GB2418617A

GB2418617A - Bladder regulating mechanism

Info

Publication number: GB2418617A
Application number: GB0513089A
Authority: GB
Inventors: Edward Ernest Jakeman
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-08-10
Filing date: 2005-06-28
Publication date: 2006-04-05
Anticipated expiration: 2025-06-28
Also published as: GB0504792D0; GB2418617C; GB2418617C2; GB0417710D0; GB2418617B; GB0513089D0

Abstract

A mechanism for initiating and maintaining cyclic refilling and emptying of a bladder 1 comprises: a tube 3 joining a catheter 2 to a sealed drainage bag 10, the tube having a section of reduced bore which is formed into an inverted U-shaped siphon 5; a venting conduit 6 connected to the tube between the catheter and the siphon and having a flow restriction 7 and filter 9; and a strand of material 22 within the downstream leg of the siphon to induce complete drainage of the tube and to cause the siphon action to cease. A former 15 is provided to adjust the height of the siphon relative to the bladder. An irrigating apparatus may be connected to the catheter [Figure 2]. The apparatus is supported by a floor stand or a body harness [Figure 5]. The drainage bag comprises an air/liquid separator 13.

Description

Title: Bladder regulating mechanism.

Backeround Urinary catheters are in common use for treatment of both male and female patients A catheter may be deployed in any circumstances where natural voiding of the bladder is impeded. The catheter opens a permanent drainage channel allowing urine to be discharged continuously from the bladder, but, in one respect, deployment of a catheter does not restore the full natural function of the bladder, namely, flushing The term flushing is used to denote a process whereby urine is allowed to accumulate slowly in the bladder and then to discharge suddenly, leaving an empty bladder. The significance of flushing is that urine entering the bladder from the ureters is free of bacterial contamination, the bladder may not be so Flushing therefore offers a mechanism for removing harmful bacteria from the bladder The efficacy of flushing is determined by the completeness of emptying at the close of the refilling/emptying cycle Clearly, if emptying were total, with no urine residue whatsoever, removal of bacteria would also be total at the end of each cycle. In practice, total emptying is not achievable, and the bladder walls may permanently accommodate bacteria, but the rule is clear as totality of emptying is approached, flushing action becomes increasingly efficacious as a means of scavenging the bladder Conversely, continuous dilution of the bladder contents is an ineffective means of scavenging the bladder This contention is borne out in practice, infection of the lower urinary tract being a most common complication following deployment of an indwelling catheter Furthermore, after long-term deployment of an indwelling catheter, the detrusor muscle of the bladder may become "lazy" as it is not used when the bladder is continuously drained Problems arising in the use of urinary catheters include the following Bacterial infection of the lower urinary tract Blockage, or restriction, of the catheter by blood clots or tissue debris Incomplete drainage of the bladder, producing a stagnant pool of urine in the bladder, which may lead to build-up of bacteria and to encrustation or restriction of the catheter Erratic dilution of urine, and inefficient utilisation of costly sterile water, due to water shortcircuiting in the vicinity of the catheter tip when an irrigated catheter is deployed Loss of tone in the bladder detrusor muscle The above-noted conditions have been long recognised and many attempts have been made to introduce a refilling/emptying regime during deployment of catheters However, the multiple preconditions for a satisfactory mechanism are not easily reconciled, and problems of hygiene, complexity, functional instability, intolerance of variations in individual bladder performance, and high cost, have barred such mechanisms from general use Any mechanism generating periodic refilling/emptying of the bladder must tolerate an irrigation arrangement, which may be used to admit a continuous feed of sterile water to the bladder via the catheter, usually following prostatic or other surgery. An acceptable mechanism must also accommodate differences in bladder performance between individual patients. (As the bladder fills and empties, a pattern of variation in bladder pressure is invoked, and differences in bladder pressure profiles between individual patients must be accommodated) The patient must be protected from excessive bladder pressure during normal operation, or during malfunction of the mechanism, and from trauma arising from prolonged contact between the bladder wall and the catheter The mechanism must be capable of sterilization, be effectively sealed against ingress of pathogens, be reliable in use, and be cheap enough to permit disposal after use by a single patient. Sterile water, which is costly, must be used efficiently within any irrigated version of the mechanism. Finally, the mechanism must tolerate surges of pressure (valsalva) resulting from coughing or straining by the patient, and be suitable for supervision and adjustment by general nursing staff The foregoing multiple requirements are difficult to reconcile within any one exemplar of a resolution of the problems Nevertheless, the simple and novel mechanism claimed herein meets these exacting requirements in full

Statement of invention

The invention comprises a regulating mechanism for the human bladder, actuated by kinetic interactions of fluids within an array of conduits and chambers, said mechanism operating in conjunction with a catheterized, functioning, human bladder, in a manner so as to induce and maintain an autonomic, repeating, cycle of alternate draining and refilling of the bladder The mechanism includes a permanent floor stand and a disposable, sealed, sterile unit designed for single patient use, the disposable unit comprising.

- a drainage bag incorporating, at its entrance, an air/liquid separator venting to atmosphere via a viral-grade filter, - a tube joining the catheter to the drainage bag and having formed in its length, at a defined height, an inverted U which functions as a siphon, - a conduit joining said tube, at a point upstream of the inverted U. and connecting the tube to atmosphere via an air-flow restrictor and viral- grade filter, - a shaped former supporting and defining the siphon loop and maintaining it at a fixed, but

adjustable height,

- a flexible strand within the final siphon leg to promote drainage of that leg The above-listed elements are interconnected and are related in the vertical plane in a manner such that siphonic action in the tube is initiated at a defined bladder pressure, causing the bladder to empty, and is then terminated by admission of air to the siphon loop, so allowing the bladder to refill. The cycle of filling/emptying is repeated automatically, the sealed unit remaining sterile throughout the operating cycle Advantages. (see Fig] ) The mechanism proposed in this invention meets the criteria described in "Background" above, and offers a simple, reliable, hygienic, and low-cost method of flushing the bladder by cyclical refilling/draining, using prior-art forms of Foley catheter It is claimed that cyclical refilling draining of the bladder is a potent defence against proliferation of pathogens in the urinary tract, as compared with continuous drainage of urine, or urine/ water mixture Cyclic refilling/emptying resolves the problems ofthe "lazy" bladder and catheter encrustation, and also removes the problem of irrigation water short-circuiting in the bladder, and so ensures efficient use of irrigation water The mechanism is fail-safe inasmuch as it contains no moving parts, and the simple tube connecting catheter 2 to drainage bag 10 has a wider bore throughout its length than the constriction presented by catheter 2 (Fine-bore elements ofthe mechanism are not invaded by the urine stream) AISO7 the maximum pressure which can be exerted on the bladder is determined by the height of the apex in tube 3, relative to mean bladder height, the apex height being pre-set by the medical specialist attending the patient The materials of construction and production techniques required to manufacture the apparatus are all long established in prior art for this category of medical equipment, and the mechanism, being largely comprised of plastic tubes, is cheap to manufacture. The mechanism is suitable for supply as a sealed, sterile unit, complete with cheap optional components, which provide necessary adjustments to suit different patients It comprises no moving parts, other than fluids, nor any electric, electronic, electro-mechanical, nor magnetic parts, which often are not compatible with urine, blood clots, or tissue debris

Introduction to drawings and tables.

Attached drawings illustrate design and operation of the mechanism as follows Fig I Mechanism for use in Case I & Case 3 Fig 2 Mechanism for use in Case 2 Fig. 3 Definition of vertical relations of elements, Case 1, Case 3 FiL<. 4 Definition of vertical relations of elements, Case 2.

Fig. 5 Arrangement of body-supports for elements of the mechanism, Case 3.

Fig 6 Device to aid height adjustment, Case 1, Case 2 The tables listed below summarise operational details and dimensions.

Table 1 Vertical alignments of elements, Case I & Case 3 Table 2 Sizes of elements, Case I & Case 3 Table 3 Vertical alignments of elements, Case 2 Table 4 Sizes of elements, Case 2 Table 5 Phases of operation of the refilling/draining cycle, Case I & Case 3.

Table 6 Phases of operation of the refilling/draining cycle, Case 2 Descrintion - overview.

The invention claimed is a novel mechanism, composed mainly of prior-art elements, which elements are so devised, constructed, sized, ordered in sequence, and spatially arranged that, when used in conjunction with a suitable catheter implanted in a human bladder, a cycle of alternate draining and refilling of the bladder is initiated and maintained By appropriate variation of the design, the mechanism is adaptable to the three common forms of urinary catheter treatment currently in use, viz Case 1. Use of a catheter to evacuate urine from a patient confined to bed.

Case 2. Post-operative use of a catheter requiring admission of sterile saline water to the bladder and evacuation of urine and water Case 3. Use of a catheter to evacuate urine from a patient not confined to bed The adaptation described for case 2 would also be suitable for use in conjunction with other drainable body cavities

Description - Case 1.

N B all numbering in "Description - Case 1" refers to Fig I except where otherwise stated.

The mechanism comprises a tube 3 connecting the catheter 2 to a drainage bag 10 so as to allow passage of urine from catheter 2 to drainage bag 10 Tube 3 is joined to the catheter 2 via a sterile connector 14, and, (at a defined height below the mean bladder height), joins with tube 6, which connects tube 3 to atmosphere via restrictor 7, tube 4, and filtered vent 9 After the junction with tube 6, tube 3 rises to an apex before descending to enter drainage bag 10. The apex is constrained by former 15 into, preferably, but not exclusively, semicircular shape of specific radius The bore of tube 3 is reduced where it passes over former 15, the length ofthe reduced bore section being defined Tube 3 enters drainage bag 10, (to which it is permanently sealed, via an air/water separator 13. Drainage bag 1O, which is integral with air/water separator 13, through which it is vented to atmosphere via tube 11 and filter/vent 12, is adapted for periodic manual emptying Filtered vents 9 & 12 and restrictor 7 are positioned at a high level to avoid entry of urine into these elements in the event of accidental malfunction The filtering elements of filter/vents 9 & 12 are of viral grade, competent to retain particles down to 0 4pm, and having a resistance to air flow < 2cms water gauge at 250 ml/minute flow rate Vent housings 9 & 12 are adapted to connect to an air syringe (the syringe not being part of the mechanism) Elements 3, 4, 5, 6, 7, 9, 10,1 1,1 2,1 3, 14 and 1 5 are supported and held in vertical alignment by a floor stand (not shown in Fig. 1) The relative positions of elements 3, 5, 7, 9, 12, 13 & 22 in the vertical plane are crucial to correct operation of the mechanism, as is the height of this group of elements, as a whole, relative to the mean height of the bladder Said group of elements may be aligned with mean bladder height by raising or lowering the floor stand or, more simply, by adjusting the height of the patient's bed The height of the apex in tube 3 relative to mean bladder height is of particular significance, as the difference between these two heights determines the bladder pressure at which voiding occurs. (It is important for the safety of the patient that pressure applied to the bladder by the mechanism is kept within defined limits) When setting up the apparatus for a given patient, the vertical alignment process is aided by use of a levelling device shown in Fig 6. The levelling device comprises a reservoir, A Fig 6 having a vented screw cap B Fig 6. and being connected flexibly to a manometer tube C Fig.6 and to a scale D Fig.6 The manometer scale is calibrated in 2cm intervals above and below a mean height which corresponds to a patient of average build (i e of average bladder height above the mattress) Tube C Fig.6 allows reservoir A Fig.6 to be placed optionally, on the mattress, or ( for storage) on the bedside stand. The levelling device is operated by placing the reservoir on the patient's mattress, then raising or lowering the bed (or stand) to align water level in the manometer against the required mark on the scale. Relative positions, in the vertical plane, of elements 3, 5, 7, 9, 12, 13, & 22, and of the downstream end of the reduced- bore section of tube 3, are defined in Fig 3, and typical, though not prescriptive, corresponding height values are given in Table I below The initial section of tube 3, running from catheter 2 towards the junction with tube 6 is supported and located by the patient's mattress Removable sections in each of the final two vertical legs of tube 3 are capable of substitution by similar tube-sections of greater or lesser length so as to accommodate adjustments to the heights of former 15 and drainage bag 10 The final vertical leg of tube 3 contains, in its bore, an element to aid complete draining of this leg of tube 3 between cycles. Said element may be of various materials or shapes; the preferred embodiment being a helical coil 22 of prescribed dimensions, which extends from 110 mm. vertically below the apex of tube 3, to the termination of tube 3 in drainage bag 10 The coil may be disjointed into two or more touching sections to facilitate substitution oftube sections of different lengths. Former 15 and drainage bag 10 are supported in such a manner as to allow adjustment of their heights. Sterile connectors 14 permit substitution of tube sections when setting-up the apparatus for a given patient. Similarly, tube 11 is extensible to accommodate height adjustment of drainage bag 10 The main elements of the mechanism, namely, elements 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 14, & 22, (i e. all elements other than the floor stand, levelling manometer, and support items), when in use, comprise a sealed, sterile unit of disposable form to be discarded after use by a single patient. The sealed unit is free of any trace of oil, grease, silicone lubricant, or mould- release agent, and may be manufactured, sterilized, and packaged using processes and materials well known in the current technology of medical equipment manufacturers The sealed units are available in alternative versions so as to offer a range of different lengths or bores in restrictor 7 Correct action of the mechanism in initiating and maintaining cyclical emptying/refilling of the bladder depends upon the sizes of several elements of the mechanism Typical and preferred, though not prescriptive, sizes of critical elements for Case I are listed in Table 2 below Table 1. Vertical alignments of elements. Case it. Case 3 Dimensions. mm Preferred value, (mm!.Case I Preferred value. (mm! Case 3 A 50 50 B 200 200 _ - 670 560 _ 860 400 E] I 0 I 10 F 120 120 H 565 400* Datum Datum * To accommodate this dimension in case 3, restrictor 7 is aligned horizontally and is level with filter/vent 9 Fig I Table 2 Tvpical sizes of elements. Case 1 & Case 3. (Numbering refers to Filet Element Dimension Value (mm) Tube 3 Bore 6 0 Bore over former 15 4 0 Length of reduced bore over former 15 150 Length from catheter to junction with tube 6 500 (min) Tube 6 Bore 8 0 Tube 11 Bore 4 0 Restrictor 7 Bore 0.75 Length of bore 75

_

Coil 22 Pitch of helix 18 Outside diameter of helix 6 0 Wire diameter 105 Former 15 Radius of curvature 32 ODeration - Case I N.B. All numbering in "Operation - Case 1" refers to Fig I Before use the mechanism is adjusted to the individual needs of the patient Said adjustment comprises selecting an appropriate catheter 2 and restrictor 7, setting the height of drainage bag 10, setting the height of adjustable former 15, installing tube-sections of appropriate length in tube 3, selecting a manometer scale height, and adjusting floor stand (or bed) height to align bladder height with the selected manometer scale setting Once catheter 2 is installed in the bladder 1, urine passes through the catheter 2 into tubes 3 and 6, and urine level rises in the vertical sections of these tubes, accompanied by an increase in pressure in the bladder Due to natural elasticity of the bladder, said increase in pressure is accompanied by an increase in the size of the bladder and in the volume of urine contained in it Increase in urine level and pressure continues until urine, flowing acropetally in tube 3, overflows the apex, thereby initiating siphonic action in the final vertical leg of tube 3 As a result of siphonic action, pressure in the section of tube 3 upstream of former 15 falls below atmospheric pressure and this reduction in pressure is transmitted to the bladder I and to tube 6. Being of small capacity, tube 6 rapidly empties of urine, and thereafter air flows via filter/vent 9, tube 4, restrictor 7 and tube 6 into tube 3, and thence into the air/liquied separator at drainage bag 10 An unrestricted flow of air from atmosphere into tube 3 would impair the action of the siphon; and restrictor 7 functions to restrain flow of air from atmosphere to tube 3, the restrictor being sized in bore and length to avoid such impairment Once flow of urine from the bladder stops, air flowing via tube 6 into tube 3 largely replaces urine in tube 3 and siphonic action ceases At the instant when urine flow stops pressure in the bladder falls for a brief moment to less than atmospheric pressure, which encourages total evacuation of the bladder, the extent and duration of pressure reduction being governed by the dimensions of restrictor 7 During emptying of the bladder air drawn into tube 3, as described above, enters the air/water separator at drainage bag 10, separates from urine by the action of gravity, and vents to atmosphere via tube 11, and filtered vent 12 On cessation of siphonic action, urine levels once more begin to rise, and the cycle of refilling/emptying of the bladder is repeated When flow of air and urine in tube 3 has halted, some urine remains suspended in that section of tube 3 leading from the siphon apex to drainage bag 10. Said urine gradually drains under the influence of the helical wire 22 present in this section of tube 3 Phases of the refilling/draining cycle are summarised in Table 5 below For clarity, Table 5 shows only primary fluid interactions; the full course of each fluid movement not necessarily being shown Durations shown are typical, not prescriptive, values Table 5. Phases of operation of the refillina/draining cycle Case 1 & Case 3.

Phase Primary fluid movements Duration (minutes! Refilling of Urine from ureters enters bladder 1, + tube 3, + tube 6 Air vents from 60+ bladder tube 6 Air vents from tube 3, via air/water separator Draining of tube Urine flows *tom bladder 1 into drainage bag 10. Urine flows from tube 6 0 10 6 into drainage bag 10 Air enters tube 6 Air vents from tube 3 Draining of Urine flows from bladder I into drainage bag 10 Air enters tube 3, via 1.10 bladder filter/vent 9, tube 4, restrictor 7 and tube 6, Air vents from tube 3 Suction applied Residual urine in tube 3 flows into drainage bag 10 Air enters tube 3 via 0 15 to bladder filter/vent 9, tube 4, restrictor 7, and tube 6 Air vents from tube 3

Description - Case 2

N B All numbering in "Description - Case 2" where not otherwise stated, refers to Fig 2 The apparatus described above for Case I may be adapted for use in Case 2 Modifications required to adapt the mechanism for Case2 are shownaselements4, 14, 17, 18, 19,&20 These elements comprise an apparatus for supplying a regulated feed of sterile saline solution (referred to hereinafter as "water") to the bladder The apparatus consists of a sealed, renewable water bag 17, flow regulator 18, combined drip feed indicator/air separator 19, and tube 4, (which connects tube 20 through air separator 19 to filter/vent 9) Elements 4, 5, 6, 7, 9, IO, 11, 12, 13, 14, 15, 17, 18, 19, 2O, & 22 are supported and held in vertical alignment by a floor stand (not shown) The relative position of elements 3, 5, 7, 9, 12, 13, 18, 19 & 20 in the vertical plane are crucial to correct operation of the mechanism, as is the height of this group of elements relative to the mean height of the bladder Said group of elements may be aligned to mean bladder height by raising or lowering the floor stand, or, more simply, by adjusting the height ofthe patient's bed A manometer may be used to assist height alignment as described above in "Description - Case I Relative positions of elements 3, 5, 7, 9, 12, 13, 19, & 20, and of the downstream end of the reduced-bore section of tube 3, in the vertical plane, are defined in Fig 4. Typical, though not prescriptive, corresponding height values for Case 2 are given in table 3 below The initial section of tube 3 running from catheter 2 towards tube 6 is supported and located by the patient's mattress. The main elements ofthe mechanism, namely; items 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 14, 17, 18, 19, 2O, &, 22, (i e. all elements other than the floor stand, levelling manometer,, and support items), when in use, comprise a sealed, sterile unit of disposable form to be discarded after use by a single patient.

The sterile elements are free of any trace of oil, grease, silicone lubricant, or mould-release agent, and may be manufactured, sterilized, and packaged using processes and materials well known in the current technology of medical equipment manufacturers Correct action of the mechanism in initiating and maintaining cyclical emptying/refilling of the bladder depends upon the sizes of several elements of the mechanism. Typical and preferred, though not prescriptive, sizes of said elements for Case 2 are listed in Table 4 below. Elements 3, 5, 7, 9, IO, 11, 12, 13, 14, 15, & 22, are identical, in form and function, to those same elements as described above in Case 1, which are shown bearing these same numbers in both Fig I and Fig 2, and the descriptions given to those elements in "Description - Case 1" above apply also to Case 2 Table 3. Vertical alignments of elements. Case 2.

Dimension Preferred value (see Fig. 4). (mm). A 50 B 200 C 670 D 860 E 110 F 120 G 680

X DATUM

Table 4. Tvaical sizes of elements, Case 2. (Numbering refers to Fi. 2).

Element Dimension Value (mm.)

_

Tube 3 Bore 6 0

_

Bore over former 15 4 0 Length of reduced bore over former 15 150

_ _

Length from catheter to junction with 500 (min) element 6, Tube 11 Bore 4 0 Tube 20 Bore 8 0 Tube 6 Bore 8 0 Restrictor 7 Bore 0 75 Length of bore 75 Coil. 22 Pitch of helix 18 Outside diameter of helix 6 0 Wire diameter 1 05 Former I S Radius of curvature 32 ODeration - Case 2.

N B All numbering in "Operation - Case 2" except where otherwise stated, refers to Fig 2 Before use the mechanism is adjusted to the individual needs of the patient This adjustment comprises selecting an appropriate catheter, setting the height of drainage bag I O. setting the height of adjustable former 15, installing tube-sections of appropriate length in tube 3, deciding the water flow rate, and adjusting floor stand (or bed) height to align bladder height with the selected manometer scale setting. With catheter 2 installed in the bladder, a full sterile water bag 17 is installed on the floor stand and is connected to flow regulator 18 The flow regulator] 8 is turned on and adjusted to admit water to tube 20 at the required feed rate, as indicated by the drip feed device 19 Water passes via the catheter into the bladder where it mixes with urine Water and urine accumulate in the bladder, and in the vertical section of tube 3 leading to the apex, rising in each tube in response to increasing bladder pressure, until overflow occurs at the apex of tube 3 From this point, except that flow from bladder I consists of a mixture of urine and water, operation of the mechanism is identical with that described above in "Operation - Case 1 " Phases of the refilling/draining cycle for Case 2 are summarised in Table 6 below. For clarity, Table 6 shows only primary fluid interactions, the full course of each fluid movement not necessarily being shown Durations are typical, not prescriptive, values Table 6. Phases of operation of the refilling/draining cycle - Case 2.

Phase Primary fluid movements Duration | (minutes) Refilling of bladder Urine from ureters enters bladder I and tube 3 Water from 30+ supply bag enters bladder I + tube 3, Air vents to atmosphere from tubes 3, 20 Draining of tube 6 Urine/water mixture flows from bladder into drainage bag 10 0 10 Water flows from tube 6 into drainage bag 10 Air enters tube 6.

Air vents from air/liquid separator at drainage bag 10

_

Draining of bladder Urine/water mixture flows from bladder] into drainage bag 10 I. 10 Air enters tube 3 and separator via filet/vent 9, tube 4, restrictor 7, and tube 6. Air vents from air/liquid separator Suction applied to Urine/water mixture in tube 3 flows over apex into drainage bag 0.15 bladder 10. Air enters tube 3 and separator via filter/vent 9, tube 4, restrictor 7, and tube 6 Air vents from air/liquid separator

Description - Case 3.

To permit a measure of mobility in the patient, adaptations are required to the apparatus described above in "Description - Case 1" The floor stand used to support and locate elements 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 14, & 15, Fig. I is replaced by supports attached to the patient's body Said supports are shown in Fig 5 and comprise necklace A, "Sam Browne" belt and shoulder strap B/B2, thigh garter C, and lower-leg garters D & E. Those elements of the mechanism restrained and located vertically by said supports are as follows SUDDOrt (Films) Elements suDDorted (numbers refer to Filet) A 4,6,7,9, 11,12 Be 5, 15 B2 3, 6, 11 C 3,6, 11 D+E 3, 10, 11, 13 Said supports are arranged so as to maintain the vertical spacing of elements as defined in Fig.3, and listed in Table I above, for Case 3 The means of attachment at supports BY & C permit adjustment of height All parts of the mechanism supported by the patient's body are capable of transfer to an adjustable floor stand when the patient retires to bed Said transfer of elements from body to floor stand is phased to correspond to the grouping of elements on the body support system, i.e. Phase Support element transferred (Fig. 5). 1 A B.

3 B2,C 4 D, E. Vertical height settings of elements, whether supported by the patient7s body, or by the floor stand, are those defined in Fig. 3 and Table I For Case 3. Element 10 Fig. I may be modified to be more suitable to attachment to a leg support Elements 3, 6, 7, 9, 11, 12, 13, 14, 15, & 22 Fig. 1, in both form and function, are as described above in "Description - Case 1 " The location of element 7 is altered in Case 3 to orient it horizontally and level with element 9 (element 4 being modified to suit) Apart from the above-noted adaptations, the description given in Case I applies equally to Case 3.

Oneration - Case 3 Before use the mechanism is adjusted to the individual needs of the patient, said adjustment being carried out by the medical specialist, with the patient in a standing position This adjustment comprises fitting and adjusting body support items A, B', B2, C, D, & E, Fig 5, selecting an appropriate catheter 2 Fig 1, and restrictor 7 Fig. 1, adjusting height of drainage bag 10 Fig. 1, setting the height of former 15 Fig I, installing tube sections of appropriate length in tube 3, Fig 1, and initially mounting elements of the mechanism on their respective supports The medical specialist also sets-up and adjusts the patient's floor stand. Operation is then identical with that described in "Operation - Case 1" above

Claims

CLAIMS I claim.

Claim 1 A regulating mechanism for the human bladder, operating in conjunction with a catheterized bladder in a manner so as to induce and maintain an autonomic, repeating cycle of alternate draining and refilling of the bladder, the mechanism including a permanent floor stand and a sterile sealed unit of disposable form suitable for single patient use, the sealed unit comprising a sealed drainage bag incorporating at its entrance an air/liquid separator arranged so as to vent air to atmosphere via a viMI grade filter/vent, a tube of defined bore size joining through hermetic re-usable connectors the catheter and drainage bag and having formed in its length at a defined height relative to mean bladder height an inverted U arranged so as to operate as a siphon, a conduit of defined bore size joining and hermetically sealed to said tube at a point prior to the inverted U and connecting the tube to atmosphere at a defined height via a flow restrictor and a viral grade filter/vent, a shaped former supporting and defining the siphon loop so arranged as to permit adjustment of its height relative to mean bladder height, and a flexible strand suspended within the vertical section of the tube leading into the airAiquid separator and drainage bag, the arrangement and interconnection of these defined elements being such that siphomc action in the tube is initiated at a defined bladder pressure, causing the bladder to empty, and is then terminated by admission of air to the tube upstream of the siphon loop, said admission of air working in conjunction with the strand present in the downstream siphon leg to induce draining of liquid from the tube and thereby to cause siphonic action to cease, so allowing the bladder to refill; the sealed unit remaining sterile throughout the operating cycle Claim
2 A bladder regulating mechanism according to claim 1, in which said tube, in the region of its apex, is reduced in bore over a defined length, and is constrained by a rigid former in a manner so as to impose on the tube a curvature of prescribed radius Claim
3 A bladder regulating mechanism according to claimsl & 2, in which the conduit linking said tube to the viral grade filter/vent, is reduced over a prescribed short section in the vicinity of the filter/vent to a prescribed, smaller, bore so as to comprise an air- flow restrictor, the dimensions of which reduced-bore section may be varied by selection from an optional range of sections in order to adapt the mechanism to an individual patient's needs Claim
4 A bladder regulating mechanism according to claims 1 - 3, in which air/water/urine and air/urine mixtures are separated at the entrance to the integral collecting bag/separating chamber by the effect of gravity, liquids entering the collecting bag at low level, and air leaving the separating chamber at high level to vent to atmosphere through an extensible conduit via a viral-grade filter/vent situated at the atmospheric interface, the height of said filter/vent relative to mean bladder height being prescribed, and the height at which fluids enter the separating chamber, relative to mean bladder height, being capable of adjustment, but during operation ofthe mechanism, being prescribed and fixed.
Claim 5 A bladder regulating mechanism according to claims I - 4, in which, whilst the mechanism is not in operation, the tube at each side of the siphon loop may be lengthened or shortened by insertion of intermediate sections of identical tube so as to accommodate variation in siphon height, said intermediate sections being connected to the tube by means of re-usable joints so constructed as to resist separation, and to be proof against ingress of pathogens.
Claim 6 A bladder regulating mechanism according to claims 1 - 5, in which within the section of tube downstream of the siphon loop, is present an element of prescribed thickness extending from a prescribed distance vertically below the apex of the loop to the downstream termination of the tube, the shape and surface properties of said element being such as to disrupt any meniscus which might otherwise form at air/liquid interfaces in the tube, and thereby to promote drainage of the tube, said element being disjointed into two or more touching longitudinal sections Claim
7 A bladder regulating mechanism according to claim 1, in which said sealed unit is free of any oil, grease, silicone lubricant, mould-release agent, or similar lubricating substance Claim
8 A bladder regulating mechanism according to claim 1, in which said viral-grade filters have prescribed, low, resistance to air flow, and retain particles down to 0 Am in size, the casings of said filters, at the atmospheric interface, being adapted to connect to a hand-held syringe Claim
9 A bladder regulating mechanism according to claims I - 8, in which an irrigating apparatus connects to the catheter, said apparatus comprising. saline supply bag, combined shut-off and flow- regulating valve, drip- feed device, sight chamber, and feed tube, and in which the outlet ofthe drip feed device connects to the feed tube through an airAiqid separator in a manner so as to allow air to vent to and from atmosphere via a viral grade filter/vent positioned at a defined height relative to mean bladder height Claim
10 A bladder regulating mechanism according to claim 9, in which the irrigating solution contains a trace, typically < 5 ppm., of a benign surfactant having the property of reducing surface tension of the irrigating solution Claim
11 A bladder regulating mechanism according to all ofthe above claims in which elements of the mechanism are supported and held in vertical alignments by a floor stand adjacent to the patient's bed, the height of the floor stand being capable of adjustment so as to provide a defined vertical alignment between said mechanism and the height ofthe patient's bladder, which adjustment may be regulated by reference to a manometer scale related to differences in patient's physiques.
12 A bladder regulating mechanism according to claims I - 8, in which elements of the mechanism are supported and held in def ned vertical alignments alternatively, by attachment to a patient's body, or by transposition to an adjustable floor stand adjacent to a patient's bed, the means of attachment to a patient's body comprising Sam Browne belt and shoulder strap, necklace, and thigh and leg garters

Claim 12 A bladder regulating mechanism according to claims I - 8, in which elements of the mechanism are supported and held in defined vertical alignments, alternatively by attachment to the patient's body, or, by transposition to an adjustable floor stand adjacent to the patient's bed, the means of attachment to the patient's body comprising. Sam Browne belt and shoulder strap, necklace, and thigh and leg garters Amendments to the claims have been filed as follows (:LAI1\4S I A regulating mechanism for the human bladder operating in conjunction with a catheterized functioning bladder m a manner so as to induce and maintain an autonomic, repeating, cycle of alternate emptying and refillhg of the bladder, the mechanism embodying a sterile, disposable, sealed unit for single-patient use comprising a drainage bag with means enabling emptying, and a flexible tube of prescribed bore sizes, which tube connects the catheter to the drainage bag via an air/liquid separator integral with the drainage bag, the air/liquid separator being so devised as to divert air to atmosphere through a first viral-grade filter, said tube, at a location intermediate between the catheter and the drainage bag, embodying an inverted U of defined length, curvature and bore, a shaped former supporting and defining the inverted U. the drainage bag and inverted t.J being located at prescribed heights relative to mean bladder height such that when the bladder has filled to capacity, the tube functions as a siphon thus emptying the bladder, said tube being branched at a point upstream of the inverted U. the branch leading vertically upwards and connecting to atmosphere through a flow restrictor and a second viral-grade filter; the second viral-grade filter and flow restnctor being of defined resistance to flow and being located at a high level relative to mean bladder height, said tube, downstream of the inverted U. containing within its bore a longitudinal strand of prescribed material and form, devised so as to induce drainage of the tube by disrupting any menisci which might otherwise form at air/liquid interfaces in the tube after the bladder has emptied 2 A bladder regulating mechanism according to claim 1, in which said tube, at the location of the inverted U. is constrained by the former which is rigid so as to impose on the tube a curvature of prescribed radius, the height of said rigid former relative to mean bladder height being adjustable in conjunction with corresponding adjustments in the length of the tube 3 A bladder regulating mechanism according to claims I & 2, in which that branch of the tube leading to atmosphere upstream of the inverted U. is reduced to a prescribed, smaller, bore over a prescribed short section of the tube upstream of, and close to, the second viral grade filter, said reduced bore section comprising the flow restrictor; the dimensions of which reduced-bore section may be varied by selection from an optional range of sections in order to adapt the mechanism to the needs of individual patients 4 A bladder regulating mechanism according to claims] - 3, in which, whilst the mechanism Is not in operation, the height of the drainage bag relative to mean bladder height is capable of adjustment in conjunction with corresponding adjustments in the length ofthe tube and ofthe conduit leading from the air/liquid separator to atmosphere Amendments to the claims have been filed as folks A bladder regulating mechanism according to clahns I -- 4, in which, whilst the mechanism Is not m operation, the tube at each side of the inverted U may be lengthened or shortened by insertion of intermediate sections of tube, said intermediate sections being connected to the tube by means of joints constructed so as to resist separation, and to be proof against ingress of pathogens 6 A bladder regulating mechanism according to claims I - 5, in which the strand extends from a prescribed distance vertically below the apex of the inverted [J to the downstream termination of the tube, said strand being disjointed mto two or more touching longitudinal sections 7 A bladder regulating mechanism according to claim 1, in which said sealed unit is free of any oil, grease, silicone lubricant, mould-release agent, or similar lubricating substance 8 A bladder regulating mechanism according to claims 1, 3, & 9, in which said viral-grade filters have prescribed, low, resistance to air flow, and retain particles down to 0 41lm in size, the casings of said filters, at the atmospheric interface, being adapted to connect to a hand-held syringe 9 A bladder regulating mechanism according to claims 1 - 8, in which an irrigating apparatus connects to the catheter in a manner so as to admit saline solution to the bladder, said apparatus comprising saline supply bag, combined strut-off end flow-regulating valve, drip feed device, sight chamber and feed tube, the sight chamber being vented to atmosphere via the second viral grade filter positioned at a defined height relative to mean bladder height A bladder regulating mechanism according to claim 9, in which the saline solution contains a trace, typically <S ppm, of a benign surfactant having the property of reducing surface tension of the saline solution 11 A bladder regulating mechanism according to all of the above claims in which elements of the mechanism are supported and held in prescribed vertical alignments by a floor stand adjacent to a patient's bed, the height of the floor stand being capable of adjustment so as to provide a defined vertical alignment between the apex of the inverted U and the mean height of a patient's bladder; which adjustment may be regulated by reference to a manometer in order to accommodate differences in patient's physiques.