JPS6259590B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a pressure control device for extracorporeal blood circulating for the purpose of controlling blood pressure in extracorporeal blood circulation such as hemodialysis, hemofiltration, and plasma separation.

<Prior art and its problems> Important factors in hemodialysis include the removal of waste products from the blood and the removal of excess water from the blood. This removal rate per unit time, or ultrafiltration rate, is related to the transmembrane pressure, which is the pressure difference on both sides of the dialysis membrane, and by controlling this pressure, water can be removed as desired. However, the transmembrane pressure is the pressure difference between the blood and the dialysate, and the pressure of the dialysate remains almost constant during dialysis, so the desired ultrafiltration rate cannot be obtained by controlling only the blood pressure. , water removal can be performed as desired.

Conventionally, in order to obtain a desired ultrafiltration rate, blood pressure was detected using a sensor, and based on the signal from the detected value, a clamp placed in the blood circuit was opened and closed to control blood pressure. has been adopted, but it requires a complicated mechanism, making it expensive and economically problematic. Also, special public service in 1977-
The invention of No. 34155 is also for this purpose, in which an inner tube made of a flexible member provided in a path leading blood that has passed through a dialysis machine to a vein is replaced with an outer tube made of a non-flexible member. This device is designed to adjust the pressure by pressurizing the inside of a sealed chamber surrounded by a tube and formed by the outer wall of the inner tube and the inner wall of the outer tube.
There is a risk that the thin membrane may rupture during use, resulting in blood leakage, or that the inner tube of the thin membrane may resonate with the pulsation of the blood pump, causing hemolysis.Also, since it is incorporated into a disposable blood circuit, It has become extremely uneconomical.

<Problems to be Solved by the Invention> The present invention has been made in view of the above problems, and an object of the present invention is to provide an inexpensive and reusable pressure control device that does not require the adoption of a complicated mechanism. .

<Means for Solving the Problems> In order to solve the above-mentioned problems, the present invention provides a system that is linked to changes in the internal pressure of the circuit, which is transmitted via a pressure transmission tube provided on the upstream side of the circuit through which blood flows. an air chamber that is displaced by the air chamber; and an air chamber disposed in contact with the air chamber,
A diaphragm that moves in conjunction with the displacement of the air chamber, one end of which is fixed to the diaphragm and the other end of which is disposed in contact with a flexible tube on the downstream side of the circuit, and which moves in conjunction with the displacement of the diaphragm. an operating rod that is displaced in conjunction with the displacement of the diaphragm; It is comprised of a pressure setting means that can arbitrarily set a pressure corresponding to a desired blood pressure with a small change in pressure against the diaphragm. A pressure control device for extracorporeal circulating blood, characterized in that a chamber is displaced, the diaphragm and the operating rod are displaced by the displacement of the air chamber, and the flexible tube is opened and closed by the displacement of the operating rod. We are hiring.

<Operation of the invention> Next, the operation of the invention will be explained using FIG. 2A and FIG. 2B.

The pressure control device 11 has a piston 15 slidably housed in a closed cylinder 12, and it is assumed that the cross-sectional area of the piston rod 16 is O.
The free end of the piston rod 16 is brought into contact with a flexible tube 17 through which fluid flows, and the tube 17 is opened and closed by the stroke of the piston 15. The sealed cylinder 12 is divided by the piston 15 into a small-capacity air chamber 13 on the piston rod 16 side and a large-capacity air chamber 14 on the opposite side in the stroke range of the piston 15. is piston rod 1
Flexible tube 17 on the upstream side of the contact part with 6
The inner pressure of the flexible tube 17 is equal to that of the flexible tube 17.

In the above configuration, when the fluid pressure in the flexible tube 17 decreases, the pressure in the small-capacity air chamber 13 also decreases to the same value, and the piston 15 moves relatively due to the pressure difference with the large-capacity air chamber 14. As shown in FIG. 1A, the piston rod 16 also moves forward and operates in the direction of closing the flexible tube 17 that the rod 16 abuts, reducing the flow passage cross-sectional area of the tube 17.

Then, due to this decrease in the cross-sectional area of the flow path, the internal pressure of the flexible tube 17 increases, and the internal pressure of the small-capacity air chamber 13 also increases, and the small-capacity air chamber 13 and the large-capacity air chamber 1 are separated.
The movement of the piston rod 16 stops at a position where the internal pressures of the piston rods 4 and 4 are balanced. In this case, since the capacity of the large-capacity air chamber 14 is sufficiently large, the volume change ratio due to the movement of the piston 15 is small, and therefore there is no large change in the internal pressure of the air chamber 14 before and after the movement of the piston 15. The change in stress for 15 is also small.

Furthermore, the internal pressure of the air chamber 14 becomes equal to the internal pressure of the small capacity air chamber 13 due to the movement of the piston 15, so that
The internal pressure of the flexible tube 17 that communicates with this air chamber 13 becomes equal.

Conversely, when the internal pressure of the flexible tube 17 increases, the piston rod 16 moves back in the reverse process as described above, and the movement of the piston rod 16 stops at a position where the internal pressures of the air chambers 13 and 14 are balanced, and the internal pressure of the air chamber 14 decreases. and the internal pressure of the flexible tube 17 become equal.

Therefore, if the internal pressure of the large-capacity air chamber 14 is set in advance to be equal to the desired fluid pressure, that is, the internal pressure of the flexible tube 17, even if the fluid pressure fluctuates, the internal pressure of the flexible tube 17 can be maintained. Can be controlled to set pressure.

<Example> Next, an example of the present invention will be described based on the drawings.

FIG. 1 is a diagram showing a pressure control device according to an embodiment of the present invention, and for the sake of explanation, a part of the blood circuit is also shown.

As shown in FIG. 1, a pressure control device 1 of the present invention
The air chamber 3 is connected to the drip chamber D of the blood circuit C by the pressure transmission tube 7, the actuating rod 6 is fixed to the partition plate 5, and the tube serves as a flexible tube T support means. It consists of a guide 8 and a pressure setting means 4 separated from the air chamber 3 by a diaphragm 5, and the operating rod 6 has its free end connected to the flexible downstream side of the drip chamber D. Tube T
is in contact with.

The air chamber 3 corresponds to the small-capacity air chamber 13 shown in FIG. 2, and is formed to be displaced in conjunction with changes in the internal pressure of the blood circuit C. Therefore, a donut-shaped bellows that can expand and contract up and down in response to the pressure inside the drip chamber D as shown in FIG. 1, a tire tube-shaped flexible bag, or any other suitable shape things can be used.

The partition plate 5 separates the air chamber 3 from the pressure setting means 6, and corresponds to the piston 15 in FIG. 2, and is formed into a flat plate shape from a material that does not easily deform under pressure. When the partition plate 5 is made of a gas-impermeable material, it may constitute a part of the air chamber 3.

The actuating rod 6 corresponds to the piston rod 16 shown in FIG. 2, and is generally formed in a cylindrical shape, and the portion in contact with the flexible tube T is formed to have a relatively small area in accordance with the tube T. As shown in FIG. It may be arranged to be inclined with respect to the flexible tube T, and in this case, it is possible to reduce the displacement of the actuating rod 6 with respect to the flexible tube. Pressure setting means 4
is formed so that it cannot communicate with the air chamber 3 by a partition plate 5, and in this embodiment, the large capacity air chamber 1 shown in FIG.
4, a pressure buffer chamber 42 that communicates with this pressure setting chamber 41 and has a large capacity to compensate for the lack of capacity of the pressure setting chamber 41, a manual pump 43 as a pressurizing means, and a manual pump 43 as a pressurizing means. After the desired pressure is obtained by operating the pump 43, the pump 43
A configuration consisting of forceps 44 for clamping the connecting tube between the pressure buffer chamber 42 and the pressure buffer chamber 42, and a pressure gauge 45 is adopted. The pressure setting chamber 41 is a part that is displaced in conjunction with the displacement of the partition plate 5, and is set to an arbitrary pressure by a manual pump 43, but the pressure setting chamber 41 is formed to have a sufficiently large capacity with respect to the air chamber 3. Because there are
Since the change in pressure on the partition plate 5 caused by the displacement of the partition plate 5 is small, and therefore the internal pressure of the pressure setting chamber 41 is maintained at approximately the set pressure, the pressure setting chamber 41
In this pressure control device configured so that the internal pressure of the air chamber 3 and the internal pressure of the air chamber 3 are balanced, and the internal pressure of the air chamber 3 and the internal pressure of the blood circuit C are balanced, the internal pressure of the blood circuit C is maintained at approximately the set pressure. Ru. Note that the pressure buffer chamber 42 is not necessary if the capacity of the pressure setting chamber 41 is sufficiently large and the change in the internal pressure of the pressure setting chamber 41 due to displacement of the partition plate 5 is small.

As the pressure setting means 4, it is also possible to employ a coil spring or the like. When using a coil spring, adjust the length of the coil spring to the operating rod 6.
It is necessary to make the pressure change of the coil spring sufficiently longer than the stroke of the actuating rod 6 and to reduce the pressure change of the coil spring against the diaphragm 5 that is displaced within the stroke range of the actuating rod 6.
Further, in order to measure the set pressure by the coil spring, it is necessary to provide a pressure gauge in communication with the air chamber 3. The air chamber 3, the partition plate 5, a part of the operating rod 6, and the pressure setting means 4 are the cylinder 1 in FIG.
In FIG. 1, the housing 2, which has a pressure buffer chamber 42 and is provided with a manual pump 43, a pressure gauge 45, and a tube guide 8, has an air chamber. 3, a partition plate 5, a part of the actuating rod 6, and a pressure setting chamber 41 are accommodated, and the free end of the actuating rod 6 protrudes from a through hole provided in the housing 2 to the outside of the housing 2, and is formed into a flexible tube. It is in contact with T. In addition, when it is necessary to add the set pressure, the control target pressure, that is, in the embodiment, the internal pressure of the blood circuit C, is maintained at the set pressure so that it can be easily checked whether the added pressure is maintained at the set pressure. It is practical to provide a pressure gauge in communication with chamber 3. However, if the pressure gauge is connected to the air chamber 3 in a type in which the pressure is set by the manual pump 43, the pointer of the pressure gauge swings left and right due to the operation of the manual pump 43, and the desired pressure is not reached. Setting may be difficult, but such problems can be solved by reducing the cross-sectional area of the tube that connects the manual pump 43 and the pressure setting chamber 41, or by adding a filter to the tube that communicates the air chamber 3 and the pressure gauge. This problem can be solved by providing a tube or by reducing the cross-sectional area of this communication tube.

<Effects of the Invention> As is clear from the above description, the present invention has the following advantages.

(1) It has a simple structure that does not require any other power, and can be applied directly to a normal blood circuit, so it does not resonate with blood pulsation caused by blood pump operation and cause hemolysis.

(2) Blood pulsation is alleviated by the air chamber and pressure setting chamber, so a steady flow can be obtained.

(3) It is economical because it has a simple structure.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a pressure control device according to an embodiment of the present invention, and FIGS. 2A and 2B are explanatory diagrams showing the principle of the present invention. <Explanation of main symbols> 1: Pressure control device, 3:
Air chamber, 4: Pressure setting means, 41: Pressure setting chamber, 4
3: Manual pump, 44: Forceps, 45: Pressure gauge,
5: Partition plate, 6: Operating rod, 7: Pressure transmission tube,
8: Tube Guide.

Claims (1)

[Scope of Claims] 1. An air chamber that is displaced in conjunction with changes in the internal pressure of the circuit, which is transmitted through a pressure transmission tube provided upstream of the circuit through which blood flows, and arranged in contact with the air chamber. a diaphragm which is displaced in conjunction with the displacement of the air chamber, one end of which is fixed to the diaphragm and the other end of which is disposed in contact with a flexible tube on the downstream side of the circuit;
an actuating rod that is displaced in conjunction with the displacement of the diaphragm; a support means that supports the vicinity of the portion of the flexible tube that contacts the actuating rod to prevent the tube from moving; a pressure setting means that is able to arbitrarily set a pressure corresponding to a desired blood pressure, with a small change in pressure relative to the diaphragm; The air chamber is displaced in conjunction with the deviation of the air chamber, the diaphragm and the actuating rod are displaced by the displacement of the air chamber, and the flexible tube is opened and closed by the displacement of the actuating rod. Pressure control device for extracorporeal circulating blood.