Drainage Control

Abstract

A method and apparatus for urinary drainage in which the normally closed system includes an adjustable upward course between the bladder and the downward course leading to a drainage receptacle, with the provision of venting means in the form of a one-way valve (e.g., flutter valve) in the upper portion of the system designated to admit atmospheric air cyclically when the flow of liquid in the downward course causes negative pressure in the upward course, whereby the system is periodically emptied and permitted to refill in a simulation of normal physiological filling and emptying of the bladder.

Parent Case Text

This application is a continuation-in-part of application Ser. No. 473,917, filed July 22, 1965 and now abandoned.

Description

Heretofore, it has been a common hospital procedure to obtain continuous drainage of urine from the urinary bladder by means of a catheter passed transurethrally and retained in the bladder by a number of standard and conventional devices. It is usual practice to attach a relatively large bore, plastic drainage tube to the proximal end of the urinary catheter and lead this drainage tubing along a downhill path over the side of the bed into a collection bottle or bag which is placed below the level of the urinary bladder. Such an apparatus when functioning properly creates a syphon effect in the catheter only to the level of the connection between the catheter and the drainage tube. However, a syphon effect is not obtained in the drainage tube as the bore of the latter is large enough so that air bubbles pass up the drainage tube preventing a syphon action therein. With this arrangement, generally continuous drainage is obtained in that the bladder is always kept empty, there being no provision for automatic and periodic filling and emptying of the bladder.

There are two basic objections to this system. First, the urinary bladder is a hollow distensible organ which depends upon alternate filling and emptying to maintain the tone of its muscular walls. Also periodic filling and emptying of the bladder is one of the major methods or mechanisms by which the concentration of bacteria in the bladder is kept at low levels. This mechanism depends on dilution of the bacteria existing in the bladder with sterile urine from the ureters followed by periodic and complete emptying of the bladder. It has been demonstrated that if bacteria are injected into a normal bladder in large concentrations, the bladder is capable of clearing these organisms by this mechanism within approximately 24 to 48 hours. If the bladder is kept from emptying completely, though still allowed to expel portions of its contents periodically or continually, the growth of bacteria in the bladder may be of much magnitude that infection will ensue.

The second objection to the aforementioned conventional method is that most of the catheters used as indwelling bladder catheters do not conform to the contracted shape of the bladder so that "Foley tip necrosis" of the dome of the bladder, a syndrome well known to urologists and pathologists, may result. It is felt by some that this pressure ischemic ulcer of the dome of the bladder is the portal by which bacteria enter to infect the bladder wall. Such infections, common in patients with indwelling catheters, are caused when the dome of the bladder collapses and falls, or is drawn, down over the indwelling catheter, particularly over the tip of the catheter.

There are several pitfalls in the use of the aforementioned conventional drainage system which are very commonly encountered in hospitals and which accentuate this situation. For example, the drainage tube may be placed below the surface level of urine in the collection bottle or bag. Under these circumstances, the drainage tubing may fill with urine and exert a strong and continuous syphon action in the bladder. This draws the dome of the bladder down over the indwelling catheter and over the tip thereof very much enhancing the formation of pressure ulcers in the dome of the bladder. Also it has been demonstrated many times that submerging the end of the drainage tube in the urine will allow bacteria to swim up the slowly draining fluid in the drainage or connecting tubing and infect the bladder by that route.

Another pitfall of the aforesaid conventional drainage system is that if the drainage tubing is not led straight from the indwelling catheter to the collection bottle, urine will collect to form pockets in any loops which may be in the tubing, thereby causing a back pressure in the bladder with a resulting residual stagnant pool of urine therein. Such residual pooling is well known to hasten the onset of infection.

It is an object of the present invention to avoid the aforesaid difficulties of known prior art practices by providing a method and apparatus for drainage of fluids from the body with an indwelling bladder catheter or the like which automatically and periodically collapses and drains the cavity by syphon action, insuring its complete emptying, and which then allows the cavity to distend and collect the fluid once again to a predetermined pressure before recycling, the syphoning action essentially emptying and clearing the drainage tubing of fluid at the end of each syphoning cycle.

A further object is to provide a drainage system which reduces the chances of introducing bacteria into the body, which simulates physiological drainage of the cavity, and which functions in such a way as to maintain the muscular tone of the walls of the cavity.

Another object is to provide a drainage system which is relatively inexpensive and which utilizes a simple and uncomplicated arrangement readily adapting it for use by personnel already having training with conventional apparatus.

A further object is to provide certain improvements in the form, construction, arrangement and material of the several elements wherein the above-named and other objects may effectively be attained.

A practical embodiment of the invention is shown in the accompanying drawings wherein:

FIG. 1 represents an elevational view showing the overall arrangement of a drainage system vented as proposed herein;

FIG. 2 represents a detailed longitudinal section through the syphon control valve to which is attached the drainage funnel of a catheter and the upper end of a drainage tube, the position of the distal end of the catheter in the patient's bladder being indicated diagrammatically;

FIG. 3 represents a section on the line III-III of FIG. 2;

FIG. 4 represents a plan view of a simple form of tube fastener, and

FIG. 5 represents a detail section on the line V-V of FIG. 1, indicating how the tube fastener is used.

Referring to the drawings, FIG. 1 shows a patient lying in a standard hospital bed with a conventional indwelling catheter 1 in situ. Between the catheter and the drainage tube 2 (leading to a collection receptacle 3) is installed a syphon control valve 4, one arm of which is engaged in the drainage funnel 5 of the catheter while the tube 2 is fitted in the opposite arm and bonded thereto. The valve body may conveniently be made of a nontoxic rigid thermoplastic material having the general configuration of a T-connector. The tube 2 is preferably led under the patient's leg, but is here shown over the thigh as a matter of convenience in illustration and because such a location is common practice.

The sidearm 6 (FIG. 2) is provided with an inwardly projecting flutter valve 7, preferably of rubber and of a type known as a "golden gate" valve, formed from a section of flat tubing the upper end of which is stretched outward and snapped over the rim of the sidearm; although equivalent devices of other materials and installed in other manners might be substituted. A filter disc 8 of material having a pore size sufficient to filter out airborne bacteria covers the valve 7, the filter material being sufficiently open to allow passage of air at very low vacuums, on the order of 1 inch of water, but at a restricted rate for reasons explained below. The filter and valve are held firmly in place on the arm 6 by means of a retaining cap 9 of rigid plastic or metal, the lower edge of which may engage in a groove 10 around the arm 6 to seal the filter and valve on the arm. The valve permits the passage of air from the atmosphere into the syphon control valve bore 11 when the pressure therein is less than atmospheric, but prevents the flow of urine from the bore 11 outward when the pressure is greater than atmospheric; the inertia of the valve and filter being minimal (1 inch of water) for opening and the valve closing by its own inherent elasticity at atmospheric pressure.

In FIG. 2 there is shown somewhat diagrammatically the kidney 12, ureter 13 and bladder 14 of the patient, a Foley catheter 1 being retained in the bladder by means of the balloon 15.

Since the catheter is normally available in its own individual sterile package, the valve and drainage tube will preferably be sealed, sterile, in a suitable plastic bag or other convenient container, the tapered arm of the valve being covered by a simple plastic cap (not shown) to protect its sterility while the system is being set up. On removing the assembly from its package, the user first attaches the pinnacle point 16 of the drainage tube to a support 17 (e.g., an I. V. pole) at a height of approximately 6 inches above the level of the patient's bladder by means of the tube fastener 18. The fastener 18 may conveniently be a known "rattail" band (FIG. 4) which is used by bending the middle portion around the tube 2, passing the small end through the nearest hole 19, around the pole 17 and back through the end hole 20 so that the pole 17 is firmly gripped in the loop between the holes. The lower end of the drainage tube 2 is then led to a suitable receptacle 3 (shown conventionally as a bottle, for which known types of plastic bags may be substituted) on or near the floor. Assuming that the patient has already been catheterized, the syphon control valve protective cap (not shown) is removed and the tapered end of the syphon control valve 4 is inserted into the funnel of the catheter 1. Urine is produced by the kidney 12 and flows down the ureter 13 into the urinary bladder 14 and thence through the catheter 1, through the bore 11 of the syphon control valve 4 and into the drainage tube 2.

In order for the urine to reach the pinnacle point 16 of the drainage tube which is disposed, for example, 6 inches above the level of the urinary bladder 14, 6 inches of water pressure will have to be generated by the excretion of urine into the bladder. To reach this pressure, the bladder must be distended and hence increase in volume of urine contained. When the hydrostatic pressure of the urine in the bladder reaches +6 inches of water, urine will spill over the pinnacle point 16 of the drainage tube 2 and commence a gravity induced syphon in the downward section 2' of the drainage tube. This syphon action will produce a negative pressure throughout the drainage conduit equivalent to the vertical length of the downwardly disposed drainage tube 2' less the vertical length of the upwardly disposed length of drainage tube (up to point 16) also less, of course, the friction in the system for as long as there is flow in the system.

For example, if the pinnacle point 16 of the drainage tube is placed a vertical distance of 6 inches above the bladder and the end of the downward section 2' of the drainage tube is placed a vertical distance of 24 inches below the bladder, then the net maximum syphon pressure in the system will be -18 inches of water (-24 inches + 6 inches = -18 inches). Actual pressures within the actively syphoning system will depend also upon the rate of flow and the friction in the tubing. But when the bladder has been completely emptied of urine, flow slows and the pressure at all points in the system approaches equivalency and the net maximum syphon negative pressure. This negative pressure is, of course, exerted in the syphon control valve bore 11 through the filter 8. The air flows into the bore 11 and then through the tube 2 past the pinnacle point 16 and down the tube 2'. The flutter valve 7 and filter 8 are so designed that the entry of air is restricted sufficiently to permit the bladder to be substantially completely emptied before the syphon is broken, the air continuing to flow into the system through the valve 4 until all of the urine has been emptied out of both upward course and the downward course of the tubing and the pressure in the bore 11 has risen again to atmospheric pressure. The valve 4 then closes and the system is ready for recycling.

The trigger pressure of the syphon is purely a function of the height of the pinnacle point 16. The greater the vertical distance the pinnacle point is above the bladder, the higher the pressure in the bladder must become before the syphon begins. Since the volume of the bladder, is a function of the pressure of the of the urine it contains, by adjusting the pressure that must be reached before drainage, it is possible to control the maximum distention of the bladder.

An important convenience of the system disclosed herein is that it can be used by ambulatory patients who need merely attach the pinnacle point 16 to the patient's hospital gown (as by means of a safety pin) at an appropriate vertical distance above the bladder, the receptacle 3 being, in this case, of a portable type.

As previously mentioned, the invention is particularly adaptable for draining the urinary bladder and has been so described in connection with the illustrated embodiment. It will be understood however, that the invention has other applications, for example, in draining the stomach with a Levin tube.

It will be understood that various changes may be made in the form, construction and arrangement of the several parts without departing from the spirit and scope of the invention and hence we do not intend to be limited to the details shown or described herein except as the same are included in the claims or may be required by disclosures of the prior art.

Claims

What we claim is:

1. The method of draining a body cavity of liquid to which the body normally supplies said liquid comprising providing a conduit means leading from said body cavity, said conduit comprising a length of tubing, supporting an intermediate section of said drainage tube at an elevated disposition to define a pinnacle in which an upstream side of said tubing leads from said body cavity generally upwardly to said pinnacle and a downstream side of said drainage tubing leads generally downwardly from said pinnacle to said receptacle, providing an air vent valve operable when open to admit air to said upstream side and when closed to preclude communication between the atmosphere and said upstream side, draining the liquid from said cavity to said upstream side of said tubing while maintaining said air vent valve in a closed position, allowing the liquid to fill said upstream side and thereafter to flow beyond said pinnacle into said downstream side, inducing a syphoning action in said tubing by said flow, opening said air vent valve in response to the reduction of pressure in said upstream side of said tubing resulting from the syphoning action, introducing air at a controlled restricted rate into said upstream side through said air vent valve to overcome said reduction in pressure, and restoring said tubing to atmospheric pressure upon completion of the syphoning action, emptying said tubing and said body cavity by said syphoning action, and repeating the above cyclically to periodically drain said cavity.

2. Apparatus for draining a body cavity of liquid to which the body normally supplies said liquid comprising conduit means leading from said body cavity to a receptacle, said conduit comprising a length of drainage tubing, means supporting an intermediate portion of said drainage tubing at an elevated disposition to define a pinnacle in which an upstream section of said tubing leads from said body cavity generally upwardly to said pinnacle and downstream section of said drainage tubing leads generally downwardly from said pinnacle to said receptacle, an air vent valve in said upstream section operable when open to admit air to said upstream section and when closed to preclude communication between the atmosphere and said upstream section, said valve closing upon an increase in pressure in said upstream section above atmosphere and opening upon a decrease in pressure in said upstream section below atmosphere, said valve being in said closed position while liquid drains from said cavity to said upstream section and opening in response to the reduction of pressure below atmosphere in said upstream section resulting from the syphoning action as the liquid fills said upstream section and flows past said pinnacle to said downstream section, whereby said valve admits air into said upstream section to overcome said reduction in pressure and restore said tubing to atmospheric pressure upon completion of the syphoning action.