HEMOSEAL BLOOD COLLECTION DEVICE

Abstract: Devices for collecting blood samples from a patient. The devices include a receptacle (16) for receiving the blood and having a bung (14) at a first end and an opening (44) at the other end, and a piston (18) which is normally adjacent the bung (14). An elastomeric element (20) extends between the piston (18) and the other end and projects through the opening (44) to permit pulling the piston (18) towards the other end thereby inspiring blood through the needle (10) into the receptacle (16). A double ended needle (10) is also provided contained in a holder (24) and adapted to receive the receptacle to bring the needle (10) into a position for engagement in a vein.

Description: HEMOSEAL BLOOD COLLECTION DEVICE This invention relates to devices used to collect samples of blood from patients for subsequent laboratory testing and analysis. It is desirable that blood sample collection be done expeditiously and with a minimum of discomfort to the patient. These criteria call for efficient insertion of a needle into a vein, connection to a receptacle for retaining the blood 'without dislodging the needle, and also the facility to replace the receptacle for taking more than one blood sample with the needle in the same position. The most widely used structure consists essentially of three parts. Firstly, a double-ended needle having a threaded connector between its ends, and covers attached one to each end of the connector and containing one end of the needle. These covers retain the needles in a clinically clean condition and must be removed before connection to a holder. After removing the covers, one end of the needle is inserted through an opening at the end of the holder and the needle device threaded in place in the holder. The assembly is then used to insert the other end of a needle into a vein, and then the third element, an evacuated receptacle, is inserted into the holder where a bung in the end of the receptacle is pierced by the end of the needle in the holder to permit blood to pass through the needle into the receptacle. Because the receptacle is evacuated, blood is drawn through the needle to fill the receptacle after which the receptacle can be withdrawn from the holder and a further receptacle engaged over the needle to receive another blood sample. Although this structure has achieved great success in the marketplace and is used extensively, it does suffer from disadvantages. Firstly, when the covers are removed from the needles, it is not uncommon for the person using the device to contaminate the needle by catching it on the skin or even to pierce the skin accidentally. There is a further danger of this happening when the needle is connected to the holder and this part of the procedure requires considerable dexterity to SUBSTITUTE SHEET \ - avoid needle contamination and minor lacerations. Next, after the needle and holder have been positioned by inserting the needle in a vein, the receptacle must be connected. This requires some force and there is some difficulty in avoiding transmitting some of the force to the patient. There is therefore a possibility that this attachment can result in damage to the vein, or at the very least, some discomfort. It is to be noted that this order of events is necessary due to the fact that the receptacle is evacuated and can only be connected after the needle is inserted in the vein. Further difficulties arise after the needle is removed. The contaminated needle must be unscrewed from the holder after first replacing a cover over the needle. Obviously the user can come into contact with the end of the contaminated needle with undesirable consequences. Other disadvantages are not readily apparent. After attaching the receptacle, because of its evacuation, blood tends to rush into the receptacle. This can cause local collapse of the vein as well as damage to the blood due to violent impact on the internal wall of the receptacle to turbulence within the needle, and the sudden exposure of blood cells to the vacuum within the receptacle. Further, there is no control over the volume of blood withdrawn; the receptacle receives blood until no further flow takes place. Where a number of samples are required for different tests, the number of receptacles used will match the number of tests. This can result in a considerable volume of blood being drawn, when in fact some of the tests may require only a fraction of the volume of a particular receptacle. In currently used systems the vacuum within the receptacle degrades with time. It is very common for the user to find a receptacle in which part or all of the vacuum has been lost. This results in only partial filling of the receptacle with blood, often resulting in the sample being useless for testing. There is no way that the user can determine the condition of the vacuum prior to attempting to draw the sample. SUBSTITUTE SHEET C PJ__ ' The present invention provides a structure which is intended to overcome the aforementioned disadvantages, and to provide a commercially acceptable alternative for the structures presently in use. To this end, a receptacle is provided for use with a needle and holder and containing a piston which is drawn away from the needle to inspire blood into the receptacle. The piston is withdrawn using an elastomeric element which stores energy so that the piston cannot be withdrawn suddenly thereby obviating sudden large pressure fluctuations in the needle and hence in the vein. The invention will be better understood with reference to the drawings in which: Fig. 1 is a sectional side view of a preferred embodiment of a blood collection device according to the invention in an assembled condition ready for use; Fig. 2 is a view similar to Fig. 1 showing a combination needle and holder sub-assembly as it would be supplied for use in the device and prior to assembly; Fig. 3 is an end view of a receptacle used in the device; Fig. 4 is a perspective view of part of the device and a tool used in the assembly drawn to a larger scale than that used for Figs. 1 and 2; Fig. 5 is a partial view similar to Fig.l illustrating an alternative embodiment of the device; Fig. 6 is perspective view of a conventional needle and holder assembly with some modification and also showing an adaptor for use with this assembly; Fig. 7 is a view similar to Fig. 1 and showing part of an alternative embodiment of the invention; and Fig. 8 is a view similar to Fig. 1 and illustrating yet another embodiment of the invention. Reference is first made to Fig. 1 which illustrates a preferred embodiment of the invention after assembly. This structure consists essentially of a double ended needle 10 which is attached to a collar 12 such that the needle projects inwardly beyond the collar to pierce a septum of a bung 14 S UBSTITUTE SHEET associated with a receptacle 16. In use blood flows through the needle inspired by movement of a piston 18 attached to an elastomeric element 20 which projects through an opening at the end of receptacle 16 to permit the user to pull the piston towards this end of the receptacle. The collar 12 is a snap fit in the neck 22 of a holder 24 and the receptacle 16 is retained in the holder by an annular rib 26 on the receptacle which engages in a corresponding depression 28 at the mouth of the holder 24. To use the structure shown in Fig. 1, it is supplied initially as two distinct parts. Reference is made to Fig. 2 to show one of these parts which it will be seen consists of the needle 10 and the collar 12 engaged within the holder 24 and sealed by removeable end covers 30, 32. It can be seen in Fig. 2 that the collar 12 extends axially into a skirt 34 which positions the needle 10 inside the holder 24. To engage the receptacle 16, the end cover 32 is removed by simply tearing it away from the holder and if necessary the end cover 30 can also be removed in this way. However, .this cover can simply be pierced by the needle and pushed out of the way as the parts are assembled. Once end cover 32 has been removed, a receptacle is engaged in the holder and because of the position of the needle, the bung is pierced in the receptacle as it is pushed towards the neck 22 of the holder 24. Continued axial movement of the receptacle will cause the parts to take the position shown in Fig. 1 in which the collar 12 has been snapped through the neck 22 for positive location to prevent movement of this part back into the holder once the receptacle is removed. Also, positive location is provided as already mentioned by the engagement of the rib 26 in the depression 28 of the holder. This is not necessarily a positive engagement because the user can displace the receptacle transversely while holding the assembly so that a portion of the rib 26 sits in the depression 28 to locate the receptacle axially. Once the assembly is in the position shown in Fig. 1, the needle can be inserted into a vein and a small opening 36 in the needle provides a visual SUBSTITUTE SHEET -$£ indication that blood is available because the parts around this opening are made of a transparent plastic material. If necessary the material can be shaped to give some magnification. As blood is available in the needle, it will find its way into a cavity 38 formed both by the bung 14 and piston 18. The cavity is sealed because the bung includes an annular lip 40 which is inter-engaged with an annular depression in the piston. On pulling the element 20, the user causes this inter-engagement to be disturbed and the piston to move towards the other end of the receptacle. In order to prevent the piston seizing inside the receptacle during storage, the wall of the receptacle has a larger diameter where the piston is stored and upon moving the piston slightly it engages a reduced or working diameter by riding over an inclined step 42 on the inner wall of the receptacle. The piston then forms a seal with the inside wall of the receptacle as it travels from this point and can be stopped whenever that sufficient blood has been removed. An important aspect of the invention is the fact that when the user pulls the elastomeric element 20, energy is stored in this element so that the piston cannot be moved suddenly to cause an instantaneous pressure drop in the patient's vein. Further, by pulling out the element 20 slowly or in small increments, the blood will be drawn smoothly and without causing sudden large pressure variations in the vein. Consequently it is possible to draw blood without collapsing the vein or causing impact and turbulence when the blood enters the receptacle. The wall of the receptacle 16 can be graduated if required and the user would simply pull out the element 20 until the blood meets the chosen graduation on the outside of the receptacle. The desired volume of blood is then contained in the receptacle. After withdrawing blood, the user can remove this receptacle from the holder 24 without dislodging the needle from the patient and then enter a further receptacle if another sample is required. SUBSTITUTE SHEET / OV.PI Λ WiPO Λ It should be noted that the foregoing procedure reduces the likelihood of the user accidentally damaging himself or the patient with the needle during assembly of the parts. This is because the needle is contained in the holder and is only exposed when the receptacle is engaged. The element 20 is engaged through an opening at the end of the receptacle as previously mentioned. This opening is illustrated at 44 in Fig. 3. The opening is quite narrow so that it grips the elastomeric element 20 to permit storage of energy in the element by withdrawing the element faster than the piston moves. This in effect allows quite a simple procedure because the person operating the device does not have to continually pull the element because of the storage of energy. The element as mentioned can be pulled to a predetermined position or alternatively simply pulled a suitable amount and the piston allowed to catch up before pulling it further. During assembly it is necessary to engage the elastomeric element 20 and withdraw it from the bung-end of the receptacle through the opening 44. This is done by use of a simple tool 46 as illustrated diagrammatically in Fig. 4. This tool is proportioned to engage a tool peg 48 in the opening held in place by a rearwardly projecting lip 50. The peg 48 is proportioned to pass through a slotted opening 52 formed in the elastomeric element which, as it can be seen in Fig. 4, is shaped in a complementary fashion in relation to the tool for engagement with the tool so that it can be withdrawn along with this part of the tool through the opening 44 in the receptacle. Suitable jigs would of course be used to ensure engagement and it is envisaged that an end load would be provided on the element 20 to deform the end so that the opening widens for engagement of the tool. An alternative embodiment of holder is shown in Fig. 5. The neck 56 of this holder is proportioned to receive the needle and does not take part in locking the needle and associated collar 58 to the holder. To do this one or more dimples 60 are provided on the inside wall of the holder so SUBSTITUTE SHEET that when the collar 58 and its associated skirt has passed these dimples, the collar is retained in position together with the needle. This also shows an alternative arrangement for the needle itself. It will be seen that an elastomeric cover 62 is provided which will be pierced when the bung is pressed against the end of the needle. However when the receptacle is removed for engagement of a further receptacle, the resilience in the cover 62 will cause it to return to the position shown in the drawing and to contain any blood which might otherwise spill into the holder. This tends to reduce the likelihood of droplets of blood appearing on the sides of the receptacle in an unsightly fashion. Reference is next made to Fig.6. There are currently in the marketplace a large number of holders used in association with prior art devices. In order to make use of these holders, there are two simple modifications which can be made, either one of which will permit the present receptacle to be used with the holder. Both of these modifications are incorporated into Fig. 6 where it will be seen that two large openings 64 have been cut in the wall of the holder and this permits the user to grip the receptacle after it has been engaged in the holder and thereby hold it in place during removal of blood. An alternative approach is to provide a collar 66 having upstanding latches 68 for engagement over an existing flange 70 at the flats on the flange. The collar includes inwardly formed ribs or projections 72 so that when in position these will allow the rib 26 (Fig. 1) to pass but will contain the receptacle by engagement with this rib. Reference is now made to Fig. 7 which illustrates an alternative embodiment of receptacle and associated bung. In this embodiment a bung 74 combines with a filmic cover 76 to define a cavity 78 which, like the cavity 38 in Fig. 1 can retain a liquid which is added to the blood automatically to facilitate various tests conducted in the laboratory. As seen in Fig. 7, a needle shown in ghost outline would penetrate both the bung and the cover and the piston would be withdrawn in the normal way although in this S UB S TITUTE SHEET embodiment the piston is not interlocked with the bung. After removal of the blood, the needle would be disengaged and because the cover 76 is penetrated, the liquid would fall out into the blood and mix as required. This contrasts with the Fig.. 1 embodiment in which the liquid used in the testing would be preassembled between the piston and the bung and a complete receptacle would be designated for use in accordance with the material contained between the bung and the piston. The Fig. 7 embodiment requires only that the bung and its contents be stored leaving the remainder of the receptacle including the piston for use with any particular type of bung and liquid contained in the bung. This obviously facilitates reduced storage expenses since a number of different liquids can be stored in colour coated bungs whereas previously it was necessary to store a variety of complete receptacles. It will also be evident that the cover 76 could be broken by any suitable structure on the piston coming into contact with the cover when the bung is inserted. The materials used in the manufacture of the various embodiments can be any synthetic plastic material having suitable characteristics conventional in the art. However preferably the bung 14, the piston 18 and the tail 20 comprise a flexible urethane, although they may alternatively be made of anysuitable elastomeric material or rubber, and the holder 24, and collar 12 are made of polypropylene, although they may also alternatively be made of any other suitable inert material. Finally, reference is made to Fig. 8 which illustrates another embodiment of the invention. Parts corresponding generally to those described with reference to Fig. 1 have been given primed numerals to simplify comparison. It will be seen that a receptacle 16' contained in a holder 24' associated with a needle 10'. In this embodiment, the holder 24' has a forward boss 80 which is threaded to receive a needle holder 82 having the needle 10' embedded in the holder and projecting inwardly of the holder 24'. This is a conventional needle assembly and is adapted into this holder to demonstrate that such a needle assembly can be used with the present invention. However, the SUBSTITUTE SHEET Oi FI , VΛ. lvi'o holder differs from prior art holders in that it combines with the receptacle 16' to retain the receptacle in position using a very simple structure. It will be seen that the wall of the receptacle 24' (as drawn at the top of the view) has a central annular portion 84 which is thinner at the bottom of the section as drawn than at the top. This thinner wall represents an area of reduced thickness and is associated with an internal ridge 86. Because the wall is thin in this portion, it can deflected inwardly to bring the ridge into a position where it abuts an annular shoulder 88 on the receptacle 16' to prevent removal of the receptacle while this deflection occurs. There are preferrably two areas of thinned wall associated with ridges such as the ridge 86 so that the user can readily deflect an appropriate one of these portions into engagement with the shoulder 88. As soon as the user permits the wall to return to its original shape, the receptacle 16' can be withdrawn from the holder 24'. It will also be seen in Fig. 8 that the piston 18' has a different form from previous pistons described with reference to the other drawings. The form of this piston is particularly appropriate for this structure because it lends itself to inter-engagement with the bung 14 ' and as soon as it separates from the bung, the outer portion of the piston can deflect and the reactive force ensures a seal with the inner wall of the receptacle once the piston has passed the step 42'. It should also be noted that where the piston 18' meets the element 20', there is a weakened portion 90 so that when the element is withdrawn through the end of the receptacle, the portion 90 will meet the opening 92 at the end of the receptacle and this opening is shaped to define a keen edge at its outer limit so that the user can pull the element 20' sideways and cause this edge to sever the element from the piston at the portion of weakness 90. Of course should the user decide to withdraw only a small sample of blood, then the piston will not be drawn to the end of the receptacle and the element 20' can either be severed by working it in the opening until it breaks or snipping it using a pair of scissors. SUBSTITUTE SHEET It will be appreciated that it is preferable not to have any positive locking between the receptacle and the holder because to separate these parts the force required may result in a jarring reaction. Consequently, the type of structure shown in Fig. 8 where the receptacle is held in place by deforming the wall is particularly appropriate because once the wall is released, the receptacle can be removed without the need for an increased force to cause initial separation. This, of course, also applies to the Fig. 1 structure provided that the tolerances are chosen so that the rib 26 does not inter-engage with the depression 28 positively. It will be appreciated that the foregoing embodiments are exemplary of the invention and that they should not be used to limit the scope of the accompanying claims. W -A Ϊ V I

Claims: WE CLAIM: 1. A device for use in collecting blood samples from a patient, the device comprising: a receptacle having a bung at a first end and an opening at the other end and defining an internal surface; a piston adjacent the bung and in engagement with the internal surface; and an elastomeric element attached to the piston and extending from the piston through the opening in the other end of the receptacle and terminating outside the receptacle whereby upon piercing the bung with a needle carrying blood, the elastomeric element can be drawn through said opening to cause the piston to move towards said other end thereby inspiring blood into the space between the piston and the bung. 2. A device as claimed in claim 1 in which the receptacle defines a step in said internal surface such that upon moving the piston towards said end the piston is stressed sufficient to cause a seal between the piston and said internal surface. 3. A device as claimed in claim 1 in which the bung and the piston are releasably inter-engaged and define a cavity, the piston being separated from the bung upon moving the piston towards said other end. 4. A device as claimed in claim 2 in which the bung and the piston combine to form a cavity suitable for storing chemicals to be mixed with the blood as it enters the receptacle. 5. A device as claimed in claim 1 and further including means co-operable with a holder to retain the receptacle in position with said needle penetrating the bung. SUBSTΓ • I t ~~ * ~~ t ~ - »_. 6. A device as claimed in claim 1 in which the cross-section of the elastomeric element and the dimensions of said opening are chosen so that the elastomeric element is gripped in the opening to permit stressing the element by drawing some of the element through the opening whereby the energy stored in the element draws the piston towards said other end until equilibrium is established. 7. A device as claimed in claim 6 in which the elastomeric element includes a portion of weakness adjacent the piston to facilitate severing this element after drawing the element through the opening until said portion of weakness lies in the opening. 8. A device as claimed in claim 1 in which the bung defines a cavity and includes a frangible cover closing the cavity to contain chemicals to be mixed with the blood for purposes of analysis. 9. A device as claimed in claim 1 in which the elastomeric element defines an opening outside the receptacle for use in assembling the device. 10. A device for use in collecting blood samples from a patient, the device comprising: a tubular receptacle having a bung closing a first end and a second end formed to define a small opening, the receptacle defining an interior wall having a shorter section of a first diameter in engagement with the bung and a longer section of a fractionally smaller second diameter; a piston adjacent the bung and contained in engagement with the interior wall in the shorter section and immediately adjacent the long section, the piston being proportioned to be in sealing engagement with the interior wall in the second section and to be free of significant stress when in the first section; and SUBSTITUTE SHEET _csi ■ an elastomeric element having a cross-section proportioned to be gripped by the receptacle in said opening, the element being attached to the piston and extending through and beyond the opening to provide for gripping the element to draw the piston towards said other end of the receptacle whereby upon piercing the bung with a needle carrying blood, the elastomeric element can be drawn through said opening to cause the piston to move towards said other end thereby inspiring blood into the space between the piston and the bung. 11. A device as claimed in claim 10 in which the bung and the piston are releasably inter-engageable and define a cavity for containing chemicals to be mixed with the blood. 12. A tubular holder for use in maintaining a needle assembly in engagement with a receptacle used to receive blood from the needle when the needle is inserted into a patient's vein, the holder including means at a first end for locating the needle and having an interior surface defining means co-operable with the receptacle to retain the receptacle in the holder and positioned such that the receptacle and needle are in operable engagement with one another. 13. A tubular holder as claimed in claim 12 in which the means co-operable with the receptacle is an interior ridge and in which the wall of the holder is weakened in the region of the ridge for deflecting the ridge inwardly in use to engage the receptacle and retain the receptacle inside the holder. 14. A tubular holder as claimed in claim 13 in which the means at the first end is an internally threaded boss for receiving a body having a complementary thread and carrying the needle. 15. The combination of a device as claimed in claim 1 and a holder as claimed in claim 13. SUBSTITU E SHEET -oDRtA L/ J I 16. A device for collecting blood samples from a patient, the device comprising: a double-ended needle; a holder containing the needle; a receptacle having a bung at a first end and an opening at the other end, a piston adjacent the bung and an elastomeric element extending from the piston through the opening for moving the piston along the length of the receptacle whereby on assembly the receptacle is engaged in the holder with one end of the needle through the bung and the other end of the needle available for piercing a vein so that by pulling on the elastomeric element the piston moves to inspire blood through the needle and into the receptacle. 17. A receptacle for receiving a blood sample, the receptacle having a bung at one end piercable by a needle and an opening at the other end; a piston adjacent to the bung; and an elastomeric element atached to the piston and extending through the opening for manually pulling the element whereby the piston can be moved to inspire blood into the receptacle. 18. A bung for use with a blood-receiving receptacle, the bung having a septum for penetration by a needle and defining a depression, and a filmic cover over the depression to contain in the depression a liquid used with the blood in selected laboratory procedures, the filmic cover being severable in use to permit the liquid to mix with the blood. TϋREA O. PI

Inventors: MALCOLM CRAIG, MALCOLM RICHARD E, SHEPHERD CHARLES GRAY
Applicants: HEMOSEAL PARTNERSHIP, MALCOLM DAVID H
Application year: 1982
Main classification: A61B5
IPC codes: A61B5