PATENT ABSTRACT
A portable system for subatmospheric pressure therapy in connection with healing a surgical wound is provided. The system includes a wound dressing dimensioned for positioning relative to a wound bed of a subject, and a collection canister in fluid communication with the wound dressing. The canister includes a base defining a fluid receiving cavity and having a fluid inlet port and a vacuum port. The fluid inlet port is configured for fluid communication with a wound dressing, The system further includes a cover selectively engageable to the base, e.g., in a snap-fit manner. The cover is configured to receive a control unit and has a vent assembly for exhausting the control unit. A seal member is interposed relative to the base and the cover to establish and maintain a substantial sealed relationship between the two components when assembled.

PATENT DESCRIPTION
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 13/186,599, filed Jul. 20, 2011, which is a continuation of U.S. patent application Ser. No. 12/175,038, filed on Jul. 17, 2008, and issued as U.S. Pat. No. 8,007,481 on Aug. 30, 2011. The disclosures of these prior applications are hereby incorporated herein by reference in their entirety. 
     
    
     BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present disclosure relates to treating an open wound, and, more specifically, relates to a wound therapy system including an improved subatmospheric pressure mechanism. 
         [0004]    2. Description of the Related Art 
         [0005]    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. 
         [0006]    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. 
         [0007]    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 wound area through the fluid conduit to stimulate healing of the wound. Exudates drawn from the wound area may be deposited in a collection canister or container. 
         [0008]    Subatmospheric pressure mechanisms used in wound therapy systems may include a cavity or chamber for receiving the removed exudates, a vacuum source, and a power source. The pressure mechanisms are configured to provide the suction that draws exudates from the wound. Unfortunately, conventional subatmospheric pressure mechanisms have a tendency to develop leaks. Leaks may reduce the efficiency of the system and/or create odor and wetness issues. 
       SUMMARY 
       [0009]    Accordingly, the present disclosure relates to an improved subatmospheric pressure mechanism. A portable system for subatmospheric pressure therapy in connection with healing a surgical wound is provided. The system includes a wound dressing dimensioned for positioning relative to a wound bed of a subject, and a collection canister in fluid communication with the wound dressing. The canister may include a base defining a fluid receiving cavity and having a fluid inlet port and a vacuum port. The fluid inlet port is configured for fluid communication with a wound dressing. A cover is selectively engageable to the base, e.g., in a snap-fit manner. The cover accommodates a control unit and a vent assembly for exhausting the control unit. A seal member is interposed relative to the base and the cover and is adapted to establish and maintain a sealed relationship between these components. At least one of the fluid inlet port and the vacuum port may be configured to receive a cap. 
         [0010]    The control unit of the system may include a vacuum source and/or a power source. The vacuum port may also include a hydrophobic membrane. The vent assembly may be recessed relative to the base or cover. The system may further include a divider having a plurality of longitudinal grooves formed on an underside thereof. The divider may further include a channel fluidly communicating the plurality of longitudinal grooves with at least one of the fluid inlet port and the vacuum port. The control unit may be directly connected to the vent assembly. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    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: 
           [0012]      FIG. 1  is a view of a wound therapy system in accordance with the principles of the present disclosure; 
           [0013]      FIG. 2  is a side cross-sectional view of the subatmospheric pressure mechanism of the wound therapy system of  FIG. 1 ; 
           [0014]      FIG. 3  is a side cross-sectional side view of the subatmospheric pressure mechanism of  FIG. 2 , illustrating the housing cover separated from the housing base; 
           [0015]      FIG. 4A  is an enlarged side cross-sectional view of the vent assembly of the subatmospheric pressure mechanism of  FIGS. 2 and 3 ; 
           [0016]      FIG. 4B  is an enlarged plan view of the vent assembly of  FIG. 4A ; 
           [0017]      FIG. 5A  is an enlarged side cross-sectional view of an alternate embodiment of the vent assembly of the subatmospheric pressure mechanism of  FIGS. 2 and 3 ; 
           [0018]      FIG. 5B  is an enlarged front view of the vent assembly of  FIG. 5A ; 
           [0019]      FIG. 6  is a perspective view of another subatmospheric pressure mechanism of the present disclosure; 
           [0020]      FIG. 7  is a perspective view of another embodiment of the subatmospheric pressure mechanism; 
           [0021]      FIG. 8  is a plan view of the divider of the subatmospheric pressure mechanism of  FIG. 7 ; 
           [0022]      FIG. 9  is cross-sectional end view of the divider of  FIG. 8  taken along line  9 - 9 ; and; 
           [0023]      FIG. 10  is a cross-sectional view of the divider of  FIG. 8  taken along line  10 - 10 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0024]    The following figures illustrate 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. 
         [0025]    Referring initially to  FIG. 1 , a wound therapy system of the present disclosure is shown generally as wound therapy system  100 . Wound therapy system  100  includes composite wound dressing  102  and subatmospheric pressure mechanism  104  in fluid communication with the wound dressing  102  through a conduit, identified schematically as reference character “c”. For a more detailed description of wound dressing  102 , including the composition and operation thereof, please refer to commonly owned U.S. patent application Ser. No. 12/047910, filed Mar. 13, 2008, the contents of which are incorporated herein by reference in their entirety. 
         [0026]    With reference now to  FIGS. 2-3 , subatmospheric pressure mechanism  104  will be described in detail. Subatmospheric pressure mechanism  104  may be a portable canister adapted to be worn or carried by the subject via a strap, belt, or the like. In the alternative, pressure mechanism  104  may be a component of a non-ambulatory system. Subatmospheric pressure mechanism  104  includes housing base  110  and housing cover  120  selectively attachable to housing base  110 . Housing base  110  and/or housing cover  120  may be fabricated from substantially rigid material, or in the alternative, include a relatively flexible material. Housing base  110  defines a first cavity  111  for receiving fluid, e.g. exudates “E” from wound dressing  102  ( FIG. 1 ). Housing cover  120  defines a second cavity  121  to accommodate, e.g., a control unit for controlling operation of system  100 . The control unit may consist of vacuum source  5   150 , power source  160 , and logic software and/or processing means for controlling operation of vacuum source  150  based on various parameters and/or in connection with a treatment regimen. 
         [0027]    Housing base  110  and housing cover  120  may be adapted for releasable coupling. In one embodiment. housing base  110  includes flange  112  and notch or recess  114 . Flange  112  is configured to engage lip  122  formed in housing cover  120 . Notch  114  is configured to selectively receive a tab  126  of an extension  124  of housing cover  120 . Housing base  110  further includes a fluid inlet  116  and a suction port  118 . Fluid inlet  116  is configured to operably engage conduit “c” and may include a luer lock  112   a.  Inlet  116  is preferably configured to receive cap  116   a  for preventing leakage of exudates “E” and odor from first cavity  111  when housing cover  120  is separated from housing base  110 . Suction port  118  is configured to operably engage vacuum source  150 . Suction port  118  may include a hydrophobic membrane or filter  115  for preventing exudates “E” from being aspirated into vacuum source  150 . Suction port  118  may also be configured to receive cap  118   a  to prevent fluid leakage during disposal of housing base  110 . 
         [0028]    With reference still to  FIGS. 2 and 3 , housing cover  120  is configured for releasable engagement with housing base  110  and includes second cavity  121  for receiving vacuum source  150  and power source  160 . Vacuum source  150  and/or power source  160  may be maintained with housing cover  120  with rubber mounts (not shown) for reducing vibration within housing cover  120 . Housing cover  120  may be constructed of and/or include STYROFOAM® or other sound dampening material. Housing cover  120  may include an overlay, having lights and/or buttons (not shown) for monitoring and controlling the operation of subatmospheric pressure mechanism  104 . Housing cover  120  includes lip  122  configured to engage flange  112  of housing base  110 . An extension  124  extends from housing cover  120  opposite lip  122  and is configured for operable engagement by a user. Extension  124  includes tab  126  configured to engage notch  114  formed in housing base  110 . Extension  124  is configured to flex such that tab  126  may be selectively received within notch  114 , thereby, releasably securing housing cover  120  to housing base  110 . This snap-fit configuration may produce an audible sound when tab  126  is received within notch  114 , thereby, notifying the user that housing cover  120  and housing base  110  are securely joined together. 
         [0029]    Seal member  128  extends about housing cover  120  to form a seal between housing cover  120  and housing base  110  when housing cover  120  is selectively secured to housing base  110 . Seal member  128  may be secured to housing cover  120  in any manner, including mechanical fastening, welding, and adhesive. Alternatively, seal member  128  may extend about housing base  110  to form a seal between housing base  110  and housing cover  120 . In an alternative embodiment, seal member  128  may include two or more seal elements (not shown). Seal member  128  establishes and maintains a sealed relationship between cover  120  and housing base  110  when the components are assembled thereby preserving the integrity of the second cavity  121  within cover  120 . 
         [0030]    Housing cover  120  further includes vent assembly  130  configured to vent exhaust air from vacuum source  150  through exhaust port  130   a.  Turning initially to  FIGS. 4A and 4B , vent assembly  130  extends from housing cover  120  and is directly connected to vacuum source  150  ( FIG. 1 ) via tube  131 . Vent assembly  130  includes filter  132  extending across exhaust port  130   a  and split ring  136  for retaining filter  132  over exhaust port  130   a . Vent assembly  130  includes groove  134  formed about exhaust port  130   a  adapted to receive split ring  136 . Filter  132  is sized and dimension such that an outer portion of filter  132  folds into groove  134  and is retained therein by split ring  136 . Filter  132  may be hydrophobic in nature and/or may include charcoal or other odor absorbing material, and may prevent the passage of bacteria. Split ring  136  may be formed of plastic, metal or other suitable material. Split ring  136  may include openings  136   a  configured to receive a tool for removing split ring  136  from within groove  134 . In this manner, filter  132  may be changed as necessary. 
         [0031]    Turning now to  FIGS. 5A and 58 , in an alternative embodiment, vent assembly  130 ′ may be recessed in housing cover  120 . Additionally, vent assembly  130 ′ may vent exhaust air from within second cavity  121  rather than directly from vacuum source  150  via tube  131 . In this manner, heat may be dissipated from within second cavity  121  in addition to the venting of exhaust from vacuum source  150 . This configuration also provides a positive pressure on filter  132 . Filter  132  is again retained within a groove  134 ′ formed in housing  120  by split ring  136 . 
         [0032]    In operation, subatmospheric pressure mechanism  104  is adapted to draw exudates from wound dressing  102  via conduit “c”. Initially, housing cover  120  is selectively secured to housing base  110 . To secure housing cover  120  to housing base  110 , lip  122  of housing cover  120  is first received within flange  112  of housing base  110 . Housing cover  120  is then pivoted about flange  112  such that extension  124  received over housing base  110 . Housing cover  120  is pivoted until tab  126  of extension  124  is received within notch  114 . Subatmospheric pressure mechanism  104  may be configured such that receipt of tab  126  within notch  114  causes an audible sound, thereby confirming to a user that housing cover  120  has been securely received on housing base  110 . Once subatmospheric pressure mechanism  104  is assembled, conduit “c” may be fluidly coupled to fluid inlet  116  and the control unit (not shown) may be activated. Activation of vacuum source  150  creates suction within first cavity  111  that draws exudates from wound dressing  102  through conduit “c”. Exudates “E” collect in first cavity  111  of housing base  110 . Exhaust from vacuum source  150  is vented either directly or indirectly through vent assembly  130 ,  130 ′, respectively. Heat may also be dissipated through vent assembly  130 ′. 
         [0033]    Upon filling of first cavity  111 , completion of treatment or other any other reason, subatmospheric pressure mechanism  104  may be deactivated and exudates “E” may be properly disposed. To disengage housing cover  120  from housing base  110 , extension  124  of housing cover  120  is flexed away from housing base  110 . In this manner, tab  126  on extension  124  is withdrawn from engagement with notch  114  formed in housing base  120 . Housing cover  120  may be pivoted away from housing base  110  until lip  122  of housing cover  120  disengages flange  112  of housing base  110 . Once housing cover  120  is separated from housing base  110 , exudates “E” may be disposed. Exudates “E” may be emptied from first cavity  111 , or alternatively, housing base  110  may be disposed of in its entirety. In the event housing base  110  is disposed, caps  116   a,    118   a  may be placed in fluid inlet  116  and suction port  118 , respectively, such that housing base  110  may be transported without worry of fluid leakage or odor escaping from within cavity  111 . 
         [0034]    With reference now to  FIG. 6 , a housing base of alternate embodiment of a subatmospheric pressure mechanism is shown as housing base  10 . Housing base  10  includes divider  12  for separating housing base  10  into a fluid receiving portion  10   a  and an operational portion  10   b  configured for receiving a control unit, including a vacuum source and power source (not shown). Divider  12  includes a fluid inlet port  13   a  and a vacuum port  13   b.  Divider  12  further includes a gasket  14  extending about an outer periphery of divider  12 . Gasket  14  is configured to engage vacuum source ( FIG. 2 ) in a sealed manner, thereby enabling a vacuum to be created within fluid receiving portion  10   a  to draw fluid from wound dressing  102  ( FIG. 1 ). 
         [0035]    Turning now to  FIG. 7 , a housing base of an alternative embodiment of the subatmospheric pressure mechanism of the present disclosure is shown generally as housing base  210 . Subatmospheric pressure mechanism  210  includes a divider  212  including a fluid inlet port  213   a  and vacuum port  213   b.  Divider  212  further includes a gasket  214  extending about fluid inlet port  213   a  and vacuum port  213   b  for engaging a vacuum source ( FIG. 2 ) in a sealed manner. By localizing gasket  214  around fluid inlet port  213   a  and vacuum port  213   b  the likelihood of scaling issues, such as air and fluid leaks, is reduced. Gasket  214  may be formed of gel or other suitable sealing material. One preferred gel material is a silica gel. 
         [0036]    With reference now to  FIGS. 8-10 , underside  212   a  of divider  212  is configured to assist in fluid collection. Divider  212  includes a plurality of longitudinal grooves  214  extending the length thereof. Channel  216  extends the width of divider  212  in alignment with fluid inlet port  213   a  and vacuum port  213   b.  Channel  216  fluidly communicates each of the plurality of longitudinal grooves  214  with fluid inlet port  213   a  and vacuum port  213   b . Divider  212  may be integrally formed with housing base  210 , or as shown configured to be received within housing base  210 . In this manner, divider  212  is sealed within housing base  210  using a hydrophobic adhesive or other suitable bonding material (not shown). Divider  212  may further include a hydrophobic membrane  218  at least partially covering longitudinal grooves and vacuum port  213   b.  Hydrophobic membrane  216  provides a fluid barrier between the fluid collection chamber and the control mechanism. Longitudinal grooves  214  provide increased surface area for air flow through hydrophobic membrane  218 . This may assist vacuum flow, e.g., in the event that a portion of the surface area becomes clogged and/or covered with exudate “E” or other fluid. 
         [0037]    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.