Patent Publication Number: US-2017348138-A1

Title: A System and a Method for Anal and/or Stomal Irrigation

Description:
The present invention relates to a system and a method for anal and/or stomal irrigation comprising a reservoir for an irrigating liquid, a catheter comprising a catheter tip for insertion into the rectum and/or stoma of a user, and an expandable retention element, such as an expandable balloon, for fixation of the catheter tip within the user&#39;s rectum or stoma. The invention provides in particular a valve and tubing system for controlling the supply of the irrigating liquid to the catheter tip as well as the supply and the withdrawal of the irrigating liquid to and from the expandable retention element. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       The accompanying drawings are included to provide a further understanding of embodiments and are incorporated into and a part of this specification. The drawings illustrate embodiments and together with the description serve to explain principles of embodiments. Other embodiments and many of the intended advantages of embodiments will be readily appreciated as they become better understood by reference to the following detailed description. The elements of the drawings are not necessarily to scale relative to each other. Like reference numerals designate corresponding similar parts. 
         FIG. 1  shows an embodiment of a system for anal and/or stomal irrigation; 
         FIG. 2  shows an embodiment of a tubing and valve system of an embodiment of a system for anal and/or stomal irrigation; 
         FIGS. 3-5  show respective embodiments of flow configurations in the tubing and valve system of  FIG. 2 ; 
         FIGS. 5 a  and 5 b    show embodiments of flow configurations in an alternative embodiment; 
         FIGS. 6 and 7  illustrate exemplary curves of temperature of an irrigating liquid in a reservoir during filling or refilling of irrigating liquid into the reservoir; and 
         FIG. 8  illustrates an embodiment of a method for predicting a temperature of an irrigating liquid in a reservoir of a system for anal irrigation; and 
         FIGS. 9A-9E  illustrate displays of a user-operable control interface for controlling operation of the system. 
     
    
    
     DETAILED DESCRIPTION 
     Control of voluntary bowel functions is frequently limited or absent in patients suffering from certain disabilities, such as spinal injuries, multiple sclerosis or bifid spine. Such lack of control of voluntary bowel functions typically results in faecal incontinence or intractable constipation, as patients have significantly reduced ability to sense the presence of faeces in the colon terminal part and the rectum and to sense the evacuation stimulus. Patients having undergone stomal surgery wherein a catheterizable stoma is constructed may suffer from similar difficulties. 
     It is known to accomplish bowel emptying by irrigation (i.e. flushing) of the rectum or stoma, by an irrigating fluid, such as tap water or saline, which is provided through an intermittent catheter with a tip which is configured and sized for insertion into the rectum or stoma, where it remains in a fixed position by an expandable inflation element, such as a balloon. The balloon may be inflatable by air or by water. Once the rectum or stoma has been flushed with the irrigating liquid, the expandable retention element is allowed to collapse to its non-deflated state, allowing the catheter to be withdrawn from the rectum or stoma, and allowing the liquid and faeces to evacuate. The catheter is connected to a reservoir of the irrigating liquid through a tube, and a pump may be provided for displacing the irrigating liquid from the reservoir to the catheter. 
     The development of transanal or transstomal irrigation systems has hitherto focussed on aspects of tubings, catheters and pumps. It is hence an object to improve known systems further, in particular by improving safety and user-convenience in relation to self-irrigation, and more particularly by improving control and operation of the expandable retention element. 
     Embodiments relate to a system for anal and/or stomal irrigation comprising:
         a reservoir for an irrigating liquid;   a catheter comprising a catheter tip for insertion into the rectum and/or stoma of a user and for expelling of the irrigating liquid from the catheter tip, the catheter further comprising an expandable retention element for fixation of the catheter tip within the user&#39;s rectum or stoma;   a tubing system providing a first conduit for the irrigating liquid between the reservoir and the catheter and providing a second conduit for the irrigating liquid between the reservoir and the expandable retention element;   a valve system in the second conduit for controlling the flow of the irrigating liquid between the reservoir and the expandable retention element;   a pump operable to pump the irrigating liquid from the reservoir to the catheter tip, the pump comprising a reversible pump, which is operable in one direction to pump the irrigating liquid into the expandable retention element for inflation thereof, and which is operable in a reverse direction to withdraw the irrigating liquid from the expandable retention element for collapsing thereof;
 
and
   the pump and the valve system being controllable to selectively:   pump the irrigating liquid into the expandable retention element for expansion thereof;   pump the irrigating liquid through the catheter for expelling of the irrigating fluid from the catheter tip and into the user&#39;s rectum or stoma;   withdraw the irrigating liquid from the retention element for purging thereof.       

     Further embodiments relate to a method of operating a system for anal and/or stomal irrigation, said system comprising:
         a reservoir for an irrigating liquid;   a catheter comprising a catheter tip for insertion into the rectum and/or stoma of a user and for expelling of the irrigating liquid from the catheter tip, the catheter further comprising an expandable retention element for fixation of the catheter tip within the user&#39;s rectum or stoma;   a tubing system providing a first conduit for the irrigating liquid between the reservoir and the catheter and providing a second conduit for the irrigating liquid between the reservoir and the expandable retention element;   a valve system in the second conduit for controlling the flow of the irrigating liquid between the reservoir and the expandable retention element;   a pump operable to pump the irrigating liquid from the reservoir to the catheter tip, the pump comprising a reversible pump, which is operable in one direction to pump the irrigating liquid into the expandable retention element for inflation thereof, and which is operable in a reverse direction to withdraw the irrigating liquid from the expandable retention element for collapsing thereof;
 
said method comprising controlling and operating the pump and the valve system to selectively:
   pump the irrigating liquid into the expandable retention element for expansion thereof;   pump the irrigating liquid through the catheter for expelling of the irrigating fluid from the catheter tip and into the user&#39;s rectum or stoma;
 
withdraw the irrigating liquid from the retention element for purging thereof.
       

     The pump may be manually or electrically driven. The ability of the pump and the valve system to withdraw the irrigating liquid from the retention element for purging thereof allows the retention element to be purged in a controlled manner. Expansion of the retention element as well as collapsing thereof may hence be accurately controlled by adequate control of the pump and the valve system. Collapsing of the retention element by a controlled action, notably by forced purging caused by a pumping action of the pump, enables purging of the retention element even under circumstances, at which the retention element is expanded by a relatively low pressure, which is too low for the irrigating liquid to escape from the retention element merely be opening a valve of the valve system. 
     The pump is preferably an electrically driven pump, and the pump and the valve system are preferably controllable by an electronic control system. 
     The valve system and the tubing system may be configurable to withdraw the irrigating liquid from the retention element during purging thereof by conveying the irrigating liquid from the retention element directly into user&#39;s rectum or stoma without the irrigating liquid passing into or through the reservoir. This incurs several benefits. Firstly, the user is released from encountering the possibly disturbing or uncomfortable experience of noting that irrigating liquid passes from the retention element, which is fixed in the user&#39;s rectum or stoma, back to the reservoir. Accordingly, user comfort and trust in the system is improved. Secondly, as a temperature equilibrium will be achieved between the irrigating liquid within the expanded retention element and the user&#39;s body while the retention element is fixed within the bowel, the irrigating liquid used for expansion may conveniently be used for irrigation (i.e. flushing of the bowel) without the need for any further temperature management for that part of the irrigating liquid. Thirdly, the distance to be travelled by the irrigating liquid and hence power consumption of the pump may be minimized when the irrigating liquid is allowed to pass directly from the retention element to the catheter tip for irrigation of the bowel. 
     Alternatively, however, the pump, the valve system and the tubing system may be configurable to withdraw the irrigating liquid from the retention element during purging thereof by conveying the irrigating liquid from the retention element into the reservoir. 
     In one embodiment, the pump comprises an electrical pump, which is reversible and thereby operable in one direction to pump the irrigating liquid into the expandable retention element for inflation thereof, and which is operable in a reverse direction to withdraw the irrigating liquid from the expandable retention element for collapsing thereof. The ability of the pump to pump irrigating liquid into the retention element and to withdraw the irrigating liquid therefrom may thus be accomplished in an inexpensive manner by a pump, which is easy to operate and control. 
     The valve system within the tubing system is preferably configured to selectively cause one flow configuration selected from a first, second and third flow configuration at a time, wherein:
         the first flow configuration is arranged to cause a transfer of the irrigating liquid, by means of said pump, from the reservoir into the expandable retention element;   the second flow configuration is arranged to transfer the irrigating liquid, by means of said pump, from the reservoir to the catheter;   the third flow configuration is arranged to transfer the irrigating liquid, by means of said pump, away from the expandable retention element.       

     Thus, in the first flow configuration the irrigating liquid is transferred from the reservoir to the expandable retention element for expansion thereof. In the second flow configuration, the irrigating liquid is transferred from the reservoir to the catheter, i.e. to the catheter tip for insertion into the user&#39;s rectum or stoma. In the third flow configuration, the irrigating liquid is transferred away from the expandable retention element, either directly to the catheter tip for flushing of the user&#39;s bowel without the irrigating liquid passing into or through the reservoir, or back to the reservoir. 
     As a safety measure, to prevent rupture of the expandable retention element due to overpressure and/or to prevent the exertion of overpressure to the user&#39;s bowel, a first relief valve may be provided, the valve being configured to open if pressure in a bowel of the user exceeds a first threshold limit in the first flow configuration, i.e. during expansion of the expandable retention element. Preferably, when the first relief valve opens, an amount of the irrigating liquid is transferred to the reservoir or expelled into a toilet facility if the valve, for instance, is placed in a connect portion of the catheter. 
     A second relief valve may be provided as a further or alternative safety measure, the second relief valve being configured to open if pressure in a bowel of the user exceeds a second threshold limit in the second flow configuration, i.e. during flushing of the user&#39;s bowel, so as to transfer an amount of the irrigating liquid to the reservoir or expel it into a toilet rather than keeping pumping irrigating liquid into the user&#39;s rectum or stoma. 
     In general, it may be desirable to transfer liquid to be expelled due to overpressure out of the system, i.e. into a toilet facility, rather than into the system itself, such as into the reservoir. 
     Generally, the valve and tubing system may be operable to redirect the irrigating liquid to the reservoir if the pressure within the expandable retention element exceeds a predetermined threshold level. 
     In order to further control the supply of the irrigating liquid to the expandable retention element and/or to the catheter, the system may comprise:
         a first actively controllable valve arranged in the tubing and/or the catheter at a position between the pump and the expandable retention element; and/or   a second actively controllable valve arranged in the tubing at a position between the pump and the catheter.       

     The actively controllable valves are operable in order to achieve the desired one of the first, second and third flow configuration. More specifically, when the first actively controllable valve is open and the second one is closed, irrigating liquid may pass to the expandable retention from the reservoir, or away from the expandable retention element. In the state wherein the first valve is open and the second one is closed, the direction of flow through the pump may be controllable by the direction of rotation of the pump motor. The destination of irrigating liquid forced away from the expandable retention element may be selected by one or more passively controllable valves, such as check valves, or by one or more actively controllable valves. When the first actively controllable valve is closed and the second one is open, irrigating liquid may pass from the reservoir to the catheter without entering the expandable retention element. 
     At least one check valve is preferably provided for preventing a backflow of the irrigating liquid from the pump in a direction towards the reservoir, so as to force liquid withdrawn from the expandable retention element towards the catheter and into the user&#39;s rectum or stoma. 
     A user-operable control interface may be provided for controlling operation of the valve system and/or the pump. The user may for example select valve settings to select a flow configuration among the above-mentioned first, second and third flow configurations, and the user may further set operating parameters of the system, such as expansion pressure of the retention element, or an operating speed of the pump, i.e. flow rate of irrigating liquid for irrigation, or an irrigation duration. 
     In one embodiment, the pump is operable to repeatedly expand and collapse so as to stimulate the peristaltic of the user&#39;s bowel. Such action of the pump may be activatable by the user through the control interface. Its settings, such as duration or frequency of repeated expansion and collapsing may be defined through the interface. The expandable retention element may be incrementally expandable or collapsible, allowing the user to control expansion or collapsing of the retention element in response to the user&#39;s sensation of the state of expansion. 
     The control system may be configured to control a flow condition of the irrigating liquid at the catheter tip during anal or stoma irrigation. The control system may hence comprise a controller for controlling operation of the pump, at least one sensor for determining a measure of pressure at at least one first predetermined position in the tubing system and/or the catheter during operation of the pump, and a processor for determining or estimating said flow condition at the catheter tip on the basis of said measure of pressure. Further, the control system may be configured to control the pumping operation of the pump in response to said measure of pressure. 
     The provision of the at least one sensor for determining a measure of pressure at at least one first predetermined position in the tubing system and/or the catheter during operation of the pump allows the processor to determine or estimate a flow condition at the catheter tip on the basis of such measure. For example, the rise of the pressure at a particular flow restrictor within the tubing system to a predetermined level may indicate the presence of irrigating liquid at the tip of the catheter. Similarly, the rise of pressure at the catheter tip itself may indicate the presence of irrigating liquid at the tip. 
     In one embodiment, the control system may comprise a memory for storing at least one pressure threshold value indicative of the presence of the irrigating liquid at at least the first predetermined position in the tubing system and/or the catheter and/or at at least one second predetermined position in the tubing system and/or the catheter. In such an embodiment, the control system may be configured to continue the pumping operation of the pump for a limited period of time after determination, by the at least one sensor, of a pressure value at the at least one first predetermined position which is at least equal to the pressure threshold value or a value derived therefrom. For example, one of the first and second predetermined positions may be a position at the catheter tip or in the vicinity thereof, in which case the control system may be configured to continue said pumping operation for a certain duration after the determination of said pressure threshold value. Accordingly, the amount of irrigating liquid expelled from the catheter tip may be accurately controlled by control of said duration. 
     A thermo sensor may further be provided, which is connected to the reservoir for obtaining a measure of a temperature within the reservoir, the tubing system and/or the catheter. The control system may be operatively connected with the thermo sensor, and the control system may be configured to determine a temperature within the reservoir before the irrigating liquid is filled or re-filled into the reservoir, determine an initial change of the temperature within the reservoir upon commencement of filling or refilling of the irrigating liquid into the reservoir, and predict a future asymptotic value of the temperature within the reservoir on the basis of at least the initial change. The control system may further be configured to continuously determine a current temperature or a current rate of change of the temperature within the reservoir while the irrigating liquid is filled or refilled into the reservoir, and to continuously update the prediction of the future asymptotic value of the temperature within the reservoir on the basis of at least said current temperature and/or rate of change of the temperature. 
     Thanks to the thermo sensor and the control system, a prediction of the future asymptotic value of the temperature within the reservoir once filled, notably of the irrigating liquid, may be made. As the prediction of the future asymptotic temperature value is continuously updated on the basis of the current temperature and/or the rate of change of temperature, a change of temperature of the liquid supplied to the reservoir, such as for example a change of the ratio between hot and cold tap water, is adequately reflected in the temperature prediction. The temperature prediction may be communicated to the user, e.g. via a display of the system, thus allowing the user to ascertain if the temperature of the supplied liquid, typically tap water, is to be increased or decreased. 
     DETAILED DESCRIPTION OF THE DRAWING 
     Embodiments, and features of the various exemplary embodiments described in this application, may be combined with each other (“mixed and matched”), unless specifically noted otherwise. 
       FIG. 1  shows an embodiment of a system for anal and/or stomal irrigation. The system comprises a catheter  100  sized and configured for insertion into the rectum or stoma of a user. A housing for a pump  101  is provided for transferring an irrigating liquid contained within a reservoir  102  to the catheter  100  and to an expandable retention element  104  in the form of a balloon configured to fixate the catheter within the user&#39;s rectum or stoma. A control system  103  for the pump and a valve system (not visible in  FIG. 1 ) is further housed within the housing of the pump  101 . Tube portion  119  connects the reservoir  102  to the pump  101 , and tube portion  121  connects the pump within the housing of the pump  101  to the catheter  100  and expandable retention element  104 . As discussed in further detail in relation to  FIGS. 2-5  below, tube portion  121  includes separate conduits for connecting the pump to the catheter for expelling of irrigating liquid from the catheter tip and for expansion of the balloon  104 , respectively. Tube portion  119  attaches to dip tube  129  for sucking irrigating liquid from the reservoir  102 . The housing of the pump  101  is provided with a display  123  for communicating an operating state of the system and/or an asymptotic temperature value to the user, and user-operable control buttons  125  are provided as part of a user operable control interface for controlling operation of the valve system (not visible in  FIG. 1 ) and/or pump  101 . A thermo sensor  128  attaches to a wall of the reservoir  102 , a wired connection  127  being provided for communicating a signal from the thermo sensor  128  to the control system  103  within housing of the pump  101 . 
       FIG. 2  illustrates an embodiment of a tubing and valve system of the system of  FIG. 1 . As shown, pump  101  is connected to reservoir  102  via conduit  120  comprising a first check valve  124 . The conduit  120  is provided within tube portion  119  (see  FIG. 1 ). The first check valve  114  may be provided within tube portion  119 , or within the housing of the pump  101 , or within the dip tube  129 . Downstream of the pump (when seen in flow direction from the reservoir towards the catheter  100  and the balloon  104 ), the tubing system has two branches, one of which includes conduit  122  connecting to the balloon  104  via a first actively controllable valve  106 . The conduit  122  is provided within tube portion  121 . The first actively operable valve  106  may be provided within the tube portion  121 , or within the catheter  100 , or within the housing of the pump  101 . The other branch of the tubing system downstream of the pump includes conduit  124  connecting to the catheter  100  via a second actively controllable valve  108 . The conduit  124  is provided within tube portion  121 . The second actively operable valve  108  may be provided within the tube portion  121 , or within the catheter  100 , or within the housing of the pump  101 . As shown by dashed lines in  FIGS. 2-5 , the actively controllable valves  106  and  108  are controllable by the control system  103 . 
     A pressure sensor  105  is provided for measuring pressure at at least one first predetermined position in the tubing system  119 ,  120 ,  121 ,  122 ,  124  and/or the catheter  100  during operation of the pump  101 . The pressure sensor  105  outputs a signal to the control system  103 , which operates the pump and/or the actively controllable valves  106 ,  108  on the basis of said signal and other signals as described herein. The control system  103  includes a processor for determining or estimating a flow condition at the catheter tip on the basis of the measure of pressure provided by pressure sensor  105 , and the control system is configured to control the pumping operation of the pump in response to said measure of pressure. More specifically, the control system continues pumping operation of the pump  101  for a limited period of time after determination, by the pressure sensor  105 , of a pressure value which is at least equal to a pressure threshold value or a value derived therefrom. Thus, the amount of irrigating liquid expelled from the catheter tip may be accurately controlled. In the embodiment shown, the pressure sensor  105  is arranged in the tubing system  121 ,  124  in the vicinity of the catheter  100  or within the catheter  100  itself. 
     Control system  103  further receives input from user-operable control buttons  125 , and thermo sensor  128 , and control system  103  communicates data to display  123 . The data communicated to display  123  may include a predicted future asymptotic value of the temperature of the irrigating liquid within the reservoir  102  as determined by thermo sensor  128 . The data may be continuously updated as the control system  103  continuously updates the temperature prediction while irrigating liquid is being filled or re-filled into the reservoir. 
     First and second relief valves  110  and  112  are provided for allowing irrigating liquid to escape from the balloon  104  or from the catheter  100  in case the pressure therein exceeds the threshold pressure defined by the relief valves. The first relief valve  110  drains liquid from the balloon  104  to the reservoir  102  in the case of excessive pressure within the balloon  104 , and the second relief valve drains liquid from the catheter  100  to the reservoir  102  in the case of excessive pressure within the user&#39;s rectum or stoma. 
     Further, first and second check valves  114  and  116  are provided for preventing undesired backflow of liquid in the tubing system. The first check valve  114  is provided within conduit  120  between the pump  101  and the reservoir  102  in order to prevent backflow of irrigating liquid from the pump  101 , or any position downstream of the pump, to the reservoir  102 . The second check valve  116  is provided in a side branch in the tubing system connecting conduit  124  to conduit  120 . The first and second check valves  114  and  116  may be provided within tube portions  119  and  121  (see  FIG. 1 ) or within the housing of the pump  101 , or alternatively the first check valve  114  may be provided in dip tube  129 . Second check valve  116  may be provided within the catheter  100 . 
       FIGS. 3-5  show respective embodiments of flow configurations in the tubing and valve system of  FIG. 2 . In the first flow configuration  201  shown in  FIG. 3 , the first actively controllable valve  106  is open, and the second actively controllable valve  108  is closed while the pump  101  operates. Accordingly, irrigating liquid is transferred from the reservoir  102  to the balloon  104  for expansion thereof. In the second flow configuration  202  shown in  FIG. 4 , the second actively controllable valve  108  is open, and the first actively controllable valve  106  is closed while the pump  101  operates. Irrigating liquid is thus transferred from the reservoir  102  to the catheter  100 , at the tip of which the liquid is expelled into the user&#39;s rectum or stoma so as to irrigate the user&#39;s bowel. In the third flow configuration  203  shown in  FIG. 5 , operation of the pump  101  is reversed, and the first actively controllable valve  106  is open, while the second actively controllable valve  108  is closed. The balloon  104  is hence purged, and the irrigating liquid withdrawn therefrom flows from the balloon  104  to the catheter  100 , at the tip of which it is expelled. 
     In the alternative embodiment of  FIGS. 5 a  and 5 b   , in which the balloon  104  may be emptied into the reservoir  102  by forced action of the pump  101 . The dashed lines in  FIGS. 5 a  and 5 b    indicate respective flow configurations for expanding the balloon and purging thereof into the reservoir.  FIG. 5 b    indicates a flow configuration for expelling of the irrigating liquid through the catheter. In the flow configurations of  FIG. 5 a   , a first actively controlled valve AV 1  is open, and a second actively controlled valve AV 2  is closed. For expansion of the balloon, the pump  101  operates in a first operating direction, whereas for purging, i.e. collapsing of the balloon, the pump  101  operates in a second operating direction opposite to the first operating direction. In the flow configuration of  FIG. 5 b   , the first actively controlled valve AV 1  is closed, and the second actively controlled valve AV 2  is open. Check-valve CV 1  prevents backflow of the irrigating liquid from the catheter tubing conduit towards the reservoir. 
       FIGS. 6 and 7  illustrates exemplary curves of temperature of the irrigating liquid in the reservoir  102  during filling or refilling of irrigating liquid into the reservoir. In the chart of  FIG. 6 , the initial temperature of the irrigating liquid within the reservoir  102  as determined by thermo sensor  128  is approximately 20° C. As the user&#39;s bowel should be irrigated with liquid at a temperature not exceeding approximately 40° C., preferably at a temperature of 20-40° C., most preferably at a temperature of 36-38° C., the user starts pouring liquid, such as tap water, at an elevated temperature into the reservoir. 
     Next, an initial change of the temperature within the reservoir is determined by the thermo sensor  128  upon commencement of filling or refilling of the irrigating liquid into the reservoir  120 . In  FIG. 6 , the initial temperature change is represented by elevated temperature TINT at time t 1 . On the basis of the initial temperature change, a future asymptotic value of the temperature, denoted “True” in  FIG. 6 , within the reservoir is predicted on the basis of at least the initial change. 
     As shown in  FIG. 7 , a current temperature or a current rate of change of the temperature within the reservoir is continuously determined by means of thermo sensor  128  and control system  103 , while the irrigating liquid is filled or refilled into the reservoir, and the prediction of the future asymptotic value of the temperature within the reservoir is continuously updated on the basis of at least said current temperature and/or rate of change of the temperature. More specifically, at the start of the filling or refilling procedure, an initial temperature change T 1  is determined at a first point in time, t 1 . The first initial temperature change as represented by T 1  is used for a first prediction, TA, of a future asymptotic temperature value of the irrigating liquid within the reservoir  102  once filled. At a second point in time, t 2 , when the temperature as determined by the thermo sensor  128  has reached level T 2 , the temperature of the liquid supplied to the reservoir changes, for example as the user changes the ratio of hot to cold water in the tap. At a third point in time t 3 , a third temperature value T 3  is obtained, and second prediction TB is made. Subsequently, at a fourth point in time, t 4 , a fourth temperature level T 4  is reached, and the temperature of the liquid filled into the reservoir  102  changes abruptly for a second time. The change of the supplied liquid is reflected by temperature T 5  at time t 5 , on the basis of which a third asymptotic temperature prediction T∞ is made. 
     During the above procedure, the predicted temperature values TA, TB and T∞ are shown to the user via display  123  (see  FIGS. 1-5 ) as they are determined by the control system  103 . 
     The above procedure of continuously determining and updating the asymptotic temperature prediction is generally depicted in  FIG. 8 . 
       FIGS. 9A-9E  illustrate displays of a user-operable control interface for controlling operation of the system. In  FIGS. 9A and 9B , the display provides instructions for the user to hold on to the catheter. As the user activates the “Empty” button, emptying of the balloon (retention element) commences.  FIG. 9C  illustrates a display shown to the user while emptying is in progress. A pause button is provided allowing the user to pause emptying. A paused emptying state of the system results in the display setting shown in  FIG. 9D . Upon completion of emptying, the user is instructed via the display to remove and dispose of the catheter, cf.  FIG. 9E .