Catheter

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a catheter comprising an elongated tube comprising a proximal tube and a distal tube, the distal tube forming the tip of the catheter.

【0002】

[Conventional technology]

A catheter is, among other things, a tube for establishing a fluid path that allows a portion of its length to be inserted into the body to inject a drug into the body or to remove a fluid from the body. When used for such purposes, the tube must meet special requirements. For example, the tube must be rigid enough to be inserted into the body. On the other hand, the tip of the catheter must be reasonably flexible so as not to damage blood vessels or other parts of the body.

【0003】

European Patent No. 0437291 is disclosed for a method of manufacturing a conventional flexible catheter tip. According to this European patent, the tip of a material that is more flexible than the catheter material is molded into the tube inside the catheter tube. The tip of the catheter tapers toward its distal end. In this way, a catheter with a flexible catheter tip can be obtained, avoiding the risk of internal damage.

【0004】

European Patent No. 0452123 discloses a catheter made of radiation-impermeable polyurethane halogenated. The catheter may be made of a number of different materials.

【0005】

European Patent Application Publication No. 0523928 discloses a venous indwelling catheter with a conical tip. The indwelling catheter is made of polyurethane and is designed to be placed inside the patient with the help of an inserted steel cannula. This polyurethane material has biocompatibility, is commercially available as an optically transparent radiation opaque material, has a smooth surface, and exhibits high bending resistance.

【0006】

Catheter with a flexible tip is also used to puncture the central vein. It has a flexible tip to reduce perforation of veins and damage to the endometrium. In addition, catheters with flexible tips are also used for epidural anesthesia to reduce damage to blood vessels and dura and the development of paresthesia. In cardiology, catheters with differently shaped tips are used to accommodate insertions into various shaped veins and arteries.

【0007】

[Problems to be Solved by the Invention]

An object of the present invention is to make it possible to manufacture a catheter that can be inserted into a patient's body by a simpler method at a low cost.

【0008】

[Means for solving problems]

According to the present invention, the above object is the outer diameter of the distal part of a tube in a catheter comprising an elongated tube comprising a proximal part of the tube and a distal part of the tube and made of the same material over its entire length. Can be achieved by reducing the size relative to the proximal part of the tube. The reduction or reduction of the outer diameter of the distal portion of the tube is obtained by stretching or stretching the catheter material, which is then plastically deformed. In that process, the length of the distal part of the tube increases and the lateral contraction causes the outer diameter to contract. The tube is made entirely of the same tube material and is deformed only by stretching. Therefore, it is not necessary to connect the two materials together to form a tube and thus a catheter.

【0009】

Stretching the distal part of the tube increases the flexibility and deformability of this part. Not only is it easier to push the distal part of the tube through the cannula, but it is also easier to advance the distal part of the tube with a guide wire.

【0010】

The present invention consists of a highly flexible, flexible distal tube and a fully insertable, stable proximal tube, and is constructed using a single substrate throughout the catheter. It makes it possible to provide a catheter that can be used.

【0011】

After stretching the catheter, it can also be cut to the desired length or shaped into a circle by post-treatment. In addition, it is possible to make a hole in the distal part of the tube.

【0012】

The present invention is used for local anesthesia catheters, particularly lumbar anesthesia catheters introduced into the spinal cord, epidural anesthesia catheters arranged in the epidural space on the side of the spinal cord, and plexus insertion catheters. Suitable. These catheters are used in combination with complementary local anesthesia cannulas, particularly lumbar anesthesia cannulas, epidural anesthesia cannulas or plexus cannulas.

【0013】

The distal tube is preferably substantially cylindrical and is at least 5 times, preferably at least 10 times, the outer diameter of the proximal tube. This means that the diameter of the entire distal tube, not just the tip of the catheter, has been reduced.

【0014】

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described in more detail below with reference to the accompanying drawings.

【0015】

The catheter 10 shown in FIG. 1 is an epidural catheter used for local anesthesia in which a local anesthetic is injected into, for example, the epidural space. The catheter 10 consists of an elongated tube 11 made of the same material over its entire length. The tube 11 consists of a proximal tube 12 and a distal tube 13. The total length of the catheter is 1000 mm. The proximal part 12 of the tube has an outer diameter of 0.85 mm and an inner diameter of 0.45 mm. Of course, this specification is just an example, and other dimensions are possible.

【0016】

The distal part 13 of the tube has a length of at least 10 mm. The outer diameter of the distal tube 13 has been reduced to about 80% of the outer diameter of the proximal tube. This reduction is brought about by stretching, and a transition region 14 is generated in the process of this processing. The extension is made by pulling in the longitudinal direction, where the proximal part 12 of the tube is clamped while the distal part 13 of the tube is pulled to extend its length. If desired, a mandrel can be used to assist in stretching. When the distal tube 13 is pulled assuming a longer one, the wall thickness of the distal tube 13 is reduced by lateral contraction. The catheter tip 15 is arranged at the distal end of the distal portion 13 of the tube, and in the present embodiment, it is formed on a circular tip cap 16 made of the material of the catheter. Alternatively, a central hole can be formed at the tip of the catheter. In the catheter 10 of FIG. 1, a side hole 17 is formed in the distal portion of the tube near the tip of the catheter so that liquid can flow out from the catheter through the side hole.

【0017】

FIG. 2 illustrates the case where the catheter 10 is used as an extradural catheter. Catheter 10 is used in conjunction with the Tuohie Cannula. The Tuohie cannula consists of a steel cannula 21 with a cannula hub 22 at its proximal end. A bent tip 23 is formed at the distal end of the cannula 21. As shown in FIG. 2, the cannula 20 penetrates the cortical layer 24 and advances between the vertebrae 25 of the spinal column and through the ligamentum flavum 26 into the epidural space 27. The catheter 10 is then inserted through the cannula 20. As the catheter 10 advances through the flexion tip 23 of the cannula 20, the catheter 10 bends according to the angle of the flexion tip 23 of the cannula and advances through the epidural space 27. The cannula 20 is then pulled up with the catheter 10 in place, and the catheter is ready to inject a local anesthetic into the epidural space 27. In this embodiment, the tapered tube distal portion 13 is approximately 5 cm long. This length corresponds to the length from the bending tip 23 of the cannula to the epidural space. The proximal part of the tube 12 is marked with a marking 28 to determine the insertion depth of the catheter.

【0018】

Figure 3 shows the catheter 10a used as a central venous catheter. This catheter is inserted to the immediate vicinity of the heart via the central vein, at which time the catheter tip 15 is first recommended to the right vestibule and pulled back to the hollow vein under ECG position control. The drug is then injected into the hollow vein through a catheter. The catheter comprises a guide wire, the tip of which is exposed to the outside from the catheter tip 15. Transmission of the captured electrocardiogram signal is performed via the guide wire.

【0019】

The total length of the catheter 10a is about 15 cm in the case of a central venous catheter.

【0020】

The catheter 10a consists of a distal tube 13 that is tapered relative to the proximal tube 12 relative to the proximal tube 12. Both tube parts 12 and 13 are all made of the same material. The distal part 13 of the tube has a length of at least 10 cm.

【0021】

As shown in FIG. 4, the catheter 10a is connected to a Y-shaped member 30 having two branch tubes 31 and 32. The branch tube 31 is connected to the catheter hub 33, and the branch tube 32 is connected to the catheter hub 34. Tube clamps 35 are provided on both branch pipes 31 and 32. The guide wire 36 passes through the branch tube 31 and the catheter 10a, and its distal end protrudes outward from the distal portion 15 of the catheter 10a, but the tip 37 of the guide wire 36 protruding outward is easily deformed. It is designed to do. The distal end of the induction wire 36 protruding from the catheter hub 33 is connected via a contact clamp 38 to a cable 39 that is designed to connect to an electrocardiogram display device. In this way, it becomes possible to monitor whether the catheter tip is positioned in the right vestibule or in the hollow vein by electrocardiogram position control.

【0022】

The diameter of the guide wire 36 is such that it can be advanced within the distal portion 13 of the tube without significant friction. The wire exits through the central hole in the catheter tip 15. The edges of the holes are rounded.

【0023】

Although the catheter 10a in the embodiment of the present invention has one lumen, a structure having a plurality of lumens is also possible. Even in this case, by extending the distal portion 13 of the tube, the diameter of all lumens is reduced.

【0024】

The entire catheter is made of the same material. However, as an alternative, the catheter can be a two-layer or multi-layer structure consisting of an inner tube and an outer tube, which can be manufactured specifically by simultaneous extrusion of both tubes. Is.

【0025】

Particularly useful materials for topical dural catheters include a combination of PA-PUs in which the inner tube is made of polyamide and the outer tube is made of polyurethane. Particularly useful materials for central venous catheters include PU-PU combinations made of different polyurethanes, and indwelling venous cannulas preferably have PA-PA combinations made of different polyamides.

【0026】

[Effect of the invention]

It is clear that the present invention provides a catheter consisting of a highly flexible, flexible distal tube and a stable proximal tube with sufficient insertability. Moreover, it is clear that a kind of raw material is sufficient for the entire catheter.

[Simple explanation of drawings]

[Figure 1]

It is a longitudinal sectional view of the epidural catheter according to the present invention in which the tip of the catheter is occluded.

[Figure 2]

It is explanatory drawing which shows the use example of the catheter of FIG.

[Fig. 3]

It is a longitudinal sectional view of a central venous catheter.

[Fig. 4]

It is an overall view of the said central venous catheter.

[Explanation of symbols]

12 Tube proximal part 13 Distal part of tube 15 Catheter tip 16 Circular tip cap 17 Side hole 21 ... Cannula 22 Cannula hub