INTRAVASCULAR DEVICE INCLUDING A CLIP FOR USE IN PREVENTING NEEDLE RETRACTION

Abstract: The invention provides a clip for use in preventing retraction of the tip of a tissue puncture needle within the cannula lumen of an intravascular device comprising a cannula having a tissue puncture needle disposed in the lumen thereof, as well as a said device including such a clip. The clip of the invention comprises a body member having a first portion adapted to be associated with an assembly comprising a tissue puncture needle at a portion of the assembly remote from the needle tip and, spaced from the first clip portion, a second clip portion engageable with the intravascular device to lock the needle relative to the cannula against movement permitting said retraction. Furth­ ermore, the second clip portion is releasable by radial movement away from the device which does not necessitate movement of the device away from the patient's body once venipuncture has been effected, thus minimising disturb­ ance of the device in situ.

Description: A CLIP FOR USE IN PREVENTING NEEDLE RETRACTION IN INTRAVASCULAR DEVICES AND DEVICES INCLUDING THE SAME The present invention relates to the prevention of needle retraction in intravascular devices and, in particular, to a clip for use in preventing needle retraction, and devices including the same. Intravascular devices are commonly used for supplying fluid to a patient or for the withdrawal or monitoring of blood. Thus, for example, they may be used to supply a drug on a continuous basis, for blood pressure measurement, or for extraction and return of blood in haemodialysis. In use of such devices it is customary to introduce a plastics cannula into a vein or artery by means of a metal introducing needle. The introducing needle is incorporated within the lumen of the cannula so as to act as means to effect tissue puncture and to introduce the cannula. After such puncture the needle is withdrawn leaving the cannula in situ to be coupled to suitable equipment for the required treatment or procedure. In such intravascular devices the hollow introducing needle may be bonded to a hub or coupling member serving as a finger grip, and at its sharpened distal end the needle protrudes beyond the cannula lumen. Tissue puncture is thus effected by that sharpened distal end, and permits the cannula to follow the needle until it too progresses to a second puncture of the blooci vessel. When entry to the blood vessel is verified by a "flashback" of blood through the hollow needle to :he transparent needle hub, the needle is withdrawn leaving the cannula disposed within the blood vessel to serve as the desired conduit into the patient's bloodstream. With such devices, a problem arises in use when the needle ub cannot be used as a finger grip. This may be the case, for example, when the needle and cannula are zoo long or the shape or constitution of the device make. gripping the needle via the needle hub cumbersome znd/or unstable. In such cases the operative may have tc transfer his or her grip tosa more suitable part of th#' device, for example, neare-r'to the needle tip to reduce the effective needle length. However, when the grip is transferred from the needle hub, for example, to the hub portion attached to the cannula, typically where that hub portion is of elastomeric material e.g. polyurethane, pressure on the needle tip caused by tissue resistance can overcome the thusreduced gripping force and, in turn, can cause the needle to retract within the lumen of the cannula. Thus, the sharp needle tip can be prevented from functioning in its necessary role of effecting initial tissue puncture. In U.S. Specification No. 4,314,555 there is described an intravascular catheter assembly including a location bar to restrain forward movement of the needle relative to the cannula, and to define the extent to which the needle is inserted into the cannula, so as to cause the distal end of the needle slightly to protrude from the distal end of the cannula. However, the disclosed assembly includes no means to prevent any rearward movement of the needle leading to needle retraction within the cannula. In British Specification No. 1,590,796 there is described needle restraining means to restrain relative axial movement in either direction between the cannula and the introducing needle. The disclosed restraining means fits over substantially the entire length of the flexible sleeve portion of the disclosed catheter assembly and connects said portion to the needle hub portion to restrain both forward and rearward movement of the needle (and thus to prevent needle retraction within the cannula). The restra#ng means also includes means enabling the selective release of the needle assembly to permit withdrawal of the needle assembly after venipuncture. However, in the specific embodiments disclosed in that British specification, the needle restraining means comprises various collar or like arrangements wholly surrounding the intravascular device. For the majority of such specific embodiments the restraining means must be released along an upper portion e.g. released by a tear strip portion running along the length of the restraining means, and then removed from beneath the intravascular device, i.e. from between the device and the adjacent portion of the patient's body. However, to effect such removal without disturbing the device, is in most circumstances extremely difficult, if not impossible. While it is perhaps possible with care to release the restraining means without disturbing the device, also to remove the restraining means without disturbance would appear to be impossible in most circumstances. Furthermore, while there is also disclosed an additional embodiment wherein a needle restraining collar is rotated to effect release, in that case the operation of releasing the restraining means would appear to cause undesirable disturbance of the in situ device. There is, therefore, a need to provide a means of restraining a tissue puncture needle to prevent retraction within the cannula of an intravascular device which means can be released to permit complete withdrawal of the needle from the cannula with the minimum of disturbance to the device once in situ. In the present invention we seek to provide a clip to effect a relatively simple and temporary locking of the needle relative to the cannula in order to avoid the serious inconvenience of needle retraction, which clip can easily be released without serious disturbance of the in situ device carrying the needle. Accordingly, the present invention provides a clip for use in preventing retraction of the tip of a tissue puncture needle within the cannula lumen of an intravascular device comprising a cannula having a tissue puncture needle disposed in the lumen thereof, which clip comprises a body member having a first portion adapted to be associated with an assembly comprising said tissue puncture needle at a portion of the assembly remote from the needle tip and, spaced from the first clip portion, a second clip portion engageable with the intravascular device to lock the needle relative to the cannula against movement permitting said retraction, the second clip portion being releasable by movement away from the device which does not necessitate movement of the device away from the patient's body once puncture has been effected. The clip of the present invention may be used with any intravascular device comprising a cannula and a needle assembly, the needle of which (at least initially) is disposed in the lumen of the cannula. However, while not being limited to such use, the clip is particularly useful in conjunction with a device comprising a cannula a hub portion associated with the cannula and with which the second portion of the clip can engage. For example, the clip is particularly useful in conjunction with devices of the Y-CAN type as described in British Patent Applications Nos. BO-18935, 80-20604 and 81-17245 (British Patent Specification No. 2,088,215B), and haemo'd'iaI'ysis catheters, for example, as described in British Patent Specification No. 2,075,347B. i In the clip of-'the invention, the first portion may be formed separately of or integrally with the needle assembly. Thus, for example, the first portion may be integral with or merely engageable with the needle assembly. Furthermore: the second clip portion may be engageable with tbf device in any manner which permits releasable engagfment, and release of the clip by movement thereof,:-away from the device in a manner such that there is no necessity to move the device away from the patient's bony. Preferably, the second clip portion comprises a pair of opposed arms engageable with the device on either side thereof and releasable therefrom by sideways ore upward movement relative to the adjacent portion of tEz patient's body. Preferably also, the first and seslJnd portions of the clip are arranged so that any second portion or portions can be released without detawnment of the first portion from the needle assembly. More Fteferably, the second clip portion includes a pair of opfosed arms which provide a pair of abutment faces intertngageable with face portions of the hub portion of the intravascular device whereby axial separation q: the cannula and needle is restrained until the said abutment faces are moved radially clear of the said face portions. In oft preferred embodiment of the invention the clip is o@@ for use as part of an intravascular device (typically for infusion) comprising a cannula and a hub portion having at the end of the hub portion remote from the cannila means for connection to a lock connector, typical) a luer lock or Record lock connector. In this embodir/)nt, the clip is formed as an integral part of the needle assembly and includes one or more second portions engageable with said luer lock or like lock connection- means. Typically, the luer lock or like lock connection means may comprise a pair of lugs, preferably of wedgeshaped form, upstanding from the outer surface of the proximal end of the hub portion. Such lugs are formed so that one surface faces towards the needle tip, and that surface is preferably at a helical angle corresponding to the helical angle of the luer lock or like lock connector. For use with a needle assembly including such connection means, the clip preferably includes second portions engageable with said lugs comprising a pair of arms disposed at opposite extremes of the body member moveable into and out of engagement with said lugs, the arms including at one end opposed tip portions adapted to interengage with the lugs at the said one surface thereof. More preferably, the arms are pivotably mounted at opposite extremes e.g. on either side, of the body member, and are themselves grippable at their other ends remote from the opposed tip portions so as to provide for the necessary movement into and out of engagement with said lugs. Also, the opposed tip portions typically each comprise a first inwardly depending flange adapted to interengage with the lugs at said one surface and a second inwardly depending flange adapted to interengage with a lug end face to prevent rotation of the clip in use. In a second embodimeut, particularly for use with a haemodialysis catheter comprising a cannula and a hub portion attached to the cannula, the clip comprises a body portion having at or adjacent one end means such as a pair of opposed depending arms engageable with a needle assembly, and at or adjacent its other end a pair of opposed depending arms engageable with the hub portion of the catheter, the said means being arranged to permit the said arms engageable with the hub portion to move into and out of engagement. Preferably, with such a clip the needle assembly is formed to include a pair of trunnion pins upstanding on either side of a portion of the assembly serving as a finger grip, and the clip is formed with an aperture in each of a first pair of opposed arms so that they can be sprung over and thus pivotably mounted on the trunnion pins. By such means, the clip can be mounted so that it may be pivotted into and out of a locking position, and the remaining pair of arms may be formed so as releasably to grip the hub portion attached to the cannula, preferably immediately in front of a shoulder portion thereof formed in the hub portion and facing the cannula, and to abut the shoulder portion to prevent needle retraction. Typically, such a shoulder portion will be formed between the cannula and any connection means, e.g. luer, luer lock or like lock connection means, at the proximal end of the hub portion. The clip of the invention may be formed of any suitable resilient material. Preferably, however, the clip is formed of a synthetic plastics material, for example, nylon or polypropylene. Furthermore, where the clip is an integral part of the needle assembly at least the portion of the assembly containing the lumen adjacent the non-distal needle end should be transparent so as readily to show "flashback". It is to be understood that the invention also includes an intravascular device including a clip as defined and described herein. The clip of the invention, and devices including such a clip, will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a side view of one form of clip in accordance with the invention; Figure 2 is a front view of the clip of Figure 1; Figure 3 shows the clip of Figure 1 as part of an intravascular device assembly; Figure 4 is a side view of another form of clip in accordance with the invention; Figure 5 is a front view of the clip of Figure 4; and Figure 6 shows the clip of Figure 4 as part of an intravascular device assembly. Referring to Figures 1 and 2, the clip shown comprises a body member 11 integral with a transparent needle hub 12 having a lumen 13. The needle hub 12 includes on either side at one end 14 luer lock or like lock connector lugs 15 (only one shown) and at its other end 16 the hub is attached to an end 17 of a needle 18. The body member 11 carries mounted thereon and on opposite sides of the needle hub 12 a pair of opposed arms 19 and 20. The arms 19 and 20 are mounted on the body member with a tip portion 21 and 22 respectively of each arm directed towards the end 16 of the needle hub, and with a finger grippable portion 23 and 24 respectively of each arm directed towards the end 14 of the needle hub. The arms 19 and 20 are formed with the body member 11 e.g. as an integral plastics moulding, typically of a resilient plastics material such as nylon or polypropylene, whereby they are pivotable about the body member, and so that when the portions 23 and 24 are gripped and depressed towards the hub 12 the tip portions 21 and 22 are raised away from the hub 12. The end 16 of hub 12 is tapered so as to fit within lumen 31 at the proximal end of a hub portion 25 of an intravascular device comprising the hub portion and a cannula 26 attached thereto (see Figure 3). Adjacent end 16 the tip portions 21 and 22 include a first flange 27 and 28 respectively engageable with one surface of a Luer or like lock lug to provide a pair of abutment faces whereby axial separation of the cannula and needle is restrained until the faces are moved radially clear of each other. Also, each tip portion includes a second flange 29 and 30 respectively normal to the first flange engageable with an end face of such a lug to prevent rotation of the clip when locked on said proximal end of the hub portion 25. As shown in Figure 3, in use the needle 18 is disposed within lumen 31' of cannula 26,. with the tapered end 16 of hub 12 fitted within the lumen at the proximal end of the hub portion 25 of the intravascular device. In that disposition, flanges 27,30 and 28,29 respectively of tip portions 21 and 22 are in locking engagement with front and end faces of lugs 32 and 33, and thereby prevent relative movement (permitting needle retraction) between the cannula 26 and the needle 18r as well as rotation of the hub 12. Thus, wherever the assembly may be gripped, force may be applied to sharpened tip 34 of needle 18 via that grip without the tip 34 retracting within the lumen 31 of cannula 26. Then, subsequent to tissue puncture, and once the cannula is in situ within the patient's blood vessel (as shown by blood "flashback" into the hub 12), portions 23 and 24 may be gripped and depressed to release the clip so that the needle 18 may be withdrawn from the cannula 26. The luer lock lugs may then be used to connect the cannula 26 and hub portion 25 to a syringe or other means of effecting the desired treatment. Of course, as is known in the art, in order to permit needle withdrawal without spillage of blood, the hub portion 25 may include a self-sealing rubber or like seal (not shown) either within the hub portion or adjacent its proximal end. Referring to Figures 4 and 5, the clip there shown comprises a body member 41 having at one end 42 a first pair of opposed arms 43 and 44. The arms 43 and 44 depend downwardly from the body member 41 and include through apertures 45 and 46 respectively. Remote from arms 43 and 44 the body member 41 includes a second pair of opposed arms 47 and 48 between them defining a recess 49 within which a hub portion of an intravascular device can be accommodated. In addition, at its end 50 beyond arms 47 and 48 the body member 41 includes a finger grippable nose portion 51 having ridges 52 to prevent slippage when gripped by a finger tip. Again, the clip may be formed of a resilient plastics material such as nylon or polypropylene. The clip of Figures 4 and 5 is adapted for use with a needle assembly as shown in Figure 6. As there shown, the needle assembly comprises a needle 53 and a transparent needle hub 54 including on each side trunnion pins 5-5 (only one shown). In use the first pair of opposed arms 43 and 44 are sprung over the trunnion pins 55 so that the pins are accommodated in apertures 45 and 46 respectively, whereby the clip is pivotably mounted on the needle hub 54. When thus mounted on the needle hub, and with the needle 53 disposed within lumen 57 of cannula 58, whereby sharpened needle tip 59 protrudes beyond end 60 of the cannula 58, the clip can be depresssed onto hub portion 61 attached to the cannula 58, so that arms 47 and 48 move apart and the hub portion 61 is sprung into the recess 49. Then, by virtue of the presence of shoulder 62 on hub portion 61, abutting surfaces of the shoulder 62 and the arms 47 and 48 lock the needle 53 relative to the cannula 58 to prevent rearward movement which might permit tip 59 to retract within the lumen. As before, once "flashback" within needle hub 54 is seen, and tissue puncture is thereby confirmed, the clip may be released by applying finger pressure to nose portion 51 at ridges 52 to release hub portion 61 from recess 49. Once the clip is thus released the needle may be withdrawn to permit the desired connection to hub portion 61 to be effected by removal of plug 63. Again, the hub portion 61 may be adapted to accommodate a luer connector or may include luer lock or like lock lugs (not shown) at its proximal end beyond the shoulder 62. Also, the hub portion may again include a self-sealing rubber or like seal (not shown) either within the hub portion or adjacent its proximal end to permit needle withdrawal without blood spillage. As will be appreciated from the above specific description, the present invention provides a clip which can prevent needle retraction while at the same time being releasable with minimum disturbance to the in situ device. Also, because the clip as described is both releasable from and returnable to the locking configuration even while the device is in use, any initial error in effecting puncture can be adjusted by releasing the clip, partially withdrawing the needle, returning the needle, and relocking the clip. This permits a flexibility of function and puncture technique not available with prior art devices.

Claims: CLAIMS 1. A clip for use in preventing retraction of the tip of a tissue puncture needle within the cannula lumen of an intravascular device comprising a cannula having a tissue puncture needle disposed in the lumen thereof, which clip comprises a body member having a first portion adapted to be associated with an assembly comprising said tissue puncture needle at a portion of the assembly remote from the needle tip and, spaced from the first clip portion, a second clip portion engageable with the intravascular device to lock the needle relative to the cannula against movement permitting said retraction, the second clip portion being releasable by movement away from the device which does not necessitate movement of the device away from the patient's body once puncture has been effected. 2. A clip according to claim 1, wherein the second clip portion comprises a pair of opposed arms engageable with the device on either side thereof and releasable therefrom by sideways or upwards movement relative to the adjacent portion of the patient's body. 3. A clip according to claim 1 or claim 2, wherein the first and second portions of the clip are arranged so that any second portion or portions can be released without detachment of the first portion from the needle assembly. 4. A clip according to any one of the preceding claims, wherein the second clip portion includes a pair of opposed arms which provide a pair of abutment faces interengageable with face portions of the hub portion of the intravascular device whereby axial separation of the cannula and needle is restrained until the said abutment faces are moved radially clear of the said face portions. 5. A clip according to any one of the preceding claims, formed separately of or integrally with the needle assembly. 6. A clip according to any one of the preceding claims for use as part of -an intravascular device comprising a cannula and a hub portion having at the end of the hub portion remote from the cannula means for connection to a lock connector, wherein the clip is formed as an integral part of the needle assembly and includes one or more second portions engageable with said lock connection means. 7. A clip according to claim 6, wherein the lock connection means comprise a pair of lugs upstanding from the outer surface of the proximal end of the hub portion with one surface thereof facing towards the needle tip, and the clip includes second portions engageable with said lugs comprising a pair of arms disposed at opposite extremes of the clip body member moveable into and out of engagement with said lugs, the arms including at one end opposed tip portions adapted to interengage with the lugs at the said one surface thereof. 8. A clip according to claim 7, wherein the arms are pivotably mounted at opposite extremes of the body member, and are themselves grippable at their other ends remote from the opposed tip portions so as to provide for the necessary movement into and out of engagement with said lugs. 9. A clip according to claim 7 or claim 8, wherein the tip portions each comprise a first inwardly depending flange adapted to interengage with a lug at said one surface and a second inwardly depending flange adapted to interengage with a lug end face to prevent rotation of the clip in use. 10. A clip according to any one of claims 1 to 5 for use with a haemodialysis catheter comprising a cannula and a hub portion attached to the cannula, the clip having a body portion including at or adjacent one end means such as a pair of opposed depending arms engageable with the needle assembly, and at or adjacent its other end a pair of opposed depending arms engageable with the hub portion of the catheter, the said means being arranged to permit the said arms engageable with the hub portion to move into and out of engagement. 11. A clip according to claim 10 for use with a needle assembly formed to include a pair of trunnion pins upstanding on either side of a portion of the assembly serving as a finger grip, the clip being formed with a first pair of opposed arms each including an aperture so that they can be sprung over the trunnion pins and the clip thereby pivotably mounted on the needle assembly hub portion. 12. A clip according to claim 11, wherein the device includes a shoulder in the catheter hub portion facing the cannula and the remaining pair of arms are formed so as releasably to grip the hub portion of the catheter immediately in front of the shoulder portion, and to abut the shoulder portion to prevent needle retraction. 13. An intravascular device assembly including a clip according to any one of the preceding claims. 14. An intravascular device assembly according to claim 13 including the device features of any one of claims 6 to 9 or 10 to 12.

Inventors: WALLACE, HENRY GEORGE
Applicants: H.G. WALLACE LIMITED
Application year: 1985
Main classification: A61M5
IPC codes: A61M39