Patent Publication Number: US-2022218529-A1

Title: Reduced pressure device having selectively deliverable electrolyte

Description:
BACKGROUND 
     Negative pressure and reduced pressure are terms used to describe a pressure that is below normal atmospheric pressure. Negative pressure wound therapy (“NPWT”) is utilized for several sites on the skin, such as a wound or an incision. Furthermore, NPWT is useful to manage wounds with complex healing concerns. 
     Negative or reduced pressure therapy may also be used for a therapeutic treatment that utilizes negative pressure for skin treatments and restorative purposes. In these instances the pressure used for skin treatments and restorative purposes may not need to be as low (offset from normal atmospheric pressure) as that used in NPWT. For example, where −80 mmHg to −125 or even −150 mmHg may be desired for NPWT, for skin treatments and restorative purposes the pressure may need to be reduced to only −20 mmHg or −40 mmHg. As such, simply a reduced pressure may be desired in some instances, even including instances where a wound may be treated. 
     It is known to use a vacuum generation source, such as an electromechanical pump, to apply reduced pressure to the inside of a dressing on a dressing site. However, when a vacuum source operates using a chemical reaction in which a gas found in air is consumed to as to reduce the pressure at the dressing site, it is known to isolate a substrate impregnated with a reducing agent and an electrolyte solution from air using an air-tight foil packet. When it is desired to begin the chemical reaction, the substrate is exposed to air by tearing or removing a section of the air-tight foil packet. However, other manners to activate the chemical reaction may be desirable. 
     SUMMARY 
     In view of the foregoing, a reduced pressure device includes a dressing and a reactor. The dressing covers a dressing site and defines an enclosed volume beneath the dressing and around the dressing site. The reactor is disposed with respect to the dressing so as to produce a reduced pressure beneath the dressing when activated. The reactor includes a reducing agent and an electrolyte solution. The electrolyte solution is configured to be selectively delivered to the reducing agent, and the reactor begins to react with at least one selected gas in the enclosed volume after the electrolyte solution is delivered to the reducing agent to consume the at least one selected gas within the enclosed volume. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic cross-sectional view of a reduced pressure device. 
         FIG. 2  is a schematic cross-sectional view of the reduced pressure device according to an alternative arrangement. 
         FIG. 3  is schematic cross-sectional view of a reduced pressure device after rupturing a capsule. 
         FIG. 4  is a schematic cross-sectional view of another reduced pressure device. 
         FIG. 5  is a schematic cross-sectional view of another reduced pressure device. 
         FIG. 6  is a schematic cross-sectional view of another reduced pressure device. 
         FIG. 7  is a perspective view of a dressing connected with a chemical pump housing. 
         FIG. 8  is a schematic cross-sectional view of the chemical pump housing. 
         FIG. 9  is a schematic cross-sectional view of an alternative chemical pump housing. 
         FIG. 10  is a schematic cross-sectional view of an alternative chemical pump housing. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  depicts a reduced pressure device  10  useful for administering negative and/or reduced pressure therapy to a dressing site  12 . Reduced pressure described herein is pressure below atmospheric pressure. The reduced pressure device  10  includes a dressing  14  and a reactor  16 , which operates as a vacuum source. The dressing  14  is placed over the dressing site  12  on a patient&#39;s skin S. The dressing site  12  can be, but is not limited to, a wound, an incision, or skin where there is no wound or incision, for example in a cosmetic application. The reduced pressure device  10 , which can be used for NPWT or for instances where the pressure need not be reduced to what is typically achieved in NPWT, generally includes the dressing  14 , the reactor  16 , a drape  20 , an absorbent element  22 , and a sealing element  24 . The dressing  14  may further include valves, pressure indicators and the like. 
     The drape  20  can be made from a flexible material and can be a thin film capable of maintaining a reduced pressure underneath the drape  20  upon application of a vacuum. The thin film from which the drape  20  is made can be substantially impermeable to liquids but somewhat permeable to water vapor, while still being capable of maintaining reduced pressure underneath the drape  20 . For example, the thin film material from which the drape  20  is made may be constructed of polyurethane or other semi-permeable material such as that sold under the Tegaderm® brand or 9834 TPU tape available from 3M. Similar films are also available from other manufacturers. The drape  20  can be made in a variety of shapes and sizes to cover a variety of dressing sites  12 . 
     The absorbent element  22  is made from an absorbent material that is capable of absorbing exudate from the dressing site  12 . The absorbent element  22  can be made from super absorbent acrylate, absorbent beads, foams, or natural absorbents. The absorbent element  22  can also be a hydroactive wound pad available under the trademark Vilmed®, which chemically absorbs exudate and precludes the exudate from passing through the absorbent element  22  toward the reactor  16  unlike a sponge. 
     The sealing element  24  cooperates with the drape  20  and skin S to create an enclosed volume  32  defined between the drape  20  and the dressing site  12  and surrounded by the sealing element  24 . The reactor  16 , which when activated operates as a vacuum source in fluid communication with the enclosed volume  32 , administers reduced pressure to the enclosed volume  32  so as to control the atmosphere within the enclosed volume  32 . The sealing element  24  can be separate from the dressing  14  or can instead be a component of the dressing  14 . The sealing element  24  functions like a gasket, as the sealing element  24  prevents fluid (including air) from escaping between the drape  20  and the skin S. The sealing element  24  can be made from a material such as silicone or a hydrogel material, for example. 
     The dressing  14  may further include a wound contact layer  36 . The wound contact layer  36  can be made of an elastomeric material, such as a polymeric material that has rubber-like properties. Furthermore, the wound contact layer  36  can be an elastomeric material that is a thin, flexible elastomeric film. Some examples of such materials include a silver coated nylon, a perforated silicone mesh, or other material that will not stick to the patient&#39;s tissue. The wound contact layer  36  can also be a polyurethane film layer in which holes can be provided. A silicone coating can also be provided on a skin-contacting side of the absorbent element  22  instead of the wound contact layer  36 . 
     A drape release liner (not shown in  FIG. 1 ) is disposed on a bottom surface of the drape  20 . The drape release liner is removed before the dressing  14  is applied to the dressing site  12 . When the drape release liner is removed, an adhesive  38  on the bottom surface of the drape  20  is exposed. As the dressing  14  is placed on the patient, the adhesive  38 , which can be an acrylic-based adhesive that is distinct from the sealing element  24 , secures the drape  30  to the patient&#39;s skin S around the dressing site  12 . Thus, contact is maintained between the drape  20  and the skin S. 
     The dressing  14  may also include a membrane  40  between the reactor  16  and the absorbent element  22 . In the embodiment shown in  FIG. 1 , the membrane  40 , which can be a thin film similar to the drape  20 , is fixed to the bottom surface of the drape  20 . The membrane  40  includes at least one opening  42  or is pervious to air so that air is allowed to travel through the membrane  40 . Therefore, the reactor  16  is in fluid communication with the enclosed volume  32 . In an alternative embodiment shown in  FIG. 2 , the membrane  40  can disposed over the dressing site  12  with the absorbent element  22  affixed to it. In this alternative embodiment, the dressing  14  can be what may be referred to as a two-piece dressing in which the membrane  40  and the absorbent element  22  are placed on the patient&#39;s skin S over the dressing site  12 , and then the drape  20  and the components affixed thereto are placed over the membrane  40  and the dressing site  12 . In the embodiment depicted in  FIG. 2 , the membrane  40  would include an adhesive on a lower surface to allow the membrane to adhere to the skin S. The membrane  40  may also include a sealing element (similar to the sealing element  24 ) which would allow the drape  20  to be adhered and sealed to the membrane  40  instead of the skin S. 
     The reactor  16  is configured to react with at least one selected gas found in air to remove the selected gas from air. The reactor  16  is located with respect to the drape  20  and the sealing element  24  so that the reactor  16  can be in fluid communication with the enclosed volume  32 . The reactor  16  consumes the selected gas from the enclosed volume  32  thereby removing the selected gas and reducing the gas pressure. For example, the reactor  16  can be an oxygen scavenger which removes oxygen from the air within the enclosed volume  32  so as to reduce gas pressure within the enclosed volume  32  by approximately 20%. Since the vacuum source in this embodiment is the reactor  16  that consumes a gas found in air (as opposed to a mechanical pump), any leakage around the enclosed volume  32  is important to prevent. Uncontrolled ingress of outside oxygen, which could prematurely use up the reactor  16 , should be prevented or limited from penetrating either through the drape  20  or the sealing element  24  or between the sealing element  24  and the skin S. 
     The reactor  16  includes a reducing agent  50 , such as aluminum, zinc or iron, and an electrolyte solution  52 . An example of a substrate impregnated with a reducing agent and an electrolyte solution is found in U.S. Publication No. 2014/0109890A1. Unlike the heater described in U.S. Publication No. 2014/0109890A1 in which a substrate having the reducing agent and a pad impregnated with the electrolyte solution are packaged in a hermetically sealed foil package, the electrolyte solution  52  is shielded from the reducing agent  50  until reduced pressure beneath the dressing  14  is ready to be administered obviating the need for the hermetically sealed foil package. When reduced pressure therapy is ready to be administered to the dressing  14 , the electrolyte solution  52  is introduced to the reducing agent  50 . The reactor  16  then begins to react with the at least one selected gas, e.g., oxygen, in the enclosed volume  32  to create reduced pressure at the dressing site  12 . As illustrated in  FIG. 1 , the dressing  14  may further include a substrate  54  that includes the reducing agent  50  and a binding agent, such as polytetrafluoroethylene or a polyolefin. The term “substrate” means that the substrate  54  is a solid object, and not merely a mass of powdered chemicals; however, the reducing agent  50  could be provided in the dressing  14  as a mass of powdered chemicals, if desired. 
     In  FIG. 1 , the electrolyte solution  52  is stored in a rupturable capsule  56  disposed adjacent to the reducing agent  50 . The capsule  56  can be any package that can be selectively ruptured to allow liquid contents disposed therein to leak from the package after it is ruptured. The user presses onto a pressing location  58  on the drape  20  over the capsule  56  to break the capsule  56 . Once the capsule  56  is broken, which is shown in  FIG. 3 , the electrolyte solution  52  is delivered to the reducing agent  50 , and the reducing agent  50  begins to react with the at least one selected gas in the enclosed volume  32  so as to consume the selected gas from the enclosed volume  32 . The drape  20  may include a marking  62  disposed on a top surface of the drape  20  above the capsule  56  to indicate where the pressing location  58  is located to provide an indication to a user of the pressing location  58 . The marking  62  may be a circle disposed around a periphery of the pressing location  58 ; however, the marking  62  can be any marking that indicates to a user where the pressing location  58  is located. A button may also be provided at the pressing location  58 . 
     With reference to  FIG. 4 , in another embodiment, an opening, which is in the form of a slit  70  in the illustrated embodiment, is disposed on the drape  20 . A first pull tab  74  extends from beneath the drape  20  to ambient through the slit  70  and is connected to a separable layer  76  of the capsule  56 . The separable layer  76  isolates the electrolyte solution  52  within the capsule  56  and from the reducing agent  50 . The first pull tab  74 , which could also be in the form of a string, can be pulled to remove the first pull tab  74  and the separable layer  76  from the slit  70 . When the first pull tab  74  is pulled, the separable layer  76  is removed from the capsule  56  and, if desired, from the enclosed volume  32  through the slit  70 , exposing the reducing agent  50  to the electrolyte solution  52 . After the removal of the separable layer  76 , the electrolyte solution  52  is delivered to the reducing agent  50 , which begins to react with a selected gas, e.g., oxygen, in the enclosed volume  32 . 
     A second pull tab  78  is connected to a cover layer, which can be a thin film  82  placed over and adhered to a portion of the top surface of the drape  20 . The thin film  82  could be made integral with the drape  20 . The thin film  82  can include a flap  84  and, as depicted in  FIG. 4 , the slit  70  is disposed underneath the flap  84 . The second pull tab  78  can be connected to or provided as a release layer provided on a bottom surface of the thin film  82  in the region of the flap  84 . The release layer covers an adhesive (not visible in  FIG. 4 ) on a bottom surface of the thin film  82 . When the second pull tab  78  is pulled, which occurs after the first pull tab  74  has been removed from the slit  70 , the second pull tab  78  disconnects the release layer from the flap  84  and the adhesive disposed on the bottom surface of the flap  84  is exposed. The flap  84  is then moved towards the drape  20  to cover the slit  70 . When the thin film  82  covers the slit  70 , the reactor  16  is closed off from ambient and reacts with the selected gas found in the enclosed volume  32  under the dressing  14 . Reduced pressure is therefore developed in the enclosed volume  32 . 
     Referring to  FIG. 5 , the electrolyte solution  52  can be injected into the dressing  14  when reduced pressure therapy is ready to be administered. For example, the electrolyte solution  52  can be injected into the substrate  54  having the reducing agent  50  or into a mass of powdered chemicals making up the reducing agent  50  by a syringe  90 . An injection port  92  can be disposed on the drape  20  for guiding a user for injecting a needle  94  of the syringe  90  into the substrate  54  or mass of powdered chemicals making up the reducing agent  50 . When reduced pressure is ready to be administered, the user injects the electrolyte solution  52  into the substrate  54  to impregnate the substrate  54  with the electrolyte solution  52  or into the mass of powdered chemicals making up the reducing agent  50 . Once the reducing agent  50  is wetted with the electrolyte solution  52 , the reactor  16  begins to react with the selected gas in the enclosed volume  32  and consuming the selected gas. After finishing injecting the electrolyte solution  52  into the dressing  14 , the injection port  92  can be covered with a thin film in a similar manner to the slit  70  shown in  FIG. 4 . 
     In yet another embodiment, with reference to  FIG. 6 , the electrolyte solution  52  can be stored in a flexible chamber  130  until the reduced pressure therapy is ready to be administered. The flexible chamber  130  can be located externally from the dressing  14 . The flexible chamber  130  is connected to the substrate  54  having the reducing agent  50  or the mass of powdered chemicals making up the reducing agent  50  by a flow conduit  132 . The flow conduit  132  can further include a seal  138 . The seal  138  can be located at any portion of the flow conduit  132 . When reduced pressure therapy is to be administered, the flexible chamber  130  is pressed and/or squeezed and the flow pressure of the electrolyte solution  52  breaks the seal  138 , and the electrolyte solution  52  is delivered to the substrate  54  or the mass of powdered chemicals making up the reducing agent  50 . 
       FIG. 7  depicts an example in which the reactor  16  is positioned outside of the dressing  14  while still being positioned with respect to the dressing  14  so as to produce a reduced pressure beneath the dressing  14  when activated. The reactor  16  is positioned within a chemical pump housing  150 . The chemical pump housing  150  can either connect directly to a fitting  152  provided on the dressing  14  via a fitting or valve  154  ( FIG. 8 ) on the chemical pump housing  150  or can connect via a hose (not shown) to the dressing  14  via the fitting  152  or something similar. When properly connected with the dressing  14 , an inner chamber  156  of the chemical pump housing  150  is in fluid communication with the enclosed volume  32 . 
     Where the chemical pump housing  150  is made from a rigid plastic, a flexible section or button  160  can be disposed on a surface of the chemical pump housing  150 . The flexible section or button  160  is preferably disposed on a top surface of the chemical pump housing  150 . The flexible section or button  160  can be aligned with the capsule  56  so as to be a pressing location where a user can press to break the capsule  56  containing the electrolyte solution  52 . After the capsule  56  is ruptured, the electrolyte solution  52  is delivered to the substrate  54  or mass of powdered chemicals making up the reducing agent  50 . Similar to that described above, after the reducing agent  50  is wetted with the electrolyte solution  52 , the reactor  16  begins to consume the selected gas in the enclosed volume  32  and the inner chamber  156 . 
     With reference to  FIG. 9 , a slit  170  is disposed on the chemical pump housing  150  instead of the dressing  14 . When the slit  170  is disposed on the chemical pump housing  150 , a first pull tab  174  extends from the inner chamber  156  to ambient and is connected to a separable layer  176  of the capsule  56 . The separable layer  176  isolates the electrolyte solution  52  within the capsule  56  and from the reducing agent  50 . The first pull tab  174 , which could also be in the form of a string, can be pulled to remove the first pull tab  174  and the separable layer  176  from the slit  170 . When the first pull tab  174  is pulled, the separable layer  176  is removed from the capsule  56  and, if desired, from the inner chamber  156  through the slit  170 , exposing the reducing agent  50  to the electrolyte solution  52 . After the removal of the separable layer  176 , the electrolyte solution  52  is delivered to the reducing agent  50 , which begins to react with a selected gas, e.g., oxygen, in the inner chamber  156  and the enclosed volume  32 . 
     Also, a cover layer, which can be a thin film  182 , is disposed on the chemical pump housing  150 . A second pull tab  178  is connected to the thin film  82 , which is placed over and adhered to a portion of the top surface of the chemical pump housing  150 . The thin film  182  includes a flap  184  and, as depicted in  FIG. 9 , the slit  170  is disposed underneath the flap  184 . The second pull tab  178  can be connected to or provided as a release layer provided on a bottom surface of the thin film  182  in the region of the flap  184 . The release layer covers an adhesive (not visible in  FIG. 9 ) on a bottom surface of the thin film  182 . When the second pull tab  178  is pulled, which occurs after the first pull tab  174  has been removed from the slit  170 , the second pull tab  178  disconnects the release layer from the flap  184  and the adhesive disposed on the bottom surface of the flap  184  is exposed. The flap  184  is then moved towards the chemical pump housing  150  to cover the slit  170 . When the thin film  182  covers the slit  170 , the reactor  116  is closed off from ambient and reacts with the selected gas found in the inner chamber  156  and the enclosed volume  32  under the dressing  14 . Reduced pressure is therefore developed in the enclosed volume  32 . 
     With reference to  FIG. 10 , the electrolyte solution  52  can be injected into the substrate  54  or mass of powdered chemicals making up the reducing agent  50  through the chemical pump housing  150  when reduced pressure therapy is ready to be administered. An injection port  192  can be disposed on the chemical pump housing  150  for guiding a user for injecting the needle  94  of the syringe  90  into the substrate  54  or mass of powdered chemicals making up the reducing agent  50 . When reduced pressure is ready to be administered, the user injects the electrolyte solution  52  into the substrate  54  to impregnate the substrate  54  with the electrolyte solution  52  or into the mass of powdered chemicals making up the reducing agent  50 . Once the reducing agent  50  is wetted with the electrolyte solution  52 , the reactor  16  begins to consume the selected gas in the enclosed volume  32  and the inner chamber  156  of the chemical pump housing  150 . After finishing injecting the electrolyte solution  52  into the dressing  14 , the injection port  92  can be covered with the thin film  182  and the flap  184  in a similar manner to the slit  170  shown in  FIG. 9 . Also, the electrolyte solution  52  stored in the flexible chamber  130  shown in  FIG. 6  can deliver the electrolyte solution  52  through the injection port  192  in the chemical pump housing  150  similar to the syringe  90 . 
     Unlike solutions that package a reactor in a hermitically sealed foil packet, the electrolyte solution is shielded from the reducing agent until reduced pressure therapy of the dressing. It will be appreciated that various of the above-disclosed embodiments and other features and functions, or alternatives or varieties thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.