JPH0622611B2 - Dialysis machine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a dialysis device in which the amount of water removed (ultra-excessive flow) can be directly controlled by a water removal pump regardless of the ultracapacity.

<Prior Art> Conventionally, in a dialysis machine, a tubular membrane partitions an inner chamber and an outer chamber, and blood and dialysate are flown in the opposite directions, respectively.
A dialyzer for dialysis and water removal of blood is used. In order to remove water as desired, the pressure on the blood circuit side and the pressure on the dialysate circuit side are measured across the membrane of the dialyzer, and the overpressure TMP, which is the difference between these pressures, becomes the set ultraoverpressure. Thus, for example, the negative pressure pump provided on the dialysate circuit side is controlled.

The limit capacity UFRP of the dialyzer decreases with the passage of time, and desired water removal cannot be performed if the set overpressure remains constant. Conventionally, an error due to a decrease in the ultracapacity UFRP has been corrected by the method disclosed in JP-A-59-2749. In this conventional example, a device for measuring the ultracapacity UFRP of the dialyzer is provided, the ultracapacity is measured at predetermined intervals during artificial dialysis, and desired water removal can be performed based on the measurement result. The new set overpressure is recalculated and the negative pressure pump is controlled so that the overpressure TMP becomes the set overpressure.

However, such a device requires a means for measuring ultracapacity, which complicates the structure, and is in the middle of artificial dialysis (required time: about 5 hours) (for example, every 30 minutes).
Since it is necessary to measure the ultracapacity a number of times, there are drawbacks such that dialysis cannot be performed during that period and an error occurs in the ultracapacity UFRP.

On the other hand, for example, Japanese Patent Publication No. 56-82 proposes a system in which a dialysate circuit including the dialyzer is used as a closed circuit and water is removed from the closed circuit by a water removal pump. In this known example, two or more dialysate containers divided into two chambers by a displaceable partition wall are provided, and one chamber of one dialysate container communicates with the dialysate inlet of the dialyzer, and the other chamber A chamber is connected to a dialysate outlet of the dialyzer to form a closed circuit of dialysate, the dialysate is supplied from the one chamber to the dialysate inlet, and the used dialysate is discharged from the dialysate outlet. According to the displacement of the partition wall, it is made to flow out to the other chamber, and water is removed by a water removal pump provided in the middle of this closed circuit.
The same operation is repeated by switching to the other dialysate container.

In the case of such a device, there is an advantage that desired water removal can be performed by the water removal pump irrespective of reduction in the ultracapacity of the dialyzer. However, a large number of valves are required for switching the flow path, and in addition to the water removal pump, pump means for sending a fixed volume of dialysate to the dialyzer must be provided, which complicates the mechanism. there were.

<Problems to be Solved by the Invention> A technical problem to be solved by the present invention is to realize a dialysis device capable of achieving a target water removal amount regardless of ultracapacity by controlling a water removal pump with an extremely simple configuration. To do.

<Means for Solving the Problems> In order to achieve such an object, the present invention provides a dialysis apparatus that causes a dialysate to flow through a dialyzer and removes water from blood passing through the dialyzer. An outlet-side flow meter for measuring the flow rate of the dialysate, and a dialysate delivered from the outlet-side flow meter when the dialysate flowing through the dialyzer is passed through the dialyzer to the outlet-side flow meter. A constant flow rate pump to flow a fixed flow rate to the flow rate, a water removal control pump that detects the output of the outlet side flow meter and controls the flow rate of the required water removal rate to the outlet side dialysis circuit, and the dialyzer. When bypassed, calibration data of the increased output per unit flow rate is obtained from the output increase amount of the outlet side flow meter when a constant flow rate is made to flow by the constant flow rate pump, and It is characterized by comprising a control unit for controlling the water removal control pump to obtain the desired ultrafiltration volume the calibrated based on the output of the outlet flow meter the calibration data when.

<Operation> The above-mentioned technical means operates as follows. That is, during dialysis,
A predetermined amount of dialysate is caused to flow through the inlet side dialysate circuit, and the water removal control pump is such that the difference between the flow rate through the inlet side dialysate circuit and the flow rate through the outlet side dialysate circuit is the target water removal amount. To remove water.

In order to perform such control, during calibration, the inlet-side flow rate detection means and the outlet-side flow rate detection means have zero characteristics without flowing dialysate, and span characteristics with flowing dialysate at a predetermined flow rate. Is measured, and the flow rate characteristics of the inlet side flow rate detecting means and the outlet side flow rate detecting means and their correlation are obtained from these measurement results. Further, for example, a constant dialysate is caused to flow from the upstream side of the outlet side flow rate detecting means by the constant flow rate pump, and the flow rate characteristic (sensitivity) per unit flow rate of the outlet side flow rate detecting means is measured.

Based on the flow rate characteristics derived from these measurement results, the output when the target water removal amount is added to the dialysate of the reference flow rate is obtained, and during dialysis, the output of the outlet side flow rate detection means is set to this value so that Water removal control Pump is controlled to remove water.

<Example> An example of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an apparatus according to an embodiment of the present invention. In the figure, 1 is a patient, and 2 is a schematic dialyzer, in which a tubular membrane 2 _a is partitioned into an inner chamber 2 _b and an outer chamber _{2 c} , and blood and dialysate flow in opposite directions. 3 is a blood circuit between the patient 1 and the blood side inlet 2 _b1 of the dialyzer 2, 4 is a blood circuit between the blood side outlet 2 _b2 of the dialyzer 2 and the patient 1, 5
Is an inlet side dialysate circuit connected to the dialysate side inlet 2 _c1 of the dialyzer 2, and 6 is an outlet side dialysate circuit connected to the dialysate side outlet 2 _c2 of the dialyzer 2.

7 is a bypass circuit connecting the inlet dialysate path 5 and the outlet dialysate circuit 6; 8 is an inlet flow meter provided in the inlet dialysate circuit 5 upstream of the bypass circuit 7; 9 is a bypass circuit 7; It is an outlet-side flow meter provided in the outlet-side dialysate circuit 6 located further downstream. For these flow meters, for example, a differential pressure type flow meter or an electromagnetic flow meter is used. Reference numeral 10 is a constant flow valve that allows a constant flow rate of dialysate to flow through the inlet side dialysate circuit 5. Reference numeral 11 is a circuit that connects the upstream side and the downstream side of the outlet side flow meter 9.

P ₁ is a blood pump that feeds blood from the patient 1 to the dialyzer 2, and P ₂ is a water removal control pump provided in the outlet side dialysate circuit 6, for example, a gear pump is used. P ₃ is a constant flow pump provided in the circuit 11, and for example, a tubing pump, a plunger pump or the like is used. V ₁
Is a valve provided in the inlet dialysate circuit 5 between the bypass circuit 7 and the dialyzer 2, V ₂ is a valve provided in the outlet dialysate circuit 6 between the dialyzer 2 and the bypass circuit 7, V ₃ Is a valve provided in the bypass circuit 8,
V ₄ is a valve provided in the inlet dialysate circuit 5 upstream of the constant flow valve 10.

The CNT is a control unit, and a multiplexer 12 for switching detection signals from the flowmeters 8, 9 therein, an A / D converter 13, C
A PU 14, a water removal amount setting device 15, a drive circuit 16 and the like are included.

With such a configuration, the valve V ₃ is opened and the valves V ₁ , V _{2 are}
Is closed and the constant flow rate pump P ₃ is stopped, the characteristics of the inlet side flow meter 8 and the outlet side flow meter 9 and their correlation are obtained. FIG. 2 is an explanatory diagram for explaining this operation. First, the zero point outputs Z _I1 and Z _O1 of the inlet side flow meter 8 and the outlet side flow meter 9 are measured with the valve V ₄ closed. Next, the valve V ₄ is opened and a dialysate having a constant flow rate Q _D1 is flown from the constant flow valve 10, and the span point outputs S _I1 and S _O1 of the inlet side flow meter 8 and the outlet side flow meter 9 at that time.
Is measured. From these measurement results, the flow rate / output characteristic of the inlet side flow meter 8 (dotted line) and the flow rate / output characteristic of the outlet side flow meter 9 /
Output characteristics (solid line) is determined, between the output _{S O} output _{S I} and the outlet flow meter 9 the inlet side flow meter 8 Based on _{this, S O = K (S I} -α) ... (1 ) Is established.

However, it is _{α = Z I1 -Z O1 K =} (S I1 -Z I1) / (S O1 -Z O1).

Then, by operating the constant flow pump P ₃ in a state in which the constant flow valve 10 was flushed with dialysate at a constant flow rate Q _b1, flowing dialysate prescribed flow rate from the downstream side of the outlet side flow meter 9 as indicated by an arrow Calibrate the flowmeter sensitivity. FIG. 3 is an explanatory diagram for explaining this sensitivity calibration. In the state before the constant flow rate pump P ₃ operates, the reference flow rate of Q _D1 is flowing, and the output of the flow meter 9 is S _O1 . When the constant flow rate pump P ₃ is driven in this state to flow the reference flow rate ΔQ _D , the output S _O2 is obtained.
From this, the sensitivity A per unit flow rate of the outlet side flow meter 9
Obtained in _S (calibration data) _{A S = (S O2 -S O1} ) / △ Q D ... (2).

When the target ultrafiltration volume and UF _S, output deviations corresponding to △ S is _{△ S = UF S × {(} S O2 -S O1) / △ Q D} ...
(3) can be obtained.

During dialysis, the constant flow rate pump P ₃ is stopped and the valves V ₁ , V ₂ ,
V ₄ is opened, valve V ₃ is closed, and a constant flow rate dialysate is passed through dialyzer 2 from constant flow rate valve 10. Based on the output of the inlet side flow meter 8, the reference output S _O1 of the outlet side flow meter 9 with respect to the reference flow rate flowing at that time is obtained by using the equation (1). Next, the blood pump P ₁ is rotated and the output S _O of the outlet side flow meter 9 is
There by controlling the _{S O = S O1 + △ S} ... (4) and the water removal control Ponpo _{P 2} such that, water removal of the target ultrafiltration volume UF _S is performed.

Here, regarding the output side flow meter 9, the reference output S _O1 is taken into consideration. However, if only the amount of water removed is taken into consideration,
The water removal amount may be obtained by calibrating only the relationship of the equation (3).

The reason why the correlation and sensitivity of the two flowmeters are measured and the control is performed based on the measurement result is to control the entire dialysis machine with high accuracy.

In the case of the apparatus of the embodiment of the present invention shown in FIG. 1, the outlet side flow meter 9
A constant flow rate pump P ₃ is used as a means for flowing a specified flow rate in this, and this part is a combination of a pump P ₄ and a flow meter 17 as shown in FIG. _4, and controls the pump P ₄ to control the outlet side flow meter. 9 may be configured so that a specified flow rate is supplied.

Further, in the case of the apparatus of the embodiment of the present invention shown in FIG. 1, the circuit 11 is connected to the upstream side and the downstream side of the outlet side flow meter 9 to circulate the dialysate. The fluid provided with the outlet side flowmeter 9 branch circuit 18 may be supplied from the upstream side of the constant flow valve 10 as shown in FIG.

<Advantages of the Invention> According to the present invention, when the dialyzer is bypassed, the calibration data of the increased output per unit flow rate is obtained from the output increase amount of the outlet side flow meter when a constant flow rate is caused to flow by the constant electric charge pump, and during dialysis Since the output of the outlet side flowmeter is calibrated based on this calibration data, water removal can be performed accurately. Furthermore, the calibration of the flowmeter may be performed before the treatment and does not deteriorate the dialysis efficiency.

[Brief description of drawings]

FIG. 1 is a block diagram of an apparatus of the present invention, FIGS. 2 and 3 are explanatory views for explaining the operation of the present invention, and FIGS. 4 and 5 are apparatus of the present invention of FIG. FIG. 6 is a configuration diagram showing another specific example of the constant flow rate supply means in FIG. 1 ... Patient, 2 ... Dializer, 3,4 ... Blood circuit, 5 ... Inlet dialysate circuit, 6 ... Outlet dialysate circuit, 7 ... Bypass circuit, 8 ... Inlet flow meter, 9 ……
Outlet side flow meter, 10 ... Constant flow valve, 17 ... Flow meter, 1
8 ...... branch circuit, _{P 1} ...... blood pump, _{P 2} ...... water removal control pump, _{P 3} ...... constant flow pump, _{P 4} ...... pumps, C
NT: Control unit

Claims (1)

[Claims] 1. A dialyzer for flowing a dialysate into a dialyzer to remove water from blood passing through the dialyzer, comprising: an outlet side flow meter for measuring a flow rate at an outlet side of the dialyzer; and a dialysate flowing through the dialyzer. A constant-flow pump that flows a dialysate delivered from the outlet-side flow meter by adding a constant flow rate to the outlet-side flow meter when flowing through the outlet-side flow meter by bypassing the dialyzer, and the outlet-side flow meter. The output of the water removal control pump for controlling the flow rate of the outlet side dialysis circuit to the flow rate of the required water removal amount, and the constant flow rate by the constant flow rate pump when the dialyzer is bypassed The calibration data of the increased output per unit flow rate is obtained from the increased output of the outlet side flow meter, and the output of the outlet side flow meter during dialysis is calculated based on this calibration data. A dialysis apparatus comprising: a control unit that controls the water removal control pump so as to obtain a desired water removal amount.