SUSTAINED DRAIN SYSTEM CIRCUIT AND QUALITY CONTROL SYSTEM THEREFOR

Abstract

A sustained drain system circuit and a sustained drain quality control system are constructed in which no mechanical or electrical driving and control mechanism is required at all, siphoning automatically occurs when some volume of urine is retained in the urinary bladder by the mass of urine, its potential energy, intrinsic pressure of filling and contraction of the urinary bladder, and abdominal pressure, and sustained drain continues even with a portion with a height difference higher than a drain source. In the sustained drain system circuit, a fluid is caused to be sustainedly drained by siphoning from an intracorporeal elastic closed space that can extend and contract as a drain source. The circuit is a siphoning circuit in which an inner diameter of a pipe space is designed so that a siphoning volume condition is satisfied and the fluid is drained as filling without a gap.

Claims

1. A sustained drain system circuit in which a fluid is can be drained by a siphoning process from an intracorporeal elastic closed space that can extend and contract as a drain source, comprising: a drain guide material provided configured to drain the fluid from the drain source; a drain tube for configured to move the fluid from the drain guide material to a drain destination; and a closed retention bag as the drain destination including an open-ended drip chamber, wherein a pressure difference between the drain source and the drain destination is P and a pipeline resistance of the circuit as a whole with respect to drain of the fluid is Rall, a specified minimum volume capable of producing an initial siphoning pressure is Ps, an initial pressure difference capable of siphoning to get over an initial siphoning resistance Rs due to a first height difference H1 in a clinical loop model condition, in consideration of an actual use environment condition, and the pipeline resistance for a sustained drain is Vmin, a volume in Vmin that can fill the elastic closed space is Vo, a volume occupying a tube space of the first height difference to a siphoning boundary, where the initial siphoning pressure Ps is configured to get over a peak of the first height difference to start drain, is Vloop, an inner space amount of the drain guide material in Vloop is Vhg, an inner space amount of the drain tube in Vloop is Vht, a total inner space volume of the drain guide material is Vg and a total inner space volume of the drain tube is Vt, a relation is represented by $\text{V min = V o + V h g + V h t}\underset{¯}{\ge }\text{V g + V t > Vloop = V h g + V h t}$ , and the circuit is a siphoning circuit in which an inner diameter of a pipe space is configured so that a siphoning volume condition defined by Equation 1 is satisfied and the fluid can be drained as filling without a gap also when being drained inside the pipe space; siphoning can occur once the pressure difference P exceeds Ps balanced with the initial siphoning resistance Rs; and, even if a second height difference H2 occurring due to a loop after the first height difference H1 is present, drain can continue without a negative pressure that can be created by elasticity of the drain source.

2. The sustained drain system circuit according to claim 1, wherein the first height difference is a height difference higher than the drain source by the loop, the second height difference is one or more height differences occurring by the loop after the first height difference and midway in the circuit between the drain source and the drain destination and, in a circumstance when the first height difference and the second height differences are present, upon receipt of the initial siphoning pressure Ps the circuit is configured be in a siphoning configuration and the circuit is configured to empty of the fluid after a time.

3. The sustained drain system circuit according to claim 2, wherein a height difference resistance can be produced from the first height difference H1, a specific gravity (density) σ of the fluid from the drain source to the siphoning boundary is Rh; a height difference resistance of the drain guide material in Rh is Rhg, a height difference resistance Rht of the drain tube to the siphoning boundary is Rht, and a total of Rhg and Rht is the height difference resistance Rh; a pipeline resistance of an overall length of the drain guide material is Rg, a pipeline resistance of an overall length of the drain tube is Rt, and a resistance at the drain destination is a peripheral resistance Rp; anda length of the circuit is L, a circuit inner diameter is 2r, a flowing speed is v, and a coefficient of friction of the pipeline is λ, a pipeline resistance is represented as $\text{R = f}\left(\text{λ}\text{,L,}\text{σ}\text{,v,r}\right)=\text{f}\left(\text{L,r}\right)\text{=}\text{λ}\cdot \text{L}\cdot \text{σ}\cdot \text{v}\text{^2}/\text{4r}$ , wherein a radius of the drain guide material is rg, a radius of the drain tube is rt, a circuit length of the drain guide material to the siphoning boundary is Lhg, a circuit length of the drain tube to the siphoning boundary is Lht, an overall length of the drain guide material is Lg, and an overall length of the drain tube is Lt, a height difference resistance to the siphoning boundary by a use condition is represented as $\text{R h = R h g + R h t}$ , an actual pipeline resistance to the siphoning boundary is $\text{R loop = f}\left(\text{L hg,rg}\right)+\text{f}\left(\text{L ht,rt}\right)$ , the initial siphoning resistance Rs is a total of Rh and Rloop, that is, $\text{R s = R h + R loop}$ , the pipeline resistance Rall of the system circuit as a whole can be obtained by minimizing $\text{R all = R g + R t + R p}$ , the circuit is configured to siphon when $\text{P s}\underset{¯}{\ge }\text{R s > R all = R g + R t + R p}$ is satisfied, $\text{R s = Rh + R loop = Rhg + Rht + f}\left(\text{L hg,rg}\right)\text{+ f}\left(\text{L ht,rt}\right)\text{> R g + R t + R p}$ is satisfied and, furthermore, if the siphoning boundary is the drain tube, $\text{f}\left(\text{Lhg,rg}\right)=\text{R g}$ holds, the system circuit is set for use of the open-ended drip chamber so that $\text{R p = 0}$ , thus, $\text{P s}\underset{¯}{\ge }\text{R s = Rh+Rg + f}\left(\text{L ht,rt}\right)>\text{R g + R t}$ is satisfied.

4. The sustained drain system circuit according to claim 2, wherein the pressure difference P is configured to be a driving force of the circuit, and is a combination of a compression pressure Pc, formed of a compression pressure of the fluid retained in the elastic closed space or an internal pressure in an abdominal cavity or a pleural cavity of a living body, and a pressure Pp of a weight of potential energy of a mass of the fluid retained in the elastic closed space.

5. A quality control system for the sustained drain system circuit according to claim 2, wherein the sustained drain system circuit is configured to conform to a conformance test by an initial siphoning pressure measurement method and a simple complete draining check test method, the sustained drain system circuit is configured to be checked under the clinical loop model condition whether the sustained drain system circuit is a product that can be driven such that the initial siphoning pressure, the minimum volume, and the initial siphoning pressure can be determined.

6. The quality control system for the sustained drain system circuit according to claim 5, wherein whether the sustained drain system circuit is configured to be driven by the fluid and is configured to undergo a PDCA cycle including a reference loading test with a reference artificial urinary bladder and a reference concentrated urine sugar, and the quality control system is configured to undergo a loading marginal check method to check a limit.

7. The quality control system for the sustained drain system circuit according to claim 6, wherein the reference artificial urinary bladder is configured to have an allowance to clear a height difference of 20 cm and the pipeline resistance, and the reference artificial urinary bladder is configured to have an internal pressure of 25 cm water column when filled with 50 ml of the fluid.

8. The quality control system for the sustained drain system circuit according to claim 6, wherein the fluid that is configured to flow through the sustained drain system circuit is selected from the reference artificial urine, the reference concentrated urine sugar, and wherein the fluid is configured to comply with a specification conformance check test, a loading test, and the loading marginal check method, and the fluid is configured to determine a limit based on the initial siphoning pressure measurement method and based on the simple complete draining check test method.

9. The quality control system for the sustained drain system circuit according to claim 6, wherein factors for the initial siphoning resistance including specifications of the reference artificial urinary bladder as the drain source, properties of the reference concentrated urine sugar as the fluid, the specified minimum volume Vmin, and a diameter, length, material, and coefficient of friction of the pipeline, are all configured for modification.

10. The sustained drain system circuit according to claim 1, wherein the circuit is configured to undergo a conformance check test by a quality control system for the sustained drain system circuit, wherein the conformance check is configured to measure siphoning and configured to drain for a period of time.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0182] FIG. 1 is a conceptual diagram depicting components and general outlines of a urine collection bag circuit of a conventional product;

[0183] FIG. 2 is a conceptual diagram depicting components and general outlines of a use situation of a sustained drain system according to the present invention;

[0184] FIG. 3A to FIG. 3C are conceptual diagram depicting three states until siphoning according to the present invention;

[0185] FIG. 4A to FIG. 4C depict conceptual diagram depicting sources of driving the sustained drain system according to the present invention;

[0186] FIG. 5A to FIG. 5D depict conceptual diagrams depicting differences between the sustained drain system (SDS) circuit according to the present invention and a non-SDS circuit;

[0187] FIG. 6 is a conceptual diagram depicting sustained drain driving conditions under clinical loop model conditions according to the present invention;

[0188] FIG. 7 is a conceptual diagram depicting an initial siphoning pressure measurement method according to the present invention;

[0189] FIG. 8 is a conceptual diagram depicting a simple complete drain check method according to the present invention;

[0190] FIG. 9 is a conceptual diagram depicting the onset and temporal transitions of an automatic sustained drain system according to the present invention;

[0191] FIG. 10 is a conceptual diagram depicting practical clinical applied control of the sustained drain system circuit according to the present invention;

[0192] FIG. 11 is a conceptual diagram depicting an artificial urinary bladder and an internal pressure measuring device according to the present invention; and

[0193] FIG. 12 is a conceptual diagram depicting a quality control system of the sustained drain system circuit according to the present invention.

DETAILED DESCRIPTION

[0194] An embodiment of the present invention is described based on the drawings.

[0195] In the present embodiment, while the concept of the “sustained drain system” of the present invention is applied to urination using an indwelling bladder catheter, this is merely an example, and it goes without saying that the concept can be applied as a technique of sustainedly draining a fluid from another intracorporeal closed space as a drain source to another extracorporeal space as a drain destination.

[0196] FIG. 1 depicts general outlines of a general urine collection circuit device using an indwelling bladder catheter. As depicted in the drawing, the device has a basic structure in which urine guided from an inner bladder catheter (balloon catheter) equipped with a balloon as an indwelling bladder catheter in a narrow sense is retained via a drain tube into a urine collection bag.

[0197] FIG. 2 depicts general outlines of the sustained drain system according to the present invention when it is assumed to be used in a practical clinical situation. The system has a basic structure in which a fluid drained from a drain source as a fluid is drained into a retention bag as a drain destination via a drain tube. However, in both clinical practice and caring practice, the drain source is not limited to be at the apex, and in most cases, a first height difference is present, in which a drain guide material or a drain tube is positioned higher than the drain source. Furthermore, several second height differences are normally present.

[0198] The drawing depicts use conditions and necessary components and structures to achieve sustained drain only in a forward direction by using scientific principles of nature even if resistance by height difference is present in consideration of the use environment in a practical clinical situation.

[0199] FIG. 3A to FIG. 3C depict driving conditions and their three states when this sustained drain system (SDS) circuit is connected to an elastic closed space.

[0200] The drawings depict three states until the NCSDS satisfy [Equation 19]

[00009]$\text{P}-\text{R =}\left(\text{P p + P c}\right)-\left(\text{R h + R g + R t + R p}\right)>0$

[0201] (In the drawings, Rg is omitted).

[0202] FIG. 3A depicts a state in which in a state of

[00010]$\text{P}-\text{R < 0}$

[0203] Siphoning does not occurs and the fluid from the drain source reaches only a midway portion of the drain guide material or the drain tube and cannot be further drained.

[0204] FIG. 3B depicts an instantaneous balanced state with

[00011]$\text{P = R}$

[0205] in which the pressure difference and resistance are balanced and the fluid has reached a siphoning boundary of a first loop and will be drained with even a slight increase in pressure difference P or decrease in resistance R.

[0206] Here, a total of the volume of the fluid occupying the drain source (Vo) and the volume of the fluid occupying the drain guide material (omitted in the drawing) or the drain tube (Vloop) is Vmin, which is a necessary required minimum amount for driving the SDS circuit in this loop state. This is so called a minimum necessary amount for siphoning.

[00012]$\text{Vmin = Vo+Vloop}$

[0207] In FIG. 3C,

[00013]$\text{P}-\text{R > 0}$

[0208] Holds, the balance is lost, and the NCSDS are satisfied to cause siphoning for sustained drain. Then, once siphoning occurs and the siphoning theory acts, the fluid of the drain source is fully drained, including the fluid at the second height difference.

[0209] That is, a feature of this SDS is that once “Equation 23 (P-R>0)” is satisfied and siphoning starts in the SDS circuit, a higher pressure is not required and drain continues.

[0210] However, the SDS is actually of no help unless Rt and Rp are minimized. That is, the SDS is not a helpful product in a practical clinical situation unless the circuit is designed in advance so that siphoning occurs even with Vmin being 50 ml or smaller and the circuit can function as an SDS circuit.

[0211] By setting siphoning minimum volume is set as small as possible, 50 ml at maximum, the SDS becomes a helpful product usable for children, people with health decline, or people with decline in the function of the urinary bladder.

[0212] For use of the conventional product of the indwelling bladder catheter of the drain guide material, it is required to review the diameter of the drain tube so as to decrease Vt so that

[00014]$\text{V min}\underset{¯}{\ge }\text{V g + V t}$

[0213] For example, when calculation is made with a set of a balloon catheter and a drain tube indwelling bladder catheter currently commercially available,

[00015]$\text{V g + V t =}\pi \times 0.2\text{5}\times 0\text{.}\text{2}\text{5}\times 40\text{+}\pi \times 0\text{. 4}\text{5}\times 0.45\times 120=84.15\text{m}\text{l}$

[0214] Thus, when the current balloon catheter is used, to set Vmin at 50 ml, in an inverse operation, it is required to set the radius of the drain tube at 3.3 mm or smaller, that is, set the inner diameter of the drain tube at 6.6 mm or smaller.

[0215] FIG. 4A to FIG. 4C are to describe the internal pressure in the elastic closed space as a source of driving this system, and depict two sources of further pressures for siphoning from a state in which pressure and resistance are balanced at the instant of siphoning.

[0216] Firstly, a method of increasing potential energy by postural change is depicted in FIG. 4B.

[0217] In an actual clinical situation, this method is relevant to a motion of sitting with knees drawn up or standing to raise the urinary bladder to prevent danger on bed where the user is laying. The inventor of the present invention has also confirmed that, at the time of a second hospital stay, in a state in which the urinary bladder was fully filled with urine even with the conventional product and it was impossible to urine although desired to do so, when the inventor stood up on bed to increase potential energy, siphoning occurred even with the conventional product for draining.

[0218] Secondly, a process of an increase in internal pressure by an increase in pressure in the closed space by external pressure (abdominal pressure) or an increase in internal pressure by an inflow of the fluid into the elastic closed space is depicted in FIG. 4C.

[0219] The two states described above, that is, increasing the internal pressure and decreasing the peripheral resistance to relatively increase pressure, are driving forces of this sustained drain system.

[0220] In any case, in practice, this does not mean that only one of these states is required. By utilizing these well, it is required to manage the internal pressure P by using the urine volume of the siphoning minimum volume Vmin and the urologic muscle of the urinary bladder and other muscles.

[0221] FIG. 5A to FIG. 5D depict differences between the SDS circuit and a non-SDS circuit, that is, differences between the siphoning circuit and the non-siphoning circuit.

[0222] FIG. 5A depicts a siphoned state by the SDS circuit under the use situations and conditions in a practical clinical situation already described in FIGS. 3A to 3C.

[0223] In FIG. 5B onward, the drawings depict midway progress in which, since the diameter of the circuit is large, if retained urine is drained, by applying abdominal pressure to increase the internal pressure, from the inside of the urinary bladder through the drain guide material (balloon catheter) to get over the siphoning boundary to flow into the drain tube, urine does not drip and fall to fill the pipeline to cause siphoning, causing urine clogging and an airlocked state.

[0224] Since the diameter of the circuit is large, the pipeline is not filled. siphoning does not occur even the fluid gets over the first height difference and drips inside the pipeline. If this continues, as in FIG. 5C, the fluid flows down inside the drain tube and starts being retained at the second height difference. When the fluid is retained to some extent, the clogged state or the airlocked state in FIG. 5D occurs, and the fluid does not flow with the previous pressure. To cause the fluid to continuously flow, a strong pressure is required.

[0225] This problem due to the situation of the product actually used (two or more height differences) is not considered at all in the conventional products in view of the manufacturer side, the medical side, and the user side. The conventional products have been continuously used without any question in the practical clinical field and the field of caring, thereby causing artificial anuresis, which is a source of producing pseudo-oliguria and pseudo-heart failure.

[0226] If this is chronically repeated, the function of the urinary bladder and the urinary function are actually damaged and injured, thereby actually causing an anuria state. The user becomes in the anuria state not temporally but chronically, and is continuously cared with the product causing the illness. The possibility of improvement further decreases, and the user is caught in a vicious cycle and has to be cared with the conventional product in a lifetime.

[0227] However, nobody has been aware of and has pointed out this vicious cycle. The conventional products causing the users to be caught in the vicious cycle have been produced and circulated all across the world, thereby continuously producing artificial anuresis and iatrogenic diseases.

[0228] FIG. 6 depicts four necessary conditions for SDS (NCSDS) for the sustained drain system circuit of the present invention.

[0229] Instead of the conventional closed urine collection bag (retention bag), a closed urine collection bag including an open-ended drip chamber is used to eliminate terminal resistance. That is, “Equation 10 (Rp=0)”, which is the “first condition”.

[0230] To cause the fluid getting over the siphoning boundary to be continuously drained as directly filling the pipeline (tube) for siphoning of the entire pipeline, the diameter of the pipeline has to be small to some extent for siphoning. That is the “second condition”.

[0231] The degree of appropriateness of the diameter of the drain tube depends on the clinical loop model conditions and the density and viscosity of the fluid.

[0232] For example, when the specific gravity and viscosity of urine are changed in the immediately-postoperative oliguric phase or in the dehydrated state, or due to diabetes, nephrotic syndrome, or the like, if the drain tube is too thin, it is easily clogged. Thus, the diameter is varied to be not too small and not to be large, depending on the clinical situation and conditions for use.

[0233] It is required to find one setting, to some extent, suitable for the situations and conditions as described above.

[0234] Thus, for the meantime, the height differences and the fluid for use and its volume are set as follows. That is, it is defined that the height differences are set at 20 cm, the fluid is water, and the siphoning minimum volume is 50 ml.

[0235] In a pathological state as described above, it is required to consider the necessity for appropriate resetting by adding a further change after use in an actual clinical situation.

[0236] Furthermore, siphoning is achieved by filling the inner space of the pipeline with the fluid. For this, the among of the inner space of the drain tube is required to be smaller than the siphoning minimum volume.

[0237] “Equation 24 (Vmin>Vg+Vt)” is required, and one with an indiscriminately large inner diameter and inner space of the drain tube is not suitable as an SDS, and thus the inner diameter is limited.

[0238] As the pipeline of the circuit is thinner, resistance increases. As the length of the pipeline is longer, resistance increases.

[0239] However, in a clinical situation, when a state of laying at a spine position at the center of a bed is considered, at least a half of the lateral length of the bed and a length obtained by subtracting the height of the bag from the height of the bed are required.

[0240] Also, if the length is too tight without an allowance, it is hard to move. This is not practical unless some allowance is provided, and some more space is thus required. However, this can produce a second height difference, and the pipeline may be lower than the inflow port to the urine collection bag.

[0241] In any case, even with the first height difference and the second height difference, for siphoning and sustained drain without formation of clogging, the radius r of the drain tube is defined as maximum required in accordance with the pipeline length.

[0242] For example, when a balloon catheter as a conventional product has an inner diameter of 0.5 cm and a length of 40 cm, a drain tube has a length of 120 cm, and Vmin=50 ml, in order to allow complete siphoning to be achieved, the inner diameter of the drain tube has to be set so that

[00016]$\left(50-3.14\times 0.25\times 0.25\times 40\right)÷3.14÷120=0.11186$

[0243] Its square root is 0.33 cm=3.3 mm, and the drain tube has an inner diameter of 6.6 mm or smaller. Whether siphoning with the tube space actually filled with the fluid without a gap can be achieved is unknown unless actually tried. This is a “third condition”,

[0244] Lastly, the driving force of the pressure for siphoning depends on the internal pressure of the urinary bladder. That is, it has been already described that the internal pressure is formed of two pressures, that is, the pressure Pc including the compression pressure with the urinary bladder filled with urine and the abdominal pressure and the pressure Pp by the potential energy from the mass of the fluid in the drain source (FIG. 4A to FIG. 4C).

[0245] This pressure, represented by Equation 16 (P=Pc+Pp), is larger than the siphoning resistance Rs generated by the first height difference and so forth, siphoning automatically occurs and sustained drain starts, causing complete draining. This is a “fourth condition”.

[0246] Note that initial siphoning pressure=height difference resistance+pipeline resistance to siphoning boundary, and

[00017]$\text{Rs=Rh+Rloop=Rhg+Rht+f}\left(\text{Lhg,rg}\right)+\text{f}\left(\text{Lht,rt}\right)$

[0247] Also,

[00018]$\text{V min = V o + V loop = V o + C h g + V h t}$

[0248] FIG. 7 is a diagram for describing an initial siphoning pressure measurement method and a method of checking a sustained drain complete drain system under clinical loop model conditions, that is, when the first and second height differences are set at 20 cm at the time of drain start.

[0249] As a matter of course, if the terminal of the circuit is completed is closed, no flow occurs at all even if a fluid is poured. Also, it is difficult to flow when the drain tube is too narrow, is bent midway, or is almost clogged.

[0250] That is, although air is also a fluid and fills the inside of the pipeline from the start, its density σ is extremely smaller than a liquid fluid and thus the pipeline resistance by air is negligible. However, it is not negligible if the pipeline is not completely closed but is partially bent or the like to be almost closed actually.

[0251] If the pipeline is extremely bent or crushed at a certain point to have an almost closed portion, air produces resistance and even water as a liquid fluid cannot flow. Thus, the entire circuit is required to appropriately have the same diameter and the inner surface of the pipeline is also required to have uniform smoothness. If a test fluid is water, a pressure of (20+α) cm water column obtained by the pressure at the first height difference of 20 cm water column and the pressure by pipeline pressure by the liquid fluid to the siphoning boundary is supposed to be a siphoning pressure.

[0252] When the pressure exceeds this initial siphoning pressure, siphoning occurs. Immediately thereafter, as an inflow from the upstream tank is stopped so as not to further increase the pressure and the fluid flows without an increase in pressure, the pressure is attenuated. Even so, complete siphoning occurs and drain continues, the fluid in the drain source is completely drained from the container and the circuit for complete draining. With that, complete draining by the siphoning pressure is confirmed.

[0253] FIG. 8 depicts a simple complete drain check test method with the defined volume under similar clinical loop model conditions, which is a check test to see whether complete siphoning can be made with a fluid of 50 ml. A fluid (water) of 50 ml is poured into a PET bottle as an elastic closed space model of the drain source, and the PET bottle is hermetically sealed. The PET bottle is pressurized to the siphoning pressure measured as described above and, after initial siphoning is confirmed, complete siphoning occurs and drain continues even pressurization onto the PET bottle is stopped. The fluid is fully drained from the PET bottle, the PET bottle becomes at negative pressure to become crushed and deformed. The fluid is stopped and retained at the second height difference.

[0254] FIG. 9 schematically depicts process and progress when the sustained drain system circuit is actually used functions, in which pressure reaches the initial siphoning pressure by the urine volume retained in the urinary bladder and the abdominal pressure in a body condition at that time to automatically start drain, depicting an intermission period from production of urine until pressure reaches the initial siphoning pressure and a sustained drain period in which sustained drain starts once pressure reaches the initial siphoning pressure to cause complete draining (elimination).

[0255] One key point in the sustained drain system according to the present invention is the necessity of “understanding the urination mechanism”, “design criteria of the pipeline and others for sustained drain siphoning”, and “actual use situation reference”.

[0256] Urine is produced in the kidney at 1 ml/Kg/h. As a urination mechanism, when 200 ml to 400 ml of urine is retained in the urinary bladder, the detrusor muscle of the urinary bladder wall is pressurized and stretched. With a stimulus by the stretch receptor, micturition reflex occurs to start urination. Here, “contraction of the detrusor muscle of the urinary bladder”+“relax of the internal urethral sphincter”+“relax of the external urethral sphincter” occurs.

[0257] Urine of 200 ml, which serves as a urination stimulus and causes a sensation of needing to urinate, is retained in the urinary bladder. Before the internal pressure of the urinary bladder increases to exceed a threshold, the urine collection circuit is required to be siphoned. However, to start drain with a urine volume as minimum as possible, the resistance Rh by the first height difference H1 is not avoidable in a practical clinical use situation. Among the other three circuit resistance elements Rg, Rt, and Rp, Rg is not much allowed to be changed except the coefficient of friction, and the other resistances Rp and Rt are required to be decreased as much as possible.

[0258] Rp becomes approximately 0 as an open-ended bag in the open-ended drip chamber, and the remaining Rt is minimized as much as possible, thereby providing the function of siphoning even in a postoperative biological condition or in a wheelchair with chronic anuresis. Without this, sustained drain cannot start.

[0259] Furthermore, to measure chronological urine volume (time urine) serving as an important index of the postoperative physical state, it is required to automatically start urination even with the siphoning necessary minimum volume Vmin equal to or smaller than 50 ml.

[0260] For example, for the purpose of measurement of postoperative time urine, it is not enough to retain urine in the urinary bladder until a sensation of needing to urinate occurs with 200 ml to start urination, as is normally the case. It is required to design Vmin so that sustained drain starts with a urine volume as small as possible.

[0261] Also for siphoning, it is required to fill the urine collection circuit with a urine volume as small as possible. The most important factors for siphoning are Rh due to the presence of the first height difference H1 and the pipeline resistance Rt, which are clinically required.

[0262] It is the muscle group of the urinary bladder and other muscle groups regarding the abdominal pressure and the urine volume filling the urinary bladder that produce pressure to get over the resistance. After all, also in order to decrease the siphoning minimum necessary volume Vmin as much as possible, minimizing the resistance Rt of the drain tube as much as possible is the only way.

[0263] Rh is a height difference clinically required irrespective of whether the user lays in bed or is in a wheelchair, and cannot be omitted.

[0264] However, Rh can be decreased depending on the body state, by doing something even laying in bed. This is not a normal situation, but can trigger the conscious start of urination.

[0265] After all, no other option remains but to decrease the pipeline resistance Rt as a factor for adjusting the siphoning minimum volume Vmin. The sustained drain system cannot be controlled unless designed in advance.

[0266] Vmin is a sum of the retention volume of the urinary bladder producing a SDS driving internal pressure difference and a pipeline-filled volume for getting over the first height difference.

[0267] “Equation 28 (Vmin=Vo+Vloop=Vo+Vhg+Vht)”

[0268] Pc is a contraction pressure produced by the detrusor muscle of the urinary bladder stretched with an increase in the internal pressure by retention of urine, and requires some urine volume. Also, Pp is not produced unless some urine volume is retained.

[0269] The actual volume of the urinary bladder which actually causes pressure to reach the initial siphoning pressure varies depending on the physical state and the urinary bladder state of the SDS user at that time, varying with time and individual. After all, whenever pressure reaches the initial siphoning pressure, complete draining occurs for each time in a sustained drain period in which urination automatically occurs.

[0270] The factor for defining the initial siphoning pressure is resistance. When the use of the conventional balloon catheter as a drain guide material is assumed, if urine is collected via the open-ended drip chamber, that is, “Equation 3 (Rp=0)”, Rt is the only factor to be controlled, except Rh clinically required. By controlling Rt, siphoning is prepared and, in the sustained drain system, in each of physical states at different times, an appropriate volume of urine is retained in the urinary bladder to cause pressure to reach the initial siphoning pressure for automatic repetitive urinations.

[0271] Rt obtained by excluding the height difference resistance Rh, which is not an element of the circuit, from Rs is a determination factor for determining whether to start sustained drain when some volume of urine is retained. To cause sustained drain without putting a load on the living body as much as possible (to exclude the necessity of applying excessive abdominal pressure), it is required to automatically start sustained drain with minimum necessary resistance and a minimum urine volume for siphoning.

[0272] In the pipeline resistance, the density and flow velocity of the fluid are involved. However, the fluid density σ cannot be controlled because of depending on the concentration of urine produced. Moreover, the flow velocity is determined by the pipeline and the pressure difference accordingly, and also cannot be controlled. On the other hand, the inner diameter and the length of the pipeline can be determined in advance, and therefore can be controlled.

[0273] As described above, as for Rt, the radius and the length are key factors. Furthermore, in some cases, friction resistance λ and the density and consistency of the fluid may also be considered. In those cases, it is required to ensure capabilities and functions capable of draining dense urine due to dehydration, heart failure, renal failure, or the like or high-viscosity urine due to diabetes, nephrotic syndrome, or the like.

[0274] After all, the radius r and the pipeline length L of the pipeline define the resistance Rt and the sustained drain start urine volume Vmin, and also determine the start of SDS.

[0275] That is, two major factors for sustained drain are siphoning and pressure difference control. After all, as represented in Equation 11, the length and inner diameter (radius) of the circuit are important factors and it is no exaggeration to say that sustained drain is defined by the inner diameter.

[0276] The length and the inner diameter can be both designed in advance. If the inner diameter of the drain tube is 4 mm (radius of 2 mm) and the length is 1.2 m, Vt is approximately 15 ml.

[0277] Also to suppress occurrence of clogging of the drain tube with urine and airlock, siphoning with a thin pipeline is required. With siphoning and the pressure difference, complete draining can be made without residual urine.

[0278] From above, “Equation 12 (P-Rs>0)” is the driving force of the automatic drain system. Appropriate control and management cannot be performed at the time of manufacturing and nursing in charge of actual operation and management unless this concept of siphoning is sufficiently understood. Insufficient understanding, by extension, may become a major inhibiting factor when appropriate medical care is implemented.

[0279] FIG. 10 introduces a method for driving this SDS in an actual clinical scene.

[0280] In (4) of FIG. 10, a case is depicted in which urine is gradually retained in the urinary bladder, and the inner pressure (P2) exceeds the total resistance (R) including the first height difference.

[0281] In (5) of FIG. 10, a case is depicted in which the user applies abdominal pressure by himself/herself by pushing down, pressing the abdomen with hands, or the like.

[0282] In (6) of FIG. 10, a case is depicted in which the user changes the posture from a spine position to a lateral position to resolve the first height difference to decrease the siphoning resistance Rs.

[0283] In (7) of FIG. 10, a case is depicted in which the potential energy is increased by changing the posture from a spine position to a position with knees drawn up or a standing position.

[0284] In (8) of FIG. 10, a case is depicted in which, as a result, complete urination has been made.

[0285] FIG. 11 depicts the structure and functions of a reference urinary bladder required for the simple complete draining check test method to check whether the product conforms to the specifications and also for a loading test with the properties of a concentrated thick fluid, and also depicts a urinary bladder urine dynamic state measurement device to measure the pressure. By using the artificial urinary bladder in place of a simple PET bottle, complete discharge can be made without retention and stagnation in the second loop.

[0286] FIG. 12 depicts necessary elements when the sustained drain system circuit is fabricated, and necessary elements for planning its specifications and assuring its quality, and an overview of a quality assurance and quality control system with PDCA applied to fabricate proper medical devices and control their quality.

[0287] With this sustained drain control system, the sustained drain system circuit is properly fabricated and properly used and operated, thereby enhancing convenience in clinical control, performing proper medical care, and improving the quality of life of the users and their families.

[0288] Also, this reason, the reference artificial urinary bladder, the reference concentrated urine sugar, and the clinical loop model conditions are required to be studied. With the current circumstances accurately confirmed to serve as a base of the study, it is imperative to perform systems thinking of the purpose and target and the PDCA cycle.

[0289] In the sustained drain system of the present invention, by further contriving a urine collection tube as a drain tube in view of its material to reduce its inner diameter, length, and the coefficient of friction in consideration of the use conditions and environment, the initial siphoning resistance can be reduced, and there is a possibility of reducing the load on the urinary bladder and the body. In other words, this SDS circuit depends on how this drain tube is contrived so as to have small resistance and be light in weight and usable with ease in a clinical situation. For this purpose, by utilizing patents and know-hows regarding artificial vessels, at least low-quality tubes clogged with bloody urine do not have to be provided. That is, an ideal circuit is born like an artificial vessel almost without friction resistance and not clogged with viscous concentrated urine, urine sugar, urine protein, bloody urine, or the like even the circuit is thin to allow sustained drain.

[0290] Furthermore, the system can be used not only for urination using an indwelling bladder catheter but can be widely used as a principle and technique for sustainedly draining a fluid from another intracorporeal elastic closed space as a drain source to an extracorporeal space as a drain destination.

[0291] These principles of siphoning and system circuit have the possibility of helping construction of not only a urine collection circuit but also a catheter for discharging a postoperative waste fluid such as a pleural fluid or ascites fluid and a shunt system from the cerebral ventricle to the thoracic cavity or the abdominal cavity for treatment of hydrocephalus. A system circuit in which a certain resistance is established in advance by the length, radius, and the friction resistance in accordance with the use purpose can be used as a shunt system for hydrocephalus which automatically cause sustained drain once a certain pressure difference occurs, even if a mechanical system is not present, such as a flow-rate adjustment valve (differential pressure valve) from the cerebral ventricle to the inside of the thoracic cavity or the abdominal cavity in one direction. As the number of mechanical portions increases, the number of causes of clogging or failure increases. With the same principles, it is possible to construct a system only with a circuit, the system in which a flow does not occur at a spine position but automatic sustained drain occurs when a pressure difference occurs between the pressure in the cerebral ventricle and the pressure in the thoracic cavity or the abdominal cavity at a sitting position or a standing position.

[0292] Furthermore, in addition to the system circuit, the quality control system of the present invention according to the first aspect to the tenth aspect in FIG. 12 provides a procedure and method of analyzing use conditions in an actual use scene to provide a properly-functioning product, not limited to a medical device, in any product development, and performing product development and control conforming to the use conditions. These procedure and method are useful for any company and any product. Even without official specifications, the company itself can perform quality assurance and quality control of the product in the name of the company and can exert its existence value and accomplish a mission of the company.

[0293] The conventional products are deviated to disregard the current situations already at the first step of this control system of grasping the use conditions for checking the current state and variable factors. That is, use situations in actual medical and caring practice, for example, postoperative situations and states on the user’s side, among others, the influence of the first height difference, is not considered at all, not causing siphoning but inviting formation of clogging or an airlocked state. Although this fact may be recognized by nurses actually involved in medical care depending on the degree of experience, the current circumstances are such that how much pain the fact gives actual patients as users is not recognized and no appropriate measures are taken.

[0294] Thus, when it is defined that a pressure difference between the drain source and the drain destination is P, resistance of the fluid with respect to drain is R, a minimum volume as small as possible satisfying the elastic closed space as a drain source necessary for producing the siphoning pressure Ps as an initial pressure difference for siphoning which gets over the siphoning resistance Rs formed of the height difference resistance of the first height difference occurring by an initial loop of the loop model conditions in consideration of actual use environment conditions to start sustained drain is Vmin, and a volume occupying the tube space of the first height difference of the siphoning boundary where the pressure gets over the peak of the first height difference with the siphoning pressure Ps to start drain is Vloop, a relation between the inner space volume Vg of the drain guide material and the inner space volume Vt of the drain tube midway in the circuit is represented as

[00019]$\text{V min}\underset{¯}{\ge }\text{V g + V t > Vloop}$

[0295] The siphoning circuit is provided so that the above equation is satisfied and the inner diameter of the tube space is designed so that the fluid is drained as filling the tube space without a gap even during draining. Once the pressure difference P exceeds the Ps value balanced with the siphoning resistance Rs and satisfying “Equation 11 (Ps≥Rs=Rh+Rg+f(Lht, rt)>Rg+Rt), siphoning occurs and, even with a second height difference occurring due to a loop after the first height difference, a negative pressure is not formed and drain continues by elasticity of the drain source for complete draining.

[0296] For this purpose, in the sustained drain system circuit, actual use situations and environments are modeled, and circuit conditions for siphoning under these conditions are clarified and properly defined, specification are further defined, and quality is assured. Also, a quality control system for the sustained drain system circuit is constructed, a loading test is also performed by the quality control system, and the sustained drain system circuit is a product assured with its specifications and limitations clarified. The quality control system includes three processes of “definition of specifications”, “quality assurance”, and “specification and quality control”, and circulates these processes.