Antithrombotic Intravascular Catheter Reinforced With Nonkinking Means

Abstract

This invention relates to tubular catheters which are inserted through veins to enter the peritoneal cavity for medical purposes. Such tubing catheters have other medical applications such as for drainage or for introduction of medical materials, but since the tubing is of such a small diameter, it has been subject to difficulties in handling. The current invention circumvents problems caused by kinking during use by the application of a wire spring coiled around the tubing in interference fit and then coated with a silicone material to provide the surface finish required for insertion. The distal end of the catheter may be coated with an antithrombotic coating.

Description

DESCRIPTION OF THE INVENTION

This invention relates to surgical catheters.

An object of this invention is to provide a catheter for body implant, of small diameter, which will stand the stress of insertion through the veins or organs of a body.

Another object of the invention is to provide the tube-type catheter which can resist the stresses of insertion with kinking.

A further object of the invention is to provide tubing catheter which will not fail at the point where the tubing is applied to connecting devices.

Still another object of the invention is to provide tubing which will be self-guided into a vein and prevent kinking failure at its point of entrance.

Still another object of the invention is to provide a catheter which will curve over the muscles encountered during its course through the body without kinking.

A further object of the invention is to provide reinforced tubing that will be capable of penetrating muscles before entering body cavities without kinking or other mechanical failure.

Other objects and advantages of the instant invention will be shown by studying the figures and the description of invention, which follows:

FIG. 1 is a segment of an embodiment of the invention partially in cross section;

FIG. 2 is a side elevation of the embodiment of FIG. 1 before final coating;

FIG. 3 is a section on line 3--3 of FIG. 2; and

FIG. 4 shows the embodiment of the invention of FIG. 1 and FIG. 2 in process of final coating.

In FIG. 1 there is shown a preferred embodiment of the invention.

The tubing 10 is encircled by a continuous wire coil spring 11 which encircles the tubing in very close contact, preferably an interference fit, between the inside diameter of the the coil spring 11 and the outside diameter of the tubing 10. The tubing 10 for this class of article is of very small internal and external diameter, in the range of one-sixteenth inch. In order to provide the interference fit, the tubing is made with an entrance probe, as seen in FIG. 2. The entrance probe 12 may be conveniently formed on the tubing by thermoplastic means or may be a separate piece assembled to the tubing 10.

In order to make a coil spring of diameter that will be in interference fit with the tubing 10, the spring may be conveniently wound on a mandrel of larger diameter to form the coil and then elongated to provide the spacing of the coils and further to reduce the internal diameter of the coil spring 11.

A convenient length of tubing 10 with entrance probe 12 at one end is gripped by the entrance probe 12 and pulled through the coil 11 with sufficient force to overcome the interference fit between coil 11 and the outside diameter of tubing 10.

The tubing 10 is then suspended in air hanging from a fixture which engages entrance probe 12. A container 13 having a spout 14, the spout having an entrance hole 15, is passed over the tubing to the uppermost end so that entrance hole 15 is in a downward direction and the entrance hole 15 is so designed that it is a close fit to the outside diameter of the coil spring 11. The container 13 is then filled with a silicone material 16 which may conveniently be a silicone rubber of air-curing formulation. Silicone rubber is formulated to a viscosity which will cause it to cling to the exterior of the tubing 10 and fill the recesses between the coils of the spring 11 and form a coating 17 over said spring 11 and tubing 10 of the desired thickness. As the container 13 is allowed to move slowly downward over the tubing 10 and coil spring 11 assembly, the coated assembly of tubing 10 and coil spring 11 is then allowed to hang in air until the silicone material hardens to its final consistency.

One novel production method in assuring that the small diameter tubing may be pulled through in interference fit through the smaller internal diameter coil spring 11 is accomplished by fusing a cord or wire to the end of the tubing 10, so that the outside diameter does not have to be increased by adding a gripping means for pulling through the coil spring 11.

The distal end of the tubing, which is formed by the entrance probe 12 is coated with an antithrombotic coating, which may be of the nature of Hepacone, to prevent the formation of blood clots as the tubing is pulled through the body.

Thus it can be seen that a reinforced, small diameter tubing, which will not be subject to kinking and will not be reactive to the body fluids and is further provided with an entrance probe to permit passage through the body and a coating to prevent formation of thrombosis is provided by the instant invention, in accordance with the following claims.

Claims

I claim:

1. A surgical catheter comprising a flexible tubing made entirely of silicone rubber; an entrance probe integral with the flexible tubing and also made of silicone rubber, said entrance probe having a stepped-down outer diameter less than the outer diameter of the tubing and extending as a cylinder for a substantial distance; an antithrombotic coating of silicone rubber infused with heparin on said entrance probe; a flexible coil spring encircling and in interference fit with said tubing; and a surface coating of silicone rubber, once liquid and later cured to a solid, said coating fully covering the exposed surface of the spring and tubing and substantially filling in the interstices between convolutions of the spring.