Fluid Collection Device

Abstract

A fluid collection device provided with a plurality of fluid sample containers to permit continuous fluid collection which comprises a cannula having a slantwise cut opening formed at both ends, a hub disposed at the middle part of the cannula so as to be connected to a holder used in the insertion of a sample container and a blind, cylindrical, self-sealing elastic sheath provided on one side of the hub so as to loosely envelop part of the cannula, whereby, when connected to the sample container, the sheath is pressed by the plug member of the sample container to have its top portion punctured by the pointed end of the needle member and in consequence collapses toward the hub and, when the sample container is drawn out of the subject device, is brought back to its original position, thereby preventing the efflux of a fluid outside of the sheath.

Parent Case Text

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of Ser. No. 208,246, filed Dec. 15, 1971, now abandoned, which was in turn a continuation-in-part of Ser. No. 56,283, filed July 20, 1970, now abandoned.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a fluid collection device capable of repeatedly collecting a fluid, for example, blood sample with a venipuncture needle inserted into the vein.

In recent years, there has come into use a vacuum blood collection device in collecting blood samples for various blood examinations. A prior art fluid collection device of such type consists of a vacuum fluid collection container, a holder used for its insertion and a venipuncture needle member fitted to the holder. Said needle member has a pointed blade formed at both ends, one of which penetrates the plug member of the vacuum fluid collection container to effect blood collection. With the conventional fluid collection apparatus, the end opening of the needle member penetrating the plug member of the vacuum fluid collection container is always left open. Accordingly, when the needle member is inserted into the vein for blood collection, the blood tends to flow into the holder under its own pressure and soil a blood collection cylindrical member before the needle member pierces the plug member of the blood collection container, leading to not only blood loss but also discomfort to patients. There occurs the further drawback that blood still remaining in the needle member after blood collection most likely drips into the holder.

While various blood examinations naturally require large amounts of blood to be collected, the aforesaid prior art fluid collection apparatus fails to collect a plurality of blood samples with the venipuncture needle inserted into the vein.

In addition to the fluid collection apparatuses described above, there are other types wherein there is fitted an elastic rubber sheath on to a needle member to eliminate the aforementioned drawbacks. Among said other types, there is one wherein the rubber sheath is tightly attached to the needle member. Such apparatus is likely to present difficulties in allowing the sheath to be brought back to its original position and also in steam sterilizing the tightly contacted portion of the needle member and sheath. There are still other types wherein the end of the needle member is fitted with a cylindrical rubber sheath whose bottom end is cut at right angles to its lengthwise direction. If, in such case, the needle member should slantwise pierce the sheath, it will penetrate the side wall of the sheath deeply, preventing the sheath from being quickly returned to its original position due to a great resistance presented by the needle.

SUMMARY OF THE INVENTION

The present invention has been accomplished in view of the aforementioned situation and is intended to provide a fluid collection apparatus which is capable of continuously collecting many fluid samples with a needle member inserted into the human body, for example, the vein and also preventing blood and other types of liquid from soiling the interior of the holder as is the case with the conventional fluid collection apparatus.

Another object of this invention is to provide a fluid collection device which enables a rubber sheath to make a substantially full return, thereby permitting quick fluid collection. Still another object of the invention is to provide a fluid collection device which facilitates the fitting of the rubber sheath to a cannula and, once fitted, prevents it from being readily loosened therefrom.

The fluid collection device of the present invention comprises a fluid collection device which comprises a holder for inserting a fluid sample container into the device, a needle member fitted to one end of the holder through a hub parallel to the longitudinal axis of the holder and having a slantwise cut opening formed at both ends, one of which projects outside of the holder to constitute the front part of the needle member for piercing the skin and the other end of which projects into the holder for connection with a fluid sample container to form the rear part of the needle member and a self-sealing elastic sheath 0.7 to 0.8 mm in thickness overall and having hemispherical top portion, said sheath being fixed to a projection comprising neck portion and frustoconically chamfered larger head portion and enveloping the whole rear part of the needle member, whereby, before the rear part of the needle member is connected to the fluid sample container, the sheath assumes a first position where it loosely envelops all the rear part of the needle member, the clearance between inner top portion of the sheath and pointed portion of the rear part of the needle member being 1 to 3 mm, and the clearance between the inner side wall of the sheath and side wall of the needle member being 0.1 to 0.5 mm and, when said rear part is connected to the fluid sample container, the sheath is pressed by the container to have its top portion punctured by the pointed end of the rear part of the needle member and collapses toward the hub to allow the end of the rear part of the needle member to communicate with the fluid sample container, thus assuming a second position at which the fluid is permitted to be conducted from the human body to the fluid sample container, and upon removal of the needle member from the fluid sample container, the sheath spontaneously regains said first position.

BRIEF EXPLANATION OF THE DRAWING

FIG. 1 is an enlarged view, partly in section, of a needle member to which a sheath is fitted;

FIG. 2 is an enlarged partial view, partly in section, of another embodiment to which a sheath is fitted; and

FIGS. 3 to 5 are sectional views showing the sequential steps of fitting a fluid sample container.

DETAILED DESCRIPTION OF THE INVENTION

There will now be described the present invention by reference to the appended drawings. FIG. 1 denotes a needle member to which there is fitted a sheath. The needle member comprises a metal cannula 11 having a slantwise cut opening formed at both ends which constitute the front and rear parts 11a and 11b respectively, and a hub 14 fixed substantially at the middle part of the cannula 11 by means of a through hole bored along the central axis of said hub and provided with a male screw 13 for engagement with the later described holder 16. The hub 14 is made of, for example, a plastics material, and to that side of the hub 14 which faces the rear part 11b of the cannula 11 is fitted through the projection 14a of the hub 14 a blind, cylindrical sheath 15 so as to envelop the whole rear part 11b of the cannula 11. As shown in FIG. 2, the projection 14a comprises a neck portion 14b and larger head portion 14c having a frustoconically chamfered end 14d. Since the head portion 14c is sufficiently tapered, for example, at an angle of about 45.degree. to effect the easy engagement of a rubber sheath 15 and has a proper outer diameter, the rubber sheath 15 will be prevented from coming off simply by being fitted on to the needle member, thereby withstanding a pulling load of, for example, 150 to over 400 g. The sheath 15 consists of, for example, an elastic rubber member which is puncturable and self-sealing and envelops the rear part 11b of cannula 11 loosely or with a slight gap allowed. The top 15a of the sheath 15 is hemispherical, with a clearance A of about 1 to 3 mm, preferably 1.5 to 2.5 mm allowed between the inner wall of said top 15a and the end of the rear part 11b of the cannula 11. Where the clearance A is reduced to below 1 mm, the sheath will be obstructed in its return due to an insufficient resilient force. Conversely where the clearance exceeds 3 mm, the needle will probably pierce the side of the sheath, preventing it from making a full return. Further, the clearance between the inner wall of the sheath 15 and the outer wall of the cannula 11b should be 0.1 to 0.5 mm. If the clearance falls to below 0.1 mm, the contact of the sheath with the cannula 11b will present so great a resistance as to obstruct the return of the sheath 15. If, otherwise, the clearance is larger than 0.5 mm, the sheath 15 will loosely engage the projection 14a, preventing the sheath from being pricked by the needle exactly at the center of the end and in consequence obstructing the return of the sheath due to its side being possibly pierced by the needle. The wall of the sheath 15 need not be made particularly thick, but should preferably be 0.7 to 0.8 mm thick. If the wall thickness is smaller than 0.7 mm, the sheath will be decreased to below 250 g in resilience, resulting in its insufficient return. Conversely, if the thickness is larger than 0.8 mm, the sheath will have a resilient force of more than 400 g, giving rise to the drawback that such great recoiling force will push back the sample container 12 pierced by the needle for fluid collection to the outside of the holder 16. A sheath of the aforementioned size is particularly adapted for use with a cannula 0.7 to 0.9 mm in diameter.

The needle member thus constructed is engaged with a cylindrical holder 16 as shown in FIG. 3. At one end of the holder 16 is projectingly formed a fitting part 17 provided with female screws. The hub 14 of the needle member registers with said female screws in such a manner that the rear part 11b of the needle member projects into the holder 16, thereby connecting the needle member to the holder 16.

Where there is used a fluid collection device arranged as described above, for example, in blood collection, there is first inserted, as shown in FIG. 3, the fluid sample container 12 into the holder 16, or alternatively, prior to the fitting of the needle member to the holder 16, the fluid sample container 12 is inserted into the holder 16 so as to allow it to approach the needle member, and then the needle member is connected to the holder 16. Under such condition, the front part 11a of the needle member is inserted into the vein of a person from whom there is to be collected blood. Though, at this time, blood comes into the rear part 11b of the needle member, said rear part 11b is enveloped by the sheath 15, so that blood is prevented from flowing outside of the sheath 15, and in consequence soiling the interior of the holder 16. Further insertion of the fluid sample container 12 into the holder 16 causes, as shown in FIG. 4, the projecting end of the sheath to contact a depression 18a formed in the plug member 18 of the fluid sample container 12. When the fluid sample container is further pushed in, the top portion of the sheath 15 is punctured, as shown in FIG. 5, by the pointed end of the rear part 11b, and then, the sheath 15 collapses toward the hub 14, allowing the rear part 11b to penetrate a self-sealing plug member 18. At this moment, the interior of the fluid sample container 12 is in an evacuated state, exerting a suction force, so that blood flows into the fluid sample container 12 through the needle member. When the fluid sample container 12 is drawn out after required amounts of blood are collected, then the sheath 15 will regain its original position, namely, so as to fully envelop the rear part 11b of the needle member as shown in FIG. 3, preventing the holder 16 from being soiled with blood after its collection is completed. Accordingly, blood collection can be repeated by connecting a fresh fluid sample container 12 to the needle member which is kept inserted into the vein throughout this period. The surface of the rear part 11b may preferably be coated with silicone oil. In this case, instant restoration of the sheath 15 will be promoted by the lubricating action of the silicone oil.

With a fluid collection device according to the present invention, the rear part of the needle member is enveloped, as mentioned above, with a puncturable, self-sealing elastic sheath, so that the rear part is not exposed during operation or at the time fluid sample containers are replaced, but is saved from contamination. Further, the fluid collection device of this invention has an elastic sheath having its end formed into a hemisphere and prepared in substantially uniform thickness with an adequate space allowed between the inner wall of the sheath and the outer wall of the cannula, thereby enabling the sheath to return quickly and reliably when released from contraction. Further, the sheath can be tightly fitted to the hub simply by engaging it with the projection formed at the end of the hub, offering very great practical advantage in fabricating and manipulating the device. According to the present invention, blood collection can be easily effected without the possiblity of the interior of the holder being soiled with blood spilled. Blood thus spilled not only goes to waste, but also sticks to an operator collecting the blood and gives psychological discomfort to the operator as well as to the patient. Further, the open section of the rear part of the needle member assumes the form cut slantwise with respect to the longitudinal axis of the cannula so that the needle member as a whole is easy to manufacture due to its simple construction, and enables streams of blood to run smoothly therethrough. It should also be noted that since the structure of the rear part of the cannula is the same as that of an ordinary type of needle, it is possible to employ a relatively fine needle, e.g. 0.7 to 0.9 mm in diameter as the cannula.

In the foregoing embodiment, there has been described blood collection for illustration of the needle member according to the present invention. It will be apparent, however, that the invention is not limited to such application but will be applicable in collecting samples of other types of fluid.

Claims

What we claim is:

1. A blood transfer device comprising a tubular container holder having an open end and a closed end, a double-ended, hollow needle fitted to the closed end of the holder through a hub parallel to the longitudinal axis of said holder and having its rear end within the interior of the holder and its front end outside the holder, a needle puncturable, self-sealing, rubber elastic sheath sealingly enveloping said rear end of the needle, a cylindrical container having a closed end and an open end in which a stopper is sealingly attached, said container extending at said open end at least part way into said holder, said needle being 0.7 to 0.9 mm in outer diameter, said elastic sheath being 0.7 to 0.8 mm in wall thickness and having a closed hemispherical end portion, the clearance between the inner surface of said hemispherical end portion of the sheath and the rear end of the needle being 1 to 3 mm, and the clearance between the inner side wall of the sheath and the opposed side wall of the needle being 0.1 to 0.5 mm and, when upon further movement of said container into the holder said rear end of the needle pierces the container stopper, the sheath is pressed by the container stopper to have said hemispherical top portion punctured by said rear end of the needle and collapsed toward said hub and to allow said rear end of the needle member to communicate with the fluid sample container, thus assuming a position at which the fluid is permitted to be conducted through the needle to the fluid sample container, and upon removal of the needle member from the fluid sample container, the sheath spontaneously regains its original position enveloping the rear end of the needle.