Abstract:
An insertion aid for inserting a cannula of a catheter head into organic tissue, in particular a catheter head for administering a liquid active substance, wherein the insertion aid includes a guide needle that is fixed to a grip section for removably inserting and stabilising the cannula during insertion into the organic tissue and a needle shield, having at least two sections, which is secured in a pivotable manner to the grip section and which encases and shields the guide needle when the insertion aid is separated from the catheter head.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S)  
       [0001]     This application is a continuation of International Patent Application No. PCT/EP2003/011730, filed on Oct. 23, 2003, which claims priority to German Application No. 102 54 443.3, filed on Nov. 21, 2002, the contents of which are incorporated herein by reference in their entirety. 
     
    
     BACKGROUND  
       [0002]     The present invention relates to devices and methods for using cannulae and the like and, more particularly, to an insertion aid for inserting a cannula of a catheter head into organic tissue, in particular a catheter head for administering a liquid active substance.  
         [0003]     Such catheter heads are used in conjunction with infusion devices, for example, so that a patient to whom a fluid is to be administered continuously or repeatedly does not need to have his or her skin repeatedly punctured. Part of the catheter head remains on the patient, namely a cannula housing together with the cannula protruding from it. Another part of the catheter head, having a connection element with a fluid conduit, can be detached from and reconnected to the cannula housing. By means of the connection element, an injection device or an infusion device can be repeatedly attached to the cannula housing and removed from it again, for example in order to exchange a container of fluid or to perform other maneuvers on the injection device or the infusion device. Such a catheter head can also be used, for example, to withdraw analysis fluid from a patient&#39;s body or to pass the analysis fluid into and back out of the body. The catheter head usually has a soft cannula which extends into the tissue and which in most cases cannot be introduced into the body without a stabilizing insertion aid. In particular, a soft cannula has to be guided and stabilized in order to puncture the outer layers of skin.  
         [0004]     To guide and stabilize the soft cannula of the catheter head, an insertion aid is known which has a guide needle to be pushed into the soft cannula and which can be removed and disposed of after the catheter head is anchored in or on the body or the organic tissue. To exclude any risk of injury to the person handling the insertion aid when removing and disposing of it, it is expedient to provide the guide needle with a needle guard which can largely prevent direct contact and risk of injury. A device for inserting a catheter head with the aid of a stiffening guide needle is known from WO 00/03757. This device has a guide needle which is anchored on a grip section and which, after removal from the catheter head, can be covered with the aid of a protective device. For this purpose, a shield with a contour in the shape of a segment of a cylinder is folded partially about the needle and is locked in position with the aid of interlocking hooks. The guide needle is thus provided with a protective and shielding enclosure, with the result that the device can be disposed of easily and without danger.  
       SUMMARY  
       [0005]     An object of the present invention is to make available an insertion aid for inserting a cannula of a catheter head into organic tissue, which permits safe handling of a needle guard and can reliably prevent contact with the guide needle after removal from the catheter head.  
         [0006]     According to the invention, an insertion aid of the type described at the outset is provided with a needle guard, comprising at least two parts, which is anchored in a pivotable manner on a grip section and which encloses and shields the guide needle when the insertion aid is separated from the catheter head. In some embodiments, the two parts of the needle guard are preferably pivotable with respect to the grip section, whereby they are moveable toward each other and can be locked together. The insertion aid is needed to assist in puncturing the skin when using infusion sets with a soft cannula. After use, the insertion or puncture aid is separated from the infusion set and can be disposed of. To ensure that the user or a third party cannot be injured by the needle, the latter is covered immediately after removal from the infusion set. The present invention affords a simple and safe way of guaranteeing this protection. In particular, the pivotable parts of the needle guard mean that recapping is unnecessary. The movement of the fingers during use of the needle guard is advantageously not directed toward the needle tip, but instead laterally with respect to the latter and obliquely away from it. The interlocking of the two parts of the needle guard ensures that, during or after its disposal, the needle cannot be inadvertently exposed and thus cause accidental contact. The interlocking can be cancelled out preferably only by applying a certain tensile force, for example if the insertion aid is to be recycled.  
         [0007]     In one embodiment, the present invention comprises an insertion aid comprising a needle guard comprising a grip section and at least two parts moveably coupled to the grip section, said two parts being moveable relative to the grip section to substantially enclose a guide needle after a use of the guide needle.  
         [0008]     In a preferred illustrative embodiment, the two parts of the needle guard are anchored, connected or coupled in a pivotable and/or foldable manner on the grip section via, in each case, at least one film or living hinge. The hinges preferably have an easy locking action in one position in which the parts of the insertion aid designed as flat shields are generally co-planar and perpendicular to the shaft and tip of the needle. This defined locking position can be overcome by turning or moving the shields inwardly, ie., moving their respective free edges towrd each other, with application of minimal force so that, after the locking position has been overcome, the two parts can easily move toward one another, after which the two parts of the needle guard can be interlocked in their end position in which they are generally parallel.  
         [0009]     In some embodiments, the two parts of the needle guard are preferably each designed as disk-shaped shields. In a further embodiment of the invention, the shields each have arc-shaped web sections which, when they are locked together, slide one inside the other and form a labyrinthine enclosure and shielding for the guide needle. The web sections slide in one another in such a way that a substantially tight and, at the same time, stabilizing connection of the shields is possible.  
         [0010]     In some embodiments, a centering web spaced apart from the guide needle is preferably arranged on a lower end face of the grip section, the centering web being able to ensure correct centering and positioning of the insertion aid on the catheter head. The shields of the needle guard are configured in such a way that this centering web is not in the way when the shields are folded closed and locked together. This can be made possible by suitably configuring the hinges in two parts.  
         [0011]     In some embodiments, the grip section preferably has a cylindrical contour with grip surfaces lying opposite one another on its outer circumferential surface. In this way, the insertion aid can be easily and safely handled so that, when the two parts of the needle guard engage one inside the other, the grip section is at the same time held secure. The grip section and the needle guard are preferably in one piece and can be made, for example, of plastic which can be processed in, for example, an injection molding process. In this way, the hinges can be produced, and the guide needles can be secured in the grip section, in one operation.  
         [0012]     When the parts of the needle guard are locked together, the guide needle is substantially enclosed by these parts, in some preferred embodiments without touching them, and it is in this way safely protected from touching during disposal of the insertion aid. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]      FIG. 1  is a schematic perspective view of an insertion aid, according to the present invention, fitted on a catheter head,  
         [0014]      FIG. 2  is a schematic perspective view of the insertion aid according to  FIG. 1  released from the catheter head,  
         [0015]      FIG. 3  shows the insertion aid according to  FIG. 2  in an oblique view from underneath,  
         [0016]      FIG. 4  is a bottom view of the insertion aid according to  FIGS. 1 through 3 ,  
         [0017]      FIG. 5  is a longitudinal section through the insertion aid according to the invention along section line V-V in  FIG. 4 ,  
         [0018]      FIG. 6  shows the insertion aid according to the present invention with the parts of a needle guard locked together, and  
         [0019]      FIG. 7  is a side view of the insertion aid with the parts of the needle guard locked together as in  FIG. 6 . 
     
    
     DETAILED DESCRIPTION  
       [0020]      FIGS. 1 through 3  depict an insertion aid  2  according to the present invention in a perspective schematic view. The insertion aid  2  comprises a cylindrical grip section  4  and, anchored on this, a guide needle  6  for stabilizing and guiding a soft cannula  8  of a catheter head of which, in the view shown in  FIG. 1 , only a plaster  10  and a guide section  42  can be seen. When the catheter head is in the applied position, the plaster  10  lies on the skin of the organic tissue. The cannula  8  is intended to puncture the skin and permit delivery and/or removal of fluid into and out of the organic tissue. After removal of the insertion aid  2 , an infusion set or the like can be placed on the guide section  42  and anchored there.  
         [0021]     The guide needle  6  has an external diameter which substantially corresponds to an internal diameter of the soft cannula  8 . By means of the stiffening and stabilizing of the cannula  8  and a beveled tip of the guide needle  6 , this can easily penetrate the tissue and be applied at the intended infusion site.  
         [0022]     The grip section  4  has a cylindrical outer circumferential surface  26  with two grip surfaces  28  lying opposite one another and intended for gripping with two fingers. On the lower end face of the grip section  4  from which the guide needle  6  also protrudes, first and second shields  16 ,  18  are secured in a pivotable manner via film or living hinges  14 . Other suitable hinge forms or connectors which enable a relative folding movement may be used. When the insertion aid  2  is removed, the shields can be pivoted over the guide needle  6  and can shield the latter from contact from outside. The first and second shields  16 ,  18  each have a disk-shaped contour, with a tab  38  formed on the second shield  18 . The tab  38  indicates to the user, among other things, in which orientation the connection element is connected to the cannula housing of the catheter head. When the two shields  16 ,  18  are joined and locked together, the tab  38  points vertically downward (cf.  FIGS. 6 and 7 ).  
         [0023]     In a plan view, the shields  16  and  18  each have an approximately mushroom-shaped silhouette, with a narrower section  44  being anchored at one end on the grip section  4  via the hinges  14 . At its opposite end, the narrower section  44  is adjoined by a roof-like wider section  46  which has a straight main face pointing toward the narrow section  44 , and, lying away from this, a curved face. At the sides, the straight main face merges into the curved face via a radius of curvature. The curved faces of the wide section  46  each point downward when the two parts are locked together. The grip tab  38  points vertically downward (cf.  FIGS. 6 and 7 ) from the curved face of the second shield  18 . The narrow sections  44  have a width which approximately corresponds to the diameter of the outer circumferential surface  26  of the grip section  4 . The wide sections  46  are approximately double or slightly less than double the width of the narrow sections  44 .  
         [0024]     On the undersides of the first and second shields  16 ,  18  facing away from the grip section  4  when the needle guard  12  is in the folded-out state, there are in each case web sections  20 ,  22  which follow the arc of the outer edge contours of the wide sections  46  of the shields  16 ,  18  and which, through engagement and interlocking of the two shields, permit a labyrinthine enclosure. The first web section  20  has a slightly larger contour engaging round the second web section  22 , with the result that the second web section  22  is completely enclosed by the first web section  20  when the shields are engaged in one another (cf.  FIGS. 6 and 7 ). The second web section  22  of the second shield  18  does not, however, follow the contour of the grip tab  38 , but instead only the contours of the wide section  46 . On the sides of the narrower section  44  facing toward the grip section  4 , the web sections  20 ,  22  are in each case open, so that they do not collide with the guide needle  6 . The web sections  20 ,  22  thus do not follow the narrow section  44 , but instead end at this. Thus, the web sections  20 ,  22  in each case as a whole have a mushroom-like profile which follows an area of the outer contour of the shields  16 ,  18 . The contour and profile of the web sections  20 ,  22  can be seen in  FIGS. 3 and 4 .  
         [0025]     Provided around the guide needle  6 , and spaced apart from it, there is a centering web  24  which comprises two webs in the shape of generally semicircular segments and which is used to ensure correct and accurate placement of the insertion aid  2  on the catheter head (not shown). This centering web  24  is likewise illustrated in  FIGS. 3 and 4 .  
         [0026]     To ensure that the shields  16 ,  18  do not collide with the centering web  24  when folded together, their film hinges  14  are in two parts and are arranged on both sides of the centering web  24 , i.e., at the edges of the lower end face of the grip section  4 . The two short film hinges of each of the two shields  16 ,  18  are continued in each case by a narrow connecting section. The two connecting sections of each shield  16 ,  18  thus form the narrow sections  44  thereof and each open into the wider section  46 .  
         [0027]     The shields have corresponding catch connections, a recess on the first shield  16  being provided with catches  32  arranged on the first web section  20 . On the second shield  18 , at its second web section  22 , there are corresponding undercuts  36  into which the catches  32  each engage and thus ensure locking of the two parts. The two undercuts  36  in the second web section  22  of the second shield  18  adjoin two recesses  34  in the flat upper face of the shield. The catches  32  adjoin a first recess  30  on the upper face of the first shield  16 .  
         [0028]     As is illustrated in  FIG. 5 , the guide needle  6  is secured with its upper section in an anchor  40  in the grip section  4 . In a preferred embodiment, the grip section  4 , and the shields  16 ,  18  anchored thereon via the hinges  14 , can be made of plastic in an injection molding process. The guide needle  6  can in this way be easily secured in the grip section  4  or in its anchor  40  during the injection molding process. The hinges  14  too can be produced by an injection molding process, with the result that they can be produced along with the other components in a joint operation.  
         [0029]     The two shields  16 ,  18  can be moved toward one another and pivoted relative to one another, via the hinges  14  at the lower end face of the grip section  4 , until the catches  32  lock in the undercuts  36 . The second web section  22  is at the same time substantially completely enclosed by the first web section  20  (cf.  FIG. 6 ). As is illustrated in  FIG. 7 , the guide needle  6  in this case is suitably completely shielded and enclosed by the two shields  16 ,  18  and by the web sections  20 ,  22  engaged in one another. In this way, when the insertion aid  2  is removed from the catheter head and disposed of, there is no risk of injury posed by the guide needle  6 .  
         [0030]     While various embodiments, including preferred embodiments, of the present invention have been described herein, it is contemplated that various modifications could be made without deviating from the spirit of the present invention. Accordingly, it is intended that the scope of the present invention be dictated by the appended claims.