United States Patent 3736939

A flexible retention catheter of the balloon inflation type is provided with an auxiliary drainage opening in the wall of the catheter, situated below the inflation balloon, and with an imperforate tip composed of a material which is soluble in body fluids. During insertion, drainage is initiated only through the auxiliary opening. Upon dissolution of the tip, the whole diameter of the lumen of the catheter becomes available for drainage.

Application Number:
Publication Date:
Filing Date:
Primary Class:
Other Classes:
604/96.01, 604/275, 604/915
International Classes:
A61F2/958; A61M25/00; A61M25/16; (IPC1-7): A61M25/00
Field of Search:
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US Patent References:
3428046CATHETER1969-02-18Remer et al.
2936760Positive pressure catheter1960-05-17Gants
2930377Surgical tube1960-03-29Cowley

Other References:

Brit. Med. Journ. 25 Feb. 1967 pg. 485.
Primary Examiner:
Truluck, Dalton L.
Parent Case Data:

This is a continuation of application Ser. No. 1,471, filed Jan. 8, 1970, which is a continuation-in-part of U. S. Ser. No. 692,853, filed Dec. 22, 1970, both now abandoned.
Having thus described my invention, I claim

1. A flexible retention catheter of the balloon inflation type which comprises

This invention relates to surgical retention catheters, and more particularly to catheters provided with an imperforate, transient, water-soluble tip.

Conventional catheters of the balloon-inflated retention type are generally provided at one end with a rounded tip or head containing one or more elongated openings to allow for the drainage of body fluids through the catheter. These drainage openings in the tip of the catheter are limited in size, since the larger they are, the more they tend to decrease the rigidity and resistance to distortion of the tip. Ideally, the insertion tip of a catheter should be as resistant to distortion as the body portion thereof, to resist doubling over upon insertion, with consequent discomfort and pain to the patient.

As a result of this physical limitation on the size of the openings in the catheter tip, the drainage of viscous fluids is impeded. Furthermore, sediment or fragments of tissue may accumulate in and around the eyelets or openings, with a slowing down or even complete stoppage of the drainage function.

Ideally, once the catheter is in place, it would be desirable to utilize the maximum drainage capacity of the catheter by having the end of the catheter open and untipped. Open-end catheters have been proposed wherein the tipless open end of the catheter tube is provided with inserted reinforcing strips of latex-impregnated fabric, as in U. S. Pat. No. 2,677,375. However, such catheters do not have a smoothly rounded tip, so that an unprotected and uncovered edge of the tube end comes in contact with the passage through which the catheter is being threaded, with the danger of injury to the patent.

It has also been proposed to provide irrigation devices with tips which become soluble in aqueous fluids. However, all of such devices known to me have soluble tips which are perforate, in that they contain one or more drainage openings in the tip itself. Such devices are not well-suited to function as retention catheters of the balloon inflation type, since as soon as the perforate tip enters the bladder, drainage will begin. The nurse will then inflate the retention balloon, which may or may not be situated in the desired position inside the bladder and resting against the bladder wall. If the balloon is still in the upper portion of the urethral canal, its inflation is accompanied by extreme discomfort to the patient.

It is an object of this invention to provide a retention catheter of the balloon inflation type which can be inserted with maximum ease and lack of discomfort and which, once in place, offers maximum drainage capacity, and which minimizes the danger of premature inflation.

It is a further object of this invention to provide a retention catheter with a rounded, imperforate atraumatic tip which is capable of dissolving in body fluids.

The invention will be better understood with reference to the following description and drawing, in which:

FIG. 1 is a cross-sectional view of the catheter of this invention.

Referring to FIG. 1, there is shown an inflation catheter with a flexible body portion comprising sidewalls 12--12, of conventional construction, surrounding the drainage lumen 11. The insertion end of the catheter is provided with a tightly fitting rounded imperforate tip 10 formed from a substance which is firm and resilient when dry, but is capable of softening and dissolving in body fluids such as urine.

The catheter of this invention is of the inflation balloon type, wherein the drainage lumen 11 is provided with an inflation wall channel 22, said channel having the conventional angularly disposed inflation connection, not shown, by means of which fluid is transmitted through the channel and the communicating opening 20 to inflate the balloon 18, situated near the distal end of the body of the catheter and sealed thereto, said balloon and inflation lumen being well-known and conventional.

The catheter is also provided with an auxiliary drainage opening 24 in the wall 12, opening directly into the main drainage lumen 11. Such an opening assists in the drainage of small subnatant pockets of body fluids which may accumulate when the inflation of the balloon walls 18 causes the open tip of an indwelling catheter to project an appreciable distance beyond, for instance, the wall of the human bladder. More importantly, as the catheter is being inserted, the actual soluble tip of the catheter is closed, and drainage can begin only through this auxiliary opening 24. Thus, during the insertion process, the initiation of drainage is a sure sign to the nurse that the balloon portion of the catheter is inside the bladder, and that inflation can be safely carried out without discomfort to the patient.

The imperforate water-soluble catheter tip 10 should fit snugly and firmly over the open end of the catheter tube. It is, however, generally of thinner wall construction than the walls 12 of the catheter, a wall thickness of 2-5 mils facilitating satisfactorily rapid disintegration when the tip is immersed in, for example, urine. It may be fashioned from any suitable substance which has the property of forming a solid film capable of softening and dissolving in aqueous fluids, such as gelatin, methyl cellulose, polyvinyl alchol, polyethylene oxide, polyvinyl pyrrolidone, and the like. These may be used alone, or in combination with water-soluble non-toxic plasticizers such as various glycols, to obtain the desired combination of flexibility and disintegration time. The substance chosen preferably will disintegrate and dissolve substantially completely when immersed in an aqueous fluid of pH 5 to 8 for a period of not more than 5 minutes.

The use of a catheter with an imperforate tip soluble in body fluids is especially advantageous when occasional irrigation is to be carried out. In such procedures, substantial amounts of cellular debris and disconnected fragmented tissue are frequently dislodged which do not pass freely through the eyes of a conventional cather tip, but tend to collect in and around the eyes to impede or occlude the desired drainage function.