GB2389534A

GB2389534A - Improvements in and relating to catheter control

Info

Publication number: GB2389534A
Application number: GB0226436A
Authority: GB
Inventors: Margaret Pamela Richardson; Philip Richardson
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-06-14
Filing date: 2002-11-13
Publication date: 2003-12-17
Also published as: GB0213596D0; GB0226436D0

Abstract

Apparatus 1 for controlling the operation of a catheter, the apparatus including an inlet 2 for receiving the output end of a catheter and an outlet 3 for discharging liquid received from the catheter, valve means 7,7ab between the inlet and the outlet for controlling the flow of liquid through the apparatus. Sensing means 8,9 for sensing one or more properties of the liquid in the apparatus, and control means (10,12,13; Fig 2) for controlling operation of the valve means in response to a sensed property of the liquid, such as pressure, and/or in response to a predetermined criteria, such as a time interval having elapsed. The application also discloses a flexible tube 1a which is intended to be disposable and having deformable side walls to allow regulation of fluid flow therethrough. A slow-release sterilisation pellet 15 for insertion into the flexible tube is also disclosed. The pellet is typically in the form of an O-ring or annular in shape.

Description

IMPROVEMENTS IN AND RELATING TO

CATHETER CONTROL

Catheter associated urinary tract infections account for a large number of 5 hospital acquired infections. Forty four per cent of hospitalized patients with catheters have been found to develop significant bacteruria within 72 hours of catheterization. Some of these infections result in complications including pylonephritis, epididymitis, abscess formation and chronic renal failure. This leads to catheter blockage which represents one of the most common 10 complications associated with such infections.

Attempts have been made to improve the methods for the prevention, control and treatment of catheter associated infections such as by the use of a closed drainage system, strict observance of aseptic techniques in the handling 15 of catheters, the use of cranberry juice drinks and the production of catheters containing antimicrobial substances.

Once an indwelling device, catheter or prosthesis becomes infected, the associated micro-organisms show remarkable resistance to both host defences 20 and antimicrobial agents. Therefore, although ail of these procedures have been shown to either reduce the incidence of or delay the onset of catheter associated infection they have been unable to eradicate it.

Another commonly used method to combat infections and related blockage complications is irrigation of the urinary catheter with various solutions.

However, the application of numerous agents using a variety of irrigation methods has resulted in a confusing picture, both in terms of their efficiency and 5 clinical applications.

The building up of encrustation and urease activity results in an increase in urine alkalinity, and it has been shown in a study examining the pH encrustation that patients with a mean urinary pH below 6.8 had minute traces of 10 encrustation, while patients above pH 6.8 had considerably more.

It has been found that periodic exercise of the bladder by allowing it to fill and empty normally is beneficial in an otherwise continuous drainage regime in that normal bladder function is preserved and the average pH of the urine is 1 5 lowered.

Catheter encrustation is often found associated with high urinary pH and the practice of testing the urine for pH level to identify patients most at risk of catheter encrustation has been shown to be beneficial in the management of 20 such patients to avoid encrustation.

The present invention addresses the problems associated with catheter infection by the provision of an apparatus which monitors and controls the catheter. 5 According to the invention there is provided apparatus for controlling the operation of a catheter, the apparatus including an inlet for receiving the output end of a catheter and an outlet for discharging liquid received from the catheter, valve means between the inlet and the outlet for controlling the flow of liquid through the apparatus, sensing means for sensing one or more properties of the 10 liquid in the apparatus, and control means for controlling operation of the valve means in response to a sensed property of the liquid, such as pressure, and/or in response to a predetermined criteria, such as a time interval having elapsed.

Preferably, the inlet for receiving the output end of the catheter and the 15 outlet for discharging it is a resilient tube, between the inlet end and outlet end of which is disposed the valve means, which tube and valve means may be integral. The valve means may conveniently comprise deformable walls of the tube which may be pressed together to thereby wholly or partially close the tube to thereby prevent or inhibit, as the case may be, the flow of liquid from the 20 outlet end of the tube.

The invention therefore provides a device for controlling and managing the operation of a catheter and the measuring, recording, assessing, and interrogation of the physical and chemical parameters of the contents of the

catheter, including the downloading of such information to a suitable memory, such as to a computer for storing, analysing etc such information and the subsequent controlled dispensation of appropriate drugs or medicines into the catheter. The valve means may be actuated by any suitable means, such as hydraulic, pneumatic, mechanical or electrical means.

The means for assessing, measuring, recording, interrogating and 10 downloading information relating to the contents of the urinary bladder during catheterization may conveniently be electronic.

The means for dispensing appropriate drugs or medicines may be activated electronically or manually.

Where the catheter control unit is used to allow urine to be extracted from the bladder of a person, it is preferred that the apparatus is constructed in two parts: 20 a) A one use disposable tube with a valve or valves which come into contact with urine, and b) A reusable electronic control unit which operates the valve or valves, measures pressure, pH value of the urine and any other desired

characteristic, and is capable of recording and assessing, downloading and interrogating such data etc. Where two or more valves are used it is preferred that chambers be 5 provided between them.

Means for sterilising/cleansing the valve chamber/chambers may be provided. 10 Means for measuring, recording and altering the pH value of the urine may be provided.

The apparatus may conveniently be powered by a renewable or rechargeable battery.

The electronic means for storing, measuring, assessing, recording and early warning may be one or more microchips.

The disposable tube and/or the reusable part of the apparatus may be 20 provided with a means for attaching it to the catheter and the drainage bag.

The disposable tube and the reusable part of the apparatus may be provided with an automatic means of disconnection from the drainage bag if the

drainage bag/tube is accidentally pulled. This may be by means of a link which is arranged to be broken when subjected to a predetermined longitudinal force.

In use the disposable tube and valve or valves may fit into the reusable 5 electronic unit and be controlled by an electronic chip. When assembled together into one unit (collectively "urinary control apparatus") the valve unit and reusable electronic unit can then automatically control the flow of urine from the bladder and monitor and record desirable information for interrogation. A manual override may be applied to control the flow of urine from the bladder if 1 0 desired.

The urinary control apparatus may be designed to fit onto the open end of a urinary catheter such as a Foley catheter after the Foley catheter has been installed in the usual way in the bladder. A standard drainage bag may then be 15 fitted to the outlet end of the tube if desired and draining of the bladder can take place in the usual way.

The urinary control apparatus, when supplied with a first electronically controlled valve, which desirably will be placed above the second electronically 20 controlled valve on the catheter side of the control unit, can be used to regulate the flow of urine from the bladder when the sensing means, which may be a pressure switch, detects there is a predetermined pressure of urine in the bladder.

At the predetermined pressure/time interval the first electronically controlled valve will open and let out the urine from the bladder, after which it will close and urine will once again collect in the catheter tube and the bladder until the pressure/time builds up or time elapses ready for the next evacuation. Urine 5 discharged through the urinary control unit may be collected in a standard collecting bag which can be fitted to the distal end of the urinary control apparatus. When urine passes through a first open valve it may be monitored by the 10 electronic unit, e.g. the pH value of the urine may be recorded as well as the frequency and volume etc. Any disadvantageous information recorded may activate an audible warning so that remedial action may be taken.

The urinary control apparatus may be supplied with a second valve which 15 is placed below the first valve on the drainage bag side. This provides a barrier chamber between the two valves in which e.g a slow release antibacterial compound or the like may be sited. At a predetermined pressure/time interval the first and second valves open and let out urine from the bladder, after which they close and urine will once again collect in the catheter tube and the bladder 20 until the pressure builds up/time elapses ready for the next evacuation. When the second valve is closed the slow release antibacterial compound will then collect in the barrier chamber to provide a barrier between the drainage bag and the urinary control apparatus. This helps to prevent bacteria travailing up into the first chamber and the catheter lumen. The provision of a chamber with an

antibacterial compound or the like can therefore help to prevent infection of the bladder. An electronic control unit can be used to control the operation of the 5 valves and measure the physical and chemical characteristics of the urine as it passes through the unit. This will supply the data which is required for the early identification of adverse conditions affecting the patient and the catheter e.g. if the pH of the urine is monitored and recorded on a regular long term basis it is possible to identify those patients that are at risk of catheter encrustation and the 10 subsequent risks of catheter blockage, trauma and infection to the wearer of the catheter. For measuring phi values various means are known in industry, such as by the use of electrodes. Alternatively, litmus paper or other pH reactive 15 materials may be used.

The urinary control apparatus aspect of the current invention may also be beneficially provided with a flow meter which may preferably be of a Venturi type positioned and incorporated within the resilient tube forming part of the 20 apparatus. Preferably, the pressure sensors necessary for the operation of the flow meter are electronic.

The urinary control apparatus may also be beneficially provided with means for measuring the colour and turbidity of the urine, this being achieved by using a light source projected e.g. through a thin-wall substantially transparent section of the disposable tube part of the apparatus onto a light sensor, such as 5 an electronic light sensor.

The urinary control apparatus may also conveniently be provided with means for back flushing of the catheter which may be achieved via a sealable port on the disposable tube section of the apparatus. Alternatively, back flushing 10 may be provided by the provision of means for generating a short term reverse flow of liquid, including urine in the form of a pulse within the catheter. The pulse may be rapidly repeated to loosen and dislodge encrustation at the tip of the catheter and so prevent build-up and subsequent blocking of the catheter Preferably, the means for providing back flushing pulses is by rapidly repeated 15 compression and relaxation of the walls of the resilient tube.

The urinary control apparatus may also be beneficially provided with a sterilising light source and means for dispensing sterilising light within the catheter and drainage bag system. Preferably, the sterilising light source 20 produces ultraviolet light which may conveniently be dispensed within the catheter and drainage bag system by means of a 'leaky' type of optical fibre, in which case it is further preferred that the optical fibre be loosely inserted in the lumen of the catheter.

The benefits of placing the urinary catheter control apparatus between the catheter and the storage bag are as follows: a) the control apparatus can fit between an e.g. standard Foley 5 catheter or standard supra-pubic catheter and standard drainage bag such that no, or minimal, user education is necessary; b) the bladder can be controlled i.e. filled and emptied without any patient intervention; c) the apparatus is suitable for use for a patient who is not conscious or for the elderly confused; d) drainage of the bladder can be monitored and data relating to urine 15 characteristics measured and recorded; e) bladder drainage can be made automatic such that normal function of the bladder Is maintained; 20 f) the problems associated with infection and crystallization experienced with continuous drainage can be substantially reduced;

g) the provision of a barrier chamber and the regular flushing of the catheter can mean the possibility of less infection transmitting through the catheter lumen; and 5 h) there can be two seals between the storage bag and the catheter i.e. one at the catheter output end (the input of the urinary control apparatus) and the one way seal adjacent to the collection, which is usually installed to prevent backflow from it to further reduce the incidence of infection.

Substantially complete control of bladder drainage may therefore be possible through the use of the urinary control apparatus of the invention Bladder drainage can be continuous or intermittent, according to requirements.

The control apparatus can be used for all catheters and drainage bags since the 15 attachments are usually universal. The urinary control apparatus can be made fail-safe in that it can give warning of failure. In such an event the apparatus can be removed simply by pulling it out of the catheter opening and the bag opening in the same way as the drainage bag fitting is removed from the catheter. The catheter may then be connected to the drainage bag in the usual way and 20 bladder drainage resumed without the urinary control apparatus in place.

In an alternative embodiment of the invention the storage bag may not be attached to the urinary control apparatus but instead the valve or valves are operated manually or electronically in response to pressure sensing/time interval

sensing if desired. This enables the patient to control and monitor the discharge of urine without the need for carrying a drainage bag.

The urinary catheter control apparatus can therefore be versatile in that a 5 patient in hospital may be fitted with a standard catheter, a urinary control apparatus and a drainage bag. The urinary control apparatus may then be operated in conjunction with a drainage bag whilst the patient requires such treatment. However, when the patient is in a position to be discharged from hospital, or does not require a drainage bag any longer, after some simple user 10 education, the drainage bag may be removed and the catheter and urinary control apparatus left in place. The patient will then be able to operate the discharge of urine manually through the urinary control apparatus and interrogate the electronic monitor to ascertain the pH level etc. of the urine. If the pH level of the urine needs to be altered an appropriate solution may be 15 discharged into the catheter through the electronic control apparatus.

The invention will now be described. by way of example only, with reference to the accompanying drawings, in which: 20 Figure 1 is a general arrangement diagram of an inlet and outlet tube, associated valve means and sensing means of urinary catheter control apparatus;

Figure 2 is a general arrangement diagram of the assembled urinary catheter control apparatus of the invention; Figure 3 is a general arrangement drawing showing the plan view of the 5 apparatus of Figure 2; Figure 4 is a general arrangement diagram of the tube of Figure 1 modified to provide a double valving and sterilization chamber together with a link arranged to be broken when subjected to a predetermined longitudinal force; 10 and Figure 5 is a general arrangement diagram of urinary catheter control apparatus of the invention attached to a typical urinary catheter and a typical urine collection bag.

Referring firstly to Figure 1, this shows part of a urine catheter control apparatus according to the invention which includes a resilient tube shown generally at 1, which may be made of e.g. silicone. The tube 1 includes at one end a frusto-conical male push connector 2 sized to fit into the cone connection 20 end of a typical urinary catheter (not shown). At the other end of the tube 1 is a frusto-conical female connector 3 sized to allow the insertion and retention of a tube from a urine collection bag (not shown). Adjacent to the male connector 2 is a generally disk-shaped location flange 4 provided with a flattened region 5 on

one side thereof so as to locate the tube 1 correctly within the urine collection apparatus in a manner to be described.

In the mid-region 6 of the tube 1 the walls thereof are deformable to the extent that a pair of actuators 7, when moved towards each other in the direction 5 shown arrowed to the position shown in broken line can squeeze the tube 1 in this region sufficient to effect a valve arrangement by which flow of liquid therethrough may be prevented or inhibited.

In order to sense the pressure in the tube 1 a pair of pressure sensors 8 10 can be disposed in the manner as shown to lightly bear against the tube 1 in this region so that the internal pressure of liquid in the tube can then be determined to detect build-up of urine in the bladder of the catheter wearer when the actuators 7 are closed to their position shown in dotted outline.

15 Above the pressure sensors 8 are a pair of electrical contacts 9 emanating from a pH transducer (not shown) built into the wall of the tube 1.

This can therefore be used to sense the pH of liquid in the tube via electronic means in a manner to be described.

20 Referring now to Figures 2 and 3, there is shown the general arrangement of a catheter control apparatus in the form of urine catheter control apparatus comprising, in this embodiment, a housing 10 for containing electronic components including control components for the apparatus, as well as the tube

1, this being retained in place in the housing 10 by the flanged disk 4 being received within a correspondingly shaped recess in the housing 10 in a manner more clearly shown with reference to Figure 3, in which it will be seen that a hinged door 11 can be used to trap the disk 4 and hence the tube 1 in position 5 by bearing up against the flattened portion 5.

A graphic display 12 is provided on a front face of the housing 10, which may be an LCD display, to give a visual data output of the apparatus, and control buttons shown generally at 13 are provided for actuating electronic 10 components within the housing 10, such as for sensing, actuating and recording purposes. Figure 4 shows a tube shown generally at 1a similar to the tube 1 of Figure 1 but in this instance instead of having room for a single valve means 15 including a single pair of actuators 7 as shown in Figure 1, there are instead two pairs of actuators 7a and 7b displaced axially along the length of the middle portion 6 of the tube 1a, corresponding other parts of the arrangement to that shown in Figure 1 having corresponding numbering. As can be seen, when the pairs of actuators 7a and 7b are moved inwardly in the direction shown arrowed 20 to the position shown in dotted outline a chamber 14 is formed between them into which may be inserted during the manufacture of the tube 1a a pellet 15 (also shown in dotted outline), such as in the shape of an o-ring, of a slow dissolving material capable of providing a sterilising action to any liquid in the chamber, the pellet being formed by commonly available bleaching or sterilising

agents. Similarly, one or more other pellets may be releasably held in the tube 1a above the actuator 7a and may be capable of e.g. releasing acidity into the tube 1a and hence into the catheter lumen to help counter the build-up of alkalinity within the catheter resulting from urease bacteriological activity. The 5 rate of dissolving may be controlled externally as required by providing, for example, a localised heating element in this region of the tube 1 a with the pellet 15 being designed to release more or less acidity by varying the heating of the tube 1a and hence the pellet 15 in this region.

10 As a safety measure a breakable link 16 is provided above the female connector 3 and below the mid-section 6 of the tube 1a, the link 16 having a weakened portion designed to snap when subjected to a pre- determined longitudinal force caused by accidental pulling or tension on the drainage bag and associated tubing.

In Figure 5 there is shown a general arrangement of the urinary control apparatus of this embodiment of the invention attached by its male connector to the female connector 17 of a typical Foley-type urinary catheter 18, and is also attached by its female connector to the tube 19 (only part of which is shown) of a 20 typical urine collection bag 20.

In a second embodiment of the invention there is provided a means for controlling and managing an intravascular device. In this embodiment, the electronic control circuitry and associated tube may be used to measure internal

pressure at the site of an intravascular installation and if pressure rises beyond a set limit, e.g. the onset of ""issuing", one or more valves may operate automatically to limit the flow and thus reduce the pressure in the intravascular device. At the same time, a warning sound or light may be activated. In this embodiment it is preferred that the pressure sensor be positioned after the valve or valves in order to sense the pressure in the intravascular device, which may typically be a venflon.

Claims

1. Apparatus for controlling the operation of a catheter, the apparatus including an inlet for receiving the output end of a catheter and an outlet for 5 discharging liquid received from the catheter, valve means between the inlet and the outlet for controlling the flow of liquid through the apparatus, sensing means for sensing one or more properties of the liquid in the apparatus, and control means for controlling operation of the valve means in response to a sensed property of the liquid, such as pressure, and/or in response to a predetermined 10 criteria, such as a time interval having elapsed.

2. Apparatus according to claim 1 further characterized in that the inlet for receiving the output end of the catheter and the outlet for discharging it is a resilient tube, bet Been the inlet end and outlet end of which is disposed the valve means.

15

3. Apparatus according to claim 1 or claim 2 further charactensed in that the tube and valve means are integral.

4 Apparatus according to claim 2 or claim 3 further characterized in that the valve means comprises deformable walls of the tube which may be pressed together to thereby wholly or partially close the tube to thereby prevent or inhibit, 20 as the case may be, the flow of liquid from the outlet end of the tube.

5. Apparatus according to any preceding claim for use in allowing urine to be extracted from the bladder of a person, further characterized in comprising two parts, the first part being in the form of a one use disposable tube with valve means which come into contact with urine. and the second part comprising a

reusable electronic control unit for operating the valve means, measuring properties of the urine such as pressure, pH value and any other desired characteristic, the control unit also being capable of recording and assessing, downloading and interrogating such measured data.

5

6. Apparatus according to claim 5 further characterized in that where the valve means comprises two or more valves, chambers are provided therebetween.

7. Apparatus according to claim 6 further characterized in that means are provided for sterilising/cleansing the or each chamber between two or more 10 valves.

8. Apparatus according to claim 7 further characterized in that the means for sterilising/cleansing comprises a slow-release anti-bacterial compound or the like.

9. Apparatus according to any one of claims 5 to 8 furler characterized in 15 that means for measuring, recording and altering the pH value of the unne Is provided.

10. Apparatus according to any one of claims 5 to 9 further characterized in that the disposable tube and/or the reusable part of the apparatus is provided with means for attaching it to the catheter and a drainage bag.

20

11. Apparatus according to any one of claims 5 to 10 further characterized in that the disposable tube and the reusable part of the apparatus is provided with an automatic means of disconnection from the drainage bag it the drainage bagitube is accidentally pulled.

12. Apparatus according to claim 11 further characterised in that the automatic means of disconnection is by means of a link adapted to be broken when subjected to a predetermined longitudinal force.

13. Apparatus according to any one of claims 5 to 12 further characterised in 5 that the disposable tube and valve means are adapted to fit into the reusable electronic unit.

14. Apparatus according to claim 13 further characterised in being provided with a manual override to control the flow of urine from the bladder.

15. Apparatus according to any one of claims 5 to 14 furler characterised in 10 that a first electronically controlled valve is used to regulate the flow of urine from the bladder when the sensing means detects there is a predetermined pressure of urine in the bladder.

16. Apparatus according to claim 15 further characterised in that the sensing means comprises a pressure switch.

15

17. Apparatus according to any preceding claim further characterised in that the valve means comprises a first valve at the inlet end of the apparatus for receiving liquid output from the catheter, and a second valve at the outlet end of the apparatus, the space between the first and second valves defining a chamber in which e.g. a slow release antibacterial compound or the like may be 20 sited.

18. Apparatus according to claim 17 further characterised in that an electronic control unit is used to control the operation of the valves and measure the physical and chemical characteristics of the liquid therebetween.

19. Apparatus according to claim 18 when used for urinary control further characterised in being provided with a flow meter.

20. Apparatus according to claim 19 further characterised in that the pow meter is of the Venturi type.

5

21. Apparatus according to any one of claims 5 to 20 further characterised in being provided with means for measunng the colour andJor turbidity of the urine.

22. Apparatus according to claim 21 further characterised in that the means for measuring the colour and/or turbidity of the urine is a light source projected through the urine onto a light sensor and associated measuring circuitary.

10

23. Apparatus according to any one of claims 5 to 22 further characterised in that means for back flushing of the catheter are provided.

24. Apparatus according to claim 23 furler characterised in that the means for hack flushing of the catheter is via a sealable port on the disposable tube section of the apparatus.

15

25. Apparatus according to claim 23 further characterised in that the means for back flushing of the catheter is by the provision of means for generating a short term reverse flow of liquid in the form of a pulse within the catheter.

26. Apparatus according to claim 25 further characterised in that the means for providing back flushing pulses is by rapidly repeated compression and 20 relaxation of the walls of the resilient tube.

27. Apparatus according to any one of claims 5 to 26 further characterised in that a sterilising light source is provided.

28 Apparatus according to claim 27 further characterised in that the sterilizing light source produces ultraviolet light.

29 Apparatus according to claim 27 or claim 28 further characterised in that the sterilising light source is dispensed within the catheter by means of a "leaky" type of optical fibre.

30. Apparatus according to claim 29 further characterised in that the optical 5 fibre is loosely inserted in the lumen of the catheter.

31. Apparatus according to any one of claims 5 to 30 further characterised by being adapted to be operated without a liquid storage bag, such as a urine storage bag in response to pressure sensingAime interval sensing, either manually or electronically.

10

32. A disposable tube having a liquid inlet end adapted for insertion onto or into a liquid outlet end of a catheter, the tube having resiliently deformable sidewalls by which flow of liquid from the catheter therethrough may be controlled via sidewall pressure thereon, characterised in that the tube is adapted to be received within a housing of urinary control apparatus according 15 to any one of claims 5 to 31.

33 A tube according to claim 32 further characterised in that it includes location means enabling it to be correctly oriented within the housing.

34. A tube according to claim 33 further characterised in that the location means comprises a flange having a flattened region adapted to rest against a 20 correspondingly flattened region of the housing.

35. A tube according to any one of claims 32 to 34 further characterised in that it includes an integral pH transducer and associated electrical contacts by which the pH of liquid passing therethrough may be monitored.

36 A tube according to any one of claims 32 to 35 further characterized in that it includes a weakened region in the form of a breakable link adapted to snap when subjected to a predetermined longitudinal force, relative to the major axis of the tube.

5

37. A slow release pellet adapted to be inserted within a tube according to any one of claims 32 to 36, the pellet comprising or including a sterilising andlor cleansing agent.

38. A pellet according to claim 37 further characterized in that it is in the form of an oaring dimensioned to fit within the tube and allowing liquid to flow 1 0 therethrough.

39. Apparatus substantially as hereinbefore described with reference to Figures 2, 3 and 5.

40. A tube substantially as hereinbefore described with reference to Figures1 or4.