Needle protector

Abstract: The present invention provides an assembly of an intravenous cannula insertion device (21) and an elongate needle protector (1), said protector comprising a slotted tube (2), a needle (10) and a needle hub (19), said needle hub comprising a protrusion (12.33) extending through said slot to allow the needle and needle hub assembly to be slidable within said protector, a cannula hub (21) operatively inter-engagable with said needle hub within said protector, whereby said needle hub and said cannula hub are extensible together from the protector to allow i.v. insertion of a cannula (20), and wherein said assembly includes a retraction prevention means (7) for preventing retraction of the cannula hub (21) after it has been fully extended whereby the cannula hub (21) remains interlocked with the needle hub (19) when fully extended until released from the assembly by a operation of a release means (15.23). The invention provides means whereby an introducer needle (10) must be withdrawn from the cannula hub before the cannula hub can be separated from the needle protector (1).

Description: Field of the Invention The present invention relates to a needle protector. Particularly this invention relates to i.v. catheter assemblies adapted to protect the sharp tip of a needle after use to prevent accidental injury from used needles. Background of the Invention Typical over-the-needle i.v. catheter assemblies require the removal and disposal of a contaminated needle after the needle tip and catheter have been inserted into a blood vessel of a patient. Since at the time a needle is withdrawn, the user has other priorities, needles tend to be temporarily discarded for later disposal. This leads to the possibility of accidental scratching or pricking of health personnel which can lead to inadvertent infection with viruses such as HIV and hepatitis. For this reason various attempts have been made to provide catheter assemblies incorporating various means for preventing a needle tip from coming into inadvertent contact with a user once the cannula hub of the catheter assembly has been left in situ in the patient. One problem experienced with assemblies of this type is to provide a needle protector which protects the needle both before and after use by using the same elongate protector body. This body should allow a needle and needle hub to be assembled with a cannula and cannula hub within the protector body, said assembly being extended by sliding the same in the body to a position where the cannula hub is free of the protector as, for example, when inserted into a patient. The needle is then retracted within the body of the needle protector for safety. Prior Art systems, however, allow the cannula hub and protector to be separated without initiating the withdrawal of the needle, thereby allowing the needle to become exposed if the device is not utilised properly. In US-A-5019049, there is described an assembly of an intravenous cannula insertion device and an elongate needle protector, said protector comprising; a slotted tube, a needle and needle hub, said hub comprising a fin protruding through said slot to allow the needle and needle hub assembly to be moved within said protector, a cannula hub operatively inter-engagable with said needle hub within said protector, whereby said needle hub and said cannula hub are slidable together in the protector to allow i.v. insertion of the cannula and wherein said assembly includes retraction prevention means for preventing the retraction of the cannula hub after it has been fully extended for use. Summary of the Invention The invention provides in an assembly of an intravenous cannula insertion device and a needle protector (1) said protector comprising a tube having a slot (2), a needle (10) and needle hub (19), said needle hub comprising a protrusion (12,32) extending through said slot (2) to allow the needle and needle hub to be slided within said protector, said protrusion being hinged about a pivot (16,36) to the needle hub, and said intravenous cannula insertion device comprising a cannula hub (21) and a cannula (20), said cannula hub (21) being operatively inter-engagable with said needle hub within said protector, whereby said needle hub and said cannula hub are extensible together from the protector to allow i.v. insertion of the cannula (20), wherein said assembly includes retraction prevention means (7) for preventing retraction of the cannula hub (21) after it has been fully extended, and wherein the needle is retractable into the needle protector prior to disengagement of the cannula hub from the needle protector characterised in that the protrusion (12,32) and the cannula hub (21) are provided with complementary releasable interlocking means (15,23), and the protrusion is provided with at least one lug (13,33) adapted to slide along the slot (2), whereby the protrusion (12,32) is prevented by said lug (13,33) from rotational movement about the pivot (16,36) until the protrusion (12,32) is in the extended position In one embodiment, the protrusion (12,32) has a first pressure face for sliding the needle hub (19) and the cannula hub (21) along the slot (2), and a second pressure face for releasing the interlocking means (15,23) by the application of pressure thereon. In another embodiment, the protrusion (12,32) has a single pressure face for sliding the cannula hub and needle hub along the slot (2), and for releasing the interlocking means (15,23) by the application of pressure thereon. The assembly may also include a secondary release means (5,22) operable subsequent to the interlocking means (15,23) being released to allow the cannula hub (21) to be freed from the protector (1). The secondary release means (5,23) can be actuated by rotational movement of the needle protector (1) relative to the cannula hub. The protrusion (12,32) may be spring biased to an interlock position by a spring (14), and provided with a detent (15) for inter-engagement in said interlock position with a tab or pawl (23) on the cannula hub (21). In one embodiment, the lug (13) is adapted to ride upon a rail (4) extending along a portion of the length of the slot (2) of the needle protector (1). In another embodiment, the lug (13) is adapted to slide internally of the slot (2). Description of the Drawings The invention will now be described, by way of illustration only, with reference to the accompanying drawings wherein; Figure 1 shows a side elevation from above of an assembly of the invention; Figures 2 and 2a show respectively vertical and horizontal cross sections through a needle protector in accordance with the present invention, Figure 3 shows a side elevation of the needle and hub for sliding co-operation in the assembly in the Figure 1, Figure 4 shows a side elevation of a cannula and cannula hub for sliding co-operation in the assembly of Figure 1, Figure 5 shows a side elevation of an assembly of the elements of Figures 4 and 5 in operative interengagement, Figure 6 shows a side elevation of the elements of Figures 3 to 5 in operative interengagement within the needle protector, in the at rest position, Figure 7 shows side elevation of elements of Figures 3 and 4 in the extended position, Figure 8 shows a side elevation of elements of Figures 3 to 5 with the needle hub withdrawn, Figure 9 shows a side elevation of the assembly in Figure 1 with the cannula hub separated, Figure 10 shows a side elevation from above of a further embodiment of the invention, Figure 11 shows a front view of the arrangement of Figure 10, Figure 12 shows a side view of the arrangement of Figure 10, and Figure 13 shows a section along a line "A A" of Figure 10. Description of Preferred embodiments of the Invention Figure 1 of the accompanying drawings shows a needle protector (1) having an elongate body is formed of a plastics material with an elongate slot (2) along its intended upper edge. The needle protector (1) is adapted to accommodate within its hollow interior, a cannula and cannula hub (21) and a needle hub assembly (19) including a needle hub fin (12). The arrangement of Figure 1 is shown in its at rest condition as may also be seen in Figure 6. The needle protector body (1) is moulded of a resilient plastics material and as best seen in Figures 2 and 2a provided with an elongate slot (2) extending from a closed proximal end to an open distal end. The distal end of the protector (1) is provided with a closed slit (3a) formed by a pair of inwardly directed cheeks (3). The needle protector is formed of a plastics material which is sufficiently resilient to allow the cheeks (3) to be prised apart to open the slit and allow the cannula hub fin to pass therethrough. The needle protector (1) terminates at its distal end with a pair of opposed luer lugs (5) which generally form the ovoid end surface of the needle protector (1), and a pair of opposed internal rails (7) extending generally parallel to the slot (2) and generally over the portion of the distal end of the needle protector body (1) adjacent the cheeks (3). The needle protector (1) is also provided with a pair of longitudinally extending rails (4) which extend over a major portion of the proximal end of the slot (2) for purposes which will be elucidated later. Disposed toward the proximal end of the needle protector body (1) are a pair of inwardly directed non-return latches (6). The sides of the needle protector slot (2) are also provided with inwardly directed locating lugs (8) for the purpose of retaining the assembly in its at rest condition prior to use. The internal floor of the hollow needle protector body is provided adjacent the locating lugs (8) with a needle protector stop (9). It will be appreciated that the needle protector body (1) is formed of a cheap plastics material since it exists essentially to protect the catheter needle prior to use and to be safely discarded subsequently. With reference to Figures 3 to 5. Figure 3 shows a needle and needle hub assembly for operative interconnection with a cannula and cannula hub assembly of Figure 4; said assembly is shown in the inter-engaged condition in Figure 5. In Figure 3, the needle (10) extends from a needle hub (19) in accordance with the usual practice in the Art. The needle hub (19) is provided with a flashback chamber (19a) shown in dotted lines in Figure 3. The body of the needle hub (19) is also provided towards its proximal end with a pair of detents (11) adapted in use to co-operate with detents (6) in the needle protector (1). The needle hub (19) is also provided on its uppermost surface with a needle hub fin (12) conjoined to the body of the needle hub (19) by means of a generally centrally located hinge (16). The needle hub fin (12) is also provided towards its forward end with a downwardly directed latch (15) and, remote from said latch and approximately equidistant from the hinge (16), with a moulded spring tab (14) adapted to forwardly bias the fin (12). The fin (12) is also provided on either side with perpendicularly directed lugs (13) adapted in use to ride along the top edge of the rails (4) formed adjacent the slots (2) of the needle protector (1). With reference to Figure 4, the cannula (20) is provided with a cannula hub (21). The cannula hub (21) is provided on its upper surface with a cannula hub fin (24) provided, in this particular instance, with a side tube for the cannula hub (21). The upper surface of the cannula hub (21) is provided to the rear of and adjacent, the fin (24) with a tab or pawl (23) for interengagement with the latch (15). The cannula hub (21) is provided with a cannula hub bore (21a) for accommodation of the needle (10) in accordance with the usual practice in this art. A sealing bung (26) is provided in the cannula bore (21a) for the usual purposes. The assembly is more generally shown in Figure 5 wherein the fin (12) is biased by the spring bias (14) into interengagement with the latch (15). With reference to Figures 6 to 9, it will be seen that the arrangement shown in Figure 5 is disposed in its at rest condition in the needle protector body (1). The tip of the needle (10) is disposed within the needle protector body, while the rear of the cannula and needle hub assemblies is adjacent to, but forward of, of the non-return latches (6) disposed at proximal end of the needle protector body. It will also be noted, with reference to Figure 6, that a needle protector stop (9) is upwardly disposed in the floor of the needle protector body (1) such that it contacts the rear end of the cannula hub (21). The needle hub (19) is provided, on its lowermost surface with a longitudinal channel (17) to accommodate the stop (9). Accordingly the assembly cannot slide backwardly while the needle hub assembly is interengaged with the cannula hub assembly. Further, locating hubs (8) locate the forward edge of the needle hub assembly thereby preventing the assembly from sliding forwardly until a significant pressure is exerted on the rearward face of the needle hub fin (12). The arrangement of Figure 6 is provided in a sterile bag for protection before use. In Figure 7 it will be seen that the needle hub fin has been driven forwardly along the rail (4) to its extended position. In doing so, the lugs (13) have cleared the forward sloping end faces (4a) and of the needle protector body (1) such that now the fin (12) can rock anti-clockwise by means of digital pressure applied to the rear of the hinge (16). The needle hub assembly can travel as far as the forward end of the slot (4) to the beginning of the closed slit (3a). In condition as shown in Figure 7, the needle (10) extends from the cannula (20) so that the cannula can be inserted into the patient in the usual way. With the cannula successfully inserted and confirmed by means of the flash chamber (19a), it is then necessary to withdraw the introducer needle (10) as shown in Figure (8). The withdrawal is effected by releasing the latch (15) against the spring bias of the spring (14) and withdrawing of the needle rearwardly until the detents (11) engage with the non-return latch (6) so that the needle is beady for disposal. In this condition the cannula hub (21) is still inter-engaged with the forward face of the needle protector (1) because luer lugs (22) cannot be withdrawn past the luer lugs (5) without relative rotation of the needle protector relative to the cannula hub (21). With this relative rotation completed, it is then possible to withdraw the needle protector from the cannula leaving the cannula in situ without the possibility of needle-stick. The final arrangement of parts is to be seen in Figure 9. The arrangement of the internal proximal latches prevents the needle from being extended as there are no means of releasing them once they are locked in place, and further the needle and cannula hubs are locked together as a unit and cannot be separated until they are extended from the needle protector (1). A further important feature of this device is that the needle protector (1) remains locked to the cannula until the needle (10) is partially withdrawn (by releasing the tab on the cannula hub) thus providing a handle or gripping arrangement to facilitate insertion of the needle into the patient. In a further form of the invention shown in Figures 10 to 13, an alternative form of locking the protrusion is shown. It has been found that a number of surgeons like to bend the needle and the cannula assembly before insertion into the patient. This is to provide an angle for easier insertion of the device into a vein. As a result, when the needle is retracted into the needle protector, instead of being aligned straight in the needle protector (1), its tip is likely to spring out from the slot because it is formed of a hardened metal and is inherently spring-like. To overcome this problem, an alternative design is shown in Figures 10 to 13, which in effect requires relative rotation of the operational position of the needle protector through 90 degrees so that the slot (2) is positioned in the horizontal rather than the vertical. Accordingly, in Figures 10 to 13 like parts have been designated with like numbers and will not be described further except in so far as they impinge on the modus operandi of the device of Figure 10. With particular reference to Figure 10, the needle protector body (1) is formed, as previously with a slot (2), although in the present instance the rails (4) have been removed. A needle hub (39) is formed with a pair of internally extending lugs (33) (see Figure 13), which are conjoined in turn to a profiled thumb grip (32) (which is substituted for the fin (12)). The profiled thumb grip (32) is provided with an eccentric hinge (36) and with a detent (35) to inter-engage with a corresponding pawl (23) on the cannula hub (21). Additionally, the needle protector tube is provided diametrally from the profiled thumb grip (32) with a profiled finger grip (30). In the at-rest position, as shown in Figure 10 and 12 as ghost lines, the needle hub and cannula hub assembly are withdrawn to their protective positions prior to use. In use, the profiled thumb grip (32) is urged along slot (2), taking with it the cannula hub (21) in the fashion described with reference to Figures 1 to 9. At the point when the forward end of the needle hub extends beyond the end of the protector (1), the lugs (33) are cleared from retention within the slotted protector (1). In this last position the profiled thumb grip (32) may be rocked about the eccentric hinge (36) thereby disengaging detent (35) from pawl (23) on the cannula hub; allowing the cannula hub to be disengaged. This disengagement may either be direct, or may be via a secondary disengagement means which requires relative rotational movement if desired. It will be appreciated that the profiled thumb grip (32) cannot rotate about the hinge (36) until the lugs (33) have cleared the end of the needle protector tube. By moulding a thumb grip or pad on the opposite side of the slot at the distal end of the needle protector and said grips being an appropriate ergonomic shape for ease of grip and operation, it is more readily possible to utilise the device in the orientation shown in Figure 10 so that when the cannula (20) and the introducer needle (10) are bent prior to insertion, and subsequently withdrawn, the needle will not tend to protrude from the slot (2). Accordingly the invention provides an assembly of an intravenous cannula insertion device and an elongate needle protector.

Claims: An assembly of an intravenous cannula insertion device and a needle protector (1) said protector comprising a tube having a slot (2), a needle (10) and needle hub (19), said needle hub comprising a protrusion (12,32) extending through said slot (2) to allow the needle and needle hub to be slided within said protector, said protrusion being hinged about a pivot (16,36) to the needle hub, and said intravenous cannula insertion device comprising a cannula hub (21) and a cannula (20), said cannula hub (21) being operatively inter-engagable with said needle hub within said protector, whereby said needle hub and said cannula hub are extensible together from the protector to allow i.v. insertion of the cannula (20), wherein said assembly includes retraction prevention means (7) for preventing retraction of the cannula hub (21) after it has been fully extended, and wherein the needle is retractable into the needle protector prior to disengagement of the cannula hub from the needle protector characterised in that the protrusion (12,32) and the cannula hub (21) are provided with complementary releasable interlocking means (15,23), and the protrusion is provided with at least one lug (13,33) adapted to slide along the slot (2), whereby the protrusion (12,32) is prevented by said lug (13,33) from rotational movement about the pivot (16,36) until the protrusion (12,32) is in the extended position. An assembly according to Claim 1 wherein the protrusion (12,32) has a first pressure face for sliding the needle hub (19) and the cannula hub (21) along the slot (2), and a second pressure face for releasing the interlocking means (15,23) by the application of pressure thereon. An assembly according to Claim 1 wherein the protrusion (12,32) has a single pressure face for sliding the cannula hub and needle hub along the slot (2), and for releasing the interlocking means (15,23) by the application of pressure thereon. An assembly according to any preceding Claim, further including a secondary release means (5,22) operable subsequent to the interlocking means (15,23) being released to allow the cannula hub (21) to be freed from the protector (1). An assembly according to Claim 4, wherein the secondary release means (5,23) is actuated by rotational movement of the needle protector (1) relative to the cannula hub. An assembly according to any of the preceding Claim, wherein the protrusion (12,32) is spring biased to an interlock position by a spring (14), and is provided with a detent (15) for inter-engagement in said interlock position with a tab or pawl (23) on the cannula hub (21). An assembly according to any preceding Claim, wherein said lug (13) is adapted to ride upon a rail (4) extending along a portion of the length of the slot (2) of the needle protector (1). An assembly according to any of Claims 1 to 7 wherein the said lug (13) is adapted to slide internally of the slot (2).

Inventors: WALLACE GEORGE, WALLACE, GEORGE
Applicants: SMITHS INDUSTRIES PLC
Application year: 1992
Main classification: A61M25
IPC codes: A61M5, A61M25