JPH069670Y2 - Water removal controller for hemodialysis machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION “Industrial field of application” The present invention relates to a hemodialysis apparatus used for treating a patient with renal failure, and more particularly to a water removal amount control device for controlling the water removal amount.

"Conventional technology" As a representative one of the current water removal control
There is an ECUM system. The ECUM method is performed as shown in FIG. That is, the blood from the patient 11 is supplied by
The blood thus supplied to the dialyzer 13 and from which water and wastes have been removed by the dialyzer 13 is returned to the patient 11 via the drip chamber 14. On the other hand, the dialysate is supplied from the liquid supply channel 15 to the dialyzer 13 via the first on-off valve 16, and the dialyzer 1
The dialysate from No. 3 is drained from the drainage channel 17 via the second opening / closing valve 18 and further by the negative pressure pump 19. The branch passage 21 is connected between the inlet of the first opening / closing valve 16 and the outlet of the second opening / closing valve 18, and the third opening / closing valve 22 is inserted in the branch passage 21.

In the measurement mode, the first opening / closing valve 16 and the second opening / closing valve 18 are closed, the third opening / closing valve 22 is opened, and the water removal amount measuring pump 23 provided between the dialyzer 13 and the second opening / closing valve 18
Is drawn, and the dialysate-side pressure Q of the dialyzer 13 when the predetermined amount of water is removed is measured by the pressure measuring device 24. A relationship between the difference P−Q (TMP: permeable membrane pressure) between the dialysate side pressure Q and the blood side pressure P and the amount of water removed can be obtained.

In the dialysis mode, the first opening / closing valve 16 and the second opening / closing valve 18 are opened, the third opening / closing valve 22 is closed, and the dialysate is caused to flow into the dialyzer 13, and the TMP at this time is controlled to be the measured TMP. To do.

In addition, there is a system in which two reciprocating metering pumps are provided to make the inflow and outflow dialysate amounts to the dialyzer equal, and forcibly remove the amount of liquid corresponding to the dewatering amount by the third dewatering pump.
A typical example of this system is shown in FIG. That is, the reciprocating metering pumps 25 and 26 are provided, and these are interlocked with each other. When the dialysate is being supplied from the metering chamber 25b of the reciprocating metering pump 25 to the dialyzer 13, the dialyser 13 supplies the dialysate to the metering pump 25. It is taken into the measuring chamber 25a, while the metering pump 2
The dialysate to be supplied to the measuring chamber 26a of No. 6 is taken in, and the dialysate taken in to the measuring chamber 26b is discharged. On the contrary, metering pump 2
When the dialysate in the measuring chamber 26a of No. 6 is supplied to the dialyzer 13,
The dialysate from the dialyzer 13 is taken into the measuring chamber 26b, the metering pump 25 takes in the dialysate to be supplied to the measuring chamber 25b, and the dialysate in the measuring chamber 25a is discharged.

The dialysate discharged from the dialyzer 13 is also drawn by the water removing pump 27, and the amount of dialysate drawn by the water removing pump 27 is the same as the amount supplied to the dialyzer 13 by the metering pump 25 or 26. The difference from the amount subtracted from 13.

By using the four measuring chambers in this manner, the problem of discontinuous flow of dialysate due to the reciprocating movement of the metering pump is solved.

“Problems to be solved by the device” In the conventional method shown in FIG. 4, the water removal amount is not measured except in the measurement mode, and the dialyzer is used when the dialysate is flowing and when it is stopped. The pressure inside 13 is different and causes an error. In recent dialysers, the amount of water removed per TMP is about 5 times that of conventional ones, and
A small TMP error, which has not been a problem in the past, causes a large water removal error and is a clinical problem.

On the other hand, the method shown in FIG. 5 has a drawback that errors among the measuring chambers are accumulated and that the measuring chambers need to be switched frequently, and errors occur depending on the switching timing. Furthermore, since the dialysate contains calcium carbonate and the dialyser contains low molecular weight proteins, etc.,
The malfunction of the valve and the change in the volume of the pump due to these cannot be ignored.

"Means for Solving the Problem" According to the present invention, the dialysate is supplied to the dialyzer by the first rotary metering pump, and the dialysate from the dialyzer is drawn by the second rotary metering pump. A first bypass valve is connected in parallel with the first rotary metering pump, and a second bypass valve is connected in parallel with the second rotary metering pump. Means for forming a closed passage is provided between the first rotary metering pump and the second rotary metering pump. The flow rate of the liquid flowing through the closed path is measured by the flow rate measuring means. In the calibration mode, the second bypass valve is opened and the flow rate of the first rotary metering pump is measured by the flow rate measuring means while the closed path is configured, and the flow rate of the second rotary metering pump is measured by opening the first bypass valve. The measurement is performed by the measuring means, and the flow rate difference between the first rotary metering pump and the second rotary metering pump is set to zero by these measurement outputs. In the dialysis mode, the first and second rotary metering pumps are set to the rotation speeds obtained in the calibration mode, and the difference between the dialysate volume flowing into and out of the dialyzer is the third volume. It is pulled by a rotary metering pump. Alternatively, the third rotary metering pump is omitted, and the second rotary metering pump is rotated more than the first rotary metering pump corresponding to the set water removal amount.

[Embodiment] FIG. 1 shows an embodiment of the present invention, in which parts corresponding to those in FIG. 4 are designated by the same reference numerals. In this invention, the liquid supply flow path 15 is provided with a first rotary metering pump 31, and the drainage flow path 17 is provided with a second rotary metering pump 32.
The first bypass valve 33 is provided in parallel with the first rotary metering pump 31.
Is connected, and the second bypass valve 34 is connected in parallel with the second rotary metering pump 32. First rotary metering pump 31
Means for forming a closed passage is provided between the second rotary metering pump 32 and the second rotary metering pump 32. Therefore, in this example, the bypass coupler 35 is provided, the liquid supply flow path 15 is removed from the dialyzer 13 and is connected to one end of the bypass coupler 35, and the drainage flow path 17 is removed from the dialyzer 13 to remove the bypass coupler 35. Allowed to connect to the end. A flow meter 36 is provided in the liquid supply flow path 15 between the dialyzer 13 and the first rotary metering pump 31 to measure the flow rate in the closed passage. Drainage flow path 1 between the dialyzer 13 and the second rotary metering pump 32
A third rotary metering pump 37 is branched and connected to 7.

This device has two modes. The first is the calibration mode,
The second is the dialysis mode. In the calibration mode, the liquid supply flow path 15 and the drainage flow path 17 are removed from the dialyzer 13 and are connected to the bypass coupler 35 to form the closed path. The first bypass valve 33 is closed, and the second bypass valve 34
Is opened and the first rotary metering pump 31 is, for example, 500 m
It operates at a speed of 1 / min, and the second rotary metering pump 32 stops. The flow rate of the first rotary metering pump 31 at this time is measured by the flow meter 36. Next, the first bypass valve 33 is opened, the second bypass valve 34 is closed, the first rotary metering pump 31 is stopped, and the second rotary metering pump 32 is set to, for example, 5
The operation is performed at a speed of 00 ml / min, and the flow rate of the second rotary metering pump 32 at this time is measured by the flow meter 36. The pump speed of the first rotary metering pump 31 or the second rotary metering pump 32 is controlled so that the difference between the measured flow rates of the first and second rotary metering pumps 31, 32 becomes zero. Thus, the rotation speeds of the first rotary metering pump 31 and the second rotary metering pump 32 in the dialysis mode are determined.

In the dialysis mode, the liquid supply flow path 15 and the drainage flow path 17
Is removed from the bypass coupler 35 and connected to the dialyzer 13,
The liquid supply to the dialyzer 13 is started. At this time, the first rotary metering pump 31 and the second rotary metering pump 32 maintain the rotation speed obtained in the calibration mode. The third rotary metering pump 37 operates at a rotation speed corresponding to the amount set by the water removal rate meter. That is, the first rotary metering pump 31 and the second
The rotary metering pump 32 equalizes the inflow and outflow of the dialysate into the dialyzer 13, and the third rotary metering pump 37 forcibly withdraws an amount corresponding to the amount of water removed. In this way, the amount of water removed can be controlled with high accuracy to remove water systematically. However, the rotary metering pump has a change in quantification with time.
By compensating for this drawback, it is possible to realize more precise water removal amount control than the reciprocating pump.

A Moino pump can be used as the rotary metering pump, and a pulse motor can be used as a drive source of this pump. As a flow rate measuring means in the calibration mode, as shown in FIG. 2, a meter 38 is provided on the discharge side of the second rotary metering pump 32.
Is provided, the second bypass valve 34 is opened, and when the liquid is fed by the first rotary metering pump 31, the time required for the liquid to reach the upper reference level from the lower reference level of the measuring instrument 38 is measured. When the first bypass valve 33 is opened and the liquid is fed by the second rotary metering pump 31, the time taken for the liquid to reach the upper reference level from the lower reference level of the measuring device 38 is measured. The rotational speeds of the first rotary metering pump 31 or the second rotary metering pump 32 may be controlled so that the two values become equal. In the example shown in FIG. 2, the rotation speed of the second rotary metering pump 32 is controlled by adding the set amount of water removal to the value obtained in the calibration mode without providing the third rotary metering pump. This is the case.

As shown in FIG. 3, the first opening / closing valve 16 is branched to the liquid supply flow path 15, the second opening / closing valve 18 is branched to the drainage flow path 17, without using the bypass coupler 35 for the construction of the closed path. Road 2
1 may be provided with the third on-off valve 22, and in the calibration mode, the first on-off valve 16 and the second on-off valve 18 may be closed, and the third on-off valve 22 may be opened to form a closed passage through the branch passage 21. . In the example of FIG. 3, a metering mechanism 39 using a cup is provided on the discharge side of the third rotary metering pump 37, the amount of water removed is measured, and the rotation speed of the third rotary metering pump 37 is corrected.

As a structure of the closed passage, the blood flow in the dialyzer 13 may be stopped. The third rotary metering pump 13 may be branched and connected to the inflow side of the dialyzer 13, and the dialysate may be reduced and supplied to the dialyzer 13 by an amount corresponding to the amount of water removed.

"Effect of the device" As described above, according to the present invention, a water removal amount control device capable of controlling the water removal amount with high accuracy by using a rotary metering pump and sufficiently corresponding to a high water removal capacity membrane is provided. realizable.
Compared to the case of using a reciprocating metering pump with a metering chamber, it is not necessary to open and close the valve frequently, and by inserting the calibration mode appropriately, errors do not accumulate,
You can always get the right control.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIGS. 2 and 3 are block diagrams showing other embodiments, respectively.
FIG. 5 and FIG. 5 are block diagrams showing a conventional water removal amount control device.

Claims (1)

[Scope of utility model registration request] 1. A hemodialysis apparatus for supplying dialysate to a dialyzer through a liquid supply flow path to remove waste products from the blood supplied to the dialyzer and discharging the waste together with the dialysate into a drainage flow path. A first rotary metering pump inserted into the liquid supply channel, a second rotary metering pump inserted into the drainage channel, and a first bypass valve connected in parallel with the first rotary metering pump. A second bypass valve connected in parallel with the second rotary metering pump; means for forming a sealed path between the first rotary metering pump and the second rotary metering pump; Flow rate measuring means for measuring the flow rate of the flowing liquid, and first measuring means for measuring the flow rate of the first rotary metering pump by the flow rate measuring means by opening the second bypass valve in the state where the closed path is configured. And the above-mentioned closed path is configured Second measurement means for measuring the flow rate of the second rotary metering pump by the flow rate measurement means by opening the first bypass valve, measurement output of the first measurement means, and measurement output of the second measurement means. And the first rotary metering pump and the second
A means for controlling the amount of water removed from a hemodialysis machine, comprising: means for reducing the flow rate difference from the rotary metering pump to zero.