Abstract:
A chest seal for treating an open pneumothorax that is low profile and thus unobtrusive so that the chest seal can be effectively maintained in position to seal a chest wound while allowing the pleural cavity to vent.

Description:
BACKGROUND OF THE INVENTION 
     When an individual suffers a puncture wound to the chest, such as from being shot or stabbed, the wound often penetrates into the chest cavity so as to puncture the parietal pleura, visceral pleura, and sometimes even the lungs. Such a wound allows air to flow freely into the chest cavity and pleural space. 
     An open pneumothorax is a condition wherein air penetrates into the pleural space between the lung(s) and the chest wall through a wound hole. When a patient has an open pneumothorax, the normal mechanism by which the lungs expand is inhibited or lost. Consequently, the affected lung will not expand when the patient inhales and respiratory distress ensues. The severity of an open pneumothorax can be minimized by sealing the open wound. However, already trapped air is not allowed to escape from the pleural space. 
     U.S. Pat. No. 5,478,333 discloses a chest seal having a duck bill valve that prevents air from entering the pleural space while allowing already trapped air to escape. The duck bill valve is attached to a cylindrical section of duct that projects from the body attached flange of the chest seal. The cylindrical section allows the chest seal to be used as a conduit for a catheter if a severe tension pneumothorax or collapsed lung is to be treated with an invasive procedure and/or allows a suction device to be inserted if a hemothorax or collapsed lung is to be treated without invasive procedures. However, the cylindrical section and elongated duck bill valve are obtrusive. The dangling free end of the valve may be inadvertently caught and pulled by medical personnel or equipment so as to dislodge the chest seal and/or pressure from medical equipment or other dressings may prevent the duck bill valve from venting the chest wound. In fact the &#39;333 patent explains that the one-way valve may not open to allow air to be expelled if the patient is lying on the valve. 
     Thus, a need remains for a low profile chest seal that ensures effective venting of the pleural cavity while sealing a chest wound against air entry, without risk of being dislodged during treatment of the patient, particularly when invasive procedures or other auxiliary procedures are not required. 
     BRIEF DESCRIPTION OF THE INVENTION 
     The invention provides a chest seal for treating an open pneumothorax that is low profile and thus unobtrusive so that the chest seal can be effectively maintained in position to seal a chest wound while allowing the pleural cavity to vent. 
     Thus, the invention may be embodied in a chest seal comprising: a flexible flange body having a top side surface and a bottom side surface, said flange body having at least one opening defined therethrough in a central portion thereof; a biocompatible adhesive disposed on said bottom surface of said flexible flange body and at least one one-way valve secured with respect to said upper surface of said flange body so as to overlie a respective at least one said central opening, said one-way valve comprising a valve body having a peripheral wall, a passage defined therethrough, and a sealing element disposed in said valve body so as to selectively seat to seal said passage to preclude air flow in one direction through said valve body and so as to be selectively unseated to allow flow through said valve body in the opposite direction, whereby when the flange body is adhered to the skin of a patient with said at least one central opening generally overlying a chest wound, air is allowed to escape from the chest wound through the one-way valve whereas air flow into the chest wound is precluded. 
     The invention may also be embodied in a method of treating an open pneumothorax comprising: providing a chest seal comprising a flexible flange body having a top side surface and a bottom side surface, said flange body having at least one opening defined therethrough in a central portion thereof, a biocompatible adhesive disposed on said bottom surface of said flexible flange body, and a one-way valve secured with respect to said upper surface of said flange body so as to overlie a respective at least one said central opening, said one-way valve comprising a valve body having a peripheral wall, a passage defined therethrough and a sealing element disposed in said valve body so as to selectively seat to seal said passage to preclude air flow in one direction through said valve body and so as to be selectively unseated to allow flow through said valve body in the opposite direction; wiping the patient&#39;s skin in an area around the chest wound; applying the chest seal to the patient&#39;s skin with at least one said central opening overlying the chest wound; and pressing to adhere the adhesive to patient&#39;s skin around and about the chest wound, whereby air is allowed to escape from the chest wound through the one-way valve whereas air flow into the chest wound is precluded. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a chest seal embodying the invention with the backing material shown partly peeled away; 
         FIG. 2  is a top plan view of a chest seal according to an example embodiment of the invention; 
         FIG. 3  is a bottom plan view of the chest seal of  FIG. 1  with the peel-off backing removed; and 
         FIG. 4  is a cross-sectional view taken along lines  4 - 4  of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A chest seal  10  embodying the invention is comprised of a flange like main body  12  (hereinafter “flange body”) and at least one generally centrally disposed one-way valve  14 . The flange body  12  has a top side  16  and an under side  18  on which a biocompatible adhesive  20  is disposed for securing the flange body to a patient&#39;s skin. Suitable adhesives for adhering the flange body to the patient&#39;s skin include hydro gel, acrylic, silicone gel, silicone PSA or hydrocolloid. In the illustrated example embodiment, no adhesive is provided on a release tab projection  22  which is grasped to remove the chest seal flange body  12  from the patient&#39;s skin when the chest seal is to be removed. 
     Referring to  FIGS. 1 and 3 , a peel-off backing  24  is disposed to cover the adhesive  20  on the underside of the flange body  12 . The peel-off backing  24  also includes a finger pull  26 , which in the illustrated embodiment corresponds in location to the tab projection  22  of the flange body  12 . While typically the tab  22  will be of the same size and configuration as the finger pull  26  of the flange body, it is to be understood that these parts do not have to correspond in size and shape. 
     The flange body  12  is constructed of a pliable, flexible material so that the chest seal  10  can be applied to adhere to any contour of the patient&#39;s body. In this regard, it is important for the chest seal to conform to the patient&#39;s outer chest wall to effectively seal about the chest wound to block air inflow. In an example embodiment the flange body  12  is formed from 10 mil urethane. Other suitable body materials may include other thicknesses or polyurethane, polyethylene, polypropylene, nylon, or polyolefin. These can be in film or foam. In the illustrated example embodiment, the chest seal is generally circular and has a diameter of about 5 to 6 inches, although the shape of the flange body is not critical and a square flange body or flange body of other shape may be provided without departing from the invention. 
     As noted above, at least one one-way valve  14  is operatively coupled to the flange body  12 . In the illustrated example embodiment, at least one opening  28  is defined through the flange body  12  in general alignment with each one-way valve  14  so that when the flange body is adhered to the patient&#39;s outer chest wall, the one-way valve is in flow communication with the patient&#39;s chest wound through the opening(s)  28 . In this way air is allowed to escape from the chest wound through the one-way valve, but the one-way valve closes so as to block air in flow into the chest cavity. In the illustrated example embodiment, three one-way valves  14  are symmetrically disposed centrally of the flange body  12 , each aligned with a respective opening  28  through the flange body, to ensure effective venting of the wound even if the flange body is not precisely placed. 
     In the illustrated example embodiment, the one-way valve(s)  14  are secured or mounted to the flange body  12  by disposing a sealing membrane  30  to overlie the valve(s)  14  and adhere to the top side  16  of the flange body  12 . As illustrated in  FIGS. 1 and 2 , at least one opening  32  is defined through the mounting membrane in general alignment with each one-way valve  14  to complete the air circuit through the chest seal  10 . The valves may be attached using a pressure sensitive adhesive, RF welding and/or heat sealed to the flange body. Of course the number of openings  32  in the sealing membrane and size of the membrane will depend upon the number, size and placement of the one-way valves  14 . 
     Referring to  FIGS. 1 and 4 , in an example embodiment, the one-way valve is a Pacific Bag Inc. (PBi) one-way degassing valve, which is a very efficient single-part valve. In this regard, the mounting membrane  30  serves as a cap for the valve  14  and a sealing disk  34  for blocking air flow in one direction through the valve is held in place with three projections  36  that are incorporated directly into the valve body  38  instead of in a cap or other auxiliary component. As will be appreciated, the mounting membrane  30  and the integrally formed valve body  38  contribute to the generally low profile of the valve  14  consistent with the objects of the invention. In an example embodiment, the valve body  38  is molded plastic, such as polyethylene, polypropylene or nylon. Stainless or aluminum could be used if it is attached via a pressure sensitive adhesive, as one could produce a low profile valve in this configuration made of a metal. The sealing disk  34  is formed from an elastomeric material, such as natural rubber, that can be pushed past the projections  36  during assembly and can resiliently seal against the valve body  38  to block air flow through passage(s)  40  into the chest cavity. In the embodiment illustrated in  FIG. 4 , the sealing disk seats on the bottom wall of the valve body  38  which thus serves as the valve seat of the valve body. Moreover, in the illustrated embodiment, the valve body is configured and disposed such that its bottom wall is generally parallel to the plane of the flange body  12 . Although the provision of a sealing component in the form of a sealing disk  34  is presently preferred, it is to be appreciated that sealing components having other configurations, such as a ball or flap may be disposed in the valve body  38  as an alternative. In the illustrated example, furthermore, a filter membrane  42  is seated between the valve body and the flange body. The filter membrane, also referred to as a scrim, is provided to keep clots or debris from entering the one-way valve. In an example embodiment a polyester filter is provided, but other materials, such as nylon, polyethylene, polypropylene and fiberglass could be used. 
     As mentioned above, the single part design of the PBi valve makes it particularly low profile, which allows it to be readily incorporated in the chest seal of the invention, individually or, as in the illustrated embodiment, with two or more valves together defining a valving system. 
     To use the chest seal  10  of the invention in a non-invasive procedure, the patient&#39;s skin around the wound hole is wiped clean of blood and sweat to ensure appropriate adhesion of the chest seal  10 . The peel off backing  24  is removed by grasping the finger pull  26  and peeling away the backing to expose the adhesive  20  disposed on the under side  18  of the flange body  12 . The chest seal is then positioned over the wound hole so that the one-way valve(s)  14  generally overlie the wound hole. The flange body  12  is then pressed against the patient&#39;s skin to ensure that the chest seal has adhered completely to the patient&#39;s skin, so that air released from the wound will exit via the one-way valve(s)  14  whereas air inflow will be blocked by the adhesive attachment on the one hand and by the one-way valve(s) on the other hand. 
     While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.