DK143382B - BLOOD SAMPLING CANNON APPLIANCE - Google Patents

Description

| J | (12) SUBMISSION WRITING out 143382 B

(19) DENMARK

DIRECTORATE OF THE PATENT AND TRADEMARKET SYSTEM

(21) Application No. 5550/75 (51) IntCl. * A 61 B 5/14 (22) Filing date 27 · Jun. 1975 (24) Race day 27 · Jun. 1975 (41) Atm. available Dec 29 1975 (44) Presented Aug. 17-Aug. 1981 (86) International Application No. - (86) International Filing Day - (85) Continuation Day - (62) Master Application No. -

(30) Priority 28 Jun. 1972, 266996, US

(71) Applicant BECTON DICKINSON AND COMPANY, East Rutherford, US.

(72) Invented Waldemar Alexander Ayres, US.

(74) International Patent Bureau.

(54) Blood sampling cannula.

Various methods and apparatus are known for blood sampling in a patient. In a commonly used method, blood from a vein is flowed through a cannula and into an evacuated container. This evacuated container provides the pressure drop needed to facilitate blood flow to and collection in the container through the cannula. The basic method and associated apparatus for collecting blood in this manner is disclosed in the disclosure of U.S. Patent No. 2,689,564.

g In recent years various improvements have been proposed in this method O for blood sampling, for example insertion of a valve into the apparatus for auto-

ISLAND

jumatic opening and closing of the flow path so that several evacuated vessels may be flowingly connected to the apparatus when multiple blood samples are desired to be collected in a corresponding number of vessels from one and the same venous puncture. Needle devices with such automatic valves are known, for example, from the disclosures of U.S. Patents 3,469,572 and 3,494,352.

Often, the evacuated containers contain chemicals useful in the clinical laboratory studies to be performed after mixing with the patient's blood. However, these chemicals can be harmful to the patient and should therefore be prevented from flowing from the evacuated container into the patient's bloodstream. This problem has been satisfactorily resolved by means of a non-return valve shown and described in the parallel patent application No. 3549/73.

With apparatus of the kind mentioned above, it has often proved desirable to have some sort of indication or marking on the cannula apparatus to inform the user when the venous puncture has been completed. After the venous puncture has taken place and has been indicated or marked, the necessary measures for this purpose will no longer be necessary and thus can be avoided during the continued use of the apparatus when one or more blood tests are to be taken without risk of reflux. Therefore, a single apparatus with a non-return valve is needed when multiple blood samples are to be taken from a single venous puncture and collected in each container, avoiding the risk of backflow from the container to the patient, and where the apparatus further has blood flow indication means. showing that a venous puncture has been performed so that the evacuated collector can be brought into full flow with the cannula apparatus.

In this context, the invention relates to a blood sampling device for a patient, which in a known manner comprises a housing containing a chamber and has first a first needle for insertion into the patient's blood vessel and a second longitudinally displaceable needle between a rear and anterior position relative to the housing and in the latter position adapted to direct blood which has flowed into the chamber through the first cannula into a replaceable collecting vessel and in connection with the chamber there is a valve arrangement for interruption of blood flow through the second cannula when it is in its posterior position.

In an apparatus of this kind known from U.S. Pat. No. 3,659,587, the anterior cannula is permanently open to the chamber of the housing, while the second or posterior cannula can be brought into contact with the same chamber by forcing through a self-closing slot in a valve disc.

In contrast, the apparatus according to the invention is characterized in that the first cannula with its rear end extends into the chamber and carries a valve bush which is displaceable on the cannula between a first position in which blood from the patient through one or more this position 3 open passageways may flow into the chamber to serve as a visual signal for marking blood vessel punctures, and another position in which the passage (s) is closed to prevent back flow of blood from the chamber to the blood vessel and has one of its position relative to the cannula independently acting non-return valve which allows flow of blood to the chamber when the pressure in it is lower than that of the cannula, and that the other cannula is connected to the chamber through a passage open in the front of this cannula position and locked in its rear position.

This particular arrangement fulfills two purposes, namely to first allow the user of the apparatus to see when the blood vessel puncture has been completed, and then under the normal operating conditions, to enable continued blood flow to the chamber and further through the second cannula to the collecting vessel, and partly to exclude flow. in the opposite direction through the first cannula, that is, from the chamber to the patient, and further, the blood flow through the second cannula is excluded in its posterior position, which it is automatically brought into by exchanging an entire or partially filled collecting container with an empty container.

When the apparatus is of the prior art, which has a holder for receiving a collecting container which is pressurized before use and is closed by means of a rubber plug plug facing the rear end of the other cannula, the displacement of the second cannula may conveniently be secured by that this second cannula is arranged, partly by the insertion of the canister into the holder, first to be displaced to its forward position, thereby being brought into open communication with the chamber and then to pierce the plug, and partly by removing the canister from the stopper, until the cannula is again itself in its rear position and is out of flow communication with the chamber. This eliminates special manipulations or special attention on the part of the user as far as the second cannula's movement between the two end positions is concerned.

For similar purposes, the valve sleeve may be movable from its first to its second position by actuation from the second cannula during its displacement from the rear to the front position. This can in practice be conveniently ensured by the valve sleeve being displaceable from its first to its second position by means of a groove fixed to the front end of the second cannula which lies around the valve sleeve and with its edge portion abutting a collar or flange at the open end of the bushing. Hereby, by simple means, a reliable function of the apparatus is achieved,

The invention is explained in more detail below with reference to the drawing, in which: FIG. 1 shows a side view of an embodiment of a cannula apparatus according to the invention in connection with a holder and with an evacuated container in position for connection with the apparatus; FIG. 2 shows a corresponding section in larger scale and with some parts omitted and after an indicated venous puncture and before the valve closure first, FIG. 3 is a sectional view of an even larger scale of the cannula apparatus itself in the same situation; FIG. 4 is a view of FIG. 2 is a sectional view corresponding to displacement of the valve member to the closed position after indicating a venous puncture and prior to establishing full flow connection with an evacuated collecting container; FIG. 5 shows a corresponding section in larger scale of the cannula apparatus itself in FIG. 4, FIG. 6 is a view of FIG. 2 and 4 correspond to sections of the apparatus with an evacuated collector in full flow communication with the cannula apparatus and with the valve member in the open position to allow blood to flow from the vein to the collector; FIG. 7 is an enlarged sectional view of the cannula assembly itself of FIG.

6, FIG. 8 is a view of FIG. 2, 4 and 6, corresponding to a sectional view of the apparatus after removing the collecting container and with the valve member in the closing position to prevent flow between the ends of the cannula apparatus; FIG. 9 is an enlarged sectional view of the cannula apparatus itself in the same situation as in FIG. 8, and FIG. 10 is a perspective view of the cannula apparatus itself with the individual parts pulled apart.

In the embodiment of FIG. 10 shows a housing 21 consisting of two parts, namely a front part 22 and a rear part 23. The front part 22 carries a cannula 24 and another cannula 25 is placed in the rear part 23. When the front part 22 are assembled with the rear portion 23 together forming a chamber 26 as shown in FIG. 1-9. In this chamber is an elastomeric sleeve 27, a rigid groove 28, a holding plate 29 and an elastomeric sealing disc 30.

The front portion 22 of the housing has a slightly tapered exterior surface 31 which can be frictionally connected to an inner cylindrical surface 32 of the rear housing portion 23. This friction joint is sufficiently strong to prevent separation of the portions of the housing 21 during use of the apparatus. If desired, connection of the two parts of the housing 21 can be further ensured, for example by introducing an adhesive between the surfaces 31 and 32.

A passage 33 in the front portion 22 connects the front end of this portion to the chamber 26. The cannula 24 is disposed within this passage 33 and extends with its rear portion 34 into the chamber 26. Its front end terminates at a tip 35 which is slightly projected from the housing portion 22 and is sharpened for use in venipuncture.

The rear portion 23 of the housing has a cylindrical body portion 36 which is assembled with the front portion 22 and constitutes the major portion of the restriction of the chamber 26. At the rear end, the housing portion 23 has a stud with an external thread 37 for screwing into a holder. 38. This holder 38 serves as a guide for receiving an evacuated collection container 39, consisting of a tube 40, which is at least partially pumped out and closed at the top by a self-closing, permeable plug 41.

The rear housing portion 23 contains an axial passageway 42 which connects from the rear end of the housing 21 to the chamber 26. The cannula 25 is slidably disposed in this passageway 42.

The rear end of the cannula 25 extends a little outward from the housing 21 and has a sharpened tip 43 for piercing the plug 41 in the evacuated container 39. The other end 44 of the cannula extends into the chamber 26.

In this end portion, the cannula 25 has a side opening 45 which is displaced into and out of the chamber 26 as the cannula 25 is displaced during use of the cannula apparatus. The sealing disc 30 abuts against the back wall of the chamber 26 and has a center opening of a diameter smaller than the outer diameter of the cannula 25, so that the elastomeric sealing disc 30 maintains close contact with the cannula 25 during the mutual displacement of these two parts. Hereby the chamber 26 is kept closed so that leakage is prevented at the rear end of the housing 21. To improve the sealing effect of the disc 30, the rigid plate 29 is placed at the rear end of the housing 21 and is in frictional engagement with the side walls of the housing so that it is elastomeric. washer 30 is retained between the underside of plate 29 and the back wall of the housing. This may, as shown, have an annular collar or elevation 46 for abutment of the underside of the disc 30, thereby intensifying its sealing effect so that leakage from the chamber 26 through the passage 42 in the housing 21 is excluded.

The shelf 28 is disposed on the inner blunt end 44 of the cannula 25 and is securely attached thereto, e.g. by means of an adhesive 47. The tulle 28 can consist of a plastic material and closes the respective end 44 of the cannula 25. The only access from the chamber 26 to the bore in the cannula 25 is consequently the side opening 45 of the cannula 28. The upper end of the tulle 28 is open. , and near the closed end of the cannula 25, the tulle has a number of side ports 48, for example four, as shown in the drawing. These side gates are evenly distributed along the circumference of the tulle. The outer diameter of the tulle is smaller than the inner diameter of the housing 21, so that the tulle can be freely displaced axially with the needle or cannula 25. The tulle 28 is cylindrical and can accommodate most of the sleeve 27 with a suitable clearance so that the tulle 28 can be displaced. back and forth relative to the sleeve 27. The upper open end of the tulle 28 abutment abuts a flange 50 about the open end of the sleeve 27. This, with its open end, is projected into the rear end.134 of the needle 24, as appropriate, e.g. by means of an adhesive 51, is fixed in the passage 33. of the housing 21 At the open end, the sleeve 27 is expanded so that it engages in friction engagement with the rear portion 34 of the cannula 24 and encloses it tightly. The bush 27 is slidable between an unstressed starting position; 2 and 3, and a tense position as shown for example in FIG. 4-9. The sleeve 27 has a central passage 52 for receiving the rear portion 34 of the cannula 24. In the unstressed starting position, FIG. 2 and 3, the cannula 24 is enclosed only by the front open portion of the sleeve 27 which, behind the blunt end 53 of the cannula 24, has one or more cross holes 54 which connect the inside to the outside of the sleeve 27. Near its rear end, the sleeve 27 further has a slot 55 which is normally closed due to the resilient properties of the sleeve 27. Any well-known, elastomeric, self-sealing material such as natural or synthetic rubber can be used for the sleeve 27.

The parts of the housing 21 as well as the tulle 28 may consist of transparent plastic material, so that it is easy to visually detect if there is blood in the housing. The sleeve 27 may also consist of a transparent elastomeric material, but this is usually not the case because the blood will flow into the spaces around the sleeve and thus become visible through the transparent parts of the housing during the indication phase, as will be explained in more detail below. . All the parts included in the apparatus, with the exception of the needles and sleeve, may consist of ordinary, cheap plastic material or other material which is readily available.

As mentioned above, the cannula 25 is slidable in and out of the housing, and the migration in this displacement may be limited by appropriate stops. The force for moving the cannula 25 is transmitted through the friction between this cannula and the plug 41 as the evacuated tube 39 is displaced in the holder 38 during blood collection. Despite its displaceability, the cannula 25 is constantly hermetically sealed relative to the port or passage 42, namely by the elastomeric sealing disc 30 pierced by the cannula 25.

FIG. 1 shows the cannula apparatus in a ready-to-use position and after being screwed together with a holder 38 with an evacuated container 39 ready for engagement with the cannula apparatus. The stuck needle or cannula 24 is carried by the cylindrical portion 22 of the housing 21 and is secured tightly, e.g. by means of the adhesive 51. The rear end portion 34 of the cannula 24 enters the passage 52 of the elastomeric sleeve 27, the wall of which has a close abutment to the outside of the cannula 24. In the starting position of the cannula apparatus, fig. 1-3, the transverse holes 54 in the sleeve 27 are located behind the rear end of the cannula 24. Accordingly, open passage from the cannula tip 35 through the apparatus to the side opening 45 of the slidable cannula 25.

When the sleeve 27 is pushed forward to enclose the entire rear portion 34 of the cannula 24 so that the flange 50 at the front end of the sleeve abuts against the end wall of the housing, the cannula will have closed the transverse openings 54 in the sleeve 27 to block the cannula 24th

143382 7

The displaceable cannula 25 carries the valve tuck 28, its front end 44 being inserted into a recess at the rear end of the tulle 28 and sealed thereto by an adhesive 47 or other suitable means. The inner diameter of the cylindrical groove 28 is substantially larger than the outer diameter of the sleeve 27, so that blood or air can flow freely out of the valve sleeve 27 and into the spaces between this sleeve and the groove 28 and out through one or more of the groove side ports 48.

As best seen in FIG. 10, the slightly tapered outer surface 31 of the housing portion 22 seals tightly with the inner surface 32 of the cylindrical rear portion 23. This carries the displaceable cannula 25 in the passage 42 at the rear end of portion 23. The rear housing portion 23 further carries the elastomeric seal disc 30 and the associated holding plate 29. This may be molded in a suitable plastic material or may consist of any other material having suitable properties. Its outer diameter is sufficiently large to ensure clamp fit in a narrowed portion of housing portion 23. Upon providing the seal, the housing portion 23 is placed in a vertical position and the elastomeric seal disc 30 is dropped into the housing portion so that it will lie across the end of the passage. 42. Then, the retaining plate 29, which is stopped by the narrowed portion 56 at the rear end of the housing portion 23. follows by means of a mandrel or other tool, the plate 29 can be pressed to the bottom so that the annular collar or elevation 46 on the inside of the housing portion The end wall of 23 penetrates elastomeric disc 30 to ensure a coherent seal.

Then, the tulle 28 is assembled with the end of the cannula 25, conveniently using a suitable adhesive, and the sharpened end 43 of the cannula 25 is inserted through the center hole of the retaining plate 29 and pierces the elastomeric disc 30 until it engages it in FIG. 1-3. The housing portion 22 with the cannula 24 is then pushed into the housing portion 23 until the slightly tapered portions are sealed against each other. At this junction, the end portion 34 of the cannula 24 is simultaneously slid into the open end of the sleeve 27, and the apparatus is now ready for use with the various parts located as shown in FIG. Third

The studs of the housing portion 23 with the thread 37 are screwed into the corresponding thread in the holder 38 and an evacuated container 39 is placed in the rear of this holder 38. This situation is shown in FIG. 1. The plug 41 should not be connected with any portion to the posterior end of the cannula 25 until the cannula 24 is inserted into the vein of the patient. This is a condition for the blood flow indicator of the cannula to function as intended.

When the needle 35 of the needle 24 is inserted into the patient's vein as shown in FIG. 2 and 3, through the apparatus there will be open flow passage for the blood through the cannula 24 and out through the transverse holes 54 in the bush 27 to the space between its outside and the inside of the tulle 28 and out through its gates 8. The blood will then begin to fill it. mainly cylindrical space around the tulle 28 in chamber 26. If the blood is allowed to continue flowing, it will pass through the side opening 45 into the displaceable cannula 25 and out through its sharpened rear end 43. This free blood flow is caused by the venous pressure in the patient. When the blood substantially fills the chamber 26, it will be easily seen by the operator who will draw attention to this blood flow indication and then shoot the evacuated container 39 fully into the holder 38, thereby passing the needle 25 through the plug 41. If the container or tube 39 is wound in the holder 38, the needle or cannula 25 is immediately displaced forwardly so that the sleeve 27 is forced all the way to the rear end 34 of the cannula 24 until its flange 50 abuts against the end wall 57 of the housing 21, forming an effective stop. This . movement transfer depends on the connection between the cannula 25, the tulle 28 and the bushing 27. The only resistance to the displacement of the needle or cannula 25 is the friction between the sealing disc 30 and the outside of the cannula 25.

This friction is substantially less than the friction that the cannula 25 must overcome by piercing the body 41. Consequently, the sleeve 27 will move to its active position as a valve member before the cannula 25 enters the evacuated tube 40. The sleeve 27 remains in its active position as valve member. FIG. 4 and 5 show the apparatus after the sleeve 27 is pushed forward to its forward position to act as a valve and immediately before the plug 41 is pierced by the needle 25.

In FIG. 6 and 7, the forward movement of the evacuated container is accomplished and connection is made between the cannula 25 and the space of the tube 39. As shown, this causes the slot 55 to open due to the pressure drop due to the vacuum prevailing in the container 39. and blood will now flow to the tube 40 along the path shown by arrows in FIG. 7. When, after filling the tube 40 with blood, it is desired to fill one or more additional tubes, the operator pulls the container 39 out of the holder. Below, the friction between the stopper 41 and the cannula 25 will be substantially greater than the friction between the cannula 25 and the sealing disc 30, so that the cannula 25 is displaced backward until the rear end of the tulle 28 abuts the retaining disc 29, which in this situation provides an effective stop. Only then cannula 25 is pulled out of plug 41. Cannula 25's side opening 45 is now below or behind sealing disc 30 so that no more blood can flow out of cannula 25 until the next container 39 is fully inserted into the holder. Hereby, the cannula 25 and tulle 28 will again be displaced forwardly, thereby exposing the aperture 45 to the chamber 26 and allowing blood to flow into the vessel when the cannula 25 is fully inserted into the evacuated tube 40. The device's locking position between the completion of the first blood sampling and the insertion of the next collector 39 is shown in FIG.

Claims (2)

9 and 8. It should be noted that the cannula tip 35 remains in the patient's vein, thereby enabling multiple sample drawings in a series of collecting vessels with only a single venous puncture. After the desired number of samples is obtained, the cannula can be discarded as waste. From the foregoing statement, it can be seen that the cannula apparatus 20 performs several functions. It acts as a non-return valve that normally closes and eliminates the risk of backflow during blood sampling, and it also acts as a blood flow indicator that allows the operator to detect when a venous puncture has been performed and further allows the cannula to take any number of blood tests with only a single venous puncture. Thus, the apparatus according to the invention effectively fulfills the aforementioned objects. An apparatus for blood sampling in a patient, comprising a housing (21) containing a chamber (26) and having first a first needle (24) for insertion into the patient's blood vessel and a second needle (25) slidable in its longitudinal direction between a rear and anterior position relative to the housing and in the latter position is adapted to direct blood flowing through the first cannula into the chamber into a replaceable collecting container (40), and with the chamber there is a valve arrangement for interrupting the flow of blood through the second cannula when it is in its rear position, characterized in that the first cannula (24) with its rear end extends into the chamber (26) and in this carries a valve bushing (27) which is displaceable on the cannula between a first position in which blood from the patient through one or more open passages (54) can flow into the chamber (26) to serve as a visual signal for marking blood vessel puncture the passage of the trip, and another position in which the passage or passages are closed to prevent backflow of blood from the chamber to the blood vessel and the valve sleeve (27) has one of its position relative to the cannula (24) independently acting check valve (55) allowing blood flow to the chamber (26) when the pressure therein is lower than the cannula, and the second cannula (25) is connected to the chamber (26) through a passage (45) open in the front of this cannula position and locked in its rear position. The apparatus of claim 1 and having a holder for receiving a collecting container (40) which, prior to use, is pressurized and is closed by means of a protruding plug (41) facing the rear of the second cannula (25),