Oxygen-controlled negative pressure wound therapy device

Abstract

A system for negative pressure and hypoxic tissue treatment includes a chemical pump assembly, a dressing covering a tissue site, a plurality of hoses, and a cover layer covering a portion of the dressing. Each hose is configured to fluidly connect the dressing to the assembly. Oxygen flows from the dressing to a reactor within the assembly, where the oxygen is consumed. The hoses have different cross-sectional areas and selectable lengths that can be selected to provide a desired amount of oxygen around the tissue site. The cover layer, which is less permeable to air than the dressing, can be used to cover a portion of the dressing to prevent air from entering through the dressing and provide a desired amount of oxygen around the tissue site.

Description

[Technical Field]

[0001] Negative pressure therapy is a treatment method that utilizes "negative pressure" to treat and heal the skin. "Negative pressure" is a term that describes pressure lower than normal atmospheric pressure. Negative pressure therapy is used on several skin sites, including wounds and cuts. Additionally, negative pressure therapy is useful for treating wounds with complex healing processes. Additionally, negative pressure therapy can be used for cosmetic purposes, such as wrinkle reduction. [Background technology]

[0002] Negative pressure therapy is generally achieved by maintaining a reduced pressure underneath the dressing over the treatment area. A vacuum source, such as a pump, applies a reduced pressure inside the dressing over the treatment area. Summary of the Invention

[0003] A system for controlling the amount of oxygen in an enclosed space includes a dressing configured to seal tissue to define an enclosed space between the dressing and the tissue, a housing defining an interior chamber and including a reactor disposed within the interior chamber configured to chemically react with oxygen in the interior chamber, and a fluid passageway connecting the interior chamber and the enclosed space to allow oxygen to flow between the interior chamber and the enclosed space, wherein the system is configured to allow a user to control the amount of oxygen in the enclosed space by selecting a length of the fluid passageway, selecting a cross-sectional area of ​​the fluid passageway, selecting an oxygen permeability of the dressing, or a combination thereof.

[0004] A method for controlling the amount of oxygen in an enclosed space includes at least one of a first hose, a plurality of hoses, a second hose, a clamp, and a cover layer. The enclosed space is defined by a dressing sealed against tissue. A fluid passage connects the enclosed space to an internal chamber of a housing. A reactor is disposed within the internal chamber and configured to chemically react with oxygen within the internal chamber. The first hose at least partially defines the fluid passage and is configured to be selectively changed from an original length to a changed length shorter than the original length, thereby controlling the amount of oxygen in the enclosed space. The plurality of hoses have different cross-sectional areas. Each of the plurality of hoses is configured to be selectively connected to the housing and the dressing, thereby at least partially defining the fluid passage and thus controlling the amount of oxygen in the enclosed space. The second hose at least partially defines the fluid passage. The clamp is configured to selectively change the cross-sectional area of ​​the second hose, thereby controlling the amount of oxygen in the enclosed space. The cover layer has a lower permeability to air than the dressing and is configured to cover at least a portion of the dressing to control the amount of oxygen within the enclosed space. [Brief explanation of the drawings]

[0005] [Figure 1] Figure 1 is a perspective view of a chemical pump assembly. [Figure 2] FIG. 2 is another perspective view of the chemical pump assembly. [Figure 3] Figure 3 is an exploded perspective view of the chemical pump assembly. [Figure 4] FIG. 4 is another exploded perspective view of the chemical pump assembly. [Figure 5] FIG. 5 is a perspective view of the chemical pump assembly after the first and second pull tabs have been removed. [Figure 6] FIG. 6 is a perspective view of a chemical pump assembly including a valve. [Figure 7]FIG. 7 is a perspective view of a chemical pump assembly fluidly connected to a dressing. [Figure 8] FIG. 8 is a perspective view of the lower housing of the chemical pump assembly. [Figure 9] Figure 9 shows cross sections of various sizes of hoses for connecting to the chemical pump assembly. [Figure 10] FIG. 10 is a perspective view of various size adapters for use with the hose of FIG. 9. [Figure 11] Figure 11 is a perspective view of the hose with markings. [Figure 12] Figure 12 is a perspective view of a clamp for sealing a hose. [Figure 13] FIG. 13 is a perspective view of another clamp for sealing a hose. [Figure 14] FIG. 14 is a cross-sectional view of a hose having a porous solid. DETAILED DESCRIPTION OF THE INVENTION

[0006] FIG. 1 illustrates a chemical pump assembly 12 system or method useful for negative pressure therapy. As used herein, "negative pressure" refers to pressure below atmospheric pressure. The chemical pump assembly 12 is configured to connect to a dressing 14 that is applied to the skin S and is in fluid communication with the enclosed space below the dressing 14. An example of a dressing 14 that can be used with the chemical pump assembly 12 is described in U.S. Patent Application Serial No. 16 / 114,813.

[0007] The chemical pump assembly 12 generally includes a chemical pump housing 16, which includes an upper housing 18 and a lower housing 20 that connect to define an internal chamber 22 ( FIG. 3 ) therebetween. In one embodiment, the upper housing 18 and the lower housing 20 may be constructed as separate elements. If the upper housing 18 and the lower housing 20 are separate elements, the upper housing 18 and the lower housing 20 are joined together, forming a seam 24 between the upper housing 18 and the lower housing 20. When the upper housing 18 and the lower housing 20 are joined, an airtight seal is formed at the seam 24 between the upper housing 18 and the lower housing 20. As a result, gas cannot enter or escape from the internal chamber 22 of the chemical pump housing 16 through the seam 24. In another embodiment, the upper housing 18 and the lower housing 20 may be integrally formed. Additionally, the upper housing 18 may include an upper interior wall surface 26 that is substantially planar with only a slight curve, as shown in FIG. 4 . The lower housing 20 may include a lower inner wall 28 that is offset from the side wall of the lower housing 20 .

[0008] The lower housing 20 may further include a channel 32 disposed around the inner periphery of the lower housing 20, as shown in FIG. 3. The channel 32 may surround the entire inner periphery of the lower housing 20, or may surround only a portion of the inner periphery of the lower housing 20. Furthermore, the channel 32 may consist of a single channel or multiple channels. The channel 32 may also be disposed between the side wall of the lower housing 20 and the lower inner wall 28. The upper housing 18 may include a ridge 34 disposed around the inner periphery of the upper housing 18, as shown in FIG. 4. The ridge 34 may surround the entire inner periphery of the upper housing 18, or may surround only a portion of the inner periphery of the upper housing 18. The ridge 34 may also consist of a single ridge or multiple ridges. Alternatively, the ridge 34 may be disposed in the lower housing 20, and the channel 32 may be disposed in the upper housing 18.

[0009] When the upper and lower housings 18, 20 are joined, the ridges 34 are configured to be inserted into the channels 32. When the ridges 34 are inserted into the channels 32, the upper and lower housings 18, 20 can fit together, forming an airtight seal to prevent gas from passing through the seam 24. The upper and lower housings 18, 20 may be connected in other known ways to form an airtight seal at the seam 24.

[0010] Chemical pump assembly 12 further includes chemical pump 36 (FIG. 4). Chemical pump 36 is disposed in interior chamber 22 of chemical pump housing 16 prior to connecting upper housing 18 and lower housing 20. In the illustrated embodiment, chemical pump 36 in chemical pump assembly 12 is a reactor configured to chemically react with a selected gas, such as oxygen in air. Examples of reactors that can be used in chemical pump assembly 12 are described in U.S. Patent Application Publication No. 2014 / 0109890A1 and International Patent Application No. PCT / US2016 / 059364.

[0011] In the illustrated embodiment, an opening 40 in the form of an elongated slit is provided on the upper housing 18. The opening 40 is preferably located toward the distal side of the upper housing 18. However, the opening 40 may also be located toward the proximal side of the upper housing 18 or elsewhere on the chemical pump housing 16. When the opening 40 is uncovered, the opening 40 exposes the internal chamber 22 to the ambient atmosphere. The upper housing 18 may also include a sloping wall 42 adjacent the opening 40 that slopes upward from the internal chamber 22 toward the outer surface and toward the distal side of the upper housing 18.

[0012] 2, at least one pull tab extends circumferentially from interior chamber 22 through opening 40. In one embodiment, the at least one pull tab includes a first pull tab 44 and a second pull tab 46. In one embodiment, first pull tab 44 and second pull tab 46 are separate elements, while in other embodiments, first pull tab 44 and second pull tab 46 may be connected, i.e., integral.

[0013] 3 and 4 , packet 48 includes a removable layer 50 that covers chemical pump 36, preventing exposure of chemical pump 36 to the ambient atmosphere or air within inner chamber 22 until removable layer 50 is removed from packet 48. Packet 48 may be a foil packet that creates a sealed environment around chemical pump 36. First pull tab 44 extends through opening 40 and is connected to removable layer 50. First pull tab 44 may be pulled to remove first pull tab 44 from opening 40. When first pull tab 44 is pulled through opening 40, removable layer 50 is removed from packet 48 and, optionally, from inner chamber 22 through opening 40, exposing chemical pump 36 to the ambient atmosphere. After removable layer 50 is removed, chemical pump 36 initiates a chemical reaction with a selected gas, such as oxygen, within inner chamber 22. Because of the slope of the angled wall 42, the first pull tab 44 and the removable layer 50 are easily removed from the opening 40. The first pull tab 44 is preferably removed after the chemical pump assembly 12 is connected to the dressing 14. However, the first pull tab 44 may be removed before the chemical pump assembly 12 is attached to the dressing 14.

[0014] In the illustrated embodiment, the packet 48 is affixed to the upper interior wall surface 26 of the upper housing 18 via adhesive. The packet 48 may be affixed to other surfaces, if desired. The removable layer 50 is covered on its upper side (in the orientation shown in FIG. 3 ) with adhesive, except for a small portion 52 on the end of the removable layer 50 opposite the opening 40, thereby attaching the removable layer 50 to the packet 48. The upper side of the removable layer 50 is the side that faces the packet 48. The first pull tab 44 is connected to this small portion 52 that is free of adhesive, and the connection between the first pull tab 44 and the removable layer 50 is limited to the small portion 52 in that the first pull tab 44 is free to move relative to the remainder of the removable layer 50, which has adhesive on its upper side and is affixed to the packet 48. Removable layer 50 may be kiss cut (rather than cut through) to define a portion of removable layer 50 that will be torn away from the remaining portion of removable layer 50. As such, when first pull tab 44 is pulled through opening 40 and away from chemical pump housing 16, removable layer 50 is severed at the kiss cut, and the portion that will be torn away wraps around itself as it is peeled away from packet 48 to which it is still attached.

[0015] Chemical pump assembly 12 further includes a cover, such as membrane 62, described below, for sealing opening 40 to prevent air from entering interior chamber 22 through opening 40 after removable layer 50 is removed. Other types of covers, such as films not yet connected to chemical pump housing 16, may also be employed.

[0016] The second pull tab 46 is positioned over a portion of the top surface of the upper housing 18 and cooperates with a membrane 62 adhered thereto. The membrane 62 includes a flap 64, and as shown in FIG. 2 , the opening 40 is located beneath the flap 64. The second pull tab 46 is connected to a release layer 66 disposed on the underside of the membrane 62. The release layer 66 covers the adhesive (not visible in FIG. 2 ) on the underside of the membrane 62. Referring to FIG. 4 , a slit 68 is provided in the release layer 66, allowing a portion of the release layer 66 to be removed to expose the adhesive before attaching the membrane 62 to the top surface of the upper housing 18, while leaving a portion of the release layer 66 beneath the flap 64. When the second pull tab 46 is pulled, the second pull tab 46 separates the release layer 66 from the flap 64, exposing the adhesive on the underside of the flap 64. The flap 64 then moves toward the upper housing 18, covering the remaining portion of the top surface of the upper housing 18 and thus also covering the opening 40. As a result, the internal chamber 22 is no longer exposed to the ambient atmosphere through the opening 40. In the illustrated embodiment, the thin film 62 is metalized to prevent air from entering the internal chamber 22 when the internal chamber 22 is under negative pressure. To prevent air from entering, the thin film 62 may be a metalized polymer film including a metal layer disposed on a polymer film (e.g., polyester, polyethylene, polypropylene, polylactic acid, polyimide, fluoropolymer, polyether ether ketone, polyvinylidene chloride, ethylene vinyl alcohol, nylon, polyethylene terephthalate). The metal may be a metal foil or coating layer and may have a thickness of, for example, 10 nm to 10 μm. The metal layer may include various metals, such as aluminum, nickel, copper, or chromium. The metal layer may be laminated with the polymer film or coated on the polymer film. Coating the metal layer on the polymer film may be achieved by various vapor deposition methods, such as physical vapor deposition methods, including various vacuum deposition methods. The metallized polymer film may include additional layers, such as a protective layer, over the metal layer.

[0017] When the membrane 62 covers the opening 40, the chemical pump 36 chemically reacts with the selected gas in the enclosed space below the dressing, forming a closed system if already connected to the dressing via a hose 82 (schematically shown in phantom in FIGS. 1, 7, and 6). Thus, the pressure in the enclosed space decreases. When the internal chamber 22 is under negative pressure, the membrane 62 is drawn toward the internal chamber 22 through the opening 40 (see FIG. 5). Thus, the membrane 62 cooperating with the opening 40 can provide an indicator to the user that the internal chamber 22 is under negative pressure. An indicator 70, such as a line or cross, may also be provided on the membrane 62 near the opening 40 to further indicate negative pressure.

[0018] The chemical pump housing 16 further includes a hose fitting 76, which in the illustrated embodiment is a barbed fitting for securely fastening a hose 82 to the hose fitting 76. The hose fitting 76 is tubular and includes a passageway 78 that communicates with the interior chamber 22. In one embodiment, the hose fitting 76 is located on the side of the chemical pump housing 16 opposite the opening 40. The hose fitting 76 may be located on a recess 80 in the chemical pump housing 16, although the hose fitting 76 may be located on any surface of the chemical pump housing 16. Alternatively, the recess 80 may be located on any surface of the chemical pump housing 16. A hose 82 (shown schematically) is attached to the hose fitting 76 to connect the chemical pump assembly 12 to the dressing 14.

[0019] Referring back to FIG. 1 , the chemical pump assembly 12 may further include a mounting pad 92 disposed below and connected to the lower housing 20. The mounting pad 92 includes a lower side 94 and an upper side 96. A fastener 98, such as a hook and loop fastener, may be disposed on the upper side 96 of the mounting pad 92 for connecting with a hook and loop fastener 100 received in a recess 102 disposed in the bottom surface of the lower housing 20 to attach the mounting pad 92 to the chemical pump housing 16. The mounting pad 92 may be larger than the chemical pump housing 16. The lower side 94 of the mounting pad 92 is configured to be attached to a surface, such as a gown or garment worn by a patient. The mounting pad 92 may include an adhesive layer disposed on the lower side 94. A removable mounting pad release liner 104 may be disposed on the adhesive. The removable mounting pad release liner 104 is removed to expose the adhesive.

[0020] A method for operating the chemical pump assembly 12 is described below. At least one dressing 14 may be placed on a tissue site and seal against the tissue surrounding the tissue site, thereby defining an enclosed space between the dressing 14 and the tissue. The chemical pump assembly 12 may then be connected to the at least one dressing 14 via a hose 82. When the chemical pump assembly 12 is connected to the at least one dressing 14 via the hose 82, the internal chamber 22 of the chemical pump assembly 12 is in fluid communication with the enclosed space defined by the dressing 14. That is, the hose 82 is connected to the dressing 14 and the chemical pump assembly 12, at least partially defining a fluid passage between the enclosed space and the internal chamber 22. The desired amount of oxygen needed within the enclosed space may be controlled by adjusting the length of the hose 82, adjusting the cross-sectional area of ​​the hose 82, or covering a portion of the dressing 14 with a breathable cover layer 15 that is smaller than the dressing 14.

[0021] Either pull tab 44 or 46 may be pulled. When the first pull tab 44 is pulled through the opening 40, the removable layer 50 is removed from the packet 48. As a result, the chemical pump 36 within the chemical pump housing 16 is exposed to the ambient atmosphere, as well as the air within the internal chamber 22, and begins to react with the selected gas. Pulling the second pull tab 46 removes the release layer 66 on the bottom surface of the flap 64, exposing the adhesive on the bottom surface. The flap 64 is then brought toward the upper housing 18, covering the opening 40 with the thin film 62. As a result, the internal chamber 22 is no longer exposed to the ambient atmosphere. The reactor (chemical pump 36) then chemically reacts with the selected gas within the internal chamber 22 and the enclosed space beneath the dressing 14, reducing the pressure at the tissue site.

[0022] 6 shows chemical pump housing 16 including a valve, which may be two-way valve 106. It should be noted that to accommodate two-way valve 106, chemical pump 36 and packet 48 may need to be reduced in size or chemical pump housing 16 may need to be increased in size. Two-way valve 106 may be of a similar construction to the valve described in U.S. Pat. No. 5,439,143. The two-way valve 106 may be configured such that (1) when the air pressure outside the two-way valve 106 is equal to or less than the air (or gas) pressure in the internal chamber 22, the two-way valve 106 opens, allowing air to be drawn from the internal chamber 22 through the two-way valve 106; (2) when the ambient air pressure is greater than the air (or gas) pressure in the internal chamber 22 by a predetermined difference (e.g., 200 mmHg) or more, the two-way valve 106 opens, allowing air to enter the internal chamber 22 through the two-way valve 106; or (3) otherwise, the two-way valve 106 remains closed, preventing air from entering or leaving the internal chamber 22 through the two-way valve 106. When the internal chamber 22 is in this third state, the enclosed space below the dressing 14 is in a therapeutic range, e.g., a pressure offset of -40 mmHg to -200 mmHg from ambient atmosphere (e.g., 560 to 710 mmHg absolute at sea level). Optionally, a mechanical pump assembly 108, more fully described in PCT / US2019 / 12298, may be inserted into the two-way valve 106 and operated to create a negative pressure in the enclosed space below the dressing 14 when the two-way valve 106 is opened and the chemical pump assembly 12 is connected to the dressing via the hose 82. A conventional wall suction pump, sometimes referred to as "wall suction," may also be connected to the two-way valve 106 to create a negative pressure in the enclosed space below the dressing 14 when the two-way valve 106 is opened and the chemical pump assembly 12 is connected to the dressing via the hose 82.

[0023] Instead of the two-way valve 106, two one-way valves may be employed. One of the one-way valves may be configured to open when the air pressure outside the one-way valve is lower than the air (or gas) pressure in the internal chamber 22, allowing gas to be drawn through the one-way valve. The other one-way valve may be configured to open when the ambient air pressure is greater than the air (or gas) pressure in the internal chamber 22 by a predetermined difference (e.g., 200 mmHg) or more, allowing air to enter the internal chamber 22 through the one-way valve. When the air pressure in the internal chamber 22 is in the therapeutic range, e.g., -40 mmHg to -200 mmHg offset from ambient atmosphere (560 to 710 mmHg absolute at sea level), both one-way valves remain closed. A mechanical pump assembly 108 , wall suction, or similar mechanical suction device may cooperate with a one-way valve to allow air to enter the inner chamber 22 .

[0024] The amount of oxygen in the enclosed space defined between the dressing 14 and the skin S is determined based on the flow of oxygen through the fluid pathway from the enclosed space to the internal chamber 22 (i.e., fluid pathway conductance) and the oxygen permeation from the ambient environment into the enclosed space through the exposed surface of the dressing 14. Thus, the amount of oxygen in the enclosed space, which is a function of the amount of oxygen passing through the dressing 14, can be controlled by adjusting the area of ​​the dressing 14 covered by the cover layer 15. Furthermore, the amount of oxygen in the enclosed space, which is a function of the fluid pathway conductance, can be controlled by adjusting the length of the fluid pathway and adjusting the minimum cross-sectional area of ​​the fluid pathway.

[0025] Referring to Figures 7-8, a fluid pathway between the enclosed space and the internal chamber 22 may be cumulatively defined by the hose coupling 76, the hose 82, and the dressing coupling 84 on the peripherally exposed surface of the dressing 14. As this oxygen flow increases through the fluid pathway (driven by oxygen consumption by the chemical pump 36), the amount of oxygen in the enclosed space may decrease. The flow of oxygen from the enclosed space to the internal chamber 22, driven by the oxygen partial pressure gradient between the internal chamber 22 and the enclosed space, may be a function of the minimum cross-sectional area (in a plane perpendicular to the length) of the fluid pathway between the enclosed space and the internal chamber 22, as well as the length of the fluid pathway. Fluid pathway conductance depends not only on the minimum cross-sectional area but also on all cross-sectional areas and, of course, the length of each particular region segment. The flow or diffusion of oxygen through the hose 82 is driven by the pressure gradient between the enclosed space and the internal chamber and limited by the fluid pathway's resistance to flow. The fluid pathway may be considered to have three or more sections with different resistances to flow: the resistance of the hose fitting 76 (R1), the resistance of the hose 82 (R2), and the resistance of the dressing fitting 84 (R3). If a restriction is added to a portion of the hose 82 to reduce its cross-section, there may be a fourth section (R4) with a different resistance to flow, which may be zero if the hose 82 has no additional restrictions. The total resistance of the fluid pathway to flow is the sum of the resistances of the individual sections (just as the electrical resistance of a circuit of resistors in series is equal to the sum of the individual resistors) and can be expressed as follows: Rtotal = R1 + R2 + R3 + R4

[0026] The resistance to flow, Ri, is proportional to the length of the fluid passage, li, divided by its cross-sectional area, Ai: Ri ∝ li / Ai. The flow rate is proportional to the fluid passage conductance, G = 1 / R, so G = 1 / Rtotal ∝ 1 / (R1 + R2 + R3 + R4).

[0027] The relative magnitudes of Ri determine whether one Ri dominates the conductance G. Even if the length of the minimum cross-sectional area is short enough, the resistance of the rest of the hose may still dominate, although it will be less than without the clamp.

[0028] As will be appreciated, any minimum cross-sectional area along the length of a fluid pathway can, to a large extent, be a limiting factor in the flow of fluid pathway conductance, e.g., due to a bottleneck effect, even if other portions of the fluid pathway have larger internal cross-sectional areas. Thus, a change in the minimum cross-sectional area of ​​the fluid pathway and / or a change in the overall length of the fluid pathway, or a change in the cross-sectional area of ​​the remainder of the fluid pathway, can result in a change in the flow of oxygen from the enclosed space to the chemical pump 36, resulting in a corresponding change in the amount of oxygen in the enclosed space around the tissue site. If the dressing is rigid, a decrease in the amount of oxygen in the enclosed space can result in a change in pressure within the enclosed space, i.e., can create a negative pressure within the enclosed space.

[0029] Thus, the present invention provides a system for negative pressure and hypoxic tissue treatment that allows a user to select the minimum cross-sectional area of ​​the fluid passage and / or the length of the fluid passage to create a desired amount of oxygen within an enclosed space that corresponds to one of various predetermined oxygen amounts in the enclosed space.

[0030] FIG. 7 illustrates a chemical pump assembly 12 similar to that described herein with respect to FIGS. 1-6, but with modifications regarding the size of the hose coupling 76 and corresponding passageway 78, and the dressing coupling 84 and corresponding opening 85 to the enclosed space. As shown, the hose coupling 76 has a larger internal cross-sectional area (i.e., the cross-sectional area of ​​the passageway 78) and the dressing coupling 84 has a larger internal cross-sectional area (i.e., the cross-sectional area of ​​the opening 85) than those shown in FIGS. 1 and 3-4. The larger hose coupling 76 and dressing coupling 84 may be used with a hose 82 having a corresponding enlarged internal cross-sectional area, which may be equal to the internal cross-sectional area of ​​the hose coupling 76 (i.e., the cross-sectional area of ​​the passageway 78) and the internal cross-sectional area of ​​the dressing coupling 84 (i.e., the cross-sectional area of ​​the opening 85). One end of the hose 82 may be connected to the hose coupling 76, and the other end of the hose 82 may be connected to the dressing coupling 84.

[0031] The hose fitting 76, the hose 82, and the dressing fitting 84 may collectively define a fluid passageway between the interior chamber 22 of the chemical pump assembly 12 and the enclosed space defined by the dressing 14 and the skin S. The hose 82 may be connected to the hose fitting 76 and the dressing fitting 84 by fitting an end of the hose 82 around the hose fitting 76 and the dressing fitting 84. This connection may be achieved by a compression fit between the inner surface of the hose 82 and the outer surfaces of the hose fitting 76 and the dressing fitting 84. The hose fitting 76 and the dressing fitting 84 may also be hooked on their outer surfaces, which may seal against the inner surface of the hose 82 and prevent the hose 82 from becoming dislodged therefrom. In this scenario, the internal cross-sectional area of ​​either the hose fitting 76 or the dressing fitting 84 may be smaller than the internal cross-sectional area of ​​the hose 82, such that the end of the hose 82 can fit around the hose fitting 76 and the dressing fitting 84, defining a minimum cross-sectional area for a fluid passage between the space enclosed thereby and the internal chamber 22. Alternatively, each end of the hose 82 may be slightly flared to have a larger internal cross-sectional area than the central portion of the hose 82, such that the end of the hose 82 can be connected to the hose fitting 76 and the dressing fitting 84 by fitting around them. In this alternative scenario, the internal cross-sectional area of ​​the central portion of the hose 82 may be the same as the internal cross-sectional area of ​​both the hose fitting 76 and the dressing fitting 84. In this manner, the minimum cross-sectional area of ​​the fluid passage between the enclosed space and the internal chamber 22 may be defined by the central portion of the hose 82, the hose fitting 76, and the dressing fitting 84, as each of these has the same internal cross-sectional area.

[0032] The hose 82 may be connected to the hose fitting 76 and the dressing fitting 84 by fitting within the hose fitting 76 and the dressing fitting 84. This connection may be achieved with a compression fit that forms a seal between the outer surface of the hose 82 and the inner surfaces of the hose fitting 76 and the dressing fitting 84. In this scenario, the interior cross-sectional area of ​​the hose 82 may be smaller than the interior cross-sectional area of ​​either the hose fitting 76 or the dressing fitting 84, which may therefore define the minimum cross-sectional area for the fluid passage between the enclosed space and the interior chamber 22.

[0033] The hose 82 may also be connected to the hose fitting 76 and the dressing fitting 84 by abutting them. This connection may be achieved by using two connector sheaths into which the ends of the hose 82 and the hose fitting 76 and the dressing fitting 84 are placed so that the connector sheaths surround each end of the hose 82 and the hose fitting 76 and the dressing fitting 84 to form a compression fit. In this scenario, the internal cross-sectional area of ​​the hose 82 may be the same as the internal cross-sectional area of ​​both the hose fitting 76 and the dressing fitting 84; therefore, the minimum cross-sectional area of ​​the fluid passage between the enclosed space and the internal chamber 22 is defined by the hose 82, the hose fitting 76, and the dressing fitting 84, respectively.

[0034] In either case, the minimum cross-sectional area of ​​the fluid passage is expanded to be larger than that shown in Figures 1 and 3-4. As such, the fluid passage conductance (i.e., the flow of a selected gas, such as oxygen, from the enclosed space to the inner chamber 22) may be increased compared to when the minimum cross-sectional area of ​​the fluid passage is smaller, for example, as shown in Figures 1 and 3-4, thereby increasing the flow of oxygen from the enclosed space to the inner chamber 22.

[0035] As will be appreciated, the cross-sectional areas of the passageway 78 and opening 85 may be fixed; therefore, the minimum internal cross-sectional area of ​​the hose 82 used may determine the effective cross-sectional area of ​​the fluid passageway. Accordingly, the flow of oxygen through the fluid passageway may be determined based on the minimum internal cross-sectional area of ​​the hose 82 selected. FIG. 9 illustrates various hoses 82A-82E having different internal cross-sectional areas perpendicular to their lengths, each of which may be selectively used to connect the chemical pump assembly 12 to the dressing 14. The size of the hose 82 used may determine the flow of oxygen, and therefore the amount of oxygen in the enclosed space. Thus, one of these hoses 82A-82E may be selectively selected by a user to provide a predetermined amount of oxygen in the enclosed space below the dressing 14. The larger the internal cross-sectional area of ​​the hose used, the more oxygen may flow therethrough and be consumed by the chemical pump 36. This is because the larger the internal cross-sectional area of ​​the hose, the more oxygen can flow from the enclosed space below the dressing 14 to the chemical pump 36 within the chemical pump assembly 12, and the less oxygen can remain in the enclosed space below the dressing 14. Thus, the ability to choose to use different sized hoses 82A-82E allows the user to selectively vary the amount of oxygen around the wound in the skin S.

[0036] Hoses 82A-82E of various sizes may be connected directly to hose fitting 76 and dressing fitting 84, or may be connected thereto via one or more adapters 86A-86D, shown in FIG. 10, having a channel extending therethrough from tip 90 to base 88. For example, the largest hose 82A may have the same internal cross-sectional area as passageway 78 and opening 85 and thus may be connected thereto directly (as described above) without the use of one of adapters 86A-86C. However, smaller hoses 82B-82E may have internal cross-sectional areas smaller than those of hose fitting 76 and dressing fitting 84 and thus may be connected to each of them via adapters 86A-86D (i.e., in a manner other than that described above). Here, one of the adapters 86A-86D is connected to each of the hose fittings 76 and the dressing fittings 84 by fitting the base 88 of one adapter over the hose fitting 76, fitting the base 88 of another adapter over the dressing fitting 84, and fitting the ends of the corresponding hoses 82B-82E around, inside, or abutting the tip 90 of each adapter. For example, hose 82B may be connected to each of the hose fittings 76 and the dressing fitting 84 via two adapters 86A, hose 82C may be connected to each of the hose fittings 76 and the dressing fitting 84 via two adapters 86B, hose 82D may be connected to each of the hose fittings 76 and the dressing fitting 84 via two adapters 86C, and hose 82E may be connected to each of the hose fittings 76 and the dressing fitting 84 via two adapters 86D. Thus, adapters 86A-86D may allow different size hoses 82A-82E to be connected to standard size hose fittings 76 and dressing fittings 84, which may themselves have a constant internal cross-sectional area.

[0037] As will be appreciated, the smaller the internal cross-sectional area of ​​the hose 82 used to connect the hose fitting 76 to the dressing fitting 84, the less oxygen that can flow from the enclosed space to the chemical pump 36 and the more oxygen that can remain in the enclosed space. Thus, by using different sized hoses 82A-82E, a user may be able to selectively choose the amount of oxygen that remains in the enclosed space.

[0038] In addition to or as an alternative to selecting the cross-sectional area of ​​the hose 82 to control the amount of oxygen within the enclosed space, a user may selectively vary the length of the hose 82 being used. FIG. 11 illustrates a hose 82 having a length and including various markings 130 along its length from a first end 132 to an opposite second end 134. These markings 130 may indicate locations where the hose 82 may be selectively disconnected (e.g., cut) to shorten it from its original length. By cutting the hose at one of the markings 130, the hose 82 may be made to various predetermined lengths. In combination with other variables, such as the minimum internal cross-sectional area of ​​the hose 82, these various predetermined lengths may correspond to predetermined levels of oxygen to be achieved within the enclosed space, which may be determined through testing. As the length of the hose 82 is selectively shortened from its original length, oxygen flow through the hose 82 from the enclosed space to the interior chamber 22 may increase, and therefore the amount of oxygen remaining within the enclosed space may correspondingly decrease. Markings 130 may be placed on hose 82 to indicate a predetermined amount (e.g., a percentage amount) by which oxygen flow through hose 82 may be increased over the original length of hose 82. These markings 130 may be included on any of hoses 82a-82e. These markings 130 may allow a user to select a desired amount of oxygen that corresponds to a predetermined amount of oxygen present in an enclosed space in addition to the cross-sectional area of ​​the hose.

[0039] The flow of oxygen through a large hose (e.g., hose 82A) or a short hose (e.g., a hose having a single segment length 136 from first end 132 to the nearest marking 130 or shorter) may comprise primarily bulk flow of oxygen, while the flow of oxygen through a small hose (e.g., hose 82E) or a long hose (e.g., a hose having its original length) may comprise primarily diffusion of oxygen, generally less than bulk flow of oxygen. Hoses between these sizes (e.g., hoses 82B-82D and hoses having lengths longer than single segment length 136) may have flows that include gradient amounts of bulk flow and diffusion, which correspond to their relative internal cross-sectional areas and lengths and can be selected by the user.

[0040] Clamps may be used to selectively prevent the flow of oxygen through hose 82. Figures 12 and 13 show two clamps 138, 140 that may be used to seal hose 82 and prevent the flow of oxygen therethrough. Clamps are not limited to those shown in Figures 12 and 13, as other clamps or mechanisms may be used to seal hose 82.

[0041] The hose 82 may be clamped when it is necessary to disconnect the hose 82 from the old chemical pump assembly 12 or the old dressing 14, when replacing the old chemical pump assembly 12 with a new one, when replacing the old dressing 14 with a new one, or when a desired amount of oxygen is achieved within the enclosed space. The clamps 138, 140 may thus be used to seal the environment within the enclosed space, and may be used to seal the environment within the internal chamber 22. After removing the old chemical pump 12 from the hose 82, it may be replaced with a new chemical pump 12, which may then be fluidly connected to the enclosed space by releasing the hose 82 from the clamp. After removing the old dressing 14 from the hose 82, it may be replaced with a new dressing 14, which may then be fluidly connected to the internal chamber 22 by releasing the hose 82 from the clamp.

[0042] The clamp 138 may include a first portion 142 and a second portion 144 rotatably connected by a hinge 146, between which the hose 82 may be disposed. The first portion 142 and the second portion 144 may be coupled to clamp the hose 82 therebetween to stop the flow of oxygen through the hose 82. The second portion 144 may include a flange 110 having a barb 112 that engages with a tip 114 of the first portion 142, thereby locking the clamp 138 around the hose 82 to stop the flow of oxygen through the hose 82. The hose 82 may be released from the clamp 138 by pressing the flange 110 so that the barb 112 no longer engages the tip 114.

[0043] The clamp 140 may include channels 116 that converge toward a base 118 toward the first end 120 of the clamp 140 and through which pins (not shown) extending from either side of the roller 122 are guided when the roller 122 is moved relative to the base 118. The hose 82 may be disposed between the roller 122 and the base 118. When the roller 122 is at the second end 124 of the clamp 140, the roller 122 does not pinch the hose 82 and the flow of oxygen therethrough is not reduced. However, if the roller 122 is moved toward the first end 120 of the clamp 140, the roller 122 may pinch the hose 82 and impede the flow of oxygen therethrough.

[0044] 14 shows a porous solid 126 disposed within the hose 82. The porous solid 126 may be a material that restricts the bulk flow of oxygen through the hose 82. The porous solid 126 may be included when it is desired that the flow of oxygen include more diffusion of oxygen than would be present without the porous solid 126. The porous solid 126 is shown schematically as including pores 128. However, such pores 128 may or may not be visible to the naked eye. Some or all of the pores 128 may be sized to only allow diffusion of oxygen through the porous solid 126, while some or all of the pores 128 may be sized to allow bulk flow of oxygen through the porous solid 126.

[0045] In addition to or as an alternative to selecting the cross-sectional area of ​​the hose 82 and selectively varying the length of the hose 82 used to control the amount of oxygen in the enclosed space, a user may cover the dressing 14, or a portion thereof, with a cover layer 15 (FIG. 7). The cover layer 15 may be less permeable to air, such as oxygen and nitrogen, than a dressing 14 without the cover layer 15. In this regard, the dressing 14 may be at least partially permeable to air. The cover layer 15 may also be impermeable to air.

[0046] An impermeable cover layer 15 may seal the exposed surface of the dressing 14, thereby defining a covered portion of the dressing 14, as shown in FIG. 7. The covered portion of the dressing 14 may include the entire dressing 14 or only a portion thereof. The cover layer 15 makes the covered portion of the dressing 14 impermeable to air, and therefore impermeable to oxygen. By providing the oxygen-impermeable properties to the covered portion of the dressing 14, the cover layer 15 inhibits oxygen from entering the enclosed space from the surrounding environment.

[0047] As will be appreciated, the greater the area of ​​the cover layer 15 relative to the area of ​​the dressing 14, the more oxygen is inhibited from infiltrating through the dressing 14. In other words, a relatively large cover layer 15 covers more of the area of ​​the dressing 14 and therefore inhibits oxygen from infiltrating through the dressing 14 into the enclosed space than a relatively small cover layer 15. Thus, the larger the cover layer 15, the less oxygen will infiltrate through the dressing 14, while the smaller the cover layer 15, the more oxygen will infiltrate through the dressing 14. In FIG. 7 , various dotted lines are shown on the cover layer 15 to indicate various sizes for the cover layer 15, or predetermined cut lines are shown for selectively changing the original size of the cover layer 15 so that it can be made smaller than its original size to allow a desired amount of oxygen to infiltrate the enclosed space.

[0048] Restricting the permeability of air through the covered portion of the dressing 14 limits the amount of oxygen entering the enclosed space. In combination with the flow of oxygen from the enclosed space through the hose 82 into the inner chamber 22 and consumed by the chemical pump 36 (reactor), this restriction reduces the amount of oxygen within the enclosed space and surrounding the tissue site. Thus, because the cover layer 15 is impermeable to oxygen, it creates a lower level of oxygen within the enclosed space than would be possible if the cover layer 15 were not used. In this manner, the cover layer 15 provides the user with another level of control to regulate the amount of oxygen surrounding the tissue site.

[0049] The cover layer 15 may have a size (i.e., area) that is selectable by the user to provide a specific amount of oxygen around the tissue site. This size may be a predetermined size corresponding to a predetermined amount of oxygen within the enclosed space and around the tissue site. The cover layer 15 having a predetermined size may be selected from a plurality of cover layers having different predetermined sizes, or may be selected by selectively altering the original size of the cover layer 15, such as by cutting the cover layer 15 smaller.

[0050] For this purpose, the cover layer 15 may comprise a variety of materials, including a base polymer film coated or filled with a material that reduces its through-thickness air permeability. These coatings or filling materials may include blocking materials such as metals, graphene, polyvinylidene chloride, polyvinyl alcohol, ethylene vinyl alcohol, or combinations thereof. The base polymer film coated or filled with these blocking materials may include high-density polyethylene, polyethylene terephthalate, polylactic acid, polypropylene, polystyrene, or the like, or combinations thereof. The cover layer 15 may also include additional layers to form a multilayer structure, which may include these blocking materials. The cover layer 15 may also be a metallized polymer film similar to those described herein for the thin film 62.

[0051] The cover layer 15 may include a sealant to adhere the cover layer 15 to the exposed surface of the dressing 14. The sealant may be disposed on the bottom surface of the cover layer 15. The sealant may include an adhesive, a hydrogel material, a silicone material (e.g., silicone gel), or any other material capable of inhibiting air movement. The sealant may be permeable to air, like the other materials of the cover layer 15. The sealant may also be resealable, sealing the cover layer 15 to the dressing 14 and subsequently allowing the cover layer 15 to be removed from the dressing 14.

[0052] The amount of oxygen present in the enclosed space depends on the balance between the amount of oxygen conducted from the enclosed space through the fluid passageway to the internal chamber 22 and the amount of oxygen delivered from the ambient environment through the dressing 14 to the enclosed space. Therefore, selecting the length and minimum internal cross-sectional area of ​​the fluid passageway, along with selecting the area of ​​the dressing 14 covered by the cover layer 15, will determine the amount of oxygen present in the enclosed space. If relatively more oxygen is desired in the enclosed space, the length of the fluid passageway may be selected to be longer, the minimum internal cross-sectional area of ​​the fluid passageway may be selected to be smaller, and / or a smaller area of ​​the dressing 14 may be covered by the cover layer 15, or the dressing 14 may not be covered by the cover layer 15. If less oxygen is desired in the enclosed space, the length of the fluid passageway may be selected to be shorter, the minimum internal cross-sectional area of ​​the fluid passageway may be selected to be larger, and / or a larger area of ​​the dressing 14 may be covered by the cover layer 15.

[0053] It will be appreciated that the various above-disclosed embodiments, other features and functions, or alternatives or variations thereof, may be desirably combined into many other different systems or applications, and various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be made by those skilled in the art thereafter, and are intended to be encompassed by the following claims.

Claims

1. 1. A system for controlling the amount of oxygen in an enclosed space, comprising: a dressing configured to seal tissue to define the enclosed space between the dressing and the tissue; a housing defining an internal chamber and including a reactor disposed within the internal chamber; a fluid passageway connecting the internal chamber and the enclosed space and allowing oxygen to flow between the internal chamber and the enclosed space; the reactor is configured to chemically react with oxygen in the inner chamber; the system includes a plurality of hoses having different lengths at least partially defining the fluid passageway, the plurality of hoses having different lengths being selectable by a user to control the amount of oxygen in the enclosed space, the plurality of hoses having different lengths, different cross-sectional areas, or a combination thereof, of the fluid passageway corresponding to predetermined levels of oxygen to be achieved in the enclosed space; system.

2. A system for controlling the amount of oxygen in an enclosed space, comprising: a dressing configured to seal tissue to define the enclosed space between the dressing and the tissue; a housing defining an internal chamber and including a reactor disposed within the internal chamber; a fluid passageway connecting the internal chamber and the enclosed space and allowing oxygen to flow between the internal chamber and the enclosed space; the reactor is configured to chemically react with oxygen in the inner chamber; the system includes a hose that can be selected by a user to control the amount of oxygen in the enclosed space, the hose having a plurality of different predetermined lengths, a plurality of different predetermined cross-sectional areas, or a combination thereof, of the fluid passageway corresponding to a predetermined level of oxygen to be achieved in the enclosed space, and that can change the length of the fluid passageway from an original length to a changed length. system.

3. 3. The system of claim 2, wherein the hose includes markings along the length of the hose indicating the amount of oxygen required within the enclosed space.

4. A system for controlling the amount of oxygen in an enclosed space, comprising: a dressing configured to seal tissue to define the enclosed space between the dressing and the tissue; a housing defining an internal chamber and including a reactor disposed within the internal chamber; a fluid passageway connecting the internal chamber and the enclosed space and allowing oxygen to flow between the internal chamber and the enclosed space; the reactor is configured to chemically react with oxygen in the inner chamber; the system including a plurality of hoses having different cross-sectional areas at least partially defining the fluid passageway, the plurality of different predetermined lengths, the plurality of different predetermined cross-sectional areas, or a combination thereof, of the fluid passageway being selectable by a user to control the amount of oxygen in the enclosed space, the different lengths, the different cross-sectional areas corresponding to predetermined levels of oxygen to be achieved in the enclosed space; system.

5. The system of claim 4 , wherein the system includes a plurality of adapters, each of the plurality of adapters configured to connect one of the hoses to the housing and the dressing.

6. A system for controlling the amount of oxygen in an enclosed space, comprising: a dressing configured to seal tissue to define the enclosed space between the dressing and the tissue; a housing defining an internal chamber and including a reactor disposed within the internal chamber; a fluid passageway connecting the internal chamber and the enclosed space and allowing oxygen to flow between the internal chamber and the enclosed space; the reactor is configured to chemically react with oxygen in the inner chamber; the system includes a plurality of different predetermined lengths, a plurality of different predetermined cross-sectional areas, or a combination thereof, of the fluid passageway selectable by a user to control the amount of oxygen in the enclosed space, the different lengths, the different cross-sectional areas corresponding to predetermined levels of oxygen to be achieved in the enclosed space; a hose connected to the housing and the dressing member and at least partially defining the fluid passageway; and a clamp fastened to the hose to vary the cross-sectional area of ​​the hose to select the cross-sectional area of ​​the fluid passageway. system.

7. A system for controlling the amount of oxygen in an enclosed space, comprising: a dressing configured to seal tissue to define the enclosed space between the dressing and the tissue; a housing defining an internal chamber and including a reactor disposed within the internal chamber; a fluid passageway connecting the internal chamber and the enclosed space and allowing oxygen to flow between the internal chamber and the enclosed space; the reactor is configured to chemically react with oxygen in the inner chamber; the system comprising a plurality of different predetermined lengths, a plurality of different predetermined cross-sectional areas, or a combination thereof, of the fluid passageway selectable by a user to control the amount of oxygen in the enclosed space, the different lengths, a plurality of different predetermined cross-sectional areas corresponding to predetermined levels of oxygen to be achieved in the enclosed space; a porous solid body is disposed in the fluid passage to select a cross-sectional area of ​​the fluid passage; system.

8. the housing includes a hose coupling, and the dressing includes a dressing coupling; the hose coupling is configured to attach the hose to the housing, and the dressing coupling is configured to attach the hose to the dressing, such that the hose at least partially defines the fluid passageway. The system of claim 1 .

9. The system of claim 8 , wherein the hose fitting and the dressing fitting are each barbed fittings.

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