Abstract:
A portable system for subatmospheric pressure therapy in connection with healing a surgical wound, including a wound dressing dimensioned for positioning relative to a wound bed of a subject and a subatmospheric pressure mechanism dimensioned to be carried or worn by the subject. The subatmospheric pressure mechanism includes a housing having a control unit adapted to draw a vacuum and a canister associated with the housing. The canister has a collection bag disposed therein, which is in fluid communication with the wound dressing to receive exudates from the wound bed. The collection bag is adapted to expand upon receipt of the fluids and has means to release gas from within the collection bag in connection with operation of the control unit. With this arrangement, the canister is attitude independent, i.e., the canister may be positioned on edge, on its side or on its end etc. while still maintaining operation of the control unit. The collection bag may include a hydrophobic vent or material for releasing the gases. In another embodiment, the collection bag comprises a gas permeable material. The collection bag may include one of pleats or bellows.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present disclosure relates to treating an open wound, and, more specifically, relates to a sub-atmospheric wound therapy system including a portable container adapted to maintain the operation of the system regardless of the orientation or positioning of the container. 
         [0003]    2. Background of Related Art 
         [0004]    Wound closure involves the migration of epithelial and subcutaneous tissue adjacent the wound towards the center and away from the base of the wound until the wound closes. Unfortunately, closure is difficult with large wounds, chronic wounds or wounds that have become infected. In such wounds, a zone of stasis (i.e. an area in which localized swelling of tissue restricts the flow of blood to the tissues) forms near the surface of the wound. Without sufficient blood flow, the epithelial and subcutaneous tissues surrounding the wound not only receive diminished oxygen and nutrients, but, are also less able to successfully fight microbial infection and, thus, are less able to close the wound naturally. Such wounds have presented difficulties to medical personnel for many years. 
         [0005]    Negative pressure therapy also known as suction or vacuum therapy has been used in treating and healing wounds. Application of negative pressure, e.g. reduced or subatmospheric pressure, to a localized reservoir over a wound has been found to assist in closing the wound by promoting blood flow to the area, stimulating the formation of granulation tissue, and encouraging the migration of healthy tissue over the wound. Negative pressure may also inhibit bacterial growth by drawing fluids from the wound such as exudates, which may tend to harbor bacteria. This technique has proven particularly effective for chronic or healing-resistant wounds, and is also used for other purposes such as post-operative wound care. 
         [0006]    Generally, negative pressure therapy provides for a wound to be covered to facilitate suction at the wound area. A conduit is introduced through the wound covering to provide fluid communication to an external vacuum source. Atmospheric gas, wound exudates, or other fluids may thus be drawn from the reservoir through the fluid conduit to stimulate healing of the wound. Exudates drawn from the reservoir may be deposited in a collection canister or container. 
         [0007]    The systems generally require that the container is maintained in a standing or upright position such that the fluid receiving reservoir within the respective unit may be vented and continue to receive fluid from the patient until the reservoir is full. Accidental tipping or tilting of the bag and/or container may cause the suction to/from the unit to be to be shut-off prior to the fluid receiving reservoir completely filling. This problem is further exaggerated in portable units which may be worn or carried by the subject. 
       SUMMARY 
       [0008]    A portable system for subatmospheric pressure therapy in connection with healing a surgical wound includes a wound dressing dimensioned for positioning relative to a wound bed of a subject and a subatmospheric pressure mechanism dimensioned to be carried or worn by the subject. The subatmospheric pressure mechanism includes a housing having a control unit adapted to draw a vacuum and a canister associated with the housing. The canister has a collection bag disposed therein, which is in fluid communication with the wound dressing to receive exudates from the wound bed. The collection bag is adapted to expand upon receipt of the fluids and has means to release gas from within the collection bag in connection with operation of the control unit. With this arrangement, the canister is attitude independent, i.e., the canister may be positioned on edge, on its side or on its end etc. while still maintaining operation of the control unit. The collection bag may include a hydrophobic vent or material for releasing the gases. In another embodiment, the collection bag comprises a gas permeable material. The collection bag may include one of pleats or bellows. 
         [0009]    In another embodiment, the portable system for subatmospheric pressure therapy in connection with healing a surgical wound includes a wound dressing dimensioned for positioning relative to a wound bed of a subject and a subatmospheric pressure mechanism dimensioned to be carried or worn by the subject. The subatmospheric pressure mechanism includes a housing having a control unit adapted to draw a vacuum, a container defining an internal chamber in fluid communication with the vacuum and the wound dressing to receive the wound exudates, a plunger received within the internal chamber and movable during actuation of the control unit and a hydrophobic filter associated with the plunger and permitting escape of gas from the container. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and, together with a general description of the disclosure given above, and the detailed description of the embodiment(s) given below, serve to explain the principles of the disclosure, wherein: 
           [0011]      FIG. 1  is a side view in partial cross-section of the portable wound therapy system of the present disclosure illustrating the wound dressing and the subatmospheric pressure mechanism; 
           [0012]      FIG. 2  is a schematic view illustrating the components of the control unit of the subatmospheric pressure mechanism; 
           [0013]      FIG. 3  is a partial cut-away perspective view of an embodiment of a collection canister according to the present disclosure; 
           [0014]      FIG. 4  is a cross-sectional side view of an embodiment of an expandable collection bag according to the present disclosure; 
           [0015]      FIG. 5  is a perspective side view of another embodiment of an expandable collection bag according to the present disclosure; 
           [0016]      FIG. 6  is a perspective side view of yet another embodiment of an expandable collection bag according to the present disclosure; 
           [0017]      FIG. 7  is a perspective side view of still another embodiment of an expandable collection bag according to the present disclosure; 
           [0018]      FIG. 8  is an interior perspective view of another embodiment of a collection canister according to the present disclosure; 
           [0019]      FIG. 9  is an interior perspective view of yet another embodiment of a collection canister according to the present disclosure; 
           [0020]      FIG. 10A  is a cross-sectional side view of still another embodiment of a collection device according to the present disclosure; and 
           [0021]      FIG. 10B  is a side view of an intake mechanism of the collection device of  FIG. 10A . 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    The wound therapy system of the present disclosure promotes healing of a wound via the use of a wound dressing and a portable subatmospheric pressure mechanism. Generally, the portable subatmospheric pressure mechanism applies subatmospheric pressure to the wound to effectively remove wound fluids or exudates captured by the composite wound dressing, and to increase blood flow to the wound bed and enhance cellular stimulation of epithelial and subcutaneous tissue. The wound therapy system is entirely portable, i.e., it may be worn or carried by the subject such that the subject may be completely ambulatory during the therapy period. The wound therapy system including the subatmospheric pressure mechanism and components thereof may be entirely disposable after a predetermined period of use or may be individually disposable whereby some of the components are reused for a subsequent therapy application. 
         [0023]    The wound therapy system of the present disclosure promotes healing of a wound in conjunction with subatmospheric negative pressure therapy. The system may incorporate a variety of wound dressings, subatmospheric pressure sources and pumps, and collection canisters. The attached figures illustrate exemplary embodiments of the present disclosure and are referenced to describe the embodiments depicted therein. Hereinafter, the disclosure will be described by explaining the figures wherein like reference numerals represent like parts throughout the several views. 
         [0024]    Referring initially to  FIG. 1 , wound therapy system  100  according to the present disclosure is illustrated. Wound therapy system  100  includes composite wound dressing  102  and subatmospheric pressure mechanism  104  in fluid communication with the wound dressing  102  through conduit, identified schematically as reference numeral  106 . 
         [0025]    Wound dressing  102  may includes several components, namely, wound contact layer or member  108 , a wound packing member or filler  110  supported by the contact member  108  and outer layer or cover member  112 . Wound contact member  108  is adapted to substantially conform to the topography of a wound bed “W”. Wound contact member  108  is substantially porous or perforated to permit exudates to pass from the wound bed “W” through the wound contact member  108 . The passage of wound exudates through the wound contact member  108  may be unidirectional such that wound exudates do not flow back to the wound bed “W”. Unidirectional flow may be encouraged by directional apertures formed in contact member  108  or a lamination of materials having absorption properties differing from those of contact member  108 . A non-adherent material may be selected such that contact member  108  does not tend to cling to wound bed “W” or surrounding material when it is removed. One exemplary material that may be used as a contact member  108  is sold under the trademark XEROFLOW® by Tyco Healthcare Group LP (d/b/a Covidien). 
         [0026]    Wound packing member  110  of wound dressing  102  is intended to absorb and transfer wound fluid and exudates. Wound packing member  110  is conformable to assume the shape of any wound bed “W”. Wound packing member  110  may be treated with agents such as polyhexamethylene biguanide (PHMB) to decrease the incidence of infection, or other medicants to promote healing of the wound. A suitable wound packing material  110  is the antimicrobial dressing sold under the trademark KERLEX® AMD by Tyco Healthcare Group LP (d/b/a Covidien). 
         [0027]    Outer member or wound covering  112  encompasses the perimeter of the wound dressing  102  to surround wound bed “W” and to provide a liquid-tight seal around the perimeter “P” of the wound bed “W”. For instance, the sealing mechanism may be any biocompatible adhesive bonded to the perimeter of wound covering  112 . Thus, wound covering  112  may act as both a microbial barrier and a fluid barrier to prevent contaminants from entering wound bed “W” and for maintaining the integrity thereof 
         [0028]    Wound covering  112  is typically a flexible material, e.g., resilient or elastomeric, that seals the top of wound dressing  102  to prevent passage of liquids or contamination to and from the wound dressing  102 . Wound covering  112  may be formed from a moisture vapor permeable membrane to promote the exchange of oxygen moisture between the wound bed “W” and the atmosphere. A membrane that provides a sufficient moisture vapor transmission rate is a transparent membrane sold under the trade name POLYSKIN® II by Tyco Healthcare Group LP (d/b/a Covidien). A transparent membrane permits an assessment of wound conditions to be made without requiring removal of the wound covering  112 . Alternatively, wound covering  112  may comprise an impermeable membrane or a substantially rigid membrane. 
         [0029]    Wound covering  112  may include a port or connector  107  in fluid communication with the interior of wound dressing  102  to facilitate connection of wound dressing  102  to conduit or tubing  106 . Conduit  106  defines a fluid flow path leading through wound therapy system  100 . Connector  107  may be configured as a rigid or flexible, low-profile component, and may be adapted to receive conduit  106  in a releasable and fluid tight manner. A hollow interior of connector  107  provides fluid communication between conduit  106  and the interior of wound dressing  102 . Connector  107  may have a valve  109  built therein, e.g., a one-way valve to permit exudates to flow in one direction only, i.e., away from wound dressing  102  toward subatmospheric pressure mechanism  104 . Connector  107  may be provided as a pre-affixed component of wound dressing  102 , as a component of conduit  106 , or entirely separate and connected thereto by conventional means. Alternatively, connector  107  may be eliminated if other provisions are made for providing fluid communication between wound dressing  102  and conduit  106 . 
         [0030]    Conduit  106  extends from subatmospheric pressure mechanism  104  to provide fluid communication between the interior of the wound dressing  102  and vacuum source  118 . Any suitable conduit may be used including those fabricated from flexible elastomeric or polymeric materials. Conduit  106  may connect to vacuum source  118  or other system components by conventional air tight means such as friction fit, bayonet coupling, or barbed connectors. The conduit connections may be made permanent, or alternatively a quick-disconnect or other releasable means may be used to provide some adjustment flexibility to the apparatus. 
         [0031]    Referring now to the schematic diagram of  FIG. 2 , in conjunction with  FIG. 1 , control unit  116  of subatmospheric pressure mechanism  104  will be discussed. Control unit  116  includes vacuum source or pump  118  disposed within housing  117 , actuator or motor  120  disposed within housing  117  for activating the vacuum source  118  and power source  122  mounted relative to housing  117 . Vacuum source or pump  118  generates or otherwise provides negative pressure to wound therapy system  100 . Vacuum source or pump  118  may be a pump of the diaphragmatic, peristaltic or bellows type or the like, in which the moving part(s) draw exudates out of the wound bed “W” into the wound dressing  102  by creating areas or zones of decreased pressure e.g., vacuum zones with the wound dressing  100 . This area of decreased pressure preferably communicates with the wound bed “W” to facilitate removal of the fluids therefrom and into the absorbent or non-absorbent packing member  110 . One suitable peristaltic pump is the Kangaroo Enteral Pump manufactured by Tyco Healthcare Group LP (d/b/a Covidien). 
         [0032]    Vacuum source or pump  118  may be a miniature pump or micropump that is biocompatible and adapted to maintain or draw adequate and therapeutic vacuum levels. The vacuum level of subatmospheric pressure achieved may be in the range of about 20 mmHg to about 500 mgHg. In some embodiments, about 75 mmHg and about 125 mmHg is desired or between about 35 mmHg and 75 mmHg may be desired. Vacuum source or pump  118  is actuated by actuator  120  which may be any means known by those skilled in the art, including, for example, AC motors, DC motors, voice coil actuators, solenoids, etc. Actuator  120  may be incorporated within pump  118 . 
         [0033]    On an exhaust side of vacuum source  118  fluid conduit  106  connects vacuum source  118  to collection canister  132 . Conduit  106  may comprise the same material or construction along the entire length of the tubing or may assume an alternate form between vacuum source  118  and canister  132  than between wound dressing  102  and vacuum source  118 . In the alternative, it may be separate tubing. 
         [0034]    Power source  122  may be disposed within housing  117  or separately mountable to the housing  117 . A suitable power source  122  includes alkaline batteries, wet cell batteries, dry cell batteries, nickel cadmium batteries, solar generated means, lithium batteries, NiMH batteries (nickel metal hydride) each of which may be of the disposable or rechargeable variety. 
         [0035]    Referring again to  FIG. 1 , subatmospheric pressure mechanism  104  includes collection canister  132  which collects the exudates removed from the wound bed “W” during therapy through conduit, or tubing,  106 . Collection canister  132  is releasably connected to housing  117  of control unit  116 . Collection canister  132  may comprise any container suitable for containing wound fluids and is substantially rigid defining an internal chamber  133  in fluid communication with tubing  106 . Collection canister  132  may contain an absorbent material to consolidate or contain the wound drainage or debris. In embodiments, at least a portion of collection canister  132  may be transparent to assist in evaluating the color, quality, or quantity of wound exudates. A transparent canister may thus assist in determining the remaining capacity of canister  132  or when the canister  132  should be replaced. In the alternative, collection canister  132  may be relatively flexible. 
         [0036]    Turning now to  FIG. 3 , an embodiment of a collection canister according to the present disclosure is shown generally as collection canister  232 . Collection canister  232  includes a substantially rigid housing  204  defining a chamber  204   a  for receiving a collection bag  202 . A cover  206  is configured to engage container  204  to for a sealed chamber  204   a.  Alternatively, cover  206  may be integrally formed with housing  117 . Cover  206  defines an inlet port  206   a  and an outlet port  206   b.  Inlet port  206   a  is in fluid communication with wound dressing  102  and is configured to receive fluid “F” or exudates therefrom. A check valve  212  may be integrally formed with cover  206 . Outlet port  206   b  is operably connected to vacuum source or pump  118 . Outlet port  206  includes an extension  207 . Extension  207  extends within chamber  204   a  of container  204 . Extension  207  includes a channel  207   a  or other suitable configuration to ensure suction continues to be provided to chamber  204   a  as collection bag  202  expands to fill chamber  204   a.    
         [0037]    Collection bag  202  includes an expandable cavity  202   a  configured for receiving fluid “F”. Collection bag  202  is constructed with a hydrophobic membrane or other suitable material capable of permitting gases to escape cavity  202   a.  Alternatively, collection bag  202  may have a hydrophobic vent (not shown). Collection bag  202  is maintained in fluid communication with inlet port  206   a.  It is envisioned that collection bag  202  may be integrally formed with cover  206 . 
         [0038]    In operation, suction from pump  118  is provided to chamber  204   a  of container  204  through outlet port  206   b.  As a vacuum builds within chamber  204   a  suction is provided to wound dressing  102  to draw fluid “F” from wound “W”. As fluid “F” flows from wound “W” through inlet port  206   a  into cavity  202   a  of collection bag  202 , any residual air or other gases in the system pass through collection bag  202 . Cavity  202   a  expands to accommodate fluid “F” as the flow into collection bag  202  continues. Check valve  212  prevents fluid “F” from flowing from cavity  202   a  back towards wound dressing  102 . Alternatively, check valve  212  may be formed on a distal end  106   b  of conduit  106 . Collection bag  202  continues to expand as fluid “F” is drawn from wound “W”. Channel  207   a  formed in extension  207  of outlet port  206   b  is configured to permit the continued flow of suction into chamber  204   a,  thereby allowing collection bag  202  to expand to fill chamber  204   a.  Once collection bag  202  and/or chamber  204   a  is filled, cover  206  may be removed and collection bag  202  may be emptied and/or replaced. 
         [0039]    With reference now to  FIG. 4 , an alternate embodiment of a collection bag for use in collection canister  232  is shown as collection bag  202 ′. Collection bag  202 ′ defines an expandable cavity  202   a ′ for receiving fluids. A sealing band  204 ′ maintains collection bag  202 ′ in a sealed relationship with patient tube with inlet port  206   a  of cover  206 . A check valve  212 ′ is positioned on a distal end  106   b  of a conduit  106  to prevent back flow of fluid from collection bag  202 ′ into conduit  106 . 
         [0040]    Collection bag  202 ′ includes a bulb-shaped container constructed of rubber, polymer or other expandable material. As noted above, collection bag  202 ′ defines an expandable cavity  202   a ′. Collection bag  202 ′ further includes a hydrophobic plug  203 ′ for releasing gas from within cavity  202   a ′. As fluid “F” flows from conduit  106  through check valve  212 ′ and into cavity  202   a ′ of collection bag  202 ′, collection bag  202 ′ expands to accommodate the additional fluid. Any gas trapped within cavity  202   a ′ may be vented through hydrophobic plug  203 ′. Collection bag  202 ′ may be removed from conduit  106  and discarded as necessary. It is envisioned that collection bag  202 ′ may be reused. Collection bag  202 ′ may optionally include a tie, draw string or other suitable closure device for sealing cavity  202   a′.    
         [0041]    Turning to  FIG. 5 , an alternate embodiment of a collection bag of the present disclosure is shown generally as collection bag  302 . Collection bag  302  includes a pleated container constructed of a hydrophobic material, e.g. TYVEK. This construction permits any air or other gases trapped with the collection system to pass through collection bag  302  while collecting fluid “F” ( FIG. 3 ) therein. Collection bag  302  defines an expandable cavity  302   a  for receiving fluids. In one embodiment, collection bag  302  is preferably configured to expand to fill chamber  204   a  of collection canister  232 . Collection bag  302  may further include a window  303  for viewing the contents of cavity  302   a.  As fluid enters cavity  302   a  of collection bag  302 , pleats  301  formed in collection bag  302  expand to increase the capacity of cavity  302   a  and accommodate the additional fluid. 
         [0042]    With reference now to  FIG. 6 , another embodiment of a collection bag of the present disclosure is shown as collection bag  402 . Collection bag  402  is constructed of hydrophobic material and includes accordion-like folds  401 . Folds  401  are configured to expand as collection bag  402  fills with fluid “F” ( FIG. 3 ). 
         [0043]    Turning now to  FIG. 7 , yet another embodiment of a collection bag is shown generally as collection bag  502 . Collection bag  502  is constructed from hydrophobic material that is rolled. Collection bag  502  may include a window (not shown) for viewing the contents therein. 
         [0044]    Turning now to  FIG. 8 , another embodiment of the present disclosure is shown generally as collection device  600 . Collection device  600  includes a container  604  defining a first chamber  606  in fluid communication with a second chamber  608  separated by a divider  607 . Container  604  further includes an inlet port  604   a  in fluid communication with first chamber  606  and one or more outlet ports  604   b  in fluid communication with the second chamber  608 . Inlet port  604   a  is operably connected to conduit  106 ′. Conduit  106 ′ may include a check valve (not shown). Outlet ports  604   b  are operably connected to a source of suction not shown. 
         [0045]    A plunger  610  is retained within second chamber  608  of container  604 . Plunger  610  is a substantially planar member including a hydrophobic membrane  612  and a seal  214   a  extending about a perimeter  214  of plunger  610 . Plunger  610  is configured to be advanced in the direction of arrow A as suction is applied to outlet ports  604   b  and air is removed from within second chamber  608 . Alternatively, it is envisioned that plunger  610  may be attached to an advancement mechanism, including hydraulic, pneumatic and motorized cylinder, for advancing plunger  610 . Movement of plunger  610  towards outlets  604   b  (direction of arrow “A”) creates a vacuum in first chamber  606 . The vacuum created in first chamber  606  provides suction to conduit  106 ′. As plunger  610  is drawn towards outlets  604   b  fluid “F” fills first and second chamber  606 ,  608 . Residual air trapped within container  604  and/or conduit  106 ′ is exhausted though hydrophobic membrane  612 . Once first and second chambers  606 ,  608  are filled, conduit  106 ′ is disconnected from container  604 . Collection device  600  may include a valve or other mechanism (not shown) for draining container  604 . Alternatively, collection device  600  may be discarded. 
         [0046]    Turning now to  FIG. 9 , another embodiment of the present disclosure is shown generally as collection device  700 . Collection device  700  is substantially similar to collection device  600  and includes a container  704  having a first chamber  706  in fluid communication with a second chamber  708 . First and second chambers  706 ,  708  are separated by a divider. An inlet port  704   a  fluidly communicates conduit  106 ′ with first chamber  706 . An outlet port  704   b  fluidly communicates second chamber  708  with a vacuum source (not shown). A plunger  710  is received within first chamber  706 . Plunger  710  includes a hydrophobic membrane  212 . Plunger  710  is configured to create a vacuum in first chamber  706  as plunger  710  is advanced in the direction of arrow “B”. The vacuum in first chamber  706  causes fluid “F” to be drawn through conduit  106 ′. Once first chamber  706  is filled, conduit  106 ′ is disconnected from container  704 . Collection device  700  may include a valve or other mechanism (not shown) for draining container  704 . Alternatively, collection device  700  may be discarded. 
         [0047]    With reference now to  FIGS. 10A and 10B , an alternate embodiment of the present disclosure is shown generally as collection canister  800 . Collection device  800  includes a container  804  having a cover  806  and defining a substantially sealed chamber container  804   a.  An inlet port (not shown) may be formed in container  804  and/or cover  806 . Cover  806  further includes an outlet port  806   b  configured for operable connection with a vacuum source. Cover  806  further includes a flange  807  extending inwardly from outlet port  806   b.  An intake mechanism  810  extends from flange  807  and is in fluid communication with outlet port  806   b.    
         [0048]    Intake mechanism  810  includes a bellows  812  and a float  814 . Bellows  812  may be constructed of silicone or other suitable flexible material. Bellows  812  defines a passageway  812  therethrough in fluid communication with outlet port  806   b.  Bellows  812  includes openings  813  for receiving air from with chamber  804   a.  Float  814  may include an air bag, open cell material or other suitable material with a low mass. Float  814  may be affixed to an end of bellows  812 . Alternatively, float  814  may be over-molded to bellows  812 . Float  814  is configured to maintain at least one of openings  813  formed in bellows  812  above the level of fluid “F” as chamber  804   a  fills with fluid “F”. Bellows  812  and float  814  are configured such that as container  804  is transported, i.e. tilted or inverted, collection device  800  continues to collect fluid “F”. 
         [0049]    Although the illustrative embodiments of the present disclosure have been described herein with reference to the accompanying drawings, it is to be understood that the disclosure is not limited to those precise embodiments, and that various other changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the disclosure.