IL112814A

IL112814A - Cannula-needle assembly preventing blood backflash

Info

Publication number: IL112814A
Application number: IL112814A
Authority: IL
Original assignee: Travenol Lab Israel Ltd
Priority date: 1995-02-27
Filing date: 1995-02-27
Publication date: 1998-02-22
Also published as: WO1996026753A1; EP0957948A1; AU5174496A; IL112814A0; EP0957948A4

Description

CANNULA-NEEDLE ASSEMBLY PREVENTING BLOOD BACKFLASH τπ 7.7 mini* nna yi.nn unm inn 7i7Dn TRAVENOL LABORATORIES (ISRAEL) n"y:i (7KTW) 7U'nu miayn C: 19500 CA ULA- EEDLE ASSEMBLY PREVENTING BLOOD BACKFLASH The present invention relates to cannula-needle assemblies, and particularly to such an assembly for preventing or reducing blood backflash.

Cannula-needle assemblies are widely used for administering a liquid to a subject and/or for receiving blood samples from a subject. Such assemblies typically include a cannula insertable into a vein through an opening in the subject's skin, and a needle movable through the cannula for piercing the subject's skin to produce the opening for the cannula. The needle is then removed to enable an external device, e.g., an IV (intravenous) infusion bag, to be coupled to the cannula for administering liquid to the subject, and/or for receiving blood from the subject. Such assemblies are commonly used where intravenous infusion is to be administered to the subject, and/or where a plurality of blood samples are to be taken from the subject. Once the cannula has been inserted, it is retained in place in the subject during the complete course of the treatment, thereby avoiding the need to pierce the subject's skin each time medication is to be administered or a blood sample is to be taken.

The withdrawal of the needle from the assembly at the time of the attachment of the external device administering the medication or. receiving the blood sample, or at the time of the detachment of the external device, is frequently accompanied by a flow of blood, sometimes called blood backflash, externally of the assembly. This is not only unsightly particularly to the subject, but also exposes the health attendant or others to infection by a blood-borne disease, such as AIDS or hepatitis. A number of arrangements are described, for example in US Patents 3,977,400, 4,243,034, 4,245,635, 4,540,411, 5,098,394 and 5,167,635, for reducing or preventing blood backflash, but the known arrangements are generally of relatively complicated construction and/or inconvenient to use.

An object of the present invention is to provide a cannula-needle assembly for reducing or preventing blood backflash having advantages in the above respects.

According to the present invention, there is provided a cannula-needle assembly, comprising: a body member formed with a longitudinal passageway therethrough having a proximal end for coupling to an external device for administering a liquid to a subject, or for receiving blood from the subject, via the distal end of the longitudinal passageway; a cannula having a proximal end fixed to the body member at, and in communication with, the distal end of the passageway, the cannula having a distal end insertable through an opening in the subject's skin; a needle insertable via the proximal end of the longitudinal passageway to pass through the passageway and through the cannula, to project through the distal end of the cannula for producing the opening in the subject's skin to receive the distal end of the cannula, and then to be removed via the proximal end of the passageway before the external device is coupled thereto; an injection port formed in the body member and including a transverse passageway joined at a juncture with the longitudinal passageway for injecting a substance to be administered to the subject via the cannula; and a deformable sleeve lining the longitudinal passageway at the juncture and deformable, upon the injection of a substance via the injection port, to permit the substance to pass between the outer surface of the sleeve and the inner surface of the body member along the distal end of the longitudinal passageway to the cannula; characterized in that the assembly includes a cap receivable over the injection port for closing it; the cap being movable from an outer position to an inner position with respect to the injection port, the cap carrying a stem received in the transverse passageway and of a length such that in the inner position of the cap, the stem radially deforms the sleeve to pinch it closed and thereby to block communication between the distal and proximal ends of the longitudinal passageway .

As will be described more particularly below, such an assembly can be constructed of a few, relatively simple parts, and can be used in a very convenient manner to administer a liquid to a subject, and/or to receive a blood sample from the subject, with a minimal of blood backflash.

Further features and advantages of the invention will be apparent from the description below.

The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein : Fig. 1 is a top plan view illustrating an existing form of injection-site device particularly useful in the cannula-needle assembly in accordance with the present invention; Fig. 2 is an enlarged three-dimensional view of the assembly of Fig. 1 but incorporating a cap constructed in accordance with the present invention, with the cap shown in its inner closed position, parts being broken away to show internal structure; Fig. 3 is a transverse sectional view of the assembly of Fig. 2; Figs. 4 and 5 are longitudinal sectional views of a variation in the assembly of Figs. 2 and 3 with the cover removed, illustrating the outer-open position and the inner-closed position of the cap, respectively; Figs. 6 and 7 are top plan views of the assembly of Figs. 4 and 5 showing the cap in its released position and locked position, respectively; Figs. 8 and 9 are side and bottom views, respectively, of the cap of Figs. 4-7; Fig. 0 is a longitudinal sectional view illustrating a variation in the cannula-needle assembly of the present invention; Fig . 11 is a top plan view of the assembly of Fig. 10; and Figs . 12 and 13 are longitudinal sectional views illustrating two further variations in the cannula-needle assemblies constructed in accordance with the present invention.

The cannula-needle assembly illustrated in the drawings is shown, for purposes of example, as embodied in a conventional injection-site device, shown in Fig. 1, to be attached to a subject and to be used for administering a medication to the subject continuously or at different times, or for extracting from the subject a plurality of blood samples. The assembly is initially applied to the subject by piercing the subject's vein by means of the needle of the injection-site device, and then attaching the assembly to the subject. Once the assembly is so applied, it may be used thereafter for administering medication or for removing blood samples without the need to pierce the subject's vein each time.

The injection-site device illustrated in Fig. 1 comprises a body member, generally designated 2, formed with a longitudinal passageway 3 extending through the body member. Passageway 3 includes a proximal end 3a (Figs. 4, 5) for coupling to an external device (not shown), such as an IV bag for administering a liquid to the subject, or a syringe for receiving blood from the subject, via the distal end 3b of passageway 3. A cannula 4 is fixed at its proximal end 4a to the body member 2 at, and in communication with, the distal end 3b of passageway 3 through the body member. Cannula 4 has a distal end 4b which is insertable through an opening in the subject's vein formed by a needle 5.

The needle 5 is insertable through passageway 3, through cannula 4, and through the distal end 4b of the cannula in order to pierce the subject's vein for inserting cannula end 4b therethrough. The needle is then removed from passageway 3, and the external device is immediately attached to the body member via Luer locking elements 2a (Fig. 2) for administering medication to the subject (e.g., via an IV bag), or for extracting blood samples from the subject. The body member may then be secured to the subject's body by applying pressure-sensitive tape across the opposed tabs 2b or sutures through the openings formed in the tube.

Body member 2 further includes an injection port 6 formed with a transverse passageway 7 joined at a juncture 7a with the longitudinal passageway 3. Injection port 6 is used for administering a substance, such as another medication, to the subject after the cannula 4 has been inserted into the subject's vein. For this purpose, a deformable sleeve 8, made of an elastomeric material such as silicone rubber, is received within the longitudinal passageway 3. Sleeve 8 lines passageway 3 and also seals the juncture 7a between that passageway and the transverse passageway 7. Upon the injection of a substance (e.g., a medication) via injection port 6, sleeve 8 deforms under the injection pressure, and permits the injected substance to pass between the outer surface of the sleeve and the inner surface of the body member along the distal end 3b of passageway 3 to and through cannula 4 into the subject's vein.

The illustrated injection-site device further includes a cover 9 removably attachable over the open end of injection port 6 to close the injection port except when a substance is to be injected through that port. Cover 9 is attached to injection port 6 by means of a mounting ring 10 received around the injection port, and a pair of arms 11 integrally formed with the cover and the ring. Arms 11 thus serve as an integral hinge permitting the cover to be moved to either an open position (shown in Fig. 2), or to a closed position covering the injection port (shown in Fig. 1). A strip 12 integrally formed between the two arms 11 , and joining the cover 9 of the mounting ring 10 , serves as an over-center spring urging the cover to its open or closed positions.

The injection-site device insofar as described above, is well known and in wide use. As pointed out, however, when the needle 5 is withdrawn from the body member 2 to permit attachment of the external device (via Luer locking elements 2a) to administer a medication or to receive a blood sample, a flow of blood (backflash) results before the external device can be attached.

To prevent such blood flow, the illustrated assembly includes a cap, generally designated 20, receivable over the injection port 6. Cap 20 is formed with a stem 21 which is received in the transverse passageway 7 of the injection port and is engageable with the elastomeric sleeve 8 in the longitudinal passageway 3 to deform the sleeve and to pinch it closed, and thereby to prevent such blood backflash when the needle 5 is withdrawn.

As shown in the variation of Figs. 4 and 5 (to be described more particularly below) , cap 20 is normally in an outer position wherein its stem 21 lightly engages, or is slightly spaced from, the elastomeric sleeve 8, thereby permitting the sleeve to assume its normal tubular shape providing a flowpath to or from the cannula 4. Cap 20, however, may be manually depressed to its inner position (shown in Figs. 2, 3 and 5) wherein its stem 21 pinches-closed sleeve 8, to thereby block communication therethrough to or from the cannula.

Figs. 2 and 3 illustrate stem 21 as formed with a plurality of axially-extending, circumferentially-spaced ribs 22 for guiding the movements of the cap. Stem 21 is further integrally formed with a flexible annular skirt 23 engageable with the juncture 7a between passageways 7 and 3 in the lower position of the stem (as shown in Figs. 3 and 5) to thereby seal the injection port 6 from passageway 3 when the cap is in its inner position.

When the cap has been manually depressed to its inner position, it may be retained in this position, thereby freeing the attendant from having to maintain pressure on the cap. For this purpose, cap 20 is formed with a hook-shaped retainer element 24. After the cap has been depressed to its inner position and slightly rotated, element 24 is brought to underlie one of the arms 11 of cover 9, to thereby retain the cap in its inner position.

Cap 20 is further formed with a retainer rod 25 (Fig. 2) to extend outwardly of ring 10 mounting the cover 9 to the injection port 6. Retainer rod 25 terminates in a hook 26 engageable with the underside of mounting ring 10 in order to releasably retain the cap in its outer position, and thereby to prevent separation of the cap from the injection port. Retainer rod 25, however, is sufficiently flexible so that the user may apply a lateral force to separate hook 26 from the mounting ring 10 when it is intentionally desired to remove the cap from the injection port.

The manner of using the illustrated assembly will be apparent from the above description. Thus, needle 5 is passed through passageway 3 in body member 2, and through the cannula 4, to cause the needle and cannula to pierce the subject's vein. The needle is then withdrawn, and cap 20 is pressed inwardly (downwardly) to cause its stem 21 to pinch-close the elastomeric sleeve 8, and thereby to prevent blood blackflash. The cap is retained in its inner position by slightly rotating it to bring its hook-shaped element 24 to underlie one of the arms 11 of the cover 9. The assembly may then be attached to the subject's body by applying pressure-sensitive tapes to the opposed tabs 2b or sutures through the openings in the tabs.

In this inner position of the cap, the sealing skirt 23 integrally formed with the stem 21 engages the inner surface of juncture 7a, thereby preventing blood flow through the injection port 6, while the pinched-closed condition of sleeve 8 prevents blood flow through the sleeve.

Whenever it is desired to administer a substance to the subject, or to extract a blood sample from the subject, the appropriate external device (e.g., IV bag or syringe, respectively) may be attached to the proximal end of the body member 2 by means of the Luer male locking elements 2a. When the substance is to be administered, or the blood sample is to be taken, cap 20 is rotated slightly to cause its retainer element 24 to release from the underside of the cover arm 11. This permits the cap to move towards its outer position, and the sleeve 8 to return to its normal tubular configuration, opening the flowpath through the sleeve to or from the cannula 4. After the external device has been connected to the assembly, cap 20 may be manually removed from injection port 6, and cover 9 may then be pivotted to close the injection port.

Whenever it is desired to inject a substance via injection port, this may be done by pivotting cover 9 to its open position and injecting the substance via the injection port, whereupon sleeve 8 deforms sufficiently to permit the injected substance to pass between its outer surface and the inner surface of body member .2 to cannula 4.

Figs. 4-9 illustrate a variation in the construction of the cap 20. In this variation, the movements of the cap and its stem to their inner and outer positions are guided by a pair of external spacer elements 22' engageable with the outer surface of the injection port 6, rather than by inner guiding ribs 22 engageable with the inner surface of bore 7.

Figs. 10 and 11 illustrate an assembly similar to that described above, but with several changes. In the assembly illustrated in Figs. 10 and 11, the cap, generally designated 40, also includes a stem 41 for pinch-closing the elastomeric sleeve 8 in the inner position of the cap and stem. In this construction, however, the movements of the cap and stem are guided by an annular skirt 42 engageable with the outer surface of the injection port 6. In addition, the distal end of the body member 2 is formed with a plurality of axially-extending, circumferentially-spaced ribs 43 engageable with the distal end of sleeve 8 to assure a flowpath for any substance injected via injection port 6. Further, a retainer ring 44 is inserted into passageway 3 of body member 2, engageable with the opposite (proximal) end of sleeve 8 to prevent axial movement of the sleeve when it is pinch-closed by stem 41 of cap 40. A further modification illustrated in Figs. 10 and 11 is that the cap 40 is joined to one of the tabs 2b of the body member 2 by a strip 2c integrally formed with the cap and tab to prevent accidental loss of the cap when not received in the injection port 6.

Fig. 12 illustrates a further modification, wherein the cap 50, when in its inner position, seals passageway 7 from passageway 3 by means of an annular rib 52 integrally formed with its stem 51 and engageable with the inner surface of the juncture 7a between these two passageways in the body member.

Fig. 13 illustrates a further modification, wherein the stem 61 of the cap 60 is formed with a sealing ring 62, corresponding to sealing ring 52 in Fig. 12. Stem 61 , however, is also formed with a wedging surface 63 engageable with a corresponding wedging surface at the juncture 7a between the two passageways 7 and 3, to enhance the seal and to releasably retain the cap and its stem in their inner pinch-closing positions with respect to the elastomeric sleeve 8.

While the invention has been described with respect to several preferred embodiments, it will be appreciated that these are set forth merely for purposes of example, and that many other variations, modifications and applications of the invention may be made.

Claims

1. A cannula-needle assembly, comprising: a body member formed with a longitudinal passageway therethrough having a proximal end for coupling to an external device for administering a liquid to a subject, or for receiving blood from the subject, via the distal end of the longitudinal passageway; a cannula having a proximal end fixed to the body member at, and in communication with, said distal end of the passageway, said cannula having a distal end insertable through an opening in the subject's skin; a needle insertable via the proximal end of the longitudinal passageway to pass through said passageway and through said cannula, to project through the distal end of the cannula for producing the opening in the subject's skin to receive the distal end of the cannula, and then to be removed via said proximal end of the passageway before the external device is coupled thereto; an injection port formed in said body member and including a transverse passageway joined at a juncture with said longitudinal passageway for injecting a substance to be administered to the subject via said cannula; and a deformable sleeve lining said longitudinal passageway at said juncture and deformable, upon the injection of a substance via the injection port, to permit the substance to pass between the outer surface of the sleeve and the inner surface of the body member along the distal end of said longitudinal passageway to said cannula; characterized in that said assembly further includes a cap receivable over the injection port for closing it; said cap being movable from an outer position to an inner position with respect to said injection port; said cap carrying a stem received in said transverse passageway and of a length such that in the inner position of the cap, the stem radially deforms the sleeve to pinch it closed and thereby to block communication between the distal and proximal ends of the longitudinal passageway .

2. The assembly according to Claim 1 , wherein said cap further includes guiding means for guiding said movements of the cap and of the stem with respect to said transverse passageway.

3. The assembly according to Claim 2, wherein said guiding means comprises a plurality of ribs formed on said stem coaxial therewith and circumferentially spaced from each other engageable with the inner surface of said injection port defining said transverse passageway.

4. The assembly according to Claim 2, wherein said guiding means comprises a plurality of ribs formed on said cap and engageable with the outer surface of said injection port, said plurality of ribs being coaxial with said stem and circumferentially spaced from each other.

5. The assembly according to Claim 2, wherein said guiding means comprises a skirt formed on said cap engageable with the outer surface of said injection port during said movements of the cap with respect to said injection port.

6. The assembly according to any one of Claims 1-5, wherein said stem includes a seal engageable with the inner surface of said injection port at said juncture with said longitudinal passageway.

7. The assembly according to Claim 6, wherein said seal comprises a flexible skirt integrally formed with the stem and engageable with an inner surface of said injection port at said juncture.

8. The assembly according to Claim 6, wherein said seal comprises an annular rib integrally formed with the stem and engageable with an inner surface of said injection port at said juncture.

9. The assembly according to any one of Claims 1-8, further including retainer means for releasably retaining the cap in said inner position with respect to said injection port.

10. The assembly according to Claim 9, wherein said retainer means comprises a hook carried by said cap engageable with an element carried by the body member when the cap is in said inner position with respect to said injection port and is slightly rotated about the axis of said stem.

11. The assembly according to Claim 10 , wherein said body member comprises a cover secured to the body member by an integral hinge permitting the cover to be applied over and to close the injection port when said cap is not applied thereto, said integral hinge constituting the element carried by the body member engageable by said hook carried by said cap.

12. The assembly according to Claim 11 , wherein said cap further includes a retainer rod terminating in a hook engageable with an element carried by said body member when the cap is in said outer position to releasably retain the cap in said outer position.

13. The assembly according to Claim 12, wherein said cover and integral hinge are secured to the body member by a ring applied around said injection port, said ring constituting the element carried by the body member engageable by said hook of said retainer rod.

14. The assembly according to Claim 9, wherein said retainer means comprises a wedging surface on said stem engageable with a wedging surface on the body member at said juncture of the transverse passageway with the longitudinal passageway when the cap is in said inner position.

15. The assembly according to any one of Claims 1-14, wherein said longitudinal passageway includes a retainer ring engageable with one end of the sleeve to prevent the axial displacement of the sleeve when it is radially deformed by said stem.

16. The assembly according to any one of Claims 1-15, wherein said body member is formed at said distal end of the longitudinal passageway with axially-extending spacer ribs engageable with the respective end of the sleeve to provide a flowpath for the substance injected through said injection port.

17. The assembly according to any one of Claims 1-16, wherein said sleeve is of elastomeric material. Rehovot 76122 C: 19500