Needle assembly equipped with valve

Abstract: A needle assembly equipped with a valve (15) comprising an outer needle member having an outer needle hub (12) fixed to the proximal end of an outer needle (10) and a valve (15) mounted to close the inner passage (11) of the outer needle hub (12), and an inner needle member having an inner needle (13) which is adapted to be inserted into the outer needle (10) through the outer needle hub (12) to such an extent that only the tip por­ tion (13a) of the inner needle (13) projects outward through the tip of the outer needle (10). The outer needle hub (12) includes an enlarged hollow portion formed at a portion thereof which is located inner side of the valve-mounting portion, the inner diameter of the enlarged hollow portion being larger by at least twice a compressed thickness of the valve as it is pressed by the attachment of the rod-like member or the tubular member than that of an inner diameter of a portion of the outer needle hub (12) which is located outer side of the valve-mounting portion and in which the rod-like member or the tubular member is fitted, the enlarged hollow portion presenting an relief for a deformed por­ tion of the valve (15) when the rod-like member (16) or the tubular member is inserted through the valve (15).

Description: The present invention relates to a needle assembly equipped with a valve, which is adapted to be used for infusing blood or liquid into a blood vessel. Generally, the infusion of blood or liquid into a blood vessel is conducted by piercing a needle assembly comprising an inner needle member fitted integrally in the outer needle member into the blood vessel, withdrawing only the inner needle member from the blood vessel, and then connecting the hub of the outer needle member with a connector of, for example, a blood-infusion set (or a liquid-infusion set). In this case, blood tends to leak out of the proximal opening of the hub of the outer needle member during the step of withdrawing the inner needle member, or during the step of connecting the hub of the outer needle member to the connector. In order to prevent such a leakage of blood, an outer needle member provided on its hub portion with a valve has been conventionally proposed. Fig. 1 shows an example of such an outer needle member equipped with a valve. This outer needle member comprises an outer needle 1, an outer needle hub 3 fixed to the proximal end of the outer needle 1 and having a passage 2 communicating with a longitudinal hollow portion 1a of the outer needle 1, and a film-like valve 4 mounted at a middle portion of the passage 2 of the outer needle hub 3. When in use, an inner needle member (not shown) comprising an inner needle and an inner needle hub fixed, to the proximal end of the inner needle is fitted in the outer needle member thereby forming a needle assembly, which is then pierced into a blood vessel. Thereafter, the inner needle member is withdrawn from the outer needle member, leaving the outer needle member indwelled in the blood vessel. In this case, even if the inner needle member is withdrawn from the outer needle member, any leakage of blood can be effectively prevented due to the presence of the valve 4. However, when a connector of for example an infusion set is fitted in the outer needle hub 3,the connector is kept within the outer needle hub 3 as shown in Fig. 2. Namely, only the tip portion 5a of connector 5 is grasped by the valve 4 leaving proximal end portion 5b kept free to move due to the presence of the valve 4, thereby rendering the connector to be fixed in the outer needle hub 3 in a very unstable state as a whole. As a result, the connector 5 is merely weakly fitted in the outer hub 3 so that the connector is more likely to be accidentally detached if it is carelessly handled. EP-A-0 316 096 discloses a hemostasis valve which includes a longitudinally extended housing having first and second opposing open ends, a cap means enclosing the first end and having an opening to permit insertion of a catheter into the longitudinally extended housing; and a one-piece seal means located within the central passage of the longitudinally extended housing. The seal means is provided with a sealing neck and sealing exit lips arranged so that the catheter may be readily inserted through the sealing neck and out the sealing exit lips. The second end of the valve housing is attached to a sheath which is inserted into the vasculature. By employing this hemostasis valve, it is possible to use different catheters which may vary in diameter. DE-C-3809127 discloses a cannula for insertion of a catheter which comprises a end cap, a valve housing, and a seal closing the passage between the cap and the inside of the valve housing. The inner hollow portion within the valve housing is larger than the inner hollow portion within the cap. The valve is comprised of a flexible gasket and a spring. When a tubular member is inserted through the valve, a portion of the gasket is deformed and is urged against the outer surface of the tubular member by the action of the spring. In both documents, the enlarged inner portions are such that the valve will not expand against the interior wall of these enlarged inner portions. Accordingly, an object of the present invention is to provide a needle assembly equipped with a valve, which can be strongly and liquid-tightly connected to a connector of blood or liquid infusion set. In order to solve the problems of the prior art as mentioned above, measures are taken according to the present invention to form an enlarged hollow portion at a portion of the hub of the outer needle member which is located inner side of the valve-mounting portion, the inner diameter of the enlarged hollow portion being larger than an inner diameter of a portion of the hub which is located outer side of the valve-mounting portion. This enlarged hollow portion presents a relief for the valve when a connector of a blood or liquid infusion set is connected to the outer needle hub. Accordingly, the present invention provides a combination of a needle assembly and a rod-like member or tubular member, said needle assembly being equipped with a valve and comprising an outer needle member including an outer needle (or cannula and the like), an outer needle hub fixed to the proximal end of the outer needle and having an inner passage communicating with the outer needle, and a valve mounted to close the inner passage of the outer needle hub and being capable of allowing a rod-like member or a tubular member to pass therethrough, the outer needle hub including an enlarged hollow portion formed in a portion thereof which is located inner side of the valve-mounting portion and said rod-like member or tubular member having an outer diameter which is substantially the same as an inner diameter of a passage of a portion of the outer needle hub which is located outer side of the valve-mounting portion, characterized in that the inner diameter of the enlarged hollow portion is larger by twice a compressed thickness of the valve as it is pressed by the attachment of the rod-like member or the tubular member than the inner diameter of said portion of the outer needle hub which is located outer side of the valve-mounting portion and in which the rod-like member or the tubular member is fitted, the enlarged hollow portion forming a relief for receiving said deformed portion of the valve under compression when the rod-like member or the tubular member is inserted through the valve. It is preferable that said portion of the inner wall surface of the outer needle hub which is located outer side of the valve-mounting portion is formed into a luer taper, thereby improving the fitting strengh and liquid-tightness of the rod-like member (such as a connector of a blood or liquid infusion set) or the tubular member relative to the outer hub. When using the needle assembly as constructed above, the inner needle hub is fitted in the outer needle hub, and then pierced into a blood vessel. Then, the inner needle member is withdrawn from the blood vessel as well as from the outer needle member, and a connector of for example a blood or liquid infusion set is fitted in the outer needle hub. At this moment, the circumferential portion of the valve is bent inward by the insertion of the distal portion of the connector. However, this bent circumferential portion of the valve is allowed to escape into the enlarged hollow portion of the outer needle hub, so that the proximal end portion of the connector can be hermetically settled on the inner wall of the proximal portion of the outer needle hub. As a result, the connector can be fitted in the outer needle hub with a sufficient fitting strength. This invention can be more fully understood from the following detailed description when taken in conjunction with the accompanying drawings, in which: Fig. 1 is a sectional view showing an example of the outer needle member equipped with a valve according to the conventional needle assembly; Fig. 2 is a partial sectional view of the outer needle member shown in Fig. 1, to which a connector of a blood or liquid infusion set is connected; Fig. 3 is a partial sectional view of a needle assembly according to the present invention; Fig. 4 is a sectional view of the needle assembly of Fig. 1, wherein the inner needle and inner needle hub are withdrawn therefrom; Fig. 5 is a perspective view of a valve to be used in the present invention; Fig. 6 is a side view of the valve shown in Fig. 5; and Fig. 7 is a partial sectional view of the outer needle member shown in Fig. 4, to which a connector of a blood or liquid infusion set is connected. This invention will be further explained with reference with the example shown in Figs. 3 to 7. Fig. 3 illustrates a partial sectional view of a needle assembly according to the present invention, wherein the needle assembly comprises an outer needle 10, an outer needle hub 12 fixed to the proximal end of the outer needle 10 and having an inner passage 11 communicating with the outer needle 10, an inner needle 13 which is adapted to be inserted into the outer needle 10 through the outer needle hub 12 to such an extent that only the tip portion 13a of the inner needle 13 projects outward through the tip of the outer needle 10, an inner needle hub 14 fixed to the proximal end of the inner needle 13 and adapted to be fitted in the outer needle hub 12, and a valve 15 mounted to the outer needle hub 12, closing the inner passage of the outer needle hub 12 and being capable of allowing a rod-like member (for example a connector of blood or liquid infusion set) or a tubular member to pass therethrough. To be more specific, the outer needle hub 12 comprises a distal portion 12a and a proximal portion 12b, each connected together by being fitted to each other. The valve 15 is held between these connected portions of the distal portion 12a and the proximal portion 12b by the circumferential portion thereof. The inner diameter "D" of the distal portion 12a near the mounting portion of the valve 15 is enlarged as compared with the inner diameter "d" of the proximal portion 12b near the mounting portion of the valve 15 (see Fig. 4). Therefore, when a connector of a blood or liquid infusion set is fitted in the outer needle hub 12 as explained later, this enlarged portion (namely, "D") provides a relief or an escape space for the deformed portion of the valve 15. Accordingly, the inner diameter "D" is larger than the inner diameter "d" by twice the compressed thickness of the deformed portion of the valve 15. As for the valve 15, one shown in US-A- 4,610,665, such as shown in Figs. 5 and 6 can be employed. Namely, a valve formed of a resilient disc having a pair of linear cuts, i.e. a first cut 15a opening only to the top surface of the disc, and a second cut 15b opening only to the back surface of the disc, and crossed with each other at their centers can be employed. Of course, it is possible to employ any other type of film-like valve. The valve 15 is so constructed that when the inner needle 13 is withdrawn from the outer needle hub 12 as shown in Fig. 4, the valve 15 is spontaneously closed so as to prevent body liquid such as blood from leaking out of the outer needle 10. It is desirable to make the inner wall of the proximal end portion 12b of the outer needle hub 12 into a luer tapered surface expanding toward the proximal end side of the outer needle hub 12 in view of increasing the fitting strength between the outer needle hub 12 and a connector as explained hereinafter. Next, the operation of the needle assembly as constructed above will be explained below. First, as shown in Fig. 3, the inner needle 13 is inserted into the outer needle 10 through the outer needle hub 12. When the inner needle hub 14 is sufficiently engaged to fit in the proximal end portion 12b of the outer needle hub 12, the tip portion 13a of the inner needle 13 is projected out of the tip portion of the outer needle 10, thereby rendering the needle assembly ready for smoothly piercing and penetrating into a blood vessel. Thereafter, the needle assembly is operated so that the tip portion of the outer needle 10 pierces and penetrates into, for example, a blood vessel. Subsequently, the inner needle 13 is withdrawn from the outer needle hub 12. At this moment, the valve 15 is spontaneously closed so as to prevent blood from leaking out of the outer needle hub 12. Then, a connector 16 of a blood or liquid infusion set (not shown) is fitted in the outer needle hub 12 as shown in Fig. 7 in such a manner that distal end portion of the connector 16 is inserted through the valve 15. When the distal end portion of the connector 16 is inserted through the valve 15, the valve 15 is deformed as shown in Fig. 7, i.e. the deformed portion of the valve 15 is received under compression into the enlarged portion, having a diameter of "D", of the distal portion 12a of the hub 12. Therefore, the central outer wall portion of the connector 16 is hermetically contacted to the inner wall surface of proximal end portion 12b of the hub 12, thereby allowing the connector 16 to be strongly fitted in the proximal end portion 12b. In this case, if the inner surface of the proximal end portion 12b of the hub 12 is of a luer tapered form, the fitting of the proximal end portion 12b to the connector 16 can be further improved. This in turn improves the liquid-tightness of the connection between the hub 12 and the connector 16. As explained above, the outer needle hub of the present invention is constructed in such a manner that the inner diameter of a portion of the outer needle hub which is located near the valve-mounting portion and at the outer needle side as viewed from the valve-mounting portion is enlarged by twice the compressed thickness of the deformed portion of the valve as compared with the inner diameter of a portion of the outer needle hub which is located near the valve-mounting portion and at the proximal end side as viewed from the valve-mounting portion. Therefore, even if a rod-like member such as a connector of an infusion set as described above or a tubular member is inserted through the valve, the deformed portion of the valve can be conveniently received under compression into this enlarged portion, thereby allowing the rod-like member or the tubular member to be closely contacted and secured to the inner surface of the proximal end of the outer needle hub. As a result, the fitting strength of the outer needle hub to a rod-like member or a tubular member can be increased, so that once the rod-like member or the tubular member is fitted in the outer needle hub, it would be difficult for the rod-like member or the tubular member to be detached from the outer needle hub by accident, and leakage of body liquid from the outer needle member can be prevented without fail.

Claims: A combination of a needle assembly and a rod-like member or tubular member, said needle assembly being equipped with a valve (15), and comprising an outer needle member including an outer needle (10), an outer needle hub (12) fixed to the proximal end of the outer needle (10) and having an inner passage (11) communicating with the outer needle (10), and a valve (15) mounted to close the inner passage (11) of the outer needle hub (12) and being capable of allowing said rod-like member or tubular member to pass therethrough, the outer needle hub including an enlarged hollow portion formed in a portion thereof which is located inner side of the valve-mounting portion, and said rod-like member or tubular member having an outer diameter which is substantially the same as an inner diameter of a passage of a portion of the outer needle hub (12) which is located outer side of the valve mounting portion, characterized in that the inner diameter of the enlarged hollow portion is larger by twice a compressed thickness of a deformed portion of the valve (15) as it is pressed by the attachement of the rod-like member or the tubular member than the inner diameter of said portion of the outer needle hub (12) which is located outer side of the valve-mounting portion and in which the rod-like member or the tubular member is fitted, the enlarged hollow portion forming a relief for receiving said deformed portion of the valve (15) under compression when the rod-like member (16) or the tubular member is inserted through the valve (15). The combination according to claim 1, characterized in that said portion of the outer needle hub (12) which is located outer side of the valve-mounting portion has a tapered inner wall surface. The combination according to claim 1, characterized in that said outer needle hub (12) comprises a distal portion (12a) and a proximal portion (12b), connected to each other, and the valve (15) is held between these connected portions of the distal portion (12a) and the proximal portion (12b) by the circumferential portion thereof. The combination according to claim 1, characterized in that said valve (15) is formed of a disc having a pair of linear cuts (15a, 15b), i.e. a first cut (15a) opening only to the top surface of the disc, and a second cut (15b) opening only to the back surface of the disc, and crossed with each other at their centers. The combination according to claim 1, characterized in that said rod-like member (16) is of a cylindrical form.

Inventors: DEGUCHI HIROMI, YAMAMOTO MASANOBU, DEGUCHI, HIROMI, YAMAMOTO, MASANOBU
Applicants: TERUMO CORP, TERUMO KABUSHIKI KAISHA
Application year: 1990
Main classification: A61M25
IPC codes: A61M39, A61B17