Negative Pressure Therapy, including mechanical and chemical pumps

Abstract

The negative pressure assembly includes a drape, a sealing element, a reactor, a valve, and a mechanical pump assembly. The drape and sealing element cooperate to define an enclosed space when applied to the skin. The reactor is positioned to be in fluid communication with the enclosed space when the drape is covering the treatment site. The reactor reacts with a selected gas in the air and consumes the selected gas. The valve has a first operating state in which gas is drawn from the enclosed space through the valve. The mechanical pump assembly includes a pump chamber fluidly connectable to the enclosed space through the valve when the valve is in the first operating state. The mechanical pump assembly is configured to be in fluid communication with the enclosed space and to draw air from the enclosed space into the pump chamber.

Description

[Technical field]

[0001] Negative pressure therapy is a treatment that utilizes negative pressure to treat and restore the skin. Negative pressure is a term that describes pressure that is lower than normal atmospheric pressure. Negative pressure therapy is used on several areas of the skin, including wounds and cuts. Additionally, negative pressure therapy is useful in managing wounds with complex healing concerns. Additionally, negative pressure therapy may also be used for cosmetic purposes, such as wrinkle removal. [Background technology]

[0002] Negative pressure therapy is generally achieved by maintaining a reduced pressure under the dressing over the treatment site. A vacuum source, such as a pump, applies a reduced pressure inside the dressing over the treatment site. However, when a chemically-activated vacuum source is first activated, the desired negative pressure may not be achieved for several minutes after activation of the vacuum source. As a result, if the dressing is not properly sealed at the beginning of negative pressure therapy, indications that the dressing is not sealed may not be noticeable for several minutes. Furthermore, when reduced pressure is eventually achieved, it may be easy for the negative pressure to fall below the target pressure range for negative pressure therapy (e.g., too much vacuum is applied to the skin). If the negative pressure falls below the target pressure range, the dressing may become uncomfortable for the patient. Summary of the Invention

[0003] In view of the above, the negative pressure assembly includes a drape, a sealing element, a reactor, and a mechanical pump assembly. The drape covers a treatment site on a patient and is capable of maintaining a negative pressure beneath the drape when a reduced pressure is applied and sealed against the skin. The sealing element cooperates with the drape when applied to the skin to define an enclosed space covered by the drape and surrounded by the sealing element. The reactor is configured to react with and consume a selected gas in air and is positioned relative to the drape and the sealing element such that the reactor is in fluid communication with the enclosed space when the drape covers the treatment site. The mechanical pump assembly is fluidly connectable with the enclosed space and has a pump chamber in fluid communication with the enclosed space to draw air from the enclosed space into the pump chamber.

[0004] The negative pressure assembly described above may further include a dressing including a drape and an absorbent material. Additionally, the reactor may be disposed within the dressing. Additionally, a relief valve may be disposed on the dressing. The relief valve is in fluid communication with the enclosed space and the surroundings. The relief valve allows gas from the surroundings to enter the enclosed space when the pressure difference between the surroundings and the enclosed space is outside a predetermined pressure range.

[0005] The mechanical pump assembly can be connected to the dressing member, with the pump chamber of the mechanical pump assembly in fluid communication with the enclosed space. The mechanical pump assembly can be connected to the dressing member via a valve, a fitting, or a hose. The valve can be configured to allow gas to exit through the valve to the pump chamber of the mechanical pump assembly while preventing ambient air from entering the enclosed space through the valve. Or, the valve can be a two-way valve configured to allow gas to exit through the valve when the ambient pressure is lower than the enclosed space pressure, and allow gas from the ambient to enter the enclosed space through the valve when the pressure difference between the ambient and the enclosed space is outside a predetermined pressure range. Furthermore, the mechanical pump assembly can include a manually actuated actuator and a biasing mechanism operatively connected to the movable pump element. When the manually actuated actuator is actuated, the biasing mechanism moves the movable pump element. As a result, air is drawn into the mechanical pump assembly. The biasing mechanism can be a spring, and the movable pump element can be a piston.

[0006] The negative pressure assembly described above may further include a chemical pump assembly including a chemical pump housing having a chamber. In this embodiment, the reactor is disposed within the chamber of the chemical pump housing instead of the dressing. Additionally, the chemical pump assembly may include a diaphragm that moves toward the chamber to indicate when the chamber is under negative pressure. Additionally, the relief valve may alternatively be disposed on the chemical pump assembly instead of the dressing or may remain on the dressing.

[0007] The chemical pump housing may be connected to the dressing via a valve, a fitting, or a hose. Furthermore, the chemical pump assembly may be connected to a second dressing covering a second dressing site via a second valve, a second fitting, or a hose. The hose may be Y-shaped to simultaneously connect the chemical pump assembly to the dressing and the second dressing. When the chemical pump housing is connected to the dressing, the chamber of the chemical pump assembly is in fluid communication with the enclosed space. The hose may be retractable within the chemical pump assembly. Alternatively, the hose may be wrapped around a wrap element provided on the chemical pump assembly. Also, if the dressing has only one fitting, the chemical pump assembly may be disconnected from the fitting and the mechanical pump assembly may be connected to the fitting. Alternatively, the chemical pump assembly and the mechanical pump assembly may be connected to the dressing via separate valves, fittings, and / or hoses.

[0008] In yet another embodiment, a mechanical pump assembly may be connected to a chemical pump assembly such that a pump chamber of the mechanical pump assembly is in fluid communication with the enclosed space via the chemical pump assembly. The mechanical pump assembly may be connectable to the chemical pump housing via a valve, fitting, or hose. In an embodiment having a valve, gas can exit the pump chamber through the valve while simultaneously preventing ambient air from entering the chamber through the valve.

[0009] A negative pressure assembly according to another embodiment includes a drape, a sealing element, a valve, and a mechanical pump assembly. The drape covers a treatment site on a patient and is capable of maintaining a negative pressure beneath the drape when a reduced pressure is applied and sealed against the patient's skin. The sealing element cooperates with the drape when applied to the skin to define an enclosed space surrounded by the drape and surrounded by the sealing element. The valve is disposed on the drape and has a first operational state in which gas exits the enclosed space through the valve and a second operational state in which gas is prevented from exiting the enclosed space through the valve. The mechanical pump assembly includes a pump chamber fluidly connectable to the enclosed space via the valve when the valve is in the first operational state. The mechanical pump assembly is also configured to draw air from the enclosed space into the pump chamber when in fluid communication with the enclosed space.

[0010] The negative pressure assembly may further include a dressing including a drape, a sealing element, and an absorbent material. The mechanical pump assembly is connectable to the dressing via a valve such that the pump chamber is in fluid communication with the enclosed space. The negative pressure assembly may include a reactor disposed relative to the drape and the sealing element such that the reactor is in fluid communication with the enclosed space when the drape is over the dressing site. The reactor reacts with a selected gas in the air and consumes the selected gas. In one embodiment, the reactor is disposed within the dressing. In another embodiment, the negative pressure assembly further includes a chemical pump assembly having a chemical pump with a reactor disposed therein.

[0011] Additionally, the dressing may be provided with a relief valve. The relief valve is in fluid communication with the enclosed space and the surroundings. The relief valve allows gas from the surroundings to pass through the relief valve into the enclosed space when the pressure difference between the surroundings and the enclosed space is outside of a predetermined pressure range. Alternatively, the valve may be a two-way valve that allows gas to pass through the valve when the pressure of the surroundings is lower than the pressure of the enclosed space, and allows gas from the surroundings to pass through the valve into the enclosed space when the pressure difference between the surroundings and the enclosed space is outside of a predetermined pressure range. The predetermined pressure range may be 50-200 mmHg lower than atmospheric pressure.

[0012] Additionally, the mechanical pump assembly may include a manually actuated actuator and a biasing mechanism operably connected to the movable pump element. Actuation of the manually actuated actuator causes the biasing mechanism to move the movable pump element, thereby drawing air into the mechanical pump assembly. The biasing mechanism may be a spring and the movable pump element may be a piston. The hose may be retractable within the mechanical pump assembly, or the hose may be wrapped around a wrap element of the mechanical pump assembly. The mechanical pump assembly may further be connected to a second dressing member covering a second dressing site via a valve, fitting, or hose.

[0013] A negative pressure assembly according to another embodiment includes a drape that covers a treatment site on a patient and is capable of maintaining a negative pressure beneath the drape when reduced pressure is applied and sealed against the skin, and a sealing element that cooperates with the drape when applied to the skin to define an enclosed space covered by the drape and surrounded by the sealing element. The negative pressure assembly also includes a reactor disposed relative to the drape and the sealing element such that the reactor is in fluid communication with the enclosed space when the drape covers the treatment site. The reactor is configured to react with a selected gas in the air and consume the selected gas. The negative pressure assembly also includes a valve including at least one movable element. The valve has a first operating state in which gas is drawn from the enclosed space through the valve. The negative pressure assembly also includes a mechanical pump assembly including a pump chamber fluidly connectable with the enclosed space via the valve when the valve is in the first operating state. The mechanical pump assembly is configured to be fluidly connected with the enclosed space and to draw air from the enclosed space into the pump chamber of the mechanical pump assembly. [Brief description of the drawings]

[0014] [Figure 1] Figure 1 is a perspective view of a negative pressure kit. [Diagram 2] FIG. 2 is a schematic cross-sectional view of a dressing member and mechanical pump assembly of a negative pressure kit according to one embodiment. [Diagram 3] FIG. 3 is a perspective view of the dressing member and mechanical pump assembly. [Figure 4] 4 is a perspective view of the dressing and chemical pump assembly of FIG. 3 prior to connection of the chemical pump assembly to the dressing; [Diagram 5] FIG. 5 is a schematic cross-sectional view of a chemical pump assembly according to one embodiment. [Figure 5A] FIG. 5A is a schematic cross-sectional view of a chemical pump assembly according to yet another embodiment. [Figure 6] FIG. 6 is a schematic cross-sectional view of a mechanical pump assembly prior to actuation. [Figure 7] FIG. 7 is a schematic cross-sectional view of the mechanical pump assembly after actuation. [Figure 8] FIG. 8 is a perspective view of the dressing and chemical pump assembly after the chemical pump assembly has been connected to the dressing and before negative pressure is created in the treatment area beneath the dressing. [Figure 9] FIG. 9 is a perspective view of the dressing, the chemical pump assembly, and the mechanical pump assembly (schematic cross-sectional view) after the chemical pump assembly has been connected to the dressing and the mechanical pump assembly has been connected to the chemical pump assembly, but prior to actuation of the mechanical pump assembly. [Figure 10] FIG. 10 is a perspective view of the dressing, the chemical pump assembly, and the mechanical pump assembly after the chemical pump assembly has been connected to the dressing and the mechanical pump assembly has been connected to the chemical pump assembly, and after the mechanical pump assembly has been activated. [Figure 11] FIG. 11 is a perspective view of the dressing and chemical pump assembly after the chemical pump assembly has been connected to the dressing and a negative pressure in the therapeutic range has been reached beneath the dressing, causing the diaphragm to invert toward the chamber within the chemical pump assembly. [Figure 12] FIG. 12 is a perspective view of the dressing, the chemical pump assembly, and the mechanical pump assembly before the chemical pump assembly is connected to the dressing and after the mechanical pump assembly is connected to the dressing and before actuation of the mechanical pump assembly. [Figure 13] FIG. 13 is a schematic cross-sectional view of a portion of a chemical pump housing including a wrap element. [Figure 14] FIG. 14 is a perspective view of the chemical pump assembly, the dressing, and a second dressing after negative pressure has been achieved in the treatment area beneath the dressing, according to another embodiment. [Figure 15] FIG. 15 is a perspective view of a mechanical pump assembly (schematic cross-sectional view) and a dressing after connection of the mechanical pump assembly to the dressing and prior to actuation of the mechanical pump assembly, according to yet another embodiment. [Figure 16] FIG. 16 is a perspective view of a mechanical pump assembly. [Figure 17] 17 is an exploded perspective view of the mechanical pump assembly of FIG. 16; FIG. [Figure 18] FIG. 18 is a perspective view of a chemical pump assembly. [Figure 19] 19 is a front cross-sectional view of the chemical pump assembly of FIG. 18. [Figure 20] 20 is a perspective view of the chemical pump assembly and two dressing members of FIG. 18; [Figure 21] FIG. 21 is a schematic cross-sectional view of a mechanical pump assembly and a chemical pump assembly prior to actuation of the mechanical pump assembly, according to one embodiment. [Figure 22] FIG. 22 is a schematic cross-sectional view of a mechanical pump assembly and a chemical pump assembly prior to actuation of the mechanical pump assembly, according to one embodiment. [Figure 23] FIG. 23 is a cross-sectional view of the treatment member. [Figure 24] FIG. 24 is a cross-sectional view of the dressing member connected to the mechanical pump assembly after the mechanical pump assembly has been activated. [Diagram 25] FIG. 25 is a front cross-sectional view of a chemical pump assembly having a mechanical pump assembly disposed in an inner chamber of a chemical pump housing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] A negative pressure kit 10 useful for negative pressure therapy is shown in Figure 1. Negative pressure as described herein is a pressure below atmospheric pressure. The negative pressure kit 10 includes a tray kit 12 and a negative pressure assembly. In the embodiment shown in Figure 1, the negative pressure assembly includes at least one dressing member 14, a chemical pump assembly 16, and a mechanical pump assembly 18.

[0016] The tray kit 12 includes a top cover 20 and a bottom cover 22. At least one recess 24 may be provided in the bottom cover 22 for storing at least one dressing member 14, the chemical pump assembly 16, and the mechanical pump assembly 18. A spacer wall 26 may be added to maintain a space between the top cover 20 and the bottom cover 22 when the tray kit 12 is closed. The spacer wall 26 may at least partially surround the periphery of the at least one recess 24. The bottom cover 22 may further include a fastening element for fastening a component in the at least one recess 24. The tray kit 12 may also include a closing element for maintaining the top cover 20 and the bottom cover 22 in a closed state, and may further include a locking attachment for locking the tray kit 12 when the tray kit 12 is closed.

[0017] With reference to FIG. 2, the dressing 14 is placed on a patient's skin at a treatment site 28. The treatment site 28 may be, but is not limited to, a wound, a cut, or skin that is free of a wound or cut. In the illustrated embodiment, the dressing 14 includes a drape 40, a wicking or absorbent element 42, and a fitting 44. The dressing 14 may include additional components, such as a sealing element 46, and may be of similar construction to the dressings described in U.S. Patent Application No. 16 / 114,813 and / or International Application No. PCT / US2016 / 059364. The drape 40 may be made of a flexible material, or may be made of a thin flexible elastomeric film. Examples of such materials include polyurethane or polyethylene film. The drape 40 may include at least one opening 48 (see FIG. 1) that can cooperate with the fitting 44. The drape 40 in the illustrated embodiment is a thin film that can maintain a negative pressure underneath the drape 40 when depressurized and sealed against the patient's skin when the opening 48 is not in communication with the environment.

[0018] The drape 40 further includes a drape top 52 and a drape edge 54. The drape top 52 and the drape edge 54 may be made of one continuous piece or multiple fused pieces. The drape edge 54 is disposed around the treatment area 28 and the drape top 52 covers the treatment area 28. The drape 40 may be made in a variety of shapes and sizes to cover a variety of treatment areas 28. An opening 48 extends through the drape top 52.

[0019] 2, the sealing element 46 cooperates with the drape 40 and the skin S to form an enclosed space 60 defined between the drape 40 and the dressing site 28 and surrounded by the sealing element 46. The sealing element 46 may be separate from the dressing 14 or may be a component of the dressing 14. The sealing element 46 acts like a gasket because it prevents fluids (including gases) between the drape 40 and the skin S from escaping. When properly sealed, air or selected gases can selectively exit the dressing 14 through at least one opening 48 and fitting 44. Thus, the sealing element 46 helps maintain a negative pressure within the dressing 14. The sealing element 46 may be made from a material such as silicone or a hydrogel material.

[0020] The dressing member 14 may further include a wound contact layer 68. The drape top 52 covers the wound contact layer 68 and / or the wicking or absorbent element 42. The wound contact layer 68 may be made of an elastomeric material, such as a polymeric material having rubber-like properties. Additionally, the wound contact layer 68 may be an elastomeric material that is a thin, flexible elastomeric film. Some examples of such materials include silver coated nylon, perforated silicone mesh, or other materials that do not adhere to the patient's tissue. The wound contact layer 68 contacts the dressing area 28. The wound contact layer 68 may include at least one opening that cooperates with the absorbent element 42, allowing exudate to continue to move from the dressing area 28 into the enclosed space 60. The sealing element 46 may also be provided on the side of the wound contact layer 68 (or the absorbent element 42 if the wound contact layer 68 is not included) that contacts the dressing area 28.

[0021] A drape release liner (not shown) is provided on the underside of drape edge 54. The drape release liner is removed before dressing 14 is applied to treatment site 28. When the drape release liner is removed, adhesive 66 on the underside of drape edge 54 is exposed. When dressing 14 is placed on the patient, adhesive 66, which may be an acrylic adhesive different from sealing element 46, secures drape edge 54 to the patient's skin S about treatment site 28. Thus, contact between drape edge 54 and skin S is maintained.

[0022] The wicking or absorbent element 42 is made of an absorbent material capable of absorbing exudate from the treatment site 28. The absorbent element 42 may be made of superabsorbent polymers, absorbent beads, foams, or natural absorbents. The absorbent element 42 may also have an appropriate void for airborne gases so that reduced pressure can be maintained. For example, the absorbent element 42 may be made of a foam that is relatively rigid compared to the drape 40 so that a void for gases is maintained while absorbing exudate from the wound. The absorbent element 42 may also be made of the superabsorbent polymers mentioned above that expand, for example, between adjacent beads to form a void for gases, to provide the volume control mentioned above. The absorbent element 42 may be a hydroactive wound pad available under the trademark "Vilmed" (USA Registered Trademark) that chemically absorbs exudate and, unlike a sponge, prevents the exudate from passing through the wicking element toward the vacuum source.

[0023] The dressing 14 may include a breathable, liquid-impermeable membrane 70 that covers the opening 48 of the drape top 52. In an embodiment, the breathable, liquid-impermeable membrane 70 is disposed on the underside of the drape top 52. Gas can pass through the breathable, liquid-impermeable membrane 70, but liquid cannot pass through the breathable, liquid-impermeable membrane 70. Thus, exudates cannot flow through the breathable, liquid-impermeable membrane 70. In another embodiment, the breathable, liquid-impermeable membrane 70 is disposed on the upper side of the drape top 52. Additionally, FIG. 2 shows a chemical pump 82 in the form of a reactor located within the dressing 14 beneath the drape 40. The chemical pump 82 may be located in other locations, as will be described in more detail below.

[0024] 3 shows the dressing 14 connected to the mechanical pump assembly 18 via a hose 62 (shown diagrammatically). When the mechanical pump assembly 18 is connected to the dressing 14, the mechanical pump assembly 18 is in fluid communication with the enclosed space 60 via the fitting 44 in a manner described in more detail below. Actuation of the mechanical pump assembly 18 draws gas from the enclosed space 60 into the mechanical pump assembly 18 through the opening 48, the fitting 44, and the hose 62. In this manner, the seal of the dressing 14 against the skin S may be checked in that the drape 40 is drawn towards the skin S. The hose 62 may then be removed from the fitting 44, allowing air to enter the enclosed space 60 and returning the pressure within the enclosed space 60 to atmospheric pressure.

[0025] 4 shows the dressing 14 and the chemical pump assembly 16. The chemical pump assembly 16 includes a chemical pump housing 80, a chemical pump 82 (shown in phantom in FIG. 4) disposed within a chamber 84 (see FIG. 5), and a bottom opening 86 at the bottom of the chemical pump housing 80 in fluid communication with the chamber 84. When connected to the fitting 44, the chamber 84 within the chemical pump housing 80 is in fluid communication with the enclosed space 60 via the bottom opening 86, the at least one opening 48, and the fitting 44 on the drape 40. The chemical pump assembly 16 creates a reduced pressure inside the dressing 14 in a manner described in more detail below.

[0026] The chemical pump 82 of the chemical pump assembly 16 is a reactor configured to react with a selected gas in the air. The chemical pump 82 is positioned relative to the drape 40 and the sealing element 46 such that the chemical pump 82 is in fluid communication with the enclosed space 60. The chemical pump 82 consumes the selected gas from the enclosed space 60, thereby removing the gas and reducing the gas pressure. In this manner, the chemical pump 82 removes the gas from the air, thereby reducing the gas pressure in the enclosed space 60, even though it does not include an inlet and an outlet to move fluid from one place to another as in a conventional pump. Examples of reactors that can be used in the chemical pump assembly 16 are described in U.S. Patent Application Publication No. 2014 / 0109890 and / or International Application No. PCT / US2016 / 059364. The chemical pump 82 may be activated by exposing the chemical pump 82 to the environment, sealing the chemical pump 82 until it is ready to be activated. Alternatively, the electrolyte solution may be provided in a rupturable package, such as that found in the impregnated pad of U.S. Patent Application Publication No. 2014 / 0109890, which is subsequently ruptured to react with the reducing agent on the substrate. For therapeutic negative pressure systems utilized in wound treatment, the reported operating pressure range is -50 mmHg to -200 mmHg (560 to 710 mmHg absolute) relative to a standard atmospheric pressure of 760 mmHg. If the pressure is less than 560 mmHg, the at least one dressing member 14 may be uncomfortable for the patient. If the pressure is greater than 710 mmHg, the negative pressure treatment may be less effective compared to pressures below 710 mmHg. However, a smaller target pressure range may be desired within the range of 560 to 710 mmHg. Thus, the reactor 82 may be configured to maintain the reduced pressure within a predetermined target pressure range.

[0027] The chemical pump assembly 16 is configured to maintain a predetermined chamber volume when the chemical pump 82 consumes a selected gas from the enclosed space 60. The size of the reactor 82 depends on the volumes of the chamber 84, the hose 62, and the enclosed space 60, among other factors. In another embodiment, as shown in FIG. 2, the reactor 82 may be provided in the dressing 14 in place of the chemical pump assembly 16. As a result, in a method of applying negative pressure within the dressing 14, the chemical pump assembly 16 may be eliminated.

[0028] In the embodiment shown in FIG. 5, a top opening 90 with a first valve 92 is provided on the top of the chemical pump housing 80. Additionally, the top opening 90 and the first valve 92 may be provided on the side of the chemical pump housing 80 and elsewhere on the chemical pump housing 80. In another embodiment, a valve operating similarly to the first valve 92 may be provided on the dressing 14. The first valve 92 is configured to cooperate with the mechanical pump assembly 18. In a first operating state, the first valve 92 allows air to exit the chamber 84 through the first valve 92 when the mechanical pump assembly 18 is inserted into the first valve 92. In a second operating state, the first valve 92 prevents ambient air from entering the chamber 84 through the top opening 90 and the first valve 92 when the mechanical pump assembly 18 is not inserted into the first valve 92. Examples of such valves include, but are not limited to, spring-loaded check valves and valves with flaps. 5 shows a first valve 92 having a flap 94. The flap 94 of the first valve 92 is closed before the mechanical pump assembly 18 is introduced into the top opening 90. Gas will not leak through the top opening 90 and the first valve 92 unless the mechanical pump assembly 18 is introduced. The flap 94 of the first valve 92 returns to a closed position due to its elastic force when the mechanical pump assembly 18 is removed.

[0029] In the illustrated embodiment, the seal member 96 is provided on the bottom surface of the chemical pump housing 80. The seal member 96 may also be provided on the side of the chemical pump housing 80 and elsewhere on the chemical pump housing 80. In the illustrated embodiment, the seal member 96 is disposed in the lower opening 86 and configured to cooperate with the fitting 44. When the chemical pump assembly 16 is pressed into and mated with the fitting 44, the seal member 96 allows air to enter the chamber 84 through the lower opening 86. When the chemical pump assembly 16 is not mated with the fitting 44, the seal member 96 prevents ambient air from entering the chamber 84. FIG. 5 shows the seal member 96 having a flap 98. The flap 98 of the seal member 96 is closed before the chemical pump assembly 16 is mated with the fitting 44. Gas cannot enter through the seal member 96 unless the flaps 98 are moved from their initial closed position. Alternatively, the sealing member 96 may be a foil or other member that is perforated when pressed against the fitting 44 .

[0030] Referring to FIG. 4, a negative pressure indicator, which in the illustrated embodiment is a diaphragm 100, may be disposed on the chemical pump housing 80 to indicate to a user that the system is under negative pressure. Referring to FIG. 4, the diaphragm 100 may be dome-shaped and protrude from the chemical pump housing 80 when the pressure in the chamber 84 is equal to or greater than a predetermined pressure, which may be atmospheric pressure. The diaphragm 100 may be made of an elastic material. When the pressure in the chemical pump assembly 16 or the dressing 14 falls below a target pressure range, the diaphragm 100 is drawn into the chemical pump housing 80. When the diaphragm 100 is drawn toward the interior of the chemical pump housing 80, the diaphragm 100 inverts. When the diaphragm 100 inverts, this provides an indication to a user that the system is under negative pressure. Alternatively, the indicator may be provided on the dressing 14.

[0031] The mechanical pump assembly 18 is shown generally in Figures 6 and 7. In the illustrated embodiment, the mechanical pump assembly 18 is a single action vacuum source used to create a negative pressure within the enclosed volume 60 of the dressing 14. When the chemical pump assembly 16 is first attached to the dressing 14 (see Figure 8), no negative pressure is generated within the enclosed volume 60 of the dressing 14 until the chemical pump assembly 16 is fully activated, i.e., until the reactor 82 removes the selected gas in the air from the chamber 84 and the enclosed volume 60. Thus, the mechanical pump assembly 18 may also help maintain a negative pressure in the dressing 14. Additionally, the mechanical pump assembly 18 may help pull the dressing 14 toward the treatment site 28.

[0032] In one embodiment, the mechanical pump assembly 18 may include a manually actuated actuator and a biasing mechanism operably connected to the movable pump element. Actuation of the manually actuated actuator causes the biasing mechanism to move the movable pump element, drawing air into the mechanical pump assembly. As a result, negative pressure is created within the enclosed space 60. Thus, the mechanical pump assembly 18 may be a pneumatic piston cylinder. With reference to FIG. 6, the mechanical pump assembly 18 includes a mechanical pump housing 120 and a pump chamber having a first chamber 138 and a second chamber 140. An actuator 144 may be provided on a side of the mechanical pump housing 120. The actuator 144 may be manually operated and used to activate the operation of the mechanical pump assembly 18. Examples of such actuators include, but are not limited to, a button, a switch, or a trigger.

[0033] An inner wall 122 may be used to separate the first chamber 138 from the second chamber 140. The inner wall 122 includes a rod opening 142 for receiving the piston rod 130. A seal 124 surrounds the inner wall 122 to prevent any gas from passing between the first chamber 138 and the second chamber 140 around the inner wall 122. Alternatively, the inner wall 122 may be integrally formed with the mechanical pump housing 120. Additionally, a second seal 146 at the rod opening 142 may surround the piston rod 130, thereby preventing gas from passing between the first chamber 138 and the second chamber 140 through the rod opening 142 without restricting the movement of the piston rod 130.

[0034] The mechanical pump housing 120 includes a tip 134 disposed at the bottom. The tip 134 includes a tip opening 136 in fluid communication with a first chamber 138. Additionally, the mechanical pump assembly 18 may be in fluid communication with the opening 48 on the drape 40 through a hose 62 that may be connected to the tip 134 or through the tip 134 directly connected to the fitting 44. The hose 62 may be of any length, and thus a long hose 62 may be used. Thus, the mechanical pump assembly 18 may be operated on the dressing 14 before the chemical pump assembly 16 is attached to the dressing 14. This helps seal the dressing 14 at the dressing site 28. As a result, the mechanical pump assembly 18 may apply reduced pressure directly to the dressing 14.

[0035] In the illustrated embodiment, the biasing mechanism is a spring 126 and the movable element is a piston 128. The spring 126 and the piston 128 are disposed in a first chamber 138. Before the mechanical pump assembly 18 is actuated, a majority of the piston rod 130 is also disposed in the first chamber 138. Also, a head 132 disposed on the upper part of the piston rod 130 is disposed in a second chamber 140. When the mechanical pump assembly 18 is introduced into the first valve 92 of the chemical pump assembly 16 (FIG. 9) or connected to the fitting 44 by the hose 62 (FIG. 3), the actuator 144 is used to activate the operation of the mechanical pump assembly 18. When the mechanical pump assembly 18 is actuated, a connector 170 (see FIG. 6) between the actuator 144 and the piston rod 130 releases the piston rod 130, and air enters the first chamber 138 of the mechanical pump housing 120 through the tip opening 136. The connector 170 can be re-engaged with the piston rod 130. Thus, the mechanical pump assembly 18 may be reusable. As shown in FIG. 7, the spring 126 biases the piston 128 toward the inner wall 122, which draws air into the first chamber 138. The piston rod 130 moves into the second chamber 140 and the head 132 moves toward the top surface of the mechanical pump housing 120. As a result, negative pressure is created in the dressing 14.

[0036] The negative pressure assembly may reach a negative pressure lower than the target pressure range, for example, a vacuum, i.e., excessive negative pressure, may be achieved within the enclosed space 60. To maintain the target pressure range, a relief valve 148 may be provided on the chemical pump housing 80 to release pressure when necessary, as shown in FIG. 5. Alternatively, a relief valve similar in operation to the relief valve 148 may be provided on the drape 40 of the dressing 14. The relief valve 148 may be any valve capable of manually or automatically releasing pressure when necessary. FIG. 5 illustrates an embodiment in which the relief valve 148 is provided on the chemical pump assembly 16. It will be understood that the relief valve 148 functions similarly in an embodiment in which the relief valve 148 is provided on the dressing 14. Referring to FIG. 5, the relief valve 148 includes a flexible cap 160 that protrudes into the chemical pump housing 80 connected to a post 162. The flexible cap 160 generally covers an opening 164. The flexible cap 160 may be made of an elastic material. When the pressure difference between the surroundings and the dressing 14, or the surroundings and the chamber 84 in the chemical pump assembly 16, falls outside of a predetermined pressure range, which may be set, for example, between 50 mmHg and 200 mmHg, the flexible perimeter 190 of the flexible cap 160 is sucked into the chemical pump housing 80 or the drape 40. When the flexible perimeter 190 of the flexible cap 160 is pulled toward the inside of the chemical pump housing 80 or dressing 14, a space is created around the flexible cap 160, allowing air to pass through the opening 164. If the opening 164 is not covered by the flexible cap 160, the flexible perimeter 190 of the flexible cap 160 will relax on the inner surface of the chemical pump housing 80, allowing air from the surroundings to enter the chemical pump assembly 16 or dressing 14 until the internal pressure reaches a pressure that reseals the opening 164. The chemical pump assembly 16 and / or dressing 14 then experience the amount of negative pressure at which the relief valve 148 reseals, which may be a pressure range within the therapeutic range, for example, between 50 mmHg and 200 mmHg, but may be different from the pressure differential at which the opening 164 opens.

[0037] In another embodiment, as shown in FIG. 5A, a two-way valve 184 is provided on the chemical pump housing 80 instead of the first valve 192 and the relief valve 148. Alternatively, the two-way valve 184 may be provided on at least one dressing member 14. In yet another embodiment, the two-way valve 184 may be similar in structure to the valve described in U.S. Pat. No. 5,439,143. The chemical pump assembly 16 may be in fluid communication with the enclosed space 60 through the two-way valve 184. Alternatively, the mechanical pump assembly 18 may also be in fluid communication with the enclosed space 60 through the two-way valve 184. As shown in FIG. 15, the hose 62 may be attached to the mechanical pump assembly 18 and inserted into the two-way valve 184. As a result, the mechanical pump assembly 18 is in fluid communication with the enclosed space 60.

[0038] The two-way valve 184 may include three operating states. In a first operating state, gas can exit the chamber 84 and / or the enclosed space 60 through the two-way valve 184 when the external pressure is lower than the pressure of the enclosed space 60 and / or the chamber 84. In a second operating state, the two-way valve 184 prevents gas from entering or exiting the enclosed space 60 and / or the chamber 84 through the two-way valve 184 when the pressure of the chamber 84 and / or the enclosed space 60 is between a first predetermined threshold and a second predetermined threshold. In a third operating state, the two-way valve 184 allows gas from the environment to enter the enclosed space 60 and / or the chamber 84 through the two-way valve 184 when the pressure of the enclosed space 60 and / or the chamber 84 is lower than a predetermined threshold. In one embodiment, the predetermined threshold is 560 mmHg, i.e., 200 mmHg below atmospheric pressure. In yet another embodiment, the two-way valve 184 may include a spring that automatically activates the two-way valve 184 when the pressure differential is at a first or second predetermined threshold.

[0039] In yet another embodiment, the mechanical pump assembly 18 is connected to multiple dressings. Additionally, the mechanical pump assembly 18 can be connected to multiple dressings simultaneously. For example, the mechanical pump assembly 18 may be connected to a second dressing 188. The hose 62 may include a Y-joint 186 for simultaneously connecting the mechanical pump assembly 18 to the dressing 14 and the second dressing 188. Additionally, the chemical pump assembly 16 may be connected to multiple dressings or may be simultaneously connected to multiple dressings. As shown in FIG. 14, the hose 62 may include a Y-joint 186 for simultaneously connecting the chemical pump assembly 16 to the dressing 14 and the second dressing 188.

[0040] Hereinafter, a method of implementing negative pressure treatment using the negative pressure kit 10 will be described. First, at least one dressing member 14 is removed from the tray kit 12, and the drape release liner is peeled off to expose the adhesive 66 on the underside of the drape edge 54. The drape edge 54 is placed on the skin S around at least one treatment site 28 and secured to the skin S by the adhesive 66.

[0041] 8, the drape 40 is secured over the dressing site 28 and the seal member 96 of the chemical pump assembly 16 is introduced into the fitting 44 on the drape 40. The seal member 96 is placed over the fitting 44 and the flap 98 is opened. With the flap 98 opened, the chemical pump assembly 16 is in fluid communication with the dressing 14. The reactor 82 begins to consume the selected gas from the enclosed space 60, but is not yet complete at this point.

[0042] Then, as shown in FIG. 9, the mechanical pump assembly 18 is inserted into the first valve 92 provided in the chemical pump assembly 16, and the flap 94 is opened. When the flap 94 is opened, the mechanical pump assembly 18 is in fluid communication with the chamber 84 in the chemical pump assembly 16. Alternatively, the mechanical pump assembly 18 is inserted into the two-way valve 184. The mechanical pump assembly 18 is also in fluid communication with the enclosed space 60 via the chemical pump assembly 16. When the mechanical pump assembly 18 is in fluid communication with the chemical pump assembly 16, the actuator 144 is used to activate the operation of the mechanical pump assembly 18, as shown in FIG. 10. Then, the spring 126 pushes the piston 128 toward the inner wall 122. When the piston 128 moves, air enters the first chamber 138 of the mechanical pump assembly 18, and the dressing member 14 is pulled toward the skin S. The mechanical pump assembly 18 is then removed, and the flap 94 of the first valve 92 is closed by its elastic force, as shown in FIG. 11. In an embodiment having a two-way valve 184, the two-way valve 184 moves to the second operating state when the mechanical pump assembly 18 is removed from the two-way valve 184. The reactor 82 in the chemical pump assembly 16 may continue to reduce or maintain the reduced pressure in the dressing 14. As a result, the pressure in the dressing 14 is reduced to a negative pressure, and the negative pressure indicator 100 signals when the negative pressure is achieved. If the reduced pressure falls below the target pressure range, the relief valve 148 or the two-way valve 184 releases pressure as necessary to restore the reduced pressure to the predetermined pressure difference.

[0043] In another embodiment, the mechanical pump assembly 18 may be inserted before the chemical pump assembly 16. First, at least one dressing 14 is placed and secured over at least one dressing site 28. Then, the mechanical pump assembly 18 is connected to the fitting 44 on the dressing 14 by the hose 62. Alternatively, the first valve 92 or the two-way valve 184 is provided on the dressing 14 instead of the chemical pump assembly 16, providing direct fluid communication between the dressing 14 and the mechanical pump assembly 18. As a result, the mechanical pump assembly 18 is in fluid communication with the enclosed space 60. The first valve 92 or the two-way valve 184 may also be replaced by the fitting 44. In these alternative embodiments, the mechanical pump assembly 18 is inserted into the first valve 92 or the two-way valve 184 on the dressing 14.

[0044] After the mechanical pump assembly 18 is connected to the dressing 14, the mechanical pump assembly 18 is actuated by an actuator, which causes the piston 128 to move toward the inner wall 122 and causes air to enter the first chamber 138 of the mechanical pump assembly 18. The mechanical pump assembly 18 is removed and replaced with the chemical pump assembly 16. The reactor 82 in the chemical pump assembly 16 begins to react with the selected gas in the air to maintain negative pressure in the dressing 14. Once negative pressure in the enclosed space 60 is achieved, an indicator on the dressing 14 and / or chemical pump assembly 16 signals when negative pressure is reached in the dressing 14. If necessary, the relief valve 148 or two-way valve 184 releases pressure when the reduced pressure falls below the target pressure range.

[0045] In yet another embodiment, both the chemical pump assembly 16 and the mechanical pump assembly 18 are connected to at least one dressing member 14. In this embodiment, a first valve, fitting, or hose, and a second valve, fitting, or hose are provided on the dressing member 14. The chemical pump assembly 16 is connected to the dressing member 14 via the first valve, fitting, or hose. The mechanical pump assembly 18 is connected to the second valve, fitting, or hose. For example, the chemical pump assembly 16 is connected to the dressing member 14 via a fitting 44 located on the dressing member 14, as shown in FIG. 12, and the mechanical pump assembly 18 is connected to the dressing member 14 via a hose 62 and a second fitting 166 provided on the dressing member 14. Also, the chemical pump assembly 16 may be replaced with an electromechanical pump similar to those currently used in known negative pressure wound therapy devices, particularly in the case of dressing members 14 that include at least one relief valve similar to the relief valve 148 described above. However, unlike known negative pressure wound therapy devices, the relief valve(s) on the dressing member 14 can be opened and closed (as described above) to maintain the pressure in the enclosed space below the dressing member within a therapeutic range. Also, instead of a relief valve, the dressing member 14 can include a bidirectional valve similar to bidirectional valve 184 that can cooperate with the mechanical pump assembly 18, while an electromechanical pump similar to those currently used in known negative pressure wound therapy devices can be connected to fitting 44 shown in FIG.

[0046] Additionally, at least one attachment for storing the hose 62 may be provided on the mechanical pump assembly 18 or the chemical pump assembly 16. An example of such an attachment is, but is not limited to, a wrap element. With reference to FIG. 13, the chemical pump assembly 16 may include a wrap element 176 provided on the chemical pump housing 80 around which the hose 62 may be wrapped. Alternatively, the wrap element 176 may be provided on the mechanical pump housing 120. The hose 62 may be wrapped around the at least one attachment such that the hose 62 is secured during storage and transportation. In another embodiment, the hose 62 may be housed within the chemical pump assembly 16. In yet another embodiment, the hose 62 may be housed within the mechanical pump assembly 18. Alternatively, the tray kit 12 may include an additional recess for storing the hose 62.

[0047] 16 and 17, an alternative mechanical pump assembly 200 is shown. The mechanical pump assembly 200 includes opposed proximal and distal ends 202 and 204. The mechanical pump assembly 200 includes a mechanical pump 206 and a pump chamber 208 that is fluidly connectable to an inner chamber 212 of a chemical pump housing 214 of a chemical pump assembly 216 (FIGS. 18-22) and / or an enclosed space 60' of a negative pressure assembly 218 (FIGS. 23 and 24), which will be described in more detail below.

[0048] 16 and 17, the mechanical pump assembly 200 may include a charge button 220, an actuator 222, and a biasing mechanism (not shown, similar to spring 126 in FIG. 7) operably connected to a moveable pump element (not shown, similar to piston 128 in FIG. 7). In practice, the charge button 220 may be actuated to vent air from the pump chamber 208 and define a charge position (e.g., when depressed, moves from the distal end 204 toward the proximal end 202) as shown in FIG.

[0049] An internal assembly within the mechanical pump assembly 200 ensures that the charge button 220 remains in the charge position until the actuator 222 is actuated. Actuation of the actuator 222 causes a biasing mechanism to move the movable pump and draw air into the pump chamber 208. As a result, a negative pressure is created within the pump chamber 208. For reference, FIG. 16 shows the mechanical pump assembly 200 after the actuator 222 has been actuated.

[0050] The mechanical pump assembly 200 also includes a nozzle 224 disposed at the proximal end 202. With continued attention to Figures 16 and 17, the nozzle 224 may be received by a shroud 226 that at least partially surrounds the nozzle 224. The shroud 226 in the illustrated embodiment is plunger shaped.

[0051] A shroud 226 may be provided at the proximal end 202 of the mechanical pump assembly 200. The shroud 226 may be made from any number of materials that provide sufficient flexibility and rigidity to allow for a fluid-tight seal between the mechanical pump 206 and an object to which the mechanical pump assembly 200 is to be connected.

[0052] It should be noted that the mechanical pump assembly 200 may be used without the shroud 226, as shown in FIG 22, or may not include the shroud 226 in certain circumstances. If a shroud 226 is used, the shroud 226 may contact the drape 40' of the negative pressure assembly 218, as shown in FIG 24 and described in more detail below. Additionally, the shroud 226 defines an interior volume 228 that may be provided for fluidics between the enclosed space 60' and the pump chamber 208.

[0053] 16 and 17, the shroud 226 includes a sealing lip 232, a barrel portion 234, a cup portion 236, and a joint region 238. The sealing lip 232, the barrel portion 234, the cup portion 236, and the joint region 238 may all be made of the same material(s). Alternatively, the sealing lip 232, the barrel portion 234, the cup portion 236, and the joint region 238 may be made of different materials.

[0054] The sealing lip 232 interfaces with the drape 40' and defines a sealing lip inner diameter 232a and a sealing lip outer diameter 232b. The sealing lip inner diameter 232a and the sealing lip outer diameter 232b may be of uniform diameter when extending in the proximal-distal axial direction. The sealing lip 232 may include an engagement surface 232c that directly interfaces with the drape 40' and / or the chemical pump housing 214, thereby ensuring favorable fluid communication between the mechanical pump assembly 200 and the inner chamber 212 of the chemical pump housing 214 of the chemical pump assembly 216 or the enclosed space 60' of the negative pressure assembly 218.

[0055] The barrel portion 234 defines an inner barrel diameter and an outer barrel diameter. The inner barrel diameter and the outer barrel diameter may each maintain a uniform diameter when extending in the proximal-distal axial direction. The barrel portion 234 may include a mounting surface 234a disposed on an opposite side of the shroud 226 from the sealing lip 232 and facing away from the engagement surface 232c of the sealing lip 232. The mounting surface 234a may be in direct contact with the mechanical pump 206. The mounting surface 234a may be slightly offset from the mechanical pump 206. The nozzle 224 is received in the shroud 226 and is in direct contact with the inner diameter of the barrel portion 234 of the shroud 226.

[0056] The cup portion 236 is disposed between the sealing lip 232 and the barrel portion 234. The cup portion 236 defines a cup portion outer diameter that decreases in size as it extends from the sealing lip 232 toward the barrel portion 234. Additionally, the cup portion 236 defines a cup portion maximum outer diameter at its junction with the sealing lip 232. Additionally, the cup portion 236 defines a cup portion minimum outer diameter at its junction with the junction region 238. Additionally, the cup portion minimum outer diameter is greater than or equal to the barrel portion outer diameter at its junction with the barrel portion outer diameter.

[0057] Finally, a juncture region 238 is provided between the barrel portion 234 and the cup portion 236. Additionally, the juncture region 238 defines a juncture region outer diameter 238a that increases in size as it extends from the barrel portion 234 to the cup portion 236. However, the sealing lip outer diameter 232b is greater than the juncture region outer diameter 238a.

[0058] The foregoing layout of the shroud 226, and more particularly the components that make up the shroud 226, provides a number of advantages. For example, the shroud 226 does not penetrate the valve 244 (FIGS. 21 and 24), as described in more detail below, thereby minimizing the risk of undesirable material entering the inner chamber 212 or enclosed space 60'. Additionally, as also described in more detail below, the compact size ensures easy and good fluid engagement with the valve 244, allowing air to be easily and quickly evacuated from the inner chamber 212 and enclosed space 60'.

[0059] The mechanical pump assembly 200 may be utilized with a variety of components. For example, as shown in Figures 21 and 22, the mechanical pump assembly 200 may be utilized with a chemical pump housing 214 of a chemical pump assembly 216 that includes a reactor 242. The reactor 242 may be similar to the chemical pump 82 described above. As shown in Figure 22, the mechanical pump assembly 200 cooperates with a valve 244 of the chemical pump housing 214 to provide a desired negative pressure within the inner chamber 212 and beneath a dressing in fluid communication with the inner chamber 212.

[0060] 18-22, the chemical pump housing 214 of the chemical pump assembly 216 includes at least one wall 256 that defines the inner chamber 212. The at least one wall 256 may include an upper wall 258, a lower wall 262, and at least one side wall 264. The upper wall 258 is spaced from the lower wall 262 by the inner chamber 212. As shown in FIG. 19, the lower wall 262 may define an opening 266 for receiving the valve 244, although the opening 266 and the valve 244 may be located elsewhere and on other walls of the chemical pump housing 214.

[0061] The upper wall 258 may include an upper wall outer surface 258a and an upper wall inner surface 258b. Additionally, the lower wall 262 may include a lower wall outer surface 262a and a lower wall inner surface 262b. As shown, the lower wall inner surface 262b faces in the opposite direction from the lower wall outer surface 262a and in the same direction as the upper wall outer surface 258a. A slit 248 may be provided in the upper wall 258 to receive the pull tab 252.

[0062] 18, the pull tab 252 may include a first pull tab 252a and a second pull tab 252b. In one embodiment, the first pull tab 252a and the second pull tab 252b are separate elements, while in another embodiment, the first pull tab 252a and the second pull tab 252b may be connected or integrated.

[0063] The reactor 242 is disposed within the inner chamber 212. Additionally, a first pull tab 252a extends from the inner chamber 212 through the slit 248 into the air, and a removable layer 254 is connected to the pull tab 252 to protect the reactor 242 until the removable layer 254 is removed. The reactor 242 is configured to react with a selected gas in the air and consumes the selected gas when the reactor 242 is exposed to air. In the illustrated embodiment, the reactor 242 is configured to react with a selected gas in the air, for example, oxygen.

[0064] In the illustrated embodiment, an elongated slit 248 is provided in chemical pump housing 214 of chemical pump assembly 216. When slit 248 is uncovered, inner chamber 212 is exposed to the environment. A pull tab 252 extends from inner chamber 212 through slit 248 to the environment.

[0065] The packet 268, including the removable layer 254, covers the reactor 242 such that the reactor 242 is not exposed to the environment until after the removable layer 254 is removed from the packet 268. The packet 268 may be a foil packet 268 that seals the perimeter of the reactor 242. The first pull tab 252a extends through the slit 248 and is connected to the removable layer 254. The first pull tab 252a may be pulled to remove the first pull tab 252a from the slit 248.

[0066] When the first pull tab 252a is pulled through the slit 248, the removable layer 254 is removed from the packet 268 through the slit 248 and, optionally, from the inner chamber 212, exposing the reactor 242 to the environment. After the removable layer 254 is removed, the reactor 242 begins to react with the selected gas, e.g., oxygen, within the inner chamber 212. The first pull tab 252a is preferably removed after connection to the dressing 14', as described in more detail below. However, the first pull tab 252a may be removed prior to affixing the pump assembly to the dressing 14'.

[0067] The second pull tab 252b is connected to a thin film 282 disposed over and attached to a portion of the top wall outer surface 258a. The thin film 282 includes a flap 284, and the slit 248 is disposed under the flap 284, as shown in FIG. 22. The second pull tab 252b is connected to a release layer 286 (shown in dashed lines in FIG. 18) disposed on the underside of the flap 284. The release layer 286 covers the adhesive disposed on the underside of the thin film 282. When the second pull tab 252b is pulled, the second pull tab 252b separates the release layer 286 from the flap 284, exposing the adhesive disposed on the underside of the flap 284. The flap 284 then moves toward the top wall outer surface 258a, covering the remaining portion of the top wall outer surface 258a, thereby covering the slit 248. As a result, the inner chamber 212 is no longer exposed to the environment through the slit 248. When the membrane 282 covers the slit 248, the reactor 242 reacts with the selected gas in the enclosed space 60, 60' under the dressing, if already connected to the dressing via the hose 62', creating a closed system. Thus, a closed space is created when the pressure is reduced. When the inner chamber 212 is under negative pressure, the membrane 282 is drawn through the slit 248 towards the inner chamber 212. In this way, the membrane 282 cooperating with the slit 248 can indicate to a user that the inner chamber 212 is under negative pressure. An indicator 290, e.g., a line, a cross, etc., may also be provided on the membrane 282 adjacent the slit 248 to provide a further indication of negative pressure.

[0068] 18-22, the chemical pump housing 214 of the chemical pump assembly 216 may further include a hose fitting 274. The hose fitting 274 may be tubular and include a passageway that communicates with the inner chamber 212. In one embodiment, the hose fitting 274 is disposed on the side of the chemical pump housing 214 opposite the slit 248. The hose fitting 274 may be disposed in a recess in the chemical pump housing 214, although the hose fitting 274 may be disposed on any surface of the chemical pump housing 214.

[0069] The hose 62' is attached to a hose fitting 274 to connect the pump assembly to the dressing 14'. As shown in FIG. 20, the chemical pump housing 214 of the chemical pump assembly 216 may be connected to multiple dressings simultaneously. In particular, the hose 62' may include a Y-fitting 186 to simultaneously connect the chemical pump housing 214 to the dressing 14' and a second dressing 188. It should be noted that FIG. 20 merely illustrates the connections diagrammatically and is in no way limiting. For example, the chemical pump housing 214 may be connected to dressings as shown in FIGS. 23 and 24.

[0070] 19, 21 and 22, the valve 244 is provided in the chemical pump housing 214 so as to be in fluid communication with the inner chamber 212. Alternatively, the valve 244 may be provided in the drape 40' as shown in FIGS. 23 and 24. For reference, the valve 244 provided in the chemical pump housing 214 and the valve 244 provided in the drape 40' have the same structure. For ease of understanding, the valve 244 provided in the chemical pump housing 214 will be described first.

[0071] The valve 244 includes at least one movable element 244a for blocking the opening 266 and a mounting portion 244b flush with at least one wall 256. The mounting portion 244b of the valve 244 may directly interface with the bottom wall 262 of the chemical pump housing 214 to mount the valve 244 thereto. The mounting portion 244b may also be recessed or received further into the inner chamber 212 than shown in FIGS. 19, 21, and 22, or a boss may extend from the bottom wall outer surface 262a around the opening 266. By recessing the valve 244 into the inner chamber 212 or surrounding the opening 266 with a boss, the movable element 244a is protected from contact as it moves toward the dome shape, similar to that shown in FIG. 24, during operation of the mechanical pump assembly 200. As discussed herein, the opening 266 may be provided in the bottom wall 262 of the chemical pump housing 214. However, it will be understood that the opening 266, and thus the valve 244, may be provided in other walls of the chemical pump housing 214 (e.g., the top wall 258, at least one side wall 264) without departing from the scope of the present disclosure.

[0072] The valve 244 may be received in the bottom wall 262 such that the distance between the top wall inner surface 258b and the bottom wall outer surface 262a is greater than the distance between the top wall inner surface 258b and the valve 244. Additionally, the distance between the movable element 244a of the valve 244 and the top wall 258 is less than the distance between the mounting portion 224b and the top wall 258.

[0073] The movable element 244a is disposed such that it does not protrude outwardly beyond an outer surface of the at least one wall 256. For example, the at least one wall 256 may be the bottom wall 262. Such an orientation of the valve 244 has a number of advantages. For example, in this orientation, the valve 244 cannot be accidentally actuated. Furthermore, the risk of the valve 244 inadvertently contacting an object external to the chemical pump housing 214 is reduced.

[0074] Attention is now directed to Figures 23 and 24, where a dressing 14' is shown. For reference, the dressing 14' of Figures 23 and 24 is similar to the dressing 14 shown in Figure 2, unless otherwise noted. It is to be noted that the opening 48 of the dressing 14' of Figures 23 and 24 includes the valve 244 previously described with reference to Figures 18-22, as compared to the fitting 44 of Figure 2. Furthermore, the dressing 14' of Figures 23 and 24 may include a boss 278 surrounding the valve 244 to attach the valve 244 to the drape 40'. The boss 278 provides additional structural stability to the arrangement and provides sufficient recess for the valve 244 to protect the movable element 244a from interference due to external contact. Thus, the boss 278 may abut the drape top 52' of the drape 40'. As these are the main differences, only an abbreviated description of Figures 23 and 24 will be given. It will be appreciated that Figures 23 and 24 are schematic and not drawn to scale, especially considering that the drape 40' may be made from a thin film.

[0075] The negative pressure assembly 218 includes a drape 40' for covering the treatment site on the patient. The negative pressure assembly 218 is capable of maintaining a negative pressure under the drape 40' when reduced pressure is applied and sealed against the skin S. The vacuum may be provided by the chemical pump housing 214 and / or the mechanical pump 206. The negative pressure assembly 218 also includes a sealing element 46 that cooperates with the drape 40' to define an enclosed space 60' when applied against the skin S. The enclosed space 60' is covered by the drape 40' and surrounded by the sealing element 46.

[0076] Similar to the valve 244 shown in Figs. 19, 21 and 22, the valve 244 shown in Figs. 23 and 24 has a first operating state in which gas can pass through the valve 244 to exit the enclosed space 60' and a second operating state in which gas is prevented from entering or exiting the enclosed space 60' through the valve 244. The valve 244 opens (i.e., unsealed or first operating state) at a predetermined pressure to allow gas to be removed from the inner chamber 212 / enclosed space 60' while preventing gas from entering the inner chamber 212 / enclosed space 60' and then closes (i.e., sealed or second operating state). Of note, when the operating pressure is reached, the valve 244 opens and allows gas to flow. And also, when the operating pressure is no longer reached, the valve 244 automatically closes and stops the movement of gas into or out of the inner chamber 212 / enclosed space 60'.

[0077] The valve 244 may have a tortuous flow path and allow for bidirectional flow. Additionally, the valve 244 may be made of various elastomeric materials including, for example, silicone, hydrocarbon resistant fluorosilicone rubber, fluoroelastomers, and perfluoroelastomers. Additionally, the valve 244 may include various cuts 246 in the movable element 244a to allow for the passage of gas therethrough (i.e., communication between the surroundings and the inner chamber 212 / enclosed space 60'). For example, it is contemplated that the valve 244 may have a single cut or multiple cuts. Additionally, the cuts 246 may define straight lines, curves, shapes, or combinations thereof. For example, the cuts may be in the shape of an X or a cross.

[0078] By way of example only, valve 244 may include an X-cut and be made of a 50 durometer silicone material, which allows valve 244 to open (i.e., unsealed) at approximately 60 mmHg and close (i.e., resealed) at approximately 55 mmHg. Alternatively, valve 244 may be made of a 60 durometer silicone material with an X-cut, open at approximately 120 mmHg, and close at approximately 85 mmHg. With an X-cut, valve 244 may release pressure very slowly and the X may not fully realign after actuation.

[0079] As another example, and in no way limiting, the valve 244 may have a single cut 3.85 mm long and be made from a 60 durometer silicone material, such that the valve 244 opens at 180 mmHg and the valve 244 exhibits excellent resealability. As another non-limiting example, the valve 244 may have a single 2.55 mm slit with a 60 durometer silicone material, such that the valve 244 may open at 220 mmHg.

[0080] 21 and 22, the pump chamber 208 of the mechanical pump 206 can be fluidly connected to the inner chamber 212 via the valve 244 to draw air from the inner chamber 212 into the pump chamber 208. Further, the mechanical pump 206 is configured to draw air from the inner chamber 212 into the pump chamber 208 when the valve 244 is in fluid communication with the inner chamber 212 without penetrating the mechanical pump 206. As shown in FIG. 21, the mechanical pump 206 is configured to draw air from the inner chamber 212 into the pump chamber 208 when the mechanical pump 206 is in fluid communication with the inner chamber 212 without penetrating the valve 244.

[0081] 24, the mechanical pump 206 and the pump chamber 208 of the mechanical pump assembly 200 are fluidly connectable to the enclosed space 60' via the valve 244 when the valve 244 is in a first operating state. The mechanical pump 206 is configured to fluidly connect to the enclosed space 60' and draw air from the enclosed space 60' into the pump chamber 208 of the mechanical pump assembly 200 while being offset from the at least one moving element 244a. Additionally, the mechanical pump 206 is configured to draw air from the enclosed space 60' into the pump chamber 208 when the mechanical pump assembly 200 is fluidly connected to the enclosed space 60' without penetrating the valve 244.

[0082] A method for achieving negative pressure therapy is described below: A drape 40' may be applied over the treatment site 28 of the patient, the drape 40' may be sealed against the patient's skin S to define an enclosed space 60' covered by the drape 40', and a chemical pump may be activated to consume a selected gas within the enclosed space 60'.

[0083] The method may also include positioning the mechanical pump assembly 200 such that the mechanical pump assembly 200 is in fluid communication with the enclosed space 60' via the two-way valve 244, and depleting air from the enclosed space 60' with the mechanical pump 206, all portions of the mechanical pump 206 spaced apart from the two-way valve 244. Further, when air is depleted from the enclosed space 60', the two-way valve 244 does not penetrate the mechanical pump 206, and when air is depleted from the enclosed space 60', the mechanical pump 206 does not penetrate the two-way valve 244.

[0084] 25 illustrates an embodiment in which a mechanical pump assembly 300 and a chemical pump assembly 302 are provided together. The chemical pump assembly 302 is similar in many respects to the chemical pump assembly 216 described above, and therefore the chemical pump assembly 302 will not be described in detail. The chemical pump assembly 302 includes a chemical pump housing 304. A slit 306 similar to the slit 248 described above is provided in the chemical pump housing 304. A hose fitting 308 is also provided in the chemical pump housing 304 and is in fluid communication with an inner chamber 312 of the chemical pump housing 304.

[0085] A reactor 320, similar to reactor 242 described above, is provided within the inner chamber 312. The reactor 320 is configured to react with gas in the air to consume the gas. In the illustrated embodiment, the reactor 320 is sealed within a packet 322 that includes a removable layer 324. A first pull tab 330 extends from the periphery through a slit 306 and connects with the removable layer 324. The first pull tab 330 may be pulled through the slit 306 to remove the removable layer 324 from the packet 322, thus exposing the reactor 320 to the air within the inner chamber 312.

[0086] A membrane 332 is provided on the exterior of the chemical pump housing 304. The membrane 332 includes a flap 334 having an underside with a release layer (not visible in FIG. 25) that covers the adhesive on the underside of the flap. A second pull tab 336 is connected to the release layer on the flap 334. Pulling the second pull tab 336 removes the release layer, thereby exposing the adhesive on the flap 334. With the adhesive exposed, the flap 334 can be brought over the slit 306 in a manner similar to that of the chemical pump assembly 216 described above.

[0087] In the embodiment shown in FIG. 25, a chemical pump assembly and a mechanical pump assembly are combined into a single unit. The embodiment shown in FIG. 25 also includes a valve 350 including at least one movable element 352. However, the valve 350 is disposed within an inner chamber 312 as opposed to being exposed to the exterior of the housing as with the valve 242 shown in FIG. 19. The mechanical pump assembly 300 includes a pump chamber 360 that is fluidly connectable with an enclosed volume (see, e.g., enclosed volume 60 shown in FIG. 3) beneath a dressing (similar to dressing 14 shown in FIG. 3) when a hose (similar to hose 62′ in FIG. 20) is provided at a fitting 308 that connects the dressing to the assembly shown in FIG. 25.

[0088] The mechanical pump assembly 300 includes a mechanical pump housing 362 that defines a pump chamber 360. A piston 364 is disposed in the mechanical pump housing 362 to define the pump chamber 360. The piston 364 may be connected to a rod 366 in a conventional manner. A biasing mechanism, which in the illustrated embodiment is a spring 368, acts to bias the piston 364 to expand the pump chamber 360 (to the left as shown in FIG. 25 ).

[0089] To actuate the mechanical pump assembly 300, an actuator 380 is provided, which may be a button covered by a resilient cover 382 airtightly connected to the chemical pump housing 304. As shown in FIG. 25, the mechanical pump assembly 300 is shown before actuation, and therefore before drawing air from an enclosed space (e.g., enclosed space 60 in FIG. 3). The actuator 380 is operatively connected to the rod 366. Actuation of the actuator 380, e.g., pushing the actuator 380 to the right (in the orientation shown in FIG. 25) against the biasing force of the spring 368, causes air to be expelled from the pump chamber 360 by the outlet valve 386, which is connected to the environment via an outlet air line 388. When the force on the actuator 380 is removed, the spring 368 biases the piston to the left (in the orientation shown in FIG. 25). Thus, air within the inner chamber 312 and the enclosed volume (see, e.g., enclosed space 60 in FIG. 3) is drawn into the pump chamber 360, thus reducing the pressure beneath the dressing. The actuator 380 may then be actuated again until the pressure beneath the dressing reaches the desired pressure. The reactor 320 may then further remove a selected gas, such as oxygen, from the inner chamber 312 and the enclosed volume beneath the dressing.

[0090] The mechanical pump assembly 300 is shown in Figure 25 inside the chemical pump housing 304. Alternatively, the mechanical pump assembly 300 may be external to but connected to the chemical pump housing 304. Also, to prevent the pressure under the dressing from being too low, a relief valve (similar to the relief valve 148 on the chemical pump housing 80 described above) may be provided on the chemical pump housing 304 to relieve pressure as needed.

[0091] It will be appreciated that the various embodiments disclosed above, 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, which are intended to be encompassed by the following claims.

Claims

1. a drape for covering a treatment site on a patient, the drape maintaining a negative pressure beneath the drape when the drape is depressurized and sealed against the skin; a sealing element that cooperates with the drape when applied to the skin to define an enclosed space covered by the drape and surrounded by the sealing element; a reactor disposed relative to the drape and the sealing element such that the reactor is in fluid communication with the enclosed space when the drape is over the treatment site, the reactor configured to react with a selected gas in air and consume the selected gas in the enclosed space; a valve disposed with at least one movable element, the valve having a first operational state in which gas is drawn from the enclosed space through the valve; a mechanical pump assembly including a pump chamber fluidly connectable with the enclosed space via the valve when the valve is in the first operating state, the mechanical pump assembly being fluidly connected with the enclosed space when the valve is in the first operating state and configured to draw air from the enclosed space into the pump chamber of the mechanical pump assembly; The reactor is disposed within a chemical pump housing of a chemical pump assembly, the chemical pump assembly comprising: A slit provided in the chemical pump housing; a first pull tab extending circumferentially through the slit from an inner chamber of the chemical pump housing; a removable layer connected to the first pull tab, the removable layer protecting the reactor from air until the removable layer is removed; the chemical pump assembly further comprising a second pull tab connected to the membrane; the membrane has a portion that covers and seals the slit after the second pull tab is removed. Negative pressure assembly.

2. The negative pressure assembly of claim 1 , wherein the valve is disposed in the drape.

3. 2. The negative pressure assembly of claim 1, wherein the reactor is mounted to the chemical pump housing offset from the drape, and the valve is mounted to the chemical pump housing.

4. 4. The negative pressure assembly of claim 3, wherein the mechanical pump assembly is configured to draw air from the enclosed space into the pump chamber when the mechanical pump assembly is in fluid communication with the enclosed space such that the mechanical pump assembly does not contact the at least one movable element of the valve.

5. 3. The negative pressure assembly of claim 2, wherein the mechanical pump assembly is configured to draw air from the enclosed space into the pump chamber when the mechanical pump assembly is in fluid communication with the enclosed space such that the mechanical pump assembly does not contact the at least one movable element of the valve.

6. 4. The negative pressure assembly of claim 3, wherein the mechanical pump assembly includes a proximal end and a distal end at opposite ends, the mechanical pump assembly including a shroud at least partially surrounding a nozzle at the proximal end, the shroud contacting the drape or the chemical pump housing with the nozzle offset from the at least one movable element of the valve when the air is drawn into the pump chamber from the enclosed space.

7. 3. The negative pressure assembly of claim 2, wherein the mechanical pump assembly includes a proximal end and a distal end at opposite ends, the mechanical pump assembly including a shroud at least partially surrounding a nozzle at the proximal end, the shroud contacting the drape or chemical pump housing with the nozzle offset from the at least one movable element of the valve when the air is drawn into the pump chamber from the enclosed space.

8. A negative pressure assembly as claimed in claim 1, wherein the movable element is configured so as not to protrude outwardly beyond the outer surface of the chemical pump housing.

9. 2. The negative pressure assembly of claim 1, wherein the mechanical pump assembly includes opposed proximal and distal ends, the mechanical pump assembly including a shroud at least partially surrounding a nozzle at the proximal end, the shroud including a sealing lip and a barrel portion defining a barrel portion outer diameter, the barrel portion being on an opposite side of the shroud relative to the sealing lip, the shroud also including a cup portion between the sealing lip and the barrel portion, the cup portion defining a cup portion outer diameter that decreases in size as it extends from the sealing lip toward the barrel portion.

10. 10. The negative pressure assembly of claim 9, wherein the shroud includes a junction area between the barrel portion and the cup portion, the junction area defining a junction area outer diameter that increases in size as it extends from the barrel portion to the cup portion, and the sealing lip defining a sealing lip outer diameter that is larger than the junction area outer diameter.

11. The negative pressure assembly of claim 10 , wherein the cup portion defines a maximum cup portion outer diameter at a junction with the sealing lip and a minimum cup portion outer diameter at a junction with the junction region, the cup portion minimum outer diameter being greater than the barrel portion outer diameter.

12. 2. The negative pressure assembly of claim 1, wherein the reactor is offset from the drape and mounted in the chemical pump housing, and the pump chamber of the chemical pump assembly is mounted in or on the chemical pump housing.

13. The negative pressure assembly of claim 12 , wherein the valve is disposed in or on the chemical pump housing.

14. The negative pressure assembly of claim 12 , wherein the mechanical pump assembly includes an actuator accessible from outside the chemical pump housing.

15. The negative pressure assembly of claim 1 , further comprising a boss surrounding said valve for attaching said valve to said drape.

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