Multiple Sample Needle Assembly With One-way Valve And Blood Flow Indicator

Abstract

A needle assembly for facilitating the collection of a blood sample from a patient into an evacuated collection container and indicating when a venipuncture has been accomplished and preventing flow of fluid from the collection container into the patient during and after collection of the blood sample. The assembly includes a housing having a chamber therein, a forward penetrating end including a cannula extending from the housing for penetration into the blood vessel of a patient, and a rearward end including a cannula extending from the housing and adapted to be coupled in fluid communication with the interior of an evacuated collection container. Surfaces of the assembly form a passageway for directing blood from the blood vessel through the housing to the collection container when the forward end is in the blood vessel and the rearward end is in the container. A valve assembly is mounted in the chamber in the housing and normally is in the unarmed position with passages therein to permit blood to flow from the vein into the chamber upon venipuncture. The assembly is shiftable to an armed position to close the passageway from the vein into the chamber by means of a resilient elastomeric valve member in the chamber. The valve member is adapted to be responsive to a reduction in fluid pressure at the rearward end to deform and automatically open the passageway and permit blood to flow from the blood vessel to the rearward end. Thereafter, the valve member is responsive to a predetermined increase in fluid pressure at the rearward end to automatically return to the closed position to thereby prevent flow of fluid from the rear end of the assembly to the blood vessel.

Description

BACKGROUND OF THE INVENTION

In the blood sampling field, there are several well known systems. One of the more commonly used systems is the collection of blood from a vein through a needle assembly into an evacuated container. The evacuated container provides the pressure differential necessary to facilitate flow and collection of the blood through the needle assembly into the container. The basic system and apparatus for collecting blood in this manner is disclosed in U.S. Pat. No. 2,689,564 to Kleiner.

Improvements have been made in recent years to the basic evacuated container system for blood sampling such as by the provision of a valve on the assembly to automatically open and close the flow path through the assembly as evacuated containers are coupled in succession with the assembly. In this manner, a multiplicity of samples can be collected in a multiplicity of containers with only one venipuncture required. Needle assemblies with automatic valves are shown and described in U.S. Pat. No. 3,469,572 to Nehring and U.S. Pat. No. 3,494,352 to Russo et al. Frequently the evacuated containers contain chemical materials, useful in the clinical laboratory test to be conducted after mixing with the patient's blood. However, these chemical materials may be harmful to a patient if any were to flow from the evacuated container into the patient's blood system. This problem has been successfully eliminated by use of a one-way valve as shown and described in my co-pending application Ser. No. 267,559 filed on June 29, 1972

In systems such as those referred to above, it has often been found that it is desirable to provide an indication means on the needle assembly to inform the operator when he has successfully accomplished a venipuncture. Once a venipuncture has been accomplished and indicated the indication means would no longer be necessary and could be dispensed with during further operation of the needle assembly in collection of one or more samples of blood without danger of back flow. Consequently, it would be extremely advantageous to provide a single device which includes a one-way valve for use in collecting multiple samples of blood from a single venipuncture into a multiplicity of collection containers while eliminating the danger of back flow of fluid into the patient and which includes a blood flow indication means which indicates that a venipuncture has successfully been accomplished to the operator so that the evacuated collection container can be fully coupled into fluid communication with the needle assembly.

SUMMARY OF THE INVENTION

With the above background in mind, it is among the primary objectives of the present invention to provide a multiple sample collection needle assembly whereby a multiplicity of samples can be obtained from a single venipuncture into a multiplicity of collection containers with the needle assembly including a one-way automatic valve which is responsive to a pressure differential to permit blood to flow into the collection container and which is automatically responsive to a predetermined pressure change to automatically prevent back flow of fluid into the patient. A needle assembly is also designed to include a blood flow indicator to inform the operator when a venipuncture has been successful so that a collection container can be fully coupled with the needle assembly to provide fluid communication between the patient and the collection container. The assembly is designed so that the venipuncture indicator is deactivated upon accomplishment of a successful venipuncture and thereafter leakage is prohibited from the assembly between collections of separate samples in successive collection containers.

To accomplish the above objectives, a needle assembly is provided which includes a housing having a chamber therein, a forward penetrating end including a cannula extending from the housing for penetration into the blood vessel of a patient, and a rearward end including a cannula extending from the housing and adapted to be coupled in fluid communication with the interior of an evacuated collection container. There are surfaces of the assembly which form a passageway for directing blood from the blood vessel through the housing to the collection container when the forward end is in the blood vessel and the rearward end is in the container. A valve assembly is mounted in the chamber in the housing and normally is in the unarmed position with passages therein to permit blood to flow from the vein into the chamber upon venipuncture. The assembly is shiftable to an armed position to close the passageway from the vein into the chamber by means of a resilient elastomeric valve member in the chamber. The valve member is adapted to be responsive to a reduction in fluid pressure at the rearward end to deform and automatically open the passageway and permit blood to flow from the blood vessel to the rearward end. Thereafter, the valve member is responsive to a predetermined increase in fluid pressure at the rearward end to automatically return to the closed position to thereby prevent flow of fluid from the rear end of the assembly to the blood vessel.

With the above objectives, among others, in mind, reference is had to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a side elevation view of the needle assembly of the invention shown in engagement with a holder and with an evacuated container in position for coupling therewith;

FIG. 2 is an enlarged fragmentary section view thereof subsequent to an indicated venipuncture and prior to initial closure of the valve member;

FIG. 3 is an enlarged sectional view of the needle assembly of FIG. 2 shown in the same operable position;

FIG. 4 is a sectional elevation view thereof subsequent to shifting of the valve member to the closed position after indication of a venipuncture and prior to completion of coupling in fluid communication with an evacuated collection container;

FIG. 5 is an enlarged sectional view of the needle assembly of FIG. 4;

FIG. 6 is a fragmentary sectional elevation view thereof with an evacuated collection container in full coupled fluid communication with the needle assembly and the valve member in the opened position to permit blood to flow between the vein and the collection container;

FIG. 7 is an enlarged sectional elevation view of the needle assembly as shown in FIG. 6;

FIG. 8 is a fragmentary sectional elevation view thereof with the collection container having been removed and the valve member in the closed position preventing flow between the ends of the needle assembly;

FIG. 9 is a fragmentary enlarged elevation view of the needle assembly as shown in FIG. 8; and

FIG. 10 is an exploded fragmentary perspective view of the needle assembly of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The separated components of the needle assembly 20 are shown in FIG. 10. The assembly includes a housing 21 which is in two parts, a forward part 22 and a rear part 23. Mounted in the forward part 22 is a cannula 24 and mounted in the rear part 23 is a second cannula 25. When forward end 22 is engaged with rear end portion 23 an interior chamber 26 is formed as shown in FIGS. 1-9. Housed in chamber 26 is an elastomeric sleeve 27, a rigid cage 28, a retaining disc 29, and an elastomeric sealing disc 30.

Forward end portion 22 has a tapered cylindrical outer rear surface 31 which frictionally engages with an inner cylindrical surface 32 on rear end 23. The frictional interengagement is rigid enough to prevent disassembly of the parts of housing 21 during operation of the assembly. If desired, to insure the interengagement of the parts of housing 21, epoxy may be employed between surfaces 31 and 32 to achieve a positive blocking engagement.

A passageway 33 in forward end portion 22 permits communication between the forward edge of end portion 22 and chamber 26. Cannula 24 is mounted in passageway 33 with a rear blunt end portion 34 extending into chamber 26 and a forward end portion terminating in tip 35 extending forward of portion 22. Tip 35 is pointed to provide a penetration end for venipuncture purposes.

Rear end portion 23 of the housing has a cylindrical principal portion 36 for engagement with forward portion 22 and to provide the majority of the boundary for chamber 26. The remainder of rear end portion 23 has a reduced outer diameter which includes a threaded surface 37 for threaded interengagement with a holder 38. Holder 38 is utilized as a guide for an evacuated collection container 39. A tube 40 containing at least a partial vacuum is closed at its open end by a self-sealing punctureable stopper 41 to form evacuated container 39.

Rear end portion 23 contains an axial passageway 42 providing communication from the rear end of housing 21 into chamber 26. Cannula 25 is slidably mounted in passageway 42.

The rear end of cannula 25 extends outwardly from housing 21 and has a pointed tip 43 for penetration through stopper 41 of evacuated container 39. Cannula 25 is slidably mounted in passageway 42 of housing portion 36 and has its inner end 44 extending into chamber 26. Adjacent the inner tip of cannula 25 is a side opening 45 which is shiftable into and out of chamber 26 as cannula 25 slides during operation of the needle assembly. Sealing disc 30 rests against the rear wall of chamber 26 and has a central opening therein smaller in diameter than the outer surface of cannula 25 so that the elastomeric sealing disc 30 retains sealing engagement with cannula 25 as it slides with respect thereto. In this manner, the integrity of chamber 26 is retained and leakage is prevented at the rear end of housing 21. To assist in the sealing function of disc 30, rigid sealing disc 29 is positioned in the rear end of housing 21 in frictional engagement with the side walls of the housing and retaining elastomeric disc 30 between its undersurface and the rear wall of the housing. An annular ring 46 projecting from the housing engages with the surface of disc 30 opposite the retaining disc 29 in order to assure a clamping engagement with disc 30 and preventing leakage from chamber 26 through passageway 42 of housing 21.

Mounted on the inner blunt end portion 44 of cannula 25 is cage 28. The mounting can be achieved in any convenient manner such as by an epoxy resin 47. Cage 28 may be constructed of a plastic material and closes the end of end portion 44 of cannula 25. This leaves the only access from chamber 26 into the bore of cannula 25 through side opening 45. Cage 28 has a closed end mounted on cannula 25 and an opposite open end and adjacent to the closed end are a number of transverse side ports 48, for example, four, as shown. The side ports are spaced about the circumference of cage 28. The outer diameter of cage 28 is less than the inner diameter of housing 21 so that cage 28 is free to slide axially as sliding needle 25 slides. The cage 28 is cylindrically shaped and hollow so as to receive the major portion of sleeve 27 therein with clearance for the cage 28 to slide reciprocally with respect to sleeve 27. The cylindrical rim at the open end of cage 28 engages with flange 50 on the circumference of the open end of sleeve 27. The open end portion of sleeve 27 is mounted on the rear end 34 of cannula 24. Cannula 24 is fixed in passageway 33 of housing 21 by any convenient means such as epoxy 51. Sleeve 27 has its open end expanded so that it frictionally engages with the rear end portion 34 of cannula 24 in sealing relationship. Sleeve 27 is shiftable to an armed position as shown, for example in FIGS. 4-9 in contrast to its initial unarmed position as shown in FIGS. 2 and 3. The operational sequence of use of the needle assembly will be discussed in detail below. In the unarmed position as shown in FIGS. 2 and 3, sleeve 27 has a central passageway 52 to receive rear portion 34 of cannula 24. Initially, only the forward open portion of sleeve 27 is mounted on cannula 24 and to the rear of blunt tip 53 of cannula 24, the sleeve 27 has one or more transverse holes 54 to provide communication between the interior of sleeve 27 and the exterior thereof. Additionally, adjacent the rear end of sleeve 27 is a slit 55 which is normally in the closed position due to the self-sealing elastomeric properties of sleeve 27. Any well known elastomeric self-sealing material such as natural or synthetic rubber can be utilized for sleeve 27.

The components of housing 21 and cage 28 may be made of transparent plastic parts so that the presence of blood can be readily visible through them for indication purposes. Additionally, sleeve 27 could be constructed of a transparent elastomeric material, however, this is not generally utilized, since the blood will flow into surrounding spaces provided and will be visible through the transparent portions of the housings during indication procedures as will be discussed in detail below. All of the components of the assembly with the exception of the cannulas and the sleeve may be constructed of a standard low cost plastic material or any readily available substitute therefor.

As discussed above, cannula 25 is slidable into and out of the housing a predetermined distance until limited by stops. The force for moving cannula 25 is provided by the friction between cannula 25 and stopper 41 as the evacuated tube 39 is reciprocated within holder 38 during the blood collection procedure. Although slidable, cannula 25 is continuously hermetically sealed relative to its port by elastomeric sealing disc 30 which has been penetrated by cannula 25.

FIG. 1 shows the needle assembly in position for use having been threadedly engaged with a holder 38 and with an evacuated container 39 in position for engagement with the assembly. Fixed needle 24 is supported by cylindrical portion 22 of housing 21 and is hermetically sealed by epoxy 51 or any other convenient manner. The rear end portion 34 of cannula 24 supports the elastomeric sleeve 27. An interference fit exists between bore 52 of sleeve 27 and the outer surface of cannula 24. Transverse holes 54 are located to the rear of cannula 24 in the initial position of the needle assembly 20 as shown in FIGS. 1 to 3. In this manner, an open air passageway is provided from the open tip 35 of cannula 24 through the assembly until it passes through side opening 45 in sliding cannula 25.

When sleeve 27 is pushed forward to encompass all of the rear portion 34 of cannula 24 so that the forward edge of flange 50 of the sleeve rests against inner wall of the housing, the cannula will be positioned so as to occlude transverse openings 54 and cannula 24 will be sealed by cap or sleeve 27.

Sliding cannula 25 supports valve cage 28. The tip of forward end 44 of cannula 25 is inserted into a recess in the rear end of valve cage 28 and is sealed therein by epoxy 47 or any other common sealing means. The inner diameter of cylindrical cage 28 is substantially greater than the outer diameter of sleeve 27 so that blood or air can readily flow out of the valve sleeve 27 around the spaces between sleeve 27 and cage 28, and out through one or more of the ports 48 of cage 28.

As shown in FIG. 10, portion 22 of housing 21 has a tapered exterior surface 31 which mechanically fits and supports and seals portion 32 of the cylindrical rear portion 23 of housing 21. Rear portion 23 supports sliding needle 25 which is mounted in a close sliding fit within passageway 42 through rear end portion 23. Rear end portion 23 also supports elastomeric sealing disc 30 and the retaining disc 29. Retaining disc 29 is a plastic molded part. It may be constructed of any other common material for the purpose required. It has an outside diameter which is an interference fit relative to the narrowed region of the inside of rear housing portion 23. In assembly of this seal, rear portion 23 is positioned vertically. Then the elastomeric sealing disc 30 is dropped inside. It is positioned to lie flat across the end of passageway 42. Then the sealing disc 29 is dropped in and stops at the narrowed portion 56 of rear end 23. Then a small press or similar device is used to push disc 29 down as far as it will go. The annular ring 46 projecting from the inner surface of portion 23 bites into the elastomeric disc 30 under this pressure thereby assuring a continuous seal.

Then, the cage 28 is joined to the tip of needle 25 by epoxy or any other common affixing means. Thereafter, the pointed end 43 of needle 25 is passed through the central hole of retainer disc 29 and pierces the elastomeric disc 30 and is then pushed into its final position as shown in FIGS. 1-3. The cylindrical member forming end portion 22 including cannula 24 is inserted into rear end portion 23 until the tapered portions meet and seal. This action also inserts a partial amount of end portion 34 of cannula 24 into the open end of sleeve 27. The assembly is then positioned for use as depicted in FIG. 3.

In operation, threaded outer surface 37 of rear end 23 is screwed into the threaded receiving surface of holder 38 in a conventional manner. An evacuated container 39 is then positioned in the rear part of holder 38 in position for use. This arrangement is depicted in FIG. 1 of the drawings. The operator should not couple any portion of the stopper 41 with the rear end of cannula 25 before inserting cannula 24 into the vein of a patient. In this manner, effectiveness of the blood flow indication portion of the needle assembly will be assured.

Then, as shown in FIGS. 2 and 3, tip 35 of cannula 24 is inserted into the patient's vein. At this point, a continuous open passageway exists through the device in the following manner. Blood will pass through cannula 24 and out through transverse holes 54 in sleeve 27. It will then flow through the space between the outside of sleeve 27 and the inside of cage 28 until it passes out through ports 48 of cage 28. At this point, the blood will begin to fill the substantial cylindrical space outside of cage 28 within chamber 26. If the blood is permitted to continue to flow, it will pass through the side opening 45 in sliding cannula 25 and out through tip 43 of cannula 25. The venous pressure of the patient's blood causes the blood to flow unopposed through this series of open passageways. When it substantially fills the chamber 26, it will obviously be visible and the operator, who will be watching for this blood flow indication, will then push the evacuated container 39 all the way into holder 38 so that cannula 25 penetrates through stopper 41. This action of pushing the tube 39 all the way into holder 38 will force needle 25, first, to slide forward so that sleeve 27 is forced all the way onto rear portion 34 of cannula 24 and sleeve flange 50 abuts against the interior surface 57 of housing 21 which provides a positive stop. The transfer will be accomplished by the interconnection between cannula 25, cage 28, and sleeve 27. The only restriction to the sliding of needle 25 is the friction between sealing disc 30 and the outside surface of cannula 25. This amount of friction is made substantially less than the friction encountered when cannula 25 penetrates stopper 41. In this way, sleeve 27 will be moved to its position for operation as a valve member before cannula 25 pierces into the evacuated tube 40 of container 29. Sleeve 27 stays in operating position as a valve member thereafter. FIGS. 4 and 5 show the assembly after sleeve 27 has been transferred to its forward position where it will act as a valve member and just prior to penetration of stopper 41 by cannula 25.

In FIGS. 6 and 7 the forward movement of the evacuated container has been completed and communication is provided between cannula 25 and the interior of tube 39. As shown, this causes slit 55 to open in view of the pressure differential provided by the vacuum within container 39 and blood to flow into tube 40 along the path as shown by the arrows in FIG. 7. After the tube 40 is filled with blood, and it is desired to fill one or more additional tubes, the operator pulls container 39 out of the holder. In doing this, the friction between stopper 41 and cannula 25 is substantially greater than the friction between cannula 25 and sealing disc 30, so that cannula 25 is moved rearwardly until the rear end of cage 28 abuts against retaining disc 29 which provides a positive stop. This action is completed before cannula 25 is pulled out of stopper 41. In this position, side opening 45 of cannula 25 is to the rear of sealing disc 30 and, therefore, no more blood can flow out of cannula 25 until the next container 39 is inserted all the way into the holder. Insertion of the following container 39 will once again force cannula 25 and cage 28 forward exposing opening 45 to the interior of chamber 26 and permitting blood to flow into the container when cannula 25 is fully subjected to the interior of evacuated tube 40. The closed position at the end of collection of a first sample and prior to insertion of a second collection container 39 is depicted in FIGS. 8 and 9 of the drawings. It should be noted that tip 35 remains in the vein thereby enabling multiple samples to be taken in a succession of collection containers with only a single venipuncture. After the desired number of samples have been taken, the assembly is disposable and can be discarded.

In summary, needle assembly 20 performs a combination of functions. It provides a one-way valve which is normally closed and alleviates the danger of back flow during blood sampling procedures while at the same time providing a blood flow indication means to notify the operator when a proper venipuncture has been accomplished as well as providing a multiple sampling device.

Thus, the above objectives of the present invention, among others, have been effectively attained.

Claims

I claim:

1. A needle assembly for facilitating the collection of a blood sample from a patient by first indicating when a venipuncture has been accomplished, then transferring blood from the patient into an evacuated container, while preventing any back flow from the container into the patient, and automatically blocking the blood flow due to venous pressure while shifting to successive sample tubes to be filled with the same venipuncture, said needle assembly comprising:

a housing having a chamber therein;

a forward penetrating end including a cannula extending from the housing for penetration into the blood vessel of a patient;

a rearward end including a cannula extending from the housing and adapted to be coupled in fluid communication with the interior of an evacuated collection container;

surfaces of said assembly to form a passageway for directing blood the blood vessel through the housing to the collection container when the forward end is in the blood vessel and the rearward end is in the container;

a valve assembly mounted in the chamber in the housing and normally in the unarmed position with passages therein to permit blood to flow from the vein into the chamber upon venipuncture and being shiftable to an armed position to close the passageway from the vein into the chamber by means of a resilient elastomeric valve member in the chamber;

said valve member adapted to be responsive to a reduction in a fluid pressure at the rearward end to deform and automatically open the passageway and permit blood to flow from the blood vessel to the rearward end and into a container, thereafter to be responsive to a predetermined increase in fluid pressure at the rearward end to automatically return to the closed position to thereby prevent flow of fluid from the rear end of the assembly to the blood vessel; and

the rear end of the penetration cannula being mounted in the forward penetrating end of the housing extends rearwardly into the chamber of the housing; an elastomeric sleeve slidably mounted on the rear end of the penetration cannula in sealing engagement therewith, the sleeve being shiftable between an unarmed position and an armed position on said penetration cannula, the sleeve having a closed rear end and a forward open end with the penetration cannula mounted in the open end of the sleeve, at least one transverse hole in the wall of the sleeve permitting communication between the rear end of the penetration cannula and the exterior of the sleeve when the sleeve is in the unarmed position and said at least one transverse hole being closed when the sleeve is shifted to the armed position, a slit in the wall of the sleeve normally in closed position when the sleeve is in the armed and unarmed position and adapted to automatically open when there is a reduction in fluid pressure at the rearward end and thereafter to automatically close when there is a predetermined increase in fluid pressure at the rearward end, and an annular flange extending from the forward open end portion of the sleeve to facilitate engagement of the sleeve and shifting of the sleeve from the unarmed to the armed position.

2. The invention in accordance with claim 1 wherein the cannula extending from said rearward end is slidably mounted and has been inserted after a tubular hollow cage is mounted on the slidable cannula in the chamber of the housing in surrounding relationship to the elastomeric sleeve, the cage being in engagement with the flange on the sleeve so that shifting of the slidable cannula will shift the cage and the engaged sleeve from the unarmed to the armed position when moved in one direction and will disengage from the sleeve when the slidable cannula is moved in the opposite direction.

3. The invention in accordance with claim 1 wherein the housing is made of a transparent material.

4. The invention in accordance with claim 2 wherein there is at least one transverse opening in the side walls of the cage to permit communication with the at least one transverse hole in the sleeve so that when the sleeve is in the unarmed position and a venipuncture is accomplished, blood will flow through the penetration cannula, through the at least one transverse opening in the sleeve and through the at least one transverse opening in the cage into the chamber of the housing to provide an indication that the venipuncture has been accomplished.

5. The invention in accordance with claim 2 wherein the cage is mounted on the inner end of the slidable cannula so as to seal the end thereof and the slidable cannula has a side opening therein adjacent the rear end thereof so as to be positioned within the chamber of the housing when the sleeve is in the unarmed position and when the sleeve is in the armed position and a collection container is coupled in fluid communication with the slidable cannula, and the side opening being shiftable out of the chamber of the housing and being sealed therefrom by the elastomeric sealing disc when a collection container has been removed from the slidable cannula and the slidable cannula has been withdrawn until surfaces on the cage engage with surfaces in the housing to provide a stop to further withdrawal of the slidable cannula.

6. Apparatus for collecting multiple blood samples from a patient including the combination of:

A. a housing;

B. a first hollow, pointed needle extending forwardly from the housing adapted for piercing the tissues of a patient and conducting blood therefrom;

C. blood flow indicating means coupled with said first needle and adapted to provide a visual signal when the needle has penetrated a blood vessel;

D. a check valve means coupled with said first needle and adapted to assume a first position to enable blood to flow out of the patient and a second position to prevent any fluid from flowing back into the patient;

E. a chamber in the housing in fluid connection with said check valve;

F. a normally closed second valve means, and adapted when closed to prevent any blood from flowing out of said chamber; and

G. a second hollow pointed needle means extending rearwardly from the housing and having surfaces forming part of said second valve means; said second needle means adapted to be moved from a first position to a second position, and adapted to actuate said second valve means, whereby when the second needle means is in its first position said second valve means is closed, and when said second needle means is in its second position said second valve means is open to permit flow of blood from the patient to a blood container, and as many other prescribed containers with one penetration of the tissues of a patient with the first needle without blood spillage when changing containers.

7. The invention in accordance with claim 6 including a blood container with a resilient closure containing a partial vacuum, so positioned and arranged that when said container is pushed forward the resilient closure pushes the second needle means forward, which causes the second valve to open and causes the second pointed needle means to penetrate through the resilient closure, thereby enabling the patient's blood to substantially fill the container, and when the container and resilient closure are pulled backward off the second needle means, this needle means moves causing the second valve means to close, thereby preventing any further flow of blood until another of said blood containers is used.

8. The invention in accordance with claim 6, wherein said blood flow indicating means includes a passageway enabling air and blood to flow into said chamber while bypassing said check valve means.

9. The invention in accordance with claim 8, including means for automatically closing said bypass passageway when the blood container is coupled with the second hollow pointed needle means.

10. The invention in accordance with claim 6, including means for automatically moving said check valve means from an inoperative position to an operative position when the second needle means is coupled with the blood container and moved in the forward direction.

11. The invention in accordance with claim 6, including means for automatically changing said second valve means from a closed condition to an open condition when the second needle means is coupled with the blood container and moved in the forward direction.

12. The invention in accordance with claim 6, including means for automatically closing said second valve means when the second needle means is coupled with and the blood container withdrawn in the backward direction.

13. The invention in accordance with claim 6, where said check valve means is made of a deformable resilient material having a cylindrical shape closed at one end and having at least one slit opening, normally closed, said slit opening adapted to open automatically when the interior of said check valve means is subjected to a greater fluid pressure than the exterior fluid pressure, and the slit also is adapted to close automatically when this pressure differential is absent or is reversed.

14. The invention in accordance with claim 6, including pusher means cooperating with said check valve means, said check valve means including at least one bypass passageway initially open, whereby said bypass passageway is automatically closed when said pusher means slides the check valve means axially along the inner end of said first hollow needle so that the bypass passageway is occluded by said first needle when second needle means is coupled with the blood container closure and pushed in the forward direction.

15. The invention in accordance with claim 14, wherein the check valve means includes a flange portion and said pusher means includes a hollow cylinder of rigid material mounted on the inner end of the second hollow pointed needle means and is adapted to engage the flange portion of said check valve means, whereby when the second needle means is coupled with the blood container and pushed in the forward direction the rigid hollow cylinder attached to it pushes the check valve means in the forward direction until the bypass passageway is closed.

16. The invention in accordance with claim 6, wherein the second valve means includes an elastomeric seal adapted to maintain a fluid-tight seal between said second needle means and said chamber.

17. The invention in accordance with claim 16, wherein the second valve means includes an annular projecting ring portion in the seat of said elastomeric seal.

18. The invention in accordance with claim 16, wherein the second valve means includes a retainer disc having an interference fit with a portion of said chamber to retain said disc and said elastomeric seal in place and having a clearance hole through which said sliding second needle means extends.

19. The invention in accordance with claim 6, where said chamber is defined by a forward housing portion and an attached rearward housing portion including a transparent portion adapted to transmit a visual indication of blood flow.

20. The invention in accordance with claim 19, wherein the forward housing portion supports the first needle and check valve means.

21. The invention in accordance with claim 19, wherein the rearward housing portion supports the second hollow needle means and second valve means.

22. The invention in accordance with claim 16, wherein said second needle means has a side opening cooperating with said elastomeric seal to act as said second valve means.

23. The method of transferring blood from a patient into a blood sample assembly and container which includes the steps of:

A. inserting a first sharp pointed hollow needle into a patient's blood vessel;

B. conducting the patient's blood through said first needle and into a blood flow indicator;

C. pushing in the forward direction a partially evacuated blood collecting container with a resilient closure after the blood flow indicator has shown that the first needle has been successfully inserted in the patient's blood vessel, causing a second hollow pointed needle to penetrate through the resilient closure; and so that the blood container is operatively connected with the blood sample assembly;

D. actuating a check valve incident to said forward pushing of the blood container insuring that blood can flow from the patient into the blood container but that no fluid can flow back from the container into the patient;

E. opening an exit valve between a chamber of said blood sample assembly and the second hollow pointed needle incident to said forward pushing of the blood container;

F. transferring blood from the patient's blood vessel under the influence of the partial vacuum, through the first needle, through the check valve, through the chamber of the assembly, through the exit valve, and through the second needle until the blood container is substantially filled;

G. removing the filled blood container in the backward direction and thereby closing the exit valve;

H. repeating the foregoing steps C to G; and

I. in the same manner filling as many blood containers as desired with a single puncture of the patient's blood vessel.