JPS6354392B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a blood circulation device in a blood circuit of a hemodialysis device used in an artificial kidney device or the like.

(Prior art) Hemodialysis, which is performed using an artificial kidney device (dialysis device), is used to purify blood by eliminating waste products from the body or taking in what is needed instead of the kidneys when the human body suffers from kidney failure. It is widely used to carry out.

FIG. 10 shows an example of a conventional dialysis device, which uses a positive pressure method. In Figure 10, cannula 1a is attached to the blood vessels of the limbs of body A.
1b is punctured to serve as an entrance and exit for extracorporeal circulation of blood. Cannula 1a by blood pump 2
A constant flow rate of blood flowing out from the dialyzer 3 is supplied to the dialyzer 3, and a constriction is created in the tube 5 by the constrictor 4 to generate positive pressure in the blood inside the dialyzer 3.
Air chambers 6a, 6b and pressure gauges 7a, 7b are provided at the blood inlet and outlet of the dialyzer 3,
Use this as a guide to know the ultrafiltration pressure. A supply path 8a and a discharge path 8b are connected to the dialyzer 3, and a separately prepared dialysate is supplied thereto. To perform hemodialysis using this conventional dialysis device, while continuously supplying dialysate from the supply path 8a, the blood pump 2 is rotated, the diaphragm 4 is throttled, and a positive pressure is generated, and the pressure gauge 7a,
Check 7b and adjust the ultrafiltration pressure to an appropriate level.

By the way, during hemodialysis, the phenomena that occur inside the dialyzer are the movement of substances and water due to osmotic pressure and the movement of water due to ultrafiltration.If water is also considered a substance, this movement of substances is It is known that there is a relationship: speed of mass transfer = concentration gradient / resistance. According to this, the rate of mass transfer is proportional to the concentration gradient and inversely proportional to the resistance. In addition to the resistance of the dialysis membrane itself, the resistance includes resistance due to the fluid film that exists along the dialysis membrane. Figure 11 is _a diagram to explain the concentration gradient inside and outside the dialysis membrane and the fluid film _.
When the overall mass transfer coefficient is K, the transfer rate N _A of the substance per unit area of the membrane can be expressed as N _A =K (C _B - C _D ). In addition, the membrane transfer coefficients of the substance on the blood side and dialysate side are K _B and K _D , respectively.
If the diffusion coefficient of the substance in the dialysis membrane is D _H and the membrane thickness is L, then 1/K = 1/K _B + L/D _H + 1/K _D , and the total resistance 1/K is the blood side membrane, It is known that it is equal to the sum of the resistances of the dialysis membrane and the membrane on the dialysate side (Artificial Dialysis Research Society Journal 1969)
Volume 2, Issue 2, P98 onwards).

Therefore, in order to increase dialysis efficiency using the same dialyzer, the flow rate of blood and dialysate should be increased to generate turbulence on the surface of the dialysis membrane and reduce membrane resistance. good. Regarding this only on the blood side, dialysis efficiency increases if the blood flow rate is made as fast as possible, but there is a limit to the flow rate of blood that can be circulated extracorporeally from body A, approximately 150 to 200.
ml/min. Therefore, in conventional dialysis methods, blood is taken out as much as possible within a limit and continuously passed through the blood, and the dialysis efficiency in this respect has not been high.

(Problems to be Solved by the Invention) The present invention has been made to solve the above-mentioned conventional problems, and aims to provide a blood circulation device that has high dialysis efficiency and can shorten the time required for dialysis. be.

(Means for Solving the Problems) The blood circulation device in the blood circuit of the hemodialysis apparatus of the present invention performs hemodialysis by interposing a dialyzer 3 in the middle of the blood circuit 5 that circulates the blood of a living body extracorporeally. In the hemodialysis apparatus, a sealed container 18 is provided on the upstream side of the dialyzer 3 in the blood circuit 5.
A blood tank 22 is provided, the inside of which is divided into a blood chamber a connected to the blood circuit 5 with the diaphragm 19 as a boundary and storing blood, and an air chamber b having air pressure adjustment means. On the downstream side, an on-off valve 3 for controlling blood flow
3, and a detector for detecting that a certain amount of blood has accumulated in the blood tank 22, and a control device 14 for opening the on-off valve 33 based on a detection signal from the detector 23. This is what happens.

(Example) Hereinafter, the present invention will be described by way of an example with reference to the drawings.

FIG. 1 shows an embodiment of the dialysis apparatus of the present invention in a positive pressure method. In the figure, 1a and 1b are cannulae, 2 is a blood pump, 3 is a dialyzer, 5 is a tube, 8a and 8b are dialysate supply or discharge channels, 10 is a pressure measuring device, 11 is a storage device, and 12
13 is a blood flow control device, 13 is a filter device, and 14 is an electric control device for controlling these devices. In addition to these, an infusion needle and a heparin injector are connected to the blood circuit of the dialysis machine, but these are not shown.

Referring also to FIGS. 2 and 3, the pressure measuring device 10 measures the pressure of blood on the upstream side of the blood pump 2 without contacting with air, and includes a capsule-shaped pressure transducer 15. , a pressure sensor 16 and a syringe 17 connected thereto. The pressure transducer 15 has a sealed container 18 with a diaphragm 19 separating the blood chamber a and the air chamber b.
The container 18 has an inlet 20a and an outlet 20b communicating with the blood chamber a.
Two connection ports 20c and 20d communicating with air chamber b
is provided. Inlet 20a and outlet 20
Tubes 5a and 5b are connected to b, so that blood flows in blood chamber a, and connection port 2
0c is a pressure sensor 16 by a tube 16a.
The connection ports 20d are respectively connected to the syringes 17 by tubes 17a, and the amount of air in the air chamber b is increased or decreased by pumping the syringes 17 to adjust the amount of deformation of the diaphragm 19 and to control the pressure. Measured by pressure sensor 16. A clamp 21 for clamping and closing the tube 17a is attached to the tube 17a, and this clamp 21 is removed when the syringe 17 is operated.

The pressure sensor 16 has the same function as the pressure sensor described in Japanese Unexamined Patent Application Publication No. 181162/1987, which was previously proposed by the inventor of the present invention, and for details, please refer to that publication. Here I will explain the outline. While the blood pump 2 is operating and normal dialysis is being performed, the blood in the blood chamber a has an almost constant negative pressure, but if excessive water removal is performed, the negative pressure increases further. Also, if the tip of the cannula 1a sticks to the inner wall of the blood vessel and the blood becomes occluded, an even greater negative pressure will be generated.
The pressure detector 16 can be set to detect these negative pressures in two stages and output a signal, and can also read the pressure visually. That is, the container 18 is made up of two half-split container members 18a, 18a facing each other, each having the same shape.
A diaphragm 19 having the same outer periphery is sandwiched between b and 18b, and these are welded and brought into close contact with each other. The container member 18a is integrally molded using a polymeric material such as vinyl chloride, hard vinyl chloride, polycarbonate, or silicone rubber. The diaphragm 19 has appropriate elasticity,
The same material as the container member 18a is used to facilitate welding. It is convenient to make the container member 18a or the diaphragm 19 transparent so that the internal state can be monitored.

The storage device 11 includes a blood tank 22 that can store blood and apply pressure to the blood, a pressure sensor 23 and a syringe 24 connected to the blood tank 22 . The blood tank 22 has the same structure as the pressure transducer 15 described above, and its shape is large enough to store the required amount of blood. That is, in FIG. 4, the inside of the container 18 is divided into a blood chamber a and an air chamber b by a diaphragm 19, and blood flows into the blood chamber a from the tube 5c and is stored there. If a flow path is formed at the rear of the blood circuit, the blood in the blood chamber a will flow out from the tube 5d. The blood in the blood chamber a is pressed by the air pressure that increases or decreases the amount of air in the air chamber b by pumping the syringe 24, and the pressure in the air chamber b is measured by the pressure sensor 23.
This is used to measure the amount of blood that has accumulated. The pressure sensor 23 can be the same as the pressure sensor 16 described above, but it needs to be able to detect positive pressure in a wider range. The pressure detector 23 outputs a signal when the amount of blood stored in the blood chamber a of the blood tank 22 becomes more than a certain amount or less than a certain amount. Note that the clamp 25 is similar to the clamp 21 described above.

The blood control device 12 is shown in FIG.
The downstream side of the dialyzer 3 is interposed between the tubes 5e and 5f, and branches into a pressure conversion channel 32a passing through the pressure converter 26 and a bypass channel 32b having a bypass valve 33. A pressure sensor 27 and a syringe 28 are connected to the pressure transducer 26. This pressure transducer 26 is similar to the pressure transducer 1 described above.
One of the container members of No. 5 has a flat shape, that is, the container 30 has a flat container member 30.
A and a curved container member 30b, and the diaphragm 19 is arranged to substantially follow the inner surface of the container member 30a in a free state. A bypass section 29 consisting of the bypass flow path 32b and a bypass valve 33 is provided between the connection ports 31a and 31b through which blood flows in or out. By opening and closing the bypass valve 33, the bypass flow path 32b are now in circulation or blocked. The bypass valve 33 is electromagnetically operated, and may have a structure in which, for example, the bypass passage 32 made of a flexible tube is pinched and compressed from the outside by the operation of a solenoid.
When an appropriate amount of air is fed into the air chamber b of the pressure transducer 26 to maintain a constant pressure, the tube 5
Unless the pressure of the blood from e is higher than that, it cannot flow into the blood chamber a from the connection port 31a, and no blood flows into the pressure conversion channel 32a.
Therefore, when the bypass valve 33 is closed, when blood is flowing, a constant pressure will be generated regardless of the flow rate, so it cannot be used as a positive pressure generator in the normal positive pressure method. It can also be used as a safety valve that allows blood to flow when it exceeds a certain pressure.

The filter device 13 is for removing air and foreign matter such as small blood clots that may be mixed into the blood. Its structure is shown in FIG. 6, and the filter container 34 is connected to the pressure transducer 15 described above. container 18
This is the same as , except that only the diaphragm 19 is replaced with a filter element 37 of a suitable mesh. Connection ports 38a, 38 located in opposite positions
Tubes 5f, 5g are connected to d to allow blood to flow through the filter element 37, and syringes 35, 36 are connected to the other ports 38b, 38c via tubes 35a, 36a.
are connected, and these tubes 35a, 36
A is clamped with clamps 39 and 40.
Therefore, the filter container 34 is removed from the connection port 38a.
The blood that has flowed into the chamber is filtered by the filter element 37 and flows out from the connection port 38d, but if air is mixed in the blood, an air reservoir 4 is formed above.
1 and accumulates, so the air may be removed from the connection port 38c using the syringe 36 from time to time. Further, foreign substances such as small blood clots that are blocked by the filter element 37 are removed from the connection port 38 by the syringe 35.
Just take it out from b. This filter 37
, the connection port 38d should be in an attitude that does not point upward.

Although not shown, the dialysate supply path 8a and discharge path 8b of the dialysis machine 3 are connected to piping lines and valves for supplying and discharging the dialysate, a lightweight device for measuring the amount of water removed, etc. has been done. The dialysate can be supplied by continuously flowing the dialysate at a rate of approximately 500 ml/min into the dialyzer 3, or by supplying an amount of dialysate approximately equal to the priming amount of dialysate in the dialyzer 3 by several tenths of a kilogram/min.
There is a method of applying pressure to about cm ² to 1 Kg/cm ² and flowing at a high flow rate for a short period of time, and doing this intermittently.
For details on the latter method, refer to the specification of Japanese Patent Application No. 1982-212895, which was previously proposed by the inventor of the present invention.

The electric control device 14 controls the dialysis machine and is composed of relays, semiconductor hard logic, soft logic using a microcomputer, or a combination thereof.
The bypass valve 33 is opened or closed according to the upper or lower limit signal of the pressure from the pressure sensor 16, and the blood pump 2 is stopped or the dialysate is stopped according to the lower limit signal of the pressure (negative pressure) from the pressure sensor 16. The supply is also stopped and an alarm is issued, but more detailed control details will be made clear by the operation of the dialysis apparatus, which will be explained next.

First, in the preparation stage, physiological saline is sufficiently distributed in the blood circuit connected by tube 5, and air is removed from the blood circuit by using the air bleed device of each device or by shaking each device. After that, blood is introduced.
Next, the detected pressure of the pressure detector 16 of the pressure measuring device 10 is set. To do this, the resting shunt pressure _P1 is measured by the pressure detector 16 while the blood pump 2 is stopped. P ₁ is a positive pressure, usually several tens of mmHg. Next, rotate blood pump 2,
At this time, the pressure sensor 16 measures the shunt pressure P ₂ during circulation. P ₂ is cannula 1 from P ₁
This is the value obtained by subtracting the pressure drop due to a, and is usually a negative pressure. The first set pressure P ₃ of the pressure detector 16 is set to P ₂ −
Set the _second set pressure _P4 to _P3 − (50 to 100)
Set to . Therefore, P ₃ is lower than the circulating shunt pressure P ₂ by the static shunt pressure P ₁ , and P ₄ is 50 to 100 mmHg lower than P ₃ .
It will be a low value. At this time, the amount of air in the air chamber b is adjusted using the syringe 17 so that the amount of deformation of the diaphragm 19 is as small as possible.

Next, the pressure in the air chamber b of the pressure transducer 26 of the blood flow control device 12 is set appropriately high so that blood flows through the pressure conversion channel 32a under normal conditions. Air is sent into the air chamber b of the blood tank 22 of the storage device 11 by the syringe 24, and the pressure sensor 23 is set so that the pre-pressure is above a certain level when no blood is stored in the blood tank 22.
Adjust while watching. This preload force is provided so that when blood is discharged from the blood tank 22, the blood flows at a sufficient flow rate against the circuit resistance of the dialyzer 3 and downstream thereof. When the bypass valve 33 is closed, blood begins to accumulate in the blood tank 22 due to the constriction effect in the pressure conversion flow path 32a, and as a result, the pressure in the air chamber of the blood tank 22 increases, so that the blood flows into the blood tank 22. The pressure sensor 23 is set so that a signal indicating the upper limit of the pressure is output when a certain amount is stored in the pressure sensor 23. This signal opens the bypass valve 33, and the stored blood is released in a short time under pressure and flows into the dialyzer 3 at a high flow rate, destroying the membrane on the blood side of the dialyzer 3. This results in a decrease in film resistance. When most of the blood in the blood tank 22 has been discharged, a signal indicating the lower limit of the pressure from the pressure detector 23 is output. Blood begins to accumulate again. During this time, the blood in the dialyzer 3 is pressurized by the pressure from the blood tank 22, and dialysis is performed by the movement of substances and water within the dialyzer 3. The amount of blood stored in the blood tank 22 may be set to be equal to or half the priming amount of blood in the dialyzer 3, for example, 80 to 100 ml. There is no problem even if this amount of blood flows into the body in a short period of time. However, since the amount of blood that can normally flow out of the body is 150 to 200 ml/min,
Storage and discharge will be repeated at a rate of 2 to 3 times per minute. Compared to the conventional case in which blood was continuously flowed at a constant flow rate, the dialysis efficiency was improved by 20 to 25% in the above embodiment. In addition,
Although the blood pump 2 continues to operate while blood is being discharged from the blood tank 22, it may be stopped during this period. In addition, if dialysate is also supplied intermittently, the relationship between the tamping of dialysate supply and the timing of blood discharge should be done at the same time or with a certain time lag between them. It is conceivable to do it independently of each other, etc. For example, when the pressure detector 16 outputs a detection signal, the blood pump 2 may be stopped and the blood in the blood tank 22 may be discharged.

Note that the pressure in the air chamber b of the pressure converter 26 is set high, and the blood tank 22 is connected to the pressure conversion channel 32a.
It is also possible to use it as a safety valve in which blood does not flow at all times during the blood storage process and only flows when abnormal pressure occurs.

In the above-mentioned embodiment, in addition to the effect of improving dialysis efficiency compared to conventional devices, the blood circuit is a closed circuit and there is almost no contact between blood and air, so blood coagulation is less likely to occur. It has an excellent effect, and as a result, the amount of anticoagulants such as heparin used can be significantly reduced, and a relatively large amount of blood can be stored in the blood tank 22 for a long time. There is an advantage. Also,
The risk of bacterial infection is drastically reduced, and since the blood chamber a is filled with blood, there is no risk of the air in the air chamber getting mixed into the blood circuit such as the tube 5, which was the case in the past. The amount of air can be easily adjusted, and blood will not flow into the pressure gauges 16 and 23, making them unusable. Moreover, since the pressure transducer 15 and the blood tank 22 can be used in any position, the tube 5 can be made to the shortest length, and the amount of extracorporeally circulating blood can be reduced accordingly. It has the advantage of being extremely convenient to handle and suitable for portable use.

FIG. 7 shows another embodiment of the dialysis apparatus of the present invention. This is a device that is almost the same as that shown in Fig. 1 applied to single-needle dialysis.
The flow path of blood flowing out from the filter container 34 is as follows:
The tube 5g is branched and connected to the same cannula 1a as the tube 5a on the inflow side. In this dialysis device, the blood pump 2 is stopped while blood is discharged from the pressure tank 22, and the tube 5
It is necessary to ensure that blood flows in from tube a and flows out from tube 5g alternately. In the conventional single-needle dialysis method, an air chamber was used as a blood tank and connected between the dialyzer and the bypass section 29, so the amount of blood that could be stored was small, and it was necessary to add it for discharge. The pressure that can be generated is low, and it takes almost the same amount of time to draw blood out of the body and introduce it, and because the flow rate inside the dialyzer 3 is not fast, it is easy to form a membrane, and the conventional multi-needle Although the dialysis efficiency was only about 60% compared to the dialysis method (for example, the one shown in Figure 10), the single-needle dialysis equipment of this example was the same as the dialysis equipment shown in Figure 1. As a result, the dialysis efficiency can be approximately twice that of the conventional single needle dialysis method.

FIG. 8 shows still another embodiment of the dialysis apparatus of the present invention, which is applied to a negative pressure method, in which the blood flow control device 12 shown in FIG.
1 and the dialyzer 3, and
A throttle valve and a dialysate pump are connected to the supply path 8a and the discharge path 8b, respectively, so that the dialysate inside the dialyzer 3 has a negative pressure. The operation and effects of this dialysis apparatus are substantially the same as those explained in FIG. 1, so the explanation will be omitted.

Examples of the present invention are not limited to these, but include:
For example, the pressure measurement device 10 may be omitted, or the pressure conversion channel 32 of the blood flow control device 12 may be omitted.
It is also possible to omit a.

FIG. 9 shows another embodiment of the pressure transducer 15 or the blood tank 22, in which the containers 42 are arranged in four identically shaped containers.
Container members 42a... are placed facing each other, and the respective flange portions 42b are welded with the diaphragm 19 in between.
d are in a straight line, making it easy to connect the tubes and facilitate blood flow.

In each of the embodiments described above, the pressure detectors 16, 23,
Although a bourdon tube type indicator needle and an upper and lower limit setting needle are used as the 27, it may be a combination of a strain gauge type or semiconductor type sensor and a suitable setting display device. Other suitable pumps may be used in place of syringe 23. Pressure detector 16, 2
3, 27 and the syringe 23 may be branched and connected from one connection port, and in that case, the other connection port is unnecessary and may be plugged with a blind stopper.

(Effects) According to the blood circulation device of the present invention, in the hemodialysis process, blood is stored in the blood tank located upstream of the dialyzer by closing the on-off valve on the downstream side of the dialyzer, and the blood is stored in the blood tank located upstream of the dialyzer. By opening the on-off valve when the storage amount reaches a certain amount, the blood in the blood tank flows into the dialyzer in a short time due to the air pressure applied through the diaphragm and reaches the surface of the dialysis membrane. Because turbulent flow is generated and membrane resistance is reduced, and hemodialysis continues during the repeated storage and discharge of the blood tank, dialysis efficiency is significantly improved.
The time required for dialysis is reduced. Moreover, in the above device, negative pressure is applied to the blood stored in the blood tank via the diaphragm, and the blood circuit becomes a closed circuit that hardly comes into contact with air, so that air in the chamber does not get mixed in like in a conventional air chamber. Since there is no risk of blood clotting due to contact with the air, the amount of anticoagulants such as heparin used can be significantly reduced, and a relatively large amount of blood can be stored in the blood tank for a long time. This has the advantage of dramatically reducing the risk of bacterial infection.

Furthermore, the device of the present invention can be used in conventional positive pressure method, negative pressure method, single needle dialysis method, multineedle dialysis method, and other dialysis methods, and especially when applied to single needle dialysis method, Dialysis efficiency has been significantly improved, making it possible to take full advantage of the superior advantages of this method in that only one cannula is required, reducing the time, labor and expense required for dialysis, and increasing safety. becomes.

[Brief explanation of the drawing]

FIG. 1 is a diagram of a dialysis apparatus showing an embodiment of the present invention;
Fig. 2 is an enlarged sectional view of the pressure measuring device, Fig. 3 is a plan view of the pressure transducer shown in Fig. 2, Fig. 4 is an enlarged sectional view of the storage device, and Fig. 5 is an enlarged sectional view of the pressure transducer shown in Fig. 2. FIG. 6 is an enlarged cross-sectional view of the flow control device, FIG. 6 is an enlarged cross-sectional view of the filter device, FIGS. 7 and 8 are views showing a dialysis apparatus according to another embodiment of the present invention, and FIG. The figure is a sectional view showing another embodiment of a pressure transducer and a blood tank, FIG. 10 is a view showing an example of a conventional dialysis device, and FIG. 11 is a view showing the principle of dialysis. 1a, 1b... cannula, 2... blood pump, 3... dialyzer, 5... tube (blood circuit),
11... Storage device, 14... Electric control device (control device), 18... Container, 19... Diaphragm,
20a...Inflow port, 20b...Outflow port, 20c,
20d... Connection port, 22... Blood tank, 23...
...Pressure detector (detector), 33...Bypass valve (on/off valve), a...Blood chamber, b...Air chamber.

Claims (1)

[Claims] 1. In a hemodialysis device that performs hemodialysis by interposing a dialyzer in the middle of a blood circuit that circulates the blood of a living body extracorporeally, a diaphragm is installed inside a sealed container on the upstream side of the dialyzer in the blood circuit. A blood tank is provided which is divided into a blood chamber that is connected to the blood circuit and stores blood, and an air chamber that has an air pressure adjustment means, and the flow of blood is controlled downstream of the blood tank. a detector that detects that a certain amount of blood has accumulated in the blood tank; and a control device that controls opening of the on-off valve based on a detection signal from the detector. A blood circulation device in a blood circuit of a hemodialysis device.