JPH012662A - Easy-to-split plastic cannula with excellent stability - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to improvements in easily splittable plastic cannulae used when inserting long catheters into body cavities such as blood vessels.

(Prior art) A general plastic cannula has the role of securing an introduction part for smoothly introducing a long catheter etc. into a body cavity. It will interfere with the subsequent procedure. Therefore, a type of plastic cannulae that can be separated and removed after insertion has been developed.

Such easily splittable plastic cannulas are disclosed in, for example, Japanese Utility Model Publication No. 1661/1983 and Japanese Patent Application Laid-Open No. 110/1983.
This method is known from Japanese Patent Application Laid-Open No. 59-91968, and the like. With the structures described in these known documents, once the role of guiding the catheter is completed,
It allows it to be torn or split lengthwise so that it can be pulled out of the body cavity and removed.

(Problem to be Solved by the Invention) In the above-mentioned conventional technology, once the object has finished its role, it can be pulled out and removed from the body cavity.
For this reason, there have been cases in which the device cracks along this line of weakness when inserted into tissue and before it has stabilized, or it may break along this line of weakness from the tip opening during storage and transportation. This phenomenon cannot be seen visually unless you check it by pressing the tip with your hand, and when actually used on a patient,
This can often be determined by the patient's pain. This was a big problem that needed to be solved from a humane standpoint, but if we pursued the original function of breakability, the above problems would become even worse, so we had to try to solve this problem instead. However, this phenomenon has remained unsolved until now because it is a trade-off phenomenon in that it becomes difficult to break.

(Means for Solving the Problems) As a result of extensive research, the present inventors have found that in order to solve the above-mentioned drawbacks, it is necessary to separate them at an angle of 45 to 180 degrees in the circumferential direction and parallel to the length direction. It has been found that, in a part of a cannula made of a plastic tube having two or more lines of weakness extending in the vicinity of the distal end opening, the lines of weakness of the tube may be twisted in the longitudinal direction.

Furthermore, in order to complete this as an industrial product, it was constructed from a plastic tube with a line of weakness and a plastic adapter that was joined together at the proximal end of this tube, so that the line of weakness on the outer surface of the adapter was connected to the tube. It has been found that it is sufficient to form a weakening groove that connects two of the lines of weakness and induces breakability in the lines of weakness.

In addition, when twisting the line of weakness of the tube in the longitudinal direction, the range is 0.3 to 3.011 mm from the tip opening.
As for the way of twisting, it is preferable that the pitch is 6 m1 rotation or less.

Furthermore, it is preferred that the adapter includes two integrally formed handles projecting laterally at positions equidistant from the two weakening grooves. Further, the weakened groove has a cross-sectional shape such as a V-shape, a U-shape, a semicircle, or a U-shape, and the groove extends from the end of the adapter connected to the tube to the proximal end. It is preferable that the adapter portion is deep, and that the proximal end and its vicinity constitute a relatively strong adapter portion. Furthermore, it is preferable if the adapter has a tube proximal opening that can fit tightly into the syringe barrel.

(Function) The reason why the line of weakness of a cannula made of a plastic tube is twisted in the longitudinal direction near the opening of the tube is to cause a crack to occur along the line of weakness from the tip opening. and/or to prevent it from progressing. The twisting range is 0.3 to 3.0 from the tip.
Me, preferably 1.0 to 2. However, this is because if the length is longer than this, it will exhibit a large resistance to tearing from the proximal end, resulting in poor divisibility. Also,
o.If it is shorter than 3 mrtt, it will not be possible to expect the effect of preventing cracks from occurring and/or propagating from the tip opening along the line of weakness, and it will be difficult to industrially manufacture homogeneous products. be.

The degree to which the line of weakness of the tube is twisted in the longitudinal direction is preferably 6 pinches/rotation or less;
This is because below this value, the effect of preventing cracks from progressing from the tip opening along the line of weakness cannot be expected.

Furthermore, if the pitch is less than 1 mm/rotation, it will be very difficult to divide the tip of the tube, so there is no need to make it less than this.

In the present invention, the lines of weakness must be separated by an angle of 45 to 180 degrees in the circumferential direction, but this means that if the line of weakness is less than 45 degrees, when the tube is divided, the tube of the divided portion will strongly impact the inserted catheter. This is because it is often extremely difficult to trap and remove them. The angle at which this easy dividing property is more effective is 100 to 180 degrees, but when dividing,
If you want to reduce the shock when dividing the cannula and reduce the damage to the patient's tissue by intentionally leaving the catheter in one of the divided parts,
Preferably, the angle is 50 degrees.

In the present invention, a single line of weakness applies a large impact to the inserted catheter, placing a large burden on the patient's tissues, and there is no point in combining the adapters of the present invention. Although it is possible to provide a wire, there are many difficulties in the industrial manufacturing process, and therefore two wires of weakness are most commonly used in practice.

In the present invention, within the line of weakness of the tube on its outer surface,
It is preferable to include an adapter that connects the two tubes and forms a weakening groove, which prevents cracks from forming and propagating along the line of weakness of the tube from the proximal end. For the same reason, two handles integrally formed so as to protrude laterally are provided at positions equidistant from the two lines of weakness of the adapter. is effective.

(Example) Example 1: As shown in FIG. 1, there are two lines of weakness that are separated by an angle of 180 degrees in the circumferential direction and extend parallel to the longitudinal direction, and 1. A hard polyethylene cannula with a pitch of 1.38 mm and an AU twist was manufactured with a length of 'mx. (FIG. 2) Comparative Example 1: A cannula was manufactured using the same material as in Example 1 and having the same shape but without twisting of the line of weakness in the vicinity of the tip opening. (Fig. 3) Examples 2 to 5: Using the same material as in Example 1, cannulae having the same shape but different pitches of twist from the tip opening were manufactured.

Examples 7 to 12: Using the same material as in Example 1, cannulae having the same shape but different twist lengths from the tip opening were manufactured.

Examples 13 and 14: Each has three or two lines of weakness separated by an angle of 120 degrees in the circumferential direction and extending parallel to the longitudinal direction, with a length of 1.5 u from the tip opening, and a pitch of 1.82. Homo: I made a polypropylene cannula with rotational twist.

For each of the above products, 100 pieces were evaluated for appearance, ease of division, and stability of the tip opening (first, 90 pieces were
Table 1 shows the results of measuring the crack occurrence condition by repeating the operation of rotating the sample 5 times and crushing it with your fingers 5 times.

As can be seen from Table 1, when the length of twist is less than 0.3 mm, the stability of the line of weakness becomes poor, and when it is more than 3.00 mm, the appearance and ease of dividing become poor. Also, the twist pitch is (
,00 h/rotation or more, the stability of the line of weakness decreases.

(Effects of the Invention) As shown above, the easily splittable plastic cannula of the present invention is difficult to split from the distal end, but on the contrary, it is easy to split from the proximal end, and the distal end is free from cracks from the proximal end. In response to advances in technology, it has become possible to smoothly divide plastic cannulae, dramatically improving safety, stability, and applicability, and supplying easy-to-divide plastic cannulae that can be used with peace of mind for patients.

[Brief explanation of the drawing]

FIG. 1 is a front view of an easily split plastic cannula. FIG. 2 is an enlarged front view of the distal end of the easily splittable plastic cannula according to Example 1 according to the present invention. Figure 3 shows the conventional method of easy-to-split plastic that does not twist.
FIG. 3 is an enlarged front view of the tip of the cannula.

Claims (6)

[Claims] (1) separated by an angle of 45 to 180 degrees in the circumferential direction,
A plastic cannula comprising a plastic tube having two or more lines of weakness extending parallel to the longitudinal direction, characterized in that the lines of weakness of the tube are twisted with respect to the longitudinal direction in the vicinity of the tip opening. Easily split plastic cannula. (2) Consists of a plastic tube with a line of weakness and a plastic adapter joined together at the proximal end of the tube, with the adapter having an inner diameter hole communicating with the inside of the tube, and a hole communicating with the inside of the tube on its outer surface. The easily split plastic cannula according to claim 1, further comprising a weakened line that connects two of the weakened lines of the tube and forms a weakened groove. (3) The length of the twisted portion of the line of weakness in the longitudinal direction of the tube is 0.0 mm from the tip opening. ^3～3. ＾0mm, preferably 1. ＾0～2. The easily splittable plastic according to claim 1, characterized in that it has a diameter of 0 mm.
Kanyura. (4) The easily splittable cannula according to claim 1, wherein the twisting portion of the tube in the longitudinal direction of the line of weakness has a pitch of 6 mm/rotation or less. (5) The adapter includes two handles that are integrally formed so as to protrude laterally from the two weakened grooves at positions equidistant from each other. The easily split plastic cannula described in item 2. (6) The weakened groove has a V-shaped, U-shaped, semicircular, or square cross-sectional shape, and the groove extends from the end of the adapter where it is joined to the tube to the proximal end. 3. The easily splittable plastic cannula according to claim 2, which has a deeper depth and further has a proximal end and its vicinity constituting a relatively strong adapter part.