Device for the extraction of blood

Abstract

The invention relates to a device for the extraction of blood comprising a sleeve and a piston which can be fabricated simply and economically and whereby the sleeve of which is suited for subsequent centrifugalizing in the same way as a conventional centrifuge tube. This invention is characterized in that a tube closed at one end is used as a sleeve and that a punctured piston is used having a tubular piston rod adjacent thereto, whereby at the free end of said piston rod projecting from the tube there are disposed lateral handles and the connecting socket for applying a tubule.

Description

This invention relates to a device for the extraction of blood, comprising a sleeve, a piston guided shiftable and liquid-tight therein and a socket communicating with the interior for applying a tubule.

Such devices are known in the form of syringes which are also used to inject liquid. In recent times such syringes have been formed in such a way, in particular in case they are used for extracting blood, that they are used only once and then are disposed off. These syringes have already been sterilized by the manufacturer and have been packaged sterile so that for the doctor the activity of sterilizing is eliminated. Also it is rendered impossible when using such syringes once that syringes already used are used a further time without a subsequent cleaning and sterilization or after an incomplete sterilization and result in an infection of the second patient.

Provided blood is extracted from a patient with such syringes and is to be centrifugalized, this blood is subsequently injected into a centrifuge tube. This tube is closed by a plug by the doctor or in the hospital and is transferred to the test laboratory, while the syringe is disposed off.

In order to avoid the filling over required in this regard and to save the special centrifuge tube, it has been proposed to use the sleeve of the syringe as a centrifuge tube, by closing the socket disposed at the bottom of this sleeve after removing the tubule with a special closure cap.

By the fact that the re-injection into a special centrifuge tube is dispensed with, a lesser haemolysis results and confusion and defilement possibilities are eliminated. Also the centrifuge tubes are rendered superfluous.

The disadvantage of this single-use syringe for the extraction of blood, however, is that the bottom of the tube or of the sleeve greatly stresses in the centrifuge is closed by an applied closure cap which can happen to detach or become untight in an adverse instance. In such a case the blood perhaps even containing germs would seep out of the bottom of the tube and would at least pollute the centrifuge, if not perhaps even the environment and depending on circumstances infect it.

Also there is the risk with this conventional single-use syringe that the socket after removing the tubule and prior to applying the closure cap is polluted during the manipulation and possibly is infected. This could in the adverse case detrimentally affect the tests.

An object of this invention is to eliminate the disadvantages of the conventional devices and to provide a device for the extraction of blood which is simple and economical to make and the sleeve of which is suited for a subsequent centrifugalizing in the same way as the conventional centrifuge tube, after removing the piston with the tubule.

This invention resides in the measure that as a sleeve a tube closed at one side and as a piston a punctured piston with an adjacent tubular piston rod is used at the free end of which projecting from the tube there are lateral handles and the socket for applying a tubule.

Prior to use, the piston is pushed completely into the tube, is sterilized and is packed sterile. After puncturing the vein by the tubule the tubule and thus also the tubular piston rod and the piston are held fixed by means of the handles, while the tube is drawn away from the handle. Thereby in the interior of the tube a depression results which causes the entry of blood through the tubule via the tubular piston rod into the bottom area of the tube.

After extracting a sufficient quantity, the tubule is removed from the vein. The piston is drawn out of the tube, and the tube is closed by a plug before it is placed into the centrifuge. Prior to pulling the piston out of the tube, the tubule can be removed, or it can also be left on the socket. The blood contained in the tubular piston rod is not lost for the test, since it when pulling the piston out of the tube, is sucked into the latter.

Since a subsequent refilling of the extracted blood into a centrifuge tube is omitted, the haemolysis is maintained to a minimum possible rating.

The use of additional centrifuge tubes next to the sleeve of the device is dispensed with or this sleeve is defined by the normal centrifuge tube.

In certain applications and in particular for devices according to the main patent in which for the extraction of larger amounts of blood the tube accomodating the piston has a larger diameter, it has proven to be desirable to not arrange the connecting socket for applying an injection needle concentric relative to the tube, i.e. in a greater spacing from the circumference thereof, but eccentric, namely as closely as possible to the circumference of the tube. For this affords substantial advantages upon introducing the injection needle in a vein and the subsequent extraction, for manipulation, because now the tube can be held parallel to the surface of the arm or the like along its entire length and a disturbed holding and thus the risk of an injury of the opposing vein wall with an inclined holding is not provided or is hardly provided anymore.

While now in the conventional blood extraction devices in which the connecting socket is arranged at the end of the tube, i.e., the so called syringe cylinder, and the piston is not bored through, such an eccentric embodiment can be easily provided because of the arrangement of the injection syringes in several parts, this is not possible because of certain difficulties in manufacture for the device according to the main patent in which the piston, the piston rod, the handle and the connecting socket for the injection needle are injection molded in one piece of plastic.

The device for extracting blood, therefore, preferably is furthered in such a way that the piston includes a thin circular disk connected to the guide veins and a thin circular cylindrical collar projecting from the circumference thereof in axial direction.

Even in case of a deviation of the circumference of the circular disk from the desired circular shape the collar projecting from it always will attempt to have its circular cylindrical shape. The collar thus will in all events sealingly engage the inner surface of the tube, in particular with its free edge, even in case of deviations of the disk from the circular shape. By this configuration of the piston the difficulties are eliminated which result in the manufacture of the piston with the piston rod in one piece.

Here also guide wings are provided which extend outwardly from the tubular piston rod and take over the guiding of the piston rod in the tube.

Preferably the bottom of the sleeve can be filled with a substance suppressing a blood coagulation. This substance may also be applied to the inner wall of the tubular piston rod.

It is preferably provided for in this regard that the tubular piston rod conically converges from the opening in the piston toward the socket. Thereby, a gradual transition from the large cross section of the opening in the piston to the small cross section of the tubule or vice versa is provided for. By this flow enhancing configuration the risk of an haemolysis is again reduced.

In order to accomplish a satisfactory guiding of the piston and the piston rod in the tube and in order to prevent a cocking, it is furthermore proposed to provide at least three guide wings extending radially outwardly from the piston rod and extending in the longitudinal direction thereof, said guide wings with their outer edges extending parallel to one another and to the longitudinal axis of the piston rod and defining an enveloping cylinder which corresponds to the inner peripheral wall of the tube. The piston can now be formed as a simple circular disc, and an excellent guiding and sealing effect is accomplished in particular in case the piston, the piston rod and the guide wings are made of a resilient plastic. The tube can be made in a manner known per se either of glass or of a plastic.

According to this invention a plug of resilient material is associated to the tube, said plug having a knob and an adapter portion adjacent thereto which has a peripheral surface sealingly fitting into the cylinder and a tapered axial bore adapted to the tapered socket of the plunger, said axial bore being closed at its inner reduced end. This plug is formed in such a way that it greatly facilitates the manipulation of the device. Devices of this type are supplied with an inserted plunger and packed sterile. In order to prevent a defilement of the bore of the plunger prior to applying a sterile injection needle, a cap can be applied to this socket. Also a plug is required after the exctraction of blood for closing the tube, after the plunger together with the injection needle has been removed out of the tube. The plug of this invention now combines this cap and the closure plug in a single member. The plug thus with its tapered axial bore initially plugs the socket at the free end of the plunger and later after the removal of the plunger from the tube plugs this tube with its larger adapter portion.

In order to improve the sealing effect, the peripheral surface of the adapter portion is formed slightly tapered. Preferably an annular bead projects radially outwardly from the peripheral surface of the adapter portion which likewise improves the sealing effect. Alternatingly, a plurality of annular beads may be provided also.

The tapered bore at one end of the plug is preferably defined by a hat-shaped recess extending axially inwardly. Then the plug otherwise can be formed generally hollow so that its weight and thus also its price can be kept low.

Depending on whether the blood extracted from a patient is to coagulate and then its constituents are to be examined further or whether the blood is supposed to be centrifugalized without coagulating, it is filled in present day practice from the extraction device into a centrifuge tube or some other container. With the device of this invention the centrifugalizing or also the coagulation process can now be effected in the same tube in which the socket is disposed with the applied injection needle after the removal of this socket.

In order to separate as satisfactorily as possible the two fractions of the blood forming upon centrifugalizing or upon coagulating, the device according to this invention has been developed further in such a way that a chemically inert granulate is added to the tube as a separating agent. This granulate thus is contained in the device packaged sterile comprising the tube and the socket pushed thereinto.

The separating agent assumes a position between the two fractions in the later separation of the blood, be it during coagulation, be it also during centrifugalizing, thus facilitating the examination of one of these two parts alone. The advantage of the combination of the tube with the socket and the separating agent is that thereby a complete device is provided ready for use and that thereby the servicing is extremely facilitated, in particular a refilling is rendered superfluous.

Prior to using the device, it is preferably sterilized inclusive the separating agent and packaged sterile.

When drawing the blood quantity in, it directly encounters the separating agent disposed in the bottom area of the tube.

The granulate filled into the tube preferably comprises a plastic the specific weight of which is between that of the blood cake and that of the serum, i.e. between the specific weights of the two fractions. As a result thereof the separating agent properly assumes a position between the two constituents and separates them from one another.

Furthermore it is proposed to introduce into the tube of the device for the extraction of blood a granulate of a chemically inert substance, the grains of this granulate being coated with a chemical substance at their surface which either accelerates the blood coagulation or, in case this is desired, retards the blood coagulation. Thus, by using various granulates either immediately an accelerated coagulation can be caused so that the examination of the two fractions can be effected earlier than up to now. But on the other hand any blood coagulation can be prevented from the start on by applying a coagulation retarding substance to the surface of the granulate grains so that the blood extracted immediately contacts this coagulation retarding substance.

By the fact that the said chemical substance is provided in a thin layer on a relatively large surface, namely the overall surface of all grains of the granulate, this substance has a particularly quick effect. Substances which retard or accelerate the blood coagulation, of course, have been known already and have also already been used for this purpose, but not as a coating on a granulate as a vehicle which is directly filled into the device for the extraction of blood. This granulate can also at the same time be provided as a separating agent as mentioned hereinbefore.

According to this invention it is furthermore proposed to not coat the surface of the granulate grains with a chemical substance in a thin layer in order to thereby influence the coagulation of the blood, rather it is proposed, for accelerating the coagulation of the blood, that in the surface proximate layers of the granulate grains small glass particles, preferably glass fibres, are embedded. These glass particles projecting from the surface of the granulate grains have a purely physical effect, by influencing the surface tension at the interface, on the blood coagulation. It has been observed that the blood coagulation proceeds slower in vessels of thermoplastic materials, in particular of polyethylene and polypropylene, than in vessels of glass. In some instances such a delay in the blood coagulation is utterly undesired. Up to now then the use of plastic vessels instead of glass vessels had to be dispensed with, although plastic vessels have many other advantages. The glass particles introduced in the surface of the granulate grains according to this invention now bring about substantially accelerated blood coagulations. By a metered addition of these glass particles or the granulate grains provided with such glass particles the blood coagulation can now be accelerated in any desired way, or the slowing down of the blood coagulation can merely be compensated which results when using tubes of plastic, so that thereby blood coagulation ratings are obtained like they result in glass tubes.

Provisions are thus available with these granulate grains including embedded glass particles to arbitrarily accelerate the blood coagulation without having to use chemical substances which perhaps might interfere specific tests.

It is essential for the effect of the granulate proposed according to this invention that the glass particles project from the surface of the granulate grain carrying them without themselves being encased and covered by the substance of the granulate.

A plastic granulate of a conventional grain size is particularly suited for this purpose like it is used for charging plastic processing machines, for instance extruders. Basically all plastics are suited for this provided they are not objectionable for chemical reasons and interfere the blood examination. Fine glass particles, for instance short fibres of glass, are then to be included in the individual grains of the granulate. Such plastic granulates or intermediate products of plastic which are enforced by glass fibres or glass particles are known already. They are suited as an aid for the examination of blood in the sense of the invention only in the event the glass particles, for instance the ends of the glass fibres, project outwardly from the surface of the plastic particles and thus become physically effective. It is to be observed when producing such granulates that the glass particles or at least some of them project outwardly from the surface.

This invention is explained hereinafter in embodiments in referring to the drawing. Therein:

FIG. 1 is a longitudinal sectional view of the device of this invention;

FIG. 2 is an enlarged cross sectional view along the line II-II in FIG. 1;

FIG. 3 is a sectional view of a modified device with an eccentric duct, in a section along line III--III of FIG. 4;

FIG. 4 is a sectional view along line IV-IV of FIG 3;

FIG. 5 is a device similar to the device illustrated in FIG. 1, in a side elevation of view, with applied plug;

FIG. 6 is a sectional view of the plug in FIG. 5 and of the conical socket of the plunger;

FIG. 7 is a sectional view along line VII--VII of FIG. 6;

FIG. 8 is a sectional view of the plug as illustrated in FIG. 6, but inserted in the end of the tube;

FIG. 9 is a simplified sectional view of a tube of the device in the filled condition; and

FIG. 10 is a sectional view in an enlarged scale of a granulate particle with embedded glass fibres.

The device illustrated in FIG. 1 comprises a tube 1 closed at one side, a socket inserted therein, which includes a tubular piston rod 2, four lateral guide wings 3 and at their lower end a disc-shaped piston 4, two radially outwardly projecting handles 5 which are to facilitate the manipulation of the device, and a connecting socket 7 for applying the cap 8 of an injection needle 9. The piston 4, the tubular piston rod 2, the guide wings 3, the connecting socket 7 and the handles 5 are made in one piece and preferably of a resilient plastic, for instance polypropylene.

The tube can be made in a conventional way of glass or also of a plastic, for instance of polystyrene.

As will be noted from FIG. 2, the guide wings 3 closely engage the inner peripheral wall of the tube 1 with their outer edges and thereby guide the piston properly in the tube.

The modified embodiment illustrated in FIGS. 3 and 4 of the blood extraction device again includes a tube 101 closed at one side, a plunger 102 shiftable in a hermetically sealing fashion in this tube, a tubular plunger rod 103 connected thereto and at the end thereof a handle 109 as well as a connecting socket 110 for applying an injection needle.

The piston comprises a thin circular disc 111 which may possibly slightly deviate from the circular shape in manufacture, and a thin circular cylindrical collar 112 projecting from the periphery thereof in axial direction, said collar taking over the sealing function in relationship to the tube 101.

The bore 104 through the circular disc 111 and the plunger rod 103 connected thereto are arranged concentrical in relationship to the central axis of the tube 101. Accordingly the connecting socket 110 for applying an injection needle also is disposed relatively closed to the circumference of the tube 101.

Guide wings 105, 106, 107 and 108 extend from the plunger rod 103 outwardly to the inner wall of the tube. These veins have different lengths because of the eccentric position of the plunger rod.

In the device illustrated in FIG. 5 a plug 10 is disposed on the connecting socket 7a and has a knob 12 which at the outside is provided with corrugations or the like. An adapter portion 11 is provided axially adjacent to the knob and has a radially projecting narrow annular bead 14.

Otherwise the device according to FIG. 5 again comprises a tube 1a, a tubular piston rod 2a with guide wings 3a and handles 5a as well as a disc-shaped piston 4a at the free end of the piston rod 2a. The connecting socket 7a serves to apply the cap of an injection needle when preparing the device for use.

It will be noted from the sectional view of FIG. 6 that the plug 10 is formed generally hollow and has a conical inverted portion 15 setting out from the bottom of the adapter portion 11. This inverted portion has an inner conical peripheral surface which is adapted to the conical outer peripheral surface of the socket 7a of the plunger. With the plug applied thus the longitudinal bore 6a of the plunger and of the socket 7a is covered and closed by the hat-shaped inverted portion 15.

As will be noted from FIG. 6 in conjunction with FIG. 7, the comparatively thin walls of the knob 12 of the plug are supported by four radial walls 13 which at their lower or inner end, as will be noted from FIG. 6, are connected to the closed end of the inverted portion 15 and thereby are also supported in relationship to this inverted portion. Thereby a great increasing of the strength of the plug is accomplished even with a thinwalled configuration. On the other hand the thin-walled configuration facilitates the sealing in the vicinity of the annular bead 14 of the adapter portion 11.

A granulate 16 of plastic, acting as a separating agent, is filled into the tube 1a.

The sectional view of FIG. 8 shows how the adapter portion 11 of the plug is inserted in the upper opening of the tube 1a and how the annular bead 14 in doing so causes a reliable sealing effect. It will be noted that the adapter portion 11 is radially offset at the junction to the knob 12 relative thereto. The shoulder defined thereby serves as an abutment when inserting the plug in the tube 1a.

In FIG. 9 finally the tube 1b of a device of this invention has been illustrated filled with a blood sample. The figure shows the blood sample after centrifugalizing. In the lower portion of the tube the sedimented blood-corpuscles 19 are disposed, thereabove the separating layer 18, comprising the granulate acting as a separating agent, which at its surface was coated with a substance retarding the blood coagulation, thereabove the liquid plasma 17.

The same picture virtually results when the blood is caused to coagulate and the blood is then centrifugalized. Then the coagulated blood cake is disposed at the bottom of the tube, thereabove the separating agent layer and thereabove the liquid serum. In this case preferably a separating agent is used with a chemical substance for accelerating the blood coagulation or with embedded glass particles which have the same effect. Various chemical substances are known which chemically have an effect on the blood coagulation process and accelerate it.

But it also known that the blood coagulation can be influenced by physical means. For instance blood coagulates slower in vessels of thermoplastic materials than in vessels of glass, which is to be explained by the different surface tension and the physical conditions at the interface between the blood and the container wall.

In furtherance of the invention it is not proposed that the substance accelerating the blood coagulation and disposed on the top surface of the granulate grains is glass, namely in the form of fine particles, in particular fibres, which are embedded in the outer layer of each granulate grain. Principally all plastics are suited for such a granulate, provided they do not interfere with the blood examination for chemical reasons. The glass fibres are to project outwardly from the surface of the plastic parts, in order to become physically effective therewith. In FIG. 10 such a granulate particle 20 has been illustrated to an enlarged scale, namely in cross section to the left side of the section line A--A and in a elevation of view at the right hand of this line. The glass fibres 21 embedded irregularly in the granulate particles 20 will be noted which project from the surface of the granulate particle 20.

Claims

What is claimed is:

1. A device for the extraction of blood by means of a suction effect comprising a tube having a closed end and an open end, a one-piece piston assembly cooperatively telescoped within said tube, said piston assembly comprising a piston having an aperture therethrough, a hollow piston rod extending from said piston in communication with the aperture therein and extending out through said tube open end, said piston being in sealed engagement with the interior of said tube and said piston rod having axially elongated generally radially extending wings guidedly engaging the interior of said tube, said piston rod having a free end in the form of means for the reception of a needle in sealed engagement, a transversely disposed handle on said piston rod adjacent said free end for withdrawing said piston assembly from said tube to produce a suction within said piston rod, said hollow piston rod has a tapered bore, said bore decreasing in cross section from said piston towards said free end whereby a maximum suction is effected at said piston rod free end.

2. A device for the extraction of blood by means of a suction effect comprising a tube having a closed end and an open end, a one-piece piston assembly cooperatively telescoped within said tube, said piston assembly comprising a piston having an aperture therethrough, a hollow piston rod extending from said piston in communication with the aperture therein and extending out through said tube open end, said piston being in sealed engagement with the interior of said tube and said piston rod having axially elongated generally radially extending wings guidedly engaging the interior of said tube, said piston rod having a free end in the form of means for the reception of a needle in sealed engagement, a transversely disposed handle on said piston rod adjacent said free end for withdrawing said piston assembly from said tube to produce a suction within said piston rod, said hollow piston rod is tapered from said piston to said free end, and said piston rod has a similarly tapered bore whereby a maximum strength to weight ratio is obtained together with a maximum suction being effected at said piston rod free end.

3. A device for the extraction of blood by means of a suction effect comprising a tube having a closed end and an open end, a one-piece piston assembly cooperatively telescoped within said tube, said piston assembly comprising a piston having an aperture therethrough, a hollow piston road extending from said piston in communication with the aperture therein and extending out through said tube open end, said piston being in sealed engagement with the interior of said tube and said piston rod having axially elongated generally radially extending wings guidedly engaging the interior of said tube, said piston rod having a free end in the form of means for the reception of a needle in sealed engagement, a transversely disposed handle on said piston rod adjacent said free end for withdrawing said piston assembly from said tube to produce a suction within said piston rod, a plug of resilient plastic, said plug having a knob and an adapter portion axially adjacent thereto, said adapter portion having a peripheral surface sealingly engageable with said tube and a conical axial bore receiving said piston rod free end, said axial bore being closed at its inner end.

4. Device according to claim 3, characterized in that at least one annular bead projects radially outwardly from the peripheral surface of the adapter portion.

5. Device according to claim 3, characterized in that the conical bore is defined by a hat-shaped inverted portion extending from the free end of the adapter portion axially inwardly.

6. A device for the extraction of blood by means of a suction effect comprising a tube having a closed end and an open end, a one-piece piston assembly cooperatively telescoped within said tube, said piston assembly comprising a piston having an aperture therethrough, a hollow piston rod extending from said piston in communication with the aperture therein and extending out through said tube open end, said piston being in sealed engagement with the interior of said tube and said piston rod having axially elongated generally radially extending wings guidedly engaging the interior of said tube, said piston rod having a free end in the form of means for the reception of a needle in sealed engagement, a transversely disposed handle on said piston rod adjacent said free end for withdrawing said piston assembly from said tube to produce a suction within said piston rod, a granulate in said tube between said piston and said tube closed end, said granulate being a chemically inert substance for functioning as a separating agent between two blood fractions, and including surface proximate layers with embedded small glass particles, preferably fibres, partially projecting outwardly from the surface thereof.

7. A device for the extraction of blood by means of a suction effect comprising a tube having a closed end and an open end, a one-piece piston assembly cooperatively telescoped within said tube, said piston assembly comprising a piston having an aperture therethrough, a hollow piston rod extending from said piston in communication with the aperture therein and extending out through said tube open end, said piston being in sealed engagement with the interior of said tube and said piston rod having axially elongated generally radially extending wings guidedly engaging the interior of said tube, said piston rod having a free end in the form of means for the reception of a needle in sealed engagement, a transversely disposed handle on said piston rod adjacent, said free end for withdrawing said piston assembly from said tube to produce a suction within said piston rod, a granulate in said tube between said piston and said tube closed end, said granulate being a chemically inert substance for functioning as a separating agent between two blood fractions, and the particles of said granulate having a coating of a substance for retarding blood coagulation.

8. A device for the extraction of blood by means of a suction effect, said device comprising a tube having a closed end and an open end, a one piece integrally molded piston assembly cooperatively telescoped within said tube, said piston assembly comprising an inverted cup shaped piston, a tubular rod, axially extending guides, and handle means; said cup shaped piston having a cylindrical portion in sliding sealed engagement with said tube and an end wall, said tubular piston rod being carried by said piston end wall in eccentric relation to said piston and tube and projecting out of said tube, said piston rod having a free end, means only at said free end for the mounting of a needle thereon, said axially extending guides projecting generally radially from said piston rod and guidedly engaging said tube, at least two of said buides being of appreciably different radial dimensions due to the eccentricity of said piston rod relative to said tube, a bore in said piston end wall in communication with the interior of said piston rod, and said handle means on said piston rod being adjacent said free end.

9. A device for the extraction of blood by means of a suction effect, said device comprising a tube having a closed end and an open end, a piston assembly cooperatively telescoped within said tube, said piston assembly comprising an inverted cup shaped piston having a cylindrical portion in sliding sealed engagement with said tube and an end wall, a tubular piston rod carried by said piston end wall in eccentric relation to said piston and tube and projecting out of said tube, said piston rod having a free end portion defining means for the mounting of a needle axially extending guides projecting generally radially from said piston rod and guidedly engaging said tube, a bore in said piston end wall in communication with the interior of said piston rod, handle means on said piston rod adjacent said free end, said piston rod is conically reducing in cross section from said piston toward said free end whereby at least two of said guides taper in opposite directions relative to each other and to the length of said piston rod.