Abstract:
A negative pressure bandage is formed in a two chamber configuration having a lower chamber from which fluids and exudates are collected from an open wound on the patient and an upper chamber that is used to store the collected fluids and exudates removed by an application of a vacuum to the lower chamber. An impermeable layer separates the upper and lower chambers to keep the wound dry and promote healing. A vacuum port interconnects a fluid collection member located in the lower chamber with the upper chamber to allow the application of a vacuum that collects and removes fluids and exudates from the lower chamber. The vacuum pump can be remote and attached to the bandage by tubing or be incorporated into the bandage to provide a self-contained negative pressure bandage. An absorptive pad can be located in the upper chamber to collect and gel the collected fluids.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to negative pressure bandages operable to remove exudates and fluids from a wound and, more particularly, to a bandage structure that has a lower chamber for collecting the exudates and fluid for removal to a secondary bladder above the collection chamber, but within the structure of the bandage. 
     BACKGROUND OF THE INVENTION 
     Negative pressure therapy has been utilized for the treatment of a variety of wounds by medical practitioners. Conventional negative pressure bandages are generally large in size and often require the use of complicated equipment such as suction pumps, vacuum pumps and complex electronic controllers to apply a negative pressure within the bandage to draw exudates and fluids away from the wound to a remote collection container. Typically, negative pressure therapy involves other associated equipment, such as the exudates/fluid collection canisters, liquid transporting conduits, and pressure regulators/transducers/sensors. As a result, negative pressure bandages and related equipment tends to be bulky and relatively costly. Such complexity typically requires professional placement of the bandage and connection to the pump and collection canister, followed by consistent, regular patient supervision and monitoring. Generally, negative pressure bandages are applied for approximately two days, at which time the bandage must be removed and replaced by professional technicians. 
     The rising costs of healthcare and of medical devices, such as negative pressure bandages, provide incentive to develop less expensive equipment, and procedures that are more easily utilized to reduce the costs associated with the use of sue therapy while improving on the effectiveness of the therapy. Simplification of the procedures and the equipment can allow in-home use of such therapies with a minimum of professional supervision and monitoring of the patients. Furthermore, patients continue to demand devices that are more easily portable to allow travel and mobility while utilizing the therapy. 
     In U.S. Pat. No. 7,615,036, granted to Ashok Joshi, et al on Nov. 10, 2009, a negative pressure bandage is disclosed in which the bandage has a housing that is sealed to the body surface of the patient and defines a liquid retention chamber coupled to a vacuum source to apply a negative pressure on the liquid retention chamber so that the exudates and fluids are drawn into an absorptive material within the liquid retention chamber. This liquid retention chamber is located adjacent to the wound from which the exudates and fluids are removed. 
     Improvements to negative pressure wound therapy devices can be found in U.S. Patent Publication No. 2009/0299251 of John Buan published on Dec. 3, 2009, to enhance the sealing of the bandage to the body surface of the patient. In this negative pressure wound therapy device, a vacuum is applied to a collection chamber in which an absorptive pad is disposed to collect the exudates and fluids drawn away from the wound by the vacuum (negative pressure). To enhance the connection of the tubing extending between the vacuum pump and the negative pressure therapy device, an extended length connector is disclosed, which will accommodate connection when ACE wrap or other coverings are applied to the exterior of the bandage. 
     In U.S. Pat. No. 7,361,184, granted on Apr. 22, 2008, to Ashok Joshi, an attempt to provide a self-contained negative pressure wound therapy device is provided so that the device does not require connection to a remote vacuum source. In this negative pressure wound dressing, an absorptive pad is also disposed in the fluid collection chamber, which is located adjacent the wound, the negative pressure drawing the exudates and fluids away from the wound into the absorptive pad. Several early embodiments of negative pressure bandages can be found in U.S. Pat. No. 5,636,643, granted to Louis Argenta, et al on Jun. 10, 1997, all of which, however, utilize a single chamber configuration in which a vacuum is applied to the fluid collection chamber and the exudates and fluid is drawn away through tubing to a remote pump and fluid retention chamber. 
     A micropump system provides the vacuum source for the negative pressure bandage disclosed in U.S. Patent Publication No. 2009/0264807 filed by Kurt Haggstrom and published on Oct. 22, 2009. This negative pressure dressing is also a single chamber configuration with an absorptive pad placed in contact with the wound while the micropump draws the exudates and fluids from the wound site into the absorptive pad. The micropump can be reusable or disposable. The outer housing layer of the bandage is provided with an opening that enables the absorptive pad to be removed and replaced on a periodic basis. 
     It would be desirable to provide a self-contained negative pressure bandage to centralize the collection and retention of exudates and fluid from a wound in a manner that removes the exudates and fluids away from the wound site without requiring transportation thereof to a remote retention chamber. 
     SUMMARY OF THE INVENTION 
     It is an object of this invention to overcome the disadvantages of the prior art by providing a two chamber negative pressure bandage in which the collected exudates are stored in the upper chamber. 
     It is another object of this invention to separate the first chamber in which exudates are removed from the wound by an application of a vacuum from a second chamber in which the exudates are stored by an impervious layer. 
     It is a feature of this invention that the wound is kept dry by the removal of the exudates and fluids to the second chamber. 
     It is an advantage of this invention that healing of the wound is promoted. 
     It is another advantage of this invention that the disposal of the collected exudates is accomplished with the disposal of the bandage. 
     It is another feature of this invention that the vacuum pump can be incorporated into the negative pressure bandage and disposed with the bandage and the collected exudates. 
     It is still another feature of this invention that a fluid collection member is disposed within the lower chamber between the wound contact member and the impermeable layer to collect fluids and exudates from the wound. 
     It is yet another feature of this invention that the upper chamber can be provided with vertical structure to prevent the upper chamber from collapsing onto the vacuum port due to the application of the vacuum through the upper chamber. 
     It is still another feature of this invention that the upper chamber can be provided with an adsorptive pad to collect and gel the fluids and exudates removed from the lower chamber. 
     It is still a further object of this invention to provide a negative pressure bandage utilizing a two chamber configuration, which is durable in construction, inexpensive of manufacture, carefree of maintenance, facile in assemblage, and simple and effective in use. 
     These and other objects, features and advantages are accomplished according to the instant invention by providing a negative pressure bandage formed in a two chamber configuration having a lower chamber from which fluids and exudates are collected from an open wound on the patient and an upper chamber that is used to store the collected fluids and exudates removed by an application of a vacuum to the lower chamber. An impermeable layer separates the upper and lower chambers to keep the wound dry and promote healing. A vacuum port interconnects a fluid collection member located in the lower chamber with the upper chamber to allow the application of a vacuum that collects and removes fluids and exudates from the lower chamber. The vacuum pump can be remote and attached to the bandage by tubing or be incorporated into the bandage to provide a self-contained negative pressure bandage. An absorptive pad can be located in the upper chamber to collect and gel the collected fluids. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other objects, features, and advantages of the invention will appear more fully hereinafter from a consideration of the detailed description that follows, in conjunction with the accompanying sheets of drawings. It is to be expressly understood, however, that the drawings are for illustrative purposes and are not to be construed as defining the limits of the invention. 
         FIG. 1  is a top plan view of a negative pressure bandage incorporating the principles of the instant invention, the absorptive pack in the fluid retention chamber and the fluid collection apparatus in the fluid collection chamber being shown in phantom; 
         FIG. 2  is a cross-sectional view of the negative pressure bandage corresponding to lines  2 - 2  of  FIG. 1  to show the configuration thereof with the lower fluid collection chamber and the upper fluid retention chamber; 
         FIG. 3  is a top plan view of a second embodiment of a negative pressure bandage incorporating the principles of the instant invention, the absorptive pack in the fluid retention chamber being shown in phantom; 
         FIG. 4  is a cross-sectional view of the negative pressure bandage corresponding to lines  4 - 4  of  FIG. 2  to show the configuration thereof with the lower fluid collection chamber and the upper fluid retention chamber; 
         FIG. 5  is a top plan view of a third embodiment of a negative pressure bandage incorporating the principles of the instant invention, the fluid collection apparatus in the fluid collection chamber and the structural supports for the fluid retention chamber being shown in phantom; 
         FIG. 6  is a cross-sectional view of the negative pressure bandage corresponding to lines  6 - 6  of  FIG. 5  to show the configuration thereof with the lower fluid collection chamber and the upper fluid retention chamber having structural supports; 
         FIG. 7  is an enlarged cross-sectional view of the negative pressure bandage as shown in  FIGS. 2 and 4  to depict the operation thereof; 
         FIG. 8  is a top plan view of a fourth embodiment of a negative pressure bandage utilizing a micropump to provide a vacuum source to draw the exudates and fluids from the fluid collection apparatus into the upper fluid retention chamber, the absorptive pack and the micropump in the fluid retention chamber being shown in phantom; 
         FIG. 9  is a cross-sectional view of the negative pressure bandage corresponding to lines  9 - 9  of  FIG. 8  to show the configuration thereof with the lower fluid collection chamber and the upper fluid retention chamber; 
         FIG. 10  is a top plan view of a fifth embodiment of a negative pressure bandage similar to that of  FIG. 8 , but providing a recirculation through the fluid collection apparatus, the absorptive pack in the fluid retention chamber being shown in phantom; 
         FIG. 11  is a cross-sectional view of the negative pressure bandage corresponding to lines  11 - 11  of  FIG. 10  to show the configuration thereof with the lower fluid collection chamber and the upper fluid retention chamber; 
         FIG. 12  is a top plan view of a sixth embodiment of a negative pressure bandage providing a removal of the fluids from the wound at the lower chamber through a remote pump and the discharge of the collected fluids from the pump into the upper storage chamber of the bandage; and 
         FIG. 13  is a cross-sectional view of the negative pressure bandage corresponding to lines  13 - 13  of  FIG. 12  to show the configuration thereof. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings, a negative pressure bandage incorporating the principles of the instant invention can best be seen. The negative pressure bandage  10  has an outer housing  12  that is exposed outwardly from the patient when the bandage  10  is applied to an open wound to remove the exudates and fluids therefrom when connected to a conventional vacuum source (not shown). The outer housing  12  can be formed in any suitable shape, including an oval shape as shown in  FIG. 1  or a rectangular shape as depicted in  FIG. 3 . The vacuum source (not shown) is typically a small pump that is worn by the patient remotely from the bandage  10  to apply a vacuum to the bandage  10  and affect the removal of exudates and fluids from the wound site through conventional tubing (not shown) that is connected to the bandage  10 , as will be described in greater detail below. 
     The bandage  10  has a wound contact panel  15  below the outer housing  12 . The wound contact panel  15  can be a layer of gauze, but is preferably a material that will reduce adhesion of the wound contact panel  15  to the underlying wound tissue, such as a silver coated mesh. Surrounding the wound contact panel  15  is a sealing portion  13  of the housing  12  on the underlying surface of the housing  12  which is formed with a suitable adhesive (not shown) and a removable backing member  14  so that the removal of the backing  14  exposes the sealing portion  13  for contact with the body portion of the patient surrounding the wound. 
     An intermediate fluid impermeable housing member  20  lies between the outer housing  12  and the wound contact panel  13  to separate the outer housing member  12  from the wound contact panel  15  and define separate chambers  30 ,  40  above and below the intermediate housing member  20 . The liquid collection chamber  30  below the intermediate housing panel  20  functions to collect exudates and fluids from the wound being treated, while the liquid retention chamber  40  above the intermediate housing member  20  functions to retain the exudates and fluids collected from the wound. 
     The outer housing member  12  has a vacuum port  25  formed at one end thereof. The vacuum port  25  can be on any appropriate shape or size, but has connected thereto an adaptor  26  for the attachment of tubing to connect the bandage  10  to a remote, external pump (not shown) to apply a vacuum, or negative pressure, of approximately 75 to 125 mmHg to the liquid retention chamber. Internally of the vacuum port  25 , a hydrophobic, or fluid impermeable, filter  28  is attached to the vacuum port  25  to prevent fluids from passing through the vacuum port  25  while negative pressure is applied to the adaptor  26 . One material that can prevent the passage of fluid through the vacuum port  25  while allowing a vacuum to be applied to the fluid retention chamber is GORE-TEX® material. 
     Preferably, a gelling agent, such as sodium carboxy methyl cellulose, and medicaments, such as an antimicrobial agent, will be added into the liquid retention chamber  40  to convert liquids into a gel-like substance and to prevent the growth of bacterial therein. Optionally, the liquid retention chamber  40  could house an absorptive pad  45 , which can contain the gelling agent and medicaments, and provide a structure for the retention of the exudates and fluids within the liquid retention chamber  40 . The absorptive pad  45  would be capable of absorbing exudates and fluids transferred from the wound, as will be described in greater detail below, while continuing to allow a vacuum to be applied to the liquid retention chamber  40  to draw the exudates and fluids from the wound site. The absorptive pad  45  may be a sponge, gauze, or super-absorbent materials including super-absorbent or combinations thereof. 
     The intermediate housing member  20  is formed with a connective port  35  at one end of the intermediate housing member  20 , preferably in opposition to the vacuum port  25  so that one port is at one end of the bandage  10  while the other port is at the opposite end, to allow flow communication between the liquid retention chamber  40  and the liquid collection chamber  30 . The connective port  35  is connected to a fluid collection member  37  that the vacuum applied to the fluid retention chamber  40  through the vacuum port  25  is communicated to the fluid collection chamber  30  through the fluid collection member  37 . 
     The fluid collection member  37  is preferably a hollow device having a plurality of openings therein to allow exudates and fluids to enter into the interior of the fluid collection member  37  as a result of the applied vacuum communicated thereto through the connective port  35 . The fluid collection member  37  can be any suitable shape, such as an elongated, linear tube as shown in  FIGS. 1 ,  2  and  4 , or an oval member as depicted in  FIGS. 5 and 6 , depending on the size and shape of the wound to be treated. The fluid collection member  37  is preferably positioned above the wound contact panel  15  so that exudates and fluids will be drawn away from the wound through the wound contact panel  15  and into the fluid collection member  37  to be conveyed through the connective port into the fluid retention chamber  40 . In this manner, the exudates and fluids are not retained within the fluid collection chamber  30  in proximity to the wound, allowing the wound to heal quicker. 
     Since the outer housing member  12  and the intermediate housing member  20  are flexible in nature, the fluid retention chamber  40 , as is shown in  FIGS. 5 and 6 , may require vertical structure, such as pleats  42  or stays, within the liquid retention chamber  40  so that the fluid retention chamber  40  does not collapse onto the vacuum port  25  or the connective port  35  and prevent the application of the negative pressure from the vacuum port  25  to the fluid collection member  37 . In such as structure, the gelling agent and/or the absorptive pad  45  would be located between, or perhaps beneath, each of the pleats  42  so that the exudates and fluids drawn from the fluid collection chamber  30  are distributed throughout the fluid retention chamber  40 . 
     The general operation of the bandage  10  is depicted in  FIG. 7 . The adaptor  28  is connected through tubing (not shown) to a vacuum source (not shown) to apply a negative pressure through the vacuum port  25  to the fluid retention chamber  40 . The vacuum is applied to the fluid collection member  37  in the fluid collection chamber  30  through the open connective port  35  to draw exudates and fluids from the wound site up through the wound contact panel  15  into the interior of the fluid collection member  37 . The vacuum, or negative pressure, pulls the exudates and fluids up through the connective port  35  into the fluid retention chamber  40  toward the vacuum port  25 . The hydrophobic or fluid impermeable filter  28  rejects the passage of exudates and fluids through the vacuum port, as is represented by line  49 . The exudates and fluids interact with the gelling agent and or become absorbed into the absorptive pad  45  to accumulate within the fluid retention chamber. 
     Preferably, the bandages will come in a variety of sizes and capacities. One particular embodiment would provide for a capacity of approximately 50 cc of exudates and fluids within the fluid retention chamber  40  to provide approximately two days of negative pressure wound therapy for the patient before the bandage would need to be changed. Obviously, certain wound conditions would require larger bandages with greater capacities to accommodate two days of negative pressure wound therapy. Thus, a professional technician would only need to visit, or the patient would only need to change the bandage, every other day. 
     One skilled in the art will recognize that the application of a negative pressure to the bandage  10  will require a good seal between the sealing portion  13  of the bandage  10  and the skin of the patient around the wound site. To assure an adequate seal around the bandage  10 , a stomahesive paste is preferably applied to the sealing portion  13  of the bandage before being affixed to the body portion of the patient. In some instances, a wrapping, such as an ACE wrap, around the bandage  10  is helpful in retaining the bandage in place with a sealed connection with the body portion of the patient. 
     An alternative arrangement of the bandage  10  is depicted in  FIGS. 8-11  in which the pump system  50  supplying the vacuum to the fluid collection member  37  is housed within the fluid retention chamber  40 . The pump system  50  includes a miniature pump or micropump  52 , such as the micropump manufactured by Piab Vacuum Products in Hingham, Mass., having a length ranging from about 1 to 3 inches and a relatively small diameter, preferably, no greater than about one inch. However, the micropump  52  may be any type of pump that is biocompatible and can maintain adequate and therapeutic vacuum levels in the range of 75 to 125 mmHg. Preferably, the micropump  52  is mounted on the connective port  35  to apply negative pressure directly to the fluid collection member  37  positioned within the fluid collection chamber  30 . The micropump  52  is preferably disposable and contains a power source, such as an internal self-contained battery source, that will enable the micropump  52  to be operative for at least 48 hours until the bandage is to be replaced. A pressure sensor or transducer to monitor pressure adjacent the micropump  52 , or selected locations displaced from the micropump  52 , and a control mechanism may also be needed and could be mounted on the outer housing member  12  where the output therefrom would be visible to the patient. 
     The output of the micropump  52  may be increased or decreased, or initiated or discontinued, as enabled by the control mechanism. The pressure sensor would also provide information to assist in detecting a leak in the bandage  10  if the optimal negative pressure is not achieved. The control mechanism may also have an alarm such as a visual, audio or tactile sensory alarm to indicate to the user when specific conditions have been met, such as a loss of vacuum. 
     In  FIGS. 8 and 9 , an outlet vent  55  may be needed to allow the micropump  52  to generate the requisite vacuum for application to the fluid collection member  37 . In this embodiment, the hydrophobic or fluid impermeable filter  28  would be associated with the vent port  55  to retain the exudates and fluids within the fluid retention chamber  40 . Furthermore, the vent port  55  could incorporate a pressure relief valve that will retain the negative pressure within the fluid collection member  37 . Otherwise, the bandage  10  operates as noted above with the exudates and fluids being drawn from the fluid collection chamber  30  via the fluid collection member  37  and the micropump  52  into the fluid retention chamber  40 . Once in the fluid retention chamber  40 , the exudates and fluids will react with the gelling agent or be absorbed into the absorptive pad  45  so as to be accumulated within the fluid retention chamber  40 . The hydrophobic, or fluid impermeable, filter  28  prevents the exudates and fluids from leaving the fluid retention chamber  40  through the vent port  55 . Preferably, the bandage  10  will be removed and properly discarded every other day and replaced with a fresh bandage  10  having a new micropump  52  and fresh battery. 
     Alternatively, as is depicted in  FIGS. 10 and 11 , the vent port  55  is placed into the opposing end of the intermediate housing member  20  from the connective port  35  and the associated micropump  52 . The hydrophobic, or fluid impermeable, filter  28  would be associated with the vent port  55  to prevent exudates and fluids accumulating in the fluid retention chamber  40  from returning to the fluid collection chamber  30 . The micropump  52  would draw a vacuum on the fluid collection member  37  while circulating gases, such as air back into the fluid collection chamber  30  to facilitate the movement of exudates and fluids through the fluid collection member  37  into the fluid retention chamber  40 , where the gelling agent and/or the absorptive pad  45  would help to retain the exudates and fluids within the fluid retention chamber  40 . 
     A further alternative arrangement of the bandage  10  is depicted in  FIGS. 12 and 13  in which the vacuum pump  60  supplying the vacuum to the fluid collection member  37  is located remotely from the bandage  10 , such as being mounted on the patient&#39;s belt. The pump  60  is attached via a first tubing member  61  and an adapter  26  to the connective port  35  to apply negative pressure directly to the fluid collection member  37  positioned within the lower fluid collection chamber  30 . The pump  60  is typically battery powered to enable the pump  60  to be operative for at least 48 hours until the bandage is to be replaced. The conventional pump  60  is operable to apply a constant vacuum to the fluid collection member and will normally have a display to reflect the operation of the pump  60 . 
     The fluids and exudates collected by the fluid collection member  37  and travel to the pump  60  through the first tubing member  61  and then is discharged from the pump  60  through a second tubing member  63  that is connected to a second connective port  65  via a second adapter  26  to deliver the collected fluids and exudates into the upper storage chamber  40 . As described above, the upper storage chamber  40  can be provided with an absorptive pad  45  to absorb and gel the collected fluids. Thus, the fluids and exudates collected from the lower chamber are stored in the upper chamber separated by the impermeable intermediate housing member  20 . 
     As depicted in the embodiment of  FIGS. 8 and 9 , an outlet vent  55  may be needed to allow the release of air from the upper chamber  40 . Preferably, a hydrophobic or fluid impermeable filter  28  would be associated with the vent port  55  to retain the exudates and fluids within the fluid retention chamber  40 . Furthermore, the vent port  55  could incorporate a pressure relief valve that will allow a predetermined amount of pressure to be retained within the upper storage chamber  40 . The hydrophobic, or fluid impermeable, filter  28  prevents the exudates and fluids from leaving the fluid retention chamber  40  through the vent port  55 . Preferably, the bandage  10  will be removed and properly discarded every other day, along with the tubing, with a fresh bandage applied to the wound and fresh tubing interconnecting the pump  60  and the adapters  26  in the proper manner. 
     The invention of this application has been described above both generically and with regard to specific embodiments. Although the invention has been set forth in what is believed to be the preferred embodiments, a wide variety of alternatives known to those of skill in the art can be selected within the generic disclosure. It will be understood that changes in the details, materials, steps and arrangements of parts which have been described and illustrated to explain the nature of the invention will occur to and may be made by those skilled in the art upon a reading of this disclosure within the principles and scope of the invention. The foregoing description illustrates the preferred embodiment of the invention; however, concepts, as based upon the description, may be employed in other embodiments without departing from the scope of the invention.