JPH04200560A - Method and device for controlling ultrafiltration rate - Google Patents

Abstract

PURPOSE:To prevent a reverse ultrafiltration phenomenon and to improve the accuracy of an ultrafiltration rate measurement by first opening and closing a waste liquid shut off valve by a valve opening/closing control means prior to the measurement of the ultrafiltration rate, then closing the dialyzate shut off valve after lapse of a prescribed period of time. CONSTITUTION:Whether the ultrafiltration by a stationary mode elapses for the prescribed period of time or not is judged, and the ultrafiltration in the stationary mode is continued by returning when the set time is not attained. The mode is shifted to a measuring mode when the set time is attained. A controller 4 closes a waste liquid shut off valve 3, closes the port (b) of a three- way solenoid valve 19 and opens (a), (c). The flow passage from a dialyzate supply device 2 to a measuring cylinder 20 is formed via a dialyzer 1 in this way. The count values of a timer register TR are successively read with the time T0 as origin. Whether the preset required value is attained or not, i.e., whether the required time elapses or not, is judged. The command signal to close the dialyzate shut off valve 5 is sent to the controller 4 to close this valve upon lapse of the required time DELTAT from the time T0.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to, for example, an artificial dialysis method for blood, etc., and an apparatus therefor, and in particular, an ultrafiltration method that measures and controls the amount of ultrafiltrate. The present invention relates to a quantity control method and apparatus.

[Prior art] In artificial dialysis, it is necessary to control the amount of ultrafiltration depending on the case, and for this purpose, a transmembrane pressure difference is generated between the blood flow path and the dialysate flow path of the dialyzer. The ultrafiltrate is led out from the blood flow path to the dialysate flow path via the dialysis membrane, and the amount of ultrafiltration is measured from the increase in volume on the dialysate flow path side.

For example, Japanese Patent Publication No. 56-33965 discloses that while dialysate is constantly recirculated through a dialysate tank using a negative pressure pump, the amount of ultrafiltrate overflowing from the dialysate tank is measured, and a predetermined amount of ultrafiltrate is measured. The negative pressure valve installed upstream of the dialyzer is automatically U! A method and apparatus are disclosed in Section 4.

In addition, JP-A No. 52-94700 discloses that normally the dialysate is not allowed to flow, but the negative pressure is controlled, the flow of the dialysate is stopped periodically, and the amount of ultrafiltrate that oozes out is measured. A device is disclosed.

Furthermore, in JP-A No. 63-234973, the transmembrane pressure difference is normally controlled while the dialysate is flowing, and the circuit is periodically switched to a closed circulation circuit under the control of the transmembrane pressure difference. An apparatus is disclosed for determining the amount of ultrafiltrate from the weight increase of a metering bag connected to a metering bag.

[Problem to be Solved by the Invention 1] However, the above-mentioned conventional example has the following problems.

(1) That is, with any of the conventional methods and devices described above, it is possible to measure the amount of ultrafiltrate transferred from the blood side to the dialysate side, but for the reasons described below, in the unlikely event that
There is a problem in that even if a reverse ultrafiltration phenomenon (a phenomenon in which the filtrate moves from the dialysate side to the blood side) occurs, it cannot be determined.

For example, in the device disclosed in Japanese Patent Publication No. 56-33965, even if a reverse ultrafiltration phenomenon occurs, there is no overflow of dialysate from the dialysate tank, and the amount of ultrafiltrate is zero. , it is difficult to distinguish this from the situation where reverse ultrafiltration occurs.However, reverse ultrafiltration is a situation in which dialysate, which may be contaminated with bacteria, flows back into the human body, and should be avoided as much as possible. This is an inevitable phenomenon.

Recently, dialysis membranes with large pore sizes have been increasingly used to remove low-protein uremic toxin components with large molecular weights.

This membrane has high ultrafiltration performance, and the amount of ultrafiltrate changes significantly with a slight change in the transmembrane pressure difference (pressure difference between the blood side and the dialysate side). Therefore, when the amount of ultrafiltration to be controlled is small (therefore, when the transmembrane pressure difference is small), a reverse ultrafiltration phenomenon may occur due to temporal fluctuations in the transmembrane pressure difference.

(2) Furthermore, in the device described in Japanese Patent Application Laid-Open No. 63-234973, since no fluid flows through the flow path from the closed circulation circuit to the measuring bag during normal dialysis, this flow path is filled with liquid. Dissolved oxygen in the waste dialysate may become apparent and adhere to the inside of the flow pipe. Therefore, at the stage of measuring the amount of ultrafiltrate, when waste dialysate equivalent to the amount of ultrafiltrate flows through the flow path, air bubbles attached to the flow path and The waste dialysate is replaced, and the amount of waste dialysate that enters the metering hang decreases accordingly. However, since the amount of ultrafiltration to be measured is extremely small, such as several mf, the presence of such bubbles also poses a problem in that the measurement accuracy of the amount of ultrafiltrate deteriorates.

The present invention has been made in view of the above circumstances, and provides an ultrafiltration system that can prevent the reverse ultrafiltration phenomenon and can accurately measure the amount of ultrafiltrate. The object of the present invention is to provide a quantity control method and apparatus.

[Means for Solving the Problems] In order to achieve the above object, the present invention employs the following ultrafiltration rate control method.

That is, a dialysate supply channel having a dialysate cutoff valve and a waste dialysate discharge channel having a wastewater cutoff valve are connected to the dialyzer, and both valves are intermittently controlled by a valve opening/closing control means, The dialysate supply flow path and the waste dialysate discharge flow path are switched to an open circuit or a closed circuit, and then the transmembrane pressure difference between the blood side flow path and the dialysate side flow path reaches a preset transmembrane pressure difference. While controlling the negative pressure pump so as to match the amount of ultrafiltrate drawn out from the blood flow path to the dialysate side flow path, the amount of ultrafiltrate is guided to a waste dialysate reservoir provided in the waste dialysate discharge path. In the method for controlling the amount of ultrafiltration in which the amount of ultrafiltration is measured, prior to measuring the amount of ultrafiltration, first, the waste liquid cutoff valve is closed by a valve opening/closing control means, and then, the dialysate cutoff valve is closed after a predetermined period of time has elapsed. It is characterized by

Furthermore, the apparatus of the present invention for achieving the above object has the following configuration.

That is, a dialyzer includes a blood flow path, a dialysate flow path, and a dialysis membrane that distinguishes between these two flow paths and leads out the ultrafiltrate from the blood flow path to the dialysate flow path; a dialysate cutoff valve provided in the dialysate supply flow path of the dialyzer to open and close the flow path; and a negative pressure pump that generates a transmembrane pressure difference between the blood flow path and the dialysate flow path of the dialyzer. and a waste liquid cutoff valve that is installed in the waste dialysate discharge flow path from the dialyzer to open and close this flow path, and two chambers separated by a movable diaphragm, one chamber containing the dialysate. an equalization device that is connected in communication with a dialysate supply flow path between the cutoff valve and the dialyzer, and the other chamber is connected in communication with a waste dialysate discharge flow path between the drain cutoff valve and the negative pressure pump; , connected to the waste dialysate discharge flow path between the connection part of the equalization device and the waste liquid cutoff valve, and pumping waste dialysate corresponding to the amount of the ultrafiltrate that has flowed in through the communication path. In an ultrafiltration rate control device comprising: a waste dialysate reservoir for storing; and a liquid amount detection means for detecting the amount of liquid in the waste dialysate reservoir; Based on a valve opening/closing control means that closes the waste liquid cutoff valve and then closes the dialysate cutoff valve after a predetermined period of time has elapsed, and a detection signal from the fluid volume detection means after the dialysate cutoff valve is closed, A fluid volume change detection means for determining whether the waste dialysate in the waste dialysate reservoir is increasing or decreasing; and the fluid volume change detection means determines whether the waste dialysate in the waste dialysate reservoir is increasing or decreasing. If detected, an ultrafiltrate amount calculating means calculates an ultrafiltrate amount based on a detection signal from the fluid amount detecting means, and the fluid amount change detecting means detects waste in the waste dialysate storage device. The present invention is characterized by comprising a reverse ultrafiltration eliminating means that takes predetermined reverse ultrafiltration eliminating measures when a decrease in dialysate is detected.

Furthermore, in the above-described limit 74 overflow control device, a connection is provided to connect the dialysate cutoff valve and the waste liquid cutoff valve to each other in place of the equalization device that is communicatively connected to the waste dialysate discharge path. A flow path is provided, and by intermittently switching between the dialysate cut-off valve and the waste liquid cut-off valve by the valve opening/closing control means, the dialysate is supplied from the dialysate through the dialyzer and the waste dialysate discharge flow path. A closed circuit is formed leading to the connection circuit, and the closed circuit is switched O. At this time, the valve opening/closing control means first closes the waste liquid cutoff valve, and then, after a predetermined period of time, the dialysate is turned off. The feature is that the shutoff valve is closed.

[Operation] According to the method and device of the present invention, the valve opening/closing control means closes the dialysate cutoff valve with a slight delay from the closure of the waste liquid cutoff valve during the ultrafiltration rate measurement mode. The dialysate supplied within the time interval flows through the dialyzer and into the waste dialysate reservoir.

Therefore, the air bubbles attached to the inner wall of the waste dialysate outlet are pushed out together with the inflow liquid into the waste dialysate reservoir, and in the subsequent ultrafiltration measurement mode, the air bubbles are replaced with waste. Errors caused by decrease in dialysate are eliminated.

Further, according to the device of the present invention, before measuring the waste dialysate, the inflow liquid is stored in the waste dialysate reservoir, so that during actual measurement, the increase or decrease of the waste dialysate is It is detected by the amount change detection means. In other words, it is detected whether normal ultrafiltration is being performed or whether inverse specific ultrafiltration is occurring.

If inverse specific extrafiltration occurs, improvement measures using inverse specific extrafiltration eliminating means are promptly taken.

[Embodiment 7] Hereinafter, embodiments of the method and apparatus of the present invention will be described based on the drawings.

Figure 1 shows flow sorting of the apparatus according to the first embodiment of the present invention.

In the figure, the dialyzer with reference numeral 1 is divided into two units via a dialysis membrane (not shown), one chamber is connected to the blood side flow path A, and the other chamber is supplied with dialysate. A dialysate supply channel B from the device 2 to the inlet port (not shown) of this dialyzer 1 and a waste liquid isolation valve 3 from the outlet port (not shown) of the dialyzer 1.
A waste dialysate discharge channel C leading to is connected.

The dialysate supply channel B is connected to the equipment described below.

That is, the dialysate supply device 2 mixes and prepares fresh dialysate in advance, and the dialysate cutoff valve 5 is opened and closed by control signals from the controller 4.

This controller 4 and a microprocessor 17 to be described later
corresponds to the valve opening/closing control means, and the microprocessor 17
also corresponds to an ultrafiltration liquid amount calculation means and an inverse ultrafiltration phenomenon elimination means.

Reference numeral 6 denotes a constant pressure valve that prevents fluctuations in supply pressure from the dialysate supply device 2 from directly affecting the dialyzer 1 and keeps the pressure constant. The type of constant pressure valve 6 is a self-cutting pressure valve that operates based on a preset pressure using the pipe pressure in the dialysate supply flow path B as a pilot pressure, preferably a self-cutting pressure valve that operates based on a preset pressure, preferably a control device (not shown). An automatic pressure regulating valve that opens and closes under control is used.

7 is a heater that raises the temperature of the fresh dialysate to the human body temperature and maintains it; 8 is a boost pump that further increases the pressure in order to stably supply the fresh dialysate coming out of the constant pressure valve 6; its model is, for example,
Volute pump, gear pump.

etc. are used.

Reference numeral 9 denotes a measuring tank corresponding to an equalization device, which is divided into two parts by an elastic membrane 10 into a right ventricle that temporarily stores fresh dialysate and a left ventricle that temporarily stores waste dialysate. ing. Furthermore, a branch pipe H that communicates with the dialysate supply channel B between the heater 7 and the boost pump 8 is connected to the right chamber of this metering tank 9, and a waste dialysate discharge channel described later is connected to the left chamber. C
A branch pipe E that communicates with the gas-liquid separation tank 18 is connected.

1] is a constant flow valve to keep the flow rate of fresh dialysate constant, and the rate of supply of dialysate to the dialyzer 1 (Il is usually 500+II]/m1n) regardless of the pressure change of the boost pump 8.
is controlled at a constant level. Generally, those having the same structure as mechanical self-blade flow valves used in the industrial field are used. In addition, the reference numeral 12 is a flow switch that displays the flow rate of fresh dialysate and issues an alarm when the upper or lower limit of the prescribed liquid volume is exceeded, and 13 is a flow meter.

The waste dialysate discharge flow path C is a flow path for discharging waste dialysate out of the system, and the equipment described below is connected within this flow path C.

That is, 14 is a negative pressure pump that generates negative pressure in the waste dialysate discharge channel C in order to generate a specified transmembrane pressure in the dialyzer 1, and 15 is a dialysate pressure sensor that detects this negative pressure. .

17 outputs a control signal to the negative pressure pump 14 in order to keep the difference in pressure detected by the blood pressure sensor 16 and the dialysate pressure sensor 15 (hereinafter referred to as transmembrane pressure difference) constant;
It is a microprocessor that gives the controller 4 the timing to switch answers and calculates the amount of water removed by ultrafiltration. The second microprocessor 17 is connected to a timer register TR that counts up every certain period of time (for example, 10 ims!) and a RAM that stores calculated water removal amount data.

The dialysate pressure sensor 15 may be provided in either one or both of the dialysate supply flow path B and waste dialysate discharge flow path C depending on the required dialysate pressure detection accuracy.

] 8 is a gas-liquid separation tank for separating gas mixed in the waste dialysate, and has a vertically long cylindrical shape, with the waste dialysate discharge channel C from the negative pressure pump 14 running from the side to the top. A waste dialysate discharge channel C is connected to the waste liquid cutoff valve 3 from the bottom, and a branch pipe E communicating with the measuring tank 9 is connected from the bottom.

19 is a three-way solenoid valve provided in the bypass path I of the waste liquid cutoff valve 3; boats (B) and (B) are connected to the bypass path I, and the boat (A) is connected to the measuring cylinder 20.

The measuring cylinder 20 corresponds to a waste dialysate reservoir according to the present invention,
The upper part is opened to the atmosphere and the gas contained in the dialysate is released to the outside. It is suspended on a hook 21 attached to the lower part of a load cell 22 serving as a quantity detection means.

The load cell 22 is fixed at a constant height and measures the weight of water removed with a high precision of resolution of 0.1 [gl] due to the ultrafiltration action stored in the measuring cylinder 20. The value is output to the weight controller 23 and via this to the microprocessor 17.

The weight controller 23 displays the weight detected by the load cell 22, and issues an alarm if the weight exceeds a specified weight.

Next, the operation of the above-described device will be explained.

This device operates in a preparation mode, which is a preparatory step before transitioning to the steady mode, which is normal ultrafiltration operation, in a steady mode, which performs ultrafiltration on a regular basis, and in which the amount of ultrafiltration is measured at each set time. Weighing modes are classified into 03 modes.

First, in the preparation mode, dialysate cutoff valve 5. The waste liquid cutoff valves 3 are both set to the open state, and fresh dialysate is delivered from the dialysate supply device 2. At this time, the boat of the three-way solenoid valve 19 (
A) and (B) are set to open, and (c) is set to closed.

Fresh dialysate from the dialysate supply device 2 is adjusted to a constant liquid supply pressure by a constant pressure valve 6, heated to the human body temperature by a heater 7, and then flows into a boost pump 8 and a metering tank 9. Measuring tank 9
The flow continues until the elastic membrane [0] comes into close contact with the left wall.

The fresh dialysate pressurized by the boost pump 8 then has its inflow rate adjusted by a constant flow valve 11, and flows into the dialyzer 1 via a flow switch 12 and a flow meter 13.

Since the waste dialysate discharge channel C is maintained at a specified transmembrane differential pressure by the negative pressure pump 14, an ultrafiltration effect occurs in the dialyzer 1, and the dialysate is removed from the blood side channel A. A quantity of water is added and both are discharged to the waste dialysate discharge channel C.

Dialyzer 1. The waste dialysate that has passed through the negative pressure pump 14 passes through a gas-liquid separation tank 18, passes through a waste liquid cutoff valve 3, and is discharged to the outside of the system.

The next step is steady mode (during this mode, the stone chamber of the metering tank 9 is filled with fresh dialysate.

) is a mode in which the limit a period in the preparation mode is constantly continued.

The operations in the preparation mode and steady mode described above are similar to those of the apparatus introduced in the conventional example.

Next, we will discuss the operation of this device in the weighing mode in the second section.
This will be explained with reference to the processing flow diagram of the microprocessor 17 shown in the figure.

First, in step Sl, it is determined whether the ultrafiltration in the steady mode has elapsed for a set time.

This judgment is made by reading the contents of timer register TR,
The count value and the set value (timer according to the set time)
This is done by comparing the count value of register TR.

If the set time has not yet been reached, the process returns to continue ultrafiltration in the steady mode, and when the set time has been reached, the process proceeds to the following steps and shifts to the metering mode.

In step S2, the waste liquid cutoff valve 3 is connected to the controller 4.
Then, in step S3, a command signal is sent to switch the three-way solenoid valve 19 to the metered cylinder 20 side.

The controller 4 closes the waste liquid cutoff valve 3, and
Close port (b) of three-way solenoid valve 19, (a).

(c) Open. Thereby, a flow path is formed from the dialysate supply device 2 to the measuring tube 20 via the dialyzer 1. Let the time at this point be To.

In step S4, the count value of the timer register TR is sequentially read with time T0 as the origin, and it is determined whether the count value has reached a preset required value, that is, whether the required time has elapsed.

For example, if the required time is 2001m5l, 1
011IlsiThis is the timer that counts up.
Since it is a register TR, the elapse of the required time is determined based on whether the count value has reached "20". Let this required time be ΔT.

After the required time ΔT has elapsed from time T0, the process proceeds to step S5, where a command signal is sent to the controller 4 to close the dialysate cutoff valve 5, thereby causing it to close.

In the device of this embodiment, the control order of the dialysate cutoff valve 5, the magnetic valve 19 on three sides (between ports (A) and (C) on the dialyzer 1 side), and the waste dialysis cutoff valve 3 is dialysis-i cutoff. The sequence is valve 5 → three-way solenoid valve 19 → waste liquid cutoff valve 3, but the point is that the ultrafiltrate only needs to flow into the measuring tube 20 before officially measuring the amount of ultrafiltration.

Therefore, although individual process flow diagrams are omitted, the opening/closing order of the answer 5.19.3 explained in steps 82 to S5 may be the valve opening/closing order patterns A to D shown in the following table.

(Hereinafter, blank space) In other words, the numbers shown in the table indicate the opening/closing order of the three valves mentioned above.For example, the opening/closing pattern in the column of "Present Example" in the table is as described above. Waste liquid cutoff valve 3 closed,
Mikata T! L solenoid valve 19 (ports (a) and (b) open → (
It shows that the dialysate cutoff valve 5 is switched in the order of ``open'' and ``closed'' between a) and (c).

In addition, the opening/closing patterns C and D are - temporally negative pressure pump 14
At first glance, this may seem inconvenient because the discharge side of the dialysate is completely closed and there is no supply of waste dialysate to the measuring cylinder 20. However, during this time, the discharge pressure of the negative pressure pump 14 rises slightly, and the waste dialysate discharge channel C, which is usually made of a nylon tube,
Expansion of the dialysate causes waste dialysate to accumulate in this flow path. Since this accumulated amount flows into the measuring cylinder 20 at the moment the three-way solenoid valve 19 is switched to the measuring mode, there is no practical problem, and the effects of the present invention can also be achieved in this pattern. .

Any of these opening/closing patterns can feed the waste dialysate into the measuring tube 20 before formal measurement as described above, so any opening/closing pattern can provide the effects of the present invention, which will be described later. can.

In this way, after the waste liquid cutoff valve 3 is closed and the flow path to the measuring tube 20 is opened (time To), the dialysate cutoff valve 5 is closed after the required time (eight T) has elapsed. Waste dialysate, which is the dialysate discharged from the dialysate supply device 2 within the required time (ΔT), flows into the tube 20 . Eight T is especially
Although not limited, usually 5 to 200m5, preferably 50m5
It is 0m5~10100O. Further, the amount of flow into the measuring cylinder 20 is about 2 to 10 ml. When this phenomenon is expressed as a change in the weight of the measuring tube 20 over time, it becomes as shown in the graph of FIG.

That is, time T. Until then, only the dead weight W0 of the measuring barrel 20 was measured by the load cell 22, and there was no change in weight. However, from time T0 to time T0+ΔT=T', due to the delay in closing the dialysate cutoff valve 5, the measuring barrel 20 As the liquid flows in, the weight increases rapidly, and by time T', W0+Δw=w
'To increase. Note that the setting of the time from when the waste fluid cutoff valve 3 is closed until the dialysate cutoff valve 5 is closed is not a direct time setting, but a fixed amount (ΔW) increase from the state in which the waste dialysate storage tank is in steady mode. The dialysate cutoff valve 5 may be closed after detecting that this has occurred. In short, it is only necessary to set a delay in the opening/closing operation time of the waste liquid cutoff valve 3 and the dialysate cutoff valve 5.

Due to the inflow of waste dialysate corresponding to this weight increase (ΔW), air bubbles adhering to the flow path leading to the measuring cylinder 20 are pushed out into the measuring cylinder 20. Therefore, the decrease in the amount of ultrafiltration due to the replacement of "air bubbles" with the "ultrafiltrate", which was raised as a problem with the conventional example, does not occur, and from now on, the measuring cylinder 2
The amount of ultrafiltrate flowing into 0 is to be accurate.

Furthermore, since the required amount of waste dialysate is stored in the measuring tube 20 before measuring the amount of ultrafiltrate, it is possible to detect not only an increase in the amount of ultrafiltrate but also a decrease. The occurrence of the inverse extrafiltration phenomenon can be determined by the method described below.

In step S5, when the dialysate cutoff valve 5 is closed, the flow of the entire amount of waste dialysate into the measuring tube 20 is stopped as described above, and the supply of fresh dialysate is cut off. 14 is applied to the waste dialysate discharge channel C, the fresh dialysate temporarily stored in the right chamber of the metering tank 9 is pressurized by the boost pump 8,
The ultrafiltration is performed while being supplied to the dialyzer 1 through the branch pipe H and the dialysate supply channel B, and the same amount of waste dialysate flows into the measuring tube 20.

In step S6, the preset first survey time T1
determine whether it has become. The amount of ultrafiltration is detected from the weight increase of the measuring tube 20 between this first measuring time T and a second measuring time T2, which will be described later. The time T' (
It is set at a slight time interval α from the time of transition from steady mode to metering mode.

This is to prevent the amount of ultrafiltration during the pressure fluctuation of the negative pressure pump 14 that occurs when switching from steady mode to metering mode from being captured as measurement data, and after a few seconds, the negative pressure pump 14 returns to the specified pressure. Return.

To judge the progress of the first survey time T, the origin is the time T', and the contents of the timer register TR are (T + =
The judgment may be made at the time T' 10a), or at the time T. is the origin, and the contents of the timer and counter are (
The determination may be made at the time when T,=T,+ΔT+α) (see FIG. 3).

In step S7, the weight output value W of the load cell 22 (weight value of the measuring tube 20) at the first measurement time T is read.

In step S8, the contents of the timer register TR are read again, and when the preset second survey time T2 is reached, the process proceeds to the next step S9.

In step S9, the weight output 4fIWx (weight value of the measuring tube 20) of the load cell 22 at the second measurement time T2
Load.

Note that when reading the weight output values W, W2 in steps S7 and 89, the weight output values are continuously loaded into the FA multiple times (for example, 7 times), and the average of these is calculated as the respective weight output value w. ,,w2' may be used.

In step S10, Wl and W2 are compared and "Wl
Determine whether ≦w2 J.

If W is a value less than W2 (if the weight of the measuring cylinder 20 has increased), it is assumed that water is being removed from the blood by ultrafiltration, and the process proceeds to step Sll, where the following formula (■) is used. Therefore, calculate the amount of water removed per unit time and set it as R
Store in AM.

(Hereafter, blank space) T2 T1 However, if Wl is a larger value than W2, then (
If the weight of the measuring cylinder 20 has decreased), it is assumed that the dialysate is flowing back into the blood due to the inverse extrafiltration phenomenon, and the process proceeds to step S12, where an alarm is issued. For example, it may sound an alarm or turn on a patrol light to alert a doctor.

Following this, in step S13, the supply of dialysate is stopped, and ultrafiltration is forcibly interrupted.

Alternatively, proceed to step TI2 as shown in the fourth diagram,
The amount of inverse extrafiltration phenomenon is calculated by the following formula, 2-T1.Next, in step T13, the rotation speed of the negative pressure pump 14 is controlled according to the calculated amount of inverse extrafiltration phenomenon, and the transmembrane differential pressure is adjusted. Correct the situation and return to normal ultrafiltration.

In addition, a judgment standard is set for the degree of inverse ultrafiltration, and if it is (+) larger than the standard value, ultrafiltration is forcibly interrupted and an alarm is sounded.

(2) If it is medium, the transmembrane differential pressure value is corrected to a value with a slight margin from the formula obtained in (1) above, and an alarm is sounded.

(3) If the difference is slight, the transmembrane differential pressure may be corrected based on the formula obtained in (2) above.

The inverse specific extrafiltration phenomenon is caused by the transmembrane differential pressure (symbol 1 in FIG.
If the pressure fluctuation of the negative pressure pump 14 occurs when the differential pressure between the blood pressure detected by sensor 6 and the dialysate pressure detected by sensor 15 is small, the blood pressure is higher than the dialysate pressure. This is when the dialysate becomes larger and the dialysate flows back into the blood.

Therefore, to return this to normal ultrafiltration,
The pressure of the negative pressure pump 14 is increased, and the transmembrane pressure is corrected so that even with slight pressure fluctuations, the blood pressure does not become dialysate pressure and water in the blood can be removed.

After the transmembrane pressure difference is corrected, or after it is determined in step Sll that normal ultrafiltration is being performed and the amount of water removed is calculated, in step S14, the controller 4 sets the waste liquid cutoff valve 3.
and output a command signal to open the dialysate cutoff valve 5,
Next, in step S15, a command signal to switch the three-way solenoid valve 19 to the drain side is output. Note that in this case, step S14 and step SI5 may be performed at the same time.

The controller 4 opens the waste liquid cutoff valve 3 and the dialysate cutoff valve 5 in response to these command signals, and also opens the three-way 1t+11
Close the boat (c) of valve 19 and open the port (b). As a result, the ultrafiltrate stored in the measuring tube 20 is discharged, and the ultrafiltration in the steady mode described above is restarted.

At this point, the timer register TR is reset (step 516), and the process returns to step Sl, and when the set time comes again, measurement of the ultrafiltration amount in the measurement mode is repeated as described above.

Figure 5 is a flow sheet of an apparatus according to a second embodiment of the present invention. This figure shows only the parts that are different from the first embodiment described above, and the configuration other than that shown in the figure is the same as that of the first embodiment shown in FIG.
The structure is similar to that of the embodiment.

That is, in the device of this example, instead of the measuring barrel 9, a measuring bank 30 is suspended and supported by the hook 21 of the load cell 22, and the three-way solenoid valve 19. It has a configuration in which the heater 7 and the gas-liquid separation tank 18 are eliminated.

The weighing bank 30 is a sealed bag made of a flexible elastic membrane made of, for example, silicone rubber or soft vinyl chloride resin, which expands freely when filled with liquid.

Furthermore, the metering bank 30 is communicated with the waste dialysate discharge channel C via a flexible tube 31 connected to its lower end.

The operation of the device of this second embodiment is similar to that of the first embodiment. That is, in the metering mode, after a small amount of waste dialysate is stored in the metering hack 30 by closing the waste liquid shut-off valve 3 and then closing the dialysate shut-off valve 5 with a slight time delay (△T). , detecting the weight change of the weighing hack 30,
This is intended to distinguish between ultrafiltration and inverse ratio extrafiltration.

In both of the above-described embodiments, the amount of ultrafiltration is measured based on the change in weight of the measuring tube 20 or the measuring hack 30, but it may also be measured based on the change in volume.

Figure 6 is a flow sheet of an apparatus according to a third embodiment of the present invention.

In this figure, the same reference numerals as in FIGS. 1 and 2 refer to the same members, so detailed explanation thereof will be omitted.

The difference between the device of this embodiment and the devices of the first and second embodiments is as follows.
■The metering tank 9 is omitted from the device of the first embodiment (■Instead, the dialysate cutoff valve 5a and the waste liquid cutoff valve 3a are each
A three-way electromagnetic valve having two boats a to C is used, and the two valves 5a and 3a are connected to each other by a connecting flow path.Other points are the same as the device of the first embodiment.

It goes without saying that the device of this third embodiment is also included in the present invention, and its effects will be explained below.

That is, (1) First, in both the preparation and steady mode, the dialysate cutoff valve 5
The controller 4 establishes communication between the two ports a and b of the waste liquid cutoff valve 3a and the waste liquid cutoff valve 3a (in this case, both the valves 5a
, 3a are both closed), fresh dialysate is supplied from the dialysate supply device 2 through the dialysate supply device 2 → dialysate cutoff valve 5a → dialysate supply channel B → dialyzer 1 → The dialysate is discharged to the outside of the apparatus as indicated by the arrow in the figure through a one-pass flow path consisting of waste dialysate discharge path C→negative pressure pump 14→boat a of waste fluid cutoff valve 3a.

(2) Next, the dialysate cutoff valve 5a and the waste liquid cutoff valve 3 are
When switching to the metering mode in which each boat a is closed and boats b and c are in communication, the dialysate flow path is as follows: dialysate cutoff valve 5a → dialysate supply flow path B → dialyzer 1
→ Waste dialysate discharge flow path C → Negative pressure pump 14 → Waste liquid cutoff valve 3
A closed circuit consisting of a→connection channel D→dialysate cutoff valve 5a is formed.

(3) In the device of this embodiment, when switching to the metering mode, boat a of the waste liquid cutoff valve 3a is first closed before the dialysate cutoff valve 5a, and at the same time boats b and c are placed in a communicating state. be made into

(4) Fresh dialysate is supplied from the dialysate supply device 2, and the waste dialysate in the waste dialysate discharge channel C, which has been turned into waste dialysate by the dialyzer 1, is closed by the boat c of the dialysate cutoff valve 5a. Since the dialysate has a place to go, it flows into the measuring bag 30 concentrically with the air bubbles attached to the inner wall of the waste dialysate discharge channel C.

(5) Next, after a time lag of about 0.5 to 200 a+s, boat a of the dialysate cutoff valve 5a is closed and boats b and c are brought into communication at the same time, and the volume in the closed circuit is constant. Therefore, waste dialysate in an amount equivalent to a predetermined ultrafiltrate discharged from the blood side flow path A to the waste dialysate discharge path C by the negative pressure pump 14 is stored in the measuring hang 30, and the amount is stored in the measuring hang 30, and the amount is stored in the measuring hang 30. Measured by controller 23 and microprocessor 17.

At this time, if an inverse filtration phenomenon occurs, measures to eliminate it are promptly taken in accordance with instructions from the microprocessor 17 and the controller 4.23 using the same procedure as described in the section of the first embodiment. .

[Effects of the Invention] As is clear from the above description, the method and device for controlling the amount of ultrafiltration of the present invention shuts off the dialysate with a slight delay from the closing of the waste liquid cutoff valve when measuring the amount of ultrafiltration. Since the valve is closed, the dialysate supplied within this time interval is
The waste dialysate flows into the waste dialysate reservoir via the waste dialysate discharge channel. As a result, air bubbles attached to the inner wall of the waste dialysate discharge channel can be pushed out together with the inflow fluid into the waste dialysate reservoir, and the accuracy can be minimized to minimize the loss of waste dialysate due to replacement with air bubbles. A good amount of ultrafiltrate can be detected.

Furthermore, in the ultrafiltration rate control device of the present invention, before measuring the amount of ultrafiltrate, the inflow liquid is stored in the waste dialysate reservoir in advance, so that the amount of ultrafiltrate can be detected. By detecting an increase or decrease in the amount of waste dialysate in the reservoir, it is possible to determine whether normal ultrafiltration or inverse ultrafiltration is occurring.

If inverse extrafiltration occurs, countermeasures can be taken immediately using inverse extrafiltration prevention means, thereby immediately eliminating the situation where waste dialysate is mixed into the blood circulating through the human body. be able to.

[Brief explanation of the drawing]

1 to 6 relate to an embodiment of the present invention, FIG. 1 is a flow sheet showing a schematic configuration of an ultrafiltration rate control device according to the first embodiment, and FIG. 2 is a flow sheet showing the processing of a microprocessor. A flowchart showing the procedure, Figure 3 shows the weight of the measuring cylinder.
A graph showing changes over time, FIG. 4 is a partial flowchart showing other processing steps of the microprocessor, FIG. It is a flow sheet showing the main parts of the device according to the example. 1... Dialyzer 3... Waste liquid cutoff valve 4... Controller 5... Dialysate cutoff valve 9... Measuring tank
10...Elastic membrane 14...Negative pressure pump 17...Microprocessor 19...Three sides 1 are connected to magnetic valve 20...Measuring cylinder 22...Load cell A...
・Blood flow path B...Dialysate supply flow path C...Waste dialysate discharge flow path Applicant: Azuma Shi Co., Ltd. Representative Patent Attorney Tsutomu Sugitani Figure 2-9-Ward C Plasticity. Figure 5C Figure 6

Claims (3)

[Claims] (1) A dialysate supply channel having a dialysate cutoff valve and a waste dialysate discharge channel having a wastewater cutoff valve are connected to the dialyzer, and both valves are intermittently controlled by a valve opening/closing control means. , the dialysate supply flow path and the waste dialysate discharge flow path are switched to an open circuit or a closed circuit, and then the transmembrane pressure difference between the blood side flow path and the dialysate side flow path is set to a preset transmembrane pressure difference. While controlling the negative pressure pump so as to correspond to In the method for controlling the amount of ultrafiltration in which the amount of ultrafiltration is measured, the waste liquid cutoff valve is first closed by a valve opening/closing control means, and then the dialysate cutoff valve is closed after a predetermined period of time has elapsed, prior to measuring the amount of ultrafiltration. An ultrafiltration rate control method characterized by: (2) A dialyzer comprising a blood flow path, a dialysate flow path, and a dialysis membrane that differentiates these flow paths and leads out the ultrafiltrate from the blood flow path to the dialysate flow path; and the dialyzer. a dialysate cutoff valve provided in a dialysate supply flow path to open and close this flow path; and a negative pressure pump that generates a transmembrane pressure difference between the blood flow path and the dialysate flow path of the dialyzer. a waste liquid cutoff valve that is installed in the waste dialysate discharge flow path from the dialyzer to open and close this flow path; and two chambers separated by a movable diaphragm, one of which contains the dialysate. an equalization device that is connected in communication with a dialysate supply flow path between the cutoff valve and the dialyzer, and the other chamber is connected in communication with a waste dialysate discharge flow path between the drain cutoff valve and the negative pressure pump; , connected to the waste dialysate discharge flow path between the connection part of the equalization device and the waste liquid cutoff valve, and pumping waste dialysate corresponding to the amount of the ultrafiltrate that has flowed in through the communication path. In an ultrafiltration rate control device comprising: a waste dialysate reservoir for storing; and a liquid amount detection means for detecting the amount of fluid in the waste dialysate reservoir; Valve opening/closing control means for closing the waste liquid cutoff valve and then closing the dialysate cutoff valve after a predetermined period of time has elapsed, based on a detection signal from the fluid volume detection means after the dialysate cutoff valve is closed, A fluid volume change detection means for determining whether the waste dialysate in the waste dialysate reservoir is increasing or decreasing; and the fluid volume change detection means determines whether the waste dialysate in the waste dialysate reservoir is increasing or decreasing. If detected, an ultrafiltrate amount calculating means calculates an ultrafiltrate amount based on a detection signal from the fluid amount detecting means, and the fluid amount change detecting means detects waste in the waste dialysate storage device. An ultrafiltration amount control device comprising: a reverse ultrafiltration eliminating means that takes predetermined reverse ultrafiltration eliminating measures when a decrease in dialysate is detected. (3) In the ultrafiltration rate control device according to claim (2), instead of the equalization device communicatingly connected to the waste dialysate discharge path, the dialysate cutoff valve and the waste liquid cutoff valve are connected to each other. A connection channel is provided to connect the dialysate to the dialyzer and the waste dialysate discharge channel from the dialysate supply channel by intermittently switching between the dialysate cutoff valve and the waste fluid cutoff valve by the valve opening/closing control means. A closed circuit is formed that connects to the connection circuit via An ultrafiltration rate control device characterized by closing a valve.