Blood Collector Device

Abstract

A tube for use in the automatic collection of a digital blood sample has its mouth fitted with a resilient detachable funnel member which can carry a capillary cannula and in which is held an absorbent annular plug through which pass and project two incisor lancets.

Description

This invention relates to a device for collecting a percutaneous blood sample.

There are various known methods for obtaining a percutaneous blood sample, and in particular a digital sample.

In one of these, the area of the finger from which blood is to be withdrawn is first disinfected and the skin is then pricked to a depth of about 2 or 3 mm. The first drop of blood issuing from the incision is removed since this contains a relatively substantial quantity of blood originating from the subcutaneous cells and the finger is then massaged in the direction of the incision. The blood obtained during this massage is collected in a test tube, in a capillary tube, or by suction into a tube.

These different stages in the taking of a blood sample are usually carried out by qualified personnel who are now becoming more and more scarce.

It is therefore evident that considerable advantages would ensue from the provision of apparatus permitting a blood sample to be taken automatically by the subject and without the necessity of any intervention by a specialist personnel.

An object of the invention is to contribute to the creation of such apparatus and with this object in mind, the invention provides a device for collecting a percutaneous digital blood sample, comprising a tubular body closed at one end and adapted to collect the blood, a funnel member of resilient material engaged at its discharge end in the mouth of said body and supported by an annular zone of its lateral surface on the rim of said mouth, a mass of absorbent material located within the discharge end of the funnel member, and at least one incisor lancet projecting through and beyond said mass and located wholly within said funnel member.

In the accompanying diagrammatic drawings:

FIG. 1 is a sectional elevation of a first form of embodiment;

FIG. 2 is a similar view showing the method of making an incision;

FIG. 3 is a perspective view of a detail of FIG. 1;

FIG. 4 is a sectional elevation of a second embodiment; FIG. 5 is a sectional elevation of a third embodiment;

FIG. 6 is a part view of the tube used in FIG. 5 filled with blood;

FIGS. 7 and 8 show two different constructional forms for the tube used in FIG. 5;

FIG. 9 is a sectional elevation of a fourth embodiment; and

FIGS. 10 to 13 are diagrammatic sectional views, in different operating positions, of various parts of an automatic blood sampling apparatus making use of a device of the kind shown in FIGS. 1 to 9.

The device shown in FIG. 1 of the drawing comprises a tubular body 1 of a transparent or translucent material, for example, polyethylene, in the mouth of which is engaged a plug 2 constituting the lower, discharge, part of a funnel member 3 having a cuplike portion 4 of resilient plastics material. The cup 4 rests on the rim of the mouth of the tubular body 1 by means of an annulus 4a provided at the base of the cup 4. The wall of the cup 4 and the plug 2 are formed with an L-shaped groove 5 forming a passage which allows air to escape as the tubular body 1 is being filled with blood.

At the lower end of plug 2 there projects a capillary cannula 6 extending nearly to the bottom of the body 1, coaxial with said body and forming an extension of an axial passage in the plug 2.

At the bottom of the cup 4 is provided an annular groove 4b in which is held the peripheral part of a circular metal plate 7 (FIGS. 1 and 3), for example of stainless steel, which is provided with two triangular lancets 8a and 8b made of the same metal and extending perpendicularly to the plate 7 on opposite sides of a slot 9 in said plate.

Above the plate 7 in the cup 4 is arranged an annular pad 10 of absorbent material, for example, blotting paper, and held in position by the lancets 8a and 8b. As shown, the slot 9 and the opening in the pad 10 are in alignment with the passage in plug 2.

The part of the lancets 8a and 8b that projects above the pad 10 has a length of at least 2 to 3 mm.; these lancets may extend further but not beyond the level of the upper rim of cup 4.

The lancets 8a and 8b are intended to form the cutaneous incisions that have to be made for taking a blood sample (FIG. 2) and it is clearly necessary that these incisions should be sufficiently deep to reach blood vessels of some importance. The actual procedure for obtaining a blood sample will be described below with reference to FIGS. 10 to 13.

The device shown in FIG. 5 differs from that shown in FIG. 1, firstly in that the plug 2 of the funnel member 3 does not carry a cannula 6, and secondly in that the air in the tubular body 1 is discharged through a passage 11 formed in and coaxially with the base of the body 1. This passage 11 passes through a tubular element 12 which is integral with the body 1 and around which is arranged a metal ring 13. The element 12 is, like the body 1, of plastics material, for example, polyethylene, and is intended to act as a closure member for the passage 11 when its wall is crushed by means of the ring 13 which can be tightened as by crimping (FIG. 6).

By way of modification, when the body 1 or at least part of the tubular element 12 is of thermoplastic material, the passage 11 can be closed off by partial fusion of the element 12 (FIG. 7).

If, on the other hand, the body 1 is made of a plastics or other material having a high fusion point and low elasticity, the passage 11 can be closed off by the insertion of a simple stopper 13A (FIG. 8), preferably of compressible material.

The FIG. 9 embodiment differs from that shown in FIG. 1 or FIG. 4, in that the lancets, here identified 14a and 14b, that are provided in the cup 4 are integral with the upper end of the cannula here identified 15, which cannula is engaged in the axial passage of plug 2, the lancets and the cannula 15 forming a single metallic body, for example of stainless steel.

FIGS. 10 to 13 illustrate one form of automatic blood sampling apparatus making use of the kind of device shown in FIGS. 1 to 9.

This apparatus comprises a casing 16 of rectangular section in the upper left hand part of which, as seen in FIG. 10, is pivotably mounted at 17 a lever 18 having two parallel arms 18a of which only one can be seen, connected together by a common part 18b covered on its internal surface with a pad of synthetic sponge 19, each arm 18a extending through a slot 16a provided in the left hand face and the upper face of casing 16.

The free end of each arm 18a of lever 18 is formed with teeth 20 for holding the lever down when it is swung over into the position shown in FIG. 12, this holding down action being effected in cooperation with a pawl 21 subjected to the action of a spring 22 which tends to hold it in engagement with the teeth 20 of lever 18 but which can be counteracted by a relay 23 adapted, when energized, to rock the pawl 21 in a clockwise direction to free the lever 18. The latter is permanently subjected to the action of a spring 24 tending to swing it back to the raised position of FIG. 10.

The lever 18 is also provided with a beak 18c intended to cock a striker device comprising a striker lever 25 pivotably mounted at 26 on a lug 27 formed on a support 28 fixed to the base of the casing 16. The lengths of beak 18c and lever 25 and the positions of their pivotal points are such that the paths of the tip of beak 18c and the tip of lever 25 intersect one another over a defined length.

Levers 25 bears on the head 29 of a push-piece 30 subjected to the action of a spring 31 and slidably mounted in a hole formed in the support 28, this push-piece being further provided at its lower end with a stop 30a which limits its possible axial displacement in the direction of lever 27.

Above lever 27 and in the mean swinging plane of lever 18, the casing 16 has a tubular member 32 orientated coaxially with the push-piece 30 and opening at the level of the upper face of the casing, the diameter of this member being slightly greater than the external diameter of the tubular body of a blood-collecting device E of the kind shown in FIGS. 1 to 9. During the taking of a blood sample this member 32 acts as a holder and guide member for the device E.

Between the tubular member 32 and the slot 16a, the apparatus casing 16 carries a fixed block 33 of trapezoidal section and acting as an aid for correctly positioning on the apparatus a finger from which a blood sample is to be taken.

On the same face of the apparatus casing 16, on the side of member 32 opposite block 33, there projects, through a slot 16b, a massaging block 34 mounted at the end of a lever 35 pivoted at 36 on a link 37 rigid with a shaft 38 which by means of a motor (not shown) can be rotatably driven in an anticlockwise direction as seen in the drawing. As shown in FIG. 11, the position of the block 34 on the casing is such that when the subject from whom a blood sample is to be taken places one of his fingers on the block 33 and lever 18 has been swung down, the pad 19 of lever 18 comes to bear on the part of the finger opposite block 34.

When a blood sample is about to be taken, the various parts of the apparatus described occupy the positions shown in FIG. 10.

A blood collector device E is then placed within the tubular member 32 and pushed until its funnel member is flush with the upper opening of said member.

The subject then lays his hand on the upper face of casing 16 and places the finger to be bled on the massage block 34 with the tip of the finger against the locating block 33 in such a way that the distal part of the finger underlying the nail rests on the rim of the funnel member, as shown in FIG. 11. The area of the finger where the incisions are to be made will, of course, have been previously cleaned and disinfected in an appropriate manner.

All that is then required is to swing lever 18 downwards to bring it into the locked position shown in FIGS. 12 and 13 in order for the necessary incisions to be made in the epidermis of the finger from which a blood sample has to be taken, since this movement of lever 18 causes the beak 18c to bear on lever 25, thereby depressing the latter to compress spring 31, this cooperation between beak 18c and lever 25 continuing as long as the curvilinear paths of their tips intersect one another (FIG. 11).

When these two paths cease to intersect, lever 25 is freed from engagement with beak 18c and then suddenly finds itself subjected to the sole action of the compressed spring 31 which pushes it abruptly against the base of the tubular body of the blood collector device E (FIG. 12).

This body is then correspondingly pushed in the direction of the finger, causing it to slide within the tubular member 32 and to deform the cup 4 of the funnel member 3 (FIG. 2) on which the finger tip bears, and hence to drive the lancets 8a and 8b into the latter to produce the required incisions of the epidermis and dermis.

As soon as the kinetic energy communicated to the tubular body of the blood collector device by percussion has been dissipated, partly by deformation of cup 4 and partly by the formation of the incision, the tubular body of the blood collector device is urged back to the lowered position shown in FIG. 13 under the action of the cup 4 which acts as a resilient return member upon resuming its original shape. As the tips of the lancets extend at most to the level of the rim of cup 4 when the latter is not deformed, the lancets will clearly be completely withdrawn from the incisions they have made when the cup resumes its position of rest so that it is then possible to proceed to collect a blood sample without the subject feeling any impediment or pain.

To obtain a blood sample, shaft 38 is set in rotation and this rotation imparts an eccentric movement to lever 35 and consequently an undulatory movement to the massage block 34, alternately towards the stationary block 33 during an ascending phase and in the opposite direction during a descending phase (FIG. 13).

As the finger of the subject is gripped between the pad 19 and the block 34, this undulatory movement of the block 34 can only take place by cyclically compressing the underside of the finger from the rear towards the front thereby performing a massage of the digital tissue and hence a periodic flow of blood towards the percutaneous incisions.

The blood issuing from these incisions flows first into cup 4 (FIG. 1) and then through cannula 6 into the tubular body 1, the air in this body escaping through groove 5 as filling proceeds.

It is to be noted that the first few drops of blood entering the cup are not collected in the tubular body 1 but are absorbed by the absorbent paper pad 10, as these drops of blood contain a very high proportion of physiological liquid which originates from the subcutaneous cells and which is clearly undesirable in a blood sample.

Thus it is only when the pad 10 has been sufficiently impregnated with a mixture of physiological liquid and blood, that the blood issuing from the finger will be more suitable for sampling and it is this blood that will flow into the tubular body 1. In this connection it is to be noted that the lancets considerably facilitate this flow because, although removed from the epidermis they lie directly opposite the incisions and are at a very short distance from them so that the drops of blood issuing from the incisions fall on and are ruptured by the tips of the lancets and then flow rapidly over the surface of the latter into the cannula 6. The lancets thus play the part of effective collectors preventing the formation of a thick blood dispersion in the cup 4.

The massage performed by the movement of the block 4 is, of course, interrupted when the blood in the tubular body 1 reaches a desired level.

At that point the relay 23 is energized to release lever 18 which then frees the finger. The filled blood collector device E is then manually removed from the tubular member 32, whereupon the funnel member 3 and associated cannula 6 are removed from the tubular body 1. The latter is then closed by a suitable stopper in order to prevent coagulation of the blood collected, in particular when it is not to be subjected to an immediate examination.

Claims

We claim:

1. A device for collecting a percutaneous digital blood sample comprising a tubular body fixedly closed at one end and open at the other end and adapted to collect the blood, a funnel member having a resilient funnel portion and a discharge end comprising an annular portion with a passage therethrough and engaged at its discharge end in the open end of said body and supported by an annular zone of its lateral surface on the rim of said open end, a mass of absorbent material located within said funnel portion, and at least one incisor lancet in said funnel portion projecting through and beyond said mass and located wholly within said funnel member and means associated with said funnel member to allow air entrapped within said body to vent.

2. A device according to claim 1, and including a capillary tube forming an extension of said annular portion and extending to a location adjacent the closed end of the tubular body.

3. A device according to claim 2, wherein one end of the capillary tube is located within the passage in said annular portion, and is integral with said lancet.

4. A device according to claim 2, wherein the capillary tube is integral with the funnel portion.

5. A device according to claim 1 and including a base plate supported in a lower part of said funnel portion, the lancet being integral with said base plate.

6. A device according to claim 1, wherein the means for allowing entrapped air to vent comprises a passage located in a lower part of the body and communicating with a tubular element integral with said lower part and projecting beyond said part, said device further comprising a closure means for closing said element.

7. A device according to claim 1, wherein the funnel member is secured in a fluidtight manner within the open end of the tubular body and said means for allowing air to vent comprising a passage located in the periphery of said annular portion and the base of said funnel portion.

8. A device as in claim 1 wherein said annular portion is constructed of resilient material and is integral with said funnel portion.