JPH0630201Y2 - 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 flow path 15 to the dialyzer 13 via the first on-off valve 16, and the dialyzer 13
The dialysate is further drained from the drainage channel 17 via the second on-off valve 18 and further drawn 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. The relationship between the dialysate-side pressure Q and the blood-side pressure P, PQ (TMP: permeable membrane pressure), 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, the dialysate is flown into the dialyzer 13, and the TMP at this time is controlled to be the TMP measured above. To do.

Further, 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, and when the dialysate is being supplied from the metering chamber 25b of the reciprocating metering pump 25 to the dialyzer 13, the dialyzer 13 pumps the dialysate. Of the dialysate to be supplied to the metering chamber 26a of the metering pump 26, and the dialysate taken into the metering chamber 26b is discharged. On the contrary, the dialysate in the measuring chamber 26a of the metering pump 26 is transferred to the dialyzer 13
When supplying the dialysate from the dialyzer 13,
b, the metering pump 25 takes in the dialysate to be supplied to the measuring chamber 25b, and drains the dialysate in the measuring chamber 25a.

The dialysate discharged from the dialyzer 13 is also drawn by the water removal pump 27, and the amount of dialysate drawn by the water removal pump 27 is adjusted by the metering pump 25 or 26.
The difference between the amount supplied to the dialyzer 13 and the amount supplied from the dialyzer 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 invention" 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 internal pressure of 13 is different and causes an error.In recent dialysers, the amount of water removed per TMP is about 5 times that of the conventional one, 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 the switching timing causes an error. Further, since the dialysate contains calcium carbonate and the downstream liquid of the dialyzer contains low molecular weight proteins and the like, malfunction of the valve and change in the volume of the pump 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. In the calibration mode, the outlet of the first rotary metering pump and the inlet of the second rotary metering pump are connected by a closed path. That is, this closed passage is designed so that no liquid flows in or out except for the pump. The flow rate difference between the first rotary metering pump and the second rotary metering pump is detected in the state of being connected by the closed path, and the first rotary metering pump and the second rotary metering pump are detected according to the flow rate difference detection output. The flow rate difference with the pump is configured to zero. A third rotary metering pump is connected to a liquid supply flow path between the first rotary metering pump and the dialyzer,
The dialysate from the liquid supply flow path is returned to the inlet of the first rotary metering pump by the third rotary metering pump.
The third rotary metering pump is driven in dialysis mode,
The dialysate, which is smaller than the flow rate of the second rotary metering pump by the ultrafiltration amount (removed water amount), is supplied to the dialyzer.

[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.
Means are provided for forming a closed passage in which only the liquid supplied from the first rotary metering pump 31 and all of it is supplied to the second rotary metering pump 32. Therefore, in this example, the bypass coupler 33 is provided, the liquid supply flow path 15 is removed from the dialyzer 13 and is connected to one end of the bypass coupler 33, and the drainage flow path 17 is removed from the dialyzer 13 to bypass the bypass coupler 33. It can be connected to the other end of. Flow rate difference detection means for detecting a flow rate difference between the first rotary metering pump 31 and the second rotary metering pump 32 in the state where the closed passage is formed is provided. In this example, as the flow rate difference detecting means, the first
A pressure measuring device 34 for detecting hydraulic pressure is provided in the closed path between the rotary metering pump 31 and the second rotary metering pump 32. The third rotary metering pump 35 is branched and connected to the liquid supply flow path 15 between the first rotary metering pump 31 and the dialyzer 13, and the discharge side of the third rotary metering pump 35 is the first rotary metering pump. It is connected to the inflow side of 31.

This device has two modes. The first is the calibration mode,
The second is the dialysis mode. First, the calibration mode will be described. In the calibration mode, the first rotary metering pump 31
A closed path is provided between the second rotary metering pump 32 and the second rotary metering pump 32. That is, the liquid supply flow path 15 is removed from the dialyzer 13 and connected to the bypass coupler 33, the drainage flow path 17 is removed from the dialyzer 13 and connected to the bypass coupler 33, and the third rotary metering pump 35.
Will stop. At this time, all the liquid from the first rotary metering pump 31 is supplied to the second rotary metering pump 32, and the other liquids are not supplied to the second rotary metering pump 32.

In this state, the output of the pressure measuring device 34 is monitored. If the measured pressure shows an upward trend, the first rotary metering pump 31
Is larger than the flow rate of the second rotary metering pump 32, and if the pressure measured by the pressure measuring device 34 decreases, the flow rate of the first rotary metering pump 31 becomes smaller than that of the second rotary metering pump 32. Flow rate of less than. In this way, the pressure measuring device 34 detects the flow rate difference between the first rotary metering pump 31 and the second rotary metering pump 32.

The pump speed of the first rotary metering pump 31 or the second rotary metering pump 32 is controlled so that the detected flow rate difference becomes zero, that is, the measured pressure of the pressure measuring device 34 does not change. As a result, the rotation speeds of the first rotary metering pump 31 and the second rotary metering pump 32 in the dialysis mode are determined.

Next, the dialysis mode will be described. The liquid supply flow path 15 is disconnected from the bypass coupler 33 and connected to the dialyzer 13, and the drainage flow path 17 is disconnected from the bypass coupler 33 and connected to the dialyzer 13 to start liquid transfer to the dialyzer 13. At this time, the first rotary metering pump 31 and the second rotary metering pump 32
Maintains the number of revolutions determined in calibration mode. The third rotary metering pump 35 is operated at a rotation speed corresponding to the amount set by the water removal rate setting device. Therefore, the dialysate supplied from the first rotary metering pump 31 is drawn by the third rotary metering pump 35 by the amount of water removed, supplied to the dialyzer 13, and drawn by the third rotary metering pump 35. Water will be removed by the dialyzer 13 by the amount. In this way, the amount of water removed can be controlled with high accuracy to remove water systematically. It should be noted that the rotary metering pump is accompanied by a change in quantification property over time, but by calibrating this in a calibration mode and compensating for this drawback, it is possible to realize water removal amount control with higher accuracy than the reciprocating pump. The dialysate drawn by the third rotary metering pump 35 is supplied to the inlet of the first rotary metering pump 31 and is effectively used.

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 shown in FIG. 2, a measuring device 36 such as a measuring cup is provided on the discharge side of the third rotary metering pump 35, the amount of water removed is measured, and the rotation speed of the third rotary metering pump 35 is corrected. You can also As shown in FIG. 3, the liquid supply flow path 15 is provided with a first opening / closing valve 16, the drainage flow path 17 is provided with a second opening / closing valve 18, and the branch path 21 is provided with a third opening / closing valve 22. The first on-off valve 16 and the second on-off valve 18 are closed, and the third
The on-off valve 22 may be opened to form a closed passage through the branch passage 21. A means for stopping the flow of blood flowing in and out of the dialyzer may be provided as a means for forming the closed passage.

[Advantage of Invention] As described above, according to this invention, since the water removal amount can be controlled with high accuracy, it is possible to realize a water removal amount control device that can sufficiently cope with a high water removal capacity membrane. Compared with the case of using a reciprocating metering pump with a measuring chamber, it is not necessary to open and close the valve frequently, and by inserting the calibration mode properly, error is not accumulated and correct control is always performed. be able to. Compared with the case where the third rotary metering pump 35 is provided on the drainage flow path 17 side, there is no risk of the third rotary metering pump 35 becoming dirty. Further, the liquid drawn by the third rotary metering pump 35 is effectively reused.

[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 (2)

[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 in the liquid supply flow path, a second rotary metering pump inserted in the drainage flow path, a discharge port of the first rotary metering pump, and the second rotary metering Means for connecting the inflow port of the pump with a closed path, and flow rate difference detection means for detecting a flow rate difference between the first rotary metering pump and the second rotary metering pump in the state of being connected with the closed path. The means for reducing the flow rate difference between the first rotary metering pump and the second rotary metering pump to zero on the basis of the detection output of the flow rate difference detecting means, and between the first rotary metering pump and the dialyzer. Connected to the liquid supply channel, Ultrafiltration volume control device of the hemodialysis apparatus includes a third rotary metering pump for feeding back to the inlet of said first rotary metering pump 析液, the. 2. The hemodialysis machine according to claim 1, further comprising a measuring device which is provided on a discharge port side of the third rotary metering pump and measures a dialysate discharged from the third rotary metering pump. Water volume control device.