Dual lumen needle for withdrawal of body fluids.

(42) Date of commencement of the patent: 15.12.1993 (45) Date of issue: 25. 8.1994

<td>(56) Documents:</td><td>(73) Patent owner:</td>

<td>EP-A1 0000041 EP-A1 0107810 EP-A2 0191599 EP-A2 0243341 WO 88/05643</td><td>AVL COMPANY FOR INTERNAL COMBUSTION ENGINES AND MEASUREMENT TECHNOLOGY MBH. PROF.DR.DR.HC HANS LIST A-8020 GRAZ, STEIERMARK (AT).</td>

<td></td><td>(72) Inventor:</td>

<td></td><td>SKRABAL FALKO DR. GRAZ, STYRIA (AT). KLEINHAPPL ERICH ING. WEINITZEN, STYRIA (AT).</td>

(54) TWO-PIECE BODY LIQUID UNLOADING NEEDLE (57) To improve comfort and reduce the overall diameter of a bi-lumen body fluid collection needle, for example, blood or tissue fluid, with a first and a second, essentially parallel guided elastic cannula, wherein in the first cannula after insertion of the withdrawal needle removable insertion needle is inserted, whose ground end protrudes beyond the first cannula, is planned in the known manner, the second cannula (12) in the distal end region of the withdrawal needle (1) has at least one connection opening (22, 22 ') to the first cannula (3), and in a known manner, a grip part (8) of the removal needle (1) in addition to terminals (10, 11) for the two cannulas (3, 12) one by an elastic, self-sealing plug (18) closed separate opening for removal of the insertion needle (2), further wherein in the first KanüUJ le (3) inserted insertion needle (2) the second elastic cannula (12) is closed either by the occurred deformation, or whose lumen is narrowed in cross-section approximately crescent-shaped and in the wall of the first cannula at least one opening (5) is provided.

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AT 397 911 wr eerasia

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The invention relates to a two-lumen sampling needle for body fluids, such as blood or

Tissue fluid, having a first and a second, substantially parallel elastic guided

Cannula, wherein in the first cannula after insertion of the withdrawal needle removable insertion needle is inserted, the ground end of which projects beyond the first cannula.

In medicine, there are a number of applications for two-lumen needles, which are always advantageous when a substance is supplied to the body by a lumen and this substance, a reaction product or a body fluid to be removed through the other lumen.

For example, in tissue perfusion, a perfusion fluid is delivered to the tissue via a lumen of a two-lumen needle which, after a brief equilibration phase, is recovered through the other lumen of the needle. The outer wall of the needle has openings to increase the contact area with the tissue.

Thus, for example, WO 88/05643 several variants of two-lobed needles have become known, which consist essentially of two nested steel tubes. Double-steel needles can be made with a relatively small overall diameter, minimizing patient pain, and also provide the necessary strength to pierce the tissue due to the material used. The disadvantage is only the stiffness of the needle, which reduces the comfort during prolonged rest.

From WO 88/05643 is further a catheter or a withdrawal needle made of elastic material known whose inner lumen in cross-section star-shaped projecting septa, wherein the capillary gaps form the bounded by the adjacent tissue outer lumen of the needle. The flexible catheter is located in the puncture in the tissue in a hollow needle, which is withdrawn after piercing, so that only the elastic catheter remains in the tissue. A disadvantage of this embodiment is the enlarged by the hollow needle overall diameter, which increases the Schmerzbeiastung the patient, and the increased manipulation effort.

From EP-A 0 191 599 a two-lumen withdrawal needle of the type mentioned is known, which, however, is only suitable for Diaiysezwecke. The openings of the two lumens are axially as far away from each other as possible in order to prevent that introduced by the Diaiysevorrichtung in a blood vessel blood is immediately sucked back from the second lumen. Furthermore, a certain amount of manipulation is required to connect to the Diaiysevorrichtung after removal of the insertion needle from one of the two cannulas without coming into contact with blood.

The object of the invention is to propose a removal needle of the type mentioned, which combines a small overall diameter with a higher wearing comfort with longer lying time and can also be used for tissue perfusion. Furthermore, the manipulation effort should be reduced and the leakage of body fluids should be prevented.

This object is achieved according to the invention in a known manner, the second cannula has at least one connection opening to the first cannula in the distal end region of the withdrawal needle, and in a known manner, a handle part of the sampling needle in addition to connections for the two cannulas one by an elastic, having self-sealing stopper closed separate opening for removal of the insertion needle, wherein, in addition, when the insertion needle is inserted in the first cannula, the second elastic cannula is closed either by the deformation that has taken place, or whose lumen is narrowed in cross-section approximately crescent-shaped and in the wall of the first cannula at least one opening is provided. Through the connection opening, a flow reversal, for example a perfusion liquid, can already be ensured within the withdrawal needle. As long as the insertion needle is located in the withdrawal needle, the lumen of the second cannula can be deformed into a narrow slot, which unfolds accordingly after the removal of the insertion needle, due to the different pressure conditions in the two cannulas. As a result, the overall diameter of the removal needle can be kept low.

From EP-A1 0 000 041 it is indeed known in this context to provide an elastic, self-sealing plug in the handle of a double-lumen catheter, which has a separate opening for insertion or Removal of the insertion needle closes, however, due to the coaxial arrangement of the cannulas, there is - for a given diameter of the Enfiihmadel - to a larger overall diameter of the sampling needle. Furthermore, this Entnabmenadel in the distal end region on no connection opening between the two lumens.

Although double-lumen catheters or withdrawal needles whose lumens have a connection opening in the distal end region are known, for example, from EP-A1 0 107 810 or EP-A2 Q 243 341, these do not have a removable insertion needle and therefore do not have any through the Insertion needle deformed or narrowed cannula.

AT 397 911 B

The strength required for the piercing of the removal needle according to the invention is determined by the

Insertion needle, for example made of steel, guaranteed, the overall diameter remains small by eliminating an outer hollow needle. After pulling out the insertion needle creates a flexible, elastic, two-lumen withdrawal needle with high comfort.

In a first, extremely user-friendly embodiment of the invention is provided that in a known manner the grip part has a cavity in communication with the first cannula, which by the penetrated by the insertion needle elastic, self-sealing plug is closed, that the grip part has a molding with the connections for the two cannulas, wherein one of the connections opens into the first cannula and into the cavity in the handle part and the other connection is connected to the second cannula and further the cavity in the grip part is adapted via a stepless cone to the inner diameter of the first cannula, and that the second cannula is disposed between the insertion needle and the wall of the first cannula. The insertion of the second, inner cannula in the manufacture of the needle is facilitated by the conical transition.

A further advantageous embodiment of the invention provides that both cannulas are made of plastic in a known manner, wherein the second cannula is integrally formed on the first cannula.

Furthermore, it may be advantageous according to the invention, if in a known manner the Anformung has a hole which opens into the cavity, wherein further into the bore a connector is gas-tight, soft the connections or to the two cannulas leading lines and the connector with the two terminals is preferably secured with a screw on the Anformung of the handle. Above all, it offers a so-called Luer-lock closure.

The removal needle according to the invention is outstandingly suitable for applications in the tissue when the wall of the first cannula has a plurality of wall openings.

Finally, for specific applications of the invention, it is advantageous if the first cannula has a wall opening with a membrane which is selectively permeable to certain constituents of the tissue fluid.

For safe handling of the two-lumen withdrawal needle, the invention proposes that both connections can be introduced into a coupling part with supply and discharge lines in a manner that confuses confusion.

In one-piece design of the double-lumen withdrawal needle is further provided that the at least one connection opening between the first and second cannula is arranged in a partition wall between the two cannulas.

The invention will be explained in more detail below with reference to drawings. 2 shows a variant of the invention, FIGS. 4a and 4b show sections along the line II-II in FIG. 2 and FIG. 5 shows a detail of a further embodiment variant.

The in Fig. 1 Removal needle 1 shown has a Einführnadei 2, for example a steel needle or a metal pin, which of a flexible first cannula 3, eg made of plastic, is tightly enclosed, so that only the ground or pointed or cut-shaped running end 4 of the Einführnadei 2 remains free. The cannula 3 has a plurality of wall openings 5 ​​distributed over the circumference, via which the perfusion fluid comes into contact with the tissue. The Einführnadei 2 is provided on the side remote from the ground end 4 side with a holder 6, which closes a cavity 7 in the handle part 8 of the needle 1. For use in blood vessels withdrawal needles 1 are used, the outer cannula 3 has no openings. In the region of the end 4 of the Einführnadei 2, the cannula 3 can be conically adapted to the diameter of the Einführnadei 2 to ensure a smooth transition.

The second, inner cannula 12 is arranged between the insertion needle 2 and the first, outer cannula 3. By a stepless cone 13 between the cavity 7 and outer cannula 3, the insertion of the inner cannula 12 is facilitated in the manufacture of the needle. In this case, the inner cannula 12 may be deformed and pressed against the inner wall of the outer cannula and unfold its lumen only after pulling out the Einführnadei 2, or lie in a recess in the inner wall of the outer cannula 3. The Griffteit 8 here has a lateral Anformung t6, which receives a connector 9 for ports tO and 11 in a connected to the cavity 7 bore 17. The terminal 10 is directly connected to the second or connected inner cannula 12, soft to just before the end, eventuett to the end of the first or outer canoe 3 is enough. The connection opening between the second and first cannula is designated by 22. The inner cannula could also be a thin metal cannula or a plastic cannula with a steel mandrin. The second port 11 opens into the cavity 7 in the handle part 8 and is thus in communication with the lumen between the inner and outer cannula. The connector 9 is after insertion into the lateral Anformung 16 by a

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Screw 14, preferably a Luer-lock screw, fixed.

However, it is also possible to pour the terminals 10 and 11 directly into the Anformung 16 or

glued.

Between the junction of the bore 17 in the cavity 7 and the holder 6 of the insertion needle 2, an elastic plug 18 is arranged, which is penetrated by the insertion needle 2. After insertion into the tissue, the insertion needle 2 is pulled out at its holder 6, after which the opening in the elastic plug 18 closes and this closes the cavity 7 automatically. The removal needle 1 is then ready to work immediately.

In the in Fig. 2 illustrated embodiment are respectively the variant of FIG, 1 corresponding parts provided with the same reference numerals. The second plastic cannula 12 is here connected in one piece with the first cannula 3, wherein the lumen of the second cannula can be arranged in the wall of the first. The terminals 10 and 11 can be shown in FIG. 2 and 3 may be molded directly into the handle part 8 and stand with the first cannula 3 or with the second 12 in conjunction. The terminals 10 and 11 can be shown in FIG. 1 or FIG. 3 have a common coupling part 21, in which the two terminals 10 and 11 due to their different dimensions or external shape, can be introduced confusion. Of course, it is also possible to dispense with a coupling part at all and to use a connector 9, which in one piece with corresponding devices or Evaluation devices leading lines is connected.

FIGS. 4a and 4b respectively show sections in the same area of ​​the needle tip once (FIG. 4a) with insertion needle and once (FIG. 4b) after removal of the insertion needle, whereby the lumen of the second cannula, which was previously slit or crescent-shaped, is unfolded.

The partition wall 20 between the first 3 and second cannula 12 has openings 22 in this area. The wall openings 5 ​​are not distributed over the entire circumference in the embodiments according to FIGS. 2 and 3, but are only in the area not claimed by the second cannula.

According to a detail of an embodiment variant of the withdrawal needle 1 shown in FIG. 5, only one opening 5 (or a smaller number of openings 5) can be provided in the outer cannula 3, which has a membrane 19 which is selective for certain sample constituents.