Abstract:
A tube connection adapter for coupling one or more tubes of a chest drainage system to a bottle. The adapter has a body adapted to fit onto the mouth of a bottle, the body having an inlet fitting adapted to be connected to a tube of the drainage system to permit entry of fluid into the bottle, and a pressure relief valve adapted to communicate with the interior of the bottle to permit release of pressure in the event of a pressure build-up occurring within the bottle. The pressure relief valve may include a simple ball valve or poppet valve and can be fitted into the adapter body even when there are two or more inlet/outlet fittings.

Description:
RELATED APPLICATIONS 
   This application claims the benefit of the Australian application PQ 3744 filed Oct. 29, 1999 and the international application PCT/AU00/01313 filed Oct. 26, 2000 designating the United States. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to chest drainage systems for draining gas and exudate from a patient following surgery. 
   2. Description of the Related Art 
   Chest drainage systems generally include at least one bottle connected to a patient to collect gas and exudate leaking into the thoracic cavity, by allowing drainage to a position lower than the patient while still allowing the patient to breathe. Depending on the needs of a particular patient, chest drainage systems can be set up to operate in different modes. In one mode, drainage can take place by gravity alone and, in other modes, drainage is assisted by the application of external suction by attaching a suction line to the system. A typical chest drainage system will include one, two, or three series—connected bottles depending on the particular set-up. Irrespective of the actual set-up used, one of the bottles will usually include a water seal associated with the inlet tube to that bottle to ensure that air or gas cannot return along the tube once it has bubbled out of the tube; thus the water seal acts as a one-way valve ensuring drainage away from the cavity without permitting air to return. Depending on the set-up used, the system may also have a separate collection bottle and a bottle for controlling the degree of suction. 
   However, a life-threatening situation can occur if the outlet to one or more of the bottles is closed, for example by being blocked or pinched off whereby the drainage action is restricted with the result that eventually the patient may no longer be able to breathe. This situation is known as pneumothorax. Blockage of an outlet can occur if an outlet tube or  suction tube becomes kinked or if a valve linking a suction tube to a suction system is closed without the line being disconnected from the valve. 
   SUMMARY OF THE INVENTION 
   According to the present invention, there is provided a tube connection adapter for coupling one or more tubes of a chest drainage system to a bottle, the adapter having a body adapted to fit onto the mouth of a bottle and an inlet fitting adapted to be connected to a tube of the drainage system to permit entry of fluid into the bottle, the body including a pressure relief valve adapted to communicate with the interior of the associated bottle to permit release of pressure in the event of a pressure build-up occurring within the bottle. 
   As a result of the release of positive pressure, drainage of exudate from the patient can still take place even if an outlet of the system is blocked, thereby reducing the risk of pneumothorax. 
   When the system is a two- or three-bottle system, the adapter is used with at least the first bottle of the system. 
   In one embodiment of the invention, a lower part of the adapter body is sized to fit within the mouth of an associated bottle and is bordered by a flange supported by the upper end edge of the mouth of the bottle, the inlet connection fitting of the adapter and the pressure relief valve being incorporated within a zone of the body axially aligned with the lower part thereof to ensure communication with the interior of the bottle. 
   In one embodiment, the body has at least one further tube connection fitting for example to coupling to an outlet tube and/or a manometer tube. Advantageously, the valve is a simple ball valve, poppet valve, or the like which is closed under the effects of negative pressure within the bottle and which automatically opens under the effects of positive pressure. 
   In practice, the adapter is secured in its operative position to the mouth of the bottle by a screw-threaded coupling ring rotatably mounted on the body of the adapter. 
   Further according to the invention there is provided a chest drainage system comprising one or more collection bottles, tubing associated with the bottles for  connection to the patient and an adapter as defined above associated with at least the first bottle of the system for coupling the tubing to the bottle. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: 
       FIG. 1  shows schematically a two-bottle chest drainage system without suction assistance; 
       FIG. 2  shows schematically a three-bottle system with suction assistance; 
       FIG. 3  is a perspective view showing schematically a tube connection adapter in accordance with one embodiment of the invention; 
       FIG. 4  is a schematic section through the adapter shown in  FIG. 3 ; 
       FIGS. 5A to 5D  are schematic sections showing different forms of pressure relief valve which can be incorporated within the adapter; and 
       FIGS. 6A to 6D  are underneath views of the adapter showing possible positions for the valve in different configurations of inlet and outlet connections. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1  illustrates a typical two-bottle system operating by gravity alone. In this system exudate from the patient drains into the first bottle  2  which is a collection bottle, the first bottle  2  being linked by a flexible tube  4  to a second bottle  6  which forms a water seal using a rigid inlet tube  8  connected to the tube  4  and having a lower end submerged beneath water filling the bottle to a predetermined level. An air vent  10  communicates the interior of the bottle  6  with atmosphere. 
   A single-bottle gravity system will utilize just the second of the two bottles shown in  FIG. 1 , with the inlet line  4  being connected directly to the patient. Although a single-bottle gravity system of this type does have the disadvantage that exudate draining into the bottle will progressively raise the level of the water seal within the bottle thereby progressively increasing the resistance of the drainage system, in practice there are  situations where this can be tolerated particularly when the rate of discharge of exudate is relatively low. 
     FIG. 2  shows a typical three-bottle system used in a situation where suction assistance is provided. In this system the first and second bottles  2 , 6  are equivalent to those of the gravity-only system just described except that the outlet from the second bottle  6  is connected by a flexible tube  12  to a third bottle  14  incorporating a manometer tube  16 , the outlet from the third bottle  14  being connected to a suction line. The third bottle  14  forms the function of a suction control, the degree of suction being determined by the level of water within that bottle via the manometer tube  16  which is open to atmosphere. A two-bottle system utilizing controlled suction will consist of just the second and third bottles  6 , 14  just described, with the exudate from the patient draining directly into the bottle  6  which forms the water seal. Although this will result in the level within the water seal bottle progressively rising, the effects of the suction assistance will offset this at least to a degree. The three-bottle system is generally to be preferred in certain applications as the use of the separate collection bottle  2  forming the first of the series of three bottles provides for maximum volume of drained exudate before replacement of the bottle is required and also ensures a constant suction action. Although the systems with suction assistance as described above include two or three bottles having the different functions described, it is also possible to provide a single-bottle system with suction assistance using the second of the two bottles shown. In practice a single-bottle system with suction-assistance does have significant utility in hospitals having a controlled wall suction system when the patient is not subject to excessive bleeding. 
   In each case the inlet and outlet to each bottle is formed by an adapter  20  (see  FIGS. 3 and 4 ) having an annular flange  22  which rests on the upper edge of the mouth of the bottle, with a lower part  20   a  of the adapter projecting into the mouth to locate the adapter. The adapter  20  is attached to the bottle by a threaded coupling ring  24  rotatably mounted on the body of the adapter  20  above the flange  22  and having an internally-threaded skirt projecting beneath the flange  22  to engage an external thread of the bottle. The adapter  20  is formed with tubular spigots  26  to which can be attached a flexible inlet tube, a flexible outlet or suction tube, the rigid inlet tube of the water seal or the manometer tube of a suction  control, the number of and configuration of the connecting spigots  26  being determined by the particular function the associated bottle is to perform within the drainage system. As will be appreciated, a range of different adapters with different numbers of connecting spigots will be provided to suit the various different set-ups just described. However in each case the inlet/outlet spigots will be configured to lie within a circular zone of a diameter no greater than the internal diameter of the bottle. Advantageously, the adapter  20  and threaded coupling ring  24  is sized to fit onto a bottle having a standardized mouth diameter so that any available bottle having that diameter of mouth can be used in the system. 
   In accordance with the invention, the adapter  20  for the bottle of a single-bottle system and at least the adapter  20  for the first bottle of a two or more bottle system (the bottle connected to the patient) also includes a simple pressure relief valve  30  to inhibit build-up of pressure within the associated bottle in the event of blockage occurring at the outlet to the bottle in circumstances such as those previously discussed. Accordingly drainage of exudate can still take place thereby reducing the risk of pneumothorax. In a system having two or more bottles the adapter for each bottle may incorporate the pressure relief valve  30 . 
   Suitable forms of pressure relief valve  30  are shown schematically in  FIGS. 5A to 5D .  FIG. 5A  shows a ball valve,  FIG. 5B  shows a poppet valve,  FIG. 5C  shows an umbrella-type valve, and  FIG. 5D  shows a duck bill-type valve. In each case the valve  30  is automatically responsive to positive pressure within the associated bottle to automatically open in order to release that pressure and this will ensure that drainage from the patient is not inhibited, while under normal operational conditions the valve will remain closed. For the valves of  FIGS. 5A to 5C , the valve member is of light weight and is gravity biased into its closed position in engagement with the valve seat and the effect of any negative pressure within the bottle will be to retain the valve member in the closed position; the valve member will move to an open position even under the effect of small positive pressure. For the valve of  FIG. 5D  the valve member is subject to an inherent resilient bias which deforms the valve member to a configuration which closes a passage through the valve, the valve member being deformed against the bias under the effect of positive pressure to open the passage. Although the available space in the adapter  20  is restricted, nevertheless  there is sufficient space to incorporate the valve  30  within the aforesaid circular zone even in an adapter  20  having three sets of connector spigots  26  as will be described below. 
   Possible positions P for the valve in relation to the inlet/outlet connector spigots are shown in  FIGS. 6A to 6D .  FIG. 6A  shows the valve position P in an adapter having an inlet spigot  26 , with the adapter having an outlet port arrangement such as for use in a single bottle gravity-only system.  FIG. 6B  shows the valve position P in an adapter having an inlet spigot  26  and a suction outlet  26   a .  FIG. 6C  shows an adapter with an inlet spigot  26 , a suction outlet  26   a  and a fitting for use with a manometer tube  26   b  and  FIG. 6D  shows an adapter with an inlet spigot  26 , and an outlet or second inlet spigot  26   c . The configuration of  FIG. 6A  is also suitable for use in a single-bottle system with suction assistance, with a suction port being molded into the bottle itself and the configuration of  FIG. 6D  is suitable for use in a single-bottle system having two patient inlet lines, connected to the spigots  26  and  26   c  with suction assistance provided by a suction port molded into the bottle itself. This range of configurations is suitable for use with the sole bottle of a single-bottle system either with or without suction assistance, or for use with the first bottle of a two- or three-bottle system either with or without suction assistance. 
   The adapter  20  is integrally molded in a suitable plastics material and the valve  30  may be incorporated into the adapter  20  by forming within the adapter a suitable socket  32  (see  FIG. 4 ) into which a valve structure consisting of the valve member and valve seat (if applicable) is located. 
   The adapters described above represent a range of adapters for use with the sole bottle of a single-bottle system either with or without suction assistance or for the first bottle of a two- or three-bottle system either with or without suction assistance. Although it is considered important for the pressure relief function to be applied to the first bottle of a two- or three-bottle system, depending on requirements pressure relief can also be applied to the or each other bottle of the system and the range of adapters described above can also fulfil this function. The pressure relief function provided by each adapter is unaffected by the type of bottle to which the adapter is attached. 
   The embodiments have been described by way of example only and modifications are possible within the scope of the invention.  
   Throughout this specification and claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or group of integers or steps but not the exclusion of any other integer or group of integers.