JPH0653163B2 - Blood purification device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an ultrafiltration-based blood purification apparatus, and more specifically, to an accurate and continuous ultrafiltration amount of water in blood. The present invention also relates to a blood purification device that can be automatically adjusted.

“Prior Art” As is well known, in artificial dialysis treatment for renal failure patients, dialysate is supplied from a dialysate supply source to a dialyzer connected to the patient's arteries and veins, and the dialysate that has completed dialysis is It has been drained as it is.

On the other hand, in the dialyzer, in addition to the dialysis of waste products contained in the patient's blood, the water in the patient's blood is ultrafiltered to the dialysate side through a dialysis membrane, and the dialysate flows at the inlet flow rate of the dialyzer. The flow rate on the outlet side (drainage liquid) increases by the amount of ultrafiltered water.

In such artificial dialysis treatment, it is important to remove not only waste products in the blood but also excess water, and conversely, if the amount of water removed (water removal) by ultrafiltration becomes large. It will be necessary to make up for it later. Therefore, confirmation and adjustment of the amount of water removed during artificial dialysis are important.

By the way, the amount of water removed is determined by the pressure difference between blood and dialysate acting through the dialysis membrane in the dialyzer and the performance of the dialyzer, and fluctuates depending on these pressure differences and the performance of the dialyzer. Therefore, such a dialyzer requires a mechanism capable of accurately grasping the amount of bodily fluid removed in several hours from the start to the end of dialysis in one dialysis.

As a blood purification device having such a mechanism, a device having a structure shown in FIG. 4 is conventionally known (Japanese Patent Publication No. 61-5735).
issue).

In the figure, blood is drawn to a blood outlet 1 from a patient, sent to a blood inlet 4 of a dialyzer 3 by a blood pump 2, and after exchanging a substance in the dialyzer 3, a throttle valve 6 is opened from a blood outlet 5. After that, the blood is returned to the patient from the blood return port 7 to the patient. The blood pressure inside the dialyzer 3 is adjusted by the throttle valve 6, and the difference between this pressure and the dialysate side pressure causes the ultrafiltration amount.
(Water removal amount) is determined. Reference numeral 8 is a blood pressure indicator.

On the other hand, the dialysate is supplied through the pipe 9, and the stop valve 10,
The three-way switching electrode valve 13 is reached via the flow meter 11 and the throttle valve 12.
The solenoid valves 13 and 14 are structured to be operated by a timer 15, and are sent from the solenoid valve 13 to the solenoid valve 14 via a dialysate metering pump 16.

The dialysate metering pump 16 is configured to alternately repeat feeding and draining liquids at regular time intervals by operating the solenoid valves 13 and 14. In the liquid delivery cycle of the pump 16, the dialysate is sent from the solenoid valve 13 through the solenoid valve 14 to the dialysate inlet 17 of the dialyzer 3 by the pump 16, and after the substance is exchanged in the dialyzer 16, the dialysate is delivered from the outlet 18. It is stored in a measuring container 20 through a negative pressure pump 19. Throttle valve 21 and negative pressure pump (dialysis fluid metering pump) 19
Is provided for giving a negative pressure to the dialysate in the dialyzer 3, the negative pressure is adjusted by the throttle valve 21, and the pressure is indicated by the pressure gauge 22.

Next, in the drainage cycle, the liquid stored in the measuring container 20 is drawn out from the pipe 23 by the pump 16 and discharged to the drainage port 24 via the electromagnetic valves 13 and 14. At this time, the delivery of dialysate is stopped. The valve 25 is used for draining the measuring container 20.

In the above-mentioned configuration, the measuring container 20 stores an amount obtained by adding the dialysate sent by the pump 16 for a certain period of time and dewatering of the dialyzer 16 for the same certain period of time, and the same pump at the same constant period of time in the next cycle. Drained by 16. Therefore, if the fluctuation of the flow rate of the pump 16 in a short time can be ignored, only the amount of water removed remains in the measuring container 20.

"Problems to be Solved by the Invention" By the way, the above-described conventional blood purification apparatus has the following problems.

That is, in the blood purification apparatus having the above configuration, when the water removal amount is controlled by the blood pump 16 and the throttle valve 6, and the negative pressure pump 19 and the throttle valve 21, the dialysate side set by the pumps and the throttle valve is set. There is a problem that the amount of liquid removed actually becomes larger than the amount of liquid removed theoretically due to the pressure difference between the liquid side and the blood side.

As a result of intensive experiments conducted by the present inventors on this problem, the following findings have been obtained. In other words, it was found that the actual amount of water removed that was larger than the theoretical amount was not removed from the patient's blood, and the total amount of dialysate was reduced by that amount. When various experiments were conducted on the cause, the decrease in the total amount of dialysate was instantaneous when each solenoid valve 13, 14 was switched by an electric signal, but there was a time when all solenoid valves were open. At this moment, it was found that the dialysate present in each of the conduits of the dialysate supply system and the dialysate discharge system became in a communication state, and the dialysate was aspirated in excess at this time.

Therefore, the above-mentioned conventional blood purification device still has a problem that the amount of liquid removed cannot be accurately measured and controlled.

"Means for Solving Problems" The blood purification apparatus of the present invention is provided in a cylinder in which a liquid suction port is formed at one end of a side peripheral surface and a drain port is formed at the other end. Two pistons having a length dimension longer than the distance dimension between the liquid suction port and the liquid discharge port are movably housed in series so as to be movable independently of each other and at the same time with a predetermined distance from each other. It is characterized in that the dialysate metering pump in the device is configured by a metering pump that is set so that it can be linked while maintaining it, and that all solenoid valves are omitted to simplify the device. .

[Operation] The metering pump having the above-described configuration can be operated as follows. First, at the time of liquid absorption, one piston is fixed in front of the liquid suction port, and the other piston that was initially in contact with this one piston has a predetermined distance in the direction of the liquid discharge port (between the liquid suction port and the liquid discharge port). Move less than distance).
At this time, the dialysate is sucked between the two pistons. Then, the two pistons are interlocked with each other in the drain port direction while maintaining the distance. During this interlocking, when the liquid suction port is open, the other drain port is surely blocked by the other piston, and conversely, when the liquid drain port is open, one piston is sucking. The liquid outlet is blocked. Stop and fix the other piston without passing through the drain port. Then, one piston is moved toward the other fixed piston until it abuts. As a result, the dialysate filled between the pistons can be discharged from the drainage port. Therefore, by using this metering piston, the volume occupied by the installation is increased, and the accurate supply and discharge of the dialysate and the blocking of each flow path therebetween are surely performed without using a large number of electromagnetic valves that are difficult to control. It is possible,
As a result, the amount of liquid removed can be accurately controlled.

Next, the present invention will be described in more detail with reference to Examples.

[Example] The feature of the blood purification apparatus of this example is that, as shown in FIG. 1, the metering pump 30 outlined above as a dialysate metering pump is used.
The use of a, 30b and the accompanying omission of the solenoid valve altogether.

As shown in FIG. 2 (a), the metering pump 30a (30b) has two pistons 32a and 32b slidably accommodated in a cylindrical cylinder 31, and its capacity is variable. . Cylinder
A liquid suction port 31a is formed at one end of the outer peripheral surface of 31, and a liquid discharge port 31b is formed at the other end. Also,
The pistons 32a and 32b have the same size, and their length L
Is set longer than the distance dimension 1 between the liquid supply port 31a and the liquid discharge port 31b. These pistons are individually driven by a motor or the like, and are set so as to be synchronously driven by an electric signal. Explaining how to drive the pump 30a (30b) by this motor, first, when absorbing the liquid, one piston 32a is fixed in front of the liquid suction port 31a, and the other piston that was initially in contact with this one piston 32a is fixed. 32b is moved in the direction of the drainage port 31b by a predetermined distance (distance smaller than the distance l between the liquid suction port and the drainage port) [Fig. 2 (b) → (a)]. At this time, the two pistons 32
Dialysate is sucked between a and 32b. Then, the two pistons 32a and 32b are interlocked in the direction of the drainage port 31b while maintaining the distance. In this way, the other piston 32b
Immediately after passing through the drainage port 31b, the robot stops and is fixed. Then, as shown in FIG. 2 (c), one piston 32a is moved toward the other piston 32b in a fixed state until it abuts. This allows each piston 32a, 32b
The dialysate filled in between can be led out from the drain port 31b. After the dialysate has been drawn out and the pistons 32a and 32b are in contact with each other, one piston 32a remains in the contact state.
Moves until it has finished passing through the liquid supply port 31a. As a result, one operation of the pump 30a (30b) is completed, and thereafter, this operation is repeated. During this one operation, the liquid suction port 31a and the liquid discharge port 31b are simultaneously blocked, or at least one of them is blocked. That is, when the liquid suction port 31a is opened, the other drainage port 31a is reliably blocked by the moving piston 32b, and conversely, when the drainage port 31b is opened, One of the moving pistons 32a blocks the liquid suction port 31a.

In the apparatus of this embodiment, one of the two dialysate metering pumps 30a and 30b having the above-described structure and action is set to have a smaller capacity (corresponding to the amount of water removed) than the other pump 30a, and these pumps 30a and 30b are set. Are used by connecting them to each pipeline as shown in FIG. That is, in one pump 30a, the dialysate supply pipe 9 is connected to the liquid suction port 31a, and the drainage port 31b is connected to the dialysate inlet 17 of the dialyzer 3 through the pipe 33 having the throttle valve 21.
Connect to. In the other pump 30b, a pipe 33 connected to the dialysate outlet 18 of the dialyzer 3 is connected to the liquid suction port 31a and a drain pipe 35 is connected to the drain port 31b. The pistons 32a and 32b are set by a control device (not shown) so that the piston operations are synchronized with each other so as to shift from each other by a half cycle.

In the blood purification apparatus of the present invention having the above-described configuration, first, one piston 32a of one pump 30a is stopped before the liquid supply port 31a, and the other piston 32b is drained 3
Move towards 1b. On the other hand, in the other pump 30b, while the other piston 32b is stopped near the drainage port 31b, one piston 32a near the liquid supply port 31a is moved toward the other piston 32b, and Then, the abutted pistons 32a and 32b are returned to the initial state. As a result, supply of dialysate and discharge of used dialysate are blocked, while supply of dialysate to one pump 30a and discharge of drainage from the other pump 30b are performed. When the filling of the dialysate into one pump 30a is completed, then one pump 30a
At a, one piston 32a in the vicinity of the liquid suction port 31a is moved toward the other piston 32b in a stopped state in the vicinity of the liquid discharge port 31b. As a result, the dialysate in the one pump 30a is supplied to the dialyzer 3. At the same time, in the other pump 30b, one piston 32a is stopped in the vicinity of the liquid supply port 31a, the other piston 32b is moved toward the liquid discharge port 31, and the dialysate supplied to the dialyzer 3 is supplied. The same amount of used dialysate is sucked into the other pump 30b. In this way, the supply and discharge operations after dialysis are repeated, and the difference between the supplied dialysate volume and the discharged dialysate volume becomes the water removal volume.

In the above embodiment, as shown in FIG. 3, the pumps 30a and 31b are adjusted to have the same capacity and the other pump is adjusted.
If a small capacity pump (water removal pump) 36 having the same structure as the pumps 30a and 30b is provided in the pipe 34 in front of 30b and is configured to draw with a slight negative pressure, the amount of water removed can be directly reduced by this small capacity pump 36. Can be measured.

[Advantages of the Invention] As described above, according to the blood purification device of the present invention, accurate installation of the dialysate can be performed without using a large number of solenoid valves that require a large installation volume and are difficult to control. It is possible to reliably perform the discharge and the blocking of each flow path therebetween, and as a result, it is possible to accurately control the liquid removal amount.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the blood purification device of the present invention, and FIGS. 2 (a), (b) and (c) are configuration diagrams of a dialysate metering pump which is a main part of the blood purification device. FIG. 3 is a block diagram showing another embodiment of the blood purifying apparatus of the present invention, and FIG. 4 is a block diagram of a conventional blood purifying apparatus. 2 ... Blood circulation pump, 3 ... Dialyzer, 30a, 30b ... Dialysate metering pump, 31 ... Cylinder, 31a ... Cylinder suction port, 31b ... Cylinder drainage port, 32a, 32b ... … Piston, 33 …… Piping (dialysis fluid supply side piping), 34 …… Piping (dialysis fluid drainage side piping), 35 …… Drainage pipe, 36 …… Water removal pump, l …… Suction port and drain Distance dimension to liquid port, L ... Piston length dimension.

Claims (1)

[Claims] 1. A dialysate supply side pipe of a dialyzer for bringing blood and dialysate into contact with each other through an ultrafiltration membrane to move waste and water from the blood into the dialysate, and drainage of the dialyzer. A dialysate metering pump is provided in each of the side pipes, and a liquid suction port is formed at one end of the outer peripheral surface and a liquid discharge port is formed at the other end of the pump. Two pistons having a length dimension longer than the distance dimension to the drainage port are housed in series and movably, and the pistons can move separately and at the same time, interlock while maintaining a predetermined distance from each other. A blood purification apparatus characterized in that the dialysate metering pump is constituted by a metering pump set so as to be able to do so.