GB2395128A

GB2395128A - Catheter control device

Info

Publication number: GB2395128A
Application number: GB0226536A
Authority: GB
Inventors: Diana Hodgins; Dave Ashby
Original assignee: EUROP TECHNOLOGY FOR BUSINESS; European Technology for Business Ltd
Current assignee: EUROP TECHNOLOGY FOR BUSINESS; European Technology for Business Ltd
Priority date: 2002-11-14
Filing date: 2002-11-14
Publication date: 2004-05-19
Anticipated expiration: 2022-11-14
Also published as: GB2395128B; GB0226536D0

Abstract

A control device 41 preferably for a urinary catheter 2 includes an inlet port 11, an outlet port 12 connected with a urine collection receptacle 13, a flow conduit 14 and a normally closed valve 15, responsive to a timer 17 and optionally a pressure sensor 21 to open and close the valve. The pressure sensor may override the timer to open the valve 15. The bladder drainage and refill periods as set by the timer may be reprogrammable via interface 33. The device may also include a pH sensor 44, a flow meter 45, a manual overrride switch 35 to open the valve and a data transmission output interface.

Description

23951 28

URINARY DRAINAGE CATHETER

The present invention relates to urinary catheters and in particular to control mechanisms for effecting the opening and closing of catheter valves to allow 5 drainage and filling of a bladder with which the catheter communicates.

A number of urinary catheter systems have been proposed in the art for patients who have a compromised ability to exert natural sphincter or detrusor control.

In a simple prior art arrangement, the patient may be fitted with a 'continuous

10 drainage' catheter that facilitates continuous drainage of the bladder into a bag or other suitable vessel. Such continuous drainage catheters have a well recognised disadvantage in that periodic filling and draining of the bladder (rather than continuous drainage) is highly desirable for a number of reasons.

These reasons include: (i) ensuring that bacteria are properly flushed from the 15 bladder; (ii) avoiding a build up of encrustations and other deposits within the catheter that will eventually block the catheter; and (iii) maintaining bladder tone. Therefore, a number of urinary drainage systems for ensuring periodic drainage 20 of the bladder have been proposed in the art. Many of these rely on a siphoning action (or 'tidal drainage') in which a build up of bladder pressure eventually triggers a siphon control valve to allow a siphon action to fully drain the bladder through the catheter to a collection vessel. A disadvantage of these systems is that they are generally suitable only for non-ambulatory patients, as 25 the siphon action requires appropriate relative height positioning of the various components of the system. An example of such a system is found in US 3598 124.

Some attempts have been made to overcome these disadvantages by the use of electronic or electromechanical control valves which rely on a pressure sensor to trigger drainage of the bladder through the catheter. To ensure complete drainage of the bladder once the pressure sensor has triggered opening of the 5 valve, various mechanisms are proposed to ensure that the valve remains open long enough for the bladder to drain.

For example, US 4230102 proposes an electromechanical system in which the valve is held open for a predetermined time period of one to five minutes. In a 10 further example, US 4865588 proposes a magnetic valve in which the closing pressure of the pressure actuated valve is less than the opening pressure.

These pressure actuated urinary drainage systems have several possible disadvantages. Firstly, it has been established that pressure build up in the bladder is not always a reliable trigger mechanism for drainage in some patients. This is because pressure in the bladder is not generally simply a function of the fill level of the bladder, and may be at least partially reliant upon the patient's 20 ability to apply pressure to the bladder via the bladder walls either voluntarily or involuntarily.

Secondly, the pressure actuated valves may be susceptible to abdominal and gravitational pressure, which in turn may be affected by the orientation, attitude 25 and / or movement of the patient when used in ambulatory systems.

Thirdly, in some patients, pressure receptors on the bladder wall may inappropriately cause the patient to exert pressure on the bladder wall sufficient

to trigger the pressure actuation of the valve even when the bladder is not yet filled to an appropriate level.

It is an object of the present invention to provide a urinary catheter control 5 valve that enables periodic filling and drainage of the bladder that is not wholly reliant upon pressure actuation.

It is a further object of the present invention to provide a urinary drainage system that can be made fully portable for use by ambulatory patients.

According to one aspect, the present invention provides a catheter control unit for regulating urine flow through a catheter comprising: an inlet port, including catheter connection means; an outlet port; 15 a fluid flow conduit extending between the inlet port and the outlet port, the conduit including a valve for controlling fluid flow through the conduit; and a controller, including a timer, the controller adapted to periodically open the valve upon sensing a predetermined opening condition, a least one opening condition being expiry of a predetermined fill time interval.

Embodiments of the present invention will now be described by way of example and with reference to the accompanying drawings in which: Figure l shows a schematic diagram of a urinary drainage system with a timer controlled valve; 25 Figure 2 shows a schematic diagram of a urinary drainage system with a timer controlled valve and pressure override; Figure 3 shows a schematic diagram of a urinary drainage system with a timer controlled valve and an integrated pressure control system and manual override;

Figure 4 shows a schematic diagram of a multi-sensor urinary drainage system with a timer controlled valve and an integrated pressure control system with flow rate data logging capability; Figure 5 shows a schematic diagram of the multi-sensor urinary 5 drainage system of figure 4 with a remote control unit; Figure 6 shows a functional block diagram of the catheter control valve unit of figure 1; and Figure 7 shows a functional block diagram of the catheter control valve unit of figure 5.

With reference to figure 1, there is shown a urinary drainage system I comprising a catheter 2 having a lumen 3 for conveying urine from an orifice 4 at a distal end of the catheter to a catheter outlet 5 at a proximal end of the catheter 2. Preferably, the catheter 2 includes an insertion mechanism (not 15 shown) for accurate placement of the catheter into the urethra or suprapubic of a patient, with the orifice 4 appropriately placed within the bladder. Various appropriate catheter insertion mechanisms are known in the art.

Preferably also the catheter 2 includes a retention mechanism for ensuring that 20 the catheter remains in position, with the orifice positioned correctly within the bladder. In the embodiment shown, the retention mechanism comprises a balloon 6 which can be inflated by way of an inflation device 7 communicating with the balloon by way of a tube or second lumen 8. It will be understood that various other catheter retention mechanisms are known to the person skilled in 25 the art, and other such mechanisms may also be used in practicing the present invention. Connected to the catheter outlet 5 is a catheter control unit 10 having an inlet port 1 I communicating with the catheter 2 and an outlet port l 2

communicating with a urine collection receptacle 13. The inlet port provides a suitable catheter connection mechanism for connecting a catheter. Exemplary connection mechanisms may be simply push fit connectors, twist connectors or screw threaded connectors or any other types known in the art.

The collection receptacle 13 may be any suitable vessel for receiving urine, such as a bottle, a bag that can be fixed to the patient for ambulatory use, or simply a pipe connected to a suitable drain in the case of a non-ambulatory patient. The collection receptacle may be completely omitted if the patient can 10 get to the toilet at appropriate times.

The catheter control unit 10 includes a fluid flow conduit 14 extending between the inlet port 11 and the outlet port 12 for conveying urine from the inlet port 11 to the outlet port 12, and therefore for conveying urine between a catheter 2 15 and a collection receptacle 13 if and when connected thereto.

The catheter control unit 10 includes a valve 15 of any suitable type for regulating the flow of urine through the conduit 14. Preferably, the valve is of a normally closed type, in which the conduit 14 is blocked to prevent fluid flow 20 therethrough. The valve 15 may be switched to an open configuration in which fluid flow through the conduit 14 is permitted, using an appropriate electrical, mechanical, electromechanical, pneumatic or other operating mechanism.

The valve 15 may also include a flow regulation setting in which the flow rate 25 of urine is regulated to a predetermined amount, although that is not an essential feature of the invention.

Coupled to the valve 15 is a controller 16 which facilitates the opening and closing of the valve 15 according to one or more criteria. The controller 16

may be of any suitable type, such as mechanical, electromechanical or electronic but in a preferred embodiment is a microprocessor based controller unit. 5 The controller 16 includes a timer 17 which may be preset to a predetermined time interval that is used to determine when the valve should open to allow drainage of the bladder through the catheter 2 and control unit 10. After a suitable drainage time, the catheter control unit 10 recluses the valve 15 to allow the patient's bladder to refill naturally. The refill time is determined by 10 the timer 17. The drainage time may also be determined by the timer 17. In a typical exemplary embodiment, a refill time may be in the range between 1 and 4 hours, while the drainage time may be 2 to 10 minutes, for example.

With reference to figure 2, an alternative arrangement of urinary drainage 15 system 20 provides a second condition for triggering the opening of the valve 15. The urinary drainage system 20 further includes a pressure sensor 21 for sensing urine pressure. Preferably, the pressure is sensed within the fluid flow conduit 14 of the catheter control unit 22, upstream of the valve 15, near the inlet port ll. However, other remote pressure sensing may be used, for 20 example, within the catheter 2 or even in the bladder itself. Such pressure sensors may comprise a pressure sensor located in the catheter 2 or bladder and communicating with the control unit 22 electrically, optically or by wireless link. Alternatively, a multi-lumen catheter 2 may include a pressure sensing lumen to deliver an indication of bladder pressure to a pressure sensor housed 25 within the control unit 22.

The pressure sensor 21 may override the timer to cause the valve 15 to open if the sensed pressure exceeds a predetermined threshold. In this manner, if a patient's bladder fills unusually quickly, the drainage system 20 will

accommodate this by emptying the bladder in advance of a normal fill time schedule. Preferably, the control unit 22 is adapted so that an unscheduled drainage event triggered by the pressure sensor 21 will result in a clearing of the elapsed time of the timer 17 so that it will restart the counting of the 5 predetermined fill time.

Preferably, the pressure sensor is configured to respond only to a pressure pulse greater than a predetermined minimum duration to avoid premature voiding due to coughs or other involuntary actions which could give rise to high 10 pressures of short duration.

Thus, in a general sense, the controller 16 is adapted to periodically open the valve upon sensing a predetermined opening condition, in which at least one opening condition is expiry of the predetermined fill time interval, under 15 control of the timer 17. in the embodiment of figure 2, a second opening condition is the sensing of urine pressure above a predetermined pressure level.

Similar to the arrangement of figure 1, after a suitable drainage time, the catheter control unit 10 recluses the valve 15 to allow the patient's bladder to 20 refill naturally.

With reference to figuec 3, another arrangement of urinary drainage system 30 includes a catheter control unit 31 that has a microprocessor based controller 32 that includes a programming interface 33 for the input of various control 25 parameters 34. In this arrangement, one or more of the fill time, the drainage time and the predetermined pressure level may be modified by re-programming in order to suit a particular patient.

Preferably, the controller 32 may be adaptive so that the predetermined fill time interval may be modified over a period of time according to pressure readings.

For example, frequent incidence of reaching the predetermined pressure level for initiating drainage may suggest that the current predetermined time period 5 is too short. Similarly, a complete absence of any occurrence of the predetermined pressure level may indicate that this pressure level is set too high, or even that the predetermined time period is too short resulting in unnecessarily frequent voiding of the bladder.

10 The microprocessor controller 32 may be programmed to enable the control unit 31 to adapt the fill time interval and / or the predetermined pressure level within allowable limits according to data gathered over a number of fill and drainage cycles.

15 Preferably, the catheter control units of all of the described embodiments include a manual override switch 35 to enable the patient or clinician to override the controller 16 or 32 to open the valve 15 regardless of sensed pressure or elapsed fill time.

20 With reference to figure 4, a still further arrangement of urinary drainage system 40 includes a catheter control unit 41 similar to the arrangement of figure 3 with the addition of a pH sensor 44 for collecting pH data on urine passing through the flow conduit 14 and a flow meter 45 for determining flow rate. The flow meter 45 may deduce flow rate from transient pressure 25 extrapolations, or may comprise a flow meter housed within the flow conduit 14. The flow meter 45 may be used to gather clinical data useful to the clinician, and may also be used to predict blockages in the drainage system.

Such predictions may be useful in indicating a need to change the catheter 2, or possibly provide the clinician with important diagnosis data.

The pH sensor 44 may be used to gather clinical data useful to the clinician or for providing an immediate alarm to the patient or clinician, for example via an audio and/or visual output 43.

The control unit 42 also includes an output interface for transmitting data to an external device. This may be combined with the programming input interface 33 as a bi-directional communication interface. In one embodiment, the bi-

directional input / output interface may be an infrared transmitter / receiver.

10 Alternatively, any suitable communications interface could be used, such as plug-in hard wiring, radio, infra-red, mobile telephone link or others known to the person skilled in the art. Standard computer output interfaces may be used such as USB.

15 As shown in the urinary drainage system 50 in figure 5, the functions of the control unit (ea. lO, 22, 31, 41 of the preceding figures) may be distributed.

The valve 15 and various sensors (ea. 21, 44) may be housed in a first housing 52 which communicates with the other components in a second remote housing 53 by way of any suitable communications link 54, which may be wired or 20 wireless. The wireless link may be any suitable type including radio and infrared. The distributed urinary drainage system 50 enables the catheter control unit Sl to be distributed about the patient's body, maintaining the smallest possible 25 housing 52 adjacent to the proximal end (outlet) 5 of the catheter 2. This offers increased comfort to ambulatory patients.

Figure 6 shows a schematic block diagram of the basic functional elements of the catheter control unit in figure 1. The inlet port 11 preferably includes a

catheter connector 61 and the outlet port 12 preferably includes a bag connector 62. The valve 15, situated in the fluid flow conduit 14 is connected to the controller 16 which comprises an output driver which provides drive signals to the valve 15 and the pre-set timer 17 for counting a predetermined fill time.

5 The timer 17 may be a count up or count down timer. The controller 16 may also include an initialization circuit 64 for ensuring that the system correctly enters an operational state upon power up, and a battery level warning circuit 65. 10 The catheter control units described herein are preferably battery powered, particularly for use with ambulatory patients, but may alternatively use remote power sources for non- ambulatory patients.

Figure 7 shows a schematic block diagram of the basic functional elements of 15 the more complex catheter control system of figure 5. Between the inlet port 11 and catheter connector 61 and the outlet port 12 and bag connector 62 is the fluid flow conduit 14 in which is provided the valve 15, pressure sensor 21, pH sensor 44 and a bag connect sensor 71. These items, with the exception of the bag connect sensor, have been described previously. The bag connect sensor 20 71 prevents opening of the valve 15 unless a suitable urine collection receptacle is detected as being connected to the outlet port 12. Various mechanical and / or electromechanical devices for implementing this will be within reach of the person skilled in the art.

25 Each of the sensors 21, 44, 71 and the valve 15 are connected to the microprocessor 73 which implements the various control functions, such as data logging pressure measurements, flow measurements, pH measurements, as well as running fill timer(s) and drainage timer(s), as required.

The microprocessor 73 and its associated memory (not shown) also maintain the necessary settings for: a) a pressure threshold level 74 that will trigger a drainage cycle (overriding the timer), 5 b) timer settings 65 that determine the duration of the fill and drainage cycles, c) a flow threshold level 76 for triggering an alarm condition if flow falls below a certain level, or for determining when to end a drainage cycle, if this is being used for determining the duration of a drainage cycle, for 10 example,

d) a maximum and / or minimum pH level 78 that may trigger an alarm warning, e) a minimum allowable battery level 77.

15 Conditions that dictate an alarm can be output, together with other logged data, via an input / output interface 33 to a communicating device 80 or may simply trigger a direct audio and/or visual alarm unit 43 (ea. figure 5).

A pressure relief valve bypass 72 may be provided between the inlet port 11 20 and the outlet port 12 for allowing urine flow between the inlet port and the outlet port when the valve 15 is closed, in the event of an overpressure condition existing at the inlet port and / or a failure in the valve mechanism.

The use of a timer based bladder fill cycle offers a number of advantages as 25 discussed above. It is also noted that any collection receptacle can remain empty for most of the time, if it is emptied immediately after filling. This reduces risk of spillage and offers greater comfort to the patient. It is also noted that the timer based solution described herein does not rely on the

patient's ability to apply detrusor pressure to operate, and no mental or physical dexterity is required from the patient.

Other embodiments are intentionally within the scope of the appended claims.

s

Claims

1. A catheter control unit for regulating urine flow through a catheter compnsmg: 5 an inlet port, including catheter connection means; an outlet port; a fluid flow conduit extending between the inlet port and the outlet port, the conduit including a valve for controlling fluid flow through the conduit; and a controller, including a timer, the controller adapted to periodically 10 open the valve upon sensing a predetermined opening condition, a least one opening condition being expiry of a predetermined fill time interval.

2. The catheter control unit of claim 1 further including a pressure sensor for sensing urine pressure, another one of said opening conditions comprising 15 the sensing of urine pressure above a predetermined pressure threshold.

3. The catheter control unit of claim 1, the controller further including means for closing the valve after a predetermined drainage time interval.

20

4. The catheter control unit of claim 1 further including a flow sensor for sensing urine flow rate through the conduit.

5. The catheter control unit of claim 4, the controller further including means for closing the valve after the sensed flow rate has fallen below a 25 predetermined flow threshold.

6. The catheter control unit of claim 1 in which the outlet port further includes a connector for connection of a urine collection receptacle.

7. The catheter control unit of claim 6 further including a connection sensor for detecting the connection of a collection receptacle to the outlet port, the controller further including means for inhibiting the opening of the valve if connection of a collection receptacle is not detected.

8. The catheter control unit of claim I further including timer adjustment means for adjusting the predetermined time interval.

9. The catheter control unit of claim 8 in which the timer adjustment means 10 comprises an external interface for manual adjustment.

10. The catheter control unit of claim I further including at least one of a pressure sensor device for sensing urine pressure, a flow rate sensor for sensing flow rate through the conduit, and a pH sensor for sensing urine pH, the 15 catheter control unit further including a data logging device for receiving inputs from any one or more of the sensors and storing and/or transmitting data related thereto.

11. The catheter control unit of claim 10 further including an external 20 interface for outputting data from the data logging device.

12. She catheter control unit of claim 10 or claim 11 in which the data logging device further includes means for storing information on preceding fill and empty cycles initiated by the valve.

13. The catheter control unit of claim I further including a pressure relief valve bypass for allowing urine flow between the inlet port and the outlet port without opening of the valve in the event of an overpressure condition existing at the inlet port.

14. The catheter control unit of any preceding claim further including an manual override switch for facilitating the opening of the valve independently of the controller.

15. The catheter control unit of any preceding claim in which the unit is fully portable, including attachment means for attaching the unit to a patient's body. 10

16. The catheter control unit of any preceding claim further including a urinary drainage catheter coupled to the inlet port.

17. The catheter control unit of any preceding claim further including a collection receptacle coupled to the outlet port.

18. The catheter control unit of claim 16 further including a catheter insertion and / or retention mechanism.

19. A catheter control unit substantially as described herein with reference 20 to the accompanying drawings.