Abstract:
The withdrawal spike comprises a piercing thorn ( 10 ) and a housing ( 12 ) having filter chambers for air and fluid. In a connecting piece ( 23 ) for connection of an external device a self-closing valve ( 31 ) is arranged. Said valve ( 31 ) is adapted to prevent fluid from unintentionally flowing out of the withdrawal spike.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a withdrawal spike for withdrawing medical liquids from containers. 
     A withdrawal spike, as is e. g. described in the patent DE 38 20 204 C2, comprises a piercing thorn having a ventilation duct and a fluid duct. The piercing thorn is connected with a gripping portion on which a connecting piece connected with the fluid duct is arranged. When the withdrawal spike is used, the piercing thorn penetrates through the elastomeric stopper of a bottle or any other container. Then a syringe or a hose line is connected to said connecting piece. The fluid container can be suspended upside down such that, during the withdrawal process, fluid may flow out of and air may enter the container. The withdrawal spike is further suitable for supplying fluid to the container. 
     The company B. Braun Melsungen AG, Germany, sells a withdrawal spike under the tradename Mini-Spike Plus. The connecting piece of said withdrawal spike is surrounded by a protective jacket which comprises a hinged cover. The closable protective jacket serves, on the one hand, as protection against contamination of the connecting piece, and prevents, on the other hand, uncontrolled leakage of fluid into the surroundings. 
     When heparin is withdrawn, all heparin syringes of the entire hospital ward are normally drawn up at a time. The piercing thorn is inserted into a heparin bottle and the latter is placed upside down for withdrawal purposes. The syringes placed in readiness, which have been taken out of their sterile packing, are successively connected to the connecting piece of the withdrawal spike and placed into the respective syringe packing after the withdrawal. During exchange of the syringes to be connected to the connecting piece of the withdrawal spike, the person drawing up the syringes continues to hold the bottle in the hand in an upside down manner. If the syringes are not exchanged very rapidly, heparin may drip from the open connecting piece and contaminate the surroundings. 
     In the case of cytostatic agents, which are toxic, the personnel always fears that the already opened bottles may fall over and become leaky. Therefore such bottles are frequently seal-welded into a PE-bag. The hinged cover of the Mini-Spike Plus spike is generally considered tight and safe. 
     In some countries it is common practice to use withdrawal spikes in conjunction with bags, i. e. a perfusor syringe is filled with the contents of a bag. This involves the danger of dripping. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a withdrawal spike offering a maximum of tightness and application reliability and a high degree of cleanliness, hygiene and comfort. 
     According to the present invention the connecting piece comprises a self-closing valve which is opened by insertion of a tube into the connecting piece. This reliably prevents dripping. In the valve according to the present invention the function of the protective jacket is essentially limited to the prevention of a contact contamination of the connecting piece. Protection against the leakage of fluid is offered by the valve which is in the open position only when a tubular object is pressed into the connecting piece. 
     Valves, which are opened by insertion of a tubular object, are known in the medical field, mainly for use in conjunction with hose connections, such as catheter connections. 
     According to the present invention a self-closing valve is integrated in the connecting piece of a withdrawal spike. This causes only a negligible additional expenditure which however offers considerable advantages with regard to application. For example, the exchange of syringes while drawing up heparin syringes is substantially facilitated. In the case of cytostatic agents the danger of the personnel coming in contact with toxic fluids is minimized. Further, the present invention offers advantages with respect to withdrawal of fluids from bags during which process the danger of uncontrolled leakage of fluid is particularly large. The fluid seal does not become effective only at the outlet of the connecting piece but already at its inlet such that the inner wall of the connecting piece is also protected against contamination. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Hereunder an embodiment of the present invention is described in detail with reference to the drawings in which: 
     FIG. 1 a part-sectional side view of the withdrawal spike, and 
     FIG. 2 a part-sectional perspective view of the connecting piece and the surrounding protective jacket. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The shown withdrawal spike comprises a piercing thorn  10  having at its one end a tip  11  for piercing the stopper of a bottle or any other container, and being on its other end integrally formed with a housing  12 . Said housing  12  is of plate-shaped configuration and acts as a carrier plate from which the piercing thorn  10  centrally protrudes. The housing  12  comprises a first filter chamber  13  containing a fluid filter and a second filter chamber  14  containing an air filter. Said air filter has a mesh width of 0.45 μm, and said fluid filter is a particle filter with a mesh width of 5 μm. 
     The piercing thorn  10  is provided with a removable protective cap  40 . 
     A fluid duct  15  and an air duct  16  extend in longitudinal direction through the piercing thorn  10 . Said two ducts  15 ,  16  end in the conical area of the tip  11  of the piercing thorn  10 . Inside the housing  12  the ducts  15 ,  16  are isolated from each other. The fluid duct  15  communicates with the filter chamber  13 , and the air duct  16  communicates with the filter chamber  14 . The filter chamber  13  is further connected with a duct  17  which extends through a tube  18  which, in extension of the piercing thorn  10 , is connected with the housing  12  and protrudes to the opposite side of the housing  12 . Two wing-shaped portions  19 ,  20  laterally engage with the tube  18 , said wing-shaped portions  19 ,  20  being configured as quadrantal sectors and extending between the tube  18  and the housing  12 . The two wing-shaped portions  19 ,  20  together form a semicircle located in a plane extending at right angles to the plane of the plate-shaped housing  12 . On both sides of the wing-shaped portions  19 ,  20  concentric ribs  21  are provided which facilitate the gripping by hand. Thus the wing-shaped portions  19 ,  20  form a gripping part, and the plate-shaped housing  12  forms a manually actuated impact surface when the piercing thorn  10  is inserted into a stopper. 
     In the wing-shaped portion  19  a vent hole  22  communicating with the filter chamber  14  is provided. In the air flow path the air filter membrane contained in the filter chamber  14  is arranged between the air duct  16  and the vent hole  22 . 
     At the end of the tube  18  a connecting piece  23  having an inner cone  24  and externally threaded ribs  25  of a Luer-Lock connector is arranged. Said connecting piece  23  is annularly surrounded, at a lateral distance, by a protective jacket  26 . Said protective jacket  26  comprises a bottom portion  27  sealingly adjoining the base part of the connecting piece  23 . The protective jacket  26  protrudes beyond the outer end of the connecting piece  23 . At the edge of the pot-shaped protective jacket  26  a hinged cover  27  is fastened by a living hinge  28 . Said cover  27  is further connected via a toggle joint arm  29  with the protective jacket  26 . Said toggle joint arm  29  effects a snapping behaviour of the cover  27  which assumes either the open position shown in FIG. 1 or the closed position. On the inside of the cover a projecting edge  39  is arranged which, in the closed position of the cover  27 , fittingly engages with the protective jacket  26 . Further, a cylindrical closing part  30  is provided on the inside of the cover  27 , said closing part  30  entering the inner cone  24  of the connecting piece  23 . 
     Inside the connecting piece  23  the valve  31  is arranged. Said valve  31  comprises a valve disk  32  and a valve opener  33 . The edge of said valve disk  32  of elastomeric material is clamped between the edge of the tube  18  and an edge of the connecting piece  23  and is gripped over by a sleeve  34  of the connecting piece  23 . The valve disk  32  comprises a slot or opening structure. It is of the self-closing type, i. e. without exertion of external pressure it assumes the closed position shown in the drawings. 
     The valve opener  33  is a tubular part containing a longitudinal duct  35  and a truncated cone  36  at its end, said truncated cone  36  pushing against the central portion of the valve disk  32 . On the circumferential area of the valve opener  33  projections  37  protruding to the outside are arranged which are distributed over the circumference. The upper ends of said projections  37  push against an annular shoulder  38  inside the connecting piece  23 . Above the annular shoulder  38  the inner cone  24  is located. 
     Below the valve disk  32  a cavity  41 , which is enlarged relative to the duct  17 , is provided, and the valve disk  32  can move into said cavity  41  when it is deformed by the valve opener  33 . 
     During use of the withdrawal spike a male Luer cone is placed upon the connecting piece  23 , or the cone of a syringe is inserted into the inner cone  24 . During this process the penetrating part pushes against the front face of the valve opener  33  whereby the latter is displaced inside the connecting piece  23  thus pressing the valve disk  32  open. The valve  31  is thus forced to remain in the open position as long as the external part protrudes into the connecting piece  23 . Thereafter the spring action of the valve disk  32  causes valve opener to return  33  into its initial position, and the valve  31  closes again. 
     Any fluid residues in the connecting piece  23  or in the valve  31  are prevented from flowing out by closing the cover  27 . 
     Although a preferred embodiment of the invention has been specifically illustrated and described herein, it is to be understood that minor variations may be made without departing from the spirit and scope of the invention, as defined in the appended claims.