CN111050711A - Anti-deformation wound treatment devices and related methods of use - Google Patents

Abstract

A wound treatment apparatus is disclosed that may include a wound interface sealably secured to a skin surface surrounding a wound bed for enclosing the wound bed within a fluid-tight enclosure. The fluid can be in communication with the enclosed space for a pressure range p_min≤p₀≤p_maxPeriodically varying the pressure p in the enclosed space₀. When the pressure p in the enclosed space₀Less than ambient pressure p_ambThe wound interface may have sufficient resistance to deformation to expand at least a portion of the wound bed into the enclosed space. The wound treatment apparatus may include a pad receivable within the enclosed space, the pad being in communication with the expanded wound bed for absorbing exudate from the expanded wound bed. Related methods of use of the wound treatment apparatus are also disclosed.

Description

Anti-deformation wound treatment devices and related methods of use

Cross reference to related applications

This application claims priority from the following patent applications: us patent application No. 15/663,708 filed on 29.7.7.2017, us patent application No. 15/663,709 filed on 29.7.7.7.7. 15/663,710 filed on 29.7.7.2017, us patent application No. 15/663,713 filed on 29.7.7.2017, and us patent application No. 15/663,714 filed on 29.7.7.2017. All priority-claims patent applications are hereby incorporated by reference in their entirety as if fully set forth herein.

Background

Technical Field

The present disclosure relates to medical devices, and more particularly, to apparatus for wound therapy and related methods.

Background

The wound bed, as referred to herein, comprises a localized area of tissue that is affected by adverse factors, resulting in, for example, cellular abnormalities such as swelling, inflammation, degeneration, infection, or cell death. The wound bed may contain underlying tissue and structures that are exposed to varying degrees, with possible infection and tissue changes. The wound bed represents an unhealed wound. By contrast, a healing wound is meant a skin surface that was previously wounded, but now has its major gap completely closed and covered by a varying amount of epidermal and scar tissue. The wound bed may be located within a wound boundary that extends along the affected area at the skin surface of the skin. The wound bed may continue deep into the dermis and the wound bed may extend deeper, for example, into subcutaneous fat and deeper tissue. Thus, the wound bed may include damaged flaps, sinuses, tracts, and fistulas, as well as surrounding affected tissue. Fig. 1 illustrates a complex wound bed including some of the anatomical structures involved therein. Wound boundary, as referred to herein, refers to the perimeter of the wound bed at the skin surface of the skin.

For example, a wound may require a long time to heal due to impaired blood circulation and hypoxia of the tissue. In 2012, based on a study at the us wound registry, reimbursement data for 5240 trauma patients and 7099 wounds was analyzed, and it was determined that the cost of treating 640 million wounds in the us would reach an alarming $ 500 billion, more than twice the previous estimate, which costs 10 times the world health organization's budget. 65.8% of wounds had an average healing time of 15 weeks, and 10% of wounds had a healing time of 33 weeks or more. Nearly 8 million amputations occur in the united states each year, each amputation potentially representing failure of expensive treatment for many months or even years.

Current Negative Pressure Wound Therapy (NPWT) devices may include a dressing filled into a wound bed, a polymeric elastic film that is entirely fluid impermeable and back-covered with an adhesive, and a drainage tube in fluid communication with the dressing. Clinically commonly used membranes, often referred to as "occlusive" or even "semi-permeable", it is understood that its permeability is usually limited to evaporation (allowing the skin to "breathe") and fluid cannot pass through. The dressing may be, for example, cotton gauze, or an open-cell foam made of polyethylene or polyurethane.

After the wound bed is filled with dressing, the film may be centered over the dressing and wound bed, and then the seal adhesively secured to the skin surrounding the wound bed to seal the wound bed and dressing. Finally, a hole is created in the film above the dressing, to which the adapter and the drainage tube are sealingly connected. Air in the region between the membrane and the wound bed is drawn through the tube to create a pressure p less than atmospheric in the region_ambNegative pressure p of_s. Due to the pressure in the region passing through the negative pressure p_sAnd decreases, causing the atmospheric pressure to press the film and dressing against the wound bed, which shrinks with the surrounding skin. Exudate from the wound bed may be drawn through the dressing and directed out through the drainage tube.

However, current NPWT apparatus have various disadvantages. For example, because the dressing overlaps normal skin, which may result in maceration of the normal skin, the dressing must be trimmed to conform to the precise geometry of the wound bed. Undetected dressing fragments and trimmed dressing fragments in the wound may lead to infection of the lesion. Dressings may require frequent replacement, usually every other day, each dressing replacement may be extremely painful, such distress resulting in the need for a stronger analgesic or local anesthetic as a preoperative medication prior to dressing replacement. The dressing is in constant contact with the wound bed and the granulation tissue required may be due to the negative pressure p_sAnd is absorbed into the micro-crevices of the dressing, which can tear or damage granulation tissue each time the dressing is changed, resulting in repeated frustration of the healing process. Furthermore, dressing changes are expensive in terms of time, medical personnel and consumables.

Because of the negative pressure p_sThe negative pressure p on the wound bed is achieved by different thicknesses of the dressing and different distances from the drainage tube position_sMay be non-uniform. This uneven negative pressure distribution, as well as the uneven pressure resulting from a dressing of the same thickness being pressed into a wound bed of uneven thickness, may be an obvious significant cause of reduced blood flow near the wound boundary of the wound bed. (see, e.g., Borgquist, O., R. Ingemansson, M. for example

Effects of negative pressure on thermal on regional flow, wuondlinkage and fluid removal- -Examining low pressure levels, intermittentandible thermal, the "annual clinical treatise on skin and wound care progression of St.Andoni, Tex." -10 months, 22 days-25 days 2009). Reduced blood flow within the wound boundary may prevent healing of the wound bed, as healing is usually a decrease in the wound bed from the periphery to the center. For example, in a wound bed of severe potential vascular lesions, such as may be found in advanced diabetes, due to the negative pressure p_sCompressing the capillaries in the wound bed, current NPWT devices may not be able to sufficiently increase blood flow, although the goal of the NPWT device is to increase blood flow.

Drainage of wound bed exudate can also be problematic in current NPWT devices, as protein rich exudate from the wound bed may remain in the dressing and drainage tubes, often leading to occlusion of the aspiration system, pressure display errors, and abnormal cessation of NPWT therapy.

Furthermore, current NPWT devices can only be used after initial cleaning and debridement, and may not be used at the final stages of wound healing because the presence of the dressing, acting as a foreign body in the wound bed, may prevent complete closure of the wound bed.

Accordingly, there is a need for improved devices for wound treatment and related methods of wound treatment.

Disclosure of Invention

These and other needs and disadvantages are met and overcome by the wound treatment devices and associated methods of use disclosed herein. Additional modifications and advantages may be recognized by those skilled in the art upon studying this disclosure. A wound treatment device is disclosed herein. In various aspects of the invention, a wound treatment apparatus may comprise a wound interface sealably secured to a skin surface surrounding a wound bed to form an enclosed space through a fluid-tight wound interface to treat a woundThe wound boundary of the oral bed is enclosed within the enclosed space. When the pressure p in the enclosed space₀Less than ambient pressure p_ambThe wound interface may have sufficient resistance to deformation to expand at least a portion of the wound bed into the enclosed space. In various aspects of the invention, the wound treatment apparatus may include a port disposed about the wound interface for fluid communication with the enclosed space to vary the pressure p within the enclosed space when the wound interface is sealingly secured to the skin surface₀In the pressure range p_min≤p₀≤p_maxPeriodically circulating in the inner circle. In various aspects of the invention, the wound treatment apparatus may comprise a pad positionable within the enclosed space for absorbing exudates from the wound bed. In various aspects of the invention, the pressure p is such that when the wound interface is sealingly secured to the skin surface surrounding the wound bed₀The change in pressure causes the wound bed to expand into contact with the pad placed within the enclosed space, and the change in pressure p0 causes the wound bed to move out of contact with the pad placed within the enclosed space. Also disclosed herein are related methods of use of the wound treatment devices.

This summary provides a basic explanation of some aspects of the apparatus and methods disclosed herein, as a prelude to the detailed description that follows. Thus, this summary is not intended to identify key elements or to delineate the scope of the apparatus and methods disclosed herein.

Drawings

FIG. 1 depicts a cross-sectional view of an exemplary wound bed with erosion, wound tunnels, and fistulas

FIG. 2A illustrates a cross-sectional view of an exemplary implementation of a wound treatment apparatus;

FIG. 2B illustrates, in an enlarged cross-sectional view, a circled area of an exemplary implementation of the wound treatment apparatus shown in FIG. 2A;

FIG. 3 illustrates a perspective view of a second exemplary implementation of a wound treatment apparatus;

fig. 4A illustrates, in perspective view, a portion of the exemplary wound treatment apparatus of fig. 3;

FIG. 4B illustrates, by an exploded view, a portion of the exemplary wound treatment apparatus of FIG. 3;

fig. 5A illustrates a cross-sectional view of a portion of the exemplary wound treatment apparatus of fig. 3 at a first stage of exemplary operation.

Fig. 5B illustrates a cross-sectional view of a portion of the exemplary wound treatment apparatus of fig. 3 in a second stage of exemplary operation;

FIG. 6 illustrates a perspective view of a third exemplary implementation of a wound treatment apparatus;

fig. 7A illustrates a cross-sectional view of a portion of the exemplary wound treatment apparatus of fig. 6 at a first stage of exemplary operation.

FIG. 7B illustrates a cross-sectional view of a portion of the exemplary wound treatment apparatus of FIG. 6 in a second stage of exemplary operation;

FIG. 8 illustrates a cross-sectional view of a fourth exemplary implementation of a wound treatment apparatus;

fig. 9 illustrates a cross-sectional view of a fifth exemplary implementation of a wound treatment apparatus;

FIG. 10 illustrates a cross-sectional view of a sixth exemplary implementation of a wound treatment apparatus;

FIG. 11A illustrates a cross-sectional view of a portion of a seventh exemplary implementation of a wound treatment apparatus at a first stage of operation;

FIG. 11B illustrates a cross-sectional view of a portion of the exemplary implementation of the wound treatment apparatus of FIG. 11A in a second stage of operation;

fig. 12 illustrates a cross-sectional view of an eighth exemplary implementation of a wound treatment apparatus;

fig. 13A illustrates a cross-sectional view of a ninth exemplary implementation of a wound treatment apparatus;

fig. 13B illustrates a cross-sectional view of a portion of the exemplary implementation of the wound treatment apparatus of fig. 13A.

Fig. 14 illustrates a schematic diagram of a tenth exemplary implementation of a wound treatment apparatus; and the combination of (a) and (b),

fig. 15 illustrates a flow diagram of an exemplary method of using a wound treatment apparatus.

The illustrations are exemplary only, and the embodiments illustrated herein have been chosen for ease of explanation. The numbers, locations, relationships, and dimensions of the elements shown in the drawings are explained herein to constitute different embodiments described herein, as are the various dimensions and dimensional ratios to meet specific force, weight, strength, flow, and the like requirements, or the numbers, locations, relationships, and dimensions of these elements, as well as the various dimensions and dimensional ratios, will be readily understood by one of ordinary skill in the art after studying this disclosure. The same reference numbers may be used in different drawings to identify the same or similar elements. Furthermore, when the terms "top," "bottom," "right," "left," "front," "back," "first," "second," "inner," "outer," and similar terms are used, they should be understood with reference to the orientation of the embodiments shown in the drawings and utilized to facilitate the description thereof. Relative terms used herein, such as generally, approximately, substantially, may refer to engineering, manufacturing, or scientific tolerances, such as ± 0.1%, 1%, 2.5%, 5%, or other such tolerances, as would be readily understood by a worker of ordinary skill in the art after studying this disclosure.

Detailed Description

A wound treatment device and associated methods of use are disclosed herein. In various aspects of the invention, a wound treatment apparatus comprises a wound interface sealably secured to a skin surface surrounding a wound bed, a portion of the wound bed on the skin surface enclosed within an enclosed space by forming the enclosed space within a fluid-tight wound interface. At some time, when the pressure p in the enclosed space is₀Less than ambient pressure p_ambThe wound interface has sufficient resistance to deformation to expand at least a portion of the wound bed into the enclosed space. The wound interface may be functionally connected to other devices, from a manual source of negative pressure to a control module, which is capable of monitoring and interacting with various parameters within the enclosed space to deliver different treatments to the wound bed.

At times, a pad is provided in communication with the enclosed space to absorb exudate from the wound bedAnd (6) discharging. The wound treatment apparatus may include one or more ports for fluid communication with the enclosed space, the pressure p within the enclosed space being periodically varied by flowing gaseous fluid into or out of the enclosed space from the one or more ports₀In the pressure range p_min≤p₀≤p_maxAn internal variation. At some time, the pressure p₀The period of time for the periodic change may range from about 5 minutes (12 times per hour) to about 6 minutes (10 times per hour), or may be shorter or longer. Periodically changing pressure p in an enclosed space₀The wound bed and surrounding tissue may be massaged, for example, by suction pressure p₀＜p_ambExpanding the wound bed into the enclosed space, and at p₀≈p_ambWill be released from the wound bed expanded into the enclosed space to a baseline state, alternating.

Exudate as referred to herein includes, for example, proteinaceous liquids exuded from the wound bed, as well as various plasma and blood components. Exudate may also include other liquids used to treat wound beds.

Reference herein to fluid includes liquid, gas and combinations thereof. Liquids may include, for example, saline solutions, proteolytic enzyme solutions, antimicrobial lavage solutions, amniotic fluids, and exudates. The gas may include, for example, air, oxygen, nitric oxide, nitrogen, a therapeutic gas or an inert gas, and combinations thereof.

The term "fluid-tight" or related terms, as used herein, at times, refers to having sufficient leak-resistance to permit the creation of a pressure p in an enclosed space that may be above or below ambient pressure, by insufflation or vacuum suction_ambPressure p of₀. The term "fluid-tight" is sometimes used to refer to a material having sufficient resistance to leakage to substantially maintain fluid within the enclosed space, including gases and liquids, except by controlling fluid communication through one or more lumens that are in fluid communication with the enclosed space through the wound interface. At times, "fluid-tight" means having sufficient resistance to leakage to maintain a pressure p within the enclosed space₀Above or below ambient pressure p_amb。

Reference herein to ambient pressure p_ambRefers to the pressure of the area surrounding the wound treatment device. Ambient pressure p_ambFor example, atmospheric pressure, hull pressure where the wound treatment device is used, such as in an aircraft or submarine, or pressure substantially maintained within a building or other structure may be referred to. Ambient pressure p_ambMay differ, for example, due to altitude or weather conditions. Pressure p_minRefers to the minimum pressure achieved within the enclosed space of the wound treatment device; periodically changing pressure p₀Pressure change, varying pressure and similar terms refer to a time-varying pressure p within an enclosed space₀Is changed. Pressure p_maxRefers to the maximum pressure reached within the enclosed space of the wound treatment device.

The pad, as referred to herein, may comprise a series of exudate absorbing absorbent materials, including open cell foams comprised of materials such as polyvinyl alcohol (PVA), polyurethane or other polymeric foams. The pad may comprise a plurality of fibers, for example sodium carboxymethylcellulose fibers

Or a nonwoven fabric comprised of multicomponent fibers of nylon and polyester that have been subjected to a hydroentangling process

Split longitudinally into their individual components. The pad may comprise woven fibres, for example in a woven fabric, predominantly hydrophobic fibres on the outer surface and predominantly hydrophilic fibres on the inner side, to act as conduits for fluid transfer. The mat may also comprise a nonwoven fabric that has been wound together, cross-laid and/or twisted together into a suitable shape, such as a cylindrical shape or a ribbon shape of various sizes and thicknesses, with a plurality of linear channels formed between the fibers for flow guidance by capillary action. The hydrophobic fibers may be comprised of polyester and the hydrophilic fibers may be comprised of aliphatic or semi-aromatic polyamides (e.g., nylon). Polyester-polyurethane copolymerFibres (e.g. of the type

Or

) May additionally be combined with a fabric to impart stretchability and open-ended properties to the pad. The hydrophobic fibers may be remote from the liquid to prevent moisture accumulation, thereby causing maceration of the tissue with which they come into contact. The hydrophilic fibers may help transport fluid toward the exit port of the wound interface by capillary action.

Sometimes, as described herein, the wound interface has sufficient resistance to deformation to maintain a closed space when the pressure p is applied₀＜＜p_ambSufficient to draw the wound tissue toward the enclosed space until the enclosed space is occupied. At times, the wound interface has sufficient resistance to deformation to maintain the enclosed space through a pressure within the enclosed space that is less than the ambient pressure p_ambPressure p of₀Expanding at least a portion of the wound bed toward or into the enclosed space. At times, the wound interface has sufficient resistance to deformation to maintain an enclosed space above the wound bed by being sufficiently below ambient pressure p within the enclosed space_ambPressure p of₀Expanding at least a portion of the wound bed toward or into the enclosed space. At least a portion of the wound interface forming the enclosed space is, at times, substantially rigid. At all times, the wound interface has sufficient resistance to deformation, in the pressure range p_min≤p₀≤p_maxKeeping the seal fixed to the skin and fluid-tight.

The terms "distal" and "proximal," as used herein, are defined from the perspective of a healthcare provider when treating a patient with a wound therapy device. When treating a patient, the distal portion of the wound therapy device faces the patient and the proximal portion of the wound therapy device faces the physician. While the proximal portion of the structure may be the portion closest to the physician, the distal portion of the structure is the portion closest to the patient.

Massaging the wound bed by pressure changes, including the regular deformation of the wound bed volume, may be accompanied by an increase in blood flow. The terms massage, regular deformation, tissue deformation, wound bed expansion, are used interchangeably in this disclosure to refer to the general process of subjecting the wound bed to pressure fluctuations, and the resulting changes in the wound bed, including blood flow, blood oxygenation, cell tension, macroscopic and microscopic deformations, and other changes. Increased surging blood flow near the wound bed can lead to increased nutrients and immune elements, reduce infection and inflammation, and confer other beneficial effects that can promote wound bed healing. Massage of the wound bed may promote movement of exudate from the interstitial spaces of the wound to the wound crater outlet. This may reduce secondary edema caused by capillary compression and improve microcirculation in wounds and wounds. One of the at least one or more ports may be in fluid communication with the pad to allow transfer of exudate from the pad. Optionally, one of the at least one or more ports may be fluidly used to directly or indirectly monitor parameters within the enclosed space, such as pressure, temperature, humidity, pH, tissue oxygenation levels, blood flow, and the like, to achieve improved treatment.

Fig. 2A and 2B illustrate an exemplarywound treatment apparatus 1000. As shown in fig. 2A, the wound treatment device includes awound interface 1015 secured to askin surface 1011 forming anenclosed space 1017 to enclose awound bed 1013 within the enclosedspace 1017. As shown in fig. 2A, thewound interface 1015 includes acover 1002 that may have a degree of transparency from transparent to opaque, anannular base flange 1004, and one or more ports, such asport 1003 emanating from the wound interface. In this embodiment, the port is optional, for example for wound protection and humidification. As shown,port 1003 is in fluid communication with theenclosed space 1017 and can be connected to conduits in communication with various fluid sources or reservoirs for fluid communication between the fluid sources or reservoirs and theenclosed space 1017. Theport 1003 may be used to directly or indirectly monitor parameters within the enclosedspace 1017. Theport 1003, for example, may be connected to a source of negative pressure, such as thenegative pressure ball 1034 shown in fig. 2A, to provide intermittent NPWT. Thenegative pressure ball 1034 may have one-way valves 1032a, 1032b to ensure one-way negative pressure suction of the enclosed space. Anoptional relief valve 1030 may be incorporated into thewound interface 1015 or interposed between theport 1003 and thenegative pressure ball 1034 to limit the minimum negative pressure within the enclosed space. Theport 1003 may be sealingly opened or closed by a variety of principle means, including a self-sealing one-way valve 1032a that may be frequently used in medical applications. Thenegative pressure ball 1034 may be similarly equipped with a coupling port to connect to thevalve 1032a to provide intermittent negative pressure therapy, such as may be required in a remote military mission or rural health care setting.

In this embodiment, thebase flange 1004 is designed to be flexible, conformable, and capable of relieving diffusion pressure. This can be achieved individually or in various combinations including: thebase flange 1004 has a reduced thickness compared to the rest of thewound interface 1015, by molding or co-molding with a softer polymer, and/or by suitable structural modifications, to allow for increased flexibility and flexibility, either broadly or locally.

FIG. 2B illustrates one embodiment of this enhanced flexibility, wherein aliving hinge 1020 is provided along the perimeter of thebase flange 1004. Not shown, but will be understood by those of ordinary skill in the art upon studying this disclosure, is the incorporation of engineering of the blade diaphragm portion and the elasticity enhancement dispersed in the repeating sections or regions across thebase flange 1004. The result is better conformity to changing skin topography. While thebase flange 1004 may be secured directly to theskin 1011 by adhesive, one embodiment is to insert an optionalannular cushion 1005 between the base flange and the skin, thecushion 1005 may take the form of a closed cell foam 1012A (as shown on the left side of FIG. 2A) or anair bladder 1012b (as shown on the right side of FIG. 2A). In another exemplary variation for securing thewound interface 1015 to the skin, anannular skirt 1007 formed of a suitable bandage material, such as polyurethane, having anadhesive primer 1008 is adhered proximally to the base flange and distally to the skin to sealingly secure the wound interface to theskin 1011.

At times, a pad, such aspad 50, 150, 450, 550, 650, may optionally be configured for communication with the enclosed space to absorb exudate from the wound bed. Thecover 1002 forms a raised wound interface having a generally circular, rectangular, or oval space with thebase flange 1004 extending along the entire perimeter of thecover 1002.Wound interface 1015 is sealed toskin surface 1011 by means ofbase flange 1004, and an additional butoptional cushion 1005 orskirt 1007. As shown, thewound interface 1015 is fluid-tight in nature, with theenclosed space 1017 completely surrounding thewound bed 1013. The pressure p inside is set by introducing a fluid into theclosed space 1017 or by discharging a fluid from the closedspace 1017 through theport 1003₀. Pressure p₀Can be in the pressure range p_min≤p₀≤p_ambPeriodically changing to periodically expand thewound bed 1013 into theenclosed space 1017 and release the wound bed to the baseline state by reducing or releasing the negative pressure.

When the pressure p in the enclosed space₀Sufficiently below ambient pressure p_ambAt this point, thewound interface 1015 may have sufficient resistance to deformation to accommodate expansion of at least a portion of the wound bed into theenclosed space 1017. For example, in this embodiment, at pressure p₀＜p_ambIn use, thewound interface 1015 maintains theconcave surface 1025 of theenclosed space 1017 facing thewound bed 1013 to allow at least a portion of thewound bed 1013 to expand into theenclosed space 1017.

Fig. 3, 4A, 4B, 5A and 5B illustrate an exemplarywound treatment apparatus 10. As shown in fig. 3, the exemplarywound treatment apparatus 10 includes awound interface 15, thewound interface 15 including abase 20, acushion 30 and acover 40, thecushion 30 being secured around a perimeter circumference of the base 20 to enclose a perimeter of thebase 20, thecover 40 being hingedly connected to thebase 20. As shown, thebase 20, having an annular shape, defines anouter surface 21 and aninner surface 23 of thebase 20.

As shown, thebumper pad 30 is in the shape of a ring that corresponds in shape to the base 20 (see FIG. 5A), thebumper pad 30 defining anouter surface 31 and aninner surface 33. As shown, thedistal surface 32 of the cushion 30 (the surface of thecushion 30 facing the patient) is circumferentially and sealingly secured to theskin surface 11 via anadhesive layer 90, and theproximal surface 34 of the cushion 30 (the surface of thecushion 30 facing the physician) is sealingly secured to thedistal surface 22 of thebase 20 along the perimeter of thebase 20. In this embodiment, thecushion 30 cushions theskin surface 11 from thewound interface 15 and sealingly conforms to the contours of the skin surface. In this embodiment, theouter surface 21 is generally aligned with theouter surface 31 along the entire circumference of thebase 20 andcushion 30.

Thelid 40 is hingedly connected to thebase 20 by ahinge 45 that allows thelid 40 to be positioned between anopen position 46, shown in fig. 3, and aclosed position 48, shown in fig. 5A and 5B, to correspondingly unseal or engage thelid 40 from theproximal surface 24 of thebase 20. Thehinge 45 may be configured to releasably engage thecover 40 with the base 20 to allow thecover 40 to be replaced, such as a new cover, a non-transparent cover, or a cover with a different function, such as the cover 140 of the wound treatment apparatus 100 (see fig. 6, 7A, 7B).Hinge 45 may be, for example, a living hinge, a pinned hinge, a releasably engageable catch, or other hinge, as will be appreciated by one of ordinary skill in the art in view of this disclosure.

In some embodiments, thecover 40 can engage thebase 20 by other various mechanisms, such as threaded engagement, or frictional engagement, to allow thecover 40 to sealingly engage thebase 20, and to allow thecover 40 to disengage thebase 20. In some embodiments, thecover 40 may be removably or non-removably engaged with thebase 20. Various seals, compression fittings, and the like, may be provided on thecover 40, thebase 20, or both thecover 40 and the base 20 to sealingly engage thecover 40 with thebase 20. It should be noted that thehinge 45 is optional and may sometimes be omitted, for example the exemplarywound treatment apparatus 100 as illustrated in fig. 6, 7A and 7B, for example thehinge 45 may be omitted in the case where no direct intervention on thewound bed 13 is planned.

When the cover is in theopen position 46, it allows for a variety of direct interventions on the enclosedspace 17, such as the use of medical maggots to remove necrotic tissue, the placement of transplanted skin or other tissue on thewound bed 13. With thecover 40 in theclosed position 48, thedistal surface 32 of thecushion 30 is circumferentially and sealingly secured to theskin surface 11. in this embodiment, theenclosed space 17 may be defined by theinner surface 43 of thecover 40, theinner surface 23 of thebase 20, and theinner surface 33 of thecushion 30, and theenclosed space 17 is essentially fluid-tight when thewound interface 15 is secured to theskin surface 11.

Although the illustratedwound interface 15 is a cylindrical shape that encompasses a circular area of theskin surface 11, it should be understood that a wound interface, such as thewound interface 15, may, in some embodiments, assume other geometric shapes, such as rectangular, polygonal, or oval, to enclose wounds or areas of different shapes on theskin surface 11. For example, the wound interface may be oval and low profile to enclose a linear incision, such as from a caesarean section. The wound interface may be oval and have a higher profile to cover the breast after breast augmentation, or when reconstructing the breast after mastectomy. The term "annular" as used in this disclosure is meant to include other geometric shapes, such as polygonal, rectangular or oval shapes surrounding a chamber.

As shown,port 42 andsecond port 44 are disposed oncap 40 betweenouter surface 41 andinner surface 43 in fluid communication withenclosed space 17 such thatenclosed space 17 can be in fluid communication with sensors external toouter surface 41, e.g., a fluid reservoir, a fluid source, a fluid sink, a pump, a controller, a control module, e.g., control module 880 (see fig. 14), viaport 42 andsecond port 44, via tubing including hoses, tubing, valves, and other various fluid transports and fittings that can mate withport 42 andsecond port 44. Theport 42 and thesecond port 44 may be in fluid communication with: such as a compressed mechanical spring ball, a re-expandable enclosure driven by a variety of spring-like mechanisms, a mechanical or electrical pump, or a pump in combination with other elements, such as one or more sensors, valves, control modules, electronic circuitry, tubing, processors and software, to cooperate to provide fluid and therapy toenclosure 17 or to withdraw fluid fromenclosure 17. In this embodiment, theport 42 is located in a central location and thesecond port 44 is located at a periphery, but in other embodiments, theport 42 and thesecond port 44 may be located at different locations of thewound interface 15, may have mutually, or varying flow directions.Input fluid 78 may be input into enclosedspace 17 viaport 44,output fluid 76, which may contain exudate 18 (see fig. 5A and 5B), may be directed out ofenclosed space 17 via port 42 (see fig. 5A and 5B), or may flow in reverse with the fluid.

As shown in FIG. 3, stop means, such as stop means 49a, 49b, are circumferentially disposed about the periphery of thecover 40 in mechanical cooperation with corresponding base stop means 29a, 29b, the base stop means 29a, 29b being circumferentially disposed along therotatable locking ring 27 for releasably retaining thecover 40 in theclosed position 48 relative to the base 20 such that theenclosed space 17 is fluid tight. As shown, in this embodiment, a lockingring 27 is provided below theouter surface 21 of the base 20 to lock or release the cover by rotating or sliding in certain directions.

Various numbers of interengaging stops, such asstops 49a, 49b and base stops 29a, 29b, may be provided between the cover andbase 20, and their functional equivalents which may be provided in certain embodiments, may have a variety of shapes, sizes, operative configurations, etc., as will be appreciated by those of ordinary skill in the art in view of this disclosure. In certain embodiments, the fluid-tight seal between the cover and base is formed by employing face seals, radial seals, compression seals, with and without O-rings or gaskets, and other sealing means, as will be readily understood by those of ordinary skill in the art in view of this disclosure.

In this embodiment, thecushion 30 forms a cushion chamber 37 (see fig. 5A and 5B). Thecushion 30 may be formed of, for example, rubber or a polymer such as PVC or silicone. Anoptional cushion port 35 extends forward from theouter surface 31 of thecushion 30, through thecushion port 35, in fluid communication with thecushion chamber 37. The fluid, including air or other gas or liquid, within thecushion chamber 37 of thecushion 30 can be controllably adjusted through thecushion port 35 to provide a desired level of cushioning and sealing of thewound interface 15 relative to theskin surface 11. In other embodiments, cushion 30 may be formed from, for example, a variety of compressible, conformable, fluid-tight, closed-cell foams.

In certain embodiments, thebase 20 may be formed, for example, from one or more medical polymers including, for example, ABS, polystyrene, or polypropylene. Thecover 40 may be at least partially transparent to allow visual observation of the conditions within the enclosedspace 17, including thewound bed 13 and the portion of theenclosed skin surface 11 within the enclosedspace 17. Thecover 40 may be made of, for example, polycarbonate, acrylic, or other transparent polymeric material such as a copolyester, for example, Eastman Tritan available from Eastman Chemical Co^TM。

Fig. 3 illustrates apad 50 disposed within the enclosedspace 17 of thewound treatment apparatus 10. In this embodiment, thepad 50 is cylindrical, substantially annular, to leave a portion of the enclosedspace 17, in particular the space just above the wound bed, unoccupied by thepad 50, at least during some stage of treatment, such that thepad 50 does not make continuous contact with the wound bed. In this embodiment, theouter surface 51 of thecushion 50 can be biased toward at least a portion of theinner surface 33 of thecushioning pad 30, at least a portion of theinner surface 23 of thebase 20, or at least a portion of theinner surface 43 of thecover 40, wherein thecover 40 is in theclosed position 48. In certain embodiments, thepad 50 may be used during the initial exudation phase of wound therapy and removably placed within the enclosedspace 17 to allow periodic removal and replacement of thepad 50 while thecover 40 is in theopen position 46. In other embodiments, thepad 50 is securely affixed to thewound interface 15 within the enclosedspace 17, in which case the replacement of thepad 50 involves replacing thepad 50 and at least a portion of thewound interface 15, such as thepad 50 affixed to a removable andreplaceable cover 40.

Fig. 4A and 4B illustrate apad 50 of thewound treatment apparatus 10. In this embodiment, thecushion 50 is comprised ofcushion members 60, 70, 80, thecushion members 60, 70, 80 being die cut to the thickness of the material, such as with absorbent foam.Pad components 60, 70, 80 may be stacked upon one another or partially bonded together in a manner that does not impede fluid flow throughpad 50. As shown, when stacked on top of each other,distal surfaces 62, 72 are biased toward respectiveproximal surfaces 74, 84. In this embodiment,proximal surface 64 ofpad component 60 formsproximal surface 54 ofpad 50,distal surface 82 ofpad component 80 formsdistal surface 52 ofpad 50,inner surfaces 63, 73, 83 forminner surface 53 ofpad 50, andouter surfaces 61, 71, 81 formouter surface 51 ofpad 50 when stackable one on top of the other.

Pad 50 may include a different number of pad components, such aspad components 60, 70, 80, and the number of pad components (such aspad components 60, 70, 80) formingpad 50 may be selected to make up apad 50 of a desired thickness. An optional polymer wire may be disposed on themat 50 for removing themat 50 from the enclosedspace 17. Alternatively, thepad 50 may be formed as a unitary structure of preselected dimensions. In some embodiments,pad 50 absorbs exudate as a conduit for the passage ofexudate 18, out ofenclosed space 17 throughport 42, as shown in FIG. 5B. In certain embodiments, thepad components 60, 70, 80 may be formed of the same material or different materials in different spatial structural relationships, such as layers or columns, to form different fluid flow paths or wicking features, if desired. In some embodiments,pad assembly 60 may have at least one diagonal instead of beams, such asbeams 65, 67, orpad assembly 60 may have three or more beams instead of two beams in this embodiment. In some embodiments,pad component 60 may be formed as a continuous structure fromouter surface 51 toaxis 69, in which case the annular region withinpad component 60 would be omitted. Various embodiments of thepad 50 may include a single unitary molded or woven structure sized.

In the embodiment of fig. 4B, thepad components 70, 80 are annular in configuration.Pad assembly 60 is annular and includes at least one cross member, such ascross members 65, 67, emanating from aninner surface 63 ofpad assembly 60 and passing through anaxis 69 of the annulus, as shown. The cross-members 65, 67 intersect one another near theaxis 69 to form acentral portion 68, thecentral portion 68 being in fluid communication with theport 42, theport 42 being correspondingly positioned on thelid 40, theport 42 being in fluid communication with thecentral portion 68 of thecushion 50 when thelid 40 is in theclosed position 48.

Different designs of theabsorbent pad 50 may be possible for directing exudates away from the enclosedspace 17, in this embodiment, from the peripheral portion of thepad 50 toward thecentral portion 68 of thepad 50, thecentral portion 68 being in contact with theport 42.Exudate 18 may be transported frompad 50 tocentral portion 68 and then directed out ofpad 50 throughport 42. As shown in fig. 4A, theoutput fluid 76 and theinput fluid 78 may be in communication with theenclosed space 17 or woundbed 13 at least partially through theapertures 58 of thepad 50.

Fig. 5A and 5B further illustrate cross-sectional views of thewound treatment apparatus 10, taken along the axis 5-5 of fig. 3, where fig. 5A illustrates thewound treatment apparatus 10 in an exemplary first stage ofoperation 14 and fig. 5B illustrates thewound treatment apparatus 10 in an exemplary second stage ofoperation 16. As shown in fig. 5A and 5B, woundinterface 15 is sealingly secured toskin surface 11 to close woundboundary 12 such that a portion ofwound bed 13 onskin surface 11 is enclosed within fluid-tightenclosed space 17. At least a portion of thewound bed 13, such as the undercut, sinus and tunnel (see fig. 1), is located below theskin surface 11 and may be in fluid communication with theenclosed space 17. It should be noted that thewound boundary 12 may be enclosed within the enclosedspace 17, and the eroded area may extend below theskin surface 11 and beyond the enclosedspace 17.

As shown on the left side of fig. 5A, theadhesive layer 90 secures thedistal surface 32 of thebumper pad 30 to theskin surface 11, theadhesive layer 90 being interposed between thedistal surface 32 of thebumper pad 30 and theskin surface 11. As shown on the right side of fig. 5A,adhesive layer 90 may optionally extend beyond a portion ofskin surface 11 to encompass all of the skin surface in the area below and nearwound interface 15.Adhesive layer 90 is a member of the medically appropriate class of cyanoacrylates, such as N-butyl-2-cyanoacrylate (Histoacryl Blue) or octyl 2-cyanoacrylate (dermobond), and a water resistant coating covers the wound perimeter on the skin surface to protect normal skin from secondary maceration caused by prolonged exposure of the skin to fluids. Theadhesive layer 90 may be, for example, acrylic, silicone or hydrocolloid. In some embodiments, other securing mechanisms, such as straps with hook and loop fasteners, may also be used to secure, or at least partially secure, woundinterface 15 toskin surface 11.

In certain embodiments, the dressing may be omitted from thewound bed 13, which would allow direct assessment of the wound condition through the transparent portion of thecover 40 during a substantial portion of the wound treatment, since there is no contact of the dressing with thewound bed 13. In certain embodiments, thepad 50 may be in intermittent contact with thewound bed 13 during certain stages of operation. Even in such embodiments, at least a portion of the wound bed may be directly visible through the transparent portion of thecover 40 and the correspondingaperture 58 in thepad 50. Without continuous contact of the dressing with thewound bed 13, the painful problem of tearing of granulation tissue during dressing changes and the interruption of the healing process due to tearing can be avoided. Thewound interface 15 may only need to be replaced once a week, saving medical personnel time. Furthermore, since there is no dressing in the wound bed, thewound treatment apparatus 10 may be used from initial treatment until thewound bed 13 is fully healed, except that a dressing may be required during the initial exudation phase of thewound bed 13 on an intermittent basis. Thewound treatment device 10 may support a range of treatment methods such as proteolysis, debridement of drug maggots, antibiotic lavage and incubation of tissue matrix, skin grafting and stem cell culture, etc.

In afirst stage 14 of operation shown in fig. 5A, the pressure p within the enclosedspace 17 of thewound treatment apparatus 10₀≈p_amb. (Note that in some embodiments, the pressure p of thefirst stage 14 is operated₀＞p_amb). As shown in fig. 5A, thewound bed 13 and theskin surface 11 within the enclosedspace 17 are in abaseline state 93, thewound bed 13 being spaced from thedistal surface 62 of thepad assembly 60 of thepad 50 such that thewound bed 13 does not directly contact thepad 50, particularly thedistal surface 62 of thepad assembly 60. As shown in fig. 5A, woundinterface 15 forms anentrance 26 toenclosed space 17,as shown, and the portion of thewound bed 13 enclosed within thewound interface 15 may be entirely outside of theinlet 26 at the baseline condition 93 (e.g., not drawn up past theinlet 26 at the baseline condition 93). As shown, thecapillaries 96 adjacent thewound bed 13 are in a baselineunexpanded state 98, delivering substantial blood flow to thewound bed 13.

As shown in FIG. 5B, during thesecond phase 16 of operation of thewound treatment apparatus 10, due to the output of theoutput fluid 76, the pressure p within the enclosedspace 17₀＝p_min，p_min＜p_ambOutput fluid 76 may include air and other gases and liquids, as well asexudate 18 conducted fromenclosed space 17 throughport 42. As shown in fig. 5B, the pressure p in the closedspace 17₀＝p_minAt least a portion of thewound bed 13 is expanded and enters the enclosedspace 17 through theinlet 26 such that thewound bed 13 is in an expandedstate 94. In the dilatedstate 94, thewound bed 13 at theskin surface 11 and the portion of theskin surface 11 enclosed by the enclosedspace 17 are inflated, dilated and stretched, and thecapillaries 96, including capillaries, arterioles and venules proximate the wound bed, e.g., thecapillaries 96, can be in the dilatedstate 99. In the dilatedstate 99, the capillaries may be engorged and blood flow to thewound bed 13 may increase above baseline with corresponding beneficial benefits. In addition, swelling, which includes deformation and stretching of the tissue surrounding the Wound bed, has been found to stimulate fibrocyte differentiation and Wound healing (cf. Saxena, V.et. al., vacuum acquired trauma: Microdeformation of Wound and cell promotion. Amper. Soc. Plastic surg.1086-1096, 10 months 2004).

In the expandedstate 94, a portion of thewound bed 13, theskin surface 11, or both thewound bed 13 and theskin surface 11 may be biased toward at least a portion of thepad 50, such as a portion of thedistal surface 62 of thepad member 60, as shown in fig. 5B. In the expandedstate 94, a portion of thewound bed 13, theskin surface 11, or portions of thewound bed 13 and theskin surface 11 may be biased toward theinner surface 53 of thepad 50. Pressure p_minThe expandedstate 94 may be selected to produce a biased connection of thepad 50 to at least a portion of thewound bed 13. By passingThe biased connection between thepad 50 and thewound bed 13, thepad 50 absorbsexudate 18 from the wound bed 13 (as indicated by the solid black arrows in fig. 5B). Thepad member 80 of thepad 50, which surrounds thewound bed 13, contacts theskin surface 11, as shown, and may absorbexudate 18 from the periwound area within the enclosedspace 17. Thus,exudate 18 may be absorbed by at least a portion ofpad 50 in different directions acrosswound interface 15 and then drawn throughport 42 and out ofpad 50.

After thepad 50 absorbs theexudate 18, theexudate 18 may pass through thepad 50 to thecentral portion 68 through a combination of capillary action and a suction gradient, and theexudate 18 may then be conducted out of thepad 50 at thecentral portion 68 through theport 42 connected to thecentral portion 68, thereby conducting theexudate 18 out of the enclosedspace 17. When negative pressure is released by the input ofinput fluid 78 throughsecond port 44,input fluid 78 into the enclosed space, particularly when it is a sudden input, may provide a pushing force to pushexudate 18 frommat 50 forward into a tube connected to port 42, into a container, such as container 881 (see fig. 14), to evacuate the conduit. It should be noted that theoutput fluid 76 from the enclosedspace 17 may comprise a gaseous fluid or other fluid associated withexudate 18 withinenclosed space 17 to reduce the pressure p withinenclosed space 17₀。

By periodically varying the pressure p in the enclosedspace 17₀Substantially in the pressure range p_min≤p₀≤p_ambb, thewound treatment apparatus 10 may be periodically changed between a first stage ofoperation 14 and a second stage ofoperation 16, where p_minIs the minimum pressure at which the pressure varies periodically. Pressure p₀Can be altered by introducing theinput fluid 78 into the enclosedspace 17 and removing theoutput fluid 76 from the enclosedspace 17, a control module, such as acontrol module 880 of the wound treatment apparatus 800 (see fig. 14), can be operatively connected to thewound interface 15 to introduce theinput fluid 78 into the enclosedspace 17 and to remove theoutput fluid 76 from the enclosedspace 17. The minimum pressure may be, for example, p_min≈p_amb-150mm Hg.. The minimum pressure may be, for example, p_min≈p_amb-70mm Hg. The minimum pressure may be, for example, generally within the pressure range (p)_amb-130mm Hg)≤p_min＜(p_amb-80mm Hg). Minimum pressure p_minCan be generally in the pressure range (p)_amb-90mm Hg)≤p_min＜p_ambAnd (4) the following steps.

In certain embodiments, the pressure p₀Is usually located in a pressure range p_min≤p₀≤p_maxIn which p is_max＞p_amb. For example, p_max≈(p_amb+30mm Hg). In certain embodiments, p_max≈p_amb. In some embodiments, p_max＜p_ambE.g. maximum pressure p_maxMay be at ambient pressure p_ambAnd less from about-5 mm Hg to about-20 mm Hg.

The pressure p is varied as thewound treatment apparatus 10 changes from the first stage ofoperation 14 to the second stage ofoperation 16₀Reduction of p₀→p_minIn the expandedstate 94 in the second stage ofoperation 16, thewound bed 13 is expanded through theinlet 26 into the enclosedspace 17 to assume the expandedlength 19. As thewound treatment apparatus 10 changes from the second stage ofoperation 16 to the first stage ofoperation 14, with the pressure p₀Increase p of₀→p_maxThewound bed 13 is released from the tensioned state to thebaseline state 93. In thefirst stage 14 of operation, thewound bed 13 is in abaseline state 93 with essentially no expanded length, such as expandedlength 19. Thus, between the expandedstate 94 and thebaseline state 93, at least a portion of thewound bed 13 expands into the enclosedspace 17 and releases from expanding into the enclosedspace 17, respectively, periodically corresponding to the pressure p₀In the pressure range p_min≤p₀≤p_maxPeriodically changing. Normal pressure p₀In the pressure range p_min≤p₀≤p_maxPeriodically varying, the wound bed, including surrounding tissue, may be massaged to induce a corresponding fresh blood flow, periodically flushing the wound bed to provide, for example, nutrients, immune factors, and oxygen.

Further, in this embodiment, the pressure p₀The periodic variation of (a) results in a transient and intermittent contact between thepad 50 and thewound bed 13 such that granulation tissue of thewound bed 13 will not grow into thepad 50 at times, in other words will not tear or damage the granulation tissue when thepad 50 or the wound interface containing thepad 50 is replaced. At a particular moment during the pressure change, the pressure p₀May be substantially constant throughout theenclosed space 17 such that theentire wound bed 13 is exposed to the pressure p₀Thus, no significant pressure gradient is created around thewound bed 13, which may result, for example, in a reduction of blood flow near thewound boundary 12. It should be noted that asexudate 18 is absorbed,pad 50 may become swollen, thus allowingpad 50 to maintain a varying degree of contact withwound bed 13, despite pressure p₀In the pressure range p_min≤p₀≤p_maxPeriodically changing, the wound bed is inflated to increase contact between thewound bed 13 and thepad 50, or thewound bed 13 is retracted to decrease contact between thewound bed 13 and thepad 50, but thepad 50 remains in contact with thewound bed 13 at all times.

Aninput fluid 78 formed by a gas or gas mixture can be introduced into the closedspace 17 via thesecond port 44 to at least partially regulate the pressure p in the closedspace 17₀Or to control the composition of the gaseous fluid within the enclosedspace 17. For example, by introducing theinput fluid 78 into the enclosedspace 17 through thesecond port 44 and theoutput fluid 76 out of the enclosedspace 17 through theport 42, thewound treatment apparatus 10 may be periodically changed between the first stage ofoperation 14 and the second stage ofoperation 16. The introduction ofinput fluid 78 into enclosedspace 17 throughsecond port 44 and the removal ofoutput fluid 76 fromenclosed space 17 throughport 42, or vice versa, may enhance the removal ofexudate 18 fromenclosed space 17 and may increase the fluid velocity in the conduit by increasing the flow rate, thereby preventing clogging. In certain embodiments, oxygen supplementation is particularly important for rescuing hypoxic tissue at the margin of death, as well as for supporting cellular functions, such as cell division and collagen synthesis, withinfusionFluid 78 may include a gas having an oxygen concentration greater than atmospheric air. The added oxygen can inhibit the growth of anaerobic bacteria. Theinput fluid 78 may be a liquid, such as saline, to irrigate wounds, enclosed spaces and drains, or other therapeutic fluids, including antibiotic irrigation, or amniotic fluid for stimulating regenerative effects.

Fig. 6, 7A, and 7B illustrate another exemplary embodiment of awound treatment apparatus 100. As shown in fig. 6, in this embodiment, woundinterface 115 ofwound treatment apparatus 100 includesbase 120 andapron 180. The underside ofskirt 180 is coated with adhesive 190,skirt 180 being annular in shape and disposed about the entire periphery ofbase 120,base 120 occupying a portion of the annular region defined byskirt 180. In this embodiment, the distal periphery ofskirt 180 is sealingly secured toskin surface 111 by adhesive 190.Apron 180 may be sized to provide sufficient adhesive force to maintainwound interface 115 attached toskin surface 111.Apron 180 may be formed of a bandage material such as polyurethane. As shown in fig. 6, woundinterface 115 includes aport 142 at the wound interface that forms alumen 143 for fluid communication withenclosed space 117. Via thelumen 143 of theport 142, as indicated by the arrows in fig. 6, theinput fluid 178 may be introduced, or theoutput fluid 176 may be directed out of theenclosed space 117.

As shown in fig. 7A, woundinterface 115 ofwound treatment apparatus 100 includes acushion 130 secured to flange 129 ofbase 120 and anapron 180. In this embodiment, woundinterface 115 is resistant to deformation. In this embodiment, theflange 129 is sealingly secured around the entire perimeter of thebase 120, which can spread pressure and conform to theskin surface 111. Theflange 129, which may be made of a medical grade polymer such as polyethylene terephthalate (PET), Polytetrafluoroethylene (PTFE), polypropylene (PP), Polyurethane (PU) and silicone, for example, may be sealingly secured to theskin surface 111 by an adhesive.Cushion 130 is optional and may assist in spreading localized pressure or in providing a fluid-tight seal betweenwound interface 115 and skin surface 11 l. As shown in fig. 7A, thebumper pad 130 has a ring shape, and thebumper pad 130 is fixed around the entire circumference of thebase 120. As shown, theproximal side 134 of thebumper pad 130 is sealingly secured to thedistal side 131 of theflange 129 along the entire perimeter of thebase 120. As shown in fig. 7A, thedistal side 132 of thecushion 130 is biased toward theskin surface 111 around thewound bed 113 to cushion the force of the wound treatment device against theskin surface 111 or to conform to the contour of theskin surface 111. In this embodiment, thecushion 130 forms acushion chamber 137. In some embodiments, cushion 130 can be omitted, in whichcase base 120 can be held biased toward attachment toskin surface 111 byskirt 180, or bydistal side 131 offlange 129, or by the cooperation ofskirt 180 anddistal side 131 offlange 129 withadhesive layer 190. In embodiments wherecushion 130 is omitted,base 120 can be supported byskirt 180 in a spaced relationship withskin surface 111.

As shown,skirt 180 is sealingly secured toproximal side 133 offlange 129,skirt 180 being sealingly secured toskin surface 111 along the entire perimeter ofbase 120 byadhesive layer 190 such that woundboundary 112 is covered by fluid-tight enclosure 117.

As shown in fig. 7A, a portion of thebase 120 is bifurcated to form avoid 127, and thepad 150 is received in at least a portion of thevoid 127. In this embodiment, channels, such aschannels 128a, 128b, 128c, are formed in at least a portion of thedistal end 122 of the base 120 to allow fluid communication between theenclosed space 117 and the void 127 containing thepad 150, thepad 150 being received within thevoid 127.Exudate 118 emanating fromwound bed 113 may pass through channels, such aschannels 128a, 128b, 128c, intovoid 127 for absorption bypad 150. As shown,port 142 is in fluid communication withvoid 127 containingpad 150 throughlumen 143 to directoutput fluid 176 containingexudate 118 frompad 150. When enclosedspace 117 is in fluid communication withport 142 through a passage, such aspassages 128a, 128b, 128c,output fluid 176 may be directed out ofenclosed space 117 throughlumen 143 ofport 142. A variety of numbers of channels, such aschannels 128a, 128b, 128c, may be provided in different applications. Theport 142, as well as any additional ports, may be configured for connection to a conduit, via theport 142, through the conduit, for fluid communication with theenclosed space 117. A control module, such ascontrol module 880 of wound treatment apparatus 800 (see fig. 14), may be operatively connected to lumen 143 ofport 142 to directinput fluid 178 intovoid 127 andenclosed space 117 throughlumen 143 or to directoutput fluid 176 containingexudate 118 fromenclosed space 117 and void 127 throughlumen 143.

In this embodiment,base 120 includes one or more windows made of a transparent material, such aswindows 139a, 139b, 139c, 139d, to allow visual inspection ofwound bed 113 throughbase 120 andpad 150. As shown, thewindows 139a, 139b, 139c, 139d pass between theproximal side 124 and thedistal side 122 of thechassis 120, including passing through a portion of thegap 127.

In thefirst stage 114 of exemplary operation, as shown in FIG. 7A, the pressure p within theenclosed space 117₀≈p_amb. Thewound bed 113 is in thebaseline state 193, and thewound bed 113 is in a spatial relationship with a portion of thedistal side 122 of thechassis 120, including the channels, such as thechannels 128a, 128b, 128c, such that thewound bed 113 does not directly contact the channels orpads 150. As shown in fig. 7A, thewound interface 115 forms anentrance 126 into theenclosed space 117, and in thebaseline state 193, the portion of thewound bed 113 enclosed by theenclosed space 117 may be outside of theentrance 126.

As shown in FIG. 7B, in asecond stage 116 of exemplary operation of thewound treatment apparatus 100,output fluid 176 is directed from theenclosed space 117 through thelumen 143 of theport 142, and theenclosed space 117 is evacuated to a degree such that a pressure p within theenclosed space 117 is generated₀Less than ambient pressure p_amb(i.e. p)₀＜p_amb) This causes at least a portion of thewound bed 113 to expand into theenclosed space 117 through theinlet 126 in the expanded state, with at least a portion of thewound bed 113 biased toward thedistal side 122 of thechassis 120, including channels, such aschannels 128a, 128b, 128 c. During the second stage ofoperation 116,exudate 118 may be conducted therefrom out ofwound bed 113 intovoid 127 through channels, such aschannels 128a, 128b, 128c, for absorption bypad 150.Pad 150 is in fluid communication withlumen 143 ofport 142, thus permittingpermeationThe effluent 118, as at least a portion of theoutput fluid 176, may be directed out of thepad 150 through theport 142 via external suction applied to theport 142.

By total pressure in the pressure range p_min≤p₀≤p_maxPeriodically varying the pressure p in theenclosed space 117₀Thewound treatment apparatus 100 may be periodically changed between thefirst stage 114 of operation and thesecond stage 116 of operation to correspondingly expand thewound bed 113 into the enclosed space in the expandedstate 194 and relax thewound bed 113 from expanding into theenclosed space 117 back to thebaseline state 193 to massage thewound bed 113. In this embodiment, p is usually_min＜p_ambAnd p_amb≤p_max. At a specific time during the pressure change, the pressure p₀Is substantially constant throughout theenclosed space 117 such that theentire wound bed 113 is exposed to the pressure p₀This, for example, may result in an increase in blood flow near the wound boundary. Periodically disconnecting thewound bed 113 from contact with thedistal side 122 of the base 120 may prevent thewound bed 113 from adhering to thedistal side 122 of thebase 120, channels, such aschannels 128a, 128b, 128c, or thepad 150. When pressure p is₀＝p_minAt this point, woundinterface 115 may have sufficient resistance to deformation to maintain the fluid-tightness ofenclosed space 117, thereby allowing woundbed 113 to expand intoenclosed space 117 and be released from expansion back tobaseline state 193. When pressure p is₀＝p_minAt this time, thewound interface 115 may have sufficient resistance to deformation to maintain theinlet 126 to theenclosed space 117, thereby allowing thewound bed 113 to expand into theenclosed space 117 and be released from expansion back to thebaseline state 193.

As shown in fig. 7A, when thewound bed 113 is in thebaseline state 193, thecapillaries 196 adjacent thewound bed 113 are in the baselineunexpanded state 198, and a baseline amount of blood is delivered to thewound bed 113 in thefirst stage 114 of operation. As shown in fig. 7B, when in the second stage ofoperation 116, thewound bed 113 is in an expandedstate 194, capillaries proximate the wound bed, such ascapillaries 196, may be in an expandedstate 199.

Through theport 142, theinput fluid 178 may be input into theenclosed space 117, as indicated by the arrow in FIG. 6, for example, to at least partially regulate the pressure p within theenclosed space 117₀To control the composition of the gaseous fluid within theenclosed space 117, or for other therapeutic purposes. For example, thewound treatment apparatus 100 may be periodically changed between the first stage ofoperation 114 and the second stage ofoperation 116 by continuously inputting theinput fluid 178 into theenclosed space 117 and exporting theoutput fluid 176 from theenclosed space 117 through theport 142.

Fig. 8 illustrates an exemplarywound treatment apparatus 200. As shown in fig. 8, woundtreatment apparatus 200 includes a deformation-resistant wound interface 215, woundinterface 215 forming anenclosed space 217,enclosed space 217 being fluid-tight whenwound interface 215 is coupled toskin surface 211 to enclose woundbed 213 onskin surface 211. As shown in fig. 8, woundinterface 215 includes acover 240, cover 240 being slidably, sealingly, frictionally, removably connected tobase 220. Thecover 240 may include at least a portion that is transparent to allow visual inspection of thewound bed 213 through thecover 240. As shown, thebase 220 may include aflange 209 along an outer periphery of the base 220 that may be used to provide a structural support or sealing surface when mated with thecover 240. In other embodiments, thecover 240 and the base 220 may form a unitary structure.

As shown in fig. 8, thebase 220 may include aflange 229 generally along the periphery of theouter side 223 at thedistal end 222 of thebase 220, theflange 229 being secured to theskin surface 211 by an adhesive 290. As shown in fig. 8,flange 229 may be designed to be flexible and conformable toskin surface 211 by its thickness and/or polymeric material to enable sealingwound interface 215 to wound 213 in a fluid-tight manner while distributing the forces ofwound interface 215 from pressure p withinenclosed space 217 toskin surface 211₀. Is in fluid communication with theenclosed space 217 through thelumen 243 of theport 242 located on thewound interface 215. Mats, such asmats 50, 150, 450, 550, 650, 750 (see fig. 10, 11A, 11B, 12, and 13A), may be deployed in enclosed spaces217, the pad may be in fluid communication with theinner lumen 243 of theport 242 to allow exudate from thewound bed 213 to be transferred out through the pad and theinner lumen 243 of theport 242. One or more additional ports, such asport 244, in fluid communication with theenclosed space 217, located on thewound interface 215, may be used to monitor internal space parameters within theenclosed space 217, may be used for communication with fluid within theenclosed space 217, or may be used for intervention of other therapies within theenclosed space 217. When not in use,port 244 may be closed by avalve 299, including, but not limited to, for example, a plug, a clip, various switches, and a solenoid valve.

Fig. 9 illustrates an exemplarywound treatment apparatus 300. As shown in fig. 9, woundtherapy apparatus 300 includes awound interface 315, woundinterface 315 comprising abase 320 and acover 340.Base 320 is formed to includeflange 329 andreceptacle 310.Flange 329 is an annular structure extending outwardly fromouter side 323 atdistal end 322 ofbase 320.Flange 329 may be a unitary part ofbase 320. As shown in fig. 9,flange 329 may be adhered toskin 311 at the periphery ofwound bed 313 by adhesive 390. Thecover 340 may be inserted into a hole formed in thecontainer 310, and as shown in fig. 9, thecontainer 310 may have a groove for easy insertion. In this embodiment, stop 309, formed by an inward flange, limits the insertion oflid 340 intocontainer 310, providing an additional sealing surface between the lid and base to form a fluid-tight seal betweenlid 340 andbase 320 so thatenclosed space 317 is sealed. A pad, such aspad 50, 150, 450, 550, 650, 750, may optionally be disposed withinenclosed space 317 in fluid communication withlumen 343 ofport 342.

Fig. 10 illustrates a portion of an exemplarywound treatment apparatus 400. As shown in FIG. 10, thewound interface 415 includes acover 440, thecover 440 forming, or partially forming, anenclosed space 417 enclosing awound bed 413 on askin surface 411, apad 450 attached to aninner surface 446 of thecover 440 in communication with an interior 443 of theport 442 when a pressure p within theenclosed space 417₀When reduced, thewound bed 413 is caused to expand into contact with thepad 450, thepad 450 being connected to at least a portion of thewound bed 413. As thewound bed 413 is in contact with thepad 450, exudate may be transferred from thewound bed 413 to the pad450, out ofenclosed space 417 vialumen 443 ofport 442. Thelumen 443 passes between theinner surface 446 and theouter surface 448 of thecap 440 as shown.

In this embodiment, thepad 450 has a generally cylindrical configuration of unitary construction, with thepad 450 extending outwardly from thedistal side 446 of thecover 440 into contact with thewound bed 413 during at least a portion of the periodic pressure change. The length X of thepad 450 may be less than the length Y from thedistal side 446 of thecover 440 to theskin surface 411 or to thewound bed 413. Although thepad 450, if soft and compressible, may be configured to always contact the wound bed 450(X ═ Y), one consequence of X < Y is that only the pressure p within theenclosed space 417 is₀Sufficiently lower than p_ambTo allow thewound bed 413 to expand into contact with thepad 450, thepad 450 is in contact with thewound bed 413. During such intermittent contact, exudate may be conducted from the wound bed to thepad 450, through theport 442, and in turn from theenclosed space 417.

Fig. 11A and 11B illustratestages 505, 510, respectively, of an exemplary operation of an exemplarywound treatment apparatus 500. As shown, the exemplarywound treatment apparatus 500 includes awound interface 515 having aninner surface 543 and anouter surface 546, theinner surface 543 forming anenclosed space 517. As shown, thepad 550 is disposed within theenclosed space 517, and theport 542 defines aninternal cavity 549 between aninner end 545 and anouter end 547 of theport 542. Aninner lumen 549 passes through theinner surface 543 and theouter surface 546 of the wound interface for fluid communication with theenclosed space 517.

As shown in FIG. 11A, in a first phase ofoperation 505, the pressure p within the enclosed space₀Is less than p_amb.Output fluid 563 in gaseous form passes fromenclosed space 517 throughpad 550, then throughinner chamber 549, and outinner end 545 toouter end 547, as shown by the solid arrows in fig. 11A. As shown, the resulting pressure gradient biases the portion ofsurface 551 ofpad 550 toward theinner end 545 ofport 542.Exudate 561, as shown by the dashed arrows in fig. 11A, passes throughpad 550 and then throughinterior chamber 549, exiting frominterior end 545 toexterior end 547. It is noted that in certain embodiments,output fluid 563 may comprise a liquid, a gas, or a combination of gas and liquid.

In asecond stage 510 of operation, shown in FIG. 11B, the pressure p in the enclosed space₀Is greater than or equal to p_ambSurface 551 ofpad 550 disengages frominner end 545 ofport 542. Thus, in this exemplary application of thewound treatment apparatus 500, in the first phase ofoperation 505, when fluid is being directed fromenclosed space 517 throughport 542,surface 551 ofpad 550 is biased towardinner end 545 connectingport 542, and in the second phase ofoperation 510, when no fluid is being directed fromenclosed space 517 throughport 542, or fluid is being input,surface 551 ofpad 550 is out of contact withinner end 545 ofport 542. As shown in fig. 11A, aspiration ofoutput fluid 563 throughport 542 pullspad 550 towardinner end 545 ofconnection port 542, and then allowsexudate 561 to be directed out ofpad 550 throughport 542. When the attractive force exerted atport 542 ceases, as shown in fig. 11B,pad 550 is released from contact with theinner end 545 ofport 542.

As shown in fig. 12, the example woundtreatment device 600 includes awound interface 615 having aninner surface 643 and anouter surface 646, theinner surface 643 forming anenclosed space 617. Thepad 650 is disposed within theenclosed space 617, and as shown, theport 642 forms alumen 649 between aninner end 645 and anouter end 647 of theport 642. Thelumen 649 passes through theinner surface 643 and theouter surface 646 of the wound interface. As shown in fig. 12, the pressure p in the enclosed space₀Is approximately equal to p_ambNo attractive force is applied toport 642 to remove fluid fromenclosed space 617. In contrast to the exemplarywound treatment apparatus 500 illustrated in fig. 11A and 11B, thesurface 651 of thepad 650 remains biased toward theinner end 645 of theport 642, as shown in fig. 12. Thus, in this embodiment,surface 651 is biased into contact with theinner end 645 ofport 642 during the period of time that fluid is being conducted out ofenclosed space 617, or during the period of time that fluid is ceasing to be exhausted fromenclosed space 617 throughport 642, or even during the period of time that fluid is being input into the enclosed space throughport 642.

Fig. 13A and 13B illustrate an exemplarywound treatment apparatus 700. As shown in fig. 13A, woundinterface 715 ofwound treatment apparatus 700 defines anenclosed space 717, andpad 750 is disposed withinenclosed space 717 in fluid communication withlumen 743 ofport 742. As shown in fig. 13A, 13B, thepad 750 is formed of a woven composite of synthetic fibers and may includehydrophobic fibers 792,hydrophilic fibers 790 andelastic fibers 794.

Various braided structures may be configured to holdfibers 790, 792, and 794 together. In one embodiment, a simple wool knit is used to form a two-layer structure, one layer being primarilyhydrophilic fibers 790 and the other layer being primarilyhydrophobic fibers 792. The structure can then be folded upon itself and sewn at the open perimeter to form apad 750, with thesurface 751 adjacent thepad 750 being primarilyhydrophobic fibers 792 and the interior 753 disposed within thepad 750 being primarilyhydrophilic fibers 790, as shown in fig. 13B. Thehydrophobic fibers 792 force exudates, including other liquids from thesurface 751 to flow onto thehydrophilic fibers 790 within theinterior 753. Exudate may be retained by thehydrophilic fibers 790 and may be transferred through thehydrophilic fibers 790 to thelumen 743 ofport 742, by the negative pressure applied to thelumen 743, and out of theenclosure 717.

In fig. 13A, thepad 750 takes the form of an inverted bowl positioned above thewound bed 713. Thepad 750 may not directly contact the wound bed except during a certain phase of operation of thewound treatment apparatus 700 when the pressure p within theenclosed space 717₀When the negative pressure is sufficient, the wound bed is pulled into contact with thepad 750. When woundbed 713 is in contact withpad 750, exudate fromwound bed 713 may transfer fromwound bed 713 intopad 750, throughpad 750, frompad 750 toport 742.Pad 750 can haveoptional regions 796,regions 796 being in at least intermittent contact withport 742, with no or very fewhydrophobic fibers 792 atregions 796 ofsurface 751. Thepad 750 may additionally have different weave structures in different areas of thepad 750 for specific applications. For example, at a portion of thesurface 751, thefibers 792 are primarily hydrophobic in order to reduce the humidity at thesurface 751 and, thus, reduce the likelihood of skin maceration due to prolonged wet contact with that portion of thesurface 751. In certain embodiments, thepad 750 may be alternatively and removably deployed within thewound interface 715, or thepad 750 may be fixedly joined with thewound interface 715.

Fig. 14 illustrates an exemplarywound treatment apparatus 800. As shown in fig. 14, thewound treatment apparatus 800 includes agas source 882 and aliquid source 884 in fluid communication with acontrol module 880, thecontrol module 880 being in fluid communication with thewound interface 815. As shown, awound interface 815 is secured to theskin surface 811, forming anenclosed space 817 above a wound bed (e.g., woundbeds 13, 113, 213, 313, 413, 713, 1013).Wound interface 815, may be similar to, for example, woundinterface 15, 115, 215, 315, 415, 515, 615, 715, 1015, enclosedspace 817 may be correspondingly similar toenclosed space 17, 117, 217, 317, 417, 517, 617, 717, 1017. Thecontrol module 880 may monitor various parameters within theenclosed space 817, such as the pressure p₀Control module 880 may interact with these parameters to provide different treatment methods.

In this embodiment, thecontrol module 880 includes acontrol group 893 and areceptacle 881, thecontrol group 893 including amicrocontroller 887, themicrocontroller 887 being in operable communication with thepower source 898, a user I/O (input/output) 886, avalve 888, apump 889 and apressure sensor 891 to control or monitor operation of thepower source 898, thevalve 888, thepump 889 and thepressure sensor 891, at least in part in response to user input entered via the user I/O886.Microcontroller 887 may include, for example, a microprocessor, memory, analog/digital converters, digital/analog converters, clocks, I/O connectors, and the like, andmicrocontroller 887 may be configured, for example, as a single chip or chip set mounted on a board, as will be readily appreciated by those of ordinary skill in the art after studying this disclosure.

Thepower supply 898 may be, for example, a mains supply or a battery, and thepower supply 898 may include, for example, a transformer, an inverter, a rectifier, or a voltage filter. In this illustration, thevalve 888 and thepressure sensor 891 can accordingly represent a different number and configuration of valves and a different number and configuration of pressure sensors. Various communication paths may be arranged aroundcontrol module 880 to transmit power frompower supply 898 tomicrocontroller 887,valve 888, pump 889, andpressure sensor 891.

The user I/O886 may include a variety of switches, buttons, dials, etc., whether virtual or physical, for obtaining user input, which is then communicated to themicrocontroller 887 to allow the user to direct the operation of thewound treatment apparatus 800. Various communication paths such as electrical, electromagnetic (such as bluetooth), optical (such as laser, infrared radiation) and networking communications may be employed for communication betweenmicrocontroller 887 and user I/O886. Themicrocontroller 887 controls the operation of thewound treatment apparatus 800 including acontrol module 880, which communicates to themicrocontroller 887, at least in part, based on user input from the user I/O886. Themicrocontroller 887 may communicate reference data for the operation of thewound treatment apparatus 800 to the user I/O886, which the user I/O886 may display to the user. In some embodiments, user I/O886 may be located nearmicrocontroller 887, and user I/O886 may be, at least in part, remote frommicrocontroller 887, in network communication withmicrocontroller 887.

As shown in FIG. 14, agas source 882 fluidly communicatesgas 883 with thecontrol group 893 of thecontrol modules 880 and aliquid source 884 fluidly communicates liquid 885 with thecontrol group 893 of thecontrol modules 880. Thecontrol group 893 of thecontrol module 880 is controlled by themicrocontroller 887 and is operable to select whether theinput fluid 846 isgas 883 from thegas source 882, or liquid 885 from theliquid source 884, or a combination ofgas 883 from thegas source 882 and liquid 885 from theliquid source 884. Aninput fluid 846, controlled by acontrol group 893 of thecontrol module 880, is directed into theenclosed space 817. Theinput fluid 886 may, for example, be equivalent to theinput fluids 78, 178.

In this embodiment, acontrol group 893 of the control module 840, controlled by themicrocontroller 887, can use thevalve 888, thepump 889, and thepressure sensor 891, operatively to control the flow of theinput fluid 846 from thecontrol module 880 to theenclosed space 817 of thewound interface 815, or to control the flow of theoutput fluid 848 from theenclosed space 817 of thewound interface 815 to thecontrol module 880, or to control the discharge of at least a portion of theoutput fluid 848 into the ambient environment.Output fluid 848 may be, for example, identical tooutput fluids 76, 176, 563.

Control module 880 can controlinput fluid 846 to flow intoenclosed space 817 andoutput fluid 848 to flow out of enclosed space 817To circulate the pressure p in theenclosed space 817₀E.g. in the pressure range p_min≤p₀≤p_max. Thevalve 888 may include one or more valves disposed on thecontrol module 880 and operable, for example, to select theinput fluid 846 from thegas 883 of thegas source 882 or the liquid 885 of theliquid source 884 to control the flow of theinput fluid 846 from thecontrol module 880 to theenclosed space 817 of thewound interface 815 and to control theoutput fluid 848 to be directed out of theenclosed space 817 of thewound interface 815 into thecontrol module 880. Thepressure sensor 891 may include at least one or more pressure sensors operable, for example, to monitor thegas 883, liquid 885,input fluid 846,output fluid 848, or pressure p at various locations within theenclosed space 817 of thewound interface 815₀The pressure of (a). Themicrocontroller 887 can alter the operation of thevalve 888 or thepump 889 in response to a signal from thepressure sensor 891. Theinput fluid 846 may be circulated under pressure from thegas source 882 orliquid source 884, and thepump 889 may be used to deliver theoutput fluid 848 from theenclosed volume 817 to thereservoir 881 to prevent entry into the surrounding environment.

Thewound treatment apparatus 800 may include a variety of fluid delivery devices, such as hoses, lines, valves, conduits, connectors, pressure regulators, and a variety of other fittings to communicategas 883 and liquid 885 fromgas source 882 andliquid source 884, respectively, to thecontrol module 880 for communicatinginput fluid 846 andoutput fluid 848 between theenclosed space 817 of thewound interface 815 and thecontrol module 880.

After theoutput fluid 848 is directed out of theenclosed volume 817 of thewound interface 815,exudate 819 or liquid, such asliquid 885, from theoutput fluid 848 flows through thereservoir 881 when returning to thecontrol module 880, is captured from theoutput fluid 848 in thecavity 899 of thereservoir 881. As shown, the gaseous portion ofoutput fluid 848, or gases vented fromcavity 899 ofcontainer 881 by capturing exudates or liquids withincavity 899, may then be exhausted fromcontrol module 880 to the ambient environment

In operation, a wound treatment apparatus, such aswound treatment apparatus 10, 100, 200, 300, 400, 500, 600, 700, 800, 1000, is usedWound beds in the treatment enclosure, such aswound beds 113, 113, 213, 313, 413, 7131013, for exampleenclosed spaces 17, 117, 217, 317, 417, 517, 617, 717, 817, 1017, are fluid-tight and enclose the wound bed on the skin surface. A wound interface, such aswound interface 15, 115, 215, 315, 415, 515, 615, 715, 815, 1015 of a wound treatment apparatus is secured to a skin surface, such asskin surface 11, 111, 211, 311, 411, 711, 811, 1011, surrounding a wound bed such that at least a portion of the wound bed proximate the skin surface is located within the enclosed space. A variety of adhesives may be applied to the skin surface around the wound bed to protect the skin surface or to secure portions of the wound treatment device to the skin surface. After fixation to the skin surface surrounding the wound bed, fluid may be expelled from the enclosed space through a port in fluid communication with the enclosed space, e.g.,port 42, 142, 242, 342, 442, 542, 642, 742, 1003, and fluid may be input into the enclosed space through a port in fluid communication with the enclosed space or through a second port, e.g.,port 44, 144, 244, to periodically vary the pressure p within the enclosed space₀In the pressure range p_min≤p₀≤p_maxVariations, in certain embodiments, p_maxMay be greater than ambient pressure p_ambMaximum pressure p_maxMay be approximately equal to ambient pressure p_ambOr maximum pressure p_maxMay be less than ambient pressure p_amb. Pressure range p during wound therapy_min≤p₀≤p_maxMay be changed.

Periodically changing pressure p in an enclosed space₀The wound bed may be alternately expanded into the enclosed space and released from the expanded state back to the baseline state to massage the wound bed and surrounding tissue, and the vascular system adjacent to the wound bed may be massaged, thereby increasing blood flow to the wound bed. The resulting surge of blood flow near the wound bed may promote healing of the wound bed. Massaging the wound bed may facilitate the distribution and drainage of exudate from the wound bed. It should be noted that when p is₀Becomes smaller than p_ambThe wound bed is expanded intoThe enclosed space will not normally start immediately, but with pressure p₀Becomes sufficiently smaller than p_ambIt is started.

A control module, such ascontrol module 880, may control the entry and exit of input fluid into and out of the enclosed space, which may include a liquid, a gas, or a mixture of liquid and gas. A variety of liquids, gases, and combinations of liquids and gases may be introduced into the enclosed space, and the liquids, gases, and mixtures of liquids and gases may be varied during wound treatment.

A pad, such aspad 50, 150, 450, 550, 650, may be disposed within the enclosed space to absorb exudate from the wound bed. Periodically changing pressure p₀Accordingly, the wound bed may be expanded into the enclosed space from the baseline state to the expanded state and released from the expanded state back to the baseline state, whereby the wound bed may be alternately brought into contact with the pad, exudate from the wound bed transferred into the pad, and the wound bed and pad are disconnected from contact to prevent the pad and the wound bed from sticking together. When pressure p is₀In the case of a periodic variation, multiple gaseous fluids may be input to or derived from the enclosed space through the port or the second port. Exudate may be drained from the enclosed space through a port in fluid communication with the pad. The exudate may be captured in a container of the control module, such ascontainer 881.

The wound bed in the enclosed space may be viewed through a cover, such ascover 40, 140, 240, 340, 440, which may be at least partially formed of a transparent material. Windows, such aswindows 139a, 139b, 139c, 139d, may be provided on the wound therapy device to allow viewing of the wound bed within the enclosed space. In certain embodiments, the cover may be in an open position, such asopen position 46, and a closed position, such asclosed position 48, to respectively allow direct access to, or seal closed, an enclosed space including a wound bed.

The dressing may be omitted from the wound bed at least during part of the healing process. The absence of a dressing in constant contact with the wound bed may allow the wound treatment apparatus to be used throughout, and even until the final stage of healing of the wound bed, may allow the wound bed to be viewed through the wound interface. During the healing process, a portion of the wound treatment device, such as the pad, may be replaced, or the entire wound treatment device replaced, as desired. The wound therapy device is removed after the wound bed has healed.

Fig. 15 provides anexemplary method 1500 of use of the wound treatment apparatus disclosed herein. Atstep 1501,method 1500 begins. Atstep 1505, the wound interface is secured to the skin, thereby closing the wound bed through the enclosed space.

Atstep 1510, fluid is directed out of the enclosed space, thereby inflating the wound bed into communication with a pad disposed within the enclosed space. Exudate may be conducted from the wound bed into the pad. Pressure drop p₀-＞p_minThe capillaries close to the wound bed are in an expanded state.

Atstep 1515, exudate is directed out of the pad through the port. A periodic negative pressure may be applied to draw exudate from the pad.

Atstep 1520, fluid is introduced into the enclosed space to increase the pressure p₀-＞p_maxThereby retracting the wound bed from the enclosed space out of communication with the pad. The fluid input instep 1520 may be a liquid or a gas, and if a gas, may have an oxygen concentration greater than atmospheric air (greater than 20.95% by volume).

Atstep 1525,steps 1510, 1515, 1520 are repeated, thereby massaging the wound bed.Steps 1510, 1515, 1520 may be repeated for a period of time, such as about 5 minutes or about 6 minutes.Exemplary method 1500 terminates atstep 1529.

Thus, a method of using a wound therapy device may comprise the steps of: sealingly securing a wound interface to the skin surface along the periphery of the wound bed to form a fluid-tight enclosure and enclosing the wound bed to the skin surface, wherein the wound interface has sufficient resistance to deformation to maintain the enclosure when a pressure p within the enclosure is present₀Sufficiently below ambient pressure p_ambAt least a portion of the contained wound bed expands into the enclosed space. The use method can comprise the following steps: make itAbsorbing exudate from the wound bed with a pad disposed within the enclosed space, and directing the exudate from the pad via a port disposed at the wound interface. The use method can comprise the following steps: alternately, fluid (gas or liquid) is input into the enclosed space through the port and then removed through the port. The use method can comprise the following steps: fluid (gas or liquid) is input into the enclosed space through the port and liquid is output through the second port. The use method can comprise the following steps: varying the pressure p in the enclosed space₀So that at least a portion of the wound bed is sufficiently rhythmically expanded into the closed space cavity, which can produce surging blood flow and micro-deformation of the wound bed, beneficial to healing. The use method can comprise the following steps: the wound bed is inflated into communication with the pad for removing exudate from the wound bed, and then the wound bed is disconnected from communication with the pad. The use method can comprise the following steps: the wound interface is sealingly conformable secured to the skin surface surrounding the wound bed using an annular cushion biased along the skin surface surrounding the wound. The use method can comprise the following steps: the wound interface is sealingly conformably secured to the skin surface surrounding the wound bed using an apron disposed over the wound interface. The use method can comprise the following steps: the cover portion of the wound interface is positioned between the sealed position and the open position, thereby allowing direct intervention into the enclosed space. The use method can comprise the following steps: the wound bed was observed through the transparent portion of the wound interface. The use method can comprise the following steps: the use or non-use of a pad or dressing associated with the wound bed is selected. The use method can comprise the following steps: will be the pressure p in the enclosed space₀Evenly distributed over the wound bed, thereby reducing uneven pressure gradients that may lead to reduced blood flow near the wound boundary. The use method can comprise the following steps: a range of other therapies (including various liquids and gases) and incubation of biological materials, such as tissue matrix or skin grafts, are delivered over a range of pressures from positive to negative pressure. The use method can comprise the following steps: the wound treatment device is used in a number of possible ways in human or veterinary applications for the following situations: acute and chronic wounds, prevention of surgical site infection and increased rates of chemotherapy response.

Although the foregoing discussion has focused on wound care, the wound treatment devices disclosed herein may have beneficial applications in other areas of human and veterinary medicine. For example, in chemotherapy for cancer treatment, many drugs are not selective enough to kill only tumor cells. However, by selectively increasing the metabolism of tumor cells, higher killing rates can be achieved during the use of chemotherapy. An effective way to increase metabolic rate is to raise body temperature, but raising body temperature throughout the body is not feasible and harmful, similar to fever. However, at least for the treatment of tumors on opposite surfaces, such as skin and breast cancer, it is entirely feasible to place a wound interface of appropriate shape and size at the tumor site, with chemotherapy, injecting very warm fluids (e.g., 42 ℃ or 107 ℃ F.) at much higher temperatures than when clinical fever is highest. When the chemotherapeutic drug is circulating, the kill rate should be higher for tumors that have been subjected to such localized hyperthermia.

The foregoing discussion discloses and describes various exemplary applications in connection with the accompanying drawings. These applications are not intended to limit the scope of coverage, but, rather, to assist in understanding the context of the language used in the specification and claims. Having studied the disclosure and the illustrative applications herein, one of ordinary skill in the art will readily recognize various changes, modifications and variations which may be made therein without departing from the spirit and scope of the invention as defined in the following claims.

Claims (23)

1. An apparatus, comprising:

a wound interface resistant to deformation sealably affixed to a skin surface to form a fluid-tight enclosure enclosing a wound boundary of a wound bed;

a port disposed on the wound interface in fluid communication with the enclosed space for conducting fluid from the enclosed space to create a pressure within the enclosed space that is less than ambient pressure p_ambPressure p of₀(ii) a And

in the expanded state, whenThe wound bed is at less than ambient pressure p when the wound interface is sealingly secured to the skin surface_ambPressure p of₀And expanding through an enclosed space inlet into the enclosed space, the expanded state comprising at least a portion of the expanded wound bed.

2. The apparatus of claim 1, further comprising:

a pad receivable within the enclosed space to absorb exudate from the wound bed through intermittent contact therewith, the pad received within the enclosed space being at least intermittently in fluid communication with the port through which the exudate is conducted away from the pad.

3. The device of claim 2, wherein the pad comprises a material selected from the group consisting of: polyvinyl alcohol, polyurethane, aliphatic polyamide fibers, semi-aromatic polyamide fibers, and polyester fibers.

4. The apparatus of claim 1, further comprising:

a pad receivable within the enclosed space to absorb exudate from the wound bed by varying the degree of engagement with the wound bed, the pad being in at least intermittent fluid communication with the port through which the exudate is conducted away from the pad.

5. The apparatus of claim 1, further comprising:

at p_min≤p₀≤p_maxPressure p varying periodically within the pressure range₀The pressure p when the wound interface is sealingly secured to the skin surface₀Causes the wound bed to change between the expanded state and a baseline state to massage the wound bed.

6. A wound treatment apparatus comprising:

a wound interface sealably secured to a skin surface surrounding a wound bed to enclose a wound boundary of the wound bed within a fluid-tight enclosure when a pressure p within the enclosure is present₀Less than ambient pressure p_ambThe wound interface has sufficient resistance to deformation to expand at least a portion of the wound bed into the enclosed space;

a port disposed on the wound interface in fluid communication with the enclosed space to provide pressure over the pressure range p_min≤p₀≤p_maxPeriodically varying the pressure p within the enclosed space₀Wherein p is_min≤p_amb(ii) a And

a pad contained within the enclosed space for absorbing exudates from the wound bed, the pressure p₀The change in pressure expands the wound bed into communication with the pad and releases the wound bed from communication with the pad.

7. The device of claim 6, wherein the pressure p_maxApproximately equal to ambient pressure p_amb。

8. The device of claim 6, wherein the port is in at least intermittent fluid communication with the pad for directing exudate away from the pad.

9. The device of claim 6, wherein the pad comprises woven fibers of polyester fibers having predominantly hydrophobic on the surface and nylon fibers having predominantly hydrophilic on the interior, the woven fibers being in contact with the outlet port point to serve as a conduit for fluid transfer.

10. The device of claim 6, wherein the pad comprises a material selected from the group consisting of: polyvinyl alcohol, polyurethane, aliphatic polyamide fiber, semi-aromatic polyamide fiber, and polyester fiber.

11. The apparatus of claim 6, further comprising:

a void formed by the wound interface, the pad being placed within the void; and

one or more channels between the enclosed space and the void for transferring exudate from the wound bed to the pad.

12. The apparatus of claim 6, wherein the pad is replaceably received within the wound interface.

13. The apparatus of claim 6, wherein the wound interface further comprises:

a lid positionable between a sealing engagement position and an open engagement position, the open engagement position allowing direct access to the enclosed space.

14. The apparatus of claim 6, wherein the wound bed is visible through a transparent portion of the wound interface.

15. The apparatus of claim 6, the wound interface further comprising:

a cushion forming a closed annular perimeter, the cushion comprising an inflatable bladder or closed cell foam, the cushion being sealingly adhesively secured to the skin surface to sealingly secure the wound interface to the skin surface.

16. The apparatus of claim 6, the wound interface further comprising:

a skirt extending forwardly to form a closed perimeter for conformably securing said wound interface seal to said skin surface.

17. The apparatus of claim 6, the wound interface further comprising:

a flange disposed distal to the outer surface of the wound interface to conformably seal the wound interface to the skin surface, the flange operable to hold the pressure p within the enclosed space₀The resulting force is distributed to the skin surface.

18. The apparatus of claim 6, wherein the wound interface is sealingly securable to a skin surface of an oval or elongated shaped area along the wound boundary of the wound bed.

19. The apparatus of claim 6, comprising:

a capillary, the capillary being proximate to the wound bed, the capillary having an increased blood flow above a baseline when the wound bed is in an expanded state.

20. The apparatus of claim 6, comprising:

capillary vessels, close to the wound bed, passing said pressure p within said enclosed space₀In said pressure range p_min≤p₀≤p_maxAnd (c) periodically alternating, the capillaries correspondingly alternating between an expanded state and a non-expanded state as the wound bed alternates between an expanded state and a baseline state.

21. A wound treatment apparatus comprising:

a wound interface sealingly secured to a skin surface surrounding a wound bed to enclose a wound boundary of the wound bed within a fluid-tight enclosed space, a pressure p within the enclosed space₀Less than ambient pressure p_ambThe wound interface has sufficient resistance to deformation to expand at least a portion of the wound bed into the enclosed space;

a port disposed on the wound interface in fluid communication with the enclosed spaceCommunication for the pressure range p_min≤p₀≤p_maxPeriodically varying the pressure p within the enclosed space₀Wherein p is_min≤p_amb(ii) a And

a pad contained within the enclosed space for absorbing exudate from the wound bed, the pressure p₀The change in pressure expands the wound bed into communication with the pad and releases the wound bed from communication with the pad.

22. The wound treatment apparatus of claim 21, wherein the pressure p within the enclosed space₀In said pressure range p_min≤p₀≤p_maxPeriodically, with a period of less than about 6 minutes.

23. The wound treatment apparatus of claim 21, wherein the pressure p_maxIs generally greater than or equal to said ambient pressure p_amb。

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