Phlebotomy needle system incorporating means to add anticoagulant and wash liquid

Abstract

A phlebotomy needle system providing means to introduce anticoagulant into blood immediately after it is discharged from the needle cannula into a blood transfer tube and to coat the walls of the tube with a thin film of anticoagulant up until at least that point where the anticoagulant is thoroughly mixed through the blood. Means are also provided within the same system for backflowing a wash solution into the needle.

Description

This invention relates to phlebotomy needles and particularly to phlebotomy needles systems used in pheresis procedures wherein more than one unit of blood may be conducted through the needle.

In the pheresis procedure, blood is withdrawn from a donor, the desired blood component (usually platelets) is separated out from the blood, and the blood essentially free of the desired component is returned directly to the donor. This procedure normally permits the donor to donate many units of certain blood components during the time normally required for regeneration of one unit of whole blood. Since, however, a greater quantity of blood must flow in both directions through the pheresis needle and its associated tubulations, the possibilities of the blood's clotting within the needle and tubulations increases. Measures must therefore be taken to prevent such clotting.

The needle systems presently used in the pheresis procedure are hooked up with an array of fitments and tubulations such that there are various discontinuities on the walls of the internal blood passage between the point of the cannula of the needle and the junction of the passage with the admission point of an anticoagulant which is added to the blood. It is well known that many of the discontinuities in the surface of a passageway for whole blood which has not been treated with an anticoagulant tend to initiate a clotting reaction which, over a brief period of time, will build up a clot of sufficient size to restrict blood flow. It is common practice to introduce an anticoagulant into the blood sometime after it leaves the cannula of the needle, a practice which permits the blood to contact the tubulation surface prior to the addition of the anticoagulent. This tubulation is joined through fitments to the cannula; and such fitments and their associated tubulations (normally referred to as the "harness") of the presently used pheresis needles are permanently attached to the needle. This means that if for any reason the needle can not be used successfully, it is necessary to replace the entire harness before attempting a fresh venipunctuce. Finally, it is customary in using the presently available pheresis needles to provide separate fitments and tubulation (harness) for the admission of a saline wash solution, an arrangement which complicates the structure and use of the needle and adds to its cost.

It would therefore be desirable to have a phlebotomy needle system, and particularly a phelbotomy needle system useable for the pheresis procedure, which overcomes the disadvantages associated with the prior art types of needles systems designed for this purpose.

It is therefore a primary object of this invention to provide a phlebotomy needle system particularly suitable for pheresis procedures which essentially eliminates the possibility of clot formation in the needle, in its fitments and in tubulations attached thereto. It is an additional object of this invention to provide a phlebotomy needle system of the character described which provides for the introduction of the anticoagulant into the blood at the discharge end of the cannula and also provides for introducing the anticoagulant as a continuous film on the walls of the blood passageway so that the blood encounters anticoagulant before it encounters any wall of the passageway beyond the discharge end of the cannula.

It is another object of this invention to provide a phlebotomy needle and harness which permits the disengagement of the needle from the harness and replacement by another needle while maintaining aseptic conditions.

Still another primary object of this invention is to provide a phlebotomy needle system with such fitments and tubulation which incorporate directly therein means to introduce a saline wash solution through said needle when blood is not being carried through the needle.

Other objects of the invention will in part be obvious and will in part be apparent hereinafter.

In the phlebotomy needle system of this invention, the cannula is fitted at the discharge end with a tapered hub positioned to allow a short free length of the cannula to extend beyond the hub. The hub makes a removable liquid-tight friction fit with one end of a socket member which has a central chamber. A central channel and two auxiliary side channels extend through the other end of the hub into the central chamber. The central channel is sized to permit a blood-transfer tubing to be inserted therein and bonded to the socket. When the hub is fitted into the socket the free length of the cannula extends into the central tubulation and defines with it an annular fluid passage in fluid communication with the central chamber in the socket. The two auxiliary side channels have tubings inserted in them and these tubings are in turn bonded to the socket member. When an anticoagulant is introduced through the tubing in one of the auxiliary channels it is caused to flow through the annular fluid passage to be mixed with the blood immediately as it is discharged from the cannula and to form a film along the inner wall of the blood-transfer tubing. Thus no blood without anticoagulant contacts the tubulation surface. In a similar manner, when blood flow through the needle is stopped, a saline wash solution may be introduced through the tubing in the other of the auxiliary channels to flow through the annular fluid passage and enter the discharge end of the cannula.

The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts which will be exemplified in the construction hereinafter set forth, and the scope of the invention will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings in which

FIG. 1 is a general view of the needle system of this invention showing the auxiliary tubings attached to a source of an anticoagulant and a source of a saline wash solution;

FIG. 2 is a side elevational view of one embodiment of a needle of the needle system of this invention illustrating the use of a stainless steel cannula;

FIG. 3 is a cross section of the needle of FIG. 2 taken through plane 3--3 of FIG. 2;

FIG. 4 is a cross section of another embodiment of a needle of the needle system of this invention illustrating the use of a flexible cannula having a rigid lancet;

FIG. 5 is a longitudinal cross section of the socket member of this invention showing the hub of the needle in fully engaged position;

FIG. 6 is a longitudinal cross section of the socket member of FIG. 5 taken through plane 6--6 of FIG. 4;

FIG. 7 is a top plan view of the socket member without tubulations; and

FIG. 8 is a cross section of the socket member of FIG. 5 taken through plane 8--8 of FIG. 5.

The phlebotomy needle of this invention is illustrated in FIG. 1 with its harness attached to a source of anticoagulant a source of saline solution and a blood reservoir in the form of a centrifuge rotor. The needle 10 is comprised of a cannula 11, a hub 12 and a gripping member 13 affixed to the hub. In FIG. 1 the needle is shown to be partially withdrawn from its aseptic cover 14 which is not part of this invention. Hub 12 is engaged with a socket member 16 to which the blood-transfer tubing 17, the anticoagulant tubing 18 and saline solution tubing 19 are affixed. Hub 16 and tubings 17, 18 and 19 make up the harness generally indicated at 20. Anticoagulant tubing 18 is shown to be connected to an anticoagulant source 21, and saline solution tubing to a saline solution source 22. Pinch clamps 23 and 24 are provided to control the flow of the anticoagulant and saline solution, respectively. In the system of FIG. 1, the liquids are gravity fed. It is, of course, within the scope of this invention to use any other means to cause the anticoagulant and the saline solutions to flow in their respective tubings and to use means other than pinch clamps to control their flow. The actual means by which these liquids are introduced into and pumped through the tubulations is not part of this invention. The blood transfer tubing is shown to be connected to a reservoir 25, such as a centrifuge rotor of a system similar to that shown in U.S. Pat. No. 3,145,713.

Two embodiments of needles suitable for use in the needle system of this invention are shown in side elevational and cross sectional views in FIGS. 2-4. In these FIGURES, as well as in all of the other of the FIGURES, the same reference numerals are used to identify the same elements of the apparatus.

In the needle embodiment of FIGS. 2 and 3 the cannula 11 is of the well-known rigid, stainless steel type; while in FIG. 4 it is formed as a flexible tubing 25 having a bevelled end 26. Such tubing is generally made from a polytetrafluoroethylene resin. Since cannula 25 is flexible, it is necessary to give it the necessary degree of rigidity for venipuncture and this is done by inserting a solid stainless steel lancet 27 throughout the entire length of the flexible tubing 25. The end 28 of the lancet which extends just beyond the inlet end of cannula 25 is configured to gain ready access to the interior of the vein and provide for the insertion of flexible cannula 25 into the vein, and the end 29 of the lancet which extends beyond the discharge end of cannula 25 is bonded to a needle cap 32 which is configured to fit over hub 12. Subsequent to making the venipuncture, cap 32 is removed while pressure is supplied to the vein, thus withdrawing the lancet and opening the passage in flexible cannula 25. The term "cannula" is therefore hereinafter used in its broadest sense to designate either a rigid or flexible tubing member. In FIGS. 5-8, the cannula 11 of FIGS. 2 and 3 is shown as an exemplary cannula.

In either needle embodiment of FIGS. 3 or 4, the hub 12, typically formed of a haemocompatible molded plastic such as polycarbonate, is fitted onto the discharge end of the cannula and bonded thereto by ultrasonic insertion or by a suitable adhesive. Hub 12 has a tapered section 30, the diameter decreasing toward the discharge end of cannula 11, and a straight section 31. The gripping member 13 (or 13a in FIG. 4) is attached to straight section 31. A short length of cannula 11 or 25 extends beyond the tapered section 30 of the hub. As is known in the art, gripping member 13 or 13a is of a flat configuration designed to give the doctor or nurse performing the venipuncture a firm grip on the needle and a means for sensing needle orientation.

The socket member 16, through which the needle is removably attached to the harness, is shown in several views in FIGS. 5 - 8. This socket like the hub 12 is molded of a suitable haemocompatible synthetic resin material such as a polycarbonate. Socket 16 is formed to have a needle-engaging section 35, shown in the drawings to have an external taper with the diameter increasing toward the discharge end of cannula 11, and a tubulation-engaging section 36 of a generally elliptical configuration as seen in FIGS. 7 and 8. This external taper in the needle-engaging section 35 is not essential. Needle-engaging section 35 has a hub-engaging passage 37 having a tapered configuration, the diameter of the internal walls of the passage decreasing toward the internal opening 38 which terminates in central chamber 39 within the socket member. The degree of taper of passage 37 corresponds to that of hub section 30 so that when the needle is affixed to the socket, the surface of hub section 30 makes a liquid-tight friction fit with the wall of hub-engaging passage 37 of the socket member.

Tubulation section 36 of the socket member (shown in top plan view of FIG. 7 and in cross-section in FIG. 8) is configured to accept and hold blood-transfer tubing 17 axially aligned with cannula 11 and the two auxiliary tubings 18 and 19 for anticoagulant and saline solution on either side. A central channel 40 defined by wall 41, which terminates internally in the socket in a lip 42, serves to receive and hold blood-transfer tubing 17. This tubing is seated on lip 42 and is bonded to the socket member such as by solvent bonding around entrance 43 of channel 40. The location of the lip seat 42 should be such as to position blood-transfer tubing 17 so that the free end of cannula 11 extends into it to define an annular liquid passageway 44.

Similarly, the socket member has a wall 45, merging into one side of wall 41, to define channel 46 terminating in a lip 47 to receive and seat anticoagulant tubing 18 which is bonded at 48 to the socket. Liquid communication between tubing 18 and central chamber 39 is by way of channel 49. In like manner, the socket member has a wall 50, merging into the other side of wall 41, to define channel 51 terminating in a lip 52 to receive and seat saline solution tubing 19 which is bonded at 53 to the socket. Liquid communication between tubing 19 and central chamber 39 is by way of channel 54.

In some applications of a needle system such as the one of this invention, it may not be necessary to backwash the needle with saline solution. Therefore it is within the scope of this invention to eliminate saline solution tubulation 19, channel 51 in the socket and channel 54 within chamber 39.

Prior to making the venipuncture, the anticoagulant tubing, socket member passages, needle cannula and adjacent portions of the blood tubing are primed with anticoagulant. In operation, as soon as blood begins to flow in cannula 11, the flow of anticoagulant through tubing 18 is begun. It will be seen in FIG. 5 that the anticoagulant (the flow of which is indicated by the dotted arrows on only one side of passage 44) enters blood-transfer tubing 17 through annular passage 44 by way of channel 49 and central chamber 30. Thus the anticoagulant is available for mixing with the blood (the flow of which is indicated by the solid arrows) immediately upon its discharge from cannula 11. This flow pattern of the anticoagulant, which is, of course, around the entire surface of cannula 11, also provides a continuous film of anticoagulant around the entire surface of the inner wall of tubulation 17 up to at least a point where the anticoagulant is thoroughly mixed with the blood. This means that the unanticoagulated blood never comes into contact with any discontinuities in the transfer system which could give rise to clotting. Hence a free flow of blood is insured throughout the pheresis procedure.

In the case where the needle of FIG. 4 with a flexible cannula is used, the socket 16 and harness 20 are not attached to the needle until after the venipuncture is accomplished. As noted previously in the description of FIG. 4, after venipuncture is made, the needle cap 32 is removed and along with it the steel lancet. During the removal of cap 32 and engagement of the needle with the hub, pressure is applied to the punctured vein. Once this engagement is effected the pressure is removed and the anticoagulant is added to the blood as described.

When the flow of blood and anticoagulant is stopped, the flow of saline wash solution, if used, is begun through tubing 19. As indicated by the dash-dot arrows, this saline solution travels through channel 54, central chamber 39 and annular passage 44 to enter the discharge end of cannula 11, thus washing the passages free from blood which could clot. This saline solution also, of course, contacts the entire surface of the walls defining passage 44, the single arrow being used for clarity in the drawing.

If during venipuncture, the needle fails for one reason or another, if may be readily disengaged from its friction fit with the socket and replaced by another needle without the need for replacing the socket and the tubulation connections as well. By incorporating the ability to introduce the saline wash solution through the same connections within the socket member, a material saving in cost of equipment is realized. Moreover, the entire procedure is simplified and as a result is made more fail-safe.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in the above construction without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Claims

I claim:

1. In a phlebotomy needle system suitable for withdrawing blood from a donor and delivering said blood to a reservoir through a blood transfer tube, including a needle cannula and hub affixed thereto and having tubulation means for introducing an anticoagulant into said blood as it is transferred to said reservoir, the improvement comprising a socket member removably connected through a liquid-tight friction fit with said hub, said socket member comprising a central chamber into which the discharge end of said cannula extends, supporting means within said socket member by which the inlet end of said blood-transfer tube is supported in position to surround said discharge end of said cannula to define an annular passage therebetween providing communication between said central chamber and said blood transfer tube, a first auxiliary transfer tube, and means by which the discharge end of said first auxiliary transfer tube is supported in said socket member whereby said first auxiliary tube is in fluid communication with said annular passage through said central chamber.

2. A phlebotomy needle system in accordance with claim 1 including a second auxiliary transfer tube and means by which the discharge end of said second auxiliary transfer tube is supported in said socket member whereby said second auxiliary transfer tube is in fluid communication with said annular passage through said central chamber.

3. In a phlebotomy needle system including a needle cannula suitable for withdrawing blood from a donor and having tubulation means for introducing an anticoagulant into said blood as it is transferred to a reservoir, the improvement comprising

a. a tapered hub fit over the discharge end of said cannula of said needle to allow a short length of said discharge end to extend beyond said hub; and

b. a socket member affixed to said hub through a removable liquid-tight friction fit and defining therein

1. a central chamber,

2. a central channel opening into said central chamber having affixed therein a blood-transfer tube defining an internal passage and being of sufficient depth to permit a portion of said shorth length of said discharge 2. of said cannula to extend into said central channel to define with said internal passage of said blood-transfer tube an annular fluid passage, and

c. a first side channel having affixed therein a first auxiliary tubing in fluid communication through said central chamber with said annular fluid passage, whereby when an anticoagulant is introduced through said first auxiliary tubing it is mixed with said blood before it encounters any surface beyond said discharge end of said cannula.

4. A phlebotomy needle system in accordance with claim 3 including a second side channel having affixed therein a second auxiliary tubing in fluid communication through said central chamber with said annular fluid passage, whereby when a wash solution is introduced through said second auxiliary tubing in the absence of blood and anticoagulant flow it enters the discharge end of said cannula by way of said annular passage.

5. A phlebotomy needle system particularly suited for use in a pheresis procedure, comprising in combination

a. a needle comprising a cannula and a hub which includes a tapered section, and is affixed to said cannula to allow a short free length of the discharge end of said cannula to extend beyond said hub;

b. a primary tubing adapted to transfer blood and two auxiliary tubings adapted to transfer an anticoagulant and a wash solution;

c. a socket member removably engaged with said hub, having a central chamber and holding the ends of said primary and auxiliary tubings in relation to the discharge end of said cannula whereby said free length of said cannula extends through said central chamber into said primary tubing to define an annular passage providing fluid communication between said central chamber and said primary tubing and said auxiliary tubings are in fluid communication with said annular path through said central chamber.

6. A phlebotomy needle system in accordance with claim 5 wherein said socket member has seat means for positioning the ends of said tubings therein.

7. A phlebotomy needle system in accordance with claim 5 wherein said tubings are bonded to said socket member.

8. A phlebotomy needle system in accordance with claim 5 wherein said hub makes a liquid-tight, friction fit within said socket member.

9. A phlebotomy needle system in accordance with claim 5 including gripper means affixed to said hub.

10. A phlebotomy needle system in accordance with claim 5 wherein said cannula is a rigid stainless steel tubing.

11. A phlebotomy needle system in accordance with claim 5 wherein said cannula is a flexible tubing having a rigid lancet extending therethrough and beyond the inlet and outlet ends of said flexible tubing.

12. A phlebotomy needle system in accordance with claim 5 including a source of an anticoagulant connected to one of said auxiliary tubings and a saline wash solution connected to the other of said auxiliary tubings and means to control the flow of said anticoagulant and said wash solution through said tubings.

13. A phlebotomy system in accordance with claim 5 wherein said primary tubing is connected to a blood reservoir.

14. A phlebotomy system in accordance with claim 13 wherein said reservoir is a centrifuge rotor.