US20180318165A1 - Tissue treatment device and method - Google Patents

Abstract

A controlled pressure device includes a reactor housing element, a reactor, and a cosmetic liquid or cream. The reactor housing element is configured to at least partially define an at least substantially air-tight enclosed volume around a tissue site when fixed in space in relation to the tissue site. The reactor is positioned in the enclosed volume and is configured to react with a selected gas found in air. The reactor consumes the selected gas within the enclosed volume. The cosmetic liquid or cream is also located in the enclosed volume.

Description

• This application claims priority to U.S. Provisional Application Ser. No. 62/248,422 filed on Oct. 30, 2015, the entirety of which is expressly incorporated by reference.
BACKGROUND
• The pores of the skin can become occluded with impurities. Negative pressure has been used to generate a partial vacuum to aid in removing impurities from the pores. Negative pressure is a term used to describe a pressure that is below normal atmospheric pressure. At room temperature and at sea level, a defined volume of air contains molecules moving in random directions, and these moving molecules exert a force that is equal to the normal atmospheric pressure of approximately 760 mmHg (about 1 bar). Negative pressure has been achieved by removing air from an area of interest, for example at a tissue site via a suction pump.
• Devices for the generation of topical negative pressure at the surface of a person's skin have been used for many hundreds of years to treat humans. For example, the cupping technique, which relates to positioning a mouth of a rigid vessel containing hot air on a human's skin, is a well-known technique. Spring powered syringes and suction cups are other mechanical techniques that have been used for generating a partial vacuum on human tissue. In common with cupping, such other mechanical techniques have offered a limited topical negative pressure duration and little or no range of neutral to positive pressures. This is due to design constraints and that the cupping technique and other mechanical techniques are not self-contained and can hinder a user's mobility.
• To enable a more prolonged application of topical negative pressure, powered systems, which include a vacuum generation source such as a pump, have been developed and many examples of such systems are used today for skin treatments and restorative purposes like the temporary removal of wrinkles. Many of these systems, however, are not convenient for users. Such known systems can be large, heavy, noisy, uncomfortable, and not simple for users to apply and initiate a controlled pressure condition. Such known systems also rely on an outside power or vacuum source to create topical negative pressure conditions.
SUMMARY
• In view of the foregoing, a controlled pressure device includes a reactor housing element and a reactor. The reactor housing element is configured to at least partially define an at least substantially air-tight enclosed volume around a tissue site when fixed in space in relation to the tissue site. The reactor is positioned in the enclosed volume and is configured to react with a selected gas found in air. The reactor consumes the selected gas within the enclosed volume.
• Another example of a controlled pressure device can include a reactor housing element and a reactor. The reactor housing element is configured to at least partially define an at least substantially air-tight enclosed volume around a tissue site when fixed in space in relation to the tissue site, and the enclosed volume has a determined volume (DV). The reactor is positioned in the enclosed volume and is configured to react with a selected gas found in air. The reactor consumes the selected gas within the enclosed volume. The reactor is configured having a predetermined scavenging capacity (SC) for the selected gas. The controlled pressure device is configured to have a maximum leakage rate (LR) when affixed to a subject's skin for air entering the enclosed volume. The controlled pressure device is also configured to a minimum wear time (MWT) and is configured according to the following relationship: SC>DV*(% of selected gas in air)+LR*(% of selected gas in air)*MWT.
• In view of the foregoing, method of treating a tissue site includes removing a release layer from a reactor housing element. The method further includes placing the reactor housing element, a reactor and a liquid impermeable—air permeable membrane over the tissue site. The method also includes affixing the reactor housing element with respect to skin around the tissue site to define an at least substantially air-tight enclosed volume around the tissue site.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a schematic cross-sectional view of a controlled pressure device.
• FIG. 2 is a schematic exploded perspective view of a controlled pressure device.
• FIGS. 3 and 4 are schematic depictions of alternative reactor embodiments that can be used with the controlled pressure device shown inFIG. 1.
• FIGS. 5-7 are schematic depictions of powered components that can be used with the controlled pressure device shown inFIG. 1.
• FIGS. 8 and 9 are flow diagrams depicting a method of treating a tissue site.
DETAILED DESCRIPTION
• FIG. 1 depicts a controlledpressure device10 including areactor housing element14 and areactor16. The controlledpressure device10 can be used in conjunction with a cosmetic liquid or cream for tissue treatment. For example, the controlledpressure device10 can include or be used in conjunction with a pad, which can be wetted or impregnated with a cosmetic liquid or cream, and will be hereinafter referred to as acosmetic pad18. The controlledpressure device10 can be positioned at atissue site20 to enhance tissue treatment including, but not limited to, wound healing, reduction of skin wrinkles, and other skin maladies. Thereactor housing element14 is configured to at least partially define an at least substantially air-tight enclosedvolume22 around thetissue site20 when affixed in space in relation to thetissue site20.FIG. 1 depicts thereactor housing element14 in contact with the tissue (e.g., skin) around thetissue site20, however, thereactor housing element14 can be fixed in space in relation to thetissue site20 without being in direct contact with the tissue around thetissue site20. For example, an intermediate membrane or layer, such as a skin contacting element24 (FIG. 2), could be interposed between thereactor housing element14 and the tissue (e.g., skin) around thetissue site20, although thereactor housing element14 is fixed in space in relation to thetissue site20. Thereactor16 positioned in the enclosedvolume22 reacts with a selected gas found in air and consumes the selected gas within the enclosedvolume22. The cosmetic liquid or cream is also located in the enclosedvolume22.
• With reference toFIG. 2, the controlledpressure device10 can includes theskin contacting element24. Theskin contacting element24 includes askin contacting side30 that is adherable to a subject's skin and aninterface side32, which is opposite to the skin contacting side. In the illustrated embodiment, theskin contacting element24 is shown as a separate element from thereactor housing element14. In an alternative arrangement, theskin contacting element24 can be provided as part of thereactor housing element14, e.g., theskin contacting element24 can be integrally formed with thereactor housing element14 or connected with thereactor housing element14 at the manufacturing facility. Theskin contacting element24 can be made from a thin sheet-like membrane, for example using a roll-to-roll process. In the illustrated embodiment, theskin contacting element24 also includesopenings34 extending through theskin contacting element24 from theskin contacting side30 to theinterface side32. Theopenings34 can be located over thetissue site20. In conjunction with askin contacting gasket36, theskin contacting element24 is configured to provide a seal around thetissue site20 to allow for topical negative pressure to be applied at thetissue site20. If desired, theskin contacting element24 can include an opening that is larger than each of theopenings34 depicted inFIG. 2. In this example, theopening34 can be dimensioned to fit around thetissue site20. The opening34 in this example can be similarly shaped to thecosmetic pad18 so that theskin contacting element24 and theskin contacting gasket36 provide a seal around the tissue site20 (FIG. 1) and thecosmetic pad18. If desired, theskin contacting element24 need not include the opening(s)34, and in this example, thecosmetic pad18 can be positioned beneath theskin contacting side30 so as to come in contact with the subject's skin at thetissue site20.
• Both theskin contacting side30 and theinterface side32 are generally flat or planar. In the illustrated embodiment, theinterface side32 is the upper side of theskin contacting element24 and theskin contacting side30 is the lower side of the skin contacting element. Adhesive38 (depicted schematically inFIG. 2) can provided on theskin contacting side30 to allow theskin contacting side30 to adhere to the subject's skin around thetissue site20.
• Theskin contacting gasket36 can be provided on theskin contacting side30 of theskin contacting element24 or simply be positioned between theskin contacting side30 and the subject's skin. Theskin contacting gasket36 can be made from a hydrogel to further promote sealing around thetissue site20 to promote the topical negative pressure at thetissue site20.
• Arelease layer40 can be provided with the controlledpressure device10 to protect theskin contacting side30 of theskin contacting element24. Therelease layer40 can be similar to known release layers and include anupper side42 that is releasable from theskin contacting side30 of theskin contacting element24. Therelease layer40 also includes alower surface44 opposite theupper side42. As mentioned above, thereactor16 reacts with a selected gas found in air and consumes the selected gas within theenclosed volume22. In some embodiments, therelease layer40 can provide an air-tight barrier such that air is precluded from access to thereactor16 until after therelease layer40 is removed from theskin contacting element24. In embodiments where theskin contacting element24 may not be provided, therelease layer40 can cooperate with thereactor housing element14 in a similar manner, and therelease layer40 can provide an air-tight barrier such that air is precluded from access to thereactor16 until after therelease layer40 is removed from thereactor housing element14.
• With reference back toFIG. 1, thereactor housing element14 at least partially defines theenclosed volume22 around thetissue site20 when fixed in space in relation to thetissue site20. With reference to the embodiment depicted inFIG. 2, thereactor housing element14 cooperates with theskin contacting element24 to at least partially define the enclosed volume22 (seeFIG. 1) around thetissue site20, for example, when theskin contacting side30 of theskin contacting element24 is in contact with and adhered to the subject's skin and thereactor housing element14 is affixed to theskin contacting element24. Thereactor housing element14 can be formed with ahood50 and a lowerperipheral section52 that at least partially surrounds thehood50. In the illustrated embodiment, the lowerperipheral section52 entirely surrounds thehood50, which is raised in relation to the lowerperipheral section52 so as to define theenclosed volume22 around thetissue site20. Thereactor housing element14 can also be formed without thehood50, i.e., thereactor housing element14 could initially be planar. Similar to theskin contacting element24, thereactor housing element14 can be made from a thin sheet-like membrane, for example using a roll-to-roll process. Thereactor housing element14 can be made from a flexible material that is similar to or the same flexibility as theskin contacting element24, which allows the controlledpressure device10 to conform to the skin around thetissue site20. When thereactor housing element14 is affixed to theskin contacting element24, thereactor16 is located between thereactor housing element14 and thecosmetic pad18 and theskin contacting element24. Since thereactor housing element14 is made from a flexible material in this example, the section of thereactor housing element14 that is not in contact with theskin contacting element24 is raised or offset from thetissue site20 so as to form thehood50.
• Thereactor housing element14 can be made from a material that is air impermeable so that air is precluded or greatly inhibited from entering into theenclosed volume22 as thereactor16 consumes a selected gas within the enclosed volume thus reducing gas pressure within the enclosed volume. Thereactor housing element14 could also be made from materials that are impervious to particular gasses (e.g., oxygen) and pervious to other gases (e.g., nitrogen). Thereactor housing element14 can be formed of a material that is at least partially gas permeable for selected gasses (e.g., nitrogen gas permeable) to exhaust the selected gas from thetissue site20 to atmosphere. Thereactor housing element14 includes alower surface56. An adhesive58 (depicted schematically inFIG. 2) can be applied to thelower surface56. With reference toFIG. 1, thelower surface56 contacts the skin around thetissue site20 and the adhesive58 adheres thereactor housing element14 to the skin around thetissue site20. A reactorhousing element gasket60, which can be a hydrogel gasket similar to theskin contacting gasket36 described above, can be provided between thelower surface56 of thereactor housing element14 and the skin to further seal between thereactor housing element14 and the skin to preclude air migration between the interface between thelower surface56 the skin.
• With reference toFIG. 2, thereactor housing element14 can affix to theinterface side32 of theskin contacting element24 providing a substantially air-tight seal between thereactor housing element14 and theskin contacting element24. The adhesive58 applied to thelower surface56 can affix thereactor housing element14 to theskin contacting element24. The reactorhousing element gasket60 can be provided between thelower surface56 of thereactor housing element14 and theinterface side32 of theskin contacting element24 to further seal between thereactor housing element14 and theskin contacting element24 to preclude air migration between the interface between thelower surface56 of thereactor housing element14 and theinterface side32 of theskin contacting element24.
• Thereactor16 is positioned in theenclosed volume22 and is configured to react with one of more selected gases (e.g., nitrogen, oxygen, carbon dioxide) found in air to consume the selected gas within theenclosed volume22, which can reduce gas pressure within theenclosed volume22. The reduction in gas pressure within theenclosed volume22 can result in a partial vacuum being formed in theenclosed volume22, which can result in a downward force (in the direction of arrow70) being applied to thehood50 of thereactor housing element14. Thereactor housing element14 can be configured such that the downward force (in the direction of arrow70) on the hood50 (or the top of the reactor housing element14) results in an outward force (normal to the direction of arrow70) on the lowerperipheral section52. Since thereactor housing element14 is affixed to theskin contacting element24, which is adhered to the subject's skin, or directly to the skin (seeFIG. 1) the outward force in the direction normal to arrow70 can result in small strains and stresses being applied to the patient's skin around thetissue site20. These strains and stresses being applied to the patient's skin can be beneficial for the introduction of the cosmetic liquid or cream impregnated within thecosmetic pad18 as well as providing a massaging effect of the skin. Where thereactor housing element14 is made from a relatively more rigid material with respect to theskin contacting element24, for example,flexible regions74 can be provided in the lowerperipheral section52 to facilitate outward movement of thereactor housing element14 with respect to thetissue site20 to allow for the small strains and stresses to be applied to the subject's skin at thetissue site20.
• Thereactor16 is positioned in theenclosed volume22 and is configured to react with the selected gas (e.g., nitrogen, oxygen, carbon dioxide) found in air. As thereactor16 consumes the selected gas within theenclosed volume22, the gas pressure within theenclosed volume22 is reduced. For example, where thereactor16 consumes oxygen, there can be an approximate 20% reduction from atmospheric pressure in theenclosed volume22. An example of areactor16 that can be used in the controlled pressure device is described in US 2014/0109890 A1, which is incorporated by reference herein. US 2014/0109890 A1 describes an oxygen based heater; however, the oxygen based heater described in US 2014/0109890 A1 can be used as thereactor16 to consume oxygen within theenclosed volume22 thus producing a partial vacuum within theenclosed volume22. In this example, thereactor16 includes a reducing agent, a binding agent on areactor substrate80 and an electrolyte solution, which can be provided in an electrolyte impregnatedpad82. The reducing agent on thereactor substrate80 can be zinc, aluminum, or iron, for example.
• As mentioned above, therelease layer40 can operate as an air-tight barrier such that the selected gas (e.g., nitrogen, oxygen, carbon dioxide) is precluded from access to thereactor16 until after the air-tight barrier, which in this instance is therelease layer40, is removed from the controlledpressure device10. Alternatively, the controlledpressure device10 can include a package, which is shown inFIG. 2 as including anupper layer94 and alower layer96. Theupper layer94 affixes to thelower layer96 enclosing thereactor substrate80 in between theupper layer94 and thelower layer96 so as to provide an air-tight seal so that the selected gas is precluded from access to thereactor16. In this example including the package, theupper layer94 or thelower layer96 can operate as an air tight barrier in that removal of theupper layer94 from thelower layer96, or vice versa, allows the selected gas access to thereactor16 so that the selected gas can be consumed by thereactor16. Alternatively, at least one of the layers (thelower layer96 in the illustrated embodiment) can includeopenings98 and aseal layer102 can be affixed in an air-tight manner to thelower layer96 covering theopenings98. Removal of theseal layer102 from thelower layer96 exposes thereactor16 to the selected gas, which allows the reactor to consume the selected gas within theenclosed volume22. The surface area of theopenings98 can be appropriately sized to control the flow of the selected gas through the openings to sustain the chemical reaction of thereactor16 to the desirable time limit for maintaining topical negative pressure on thetissue site20 for the desired duration. Moreover,multiple seal layers102 can be provided so that removal of one or a selected few of the seal layers (while other seal layers are still affixed to the lower layer96) can also be provided to limit the flow of the selected gas toward thereactor16. Additionally, to further control the pressure within the enclosed volume, the controlledpressure device10 can include apressure relief valve106 on thereactor housing element14. Thepressure relief valve106 can allow for selected communication between theenclosed volume22 and ambient. Thepressure relief valve106 can be operated when a predetermined pressure differential exists between theenclosed volume22 and ambient. Moreover, thepressure relief valve106 can be configured to open when the temperature within the enclosed volume exceeds a desired predetermined temperature.
• To also further control the pressure within theenclosed volume22, the controlledpressure device10 can be configured to allow an operator to change the size of theenclosed volume22 while thereactor16 consumes the selected gas in the enclosed volume, thus varying the gas pressure within theenclosed volume22. For example, atab110 can be affixed to thereactor housing element14, and the operator can pull thetab110 to move the reactor housing element away from thetissue site20. InFIG. 2, thetab110 is affixed to thehood50. When theenclosed volume22 is under negative pressure, thehood50 will tend to travel toward thetissue site20. By pulling on thetab110, thehood50 can be moved away from thetissue site20 and air can enter theenclosed volume22, for example by leaking past thegasket36 or a small pre-configured leakage path can be provided. Air entering theenclosed volume22 can increase the pressure within theenclosed volume22 until the selected gas (e.g., oxygen) is consumed by thereactor16. Such a configuration can allow for a cycling of pressure in theenclosed volume22.
• The controlledpressure device10 can also be packaged such that thereactor housing element14 and thereactor16 are packaged separately from theskin contacting element24, for example. In such an embodiment, a reactor housingelement release layer120 can be provided. Thereactor housing element14release layer120 can be similar to therelease layer40 having anupper side122 that is releasable from thelower surface56 of thereactor housing element14. The reactor housingelement release layer120 further includes alower surface124 that is opposite to theupper side122. The reactor housingelement release layer120 can also be affixed to thelower layer96, so that removal of the reactor housingelement release layer120 from thereactor housing element14 results in removal of thelower layer96 from theupper layer94, thus exposing thereactor16 to air. Alternatively, the reactor housingelement release layer120 can be affixed to theseal layer102 such that removal of the reactor housingelement release layer120 from thereactor housing element14 results in removal of theseal layer102 from thelower layer96, thus exposing thereactor16 to air via theopenings98 provided in thelower layer96.
• Where the controlledpressure device10 is packaged where thereactor housing element14 and thereactor16 are separate from theskin contacting element24, an upper skin contacting element release layer (not shown) can be provided. The upper skin contacting element release layer can be similar to therelease layer40. Alternatively, no upper skin contacting element release layer need be provided.
• The controlledpressure device10 further includes a liquid impermeable-airpermeable membrane150 interposed between thereactor16 and the cosmetic liquid or cream, which is impregnated in thecosmetic pad18 in the illustrated embodiment. The size (area) of the liquid impermeable-airpermeable membrane150 can depend on the location of the liquid impermeable-airpermeable membrane150 within the controlledpressure device10. If the cosmetic liquid or cream were to come in contact with thereactor16, the chemical reaction of thereactor16 when coming in contact with the selected gas may be detrimentally impacted. As such, the liquid impermeable-airpermeable membrane150 allows air flow within theenclosed volume22 while precluding the cosmetic liquid or cream from coming into contact with thereactor16.
• The liquid impermeable-airpermeable membrane150 can be located in different locations on the controlledpressure device10. In one example depicted inFIG. 2, the liquid impermeable-airpermeable membrane150 can be located between thereactor substrate80 and thelower layer96 making up the air-tight package for thereactor16. So, once the lower layer96 (or the seal layer102) is removed, air can gain access to thereactor16, but the cosmetic liquid or cream would be precluded from traveling through the liquid impermeable-airpermeable membrane150. In another example, the liquid impermeable-airpermeable membrane150 can be located between the lower layer96 (or the seal layer102) making up the air-tight package for thereactor16 and the cosmetic liquid or cream, which can be impregnated in thecosmetic pad18. More generally, and as depicted inFIG. 1, the liquid impermeable-airpermeable membrane150 can be located between thereactor16 and the cosmetic liquid or cream, which would be impregnated in thecosmetic pad18. As depicted inFIG. 1, the liquid impermeable-airpermeable membrane150 can be connected with thereactor housing element14 and preclude the cosmetic liquid or cream from passing through the liquid impermeable-airpermeable membrane150 while allowing air to travel through the liquid impermeable-airpermeable membrane150 so that the selected gas can be removed from the enclosedvolume22. If desired, the liquid impermeable-airpermeable membrane150 could surround thereactor16 and preclude the cosmetic liquid or cream from passing through the liquid impermeable-airpermeable membrane150 while allowing air to travel through the liquid impermeable-airpermeable membrane150.
• In an embodiment where thereactor housing element14 and thereactor16 are packaged separately from theskin contacting element24, therelease layer40 can be removed from theskin contacting element24. Theskin contacting element24 can be pressed against a subject's skin around thetissue site20 and adhesive38 on the skin contacting side of theskin contacting element24 can adhere theskin contacting element24 to the subject's skin. Theskin contacting gasket36 can surround thetissue site20 to promote an air-tight seal between theskin contacting element24 and the subject's skin around thetissue site20. The cosmetic liquid or cream, which is located within thecosmetic pad18 in the illustrated embodiment, is then brought into contact with thetissue site20 by traveling through theopenings34.
• The reactor housingelement release layer120 can be removed from thereactor housing element14. Removal of the reactor housingelement release layer120 from thereactor housing element14 can expose thereactor16 to air by removal of thelower layer96, theseal layer102, or the reactor housingelement release layer120 may be affixed in an air-tight manner to thereactor housing element14 so that air is precluded from access to thereactor16 until after the reactor housingelement release layer120 is removed from thereactor housing element14. After removal of the reactor housingelement release layer120 from thereactor housing element14, thelower surface56 of thereactor housing element14 can be brought in contact with anupper surface152 of the liquid impermeable-airpermeable membrane150, which can have itslower surface154 affixed to theinterface side32 of theskin contacting element24. Alternatively, where the liquid impermeable-airpermeable membrane150 is positioned between thereactor substrate80 and thelower layer96, thelower surface56 of thereactor housing element14 can be brought in contact with theinterface side32 of theskin contacting element24. When thereactor housing element14 is brought into contact with the liquid impermeable-airpermeable membrane150 and/or theskin contacting element24, thereactor16 consumes the selected gas found within theenclosed volume22. A chemical reaction occurs where heat can be generated, and a pressure reduction with respect to atmospheric pressure occurs by consumption of the selected gas. Thereactor16 can heat theenclosed volume22 above ambient, which can provide a therapeutic effect for use with some cosmetic liquids or creams. In addition, suction can be applied to the tissue site thus stretching the subject's skin at the tissue site, which can also have a therapeutic effect with certain cosmetic liquids or creams. Moreover, the application of topical negative pressure at a particular tissue site can also have a therapeutic effect.
• The controlledpressure device10 can be designed with certain parameters. As an example, assuming thetissue site20 of about 10 cm×20 cm and an offset of the hood50 (or the top of the reactor housing element14) of about 2.5 cm from thetissue site20 results in theenclosed volume22 of 500 mL. Assuming that the cosmetic liquid or cream and the solid components of thecosmetic pad18 in addition to thereactor16 and any other solid components (e.g., the liquid impermeable-air permeable membrane150) within theenclosed volume22 account for 100 mL within theenclosed volume22, this leaves 400 mL air in the enclosed volume. 400 mL of air results in about 320 mL of nitrogen and 80 mL of oxygen within theenclosed volume22 prior to the application of a partial vacuum resulting from thereactor16 consuming a selected gas in the air within theenclosed volume22. One gram (1 g) of zinc (Zn) will consume about 170 mL at standard temperature and pressure (STP) of oxygen (02), which is the amount of oxygen in about 850 mL (STP) of normal dry air. Although theskin contacting gasket36 and the reactorhousing element gasket60 can be provided, there will likely be leakage of ambient air into theenclosed volume22 past thegaskets36,60 and possibly diffusion through thereactor housing element14 and theskin contacting element24. For the purposes of this disclosure, both leakage past interfaces (e.g., leakage around the skin contacting gasket36) and diffusion (e.g., diffusion through the reactor housing element14) will be referred to as leakage. Thegaskets36,60, theskin contacting element24 andreactor housing element14 are configured to have a maximum leakage rate of air into theenclosed volume22 from ambient. For example, a maximum leakage rate of 1 mL (STP)/hour of air into the enclosed volume from ambient results in 0.2 mL (STP) of oxygen/hour. Since 1 g of zinc consumes 170 mL of oxygen (STP), 1 g of zinc provides an adequate amount of a reducing agent to result in a 20% reduction from normal atmospheric pressure within theenclosed volume22 for an extended period of time, e.g., well over 72 hours. The controlledpressure device10 will likely be worn for a much shorter period of time and thetissue site20 being treated may be much smaller than 10 cm×20 cm. It can be seen that a verysmall reactor16, e.g., one able to accommodate less than 1 g of zinc, can be used in the controlledpressure device10.
• In view of the foregoing, the controlledpressure device10 can be configured as follows. Thereactor16 can be configured to have a predetermined scavenging capacity (“SC”), which relates to the volume of the selected gas that thereactor16 is configured to consume. For example, as mentioned above 1 g of zinc will consume about 170 mL of oxygen (STP), so the scavenging capacity would be 170 mL. Theenclosed volume22 can have a determined volume (“DV”) based on the area of thetissue site20, the size of thereactor housing element14, the offset of the hood50 (or top of the reactor housing element14) from thetissue site20, taking into account the cosmetic liquid or cream and the solid components of thecosmetic pad18 in addition to thereactor16 and any other solid components within theenclosed volume22. For example, the determined volume of 400 mL was discussed above. Also, the controlledpressure device10 can be configured to have a maximum leakage rate (LR) for air entering theenclosed volume22. In addition, the controlledpressure device10 can be configured to have a minimum wear time (“MWT”), which relates to the minimum amount of time that the controlledpressure device10 is configured to be worn. Assuming that it is desirable to have thereactor16 consume, or scavenge, the selected gas for the entire minimum wear time, the controlled pressure device can be configured in view of the following relationship:
• 
  SC>DV*(% of selected gas in air)+LR*(% of selected gas in air)*MWT.
• The scavenging capacity can be determined to provide a relativelysmall reactor16 in relation to thereactor housing element14 and thetissue site20 to be treated. The determined volume can be determined to provide a relativelysmall reactor16 andreactor housing element14 in view thetissue site20 to be treated. The maximum leakage rate for air entering theenclosed volume22 should be reduced as much as is practical; however, there may be some circumstances in which a predetermined amount of leakage is desirable, for example where cycling of pressure within theenclosed volume22 is desired. For example, the maximum leakage rate for air entering theenclosed volume22 can be less than 10 mL/hour, and preferably less than 1 or 2 mL/hr. The minimum wear time can be determined based on the desired amount of time the topical negative pressure is to be applied to thetissue site20. It may be desirable to include a safety factor (e.g., a multiplier on the right side of the relationship above) to accommodate for manufacturing tolerances, differences among tissues sites and subjects placing the controlledpressure device10 on thetissue site20.
• As thereactor16 consumes the selected gas found in air within theenclosed volume22, an exothermic reaction occurs such that there is an increase in temperature of thereactor16. As such, thereactor16 can operate as a heater to heat the cosmetic liquid or cream impregnated in thecosmetic pad18. This can change the viscosity of the cosmetic liquid or cream, which can facilitate entry of the cosmetic liquid or cream into skin pores.
• Thereactor housing element14 could also be provided with aremovable section160 that when removed could provide ambient air access to thereactor16 or an additional reactor located beneath thereactor housing element14. For example, theremovable section160 can be affixed to theupper layer94 of the package in which thereactor substrate80 is located. Removal of theremovable section160 can result in removal of at least a portion of theupper layer94 thus exposing thereactor substrate80 to ambient air, which would result in an exothermic reaction. Alternatively, an additional reactor could be located beneath thereactor housing element14 and removal of theremovable section160 can result in removal of at least a portion of the package (similar to the package made up of theupper layer94 and the lower layer96) thus exposing the additional reactor to ambient air. The additional reactor can also heat the gas in theenclosed volume22, which can heat thetissue site20.
• Different types of reactors could be used to provide topical negative pressure inside theenclosed volume22 of the controlledpressure device10.FIG. 3 depicts multiple reactor substrates or multiple regions on the same reactor substrate, which are depicted asreactor elements80a,80band80ceach having different chemical properties and/or characteristics. For example, thefirst reactor element80acan be configured to begin consuming oxygen after being exposed to oxygen for a very short (first) period of time t1, e.g., nearly instantaneously. Thesecond reactor element80bcan be configured to begin consuming oxygen after being exposed to oxygen for a longer (second) period of time t2, and thethird reactor element80ccan be configured to begin consuming oxygen after being exposed to oxygen for an even longer (third) period of time. Alternatively, thesecond reactor element80bcan be configured with a delayed reaction time to begin consuming oxygen after thefirst reactor element80ahas been exhausted and no longer consumes oxygen. Similarly, thethird reactor element80ccan be configured with a delayed reaction time to begin consuming oxygen after thefirst reactor element80aand thesecond reactor element80bhave both been exhausted and no longer consume oxygen. Such a configuration can allow for a cycling of pressure in theenclosed volume22.
• In lieu of thereactor16 made up of thereactor substrate80, thereactor16 may be one or any combination of a zinc-based chemical pump, electro-chemical pumps, vacuum-on-demand devices (referred to herein as VOD), electrolyzers, pressure-reducing solid state devices, oxygen absorbing iron packets, or getters of zirconium titanium, vanadium iron, lithium, lithium metal, magnesium, calcium, lithium barium combinations, zinc-air battery, zinc-air battery components or other materials highly reactive with the selected gases, for example, nitrogen, carbon dioxide and oxygen gases found in skin tissue environments.
• FIG. 4 depicts anotherreactor226 that can be used in place of thereactor16 shown inFIG. 1. WO 2015/054040 A1, which is incorporated by reference, describes an electrochemical cell that is adapted to consume gases, i.e., air or its gaseous non-noble constituents, within an enclosure via an electrochemical reaction. This consumption of gas within a sealed enclosure forms a partial vacuum. The controlledpressure device10 can include such areactor226 having anelectrochemical cell228 that lowers the pressure within theenclosed volume22 through an electrochemical reaction that takes place when a voltage is applied to theelectrochemical cell228 by a power source230 (depicted schematically inFIG. 4). Operation ofelectrochemical cell228 in this example can also be achieved by controlling the current supplied to theelectrochemical cell228 by thepower source230, for example by providing aswitch232 that can be operated by the user. Thepower source230 can be located in theenclosed volume22 or be provided outside the controlled pressure device10 (e.g. on the reactor housing element14). Theswitch232 can be provided outside the controlled pressure device10 (e.g. on the reactor housing element14).
• In an example where the reactor is a VOD device, a VOD is a solid state electrochemical cell, which when charged with a low voltage, produces a highly reactive material that captures gases present in the atmosphere and when sealed in an air tight system can form a partial vacuum. In a VOD device, metal is deposited to grow dendrites as a voltage is applied across electrodes of the VOD device and lithium salt electrolyte, charging the VOD device. Similar to charging a battery, electrons are moved from layer to layer to form metallic lithium.
• In an example where the reactor is a getter, a getter, as known in the art, is a deposit of reactor material that is used for initiating and maintaining a partial vacuum. When gas molecules strike the getter material, particular gas molecules (i.e., those of the selected gas) combine with the getter chemically or by adsorption. Thus the getter removes the selected gas from the evacuated space until the active material is exhausted.
• A reactor having a self-regulating oxygen getter powered by zinc-air battery technology may be used in lieu of the above-describedreactor16 made up of thereactor substrate80. Zinc-air batteries can react to control or reduce the oxygen levels in sealed site and thus self-regulate a reduced pressure of approximately 0.8 bars. If the zinc-air battery components are configured as a working zinc-air battery, the battery voltage will drop when the oxygen has been depleted and the desired partial vacuum pressure will have been achieved. This drop in voltage may be used to indicate that the desired partial vacuum has been achieved. For example, a 675 size hearing aid zinc-air battery is rated at 620 mAh, occupies 0.5 mL volume, and weighs 1.9 g. A675 zinc-air battery can remove more than 150 times its volume of oxygen.
• Thecosmetic pad18 can be made from a blend of polyester and cellulose fibers, polypropylene fibers, or other suitable non-woven polymeric material. The cosmetic liquid or cream can include at least one of a moisturizer, dimethylaminoethanol (DMAE), Acetyl hexapeptide-8, Acetyl hexapeptide-3, retinol, ubiquinone, dithiolane-3-pentanic acid, alpha-hydroxy acid, alpha lipoic acid, salicylic acid, hydrocortisone, topical botulinum cream, and hyaluronic acid. Thecosmetic pad18 can includetop surface180 and abottom surface182, which is opposite thetop surface180. Thebottom surface182 can be undulated havinghills184 andvalleys186, which can allow thecosmetic pad18 to act as a skin massaging element. Anadditional membrane188 could be provided and located beneath thecosmetic pad18 to act as the skin massaging element. Thisadditional membrane188 would also be positioned adjacent to thetissue site20. Thisadditional membrane188 could also include an undulated bottom surface, similar to thebottom surface182 havinghills184 andvalleys186. Thisadditional membrane188 would also include openings to allow the cosmetic liquid or cream to pass through the openings to thetissue site20. When a partial vacuum is provided in theenclosed volume22, the skin can be drawn towards the undulated surface and the skin can conform to thehills184 andvalleys186. Accordingly, small strains and stresses can applied to the patient's skin at thetissue site20 providing a massaging effect.
• The controlledpressure device10 can also include additional powered components, which is shown as apowered component240 that is schematically depicted inFIG. 2. Eachpowered component240, which are described later with reference toFIGS. 5-7, can be electrically connected with a power source242 (depicted schematically inFIG. 2) which, for example, can be a zinc-air battery exposed to ambient or a zinc MnO2 battery, electrically connected with thepowered component240. When using a zinc-air battery as thepower source242, thepower source242 would be located outside of theenclosed volume22 or a section of thereactor housing element14 or theskin contacting element24 could be removable to allow ambient air to contact the zinc-air battery.
• FIG. 5 depicts aheater250, which is one example of apowered component240 that can be used in the controlledpressure device10, electrically connected with thepower source242. Theheater250 can be a thin film heater or thin film nano wire heater. Theheater250 can heat the cosmetic liquid or cream impregnated in thecosmetic pad18. Theheater250 can be positioned adjacent to thecosmetic pad18. Aswitch252 can be provided to control power to theheater250. Theheater250 can also heat the gas in theenclosed volume22, which can heat thetissue site20.
• FIG. 6 depicts afirst electrode260 and asecond electrode262 electrically connected with thepower source242. The electrodes are another example of apowered component240 that can be used in the controlledpressure device10. Theswitch252 can be provided to control power to theelectrodes260,262. Thefirst electrode260 can be positioned on a first side of thetissue site20 and in contact with the skin, and thesecond electrode262 can be positioned on a second, opposite, side of thetissue site20 and in contact with the skin. Theelectrodes260,262 can be used to provide electrical stimulation to thetissue site20.
• FIG. 7 depicts alight source280, which is another example of apowered component240 that can be used in the controlledpressure device10. Thelight source280 can include a plurality ofLEDs282 mounted on aflexible substrate284. TheLEDs282 are electrically connected with thepower source242. Theflexible substrate284 can be placed adjacent to theskin contacting element24, which can includelarger openings34, which can allow light to pass for phototherapy.
• FIG. 8 depicts a method of treating tissue using negative pressure. Although theFIG. 8 shows a specific order of method steps, the order of the steps may differ from what is depicted. Also two or more steps may be performed concurrently or with partial concurrence. The method will be described with reference to the controlledpressure device10 depicted inFIGS. 1 and 2, however, the method can be practiced with other devices.
• At300, the reactor housingelement release layer120 is removed from thereactor housing element14. Removal of the reactor housingelement release layer120 from thereactor housing element14 can allow air to contact thereactor16, which can begin the reaction in which oxygen (or another selected gas in air) is being consumed by thereactor16. At302, thereactor housing element14, thereactor16 and the liquid impermeable—airpermeable membrane150 are placed over thetissue site20. At304, thereactor housing element14 is affixed with respect to the skin around thetissue site20 to define an at least substantially air-tightenclosed volume22 around the tissue site. Thereactor16 can consume the selected gas (e.g., oxygen) from the enclosedvolume22 thus reducing the gas pressure in theenclosed volume22.
• FIG. 9 depicts other steps in a method of treating tissue using negative pressure. For example, the method may include, at310, placing a cosmetic liquid or cream on thetissue site20. The cosmetic liquid or cream may be placed on thetissue site20 prior to placing thereactor housing element14, thereactor16 and the liquid impermeable—airpermeable membrane150 over thetissue site20, which occurs atstep302.
• The method of treating tissue using negative pressure may also include, at312, placing apad18 impregnated or wetted with a cosmetic liquid or cream over thetissue site20. Thepad18 can be connected with thereactor housing element14 in such a manner that thepad18 is placed on thetissue site20 while placing thereactor housing element14, thereactor16 and the liquid impermeable—airpermeable membrane150 over thetissue site20.
• The method of treating tissue using negative pressure may also include, at314, removing therelease layer40 from theskin contacting element24, and, at316, placing theskin contacting element24 over or around thetissue site20. Theskin contacting element24 can be placed over or around thetissue site20 prior to placing thereactor housing element14, thereactor16 and the liquid impermeable—airpermeable membrane150 over thetissue site20, which occurs atstep302. As such, affixing thereactor housing element14 with respect to skin around the tissue site, which occurs atstep304, can further include affixing thereactor housing element14 to theskin contacting element24, at318. The method may also include affixing theskin contacting element24 to the skin around thetissue site20, at320.
• It will be appreciated that various of the above-disclosed controlled pressure device 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.

Claims (33)

1. A controlled pressure device for tissue treatment, the device comprising:

a reactor housing element configured to at least partially define an at least substantially air-tight enclosed volume around a tissue site when fixed in space in relation to the tissue site; and

a reactor positioned in the enclosed volume and configured to react with a selected gas found in air, wherein the reactor consumes the selected gas within the enclosed volume.

2. The controlled pressure device ofclaim 1, further comprising a cosmetic liquid or cream located in the enclosed volume.

3. The controlled pressure device ofclaim 2, wherein the cosmetic liquid or cream includes at least one of a moisturizer, dimethylaminoethanol (DMAE), Acetyl hexapeptide-8, Acetyl hexapeptide-3, retinol, ubiquinone, dithiolane-3-pentanic acid, alpha-hydroxy acid, alpha lipoic acid, salicylic acid, hydrocortisone, topical botulinum cream, and hyaluronic acid.

4. The controlled pressure device ofclaim 2, further comprising a pad impregnated with the cosmetic liquid or cream.

5. The controlled pressure device ofclaim 1, wherein the reactor includes a reactor substrate, a reducing agent, a binder, and an electrolyte solution.

6. The controlled pressure device ofclaim 1, further comprising a release layer adhered to a lower surface of the reactor housing element, wherein the release layer provides an air-tight barrier such that air is precluded from access to the reactor until after the release layer is removed from the reactor housing element.

7. (canceled)

8. The controlled pressure device ofclaim 1, further comprising a package including a plurality of air-tight barriers selectively removable from the package, wherein the reactor is positioned within the package and the selected gas is precluded from access to the reactor until after at least one of the plurality of air-tight barriers is removed from the package.

9. The controlled pressure device ofclaim 1, wherein the reactor includes a plurality of reactor elements is-configured to cycle gas pressure in the enclosed volume, wherein the plurality of reactors includes a first reactor element configured to begin consuming oxygen after being exposed to oxygen for a first period of time and a second reactor element configured to begin consuming oxygen after being exposed to oxygen for a second period of time, which is greater than the first period of time.

10. (canceled)

11. (canceled)

12. (canceled)

13. The controlled pressure device ofclaim 1, further comprising a skin contacting element including a skin contacting side for contacting a subject's skin, wherein the skin contacting element includes an opening extending through the skin contacting element from the skin contacting side to an interface side, which is opposite to the skin contacting side.

14. The controlled pressure device ofclaim 13, wherein the reactor housing element affixes to the interface side of the skin contacting element providing a substantially air-tight seal between the reactor housing element and the skin contacting element.

15. The controlled pressure device ofclaim 14, further comprising an air-tight barrier selectively removable from the reactor housing element, wherein the reactor is positioned between the reactor housing element and the air-tight barrier and the selected gas is precluded from access to the reactor until after the air-tight barrier is removed from the reactor housing element.

16. (canceled)

17. The controlled pressure device ofclaim 1, wherein the reactor housing element includes a hood and a lower peripheral section at least partially surrounding the hood, the reactor housing element being configured such that a downward force on the hood results in an outward force on the lower peripheral section.

18. The controlled pressure device ofclaim 1, further comprising a liquid impermeable—air permeable membrane interposed between the reactor and the tissue site when the reactor housing element is fixed in space in relation to the tissue site.

19. The controlled pressure device ofclaim 1, further comprising a cosmetic liquid or cream located in the enclosed volume and a liquid impermeable—air permeable membrane interposed between the reactor and the cosmetic liquid or cream.

20. The controlled pressure device ofclaim 1, further comprising a pressure relief valve on the reactor housing element, wherein the pressure relief valve allows for selective communication between the enclosed volume and ambient.

21. The controlled pressure device ofclaim 1, wherein the controlled pressure device is configured to allow an operator to change the size of the enclosed volume while the reactor consumes the selected gas in the enclosed volume.

22. (canceled)

23. (canceled)

24. The controlled pressure device ofclaim 1, wherein the reactor is configured having a predetermined scavenging capacity (SC) for the selected gas, wherein the enclosed volume has a determined volume (DV), the controlled pressure device is configured to have a maximum leakage rate (LR) for air entering the enclosed volume, and the controlled pressure device is configured to a minimum wear time (MWT) wherein:

SC>DV*(% of selected gas in air)+LR*(% of selected gas in air)*MWT.

25. The controlled pressure device ofclaim 1, wherein the reactor is one or any combination of a zinc-based chemical pump, an electro-chemical pump, a vacuum-on-demand device, an electrolyzer, a pressure-reducing solid state device, an oxygen absorbing zinc or iron packet, a zinc-air battery, a zinc-air battery component and a getter of zirconium titanium, vanadium iron, lithium, lithium metal, magnesium, calcium, lithium barium combinations.

26. The controlled pressure device ofclaim 1, wherein the reactor is configured to consume ambient oxygen to heat cosmetic liquid or cream in the enclosed volume.

27. The controlled pressure device ofclaim 1, wherein the reactor is configured to consume oxygen within the enclosed volume to reduce gas pressure within the enclosed volume, and the controlled pressure device further comprising an additional reactor configured to consume ambient oxygen to heat cosmetic liquid or cream in the enclosed volume.

28. (canceled)

29. (canceled)

30. The controlled pressure device ofclaim 1, further comprising a skin massaging element positioned in the enclosed volume, wherein the skin massaging element is positioned adjacent to the tissue site when the skin contacting side of the skin contacting element is in contact with a subject's skin, wherein the skin massaging element includes an undulated bottom surface.

31. (canceled)

32. The controlled pressure device ofclaim 30, wherein the skin massaging element is a membrane including openings through which cosmetic liquid or cream passes.

33-72. (canceled)

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