all commercially available from Kruss GmbH of Hamburg, Germany.
  • water contact angles herein are measured using deionized and distilled water on a level sample surface for a sessile drop added from a height of no more than 5 cm in air at 20-25°C and 20-50% relative humidity. Contact angles herein represent averages of 5-9 measured values, discarding both the highest and lowest measured values.
  • the hydrophobicity of the second layer 210 may be further enhanced with a hydrophobic coating of other materials, such as silicones and fluorocarbons, either as coated from a liquid, or plasma coated.
  • the second layer 210 may be coupled to other layers, including the first layer 205.
  • the second layer 210 may be laminated to the first layer 205 using a hot melt process.
  • the second layer 210 may be bonded to the first layer 205 using a pattern coated adhesive.
  • the second layer 210 may be adapted for welding to polyurethane foams using heat, radio frequency (RF) welding, or other methods to generate heat such as ultrasonic welding.
  • RF welding may be particularly suitable for more polar materials, such as polyurethane, polyamides, polyesters and acrylates. Sacrificial polar interfaces may be used to facilitate RF welding of less polar film materials, such as polyethylene.
  • the area density of the second layer 210 may vary according to a prescribed therapy or application. In some embodiments, an area density of less than 40 grams per square meter may be suitable, and an area density of about 20-30 grams per square meter may be particularly advantageous for some applications.
  • the second layer 210 may have one or more fluid passages 225, which can be distributed uniformly or randomly across the second layer 210.
  • the fluid passages 225 may be bi-directional and pressure-responsive.
  • each of the fluid passages 225 generally may comprise or consist essentially of an elastic passage that is normally unstrained to substantially reduce liquid flow, and can expand or open in response to a pressure gradient.
  • the fluid passages 225 may comprise or consist essentially of perforations in the second layer 210. Perforations may be formed by removing material from the second layer 210. For example, perforations may be formed by cutting through the second layer 210, which may also deform the edges of the perforations in some embodiments.
  • the passages may be sufficiently small to form a seal or fluid restriction, which can substantially reduce or prevent liquid flow.
  • one or more of the fluid passages 225 may be an elastomeric valve that is normally closed when unstrained to substantially prevent liquid flow, and can open in response to a pressure gradient.
  • a fenestration in the second layer 210 may be a suitable valve for some applications. Fenestrations may also be formed by removing material from the second layer 210, but the amount of material removed and the resulting dimensions of the fenestrations may be up to an order of magnitude less than perforations, and may not deform the edges.
  • the fluid passages 225 may comprise or consist essentially of one or more slits, slots or combinations of slits and slots in the second layer 210.
  • the fluid passages 225 may comprise or consist of linear slots having a length less than 5 millimeters and a width less than 1 millimeter. The length may be at least 21millimeter, and the width may be at least 0.4 millimeters in some embodiments. A length of about 3 millimeters and a width of about 0.8 millimeters may be particularly suitable for many applications, and a tolerance of about 0.1 millimeter may also be acceptable. Such dimensions and tolerances may be achieved with a laser cutter, for example.
  • Slots of such configurations may function as imperfect valves that substantially reduce liquid flow in a normally closed or resting state.
  • such slots may form a flow restriction without being completely closed or sealed.
  • the slots can expand or open wider in response to a pressure gradient to allow increased liquid flow.
  • the third layer 215 may comprise or consist essentially of a sealing layer formed from a soft, pliable material suitable for providing a fluid seal with a tissue site, such as a suitable gel material, and may have a substantially flat surface.
  • the third layer 215 may comprise, without limitation, a silicone gel, a soft silicone, hydrocolloid, hydrogel, polyurethane gel, polyolefin gel, hydrogenated styrenic copolymer gel, a foamed gel, a soft closed cell foam such as polyurethanes and polyolefins coated with an adhesive, polyurethane, polyolefin, or hydrogenated styrenic copolymers.
  • the third layer 215 may have a thickness between about 200 microns (pm) and about 1000 microns (pm). In some embodiments, the third layer 215 may have a hardness between about 5 Shore OO and about 80 Shore OO. Further, the third layer 215 may be comprised of hydrophobic or hydrophilic materials.
  • the third layer 215 may be a hydrophobic-coated material.
  • the third layer 215 may be formed by coating a spaced material, such as, for example, woven, nonwoven, molded, or extruded mesh with a hydrophobic material.
  • the hydrophobic material for the coating may be a soft silicone, for example.
  • the third layer 215 may have a periphery 230 surrounding or around a treatment aperture 235, and apertures 240 in the periphery 230 disposed around the treatment aperture 235.
  • the treatment aperture 235 may be complementary or correspond to a surface area of the first layer 205 in some examples.
  • the treatment aperture 235 may form a frame, window, or other opening around a surface of the first layer 205.
  • the third layer 215 may also have comers 245 and edges 250. The comers 245 and the edges 250 may be part of the periphery 230.
  • the third layer 215 may have an interior border 255 around the treatment aperture 235, which may be substantially free of the apertures 240, as illustrated in the example of Figure 2.
  • the treatment aperture 235 may be symmetrical and centrally disposed in the third layer 215, forming an open central window.
  • the apertures 240 may be formed by cutting, perforating, or by application of local RF or ultrasonic energy, for example, or by other suitable techniques for forming an opening or perforation in the third layer 215.
  • the apertures 240 may have a uniform distribution pattern, or may be randomly distributed on the third layer 215.
  • the apertures 240 in the third layer 215 may have many shapes, including circles, squares, stars, ovals, polygons, slits, complex curves, rectilinear shapes, triangles, for example, or may have some combination of such shapes.
  • each of the apertures 240 may have uniform or similar geometric properties.
  • each of the apertures 240 may be circular apertures, having substantially the same diameter.
  • each of the apertures 240 may have a diameter of about 1 millimeter to about 50 millimeters. In other embodiments, the diameter of each of the apertures 240 may be about 1 millimeter to about 20 millimeters.
  • geometric properties of the apertures 240 may vary.
  • the diameter of the apertures 240 may vary depending on the position of the apertures 240 in the third layer 215.
  • the apertures 240 disposed in the periphery 230 may have a diameter between about 5 millimeters and about 10 millimeters. A range of about 7 millimeters to about 9 millimeters may be suitable for some examples.
  • the apertures 240 disposed in the comers 245 may have a diameter between about 7 millimeters and about 8 millimeters.
  • At least one of the apertures 240 in the periphery 230 of the third layer 215 may be positioned at the edges 250 of the periphery 230, and may have an interior cut open or exposed at the edges 250 that is in fluid communication in a lateral direction with the edges 250.
  • the lateral direction may refer to a direction toward the edges 250 and in the same plane as the third layer 215.
  • the apertures 240 in the periphery 230 may be positioned proximate to or at the edges 250 and in fluid communication in a lateral direction with the edges 250.
  • the apertures 240 positioned proximate to or at the edges 250 may be spaced substantially equidistant around the periphery 230 as shown in the example of Figure 2.
  • the spacing of the apertures 240 proximate to or at the edges 250 may be irregular.
  • the dressing 110 may further include an attachment device, such as an adhesive 260.
  • the adhesive 260 may be, for example, a medically- acceptable, pressure -sensitive adhesive that extends about a periphery, a portion, or an entire surface of the cover 125.
  • the adhesive 260 may be an acrylic adhesive having a coating weight between 25-65 grams per square meter (g.s.m.). Thicker adhesives, or combinations of adhesives, may be applied in some embodiments to improve the seal and reduce leaks.
  • such a layer of the adhesive 260 may be continuous or discontinuous. Discontinuities in the adhesive 260 may be provided by apertures or holes (not shown) in the adhesive 260.
  • the apertures or holes in the adhesive 260 may be formed after application of the adhesive 260 or by coating the adhesive 260 in patterns on a carrier layer, such as, for example, a side of the cover 125. Apertures or holes in the adhesive 260 may also be sized to enhance the MVTR of the dressing 110 in some example embodiments.
  • the dressing 110 may include a release liner 265 to protect the adhesive 260 prior to use.
  • the release liner 265 may also provide stiffness to assist with, for example, deployment of the dressing 110.
  • the release liner 265 may be, for example, a casting paper, a film, or polyethylene.
  • the release liner 265 may be a polyester material such as polyethylene terephthalate (PET), or similar polar semi crystalline polymer.
  • PET polyethylene terephthalate
  • the use of a polar semi-crystalline polymer for the release liner 265 may substantially preclude wrinkling or other deformation of the dressing 110.
  • the polar semi crystalline polymer may be highly orientated and resistant to softening, swelling, or other deformation that may occur when brought into contact with components of the dressing 110, or when subjected to temperature or environmental variations, or sterilization.
  • a release agent may be disposed on a side of the release liner 265 that is configured to contact the second layer 210.
  • the release agent may be a silicone coating and may have a release factor suitable to facilitate removal of the release liner 265 by hand and without damaging or deforming the dressing 110.
  • the release agent may be a fluorocarbon or a fluorosilicone, for example.
  • the release liner 265 may be uncoated or otherwise used without a release agent.
  • Figure 2 also illustrates one example of a fluid conductor 270 and a dressing interface 275.
  • the fluid conductor 270 may be a flexible tube, which can be fluidly coupled on one end to the dressing interface 275.
  • the dressing interface 275 may be an elbow connector, as shown in the example of Figure 2, which can be placed over an aperture 280 in the cover 125 to provide a fluid path between the fluid conductor 270 and the tissue interface 120.
  • the first layer 205 may be a foam, mesh, or non-woven coated with an antimicrobial agent.
  • the first layer may comprise antimicrobial elements, such as fibers coated with an antimicrobial agent.
  • some embodiments of the second layer 210 may be a polymer coated or mixed with an antimicrobial agent.
  • the fluid conductor 270 may additionally or alternatively be treated with one or more antimicrobial agents.
  • Suitable antimicrobial agents may include, for example, metallic silver, PHMB, iodine or its complexes and mixes such as povidone iodine, copper metal compounds, chlorhexidine, or some combination of these materials.
  • one or more of the components may be coated with a mixture that may include citric acid and collagen, which can reduce bio-fdms and infections.
  • the first layer 205 may be a foam coated with such a mixture.
  • Figure 3 is a top view of the dressing 110 in the example of Figure 2, as assembled, illustrating additional details that may be associated with some embodiments.
  • the cover 125 and the third layer 215 may have substantially the same perimeter shape and dimensions, so that the cover 125 and the third layer 215 are coextensive in some examples.
  • the cover 125 may be substantially transparent, allowing visibility of the apertures 240 in some embodiments.
  • the first layer 205 may be centrally disposed over the third layer 215, such as over the treatment aperture 235 (not visible in Figure 3).
  • the cover 125 may be disposed over the first layer 205 and coupled to the third layer 215 around the first layer 205 so that at least some of the adhesive 260 can be disposed adjacent to the apertures 240.
  • Figure 4 is a bottom view of the dressing 110 in the example of Figure 2, as assembled, illustrating additional details that may be associated with some embodiments.
  • a substantial number of the fluid passages 225 may be aligned or otherwise exposed through the treatment aperture 235, and at least some portion of the first layer 205 may be disposed adjacent to the fluid passages 225 opposite the treatment aperture 235.
  • the first layer 205 and the second layer 210 may be substantially aligned with the treatment aperture 235, or may extend across the treatment aperture 235.
  • the first layer 205 may have a first edge 405, and the second layer 210 may have a second edge 410.
  • the first edge 405 and the second edge 410 may have substantially the same shape so that adjacent faces of the first layer 205 and the second layer 210 are geometrically similar.
  • the first edge 405 and the second edge 410 may also be congruent in some examples, so that adjacent faces of the first layer 205 and the second layer 210 are substantially coextensive and have substantially the same surface area.
  • the first edge 405 defines a larger face of the first layer 205 than the face of the second layer 210 defined by the second edge 410, and the larger face of the first layer 205 extends past the smaller face of the second edge 410.
  • the faces defined by the first edge 405, the second edge 410, or both may also be geometrically similar to the treatment aperture 235 in some embodiments, as illustrated in the example of Figure 4, and may be larger than the treatment aperture 235.
  • the third layer 215 may have an overlay margin 415 around the treatment aperture 235, which may have an additional adhesive disposed therein.
  • the treatment aperture 235 may be an ellipse or a stadium in some embodiments.
  • the treatment aperture 235 may have an area that is equal to about 20% to about 80% of the area of the third layer 215 in some examples.
  • the treatment aperture 235 may also have an area that is equal to about 20% to about 80% of the area of a face of defined by the first edge 405 of the first layer 205.
  • a width of about 90 millimeters to about 110 millimeters and a length of about 150 millimeters to about 160 millimeters may be suitable for some embodiments of the treatment aperture 235.
  • the width of the treatment aperture 235 may be about 100 millimeters, and the length may be about 155 millimeters.
  • a suitable width for the overlay margin 415 may be about 2 millimeters to about 3 millimeters.
  • the overlay margin 415 may be coextensive with an area defined between the treatment aperture 235 and the first edge 405, and the adhesive may secure the first layer 205, the second layer 210, or both to the third layer 215.
  • Figure 5 is an assembly view of another example of the dressing 110 of Figure 1, illustrating additional details that may be associated with some embodiments. As illustrated in Figure 5, some examples of the third layer 215 may not have the treatment aperture 235, and the apertures 240 may be distributed in a uniform pattern across the third layer 215.
  • Figure 6 is a schematic view of an example of the second layer 210, illustrating additional details that may be associated with some embodiments.
  • the fluid passages 225 may each consist essentially of one or more slits having a length /. A length of about 3 millimeters may be particularly suitable for some embodiments.
  • Figure 6 additionally illustrates an example of a uniform distribution pattern of the fluid passages 225.
  • the fluid passages 225 are substantially coextensive with the second layer 210, and are distributed across the second layer 210 in a grid of parallel rows and columns, in which the slits are also mutually parallel to each other. In some embodiments, the rows may be spaced a distance d .
  • a distance of about 3 millimeters on center may be suitable for some embodiments.
  • the fluid passages 225 within each of the rows may be spaced a distance cl 2 . which may be about 3 millimeters on center in some examples.
  • the fluid passages 225 in adjacent rows may be aligned or offset in some embodiments. For example, adjacent rows may be offset, as illustrated in Figure 6, so that the fluid passages 225 are aligned in alternating rows and separated by a distance d . which may be about 6 millimeters in some embodiments.
  • the spacing of the fluid passages 225 may vary in some embodiments to increase the density of the fluid passages 225 according to therapeutic requirements.
  • Figures 7 through 14 are schematic diagrams illustrating additional details that may be associated with some embodiments of the second layer 210.
  • the fluid passages 225 may comprise a first plurality of perforations 705 and a second plurality of perforations 710.
  • Each of the first plurality of perforations 705 and the second plurality of perforations 710 may be linear or curved perforations, such as slots or slits.
  • the perforations are linear slots or slits
  • each of the first plurality of perforations 705 may have a length Li and each of the second plurality of perforations 710 may have a length L2.
  • each of the first plurality of perforations may have a length Li measured from an end of the curved slot or slit to the other end of the curved slot or slit
  • each of the second plurality of perforations may have a length L2 measured from an end of the curved slot or slit to the other end of the curved slot or slit.
  • the length Li may be equal to the length 1, 2 .
  • the first plurality of perforations 705 and the second plurality of perforations 710 may be distributed across the second layer in one or more rows in one direction or in different directions.
  • each of the first plurality of perforations 705 may have a first long axis.
  • the first long axis may be parallel to a first reference line 715 running in a first direction.
  • each of the second plurality of perforations 710 may have a second long axis.
  • the second long axis may be parallel to a second reference line 720 running in a second direction.
  • one or both of the first reference line 715 and the second reference line 720 may be defined relative to an edge 725 or line of symmetry of the second layer 210.
  • first reference line 715 and the second reference line 720 may be parallel or coincident with an edge 725 or line of symmetry of the second layer 210.
  • one or both of the first reference line 715 and the second reference line 720 may be rotated an angle relative to an edge 725 of the second layer 210.
  • an angle a may define the angle between the first reference line 715 and the second reference line 720.
  • the centroid of each of the first plurality of perforations 705 within a row may intersect a third reference line 730 running in a third direction.
  • the centroid of each of the second plurality of perforations 710 within a row may intersect a fourth reference line 735 running in a fourth direction.
  • a centroid refers to the center of mass of a geometric object. In the case of a substantially two dimensional object such as a linear slit, the centroid of the linear slit will be the midpoint.
  • the pattern of fluid passages 225 may also be characterized by a pitch, which indicates the spacing between corresponding points on fluid passages 225 within a pattern.
  • pitch may indicate the spacing between the centroids of fluid passages 225 within the pattern.
  • Some patterns may be characterized by a single pitch value, while others may be characterized by at least two pitch values. For example, if the spacing between centroids of the fluid passages 225 is the same in all orientations, the pitch may be characterized by a single value indicating the spacing between centroids in adjacent rows.
  • a pattern comprising a first plurality of perforations 705 and a second plurality of perforations 710 may be characterized by two pitch values, Pi and Pi, where Pi is the spacing between the centroids of each of the first plurality of perforations 705 in adjacent rows, and Pi is the spacing between the centroids of each of the second plurality of perforations 710 in adjacent rows.
  • each perforation within each row of the first plurality of perforations 705, each perforation may be separated from an adjacent perforation by a distance /) / . In some embodiments, within each row of the second plurality of perforations 710, each perforation may be separated from an adjacent perforation by a distance Di. In some patterns, the rows may be staggered. The stagger may be characterized by an orientation of corresponding points in successive rows relative to an edge or other reference line associated with the second layer 210. In some embodiments, the rows of the first plurality of perforations 705 may be staggered.
  • a fifth reference line 740 in a fifth direction runs through the centroids of corresponding perforations of adjacent rows of the first plurality of perforations 705.
  • the stagger of the rows of the first plurality of perforations 705 may be characterized by the angle b formed between the first reference line 715 and the fifth reference line 740.
  • the rows of the second plurality of perforations 710 may also be staggered.
  • a sixth reference line 745 in a sixth direction runs through the centroids of corresponding perforations of adjacent rows of the second plurality of perforations 710.
  • the stagger of the rows of the second plurality of perforations 710 may be characterized by the angle y formed between the first reference line 715 and the sixth reference line 745.
  • the second layer 210 may comprise a margin 750 having no perforations.
  • Figure 7 illustrates an example of a pattern that may be associated with some embodiments of the fluid passages 225.
  • each of the first plurality of perforations 705 and the second plurality of perforations 710 may be linear slots or slits.
  • the first reference line 715 may be parallel with an edge 725
  • the second reference line 720 may be orthogonal to the edge 725.
  • the third reference line 730 is orthogonal to the first reference line 715
  • the fourth reference line 735 is orthogonal to the second reference line 720.
  • the third reference line 730 may be incident with the centroids of corresponding perforations in alternating rows of the second plurality of perforations 710, and the fourth reference line 735 may intersect the centroids of corresponding perforations in alternating rows of the first plurality of perforations 705.
  • the fluid passages 225 are arranged in a cross-pitch pattern in which each of the first plurality of perforations 705 is orthogonal along its first long axis to each of the second plurality of perforations 710 along its second long axis.
  • Pi is equal to P2 (within acceptable manufacturing tolerances), and the cross-pitch pattern may be characterized by a single pitch value.
  • Li and 1 2 may be substantially equal, and / ) / and D2 may be also be substantially equal, all within acceptable manufacturing tolerances.
  • the rows of the first plurality of perforations 705 and the rows of the second plurality of perforations 710 may be characterized as staggered.
  • a may be about 90°
  • b may be about 135°
  • y may be about 45°
  • Pi may be about 4 mm
  • P2 may be about 4 mm
  • Li may be about 3 mm
  • L2 may be about 3 mm
  • / ) / may be about 5 mm
  • D2 may be about 5 mm.
  • Figure 8 is a schematic diagram of another example pattern that may be associated with some illustrative embodiments of the fluid passages 225.
  • each of the first plurality of perforations 705 and the second plurality of perforations 710 may be linear slits.
  • the first reference line 715 may be parallel with the edge 725, and the second reference line 720 may be orthogonal to the edge 725.
  • the third reference line 730 is orthogonal to the first reference line 715, and the fourth reference line 735 is orthogonal to the second reference line 720.
  • the third reference line 730 does not intersect or touch any of the second plurality of perforations 710, and the fourth reference line 735 may intersect the centroids of corresponding perforations in alternating rows of the first plurality of perforations 705.
  • the third reference line 730 may be equidistant from the centroids of corresponding adjacent perforations within each row of the second plurality of perforations 710.
  • the pattern of Figure 8 may also be characterized as a cross-pitch pattern, in which Pi is not equal to Pi. In the example of Figure 8, Pi is larger than Pi. Additionally, Li, l.i. Di, and D2 are substantially equal in the example of Figure 8.
  • a may be about 90°
  • b may be about 0° such that the first reference line 715 is coincident with the fifth reference line 740
  • y may be about 90°
  • Pi may be about 6 mm
  • P2 may be about 3 mm
  • Li may be about 3 mm
  • L2 may be about 3 mm
  • / / may be about 3 mm
  • D2 may be about 3 mm.
  • Figure 9 illustrates an additional example of a pattern that can be associated with some embodiments of the fluid passages 225.
  • each of the first plurality of perforations 705 and the second plurality of perforations 710 may be linear slits.
  • the first reference line 715 may be parallel with an edge 725
  • the second reference line 720 may be orthogonal to an edge 725.
  • the third reference line 730 is orthogonal to the first reference line 715
  • the fourth reference line 735 is orthogonal to the second reference line 720.
  • the third reference line 730 does not intersect or touch any of the second plurality of perforations 710
  • the fourth reference line 735 does not intersect or touch any of the first plurality of perforations 705.
  • the third reference line 730 may be equidistant from the centroids of corresponding adjacent perforations within each row of the second plurality of perforations 710
  • the fourth reference line 735 may be equidistant from the centroids of corresponding adjacent perorations within each row of the first plurality of perforations 705.
  • the pattern of Figure 9 may be characterized as a cross-pitch pattern, in which Pi is substantially equal to P2. Additionally, Li, L2, Di, and D2 are substantially equal in the example of Figure 11.
  • a may be about 90°
  • b may be about 0° such that the first reference line 715 is coincident with the fifth reference line 740
  • y may be about 90°
  • Pi may be about 6 mm
  • P2 may be about 6 mm
  • Li may be about 3 mm
  • L2 may be about 3 mm
  • / / may be about 3 mm
  • D2 may be about 3 mm.
  • Figure 10 illustrates additional embodiments of a pattern that may be associated with some embodiments of the fluid passages 225.
  • each of the first plurality of perforations 705 and the second plurality of perforations 710 may be linear slits.
  • the first reference line 715 may form an angle Q with an edge 725
  • the second reference line 720 may form an angle f an edge 725.
  • the third reference line 730 is orthogonal to the first reference line 715
  • the fourth reference line 735 is orthogonal to the second reference line 720.
  • the third reference line 730 does not intersect or touch any of the second plurality of perforations 710
  • the fourth reference line 735 does not intersect or touch any of the first plurality of perforations 705.
  • the third reference line 730 may be equidistant from the centroids of corresponding adjacent perforations within each row of the second plurality of perforations 710
  • the fourth reference line 735 may be equidistant from the centroids of corresponding adjacent perorations within each row of the first plurality of perforations 705.
  • the pattern of Figure 10 may be characterized as a cross-pitch pattern, in which Pi is substantially equal to P2.
  • Li may be substantially equal to 1, 2 - and / ) / may be substantially equal to /3 ⁇ 4 in the example of Figure 10.
  • b may be about 0° such that the first reference line 715 is coincident with the fifth reference line 740, y may be about 90°, Q may be about 45°, and f may be about 135°.
  • Figure 11 illustrates examples that may be associated with some embodiments of the fluid passages 225.
  • each of the first plurality of perforations 705 and the second plurality of perforations 710 may be linear slits.
  • the first reference line 715 may be parallel with an edge 725
  • the second reference line 720 may be orthogonal to an edge 725.
  • the third reference line 730 is orthogonal to the first reference line 715
  • the fourth reference line 735 is orthogonal to the second reference line 720.
  • the third reference line 730 may be incident with the centroids of corresponding perforations in alternating rows of the second plurality of perforations 710
  • the fourth reference line 735 may be incident with the centroids of corresponding perforations in alternating rows of the first plurality of perforations 705.
  • the centroid of each perforation of the first plurality of perforations 705 is incident with the centroid of a perforation of the second plurality of perforations 710.
  • the fluid passages 225 are arranged in a cross-pitch pattern in which each of the first plurality of perforations 705 is orthogonal along its first long axis to each of the second plurality of perforations 710 along its second long axis.
  • Pi is substantially equal to P2, and the cross-pitch pattern may be characterized by a single pitch value.
  • /. / and L2 may be substantially equal, and / ) / and D2 may be also be substantially equal, all within acceptable manufacturing tolerances.
  • the rows of the first plurality of perforations 705 and the rows of the second plurality of perforations 710 may be characterized as staggered.
  • a may be about 90°
  • b may be about 135°
  • y may be about 45°.
  • Figure 12 show additional embodiments associated with certain illustrative embodiments of the fluid passages 225.
  • each of the first plurality of perforations 705 and the second plurality of perforations 710 may be linear slits.
  • the first reference line 715 may form an angle Q with an edge 725.
  • the second reference line 720 may form an angle f with an edge 725.
  • the third reference line 730 and the fourth reference line 735 may be orthogonal to an edge 725.
  • the rows of the first plurality of perforations 705 and the rows of the second plurality of perforations 710 may be characterized as mirrored rows running in one direction parallel with an edge 725 of the second layer 210.
  • Li and l.i may be substantially equal, / ) / and D2 may be substantially equal, and Pi and P2 may be substantially equal, within acceptable manufacturing tolerances.
  • Q may be about 45°, and f may be about 135°.
  • the pattern of Figure 12 may be characterized as a herringbone pattern.
  • Figure 13 show additional example embodiments associated with certain illustrative embodiments of the fluid passages 225.
  • each of the first plurality of perforations 705 and the second plurality of perforations 710 may be curved slits.
  • the first reference line 715 may form an angle Q with an edge 725.
  • the second reference line 720 may form an angle f with an edge 725.
  • the third reference line 730 and the fourth reference line 735 may be parallel to an edge 725.
  • the rows of the first plurality of perforations 705 and the rows of the second plurality of perforations 710 may be characterized as mirrored rows running in one direction parallel with an edge 725 of the second layer 210.
  • the rows of the first plurality of perforations 705 and the rows of the second plurality of perforations 710 may be characterized as in an embodiment of Figure 13.
  • Li and 1, 2 may be substantially equal, / ) / and /3 ⁇ 4 may be substantially equal, and Pi and P2 may be substantially equal, within acceptable manufacturing tolerances.
  • Q may be about 45°, and f may be about 225°.
  • FIG 14 shows additional embodiments associated with certain embodiments of the fluid passages 225.
  • each of the first plurality of perforations 705 and the second plurality of perforations 710 may be characterized as chevron slits.
  • Each chevron slit may be formed from two orthogonal linear slits of the same length coincident at an endpoint.
  • the chevron slit may be characterized as pointing in the direction defined by the vector drawn from the centroid of the chevron slit to the coincident endpoints.
  • the chevron slits point in the same direction.
  • the chevron slits point in the same direction.
  • the chevron slits of the first plurality of perforations 705 and the chevron slits of the second plurality of perforations 710 point in opposite directions.
  • the first reference line 715 and the second reference line 720 may be parallel with an edge 725.
  • the third reference line 730 and the fourth reference line 735 may be orthogonal to the first reference line 715.
  • the rows of the first plurality of perforations 705 and the rows of the second plurality of perforations 710 may be characterized as mirrored rows running in one direction orthogonal to an edge 725 of the second layer 210.
  • Figure 15 further illustrates example embodiments that may be associated with some embodiments of the fluid passages 225.
  • Certain patterns of the fluid passages 225 may comprise a third plurality of perforations 1505, a fourth plurality of perforations 1510, a fifth plurality of perforations 1515, and a sixth plurality of perforations 1520.
  • Each of the third plurality of perforations 1505 may be a linear slit substantially orthogonal along a long axis to the edge 725.
  • Each of the fourth plurality of perforations 1510 may be a linear slit substantially orthogonal to the long axis of third plurality of perforations 1505 along a long axis.
  • Each of the fifth plurality of perforations 1515 may be a curved slit with its long axis rotated to form a 45° angle with the edge 725.
  • Each of the sixth plurality of perforations 1520 may be a curved slit with its long axis rotated to form a 225° angle with the edge 725.
  • the pattern of fluid passages 225 may be a repeating pattern of one of the fifth plurality of perforations 1515, one of the third plurality of perforations 1505, one of the sixth plurality of perforations, 1520, one of the fifth plurality of perforations 1515, one of the third plurality of perforations 1510, and one of the sixth plurality of perforations 1520, in sequence.
  • Each alternating row of the pattern of fluid passages 225 may be shifted three positions, in either direction.
  • Figures 16 through 18 are schematic diagrams illustrating additional details that may be associated with some embodiments of the fluid passages 225.
  • the fluid passages 225 may be distributed across the second layer 210 in a pattern of rows.
  • each fluid restriction 225 along a row may be rotated about 90° with respect to an adjacent fluid restriction 225.
  • Each fluid restriction 225 along a row may be rotated about 90° clockwise or 90° counterclockwise with respect to a preceding adjacent fluid restriction 225 in the row.
  • every second row may be offset by one fluid restriction 225 with respect to the previous row.
  • the pattern of Figures 16 through 18 may be characterized as a pattern of offset rows.
  • Example embodiments of the pattern of Figures 16 through 18 may additionally be characterized as a pattern of rotating fluid passages 225.
  • the second layer 210 may comprise a margin 750 having no perforations.
  • Figure 16 illustrates example embodiments where the fluid passages 225 comprise curved slits.
  • the fluid passages 225 within a row alternate between being parallel with an edge 725 of the second layer 210 along a long axis of the fluid restriction 225 and being orthogonal to an edge 725 of the second layer along the long axis.
  • Figure 17 shows some embodiments where the fluid passages 225 comprise chevron slits.
  • the fluid passages 225 within a row alternate between being parallel with an edge 725 of the second layer 210 along a long axis of the fluid restriction 225 and being orthogonal to an edge 725 of the second layer along the long axis.
  • Figure 18 further depicts illustrative embodiments where the fluid passages 225 comprise split-chevron slits.
  • Each split-chevron slit may be formed from two orthogonal non-incidental linear slits mirrored about an axis bisecting the angle formed by the intersection of the orthogonal long axis of the linear slits.
  • the fluid passages 225 within a row alternate between being parallel with an edge 725 of the second layer 210 along a long axis of the fluid restriction 225 and being orthogonal to an edge 725 of the second layer along the long axis.
  • Pi may be in a range of about 4 millimeters to about 6 millimeters, Pi may be in a range of about 3 mm to about 6 mm. In illustrative embodiments, / ) / may be in a range of about 3 mm to about 5 mm, and D2 may be in a range of about 3 mm to 5 mm. In some embodiments, the margin 750 may comprise between about 30% to about 80% of the total surface area of the second layer 210. In some embodiments, there may be an equal number of fluid passages 225 in the first plurality of perforations 705 as the number of fluid passages 225 in the second plurality of perforations 710.
  • Figure 19 is a schematic view of an example configuration of the apertures 240, illustrating additional details that may be associated with some embodiments of the third layer 215.
  • the apertures 240 are generally circular and have a diameter d . which may be about 6 millimeters to about 8 millimeters in some embodiments. A diameter d 4 of about 7 millimeters may be particularly suitable for some embodiments.
  • Figure 19 also illustrates an example of a uniform distribution pattern of the apertures 240.
  • the apertures 240 are distributed across the third layer 215 in a grid of parallel rows and columns. Within each row and column, the apertures 240 may be equidistant from each other, as illustrated in the example of Figure 19.
  • Figure 19 illustrates one example configuration that may be particularly suitable for many applications, in which the apertures 240 are spaced a distance ds apart along each row and column, with an offset of d 4 ,.
  • the distance ds may be about 9 millimeters to about 10 millimeters
  • the offset dr may be about 8 millimeters to about 9 millimeters.
  • Figure 20 is a schematic view of the apertures 240 in the example of Figure 19 overlaid on the second layer 210 of Figure 6, illustrating additional details that may be associated with some example embodiments of the tissue interface 120.
  • more than one of the fluid passages 225 may be aligned, overlapping, in registration with, or otherwise fluidly coupled to the apertures 240 in some embodiments.
  • one or more of the fluid passages 225 may be only partially registered with the apertures 240.
  • the apertures 240 in the example of Figure 20 are generally sized and configured so that at least four of the fluid passages 225 is registered with each one of the apertures 240.
  • one or more of the fluid passages 225 may be registered with more than one of the apertures 240.
  • any one or more of the fluid passages 225 may be a perforation or a fenestration that extends across two or more of the apertures 240. Additionally or alternatively, one or more of the fluid passages 225 may not be registered with any of the apertures 240.
  • the apertures 240 may be sized to expose a portion of the second layer 210, the fluid passages 225 , or both through the third layer 215.
  • the apertures 240 in the example of Figure 8 are generally sized to expose more than one of the fluid passages 225. Some or all of the apertures 240 may be sized to expose two or three of the fluid passages 225.
  • the length of each of the fluid passages 225 may be substantially smaller than the diameter of each of the apertures 240. More generally, the average dimensions of the fluid passages 225 are substantially smaller than the average dimensions of the apertures 240.
  • the apertures 240 may be elliptical, and the length of each of the fluid passages 225 may be substantially smaller than the major axis or the minor axis. In some embodiments, though, the dimensions of the fluid passages 225 may exceed the dimensions of the apertures 240, and the size of the apertures 240 may limit the effective size of the fluid passages 225 exposed to the lower surface of the dressing 110.
  • FIG. 1 illustrates an example embodiment of the dressing 110 in use on a tissue site.
  • the cover 125, the first layer 205, the second layer 210, the third layer 215, or various combinations may be assembled before application or in situ.
  • the second layer 210 may be laminated to the first layer 205 in some embodiments.
  • the cover 125 may be disposed over the first layer 205 and coupled to the third layer 215 around the first layer 205 in some embodiments.
  • one or more layers of the tissue interface 120 may be coextensive.
  • the second layer 210 may be cut flush with the edge of the first layer 205.
  • the dressing 110 may be provided as a single, composite dressing.
  • the third layer 215 may be coupled to the cover 125 to enclose the first layer 205 and the second layer 210, wherein the third layer 215 may be configured to face a tissue site.
  • tissue site in this context broadly refers to a wound or defect located on or within tissue, including but not limited to, bone tissue, adipose tissue, muscle tissue, neural tissue, dermal tissue, vascular tissue, connective tissue, cartilage, tendons, or ligaments.
  • a wound may include chronic, acute, traumatic, subacute, and dehisced wounds, partial-thickness bums, ulcers (such as diabetic, pressure, or venous insufficiency ulcers), flaps, and grafts, for example.
  • tissue site and/or “surface tissue site” in this context may also refer to areas of tissue that are not necessarily wounded or defective, but are instead areas in which it may be desirable to add or promote the growth of additional tissue. For example, negative pressure may be used in certain tissue areas to grow additional tissue that may be harvested and transplanted to another tissue location.
  • the tissue site 2105 may be a surface wound that extends through the epidermis 2110 and into a dermis 2115. In some examples, the tissue site 2105 may extend through the epidermis 2110 and dermis 2115 and into subcutaneous tissue 2120.
  • the second layer 210, the third layer 215, or both may be interposed between the first layer 205 and the tissue site 2105, which can substantially reduce or eliminate adverse interaction between the first layer 205 and the tissue site 2105.
  • the third layer 215 may be placed over a surface wound (including edges of the wound) and undamaged epidermis to prevent direct contact with the first layer 205.
  • the treatment aperture 235 of the third layer 215 may be positioned adjacent to, proximate to, or covering a tissue site 2105.
  • at least some portion of the second layer 210, the fluid passages 225, or both may be exposed to a tissue site 2105 through the treatment aperture 235, the apertures 240, or both.
  • the periphery 230 of the third layer 215 may be positioned adjacent to or proximate to tissue around or surrounding the tissue site 2105.
  • the third layer 215 may be sufficiently tacky to hold the dressing 110 in position, while also allowing the dressing 110 to be removed or re-positioned without trauma to the tissue site 2105.
  • Removing the release liner 265 can also expose the adhesive 260, and the cover 125 may be attached to an attachment surface, such as the periphery 230 or other area around the treatment aperture 235 and the first layer 205.
  • the adhesive 260 may also be attached to epidermis peripheral to a tissue site 2105, around the first layer 205 and the second layer 210.
  • the adhesive 260 may be in fluid communication with an attachment surface through the apertures 240 in at least the periphery 230 of the third layer 215.
  • the adhesive 260 may also be in fluid communication with the edges 250 through the apertures 240 exposed at the edges 250.
  • the adhesive 260 may be pressed through the apertures 240 to bond the dressing 110 to the attachment surface.
  • the apertures 240 at the edges 250 may permit the adhesive 260 to flow around the edges 250 for enhancing the adhesion of the edges 250 to an attachment surface.
  • the apertures 240 may be sized to control the amount of the adhesive 260 exposed through the apertures 240.
  • the relative sizes of the apertures 240 may be configured to maximize the surface area of the adhesive 260 exposed and in fluid communication through the apertures 240 at the comers 245.
  • the edges 250 may intersect at substantially a right angle, or about 90 degrees, to define the comers 245.
  • the comers 245 may have a radius of about 10 millimeters.
  • three of the apertures 240 may be positioned in a triangular configuration at the comers 245 to maximize the exposed surface area for the adhesive 260.
  • the size and number of the apertures 240 in the comers 245 may be adjusted as necessary, depending on the chosen geometry of the comers 245, to maximize the exposed surface area of the adhesive 260.
  • the apertures 240 at the comers 245 may be fully contained within the third layer 215, substantially precluding fluid communication in a lateral direction exterior to the comers 245.
  • the apertures 240 at the comers 245 being fully contained within the third layer 215 may substantially preclude fluid communication of the adhesive 260 exterior to the comers 245, and may provide improved handling of the dressing 110 during deployment at a tissue site 2105.
  • the exterior of the comers 245 being substantially free of the adhesive 260 may increase the flexibility of the comers 245 to enhance comfort.
  • the bond strength of the adhesive 260 may vary based on the configuration of the third layer 215.
  • the bond strength may vary based on the size of the apertures 240.
  • the bond strength may be inversely proportional to the size of the apertures 240.
  • the bond strength may vary in different locations, for example, if the size of the apertures 240 varies. For example, a lower bond strength in combination with larger apertures 240 may provide a bond comparable to a higher bond strength in locations having smaller apertures 240.
  • Figure 21A illustrates the adhesive 260 of Figure 21 prior to coming in contact with the epidermis 2110.
  • the third layer 215 may be formed of a silicone polymer or polyurethane material, which may form sealing couplings 2125 with the epidermis 2110.
  • the bond strength or tackiness of the sealing couplings 2125 may have a peel adhesion or resistance to being peeled form a stainless steel material between about 0.5N/25mm to about 1.5N/25mm on stainless steel substrate at 23° C at 50% relative humidity based on ASTM D3330.
  • the third layer 215 may achieve this bond strength after a contact time of less than 60 seconds.
  • Tackiness may be considered a bond strength of an adhesive after a very low contact time between the adhesive and a substrate.
  • the third layer 215 may have a thickness 2130 in a range of about 200 microns to about 1000 microns. In the assembled state, the third layer 215 may be coupled to the epidermis 2110. If the third layer 215 is placed proximate to or in contact with the epidermis 2110, the third layer 215 may form sealing couplings 2125 with the epidermis 2110. In some embodiments, the thickness 2130 of the third layer 215 may create a gap 2135 between the adhesive 260 and the epidermis 2110.
  • Figure 21B illustrates the adhesive 260 of Figure 21A in contact with the epidermis 2110.
  • pressure may be applied to the cover 125, which may cause the adhesive 260 to be pressed at least partially into contact with epidermis 2110 to form bonding couplings 2140.
  • the bonding couplings 2140 may provide secure, releasable mechanical fixation to the epidermis 2110.
  • the sealing couplings 2125 between the third layer 215 and the epidermis 2110 may not be as mechanically strong as the bonding couplings 2140 between the adhesive 260 and the epidermis 2110.
  • the bonding couplings 2140 may also anchor the dressing 110 to the epidermis 2110, inhibiting migration of the dressing 2110.
  • the geometry and dimensions of the tissue interface 120, the cover 125, or both may vary to suit a particular application or anatomy.
  • the geometry or dimensions of the tissue interface 120 and the cover 125 may be adapted to provide an effective and reliable seal against challenging anatomical surfaces, such as an elbow or heel, at and around a tissue site 2105.
  • the dimensions may be modified to increase the surface area for the third layer 215 to enhance the movement and proliferation of epithelial cells at a tissue site 2105 and reduce the likelihood of granulation tissue in-growth.
  • the dressing 110 can provide a sealed therapeutic environment proximate to a tissue site 2105, substantially isolated from the external environment, and the negative-pressure source 105 can reduce the pressure in the sealed therapeutic environment.
  • the treatment aperture 235 can provide an open area for delivery of negative pressure and passage of wound fluid through the second layer 210 and the first layer 205.
  • the third layer 215 may provide an effective and reliable seal against challenging anatomical surfaces, such as an elbow or heel, at and around a tissue site 2105.
  • the dressing 110 may permit re-application or re-positioning, to correct air leaks caused by creases and other discontinuities in the dressing 110, for example. The ability to rectify leaks may increase the efficacy of the therapy and reduce power consumption in some embodiments.
  • Some embodiments of the pattern of fluid passages 225 may permit the dressing 110 to deform to a greater degree while simultaneously conforming more closely over tissue sites 2105 having large surface area with complex contours. By facilitating uniform expansion profiles and forces in more than one direction, the dressing 110 can deform and apply forces in a uniform manner radially. This may permit the dressing 110 to manage deeper wounds and large, complex wounds such as venous leg ulcerations and diabetic foot ulcers.
  • the fluid passages 225 may facilitate the treatment of wounds with a diameter which may be greater than about 1.3 times the depth of the wound, and may allow more extension of the dressing 110 when applied to deeper wounds.
  • the MVTR, vapor-permeable and fluid-impermeable characteristics of the second layer 210, and the even expansion characteristics of the pattern of fluid restrictions 225 may be beneficial in delivering negative pressure to all areas covered by the second layer 210.
  • the second layer 210 may prevent liquid flow through the unperforated regions of the second layer 210, but allows air, gas, and pressure to manifold.
  • the micropores 220 in the second layer 210 may permit the delivery of negative pressure in the unperforated regions of the second layer 210 and allow very small quantities of liquid at the micro level to be removed through the second layer 210.
  • the micropores 220 comprise a width or an average diameter in a range of about 0.4 microns to about 10 microns, very small quantities of liquid may be removed through the micropores 220.
  • the dressing interface 275 may be disposed over the aperture 280 and attached to the cover 125.
  • the fluid conductor 270 may be fluidly coupled to the dressing interface 275 and to the negative-pressure source 105.
  • Negative pressure applied through the tissue interface 120 can create a negative pressure differential across the fluid passages 225 in the second layer 210, which can open or expand the fluid passages 225.
  • the fluid passages 225 may comprise substantially closed fenestrations through the second layer 210
  • a pressure gradient across the fenestrations can strain the adjacent material of the second layer 210 and increase the dimensions of the fenestrations to allow liquid movement through them, similar to the operation of a duckbill valve. Opening the fluid passages 225 can allow exudate and other liquid movement through the fluid passages 225 into the first layer 205.
  • the first layer 205 can provide passage of negative pressure and wound fluid, which can be collected in the container 115.
  • Changes in pressure can also cause the first layer 205 to expand and contract, and the second layer 210, the third layer 215, or both may protect the epidermis from irritation that could be caused by expansion, contraction, or other movement of the first layer 205.
  • the overlay margin 415 may be disposed between the first layer 205 and epidermis around a tissue site 2105.
  • the second layer 210 and the third layer 215 can also substantially reduce or prevent exposure of a tissue site 2105 to the first layer 205, which can inhibit growth of tissue into the first layer 205.
  • the second layer 210 may cover the treatment aperture 235 to prevent direct contact between the first layer 205 and a tissue site 2105.
  • a filler may also be disposed between a tissue site 2105 and the third layer 215.
  • a tissue site 2105 is a surface wound
  • a wound filler may be applied interior to the periwound
  • the third layer 215 may be disposed over the periwound and the wound filler.
  • the filler may be a manifold, such as an open-cell foam.
  • the filler may comprise or consist essentially of the same material as the first layer 205 in some embodiments.
  • instillation solution or other fluid may be distributed to the dressing 110, which can increase the pressure in the tissue interface 120.
  • the increased pressure in the tissue interface 120 can create a positive pressure differential across the fluid passages 225 in the second layer 210, which can open the fluid passages 225 to allow the instillation solution or other fluid to be distributed to the tissue site 2105.
  • the systems, apparatuses, and methods described herein may provide significant advantages.
  • some dressings for negative-pressure therapy can require time and skill to be properly sized and applied to achieve a good fit and seal.
  • some embodiments of the dressing 110 provide a negative-pressure dressing that is simple to apply, reducing the time to apply and remove.
  • the dressing 110 may be a fully-integrated negative-pressure therapy dressing that can be applied to a tissue site 2105 (including on the periwound) in one step, without being cut to size, while still providing or improving many benefits of other negative-pressure therapy dressings that require sizing.
  • Such benefits may include good manifolding, beneficial granulation, protection of the peripheral tissue from maceration, protection of the tissue site 2105 from shedding materials, and a low-trauma and high-seal bond. These characteristics may be particularly advantageous for surface wounds having moderate depth and medium -to-high levels of exudate.
  • Some embodiments of the dressing 110 may remain on the tissue site 2105 for at least 5 days, and some embodiments may remain for at least 7 days.
  • Antimicrobial agents in the dressing 110 may extend the usable life of the dressing 110 by reducing or eliminating infection risks that may be associated with extended use, particularly use with infected or highly exuding wounds.

Abstract

La présente invention concerne un pansement destiné à traiter un site tissulaire par pression négative, pouvant comprendre un élément de recouvrement muni d'un adhésif, un collecteur, un film polymère perforé comprenant des micropores, et un gel de silicone perforé ayant une ouverture de traitement. L'élément de recouvrement, le collecteur, le film polymère perforé et le gel de silicone perforé peuvent être assemblés par empilement, l'élément de recouvrement et le gel de silicone perforé entourant le collecteur. Le film polymère perforé peut être au moins partiellement rendu visible à travers l'ouverture de traitement, et au moins une partie de l'adhésif peut être rendue visible à travers la silicone perforée autour de l'ouverture de traitement.
PCT/IB2021/050343 2020-01-20 2021-01-18 Systèmes formant interface avec la plaie mettant en oeuvre des couches microporeuses pour la gestion des liquides WO2021148924A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US202062963425P 2020-01-20 2020-01-20
US62/963,425 2020-01-20

Publications (1)

Publication Number Publication Date
WO2021148924A1 true WO2021148924A1 (fr) 2021-07-29

Family

ID=74194803

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB2021/050343 WO2021148924A1 (fr) 2020-01-20 2021-01-18 Systèmes formant interface avec la plaie mettant en oeuvre des couches microporeuses pour la gestion des liquides

Country Status (1)

Country Link
WO (1) WO2021148924A1 (fr)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018226667A1 (fr) * 2017-06-07 2018-12-13 Kci Licensing, Inc. Pansements composites personnalisables destinés à un traitement par pression négative à granulation améliorée et à macération réduite
WO2018226687A1 (fr) * 2017-06-07 2018-12-13 Kci Licensing, Inc. Procédés de fabrication et d'assemblage d'une interface tissulaire à deux matériaux pour une thérapie par pression négative

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018226667A1 (fr) * 2017-06-07 2018-12-13 Kci Licensing, Inc. Pansements composites personnalisables destinés à un traitement par pression négative à granulation améliorée et à macération réduite
WO2018226687A1 (fr) * 2017-06-07 2018-12-13 Kci Licensing, Inc. Procédés de fabrication et d'assemblage d'une interface tissulaire à deux matériaux pour une thérapie par pression négative

Similar Documents

Publication Publication Date Title
EP3634339B1 (fr) Pansement à décollement et placement pour thérapie par pression négative
US11179275B2 (en) Methods for manufacturing and assembling dual material tissue interface for negative-pressure therapy
EP3634333B1 (fr) Pansement pour exsudat épais et instillation
US20200121509A1 (en) Peel and place dressing having a closed-cell contact layer
WO2019136164A1 (fr) Pansement à décoller et à positionner pour exsudat épais et instillation
EP3958808B1 (fr) Pansement transparent à décollement et placement pour thérapie par pression négative
US20220249762A1 (en) Composite Dressing For Tissue Closure With Negative Pressure
US20220241116A1 (en) Customizable Dressings For Negative-Pressure Treatment Of Large Areas
US20210077302A1 (en) Peel And Place Dressing For Thick Exudate And Instillation
WO2021148925A1 (fr) Interface tissulaire à pression négative adaptable avec protection des bords
WO2021148924A1 (fr) Systèmes formant interface avec la plaie mettant en oeuvre des couches microporeuses pour la gestion des liquides
EP3735211B1 (fr) Pansement à décoller et à positionner pour exsudat épais et instillation
WO2023170508A1 (fr) Pansements et systèmes améliorés pour traitement de plaies par pression négative et traitement par infusion avec collecteurs à faible volume et conduite d'infusion de dérivation

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 21701175

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 21701175

Country of ref document: EP

Kind code of ref document: A1