Patent Publication Number: US-2009240218-A1

Title: Wound Therapy System

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to, and the benefit of, U.S. Provisional Patent Application No. 61/038,301, filed Mar. 20, 2008, U.S. Provisional Patent Application No. 61/052,007, filed May 9, 2008, U.S. Provisional Patent Application No. 61/060,869, filed Jun. 12, 2008 and U.S. Provisional Patent Application No. 61/146,051, filed Jan. 21, 2009, the entire contents of each reference being incorporated herein by reference. 
    
    
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to treating an open wound, and, more specifically, relates to a portable wound therapy system. 
     2. Description of Related Art 
     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. 
     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. 
     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. The various components of the wound therapy system may need to be disconnected or be replaced for a variety of reasons, such as component failure or different component life expectancies. It would be advantageous to provide a user friendly mechanism for connecting and disconnecting components of the system. 
     SUMMARY 
     Accordingly, a portable system for subatmospheric pressure therapy is utilized in connection with healing a surgical wound. The system includes a wound dressing dimensioned for positioning relative to a wound bed of a subject and a portable subatmospheric pressure mechanism dimensioned to be carried or worn by the subject. The subatmospheric pressure mechanism includes a housing having a control unit, a collection canister, and means for releasably connecting the housing and the canister. 
     Various embodiments of means for releasably coupling the housing and the canister are disclosed, including latch couplings, bayonet mounts, fastening mechanisms, and magnetic couplings. The connection means may facilitate the connection, disconnection, or maintenance of components of the system including the replacement of the collection canister. The connection means permits the collection canister to be released for emptying or disposal during a course of therapy. In one method of application, the collection canister collects exudates from the wound bed which has been removed under subatmospheric pressure supplied by the control unit. When full, the collection canister is removed and replaced with a new canister which is also connectable through connection means with the housing of the control unit. The control unit may be intended for reuse. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various embodiments of the wound dressing system of the present disclosure are described herein with reference to the drawings wherein: 
         FIG. 1A  is a view of the portable wound therapy system of the present disclosure illustrating the wound dressing in cross-section and the subatmospheric pressure mechanism; 
         FIG. 1B  is a cross-sectional view of a subatmospheric pressure mechanism in accordance with the present disclosure; 
         FIG. 2A  is a perspective view of the subatmospheric pressure mechanism illustrating the control unit housing, collection canister and a latch coupling for releasably connecting the collection canister to the control unit housing; 
         FIG. 2B  is a side plan view of the latch coupling of  FIG. 2A ; 
         FIG. 2C  is a perspective view of another embodiment of a latch coupling mechanism for releasably connecting the control unit housing and the collection canister; 
         FIG. 2D  is a side plan view of the latch coupling mechanism of  FIG. 2C ; 
         FIG. 3A  is a perspective view of another embodiment of a latch coupling mechanism for releasably connecting the control unit housing and the collection canister; 
         FIG. 3B  is a perspective view of another embodiment of a latch coupling mechanism of  FIG. 3A ; 
         FIGS. 4A-4D  are perspective views of other alternative embodiments of a latch coupling mechanism for releasably connecting the control unit housing and the collection canister; 
         FIG. 5  is a perspective view of the collection canister including a second coupling mechanism utilizing a tongue; 
         FIG. 6A  is a cross-sectional view of another embodiment of a latch coupling mechanism for releasably connecting the control unit housing and the collection canister; 
         FIG. 6B  is a cross-sectional view of the latch coupling mechanism of  FIG. 6A  in a disengaged position; 
         FIG. 7A  is a cross-sectional view of another embodiment of a latch coupling mechanism for releasably coupling the control unit housing and the collection canister and depicted in an engaged position; 
         FIG. 7B  is a cross-sectional view of the latch coupling of  FIG. 7A  in a disengaged position; 
         FIG. 8A  is a view of a carrier support apparatus for supporting components of the subatmospheric pressure mechanism; 
         FIG. 8B  is a view of an alternate carrier support apparatus for supporting components of the subatmospheric pressure mechanism of the present disclosure; 
         FIG. 9  is a perspective view illustrating one embodiment of a bayonet mount for releasably mounting the control unit housing and the collection canister of the subatmospheric pressure mechanism; 
         FIGS. 10A-10C  are partial cross-sectional views illustrating a sequence of operation for connecting the collection canister and the control unit housing with the bayonet mount of  FIG. 9 ; 
         FIG. 11  is a perspective view illustrating another embodiment of a bayonet mount for releasably mounting the control unit control unit housing and the collection canister of the subatmospheric pressure mechanism; 
         FIGS. 12A-12C  are partial cross-sectional views illustrating a sequence of operation for connecting the collection canister and the control unit housing with the bayonet mount of  FIG. 11 ; 
         FIGS. 13-15B  are views of different embodiments of the subatmospheric pressure mechanism having strap fasteners; 
         FIGS. 16A-21B  are views of different embodiments of the subatmospheric pressure mechanism having complementary fastening elements on the periphery of the housing and the canister; 
         FIGS. 22A and 22B  are views of an embodiment of the subatmospheric pressure mechanism having spring-loaded button fasteners in an uncoupled and coupled state, respectively; 
         FIGS. 23 and 24  are views of alternate embodiments of a subatmospheric pressure mechanism having a spring-loaded button fastener; 
         FIGS. 25 and 26  are views of different embodiments of the subatmospheric pressure mechanism having a slide fastener; 
         FIGS. 27A-28  are views of alternate embodiments of a subatmospheric pressure mechanism each having a spring-assisted clip fastener; 
         FIGS. 29A and 29B  are view of an embodiment of the subatmospheric pressure mechanism having movable clip fasteners in an uncoupled and coupled state; 
         FIG. 30A  is a cross-sectional view of a magnetic coupling of the control unit and the collection canister of the subatmospheric pressure mechanism; 
         FIG. 30B  is a cross-sectional view of an alternate magnetic coupling arrangement of the control unit and collection canister; 
         FIG. 30C  is a cross-sectional view of another alternate magnetic coupling arrangement of the control unit and collection canister; 
         FIGS. 30D-30F  are top plan views of different magnet configurations within the control unit; and 
         FIG. 31  is a cross-sectional view of a magnetic coupling of the control unit and the collection canister via use of permanent magnets. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     The wound therapy system of the present disclosure promotes healing of a wound via the use of a wound dressing and a subatmospheric pressure mechanism. Generally, the 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 may be 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. 
     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. 
     Referring initially to  FIG. 1A , 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  106 . 
     Wound dressing  102  may include 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. Exemplary materials that may be used as a contact member  108  are sold under the trademarks CURITY® Non-Adherent Dressing or XEROFLO® by Tyco Healthcare Group, LP (d/b/a Covidien) 
     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 KERLIX™ by Tyco Healthcare Group, LP (d/b/a Covidien). 
     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. 
     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. 
     Wound covering  112  may include a port or connector  114  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  114  may be 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  114  provides fluid communication between conduit  106  and the interior of wound dressing  102 . Connector  114  may have a valve built (not shown), 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  114  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  114  may be eliminated if other provisions are made for providing fluid communication between wound dressing  102  and conduit  106 . 
     Conduit  106  extends from subatmospheric pressure mechanism  104  to provide fluid communication between the interior of the wound dressing  102  and subatmospheric pressure mechanism  104 . Any suitable conduit may be used including those fabricated from flexible elastomeric or polymeric materials. Conduit  106  may connect to subatmospheric pressure mechanism  104  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. Fluid conduit  106  may comprise the same material of construction along the entire length of the tubing or may assume an alternate form, e.g., it may include several distinct tubes connected to each other through conventional means. 
     Subatmospheric pressure mechanism  104  will be discussed subatmospheric pressure mechanism  104  includes control unit  116  and collection canister  118 . Control unit  116  has control unit housing  120  which houses the software, logic and components required to operate the subatmospheric pressure mechanism  104 . 
     Referring now to  FIG. 1B , the electronic, electrical and pneumatic components of the subatmospheric pressure mechanism  104  will be discussed. Subatmospheric pressure mechanism  104  may incorporate vacuum source or pump  164 , actuator or motor  166  for activating the vacuum source  164 , and power source  168 . Vacuum source or pump  164  generates or otherwise provides negative pressure to wound therapy system  100 . Vacuum source or pump  164  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  102 . 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 . 
     Vacuum source or pump  164  may be a miniature pump or micropump that may be 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 mmHg. In embodiments, the vacuum level may be about 75 mmHg and about 125 mmHg, or between about 30 mmHg and 80 mmHg. Vacuum source or pump  164  is actuated by actuator  166  which may be any means known by those skilled in the art, including, for example, AC motors, DC motors, voice coil actuators, solenoids, and the like. Actuator  166  may be incorporated within pump  164 . 
     Power source  168  may be disposed within housing  120  or separately mountable to housing  120 . A suitable power source  168  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. 
     Housing  120  may further include vent portal  170  configured to vent exhaust air from vacuum source or pump  164  through exhaust port  172 . Vent portal  170  extends from housing  120  and may be directly connected to vacuum source  164 . It is also envisioned that vent portal  170  may exhaust air from within housing  120  rather than directly from vacuum source  164 . Exhaust port  172  may include filter  174  extending across the exhaust port  172 . Filter  174  may be a bacterial filter to prevent emission of bacteria from housing  120 . A PCB may be provided along with a pressure transducer to control output of the pump in response to pressure measurements calculated in the collection canister. 
     Collection canister  118  collects exudates “e” removed from the wound bed “w” during therapy through conduit or tubing  106 . A fluid inlet  178  and suction port  180  may be maintained between the housing  120  and the canister  118 . Fluid inlet  178  is configured to operably engage conduit  106 . Fluid inlet  178  may be connectable with conduit  106  by conventional air and fluid tight means, such as those described above. In embodiments, fluid inlet  178  may contain a luer lock or other connector within the purview of those skilled in the art to secure the end of conduit  106  with the fluid inlet  178 . It is envisioned that fluid inlet  178  is configured to receive a cap in order to prevent leakage of exudates and odor from internal chamber  176  of collection canister  118  when housing  120  is separated from the canister  118 . 
     Suction port  180  is in fluid communication with vacuum source or pump  164 . A filter  182 , such as a hydrophobic membrane or baffling to prevent exudates from being aspirated into pump  164  may be disposed adjacent or within suction port  180 . Filter  182  may also include charcoal or other odor absorbing materials and may prevent the passage of bacteria. Pump  164  creates a vacuum within internal chamber  176  of collection canister  118  by drawing air through suction port  180 . 
     Collection canister  118  collects the exudates removed from the wound bed “w” during therapy through conduit, or tubing,  106 . Collection canister  118  is releasably connected to housing  120  of control unit  116 . Collection canister  118  may include any container suitable for containing wound fluids. Collection canister  118  may be substantially rigid in order to maintain the integrity and shape of the canister as a stand alone component. In the alternative, collection canister  118  may be relatively flexible and/or partly expandable to accommodate the wound exudates. Collection canister  118  may contain an absorbent material to consolidate or contain the wound drainage or debris. In other embodiments, at least a portion of collection canister  118  may be transparent to assist in evaluating the color, quality, or quantity of wound exudates. This transparency may assist in determining the remaining capacity of the canister or when the canister should be replaced. 
     Referring now to  FIG. 2A , subatmospheric pressure mechanism  104  includes a latch coupling mechanism  122  adapted for selectable releasable coupling of control unit housing  120  and collection canister  118 . Latch coupling mechanism  122  may facilitate the connection, disconnection, or maintenance of components of system  100 , including the replacement of collection canister  118 . Latch coupling mechanism  122  includes first and second coupling segments  124 ,  126  associated with control unit housing  120  and collection canister  118 , respectively. First coupling segment  124  may be a latch having locking surface  128 . Locking surface  128  may be a curved or angular portion adapted for releasable engagement with second coupling segment. Second coupling segment  126  includes a notch or locking slot  130  for receiving latch. In the alternative, first coupling segment  124  of control unit housing  120  may be in the form of a locking slot while second coupling segment  126  of collection canister  118  may be a latch. 
     Latch coupling mechanism  122  is placed in the engaged position through insertion of first coupling segment or latch  124  within locking slot  130  whereby locking surface  128  engages portions of collection canister  118  defining the locking slot  130  in secured relation therewith. Latch coupling mechanism  122  is released by depressing latch  124  inwardly in the direction of directional arrow “k” of  FIG. 2B  toward collection canister  118  such that locking surface  128  is released from within locking slot  130 . Latch  124  has sufficient flexibility to pivot out of engagement with collection canister  118  during movement to the release position. In one embodiment, latch  124  is monolithically formed with control unit housing  120 . Once release is achieved, housing  120  may be lifted from collection canister  118 . 
       FIGS. 2C and 2D  illustrate another embodiment of the latch coupling mechanism. Latch coupling mechanism  200  incorporates elongated latch  202  defining a general “z-shape,” and having locking surface  204  positioned substantially at the center of the latch  202 . This arrangement of latch  202  provides a manually engaging segment  206  depending from locking surface  204 , which is relatively elongated and displaced from the wall of collection canister  118 . The displaced orientation, in conjunction with the elongated characteristic, may provide mechanical advantages and enhance relative ease of manipulation and/or control of the latch  202  for the clinician. Latch  202  cooperates with locking slot  130  to releasably couple collection canister and control unit housing  120  in a manner similar to the embodiment of  FIGS. 2A-2B . 
       FIG. 3A  illustrates an alternate embodiment of the latch coupling mechanism of the present disclosure. Latch coupling mechanism  250  includes latch  252  and associated locking slot  254  disposed at respective longitudinal ends of control unit housing  256  and collection canister  258 , respectively. Latch  252  and locking slot  254  function in a manner similar to the latch coupling mechanism of  FIGS. 2A and 2B . In addition, control unit housing  256  includes outwardly depending tab  260  adjacent the other longitudinal end of the control unit housing  256 . Tab  260  is received within a corresponding positioned and dimensioned tab slot  262  defined in collection canister  258 . Control unit housing  256  may be mounted to collection canister  258  by pivoting the control unit housing  256  relative to the collection canister  258  in a manner to position tab  260  within tab slot  262 . Thereafter, control unit housing  256  is pivoted about the longitudinal end containing tab  260  to insert latch  252  within locking slot  254  until the latch  252  is secured within the locking slot  254 . Release of control unit housing  256  is effected by depressing latch  252  inwardly to be released from locking slot  254 , and, thereafter, pivoting the control unit housing  256  about tab  260  to remove the tab  260  from tab slot  262 . 
       FIG. 3B  illustrates an alternate embodiment including a pair of latches  280  and associated slots  282  defined within the side walls  284 ,  286  of control unit housing  288  and collection canister  290 . In other respects, this embodiment is substantially similar to the embodiment of  FIG. 3A . 
       FIGS. 4A and 4B  illustrate an alternate embodiment of the latch coupling mechanism of the present disclosure. Latch coupling mechanism  300  incorporates a pair of tabs  302  and associated tab slots  304  at the longitudinal ends of control unit housing  306  and collection canister  308 , respectively. Tabs  302  and slots  304  may be disposed adjacent respective corners to establish a pivot axis for rotating control unit housing  306  relative to collection canister  308  during release and securement of the two components. Latch coupling mechanism  300  further includes locking latch  310  and associated locking slot  312  at the other longitudinal end of control unit housing  306  and collection canister  308 , respectively. Locking latch  310  and locking slot  312  function in a manner similar to the embodiments of  FIGS. 2A-2D . 
       FIGS. 4C and 4D  illustrate an alternate embodiment of latch coupling mechanism  350 . Control unit housing  352  and collection canister  354  include latch  356  and locking slot  358 , respectively. Collection canister  354  further includes release tab  360  adjacent locking slot  358  and a pair of relief grooves or slots  362  on each side of the locking slot  358 . Latch  356  is received within locking slot  358  when in the engaged position of collection canister  354  and control unit housing  352 . To release the components, release tab  360  may be depressed in a downward direction “m” indicated in  FIG. 4C  to cause the release tab  360  to pivot outwardly through an angular range of movement and displace locking slot  358  from latch  356 . Such movement of release tab  360  relative to collection canister  354  is facilitated by relief grooves  362 . Upon release of locking slot  358  from latch  356 , control unit housing  352  is removed from collection canister  354 . Latch coupling mechanism may further include a pair of tabs  364  and associated tab slots  366  at the longitudinal ends of control unit housing  352  and collection canister  354 , respectively. 
     Referring now to  FIG. 5 , an alternate embodiment of latch coupling mechanism  350  incorporates release tongue  368  in lieu of a release tab  360 . Release tongue  368  may be a strip, band, or section of material looped around locking slot  358 . When latch  356  is engaged with locking slot  358 , the operator may pull on tongue  368  in an outward direction thereby deforming portions of collection canister adjacent locking slot  358  as facilitated by relief grooves  362 , to permit release of the latch  356  from the slot  358 , and subsequent release of collection canister  354  from control unit housing  352 . 
       FIGS. 6A and 6B  illustrate an alternate embodiment of latch coupling mechanism  400  in an engaged and disengaged position, respectively. Control unit housing  402  includes a pair of opposed internal locking detents  404  which change position from a locked or contracted state as depicted in  FIG. 6A  to an unlocked or expanded state as depicted in  FIG. 6B  upon external contact. Collection canister  406  incorporates a pair of locking elements  407  associated with a pair of outer locking recesses  408  in opposed relation to the locking detents  404 . Locking elements  407  may be normally biased toward the radial outward position, e.g., in the direction of arrow “b” depicted in  FIG. 6B . Consequently, as control unit housing  120  is positioned over and depressed or moved in the direction of directional arrow “t” in  FIG. 6A , locking detents  404  contact locking elements  407  thereby locking locking detents  404  in a contracted position. With this arrangement, locking elements  407  are directed radially inwardly for reception with control until housing  120 . Once positioned within control until  120 , locking elements  407  are released to permit locking grips  403  to be received within locking recesses  408  to secure collection canister  406  relative to control unit housing  402 . 
     Collection canister  406  is released from control unit housing  402  by depressing or moving the control unit housing  402  in the direction of directional arrow “t” in  FIG. 6B . As the control unit housing  402  moves relative to collection canister  406 , locking detents  404  contact locking elements  407  thereby unlocking the locking detents  404  to an expanded state and directing locking elements  407  radially inwardly. Locking grips  403  are now cleared from locking recesses  408 . In this position, control unit housing  402  is free to be removed from collection canister  406  permitting disposal of the canister  406  and subsequent replacement with a new canister. 
     Referring now to  FIGS. 7A and 7B , in an alternate embodiment, latch coupling mechanism  450  includes control unit housing  452  having two locking latches  454  disposed in diametrical opposed relation. Locking latches  454  are received within corresponding locking recesses  456  of collection canister  458  when in the engaged or secured position of control unit housing  452  depicted in  FIG. 7A . Control unit housing  452  further includes release button  458  mounted to the control unit housing  452 . Release button  458  includes outer cam surfaces  460  depending outwardly from control unit housing  452 . Release button  458  is adapted for movement relative to control unit housing  452  from the position depicted in  FIG. 7A  to the position depicted in  FIG. 7B . During movement of the release button  458  to the position of  FIG. 7B , outer cam surfaces  460  engage internal surfaces  462  of collection canister  458  and bias the wall surfaces of the canister  458  radially outwardly as shown in  FIG. 7B . In this position, locking latches  454  are released from locking recesses  456  thereby permitting removal of collection canister  458 . Any means for mounting release button  458  for movement within control unit housing  452  are envisioned. 
     With reference now to  FIG. 8A , there is illustrated a body support bag  1000  for supporting at least the subatmospheric pressure mechanism  104  and at least canister  118 . As discussed, the wound therapy system  100  of the present disclosure is adapted for mounting to the body of the patient to be a self contained portal unit. In this regard, the subatmospheric pressure mechanism and canister may be at least partially carried or supported by the body support bag  1000 . The body support bag  1000  generally includes a pouch  1002  and at least one strap  1004 , in embodiments, two straps, for securing the pouch  1002  to the body of the patient. The body support bag  1000  is intended to receive and store at least subatmospheric pressure mechanism  104  and collection canister  118 . The body support bag  1000  may be worn about the waist of the patient such as with a belt loop. This is desirable in that it may reduce the length of tubing needed depending on the location of the wound. In addition, the pouch  1002  may be located adjacent the abdomen of the patient which may present a significantly enhanced ability to conceal the system. Tubing  1006  may be secured to the body with tape, straps, or the like, or, optionally, may be unsecured and disposed beneath the patient&#39;s clothing. Thus, the body support bag  1000  permits the patient to move without restrictions or limitations, and provides an entirely portable capability to the patient during wound drainage and healing. 
       FIG. 8B  illustrates an alternate embodiment of the body support bag. In accordance with this embodiment, the body support bag  1100  is adapted for mounting to the shoulder of the patient and has a pouch  1102 . In other respects, the body support bag  1100  functions in a similar manner to the body support bag of  FIG. 8A . 
     Referring now to  FIG. 9 , an alternate mechanism for coupling control unit housing  120  and collection canister  118  is illustrated. In this embodiment, subatmospheric pressure mechanism  104  includes a bayonet mount or coupling mechanism  500  for selectable releasable coupling and decoupling of control unit housing  120  and collection canister  118 . In this manner, bayonet mount  500  may facilitate the connection, disconnection, or maintenance of components of system  100 , including the replacement of collection canister  118 . In one embodiment, bayonet mount  500  has first and second coupling segments  502 ,  504  disposed substantially centered on control unit housing  120  and canister  118 , respectively. Coupling segments  502 ,  504  may be off-centered if desired. First and second coupling segments  502 ,  504  are generally cylindrical in configuration and depend from their respective component toward each other. First coupling segment  502  may define an internal dimension or diameter slightly greater than a correspondingly internal dimension or diameter of second coupling segment  504  whereby the first coupling segment  502  receives the second coupling segment  504  in the mated condition of the components. In one aspect, either coupling segment  502 ,  504  may incorporate a gasket or  0 -ring seal (not shown) whereby a substantial seal is formed when the components are coupled. Coupling segment  502  may include at least one internal bayonet projection or bayonet lug  508  depending radially inwardly relative to an axis “k” of the first coupling segment  502 . Second coupling segment  504  includes at least one correspondingly dimensioned and positioned lug retaining slot  510 . In one embodiment, a plurality of bayonet lugs  508  and corresponding retaining slots  510  are radially spaced about their respective components. Each bayonet lug  508  may be a pin, knob, ball, knot, or other protrusion transverse to longitudinal axis “k.” 
     Lug retaining slot  510  is a generally “L”, “U” or “Z” shaped recess, through-hole, groove, or the like. For example, each lug retaining slot  510  has lug receiving segment  510   a , transverse segment  510   b  and retention segment  510   c . Bayonet mount  500  further includes a spring mechanism or resilient member  512  disposed at the intersection of first and second coupling segments  502 ,  504  when mated. Spring mechanism  512  may be in the form of a resilient or elastomeric washer or disc disposed within first coupling segment  502 . Spring mechanism  512  facilitates retention of bayonet lugs  508  within retaining slots  510  by biasing the first coupling segment  502  away from the second coupling segment  504  when the coupling segments  502 ,  504  are mated as will be discussed. 
     First and second coupling segments  502 ,  504  also may include visual indicia  514  to facilitate alignment of the respective bayonet lugs  508  and retaining slots  510  of the first and second coupling segments  502 ,  504 . Such visual indicia may be arrows, dots, lines on the exterior surfaces of first and second coupling segments  502 ,  504  as depicted in  FIG. 9 . 
     As illustrated in  FIGS. 10A-10C , first coupling segment  502  is positioned over second coupling segment  504  when control unit housing  120  is aligned with canister  118 . Each bayonet lug  508  enters lug receiving segment  510   a  of each retaining slot  510  and is advanced to be aligned with transverse segment  510   b  of the lug retaining slot  510 . ( FIG. 10A ). During this movement, spring mechanism  512  is compressed as depicted in  FIG. 10B . Thereafter, first and second coupling segments  502 ,  504  are rotated relative to each other through a predetermined angular sector of rotation whereby bayonet lug  508  is adjacent retention segment  510   c . The clinician then may release at least one of the coupling segments  502 ,  504 , which, effectively causes each bayonet lug  508  to be received within retention segment  510   c  of retaining slot  510  under the bias of spring mechanism  512 . Spring mechanism  512  possesses sufficient resiliency to effectively secure bayonet lug(s)  508  within its respective retention segment(s)  510   c  of retaining slot(s)  510 .  FIG. 10C  illustrates spring mechanism  512  expanded to secure bayonet lug  508  within retention segment  510   c.    
     Removal of collection canister  118  from control unit housing  120  may be performed by advancing collection canister  118  relative to control unit housing  120  against the bias of spring mechanism  512  whereby each bayonet lug  508  traverses retention segment  510   c  to be in alignment with transverse segment  510   b . Collection canister  118  and control unit housing  120  are rotated relative to each other to cause each bayonet lug  508  to be positioned in alignment with a corresponding lug receiving segment  510   a  of retaining slot  510 . Collection canister  118  is then removed from control unit housing  120  with bayonet lug(s)  508  exiting the lug receiving segments  510   a.    
     FIGS.  11  and  12 A- 12 C illustrate an alternate embodiment of a bayonet coupling. In accordance with this embodiment, second coupling segment  600  incorporates a plurality of latches  602  to secure bayonet lugs  508 . In use, bayonet lugs  508  are aligned with recesses  604  of second coupling segment  600  to position first coupling segment  502  relative to second coupling segment  600  ( FIG. 12A ). Thereafter, first and second coupling segments  502 ,  600  are rotated relative to each other whereby bayonet lugs pass  508  pass latches  602  to be received within locking recesses  606  ( FIG. 12B ). Latches  602  are sufficiently flexible to permit passage of bayonet lugs  508 , but, return to their original position once received within locking recesses  606  ( FIG. 12C ). This mechanism may provide a more permanent connection. As an alternative, first coupling segment  502  may incorporate spring mechanism  512  which may be compressed to displace bayonet lugs  508  from locking recesses  606  thereby permitting relative rotational movement of the first and second coupling segments  502 ,  600  and removal of collection canister  118  from control unit housing  120 . 
     Bayonet mount  500  may be constructed as shown in the exemplary embodiments above, or in reverse so that coupling segment  502  is on canister  118  and coupling segment  504 ,  600  is on control unit housing  120 . Further, the number, length, angle, and size of bayonet lug(s)  508  of coupling segment  502  may vary and accordingly, retaining slot  510  of coupling segment  504  will correspond to the size, number, and configuration of projection(s)  508  so that control unit housing  120  and canister  118  may be releasably joined together. 
     Referring now to  FIG. 13  another embodiment of releasably connecting collection canister  118  and control unit housing  120  of subatmospheric pressure mechanism  104  is illustrated. Fastener mechanism  640  includes strap  642  and catch  644 . Strap  642  may be of a predetermined length sufficient to wrap around housing  120  and firmly hold housing  120  to canister  118 . Strap  642  may also be made of material having an elastic component in order for strap  642  to stretch around housing  120  and join the two components. In the alternative, strap  642  may be substantially rigid and formed of steel, titanium, a polymeric material or the like. Strap  642  includes closed looped end  643 . Looped end  643  is passed around canister  118  and housing  120  to securely and firmly connect housing  120  to canister  118 . Catch  644  are used to secure strap  642  to housing  120 . In the current embodiment, catch  644  is in the form of indentations substantially parallel to the path of strap  642  for holding strap  642  on housing  120 . To release, the operator pulls strap  642  away from housing  120 . In embodiments, strap  642  has sufficient elasticity that it may catch on housing  120  without the use of catch  644 . 
       FIG. 14  illustrates another embodiment of canister  118  having strap  642  and catch  644 . Strap  642  is affixed to a side of canister  118  and catch  644  is disposed on an opposite side of canister  118 . Catch  644  may be a button, knob, hook, clasp, bar, or other protrusion capable of securing strap  642 . In embodiments, catch  644  may be one half of a fixation element such as a hook and loop fastener. To join housing  120  and canister  118 , the operator passes strap  642  over housing  120  and secures it with catch  644 . 
       FIGS. 15A and 15B  illustrate another embodiment of canister  118  having an alternative placement of straps  642  and an alternate catch  644  than  FIGS. 13 and 14 . Canister  118  includes strap  642  anchored on canister  118  to form closed looped end  643 . Housing  120  includes catch  644  in the form of a bar, but other protrusions as described above may be used. Strap  642  is placed around catch  644  thus preventing strap  642  from moving and releasably connecting canister  118  with housing  120 . The operator may then release housing  120  by freeing strap  642  from catch  644 . 
     In other embodiments, the fastener mechanism may include complementary joining members disposed around the periphery of housing  120  and canister  118 , examples of which are shown in  FIGS. 16-21 .  FIG. 16A  illustrates housing  120  of control unit  116  and collection canister  118  releasably connected by zipper  650 . Zipper  650  includes first teeth assembly  651 , second teeth assembly  652 , and slider  653 . First and second teeth assemblies  651  and  652  are disposed on housing  120  and canister  118 , respectively. Slider  653  may be attached to either first or second teeth assemblies  651  or  652 . As known to those skilled in the art, slider  653  includes wedges that combine the hooks and hollows of first and second teeth assemblies  651  and  652  in order to fasten first and second teeth assemblies  651  and  652  together.  FIG. 16B  illustrates use of hook and loop fastener  654 . Fastener  654  includes hook  655  and loop  656  material, each disposed on one of housing  120  and canister  118 . As housing  120  is brought in contact with canister  118 , the pressure exerted causes hooks  655  to entangle loops  656  to form a bond strong enough to hold housing  120  and canister  118  together. By exerting pressure to separate housing  120  from canister  118 , hook and loop bonds are broken a few at a time along the length of fastener  654  in order to remove housing  120  from canister  118 . 
       FIG. 17  illustrates use of door fastener  658 . Door fastener  658  includes door  657 . Door  657  is unfastened so that housing  120  may be placed on top of canister  118 . Once placed together, door  657  is closed and locked in place. In embodiments, door  657  is located on canister  118 . In other embodiments, door  657  is located on housing  120 . It is envisioned that more than one door  657  may be used to securely engage canister  118  with housing  120 . 
       FIG. 18  illustrates use of screw fastener  660 . Screw fastener  660  includes thumbscrews  662  through housing  120  and receiving slots  666  in canister  118 . Thumbscrew  662  includes gripping head  663  and threaded body  664 . Head  663  may include ridged sides  665  for engaging the operator&#39;s fingers for better control of thumbscrew  662 . The operator twists head  663  of thumbscrew  662  until threaded body  664  is firmly interlocked with slot  666  of canister  118 . To release, thumbscrew  662  is twisted in the opposite direction. In embodiments, head  663  of thumbscrew  662  may be slotted for receiving a screwdriver. 
       FIG. 19  illustrates use of ring fastener  668 . Ring  669  is disposed around canister  118  and gasket  670  on housing  120 . Ring  669  may be fixed at one end to canister  118  or may be independently associated with canister  118 . As housing  120  is placed on canister  118  gasket  670  deforms and compresses. Ring  669  may then be slidingly engaged around both housing  120  and canister  118  utilizing gasket  670  as a securement point. In embodiments, ring fastener  668  is constructed in reverse so that sliding ring  669  is disposed on housing  120  and gasket  670  on canister  118 . 
       FIGS. 20A and 20B  illustrate use of friction fit fastener  672 .  FIG. 20A  illustrates housing  120  having angled edges  674  and canister  118  having complementary angled edges  676 . As housing  120  is placed on canister  118  angled edges  674  of housing  120  slide over angled edges  676  of canister  118  slightly displacing edges  674  causing edges  674  to grip edges  676 , thus holding housing  120  and canister  118  together. In embodiments, a gasket may be used between housing  120  and canister  118  to aid in removably sealing the two components together.  FIG. 20B  utilizes groove  678  in housing  120  and tongue  680  on canister  118 . Tongue  680  is sized comparably to groove  678  so that as tongue  680  is inserted into groove  678  they frictionally fit together thus securing housing  120  with canister  118 . In embodiments, friction fit fastener  672  is constructed in reverse, such that tongue  680  is located on housing  120  and groove  678  in canister  118 . 
       FIGS. 21A and 21D  illustrate use of snap fastener  682  to facilitate connection between housing  120  and canister  118 . Snap fastener  682  includes bar  684  having protrusions  686 . One end of bar  684  is pivotably connected to housing  120 . Indentations  688  are positioned on canister  118  such that when housing  120  is positioned on canister  118  and bar  684  pivoted towards canister  118 , protrusions  686  and indentations  688  align and snap fit together thus joining canister  118  and housing  120 . To release, the operator pulls bar  684  away from canister  118  thus disengaging protrusions  686  from indentations  688 . In embodiments, snap fastener  682  is constructed in reverse, such that indentations  688  are located on housing  120  and bar  684  on canister  118 . 
     In embodiments, the fastener mechanism comprises spring-loaded button fastener  690 . Examples are included in  FIGS. 22-24 . In  FIGS. 22A and 22B , housing  120  includes spring-loaded buttons  690 . Button  690  includes button  692  and spring  694 . Spring-loaded button  690   a  is shown in its unbiased state, while button  690   b  is shown in a biased position. Button  692  generally lies at an angle with the top portion protruding farther out from housing  120  than the bottom portion so that as housing  120  slides onto canister  118 , buttons  692  compress against canister  118 , returning to their biased position when reaching opening  696  in canister  118 . The slope of button  692  also prevents housing  120  from slidingly detaching from canister  118  unless the operator presses button  692  in towards canister  118 . In embodiments, buttons  692  are placed on the longer sides of canister  118  close to one end so that the operator may press both buttons  692  with one hand. 
       FIG. 23  illustrates another embodiment for fastening housing  120  and canister  118  using spring-loaded button fastener  690  and pivot point  698 . Spring-loaded button fastener  690  is placed on one end of housing  120  and the other end is permanently or removably coupled to canister  118  at pivot point  698 . The operator pivots housing  120  down towards canister  118  to engage spring-loaded button fastener  690 . To disengage, the operator presses button  692  and pivots housing  120  back up. In embodiments, subatmospheric pressure mechanism  104  is a disposable unit. In other embodiments, canister  118  can be used with a disposable collection bag (not shown) placed therein.  FIG. 24  illustrates another embodiment using spring-loaded button fastener  690 . Gasket  670  is also utilized and includes grooved surface  671  which deforms and sticks down to canister  118  when housing  120  is placed on canister  118  and spring-loaded button fastener  690  is engaged. 
     In yet other embodiments, as illustrated in  FIGS. 25 and 26 , the fastener mechanism includes sliding mechanism  700 . Sliding mechanism includes rail  702  and track  704 , one of each being disposed on housing  120  and canister  118 . Housing  120  and canister  118  are engaged by placing one end of housing  120  adjacent one end of canister  118  such that rail  702  and track  704  align. Housing  120  may then slide across canister  118  to a closed position. An additional fastening mechanism may be used in conjunction with mechanism  700 , such as spring-loaded buttons  690  as illustrated in  FIG. 25  and door  658  in  FIG. 26 . 
     In other embodiments, the fastener mechanism may include spring-assisted clips  706 . Spring-assisted clips  706  include hook element  708 , grab element  710 , and springs  712 .  FIGS. 27A and 27B  illustrate alternate embodiments utilizing clips  706 . Hook element  708  is disposed on housing  120  and springs  712  are placed adjacent to each hook element  708 . Grab element  710  is located on canister  118  and is complementary to hook element  708 . Housing  120  is placed on top of canister  118  and pressed down, so that springs  712  compress against canister  118 . Housing  120  is slid onto canister  118  so that hook element  708  catches grab element  710 . As the operator releases pressure on housing  120 , springs  712  spring up and housing  120  remains connected to canister  118 . To disconnect, the operator presses back down on housing  120  so that hook and grab elements  708  and  710  disconnect. The operator then slides housing  120  away from canister  118 . Other embodiments, such as  FIG. 28 , illustrate alternate placement and types of hook and grab elements  708  and  710 , respectively. 
       FIGS. 29A and 29B  illustrate use of movable clip fastener  712  to releasably join housing  120  with canister  118 . Clip fastener  712  includes fixed grab element  714 , movable hook element  716 , and gasket  718 . Housing  120  includes movable hook element  716  and canister  118  includes fixed grab element  714  and gasket  718 . As housing  120  is placed on canister  118 , gasket  718  deforms and seals canister  118 . Movable hook elements  716  are brought down towards canister  118  and hooked on fixed grab elements  714  thus connecting housing  120  and canister  118 . To release, the operator releases movable hook element  716  from fixed grab element  714 . The operator may also first press down on housing  120  to compress gasket  718  thus creating room to release movable hook element  716  from fixed grab element  714 . 
     Referring now to  FIGS. 30A-30C , other embodiments of releasably connecting collection canister  118  and control unit housing  120  are illustrated. Housing  120  includes switch  829  and at least one electromagnet  831  disposed along the periphery of housing  120 . Switch  829  may be a button, knob, dial, or other adjuster capable of activating and/or de-activating electromagnet  831  by way of control circuitry (not shown). Switch  829  may be manually actuated, or, in the alternative, may be automatically actuated upon mounting of some of the components of the subatmospheric pressure mechanisms  104 . The control circuitry recognizes changes in state of switch  829  and activates or de-activates the magnetic field of electromagnet  831  by altering the flow of current from a power source  168  (not shown). The magnetic field of electromagnet  831  can be manipulated over a wide range by controlling the amount of electric current from the power source. 
     Collection canister  118  includes magnetic or ferromagnetic material which may be disposed within or adjacent to upper portion  835  of canister  118 . Magnetic material  840  may be a permanent magnet or metal capable of being attracted by the magnetic field created by electromagnet  831  of housing  120  of control unit  116 . Such materials include nickel, iron, cobalt, their alloys, and the like. Other materials, within the purview of those skilled in the art, containing detectable magnetic properties may be used. Magnetic material  840  may be placed anywhere on canister  118 . For example,  FIG. 30A  shows magnet material  840  in the form of an annular magnet disposed within the side walls  841  and  842  of canister  118 .  FIG. 30B  shows magnetic material  840  disposed on top wall  843 .  FIG. 30C  shows upper portion  835  of canister  118  made of magnetic material  840  and thus, a portion of canister  118  itself is magnet  840 . 
     Housing  120  of control unit  116  is releasably connected to collection canister  118 . Housing  120  of control unit  116  may be placed partially within canister  118  such as shown in  FIG. 30A . Control unit housing  120  is supported by supports  844  at least partially disposed within canister  118 . Control unit housing  120  may also be placed on top of canister  118  as shown in  FIG. 30B .  FIG. 30B  also contains a lip or seal  825  to aid in aligning housing  120  of control unit  116  on canister  118  and to tightly close or seal canister  118 . 
     When housing  120  of control unit  116  and canister  118  are mounted to each other, electromagnet  831  of control unit housing  120  and magnetic material  840  of canister  118  are substantially aligned or positioned such that magnets  831  and  840  are capable of attracting each other. Switch  829  may be indented within housing  120  to prevent inadvertent activation. In embodiments, such as  FIG. 30C , two switches  829  are utilized thus making it more difficult to mistakenly engage both switches  829  and disconnect the components. Any number of magnets may be disposed around housing  120  of control unit  116  and controlled by switch  829 , such as the configurations shown in  FIGS. 30D-30F . As indicated hereinabove, switch  829  may be manually activated and may, e.g., be mounted to the exterior of either housing  120  or canister  118 . 
     Alternatively,  FIG. 31  illustrates use of a permanent magnet  931  instead of an electromagnet in control unit housing  120 . The distance created between magnets  931  and  940  or change in dipole moments breaks the magnetic field and frees control unit housing  120  from canister  118 . 
     To assemble the control unit housing  120  and the canister  118 , the housing  120  and canister  118  are aligned and joined together by activating the magnetic field of electromagnet  831  by switch  829  of  FIGS. 30A-30C  (or the magnetic field of permanent magnets  931  and  940  of  FIG. 31 ). Alternatively, housing  120  of control unit  116  and canister  118  may have complimentary sensors for detecting attachment which in turn signal control circuitry to activate a power source. Control unit housing  120  and canister  118  remain coupled until switch  829  is triggered and electromagnet  831  de-activated. 
     While the disclosure has been illustrated and described, it is not intended to be limited to the details shown, since various modifications and substitutions can be made without departing in any way from the spirit of the present disclosure. As such, further modifications and equivalents of the invention herein disclosed can occur to persons skilled in the art, and all such modifications and equivalents are believed to be within the spirit and scope of the disclosure as defined by the following claims.