Abstract:
The invention relates to a catheter insertion device comprising: an approximately hollow cylindrical catheter sleeve ( 2 ), at whose distal end a catheter ( 4 ) is attached; a needle sleeve ( 8 ) with a hollow needle ( 9 ), which is attached thereto and which, when ready for use, extends through the catheter sleeve ( 2 ) and the catheter ( 4 ), and; a needle protective element ( 13 ) that is arranged inside the catheter sleeve ( 2 ) while being able to move on the needle ( 9 ). Said needle protective element has an engaging section ( 13   c ) that engages with an engaging device ( 9   b ), which is formed in the vicinity of the needle tip, when the hollow needle is withdrawn from the catheter sleeve ( 2 ). A check valve ( 7, 17 ) is placed inside the catheter sleeve ( 2 ) between the catheter ( 4 ) and the needle protective element ( 13 ). The hollow needle ( 9 ), when ready for use, extends through said check valve, and the check valve automatically closes once the needle is withdrawn.

Description:
The invention relates to a catheter insertion device according to the preamble of claim  1 . 
   CROSS-REFERENCE TO RELATED APPLICATION 
   This is a U.S. national phase application of PCT application No. PCTJEP2003/007073, filed Jul. 2, 2003, which claims priority to German application Ser. No. 202 10 394.3, filed Jul. 4, 2002, the contents of these applications are expressly incorporated herein by reference. 
   BACKGROUND 
   A device of this kind is known from EP 352 928, wherein in a hollow catheter hub a needle guard element is arranged. On withdrawal of the hollow needle from the catheter over an engaging means near the tip of the hollow needle, the needle guard element engages with the engaging means and covers the tip when the hollow needle is separated from the catheter. In this design, after withdrawal of the hollow needle from the catheter, through this catheter blood can issue with which the operating personnel can come into contact. 
   The invention is based on the object of designing a catheter insertion device of the type described above such that an outflow of blood from the catheter is prevented after removal of the hollow needle with the needle guard element. 
   SUMMARY 
   This object is solved according to the invention by the features in the characterizing part of claim  1 . In the ready position, a check valve is arranged in the catheter hub between the catheter and the needle guard element. Through this valve the hollow needle extends, so that after withdrawal of the hollow needle from the catheter the latter can be reliably closed such that an outflow of blood is prevented, while simultaneously the tip of the hollow needle is securely covered by the needle guard element so that the operating personnel cannot injure themselves on the needle tip. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Exemplary embodiments of the invention are explained in more detail below with reference to the drawing, in which: 
       FIG. 1  shows a longitudinal section through a catheter insertion device in the ready position, 
       FIG. 2  shows the catheter insertion device with the hollow needle removed, 
       FIG. 3  shows the device with an attached syringe, 
       FIG. 4  shows a sectional view along the line A-A in  FIG. 1 , 
       FIG. 5  shows a longitudinal section through another embodiment, 
       FIG. 6  shows a view of the valve disc, 
       FIG. 7  shows different views of a valve actuating element, 
       FIG. 8  shows a longitudinal section through a further embodiment, 
       FIG. 9  shows front views of the valve actuating element of  FIG. 8 , and 
       FIG. 10  shows a longitudinal section through a further embodiment. 
   

   DETAILED DESCRIPTION 
     FIG. 1  shows a catheter insertion device  1  having a catheter hub  2  which has a two-part form in the embodiment. A distal hub element  3  of the catheter hub has a holding section  3   a  in which a catheter  4  is press-fitted. The proximal end of the hub element  3  has an enlarged diameter with regard to the distal end and forms a connecting section with a hub element  5  whose distal end overlaps the proximal end of the hub element  3  and which is provided at its proximal end with a Luer thread  6 . Between the two hub elements  3  and  5 , a check valve in the form of a valve disc  7  is inserted and is fixed in place by the two hub elements  3  and  5 . 
   In the ready position according to  FIG. 1 , there is inserted in the catheter hub  2  a needle hub  8  to which a hollow needle  9  is fixed which extends through the valve disc  7  and the catheter  4  so that the needle tip  9   a  is exposed. Between needle hub  8  and valve disc  7  there is displaceably arranged in the proximal hub element  5  a valve actuating element  10  which has a truncated cone-shaped locating section  10   a  which serves to open the valve disc  7 , as  FIG. 3  shows. On the proximal side, a plunger section  10   b  adjoins the locating section  10   a  and has a hollow space for receiving a needle guard element  13 . In the embodiment shown, the plunger section  10   b  is formed by two spaced plungers between which the needle guard element in the form of a spring clip  13  is inserted, as shown in the cross-sectional view in  FIG. 4 . 
   On withdrawal of the hollow needle  9  from the catheter hub  2 , an engaging means  9   b  ( FIG. 2 ), provided near the needle tip  9   a  and having the form of a radial projection on the hollow needle which can be formed by light crimping, engages with the outer circumference of a bore in the rear wall  13   c  of the spring clip  13 , so that the spring clip  13  is removed from the catheter hub with the needle  9 , while simultaneously the spring arms  13   a  and  13   b  of the spring clip cover the needle tip, completely protecting and blocking it. In this separated position shown in  FIG. 2 , the valve disc  7 , due to its elasticity, closes the through-hole for the hollow needle  9  so that no blood can flow out through the catheter  4 . As  FIG. 6  shows, the valve disc is provided for example with three slits  7   a  starting from the middle and extending radially over a short section X, forming elastic flaps  7   b  therebetween which can be expanded by the hollow needle. 
     FIG. 3  shows the insertion of a syringe  14  in the catheter hub  2 , wherein the neck portion  14   a  of the syringe comes to abut on the plunger section  10   b  of the valve actuating element  10  and presses it against the valve disc  7 , so that the truncated cone-shaped locating section  10   a  outwardly displaces the flaps  7   b  of the valve disc and thereby opens the valve, so that a liquid can be inserted from the syringe  14  into the catheter  4 . 
   The incline of the truncated cone on the locating section  10   a  and the displacement path of the actuating element  10  relative to the valve disc  7  are designed such that due to the elasticity of the material of the valve disc  7 , the flaps  7   b  displace the locating section  10   a  to the right in  FIG. 3  when the syringe  14  is removed from the catheter hub  2 . Hereby, the valve disc  7  is automatically closed, as the position in  FIG. 2  shows. 
   In the hub element  5 , there is formed by a shoulder  5   a  a stop for the actuating element  10 , to define the position of the actuating element in the separated position in  FIG. 2 . Hereby, the truncated cone-shaped locating section  10   a  lies near the stop  5   a , while its distal end abuts on the valve disc  7  as shown in  FIG. 2 . The radial slits  7   a  of the valve disc  7  are designed such that in the ready position in  FIG. 1 , the flaps  7   b  are bent radially upwards less than in the open position by the locating section  10   a  in  FIG. 3 . 
   As the cross-sectional view in  FIG. 4  shows, the two plungers lob of the valve actuating element  10  are guided in longitudinal grooves  5   e  of the hub element  5  and they project radially inwards into the bore  5   c  of the hub element  5 , so that they form an abutting surface for the neck portion  14   a  of the syringe  14 . The bore  5   c  in the hub element  5  is formed slightly conically corresponding to the conical neck portion  14   a  of a syringe. 
   On the inner circumference of the bore  5   c  of the hub element  5 , a further shoulder  5   b  having a smaller diameter is formed, on which the radially outer areas of the spring arms  13   a  and  13   b  abut in the ready position in  FIG. 1 . Hereby, the spring clip  13  is fixed in its position in the hub element  5 . When the needle hub  8  with the hollow needle  9  is removed from the catheter hub  2 , first the spring clip  13  is held on the shoulder  5   b  by abutting until the radial projection  9   b  comes to abut on the rear wall  13   c  of the spring clip. In this position, the two spring arms  13   a ,  13   b  can be released from the shoulder  5   b  and spring back inwards to cover the needle tip, as  FIG. 2  shows, whereupon the spring clip  13  with the hollow needle  9  can be removed from the catheter hub. 
   In the embodiment according to  FIGS. 1 to 3 , the distal end section of the hub element  5  is shrunk, welded or bonded onto the proximal end section of the hub element  3  after the valve actuating element  10  and the valve disc  7  are inserted in the hub element  5 . It is also possible to join the two hub elements  3  and  5  to one another, for example by a thread which is secured against loosening after assembly. The spring clip  13  is inserted together with the hollow needle  9  in the bore  5   c  of the hub element  5  during assembly, wherein the radially outer areas of the spring arms  13   a ,  13   b  snap in at the shoulder  5   b  under elastic deformation. 
   Preferably, in front of the shoulder  5   b  a projection  5   b ′ can be formed in the bore  5   c  of the hub element, as shown in  FIG. 2 . Hereby the snap-in and holding effect of the spring clip  13  is increased. 
     FIG. 5  shows a modified embodiment of the connection of the two hub elements  3  and  5 , in which two cylindrical sections  3   b  and  5   d  engage in one another. A thread can be provided between these two cylindrical sections. However, it is also possible to bond or weld these two sections. 
   In this embodiment, the valve actuating element  10  is also modified in relation to the embodiment of  FIGS. 1 to 3 .  FIG. 7   a  shows a side view of the approximately U-shaped actuating element  10  with the spring clip  13  inserted therein. As the side view rotated by 90° in  FIG. 7   b  shows, the locating section  10   a  is partly flattened on opposite sides so that the width of the plunger sections  10   b  extends into the locating section  10   a .  FIG. 7   c  is a front view from the left in  FIG. 7   b  and shows the flattened structure of the locating section  10   a .  FIG. 7   d  is a sectional view along the central line in  FIG. 7   b .  FIG. 7   e  shows a section through the valve actuating element  10  along the line B-B in  FIG. 7   d.    
     FIG. 5  shows the lower half of the valve actuating element  10  corresponding to the view in  FIG. 7   a , and the upper half in a sectional view rotated by 90° corresponding to  FIG. 7   b . The shoulder  5   a  for positioning the valve actuating element  10  in the hub element  5  is hereby formed on the ends of the diametrically opposite grooves  5   e  ( FIG. 4 ), so that the proximal ends of the plunger sections  10   b  abut on the shoulders  5   a . Corresponding to the shoulder  5   b  in  FIGS. 1 to 3  in the embodiment in  FIG. 5 , there is formed on the hub element  5  a projection  5   f  which projects inwards at diametrically opposite positions on the bore  5   c  of the hub element  5  and fixes the spring clip  13  in the hub element  5  until the spring arms  13   a ,  13   b  spring inwards over the needle tip and the spring clip with the hollow needle  9  is removed from the catheter hub. 
     FIG. 8  shows a modified embodiment having a hollow cylindrical valve actuating element  10  on whose inner circumference a projection  10   f  is formed for positioning the spring clip  13  inside the valve actuating element  10 .  FIG. 9   a  shows a front view of the valve actuating element  10  from the right and  FIG. 9   b  shows a front view from the left in  FIG. 8 , wherein for locating the neck portion  14   a  of a syringe  14 , in this embodiment radially inwardly projecting ribs  10   e  are formed which protrude radially into the bore  5   c  of the hub element  5 , as the upper half of the valve actuating element in  FIG. 8  shows, in which the sectional view of the lower half of the valve actuating element  10  is shown rotated by 90° in relation to the upper half. 
     FIG. 10  shows a modified embodiment wherein between the two hub elements  3  and  5  a check valve  17  is inserted, which has a hollow cylindrical section  17   b  starting from a flange section  17   a  and abutting on the inner circumference of the hub element  3 . From the inner circumference near the flange section  17   a  there start two opposite flaps  17   c , which abut on the outer circumference of the hollow needle  9  in the ready position in  FIG. 10 . When the needle  9  is removed from the catheter hub  2 , the elastically deformed flaps  17   c  move inwards and close the valve. In this embodiment, an actuating element for opening the valve  17  is not necessary, because the pressure of the fluid from the syringe  14  displaces the flaps  17   c  radially outwards so that the liquid can flow out through the valve  17 . In this embodiment of a check valve, a so-called duck-bill valve is concerned, whose construction is in itself known. 
   In  FIG. 10 , in order to allow the spring clip  13  to be held in the catheter hub during withdrawal of the hollow needle  9  from the catheter hub  2  until the radial projection  9   b  on the hollow needle engages with the rear wall  13   c  to cover the needle tip, in this embodiment there is formed on the inner circumference of the proximal hub element  5  a projection  5   f  which extends radially inwards and on which the radially outer areas of the spring arms  13   a  and  13   b  come to abut and hold the spring clip until the spring arms spring back radially inwards to cover the needle tip. The inner diameter of the projection  5   f  is designed only slightly smaller than the maximum radial dimension at the spring arms  13   a  and  13   b , so that during assembly the spring clip  13  can be inserted by slight pressure into the position in the catheter hub as shown in  FIG. 10 . 
   In the embodiment of a catheter insertion device according to  FIGS. 1 to 9 , in the position of the valve actuating element  10  in  FIG. 2  the valve disc  7  can be opened by low pressure produced by the syringe  4  for drawing off liquid from the catheter, wherein the elastic flaps  7   b  are bent upward by the low pressure. In the embodiment of  FIG. 10 , a drawing-off of liquid from the catheter is not possible, because the duck-bill valve does not open when there is low pressure on the proximal side. 
   It is convenient to fabricate the check valve in the form of a valve disc  7  or of the flap valve  17  from elastic silicon, while a correspondingly rigid plastic material is used for the hub elements  3  and  5  and for the valve actuating element  10 .