Blood purification apparatus

To provide a blood purification apparatus in which the hot-water-disinfection time can be optimized with consideration for environmental conditions. A blood purification apparatus provided with a dialyzer for giving dialysis treatment to a patient, and with a tube for introducing dialysate into or discharging drain liquid from the dialyzer. The apparatus includes a thermistor that is capable of detecting an environmental condition at a time of a hot-water-disinfection process in which the tube is disinfected with hot water or a parameter regarding the environmental condition, and an estimating device that estimates a hot-water-disinfection time required for the hot-water disinfection of the tube in accordance with the environmental condition or the parameter regarding the environmental condition detected by thermistor.

FIELD

The present teachings relate to a blood purification apparatus provided with a blood purification device for giving dialysis treatment to a patient, and with a tube for introducing dialysate into or discharging drain liquid from the blood purification device.

BACKGROUND

In general, a dialysis apparatus serving as a blood purification apparatus intended for dialysis treatment is provided with tubes, such as a dialysate introduction line and a dialysate drain line, for introducing dialysate into a dialyzer (a blood purification device) connected to a blood circuit and for discharging the dialysate containing waste products resulting from the dialysis from the dialyzer. The dialysate introduction line and the dialysate drain line are connected at the distal ends thereof to a dialysate inlet and a dialysate outlet, respectively, of the dialyzer. Furthermore, the dialysate introduction line is connected at the proximal end thereof to a dialysate-supplying device. Thus, the dialysate is allowed to be supplied to the dialyzer.

In such a blood purification apparatus, the tubes such as the dialysate introduction line and the dialysate drain line are disinfected by washing prior to the dialysis treatment. In recent years, a hot-water-disinfection process in which hot water (with citric acid) is used as a washing-and-disinfection solution has been becoming popular. As disclosed by PTL 1, for example, such a known blood purification apparatus includes a circulation tube for forming a circulation flow route that allows liquid (washing water) to circulate in the hot-water-disinfection process, a heater (a heating device) capable of heating the liquid that circulates through the circulation flow route and generating hot water that is at a temperature required for hot-water disinfection, and a thermistor (a temperature-measuring device) capable of measuring the temperature of the liquid heated by the heater. The tubes are disinfected with hot water by causing the hot water at a predetermined temperature to circulate through the circulation flow route for a period of time required for hot-water disinfection.

The above known blood purification apparatus has the following problem.

The hot-water disinfection of tubes greatly depends on environmental conditions at the time of the hot-water-disinfection process. Therefore, the hot-water-disinfection time and so forth are set such that a satisfactory level of disinfection effect can be obtained even under the worst environmental conditions. That is, assuming that environmental conditions, such as the heating function of the heater (the power-source voltage); the supply water temperature; and the ambient temperature, are all at the worst levels in terms of generating hot water suitable for hot-water disinfection, a long hot-water-disinfection time estimated for the worst conditions is set so that a satisfactory level of hot-water-disinfection effect is guaranteed.

However, the hot-water-disinfection time that is set as described above tends to be greatly different from the hot-water-disinfection time that is required under normal environmental conditions. Therefore, the hot-water-disinfection time thus set tends to be excessively long. That is, in the known technique, hot-water disinfection cannot be performed efficiently, which may increase the power consumption and the heat stress given to components such as filters provided to the tubes. Hence, to make the hot-water-disinfection process more efficient, the hot-water-disinfection time needs to be optimized with consideration for environmental conditions.

SUMMARY

The present teachings have been conceived in view of the above circumstances and provides a blood purification apparatus in which the hot-water-disinfection time can be optimized with consideration for environmental conditions.

According to the teachings herein, there is provided a blood purification apparatus provided with a blood purification device for giving dialysis treatment to a patient, and with a tube for introducing dialysate into or discharging drain liquid from the blood purification device. The apparatus includes a detecting device that is capable of detecting an environmental condition at a time of a hot-water-disinfection process in which the tube is disinfected with hot water or a parameter regarding the environmental condition, and an estimating device that estimates a hot-water-disinfection time required for the hot-water disinfection of the tube in accordance with the environmental condition or the parameter regarding the environmental condition detected by the detecting device.

According to the teachings herein, the blood purification apparatus taught herein further includes a calculating device that calculates, from the hot-water-disinfection time estimated by the estimating device, a completion time of the hot-water disinfection or a remaining time before a completion of the hot-water disinfection.

According to the teachings herein, the blood purification apparatus taught herein further includes a circulation tube for forming a circulation flow route that allows liquid to circulate in the hot-water-disinfection process, a heating device capable of heating the liquid circulating through the circulation flow route and generating hot water at a temperature required for hot-water disinfection, and a temperature-measuring device capable of measuring a temperature of the liquid heated by the heating device. The detecting device is the temperature-measuring device, and a value measured by the temperature-measuring device is the parameter regarding the environmental condition.

According to the teachings herein, in the blood purification apparatus taught herein, the heating device and the temperature-measuring device are provided to the circulation flow route.

According to the teachings herein, in the blood purification apparatus taught herein, the temperature-measuring device is provided on a downstream side of the heating device.

According to the teachings herein, in the blood purification apparatus taught herein, the temperature-measuring device is provided on the downstream side of and near the heating device.

According to the teachings herein, in the blood purification apparatus taught herein, the estimating device has a table created for obtaining the hot-water-disinfection time from the value measured by the temperature-measuring device. The table is prepared in accordance with a correlation, under a certain environmental condition, between the value measured by the temperature-measuring device and a temperature at a position of the circulation flow route that is on a downstream side of the temperature-measuring device and on the upstream side of the heating device.

According to the teachings herein, in the blood purification apparatus taught herein, the estimating device has a table created for obtaining the hot-water-disinfection time from the value measured by the temperature-measuring device. The table is prepared in accordance with a correlation, under a certain environmental condition, between the value measured by the temperature-measuring device and a temperature at a position of the circulation flow route that is on a downstream side of the temperature-measuring device and on the upstream side of and near the heating device.

According to the teachings herein, in the blood purification apparatus taught herein, the estimating device has a table created for obtaining the hot-water-disinfection time from the value measured by the temperature-measuring device. The table is prepared in accordance with a correlation, under a certain environmental condition, between the value measured by the temperature-measuring device and a temperature at a position of the circulation flow route where a rise of the temperature with the heating by the heating device is slow.

According to the teachings herein, in the blood purification apparatus taught herein, at least one of the environmental conditions summarized in the table is identifiable from the value measured by the temperature-measuring device.

According to the teachings herein, the blood purification apparatus includes the detecting device that is capable of detecting the environmental condition at the time of the hot-water-disinfection process in which the tube is disinfected with hot water or the parameter regarding the environmental condition, and the estimating device that estimates the hot-water-disinfection time required for the hot-water disinfection of the tube in accordance with the environmental condition or the parameter regarding the environmental condition detected by the detecting device. Therefore, the hot-water-disinfection time can be optimized with consideration for the environmental conditions.

According to the teachings herein, the blood purification apparatus further includes the calculating device that calculates, from the hot-water-disinfection time estimated by the estimating device, the completion time of the hot-water disinfection or the remaining time before the completion of the hot-water disinfection. Therefore, the operator can recognize the completion time of the hot-water-disinfection process or the remaining time before the completion of the hot-water-disinfection process.

According to the teachings herein, the blood purification apparatus further includes the circulation tube for forming the circulation flow route that allows the liquid to circulate in the hot-water-disinfection process, the heating device capable of heating the liquid circulating through the circulation flow route and generating hot water at a temperature required for hot-water disinfection, and the temperature-measuring device capable of measuring the temperature of the liquid heated by the heating device. The detecting device is the temperature-measuring device, and the value measured by the temperature-measuring device is the parameter regarding the environmental condition. Therefore, the required hot-water-disinfection time can be estimated by using the temperature-measuring device that is intended for measuring the temperature of the tube during the blood purification treatment.

According to the teachings herein, the heating device and the temperature-measuring device are provided to the circulation flow route. Therefore, the required hot-water-disinfection time can be estimated by using the heating device and the temperature-measuring device.

According to the teachings herein, the temperature-measuring device is provided on the downstream side of the heating device. That is, the temperature-measuring device is provided at a position where the rise of the temperature with the heating by the heating device is quick. Hence, the required hot-water-disinfection time can be estimated more quickly.

According to the teachings herein, the temperature-measuring device is provided on the downstream side of and near the heating device. That is, the temperature-measuring device is provided at a position where the rise of the temperature with the heating by the heating device is quicker. Hence, the required hot-water-disinfection time can be estimated much more quickly.

According to the teachings herein, the estimating device has the table created for obtaining the hot-water-disinfection time from the value measured by the temperature-measuring device. The table is prepared in accordance with the correlation, under a certain environmental condition, between the value measured by the temperature-measuring device and the temperature at the position of the circulation flow route that is on the downstream side of the temperature-measuring device and on the upstream side of the heating device (or on the upstream side of and near the heating device) (or the temperature at the position of the circulation flow route where the rise of the temperature with the heating by the heating device is slow). Therefore, the required hot-water-disinfection time can be estimated more precisely and more smoothly.

According to the teachings herein, at least one of the environmental conditions summarized in the table is identifiable from the value measured by the temperature-measuring device. That is, the estimation can be made without the consideration for the other environmental conditions summarized in the table. Therefore, the required hot-water-disinfection time can be estimated more precisely and more quickly.

DETAILED DESCRIPTION

Embodiments of the present teachings will now be described specifically with reference to the drawings.

A blood purification apparatus according to an embodiment is intended for purifying the blood of a patient while extracorporeally circulating the blood and is applied to a hemodialysis apparatus used in hemodialysis treatment. The hemodialysis apparatus basically includes, as illustrated inFIG. 1, a blood circuit1(an arterial blood circuit1aand a venous blood circuit1b), a dialyzer2serving as a blood purification device, a dialysate introduction line L1connectable to the dialyzer2and allowing dialysate to be introduced into the dialyzer2, a dialysate drain line L2connectable to the dialyzer2and allowing drain liquid from the dialyzer2to be discharged, connecting tools C1and C2(each being a connecting tool called “coupling”), a control device10, an estimating device11, and a calculating device12.

The blood circuit1basically includes the arterial blood circuit1aand the venous blood circuit1bthat are each made of a flexible tube. The dialyzer2is provided between the arterial blood circuit1aand the venous blood circuit1b.The arterial blood circuit1ais provided at the distal end thereof with a connector a to which an arterial puncture needle is connectable, and at a halfway position thereof with a peristaltic blood pump3. The venous blood circuit1bis provided at the distal end thereof with a connector b to which a venous puncture needle is connectable, and at a halfway position thereof with an air-trap chamber4for bubble removal.

When the blood pump3is activated with the arterial puncture needle and the venous puncture needle being stuck in the patient, the blood of the patient flows through the arterial blood circuit1ainto the dialyzer2, where the blood is purified and ultrafiltered. Then, the blood flows through the venous blood circuit1bwhile undergoing bubble removal in the air-trap chamber4, and returns into the body of the patient. Thus, the blood of the patient can be purified by the dialyzer2while being made to extracorporeally circulate through the blood circuit.

The dialyzer2has, in a housing thereof, a blood introduction port2a,a blood delivery port2b,a dialysate introduction port2c,and a dialysate delivery port2d.The proximal end of the arterial blood circuit1ais connected to the blood introduction port2a.The proximal end of the venous blood circuit1bis connected to the blood delivery port2b.The dialysate introduction port2cand the dialysate delivery port2dare connected to the dialysate introduction line L1and the dialysate drain line L2with the connecting tools C1and C2interposed therebetween, respectively.

The dialyzer2houses a plurality of hollow fibers. The hollow fibers each provide a blood flow route thereinside. A space between the outer peripheral surface of each of the hollow fibers and the inner peripheral surface of the housing serves as a dialysate flow route. The hollow fibers each have a number of very small holes (pores) extending therethrough from the outer peripheral surface to the inner peripheral surface, thereby forming hollow fiber membranes. Hence, waste products, excessive water, and the like contained in the blood are allowed to penetrate through the membranes into the dialysate.

The dialysate introduction line L1and the dialysate drain line L2are connected to a duplex pump5that delivers the dialysate prepared to have a predetermined concentration to the dialyzer2and discharges waste products and the like together with the dialysate from the dialyzer2. Specifically, the duplex pump5is provided over the dialysate introduction line L1and the dialysate drain line L2. When the duplex pump5is activated, the dialysate can be introduced into the dialyzer2through the dialysate introduction line L1while being discharged from the dialyzer2through the dialysate drain line L2.

The dialysate introduction line L1is provided with electromagnetic valves V1and V2and filtration filter7. The dialysate to be introduced into the dialyzer2can be filtered by the filtration filter7, and the flow route of the dialysate is closable or openable with an arbitrary timing by the electromagnetic valves V1and V2. On the other hand, the dialysate drain line L2is provided with electromagnetic valves V3and V4. The flow route is closable or openable with an arbitrary timing by the electromagnetic valves V3and V4.

The dialysate introduction line L1and the dialysate drain line L2are each connected to bypass lines L4and L5on a side of the duplex pump5that is nearer to the dialyzer2and on the other side of the duplex pump5. The bypass lines L4and L5are each communicable with the dialysate introduction line L1and with the dialysate drain line L2. The bypass lines L4and L5are provided with electromagnetic valves V5and V6, respectively, that are capable of opening and closing the respective flow routes. The dialysate drain line L2is connected to a detour line L3that detours the duplex pump5. The detour line L3is provided with an ultrafiltration pump6. Hence, when the ultrafiltration pump6is activated while the blood of the patient is made to extracorporeally circulate through the blood circuit, ultrafiltration in which water is removed from the blood flowing through the dialyzer2can be performed.

The dialysate introduction line L1and the dialysate drain line L2according to the present embodiment are provided at the distal ends thereof with the connecting tools C1and C2, respectively. When the connecting tools C1and C2are connected to each other (seeFIG. 3), the dialysate introduction line L1and the dialysate drain line L2form a closed circuit. When the connecting tools C1and C2thus connected are disconnected from each other, the closed circuit is opened, allowing the connecting tools C1and C2to be connected to the dialyzer2(seeFIG. 1).

Referring toFIG. 3, in a hot-water-disinfection process, the bypass line L5according to the present embodiment serves as a circulation tube for forming a circulation flow route through which liquid (water) can be made to circulate. Specifically, as illustrated inFIG. 3, a circulation flow route for allowing the liquid to circulate therethrough can be formed by connecting the connecting tools C1and C2to each other to form a closed circuit, with the electromagnetic valves V1and V4being closed and the electromagnetic valve V6being open (the state is changeable by opening or closing each of the electromagnetic valves V2, V3, and V5with an arbitrary timing, between a state where the bypass line L4forms part of the circulation flow route and a state where the flow route on the side having the connecting tools C1and C2forms part of the circulation flow route).

The dialysate introduction line L1is further provided with a heater8serving as a heating device and a thermistor9serving as a temperature-measuring device between the point of connection thereof to the bypass line L5(the circulation tube) and the point of connection thereof to the duplex pump5. When the heater8is activated by being powered, the liquid circulating through the circulation flow route formed by the bypass line L5(the circulation tube) is heated, whereby hot water at a temperature required for hot-water disinfection can be generated. The thermistor9is a sensor capable of measuring the temperature of the liquid heated by the heater8.

As illustrated inFIG. 2, the hemodialysis apparatus according to the present embodiment includes a dialysis-apparatus body H. The dialysis-apparatus body H includes a monitor screen M for displaying information such as settings for the treatment and the patient's condition during the treatment, a syringe pump S, a warning lamp R, and so forth. The dialysis-apparatus body H is provided with the duplex pump5, the blood pump3, and the tubes such as the dialysate introduction line L1and the dialysate drain line L2. Note that the term “tubes” according to the present embodiment include not only the dialysate introduction line L1for introducing the dialysate into the dialyzer2and the dialysate drain line L2for discharging the drain liquid from the dialyzer2but also other tubes through each of which the dialysate or the drain liquid flows.

The control device10is a microcomputer or the like provided in the dialysis-apparatus body H and is capable of controlling the opening/closing of the electromagnetic valves (V1to V6) before, after, and during the treatment, and the operations of actuators provided for the duplex pump5, the ultrafiltration pump6, and others. Furthermore, the control device10is capable of controlling the heater8during the dialysis treatment to heat the dialysate to be introduced into the dialyzer2to an appropriate temperature while controlling the thermistor9to measure the temperature of the dialysate and controlling the operation of the heater8.

In particular, at the time of the hot-water-disinfection process in which the tubes are disinfected with hot water, the control device10according to the present embodiment controls the opening and closing of the electromagnetic valves (V1to V6) to form the circulation flow route illustrated inFIG. 3, and activates the heater8, whereby hot water at a temperature required for hot-water disinfection can be generated. The present embodiment employs the circulation tube (the bypass line L5) for forming, at the time of the hot-water-disinfection process, the circulation flow route that allows the liquid to circulate therethrough, the heating device (the heater8) capable of heating the liquid circulating through the circulation flow route and thus generating hot water at a temperature required for hot-water disinfection, and the temperature-measuring device (the thermistor9) capable of measuring the temperature of the liquid heated by the heating device. Hence, the temperature of the liquid heated by the heater8while being made to circulate through the circulation flow route can be measured in real time by the thermistor9.

The blood purification apparatus according to the present embodiment includes the detecting device (the thermistor9) that is capable of detecting environmental conditions at the time of the hot-water-disinfection process, in which the tubes provided in the dialysis-apparatus body H are disinfected with hot water, or parameter regarding the environmental conditions; the estimating device11that estimates the hot-water-disinfection time required for the hot-water disinfection of the tubes in accordance with the environmental conditions or the parameter regarding the environmental conditions detected by the detecting device; and the calculating device12that calculates the completion time of the hot-water disinfection from the hot-water-disinfection time estimated by the estimating device11.

The environmental conditions at the time of the hot-water-disinfection process refer to conditions for generating hot water at a temperature required for hot-water disinfection performed by heating the liquid in the tubes (the circulation flow route in the present embodiment) by using the heater8(the heating device). For example, the followings can be named: the power-source voltage (the input voltage of the heater8), the supply water temperature (the temperature of water to be introduced from the dialysate introduction line L1), the ambient temperature (the temperature around the dialysis-apparatus body H), and so forth. The parameter regarding the environmental conditions refer to any parameter directly or indirectly affected by the above environmental conditions. For example, the followings can be named: the value measured by the thermistor9(the temperature-measuring device), the thermal capacity of the heater8, the capacity of the tubes, the individual differences among components provided to the tubes (the difference in pressure loss, the state of fitting of assembled components, etc.), and so forth.

The detecting device according to the present embodiment is the thermistor9(the temperature-measuring device) capable of measuring the temperature of the liquid in a tube (the water introduced into the dialysate introduction line L1) that is heated by the heater8(the heating device). The detecting device is capable of detecting the temperature of the liquid heated by the heater8, the temperature being a parameter affected by the environmental conditions. That is, according to the present embodiment, the detecting device corresponds to the thermistor9(the temperature-measuring device), and the value measured by the thermistor9corresponds to the parameter regarding the environmental conditions. Furthermore, the thermistor9according to the present embodiment is provided on the downstream side of the heater8(specifically, a position on the downstream side of and near the heater8), so that changes in the temperature (the rise of the temperature) of the liquid heated by the heater8can be detected immediately.

The estimating device11is a microcomputer or the like provided in the dialysis-apparatus body H and is configured to estimate the hot-water-disinfection time required for the hot-water disinfection of the tube in accordance with the value measured by the thermistor9(the parameter regarding the environmental conditions). Specifically, as summarized inFIG. 4, the estimating device11according to the present embodiment has a table for obtaining the hot-water-disinfection time from the value measured by the thermistor9. The table is prepared in accordance with the correlation, under certain environmental conditions, between the value measured by the thermistor9(the temperature-measuring device) and the temperature at a position of the circulation flow route that is on the downstream side of the thermistor9and on the upstream side of the heater8(the heating device), or preferably a position of the circulation flow route that is on the downstream side of the thermistor9and on the upstream side of and near the heater8(the heating device), or more preferably a position of the circulation flow route where the rise of the temperature with the heating by the heater8(the heating device) is slow, or particularly preferably a position of the circulation flow route where the rise of the temperature with the heating by the heater8(the heating device) is slowest.

The above table is obtained from an experiment or the like conducted in advance with the blood purification apparatus to be used. In the experiment, the environmental conditions, which are the power-source voltage (the input voltage of the heater8); the supply water temperature; and the ambient temperature, are each changed to any value between the upper limit and the lower limit, and the temperature (the time elapsed before the temperature rises to a predetermined temperature X° C., the degree of temperature rise in X minutes, or the like) is measured by the thermistor9under each of different sets of environmental conditions. Meanwhile, the following correlation is acquired in advance through an experiment or the like: the correlation, under each of the different sets of environmental conditions, between the value measured by the thermistor9(the time elapsed before the temperature rises to a predetermined temperature X° C., the degree of temperature rise in X minutes, or the like) and the temperature at a position of the circulation flow route that is on the downstream side of the thermistor9and on the upstream side of the heater8, or preferably a position of the circulation flow route that is on the downstream side of the thermistor9and on the upstream side of and near the heater8, or more preferably a position of the tube forming the circulation flow route where the rise of the temperature is slow (hereinafter, this position (referred to as the estimation position) is taken as a representative example, and examples of the estimation position that can be assumed include a position on the upstream side of and near the heater8, a position of the bypass line L5forming the circulation flow route, and a position of a line branching off from the dialysate introduction line L1or the dialysate drain line L2), or particularly preferably a position of the tube forming the circulation flow route where the rise of the temperature is slowest.

Thus, the relationship between the rise of the temperature measured by the thermistor9and the time period with which the required disinfection effect is guaranteed at the estimation position can be obtained, and the washing-disinfection time (the hot-water-disinfection time) can be obtained therefrom. The table created from the values measured by the thermistor9under the respective sets of conditions as described above (changes in the temperature) and the values of the washing-disinfection time (the hot-water-disinfection time) corresponding thereto is stored in the estimating device11. Thus, at the time of the hot-water-disinfection process, the hot-water-disinfection time required for the hot-water disinfection under the set of environmental conditions at that time can be estimated from the value measured by the thermistor9.

The hot-water-disinfection time estimated as described above is displayed, as illustrated inFIG. 5, on the monitor screen M included in the blood purification apparatus and is notified to a medical staff therearound. Specifically, the monitor screen M displays various pieces of information required, including a display part M1in which the sum of the hot-water-disinfection time and the required washing time (the time period for washing with washing water) is displayed, a display part M2in which the hot-water-disinfection time and the required washing time are displayed, and a remaining time M3before the completion of the hot-water disinfection. According to the present embodiment, the calculating device12is capable of calculating the completion time of hot-water disinfection (the point of time after the elapse of the hot-water-disinfection time from the present time) from the hot-water-disinfection time estimated by the estimating device11. Therefore, the completion time may also be displayed on the monitor screen M.

The present embodiment concerns a case where a parameter regarding environmental conditions is detected by the thermistor9(the temperature-measuring device). Alternatively, another detecting device that is capable of directly detecting environmental conditions (such as the input voltage of the heater8, the supply water temperature, and the ambient temperature) or yet another detecting device that is capable of detecting another parameter regarding such environmental conditions may be employed. Moreover, instead of or in addition to the input voltage of the heater8, the supply water temperature, and the ambient temperature, other conditions may be detected.

The above embodiment employs the detecting device (the thermistor9) that is capable of detecting environmental conditions at the time of the hot-water-disinfection process in which a tube is disinfected with hot water or a parameter regarding the environmental conditions, and the estimating device11that estimates the hot-water-disinfection time required for the hot-water disinfection of the tube (the optimum hot-water-disinfection time that guarantees the disinfection effect) from the environmental conditions or the parameter regarding the environmental conditions detected by the detecting device. Therefore, the hot-water-disinfection time can be optimized with consideration for the environmental conditions. The above embodiment further employs the calculating device12that calculates the completion time of the hot-water disinfection or the remaining time before the completion of the hot-water disinfection from the hot-water-disinfection time estimated by the estimating device11. Therefore, if the apparatus is configured to display the result of this calculation, the operator can recognize the completion time of the hot-water-disinfection process.

The above embodiment further employs the circulation tube for forming the circulation flow route that allows liquid to circulate in the hot-water-disinfection process, the heater8(the heating device) capable of heating the liquid that circulates through the circulation flow route and generating hot water that is at a temperature required for hot-water disinfection, and the thermistor9(the temperature-measuring device) capable of measuring the temperature of the liquid heated by the heater8. The detecting device corresponds to the thermistor9(the temperature-measuring device). The value measured by the thermistor9is taken as a parameter regarding the environmental conditions. Therefore, the required hot-water-disinfection time can be estimated by using the thermistor9that is intended for measuring the temperature of the tube during the blood purification treatment. Note that the required hot-water-disinfection time can be estimated by using the heater8(the heating device) and the thermistor9(the temperature-measuring device) because the heater8and the thermistor9are provided to the circulation flow route.

The estimating device11according to the present embodiment has the table for obtaining the hot-water-disinfection time from the value measured by the thermistor9, and the table is prepared in accordance with the correlation, under certain environmental conditions, between the value measured by the temperature-measuring device and the temperature at the position of the circulation flow route where the rise of the temperature with the heating by the heater8(the heating device) is slowest. Therefore, the required hot-water-disinfection time can be estimated more precisely and more smoothly. In particular, the thermistor9(the temperature-measuring device) according to the present embodiment is provided on the downstream side of the heater8(the heating device) (particularly, on the downstream side of and near the heater8). That is, the thermistor9is provided at a position where the rise of the temperature with the heating by the heater8is quick. Hence, the required hot-water-disinfection time can be estimated more quickly.

At least one of the sets of environmental conditions summarized in the table stored in the estimating device11may be identified from the value measured by the thermistor9(the temperature-measuring device). For example, as illustrated inFIG. 6, if the thermistor9is provided at a position of the dialysate introduction line L1that is on the upstream side of and near the heater8, the supply water temperature among the environmental conditions can be identified. Alternatively, as illustrated inFIG. 7, if the thermistor9(the temperature-measuring device) is provided at each of a position on the upstream side of and near the heater8and a position on the downstream side of and near the heater8, the input voltage of the heater8and the supply water temperature among the environmental conditions can be estimated and identified. Alternatively, as illustrated inFIG. 8, if the thermistor9is provided at each of a position of the dialysate introduction line L1that is near the distal end thereof and a position of the dialysate drain line L2that is near the distal end thereof (on the side where the connecting tools C1and C2are connected to each other), the ambient temperature among the environmental conditions can be identified. As described above, if at least one of the environmental conditions summarized in the table can be identified from the value measured by the thermistor9(the temperature-measuring device), the estimation can be made without the consideration for the other environmental conditions summarized in the table (the estimation can be made from the identified environmental condition). Therefore, the required hot-water-disinfection time can be estimated more precisely and more quickly.

While blood purification apparatuses according to some embodiments has been described above, the present teachings is not limited thereto. The thermistor9serving as the temperature-measuring device may be provided at any other position of the circulation flow route. For example, as illustrated inFIG. 9, the thermistor9may be provided to the bypass line L5(the circulation tube), and the hot-water-disinfection time required for the hot-water disinfection of the tube may be estimated by the estimating device11from the value measured by the thermistor9.

Alternatively, as illustrated inFIG. 10, a voltmeter13capable of directly measuring the input voltage of the heater8may be employed. In such a case, the value measured by the voltmeter13may be detected as one of the environmental conditions, and the hot-water-disinfection time required for the hot-water disinfection of the tube may be estimated by the estimating device11from the measured value. Moreover, another parameter (such as changes in the input control value (the operating ratio) of the heater8or the like) instead of the temperature measured by the thermistor9(the temperature-measuring device) or the voltage measured by the voltmeter13may be taken as a parameter regarding the environmental conditions. Specifically, the pressure of the liquid flowing in the tube, or any other parameter may be taken.

Instead of the blood purification apparatus included in a central system as described in the above embodiment, a personal dialysis apparatus (an apparatus capable of performing dialysis treatment with a dialysate at a predetermined concentration that is prepared by mixing undiluted dialysate and clean water together in a dialysis-apparatus body) is also acceptable. On the other hand, the timing with which the estimating device11estimates the hot-water-disinfection time required for hot-water disinfection is not limited to a point at the time of the hot-water-disinfection process. The estimation may be performed at the time of, for example, a dialysate-washing process (a washing process) performed before the hot-water-disinfection process, or at the time of a process of self-diagnosis of the tube (that is, the hot-water-disinfection time may be estimated before the hot-water-disinfection process is started). Moreover, the parameter, such as the temperature, used by the estimating device11may also be used for the diagnosis of any abnormality of the tube, any malfunction of the heater8, or the like.

The blood purification apparatus may have any additional functions, as long as the apparatus includes a detecting device that is capable of detecting environmental conditions at the time of the hot-water-disinfection process in which a tube is disinfected with hot water, or a parameter regarding the environmental conditions, and an estimating device that estimates the hot-water-disinfection time required for the hot-water-disinfection of a tube in accordance with the environmental conditions or the parameter regarding the environmental conditions detected by the detecting device.

REFERENCE SIGN LIST