GB2506353A - Pressure sensor to assist in the management of a surgical stoma - Google Patents

Abstract

A surgical stoma management device including a pressure detector 3 arranged to detect excess pressure in a stoma waste container 2 and an alert means activatable by said excess pressure. The alert which is generated by the device will be beneficial in the detection of conditions which might be a precursor to leakage of waste product from an arrangement of stoma waste containers. The alert may be audible or visible and may be remote from the sensor. The pressure detector may mount onto a conduit forming the waste collection system, may or may not be in fluid communication with the waste, or may connect to an outlet port of a waste container.

Description

Device to assist in the management of a surgical stoma The present invention relates to ostomy appliances.

Persons who have had ostomy surgery known as ostomates have to take great care in the management of the various appliances used to collect and store the waste products from their stoma. A stoma is a surgically formed outlet from the ileum, colon or urinary duct; which outlet is formed in the wall of the abdomen. The main types of such ostomy surgery are ileostomy, colostomy (both for the expulsion of intestinal waste) and urostomy (for the expulsion of urine). The various surgical appliances used for the collection and storage of such waste include adhesive components, bags, pouches, pipework and pipework connectors. In some instances a collection bag or pouch is located a short distance from the stoma and the waste products are conveyed to it by means of pipework; and in other instances a collection bag or pouch is located in the immediate vicinity of the stoma without the use of any pipework. The term waste container is used hereinafter to describe any part of a system for the collection and storage of waste from a surgical stoma which contains or may contain waste from the stoma. Such waste containers may include but is not limited to pouches, bags, pipes, ducts and pipework connectors.

Special attention from the ostomate is generally given to ensuring that the integrity of this arrangement of waste containers is maintained and that it remains completely leak-free. The occurrence of any unintentional leakage is potentially extremely distressing and inconvenient for the ostomate.

Indeed leakage may cause serious social implications for the ostomate and have a major negative impact upon quality of life. In addition to the effect upon the ostomate, others may also suffer the effects of a leakage because for example of the resulting odour and the soiling of clothing, furnishings, flooring and other items.

Provided that the various surgical appliances are used correctly then the likelihood of leakage is reduced. However even with correct usage, leakage is still likely in the event of excess pressure being present within a waste container. Such excess pressure may cause leakage at any of several points in an arrangement of waste containers, notably at the adhesive bond between the skin of the ostomate and the adjacent waste container, and at connection points between waste containers (which are commonly of the manual push-fit variety). Excess pressure within any waste container presents the risk of a complete failure at these various points which is likely to result in a catastrophic leakage whereby a relatively large volume of waste product is released. Clearly such a catastrophic failure is likely to have a significantly worse impact than a minor leak.

There are several cornnion mechanisms whereby excess pressure within waste containers is likely to occur. Firstly there is the eventuality where the total volume of the waste containers has become full to capacity and the stoma continues to expel waste product. Secondly is when the total volume of the waste containers is partially or completely full and a waste container is squashed or squeezed. Squashing or squeezing of a waste container may occur for example if a person or object were to press against the ostomate in a crowded environment or if the ostomate were to press against a waste container whilst sleeping.

It should be realised that the effective total capacity of the waste containers may be significantly reduced in the event that a blockage has occurred. Such blockages may occur for example by the crushing of pipework forming a waste container which is likely to happen if the ostomate sits on a pipe when seated in a chair, or lies upon a pipe when in bed.

Blockages may also occur because of the transit through a waste container of stones which are broadly similar in nature to kidney stones and which may be expelled from a stoma. Such stones may be unable to pass through a waste container such as a pipe which has a cross-section which is small in comparison to the size of a stone, and are hence likely to cause blockages. Clearly in the event of a blockage it is more difficult to effectively manage the use of the various appliances because the capacity has been unexpectedly reduced and hence it is not easy for the ostomate to plan for scheduled controlled emptying of the waste containers.

It should further be realised that the effective total capacity of the waste dontainers may be significantly reduced in the event of a physical restriction being present which limits the possible volumetric expansion of flexible waste containers such as waste storage pouches or bags. Such waste containers are commonly located within the clothing of the ostomate, and the tightness of the clothing may restrict their volumetric expansion. Again this may present difficulties in the effective management of the various appliances.

A still further set of difficulties may arise in the effective management of ostomy devices in that the ostomate may be temporarily or permanently incapacitated and therefore unable to carry out the timely emptying of waste containers and other associated tasks. Such incapacity may arise for example simply because the ostomate is asleep, or if the ostornate is mentally or physically impaired.

A surgical stoma management device according to the present invention includes a waste container and a pressure detector arranged to detect excess pressure in the waste container and an alert means activatable by said excess pressure. The alert means may be immediately adjacent to the ostornate in order to alert him or her directly or it may be remote from the ostomate so as to alert another person.

Because of the likelihood of an excess pressure condition being the cause of leakage, it is beneficial for a warning to be given that excess pressure has occurred within a waste container. Such a warning would allow the cause of the excess pressure to be investigated and remedied before leakage occurs. The alert means may be vibratpry or may produce an audible or visual indication. The device may be powered at least in part by electrical or mechanical means. The detector may comprise at least apressure detecting element in or separate from fluid communication with an inlet port of the device. The inlet port may be removeably fitted to a bag forming part of the waste container. An outlet port if present may be provided with a sealing cap. The detector may be mounted in a conduit between waste containers. The detector may be in fluid communication with the waste container either by means of a flexible conduit connected to the waste containerat a separate location to an emptying port or directly to the emptying port.

The invention will now be described with reference to the accompanying drawings in which: Figure 1 shows an ostomate having an ostomy bag provided with a pressure detecting means and an alert means according to a first embodinient of the invention, Figure 2 shows a simplified diagram in partial cross-section of the first embodiment shown in Figure 1 showing the key functional components, Figure 3 is a functional block diagram of the first embodiment shown in Figure 1 Figure 4 shows an ostomate having an ostomy bag with a pressure detecting means and a separate alert means according to a second embodiment of the invention; the ostomate being equipped with a waste container which stores the waste products in a bag located some short distance away from the stoma, Figure 5 is a simplified diagram in partial cross-section of the first part of the second embodiment shown in Figure 4 showing the key functional components, Figure 6 is a simplified diagram in partial cross-section of the second part of the second embodiment shown in Figure 4 showing the key functional components, Figure 7 is a functional block diagram of the first part of the second embodiment shown in Figure 4, Figure 8 is a functional block diagram of the second part of the second embodiment shown in H Figure 4, Figure 9 is a simplified diagram in partial cross-section of an alternative device for pressure detection to that shown in Figure 5 using a force-measuring device which is isolated from the waste products by way of the wall of a pipe within which waste products are contained according to a third embodiment of the invention, Figure 10 shows an alternative arrangement of pressure detection similar to that shown in Figure 9 except that the device is mounted to an ostomy bag of modified form according to a fourth embodiment of the invention, Figure 11 is a simplified diagram in partial cross-section the fourth embodiment shown in Figure 10 showing the key functional components, Figure 12 shows an alternative arrangement of pressure detection whereby a pipe is used as a pressure transmitting device, one end of which is located within a waste container and the other end of which is located at the pressure detecting device according to a fifth embodiment of the invention, Figure 13 shows a further arrangement of pressure detection similar to that shown in Figure 12 except that the pressure detecting device is equipped with only a single pipe connection port according to a sixth embodiment of the invention, Figure 14 is a simplified diagram in partial cross-section of the sixth embodiment shown in Figure 13 showing the key functional components, Figure 15 shows an alternative usage of the sixth embodiment of the invention shown in Figures 13 and 14 wherein the ostomate is equipped with a waste container which stores the waste products in a bag located some short distance away from the stoma and Figure 16 shows an alternative form whereby the pressure detector is integral to an ostomy bag and the alert means is remote from the ostomy bag according to a seventh embodiment of the invention.

Figure 1 shows a general view of an ostomate 1 equipped with a waste collection bag 2 located immediately adjacent to the stoma of the ostomate who is located behind bag 2. A pressure detecting and alert device 3 is connected directly to an emptying port of the bag 2 such that the device 3 is located in intimate contact with the ostomate 1. In the absence of the device 3 this emptying port is generally used for emptying the bag 2 of the collected waste. The device 3 permits the through passage of waste for the purpose of emptying the bag 2 in a controllable manner. This passage may be blocked in order to contain the waste by way of a cap 4 fitted to the device 3. In this example the waste container includes the bag 2.

Figure 2 shows in detail the mechanical details of the first embodiment. An inlet port 6 is connected to the emptying port 5 of the ostomy bag 2 by way of a liquid-tight manual interference fit. The inlet port 6 is connected to an outlet port 7 by way of a first gallery 8. The cap 4 is fitted to the outlet port 7 by way of a liquid-tight manual interference fit in order to prevent escape of waste from the bag 2. The bag 2 may be emptied by removal of the cap.

Aside from the inlet port 6 and outlet port 7 the pressure detection means of the invention is contained within an enclosure 9. Ideally the enclosure 9 will be substantially sealed against the ingress of liquid in order to protect the various internal components in the event that it is exposed to contamination which includes waste product from the stoma. Such liquid ingress-protection will also permit the convenient washing of the device 3 by way of irrigation using water or other cleaning compounds.

Within device 3 a pressure switch 10 is connected to the first gallery S by way of a second gallery 11. The pressure of the fluid in the first gallery 8 and second gallery 11 acts upon the first face of a diaphragm 12 forming part of the pressure switch 10. The second face of the diaphragm 12 is subjected to atmospheric pressure such that the diaphragm will move according to the pressure differential between the second gallery 11 and atmospheric pressure. Switch contacts 13 are mechanically coupled to the diaphragm 12 and form a further part of the pressure switch 10. The switch contacts 13 will remain in an open-circuit condition provided that the differential pressure across the diaphragm 12 is low. When this differential pressure exceeds a preset threshold in the sense that the pressure in the second gallery 11 exceeds atmospheric pressure by more than a preset value then the switch contacts 13 will assume a short-circuit condition. This action is reversible and repeatable whereby the switch contacts 13 will become open-circuit when the differential pressure drops below the preset threshold and will become short-circuit again when the pressure differential rises above the preset threshold. It will therefore be seen that a short-circuit condition of the switch contacts 13 is ndicative of an excess pressure condition within the waste container.

The switch contacts 13 of the pressure switch 10 are connected to an electronic module 14 incorporating electronic components as required in order to provide the control functions necessary for the implementation of the invention. Power for the operation of the invention is provided by an electrical battery 15 which is connected to the electronic module 14. A vibrating device comprising of-an-electric motor 16 and mass 17 is also connected to the electronic module 14. The mass 17 is eccentrically attached to the rotation-conveying output shaft of the electric motor 16 such that operation of the motor generates an oscillating force due to the rotational movement of the eccentric mass. Because of the intimate contact between the device 3 and the ostomate 1 the oscillating force will be perceived by the ostomate as a vibration acting as an alert.

The function of the electronic module 14 is such that in the event of a short-circuit condition.

of the switch contacts 13 power is applied to the electric motor 16 which in turn generates an oscillating force. It will therefore be seen that in the event of an excess pressure condition within the waste container the ostomate 1 will be alerted by way of the vibration of the device 3.

Figure 3 shows a functional block diagram of the first embodiment with the pressure switch 10 the electronic module 14 the battery 15 and the electric motor 16.

Figure 4 shows a general view of an ostomate 1 equipped with a waste collection pouch 18 located immediately adjacent to the stoma of the ostomate. An inlet port 46 of the first part of a second device 19 is connected directly to the outlet port 45 of the collection pouch 18. The outlet port 47 of the second device 19 is connected to the first end of a flexible pipe 20. The second end of the flexible pipe 20 is connected to a waste storage bag 21. It will be seen that the waste from the stoma will pass through the device 19 and the flexible pipe 20 and will be stored in the waste storage bag 21. The waste storage bag 21 is equipped with an emptying port 22 which may be closed by way of a plug or cap in order to prevent escape of waste.

The bag 21 may be emptied by removal of the plug or cap. Associated with device 19 is a receiver unit 23 of the second embodiment which is physically disconnected from the device 19 and is carried by the ostomate 1 in a convenient location such as in a pocket in clothing being worn. In this example the waste containers include the waste collection pouch 18, the flexible pipe 20 and the waste storage bag 21.

Figure 5 shows in detail the mechanical details of device 19. This is physically and functionally similar in most respects to device 3 shown in Figure 2. It incorporates an inlet port 46, an outlet port 47, a first gallery 48, a second gallery 51, a pressure switch 50 incorporating a diaphragm 52 and switch contacts 53, an electronic module 54, an electrical battery 55 and an enclosure 49.

Connected to the electronic module 54 is a radio transmission antenna 24. The function of the electronic module 54 is such that in the event of a short-circuit condition of the switch contacts 53, a radio signal is transmitted from the transmission antenna 24.

Figure 6 shows in detail the mechanical details of receiver unit 23 A radio reception antenna is connected to an electronic module 26 incorporating electronic components as required in order to provide the control functions necessary for receiver unit 23. Power for the operation of the receiver unit 23 is provided by an electrical battery 27 which is connected to the electronic module 26. Also connected to the electronic module 26 is an audible sound generator 30, a visual indicator lamp 31 and a vibrator mechanism comprising an electric motor 28 coupled to an eccentric mass 29. The entirety of the second part of the embodiment is contained within an enclosure 32.

The function of the electronic module 26 is such that in the event of the reception of a radio signal by the reception antenna 25 which is transmitted from the device 19 power is applied to the electric motor 28 which in turn generates an oscillating force. In this condition the electronic module 26 will also cause the sound generator 30 to produce an audible signal and also cause the indicator lamp 31 to generate a visual alert. It will therefore be seen that in the event of an excess pressure, condition within the waste containers the ostomate 1 will be alerted by way of the vibration of the receiver unit 23 together with an audible alert and a visual alert.

Optionally the receiver unit 23 may incorporate the means for the user to selectively and individually enable or disable the vibrator motor 28, the sound generator 30 and the indicator lamp 31 so that the preferred alert means may be selected.

Figure 7 shows a functional block diagram of device 19 with the pressure switch 50, the electronic module 54, the battery 55, and the radio transmission antenna 24.

Figure 8 shows a functional block diagram of receiver unit 23 with the radio reception antenna 25, the electronic module 26, the battery 27, the sound generator 30, the indicator lamp 31 and the electric motor 28.

Optionally the invention may make use of part of the arrangement of waste containers for the purpose of indirect pressure measurement. With reference to the device 19 illustrated in Figure 4 and Figure 5 such a part used for the purpose of indirect pressure measurement may include but is not limited to the waste collection pouch 18, the flexible pipe 20 or the waste storage bag 21. The use of such a part may be such that a flexible section of the waste-containing wall of the part is used as a force-transmitting component which will permit the pressure within the waste container to be indirectly detected by the invention or part of the invention which is situated externally to the waste container. An example of such an embodiment is shown in Figure 9 which includes only those parts of the invention which relate to the implementation of this optional feature.

Figure 9 shows the flexible pipe 20 which is located within a mechanical housing 33. A plunger component 34 which is constrained to move only in a single linear axis is held against the outer wall of the flexible pipe 20 by way of a force due to a helical wire spring 35 such that the naturally cylindrical shape of the pipe 20 is locally deformed in the region 36.

The maximum deformation of the pipe 20 is such that the flow of waste through the pipe is not significantly impeded. The plunger is coupled to switch contacts 37 which are of a similar type to contacts 53 illustrated in figure 5, and are normally in an open-circuit condition when the flexible pipe 20 is locally deformed as previously described. In the event of an excess pressure condition within the pipe 20 the deformed section of pipe will tend to be (estored to its natural cylindrical form, causing the plunger 34 to move in a direction so as to further compress the spring 35 and causing the switch contacts 37 to assume a short-circuit condition. This arrangement of mechanical housing 33, plunger 34, spring 35 and switch contacts 37 may take the place of the inlet port 46, outlet port 47, first gallery 48, second gallery 51 and pressure switch 50 permitting operation substantially as described as for device 19 or the equivalent of device 3. In this example the waste containers include the waste collection pouch 18, the flexible pipe 20 and the waste storage bag 21.

With reference to the device 3 illustrated in Figure 1 and Figure 2 a further form of the invention which makes use of the arrangement of waste containers for the purpose of indirect pressure measurement is shown in Figure 10.

Figure 10 shows an ostomate 1 equipped with an ostomy bag 80 having a modified form such that the bag has an upper section and a lower section, these being connected together by way of a conduit-like middle section. The upper section of the bag serves to collect waste from the stoma and is bonded to the skin of the ostomate around the periphery of the stoma.

The lower section of the bag 80 is intended for storage of waste from the stoma and is equipped with an emptying port 94 which may be closed by way of a plug or cap to prevent escape of waste. The bag 80 may be emptied by removal of the plug or cap. The conduit between the upper and lower sections of the bag is a hollow narrow section through which waste may pass. The conduit section of the bag serves as a location for the mounting of a device 81 which comprises at east a pressure detecting means and an alert means. In this example the waste container includes the ostomy bag 80.

Figure 11 shows in detail the mechanical details of device 81 shown in Figure 10. As previously described, the ostomy bag 80 has an upper section 82 and a lower section 83 these being connected together by way of a conduit section 84. The device 81 is mounted to the ostorny bag 80 such that the conduit section 84 passes through the device 81, the device circumferentially enclosing at least part of the conduit section. The device 81 is such that it may be removed from the ostomy bag 80 and repeatedly mounted to other similar bags in order to permit its continued use with ostomy bags, which are consumable.

The conduit section 84 is located within a mechanical housing 85. A plunger component 86 which is constrained to move only in a single linear axis is held against the outer wall of the conduit section 84 by way of a force due to a helical wire spring 87 such that the naturally cylindrical shape of the conduit section 84 is locally deformed in the region 88. The maximum deformation of the conduit section 84 is such that the flow of waste through the conduit is not significantly impeded. The plunger is coupled to switch contacts 89 which are of a similar type to contacts 13 illustrated in Figure 2, and are normally in an open-circuit condition when the conduit section 84 is locally deformed as previously described. In the event of an excess pressure condition within the ostomy bag the deformed section of pipe will tend to be restored to its natural cylindrical form, causing the plunger 86 to move in a direction so as to further compress the spring 87 and causing the switch contacts 89 to assume a short-circuit condition. This arrangement of mechanical housing 85, plunger 86, spring 87 and switch contacts 89 may take the place of the inlet port 6, outlet port 7, first gallery 8, second gallery 11 and pressure switch 10 permitting operation substantially as described as for device 3 or the equivalent of device 19.

Optionally the invention may make use of an arrangement for pressure detection whereby the pressure detector is located a small distance from the arrangement of waste containers and where the pressure internal to the waste containers is transmitted to the detector by way of a pipe or other hollow pressure-conveying means. An example of such an embodiment is shown in Figure 12.

Figure 12 shows an ostomate equipped with a waste collection bag 2 located immediately adjacent to the stoma. The waste collection bag is used in a conventional manner whereby the emptying port 5 is sealed with a plug which may be removed in order to empty the bag.

The invention 3 is located a small distance away trom the collection bag 2 and is equipped with a pressure-conveying pipe 38 the first end of which is connected to the inlet port 6 of The invention. The second end 39 of the pipe 38 is located within the collection bag 2 in the immediate vicinity of the stoma such that the internal bore of the pipe is subjected to the same pressure as the contents of the collection bag. The pressure within the collection bag 2 is therefore conveyed to the pressure detecting means within the invention 3 permitting operation of the invention substantially as previously described for the first embodiment of the invention 3 as shown in Figures 1, 2 and 3. The outlet port 7 of the invention is sealed by way of a plug 4 to prevent egress of waste at this point. At the point 40 where the pipe 38 passes through the wall of the collection bag 2 it is essential that the wall of the collection bag is sealed to the outer surface of the pipe in order to prevent egress of waste at this point.

In this example the waste containers includes the waste collection pouch 2.

Optionally the invention may be equipped with only a single port for connection to the waste containers, the said port being able to convey the pressure within the said waste containers to a pressure detecting means within the invention. In such an embodiment the lack of a further connection would preclude the possibility of allowing the flow of waste from the stoma through the invention. A device of this type is shown in Figure 13.

Figure 13 shows a device 61 which is located a small distance away from the collection bag 2 and is equipped with a single port 67 and with a pressure-conveying pipe 38 the first end of which is connected to the inlet port 67 of the device. The second end 39 of the pipe 38 is located within the collection bag 2 in the immediate vicinity of the stoma such that the internal bore of the pipe is subjected to the same pressure as the contents of the collection bag. This embodiment of the invention operates in a similar manner to the fifth example embodiment shown in Figure 12. In this example the waste container includes the waste collection pouch 2.

Figure 14 shows in detail the mechanical details of device 61 as shown in Figure 13. The pressure-conveying pipe 38 is connected to the port 67. The galleries 68 and 71 permit the pressure within the pipe 38 to be communicated to the pressure switch 70 comprising of a diaphragm 72 and switch contacts 73. The device also incorporates an enclosure 69, an electronic module 74, an electrical battery 75 and a vibrating device comprising of an electric motor 76 and eccentric mass 77. The device functions in a similar manner to the first example embodiment as shown in Figures 1, 2 and 3 except that it does not include a plurality of pipe connection ports and thus will not permit the flow of waste from the stoma through the device.

-Figure 15 shows an alternative use of the invention having only a single port for connection to the waste containers as previously shown in Figure 13.

Figure 15 shows a general view alan ostomate 1 equipped with a waste collection pouch 18 located immediately adjacent to the stoma of the ostomate. The outlet port 45 of waste collection pouch 18 is connected to the first end of a flexible pipe 62. The second end of the flexible pipe 62 is connected to a waste storage bag 21. The waste storage bag 21 is equipped with an emptying port 22 which may be closed by way of a plug or cap to prevent escape of waste. The bag 21 may be emptied by removal of the plug or cap. The flexible pipe 62 is equipped with a tee connector 63 to which is connected the first end of a further flexible pipe 64. The waste from the stoma will pass through the tee connector 63 and the flexible pipe 62 and will be stored in the waste storage bag 21. The flexible pipe 64 serves as a pressure-conveying pipe the second end of which is connected to port 67 of the device 61 which is located a small distance away from the collection pouch 18. The pressure within the flexible pipe 62 is therefore conveyed to the pressure detecting means within the invention 61 permitting operation of the invention as previously described for the sixth embodiment of the invention 61 as shown in Figures 13 and 14. In this example the waste containers include the waste collection pouch 18, the flexible pipe 62, the tee connector 63 and the waste storage bag 21.

The various example embodiments previously described consist of physical arrangements of the invention such that they consist substantially of parts and components which are external to and additional to the stoma waste containers. Some components of the invention with such an arrangement may however serve a secondary purpose of containment of waste from the stoma This is true for example of the inlet port 6, the outlet port 7, the first gallery 8 and the second gallery 11 of the first example embodiment aiready described and illustrated in Figures 1, 2 and 3. In this respect the embodiments of the invention previously described may be considered as being additional to a conventional arrangement of waste containers.

Optionally the invention may incorporate components which are integral to the arrangement of waste containers and which serve the purpose of the detection of excess pressure and generation of an alert as described. Such an embodiment is shown in Figure 16.

Figure 16 shows an ostomate 1 equipped with an ostomy waste collection bag 95. Integral to the waste collection bag 95 is a device 96 which is functionally similar to device 19 shown in Figures 4 and 5 but in a physical form to suit this embodiment. Device 96 incorporates a pressure detector, electronic module, battery and radio transmission antenna all of which perform similar functions to the corresponding components of device 19. Associated with / device 96 is a receiver unit 23 which is physically disconnected from the device 96 and is carried by the ostomate 1 in a convenient location such as in a pocket in clothing being worn.

The receiver unit 23 is similar in form and function to that of the second embodiment as illustrated in Figures 4, 6 and 8. The ostomate 1 will therefore be alerted to an excess pressure condition within the waste collection bag 95 by way of an alert generated by the receiver unit 23. In this example the waste containers includes the waste collection pouch 95.

The invention is not limited to the particular embodiments described hereinbefore and in particular may incorporate many possible alternative configurations of the basic elements of the embodiments described. Such elements which may be combined include: the number of ports for the connection of fluid, either permitting or precluding the through flow of waste from the stoma; the inclusion of the pressure detecting means and the alert means within a single unit or the separation of these means into physically separate units; the use of a pressure detecting means which is directly exposed to waste from the stoma or the indirect detection of pressure using part of the arrangement of waste containers as a pressure-transmitting means; the location of the pressure detecting means immediately adjacent to the arrangement of waste containers or its location some distance away and making use of a pressure-transmitting conduit; and the provision of the invention as an addition to the arrangement of waste containers or its partial or complete integration into parts of the said arrangement.

Optionally the invention may incorporate any alert means in order to warn of the presence of an excess pressure condition including but not limited to a vibrational alerting means, an audible alerting means and a visual alerting means.

Optionally the invention may include a linear pressure detecting device such that the magnitude of the pressure differential between the pressure of the contents of a waste container and atmospheric pressure is derived, and not simply a logical indication of an excess pressure condition.

Optionally the invention may measure, detect or otherwise deduce the pressure within a waste container by way of measurement of a force generated by the difference between the pressure in the interior of the waste container and the pressure at a second point. The pressure at the second point may be the local atmospheric pressure or it may be some other pressure.

Optionally the invention may provide an extension to the alert means so as to alert the presence of an excess pressure condition to a person or persons other than the ostomate or may provide such an alert to a further system such as a nurse call system as might be used in a hospital or care-home environment.

Optionally the invention may be partly or completely powered by other than electrical means such as but not limited to a mechanical energy storage means such as a mechanical main sphng of the type generally used in mechanical clocks. An example of such an embodiment is where power is derived from a mechanical main spring, the energy from which is permitted to drive a vibrational clockwork motor in the event of an excess pressure condition.

Optionally the invention may entirely be without the electronic control module described hereinbefore or may lack any substantial form of such electronic control module. For example, in an embodiment broadly similar to the first embodiment and as illustrated in Figures 1, 2 and 3, the pressure switch 10, the battery 15 and the vibrator motor 16, as shown in Figure 2 may simply be electrically connected in series such that a vibrational alert is generated for the duration of closure of the pressure switch contacts 13.

Optionally the invention may generate an alert according to the duration of an extended period of excess pressure detected in a waste container. In this manner for example short duration transient instances of excess pressure might be ignored whilst longer instances of excess pressure might generate an alert.

Optionally the invention may generate an alert according to the number of periods of excess pressure detected in a waste container.

Optionally the invention may generate an alert according to frequency of periods of excess pressure detected in a waste container.

Optionally the invention may generate an alert according to the magnitude of periods of excess pressure detected in a waste container.

Optionally the invention may generate an alert according to a complex function of the pressure detected in a waste container. Such a complex function may include but is not limited to a function of the duration or durations of periods of excess pressure conditions, the number of excess pressure conditions, the frequency of excess pressure conditions, the magnitude of excess pressure conditions and the form of the detected time-varying pressure.

Optionally the invention may generate multiple types of alert in order to provide an indication of different types of excess pressure events. This for example might provide a low amplitude of vibrational alert upon detection of an excess pressure condition above a first pressure threshold and a high amplitude of vibrational alert upon detection of an excess pressure condition abovea second pressure threshold; the second pressure threshold being greater than the first pressure threshold. In this way the perceived severity of the alert is indicative of the severity of the excess pressure condition. A further example would be to generate alerts of different seventies according to the duration of a detected excess pressure condition. In this way the perceived severity of the alert might increase after a period of time if the cause of the excess pressure condition had not been removed. Such multiple types of alert may be generated according to any of the factors previously described including but not limited to being generated according to a complex function of the pressure detected.

Optionally the invention may incorporate a plurality of pressure detecting devices. The resulting plurality of detected values of pressure may be used in any manner in order to achieve the required of functionality of the invention. For example multiple pressure detecting devices may be employed in order to detect the pressure at multiple points in the arrangement of waste containers Such a configuration may provide a contingency in the event that a part of the arrangement of waste containers becomes isolated from another part of the arrangement in terms of flow of waste from the stoma, by way for example of a pipe forming part of the arrangement becoming inadvertently crushed. Therefore it would be possible for an alert to be generated because of the occurrence of an excess pressure condition in any of the isolated parts of the arrangement.

Optionally the invention may make use of a consumable part which is used to contain the waste product such that in normal operation no pal of the invention other than the consumable part will be exposed to the waste from the stoma. The use of such a consumable part will enable this part t6be replaced periodically in order to eliminate any need for cleaning or decontaminating of parts of the invention which have been in contact with waste from the stoma. This feature will be advantageous for reasons of ease of cleaning, maintenance and management.

The invention may take the form of a single physical unit or of a plurality of physical units some or all of which may be physically connected together. Communication between some or all of such a plurality of units may be achieved by any means including but not limited to electrical means, radio frequency electromagnetic means, optical means and mechanical means.