Blood sampling device with a canule incorporating holder

The present invention relates to a blood collection device with a cannula containing holder.

A blood-collecting device with a handle is known from U.S. Patent No. 3,589,984, which includes a cannula shaped with a sharpened cutting edge in the form of a hollow needle. The cannula is wrapped around a closed, tubular valve with air between the cannula and the elastic. The handle has a domed cap protruding from the front, into which the thickened head or plug, which is one part with a valve rubber, sinks. This head is a segment that fixes the valve rubber from the outside of its outer shell. The valve rubber band in the front part, i.e. its thickened head, slips tightly onto the cannula and thanks to the friction force it is fixed from the inside towards the cannula and from the outside towards the handle.

The blood-collecting device known from DE-C 18 12 742 uses a single-sided open tubular handle, which has a sharpened cutting edge formed at both ends, having the form of a hollow needle, a double cannula, the rear end of which also enters the handle as a guide bushing. While the rear end of the double-pointed hollow needle is surrounded by an elastic valve band and is wrapped in air, the front end of the cannula protrudes from the front wall of the handle and serves to insert into the patient's vein. The collected blood enters the tube, which was previously connected to the handle from the open end. When connecting the handle to the blood collection tube, the cutting edge of the rear end of the cannula first penetrates through the proximal wall or bottom of the flexible valve rubber band and then the flexible stopper of the blood collection tube, so that finally the rear end of the cannula enters the tube; the elastic band is pressed like a harmonica. After collecting blood and removing the tube from the holder, the valve rubber band automatically adopts its initial position, sealing the posterior end of the cannula. The holder could alternatively be reduced to one disc containing the cannula, i.e. there need not be a guide sleeve. Then the gripping disk could be connected to the cap of the blood collection tube.

DE-U 80 16 927 describes another embodiment of a double-cannula shaped blood sampling device. when taking blood. The cannula consists of a one-sided, open, cylindrical housing with an outer cone formed in one part and a cut-out cannula located on it, constituting essentially its rear end. A clamping cone of the handle with a one-sided pointed cannula or a hollow needle is attached to the outer cone, so that when the two parts are joined, a double cannula is formed, as already described above. With this needle variation, it is possible to connect a regular Luer cannula to a blood collection tube. The valve rubber also found here adheres closely to the hollow needle of the handle or fitting. Within the scope of possible applications it is possible to couple such a connector with a Luer cone through a special connection with e.g. a blood-filled hose.

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In the DE-A 29 03 167 safety cannula known from the description of multiple applications, for repeated blood collection, the flexible valve rubber that slides harmonically when connected to the blood collection tube is again placed with surrounding air or radial play at the rear end of the double cannula, i.e. valve along its entire length has an outer diameter larger than the outer diameter of a cannula or hollow needle.

The valve band around the blood collection device, the rear end of the cannula allows filling of several blood collection tubes by coupling with the double cannula. In the case of a valve rubber fitting closely to the hollow needle (cf. DE-U 80 16 927) an unavoidable friction occurs between the needle and the eraser, which causes the eraser to retract too slowly from the accordion into the relaxed starting position; therefore, in these cases the flow of blood from the cannula cannot often be avoided when replacing the blood collection tubes. This is because a rubber band cannot close the rear end of a pointed double cannula fairly quickly. This is avoided when the flexible, serpentine valve rubber is at a certain radial distance from the needle, i.e. the latter is surrounded by air (see DE-A 29 03 167 and DE-C l8 12 742). However, because the valve rubber does not adhere tightly to the needle, there is a problem with stabilizing this rubber in the handle or fitting. Therefore, the valve elastic band in the DE-C 18 12 742 blood sampling device is formed at its open end with a thrust ring, which adheres to the inner shoulder of the handle, and thus thanks to the friction between the skirt side surface and the inner shell of the handle the position stabilizes. The valve rubber band known from DE-A 29 03 167 the double cannula is formed at its open rear end with an outer ring which is inserted into the annular groove of the handle's end wall. Apart from the fact that here also the valve rubber is loosely seated in the handle, its installation is difficult and requires great dexterity when introducing the flexible valve rubber into the annular groove.

In addition, other techniques for mounting the rubber band are known, e.g., shape-clamp sliding of the band on the cylindrical segment in the middle of the cannula (see German application DE-A 37 40 269). From the European application EP-A 0 619 096 it is known that the valve elastic in its front part has to be slipped over the edge upset, while the publication WO-A 95/16395 teaches that the valve elastic must be rolled up on the circumferential conical wreath with undercuts and possibly still glued there . According to the European application EP-A 0 678 279, the valve rubber is attached to the perimeter flange on the peripheral rim inside the handle and secured with a plastic insert

The invention is based on the task of creating a type of blood-collecting device of the type specified at the outset, which, with low labor intensity of assembly, allows the valve rubber to be firmly seated in the handle or fitting.

This task is solved in accordance with the invention in that the handle segment fixing the valve rubber from its outside is in the form of a deformable clamping element. As a result, the valve rubber is no longer placed loosely or by friction in the holder or by gluing, but is fixed reliably by means of the deformable clamping element according to the invention; it can no longer be pulled off the cannula or fall out of the holder. At the same time, it is guaranteed that there is a radial gap between the valve band and the needle or the rear end of the double cannula, so that there is no friction between these two parts and the elasticity of the valve band can be ensured to immediately close the rear end of the cannula when replacing the tube blood collection; blood flow is therefore avoided at this point. When manufacturing a valve rubber, it is not necessary to maintain contours and tolerances, nor are any special seals on the inner coating of the valve rubber.

The invention in an embodiment is shown in the drawing showing a blood sampling device which has a handle 1 open on one side, in which the front wall 2 is fitted with a double cannula 3, for example by welding or gluing, which makes it possible to dispense with an additional needle holder. The double cannula 3 has front and rear bevelled edge 4 and rear 5. The rear end of the cannula 6 goes into the sleeve

185 564 guide 7 of the handle 1, while the front end of the cannula 8 protrudes from the handle 1 and is inserted into the vein of the patient for blood collection. For blood collection, the sleeve 7 slides in a known manner onto a suitable blood collection tube, where the bevelled edge 5 of the rear end of the cannula 6 penetrates both the bottom 9 of the rubber band 11 that wraps at a radial distance 10 the rear end of the cannula 6 as well as the flexible plug not shown drawing the blood collection tube until it connects to the inside of the tube.

The flexible hose-shaped rubber band 11 has been inserted with its open end opposite the bottom 9, into a clamping element 12 shaped concentrically to the guide sleeve 7 in the holder 1 on the inside of the front wall 2. The clamping element 12 may be, for example, a circumferentially closed ring or ring of separated segments which, or which, after plugging in the rubber band, adheres to the outer shell 13 of the rubber band 11, deforming and clamping the rubber band 11 under pressure shown in the lower half of the figure, where reference numeral 12 denotes the deformed clamping element. Thus, the open end of the rubber 11 is sufficient to push on the inside of the front wall 2 into the annular gap in the clamping element 12 and it is reliably fixed in the holder 1 after deformation of one or more clamping elements.

The clamping element or its individual segments can be deformed, for example, by means of a piston, which has a hole at the rear end of the cannula 6 together with a circulating valve rubber band 11. When the front part of the hole is tapered and has a larger diameter than the sleeve clamping element 12 or the individual segments to be clamped are clamped by the conical part of the hole against the outer shell 13 of the rubber 11 with the axial movement of the piston (cf. reference 12 'in the figure). After removing the piston, the clamping element 12 remains in this position and reliably fixes the valve rubber 11 in the handle 1.

Alternatively, the various types of grips described at the outset can also be used, the grip may also optionally be formed as one part with the cannula.

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UP Department of Publications. Circulation of 60 copies

Price PLN 2.00