JPH0468951B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automatic control device for an ultrafiltration pressure value that determines a unit precipitation amount in a precipitation control operation in hemodialysis.

(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. The main function of the kidneys is to produce urine, and most of this urine is water, so in hemodialysis it is important to remove water from the blood, so-called water removal. It becomes a challenge. Water in the body moves into the blood via intracellular, intercellular, and blood vessels, and it is necessary to remove water at a rate commensurate with this transfer rate.

Recently, however, dialysis membranes used in dialyzers have been improved, and the membrane thickness has become extremely thin, and at the same time, the filtration pores on the membrane surface have become larger, improving the efficiency of removing medium to large molecular weight wastes. This also greatly improves the ultrafiltration coefficient (UFR), which may cause the patient to experience a drop in blood pressure due to the rate at which water is removed during dialysis. In order to stop water removal as a treatment in this case or as a normal temporary stop operation, in the positive pressure method, the restriction of the restrictor in the blood circuit is released.

Now, the blood that comes out of the dialyzer returns to the patient's venous blood vessels, but in many patients, there are complex factors such as changes in the shunt of the blood vessel, deformation due to long-term puncture of the cannula, and lesions due to the underlying disease.
There are various problems in the vascular lumen, which increases venous vascular resistance, and when dialyzed blood returns to the venous blood vessel, a resistance force proportional to the amount of blood returned (generally called natural venous pressure) is applied. It is supposed to occur in venous blood vessels. Therefore, even when the above-mentioned operation to stop water removal is performed, this natural venous pressure is applied to the dialyzer as residual pressure, and in reality, a considerable amount of water is removed. For example, 150-200
Blood volume in ml/min (extracorporeally circulating blood volume during normal dialysis)
30-120mmHg depending on the patient, rarely 200mmHg
A natural venous pressure of more than
When using a mmHg/hr dialyzer, 120~
Excessive body fluid removal of 480ml/hr.

In this way, conventionally, even when water removal is stopped, a considerable amount of water is being removed, so the nurse must replenish the patient with replacement fluid commensurate with the amount of water removed while water removal is stopped. This work requires a lot of effort, such as having to be busy with frequent blood pressure measurements, and most of the work relies on experience and knowledge, which is critical to the safety of patients undergoing dialysis. Currently, there are still problems.

(Problem to be Solved by the Invention) This is because even when the above-mentioned operation to stop water removal is performed, natural venous pressure still occurs in the venous blood vessels from which a considerable amount of water is removed. Therefore, the present invention measures the natural venous pressure, and uses this natural venous pressure as a reference to feedback control the pressurization value on the blood circuit side and the pressurization value on the dialysate side, thereby achieving the desired limit. The purpose is to obtain an external filtration pressure value, thereby making it possible to automatically stop water removal and control the water removal speed.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a pressurizing device 10 that sets the pressure on the downstream side of the dialyzer 3 in the blood circuit 9, and A natural venous pressure detection device 19 that detects the natural venous pressure value propagated to the blood circuit 9 on the downstream side.
, a pressurizing device 8 that sets the pressure on the downstream side of the dialyzer 3 in the dialysing fluid circuit 7, an ultrafiltration pressure value setting means 28 that presets an ultrafiltration pressure value, the detection device 19, and both of the above. The ultrafiltration pressure setting means 2 reads the respective pressure values of the pressurizing devices 10 and 8.
8, the detection device 19 and the automatic control means 27 automatically control the pressure devices 10 and 8 so as to reach the set ultrafiltration pressure value set by the pressure control device 8.

In addition, in this embodiment, the pressurization value on the downstream side of the dialyzer 3 in the blood circuit 9, the above-mentioned natural venous pressure value, the pressurization value on the downstream side of the dialyzer 3 in the dialysate circuit 7, and these pressure values. This configuration includes a display section 29 for respectively displaying the ultrafiltration pressure value and the set ultrafiltration pressure value calculated by comparison calculation.

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

FIG. 1 shows an embodiment of a positive pressure method of a dialysis machine. In the figure, 1a and 1b are cannulae, 2 is a blood pump, 3 is a dialyzer, 4 is a tube, and cannula 1a is punctured into human body A.
The blood flowing out from the tube 4a passes through the tube 4b and is sent into the dialyzer 3.
It flows out from c. The dialyzer 3 is connected to a dialysate intake path 5 and a discharge path 6. A pump P is provided in the supply path 5, and a pressurizing device 8, which will be described later, is provided in the discharge path 6, that is, on the downstream side of the dialyzer 3 in the dialysate circuit 7. Therefore, the dialysate is sent to the dialyzer 3 from the supply path 5 by the pump P,
The dialysate in the dialyzer 3 is discharged from a discharge path 6 via a pressurizing device 8 to a drainage tank or the like as indicated by an arrow. On the other hand, blood that has flowed into the dialyzer 3 and has been dialyzed flows out from the tube 4c, that is, the dialyzer 3 in the blood circuit 9.
A pressurizing device 10 is also provided on the downstream side of the body A, and the blood is returned to the human body A by the cannula 1b via the pressurizing device 10 and the tube 4d.

The pressurizing device 8 or 10 used in the present invention preferably has the structure shown in FIGS. 2a and 2b. That is, in the pressurizing devices 8 and 10, the inside of a sealed container 11 is divided by a diaphragm 11a into two chambers: a liquid chamber a through which dialysate and blood flow and an air chamber b through which pressurized air flows in and out. , container 11
has an inlet 12a and an outlet 1 communicating with the liquid chamber a.
2b, one connection port 13 communicating with the air chamber b is provided. The container 11 is a flat container member 11
A diaphragm 11a having the same outer circumference is sandwiched between the brim portions of the container members 11b and 11c, and these are adhered to each other so that the diaphragm 11a is free. In this state, it almost follows the inner surface of the flat container member 11b. The container members 11b and 11c are
It is made of a relatively hard polymeric material such as vinyl chloride, polycarbonate, or silicone rubber, and is integrally molded. The diaphragm 11a has appropriate elasticity and is made of the same material as the container members 11b and 11c to facilitate welding. It is convenient to make the container members 11b, 11c and the diaphragm 11a transparent so that the internal state can be monitored.

Referring also to FIG.
4, pressure gauges 17 and 18 are installed to measure the pressurization value on the dialysate circuit side and the pressurization value on the blood circuit side, respectively.
is provided.

Then, the air chamber b of the pressurizing device 8 is pressurized by the air pump 15 to adjust the amount of deformation of the diaphragm 11a, and the pressure gauge 17 is adjusted according to this adjusted pressure.
The measuring needle moves and the adjusted pressure is measured by the pressure gauge 17.
It is now possible to read from Note that the air pumps 15 and 16 are syringes with needles removed, but are of course not limited to this, and may be well-known pumps such as rotary pumps. As is clear from the above description, the pressure gauges 17 and 18 are operated by air pressure, such as a Bourdon tube, a bellows, or a diaphragm pressure gauge. It is output as a detection signal converted into .

Further, in the blood circuit 9, a natural vein detection device 19 is interposed further downstream of the pressurizing device 10. This detection device 19 has a configuration similar to that of the pressure devices 8 and 10, but there are some differences, so
To explain this with reference to FIG. 3, the detection device 1
9 has a diaphragm 19 inside the sealed container 20.
A is divided into two blood chambers A and an air chamber B, and the blood chamber A is provided with an inlet 21 and an outlet 22 from the blood circuit 9, and the air chamber B is provided with an inlet 21 and an outlet 22 from the blood circuit 9.
A connection port 24 with a pressure monitor tube 23 is provided in the holder. The container 20 consists of a pair of curved container members 20a, 20b.
A diaphragm 19a having the same outer circumference is welded to each other between each of the brim portions of the container member 0b, so that the diaphragm 19a is positioned in the middle of the pair of container members 20a and 20b in a free state. It's getting old. The container members 20a and 20b are made of a relatively hard polymeric material, the diaphragm 19a is made of a material having appropriate elasticity, and in order to facilitate welding, both are made of the same material.
In addition, as with the pressurizing devices 8 and 10, it is preferable that the pressurizing devices are made of a transparent material so that the inside can be monitored. Naturally, this detection device 19 is also connected to a pressure gauge 25 having the same structure as described above, which measures the natural venous pressure value through a pressure monitor tube 23.

Next, to explain how to use the dialysis machine configured as described above, in Fig. 1,
When setting to perform a normal large amount of water removal, on the dialysate circuit side, the dialysate is supplied to the dialyzer 3 from the supply path 5 by the pump P, and the dialysate in the dialyzer 3 is is discharged to the outside from the discharge path 6 via the pressurizing device 8. On the other hand, on the blood circuit side, the blood flowing out from the human body A is sent to the dialyzer 3 by the blood pump 2, where it is removed. The water (dialysis) blood is passed through the pressurizing device 10 to the human body A.
However, in this case, in order to remove a relatively large amount of water in general, the pressurizing device 1 on the blood circuit side must be
It is sufficient to apply a pressure equal to or higher than the patient's natural venous pressure to zero, and to set the pressurizing device 8 on the dialysate circuit side to zero pressure, that is, to an open state.

That is, the detection device 1 provided on the downstream side of the pressurizing device 10
9 read the natural vein value with the pressure gauge 25,
The air chamber b is pressurized by the air pump 16, and the pressure value set to the natural vein value or higher is read by the pressure gauge 18. Similarly, the pressure in the air chamber b in the pressurizing device 8 on the dialysate circuit side is read and set to zero using the pressure gauge 17.

Through the above operations, the blood chamber a of the pressurizing device 10 is
(Fig. 2) is pressurized via the diaphragm 11a, so the blood passes through the blood chamber a while pushing back the diaphragm 11a by a pressure greater than this applied pressure. The pressurizing force of the blood circuit pressurizing device 10 is directly applied to the blood circuit side, and this pressure becomes the ultrafiltration pressure applied to the dialysis membrane surface in the dialyzer 3.
Water will be removed in proportion to this pressure.

Next, a case will be described in which water is removed within the range of natural venous pressure. As mentioned in the prior art section, the human body is always loaded with natural venous pressure, and even if an operation is performed to stop water removal, a considerable amount of water will actually be removed due to natural venous pressure. be.

Figure 4 shows that the effective ultrafiltration coefficient (UFR) is 4.
This is a graph showing the relationship between the venous pressure (ultrafiltration pressure) generated on the dialysis membrane surface and the ultrafiltration amount (precipitation amount) when using a dialysis machine with ml/mmHg/hr.
For example, the natural venous pressure measured with a pressure gauge 25 is 140 mm
If Hg is used, an excessive amount of body fluid of 560 ml/hr will be deposited.

Depending on the patient, it may be necessary to remove water in small amounts due to weakened physical strength. In some cases, the amount of precipitation is adjusted to be within the amount of precipitation due to natural venous pressure by adjusting the load to avoid placing an excessive burden on the patient.

In this operation, first, the pressure in the air chamber b of the blood circuit side pressurizing device 10 is set to zero while being read by the pressure gauge 18. Therefore, in this state, the blood circuit 9 is loaded with the natural venous pressure (for example, 140 mmHg) measured by the pressure gauge 25 of the detection device 19. Next, the dialysate circuit pressurizing device 8
The air chamber b is pressurized by the air pump 15 to apply pressure to the dialysate chamber a (Fig. 2), and the pressure is increased so that, for example, a pressure of 30 mmHg is applied to the membrane surface inside the dialyzer. It is controlled and set while reading by a total of 17. Through this operation, the membrane surface of the dialyzer 3 has a difference between natural venous pressure (140 mmHg) - dialysate pressure (30 mm Hg).
When a differential pressure of 110 mmHg (Hg) = 110 mmHg is applied as ultrafiltration pressure and the effective UFR of this dialysis membrane is 4 ml/mmHg/hr, the natural venous pressure (140
440 lower than the amount of water removed (560ml/hr) by mmHg)
It can be seen that the amount of water removed is ml/hr.

Furthermore, a case in which a setting is made to stop precipitation will be explained. In this operation, first, adjust the pressure gauge 1 so that the pressurizing force in the air chamber b of the blood circuit side pressurizing device 10 becomes zero.
Set by air pump 16 while reading by 8. In this state, the dialyzer 3 is loaded with the natural venous pressure read by the pressure gauge 25. Next, the air chamber b of the dialysate circuit side pressurizing device 8
By applying pressure with the air pump 15, the dialysate chamber a is pressurized via the diaphragm 11a (FIG. 2), thereby reducing the dialysate circuit until it passes through the pressurizing device 8. Adjust the dialysate pressure in the dialyzer 7 to the natural venous pressure, for example 140 mmHg, while reading the pressure gauge 17. By this operation, no differential pressure, that is, ultrafiltration pressure is applied to the membrane surface within the dialyzer 3, and therefore water removal is not performed and the water removal is stopped.

From the above explanation, the following can be concluded. That is, in the positive pressure water removal method, the pressure value P ₁ displayed on the pressure gauge 18 of the blood circuit side pressurization device 10
is higher than the pressure value P ₂ displayed on the pressure gauge 25 of the natural venous pressure detection device 19, the pressure value displayed on the pressure gauge 18 of the blood circuit side pressurization device 10
The ultrafiltration pressure value P is obtained by subtracting the pressure value _P3 displayed on the pressure gauge 17 of the dialysate circuit side pressure device 8 from _P1 . Conversely, the pressure value _P1 displayed on the pressure gauge 18 of the blood circuit side pressurization device 10 is the pressure value displayed on the pressure gauge 25 of the natural venous pressure detection device 19.
Natural venous pressure detection device 19 when lower than P ₂
The ultrafiltration pressure P is obtained by subtracting the pressure value P3 displayed on the pressure gauge ₁₇ of the dialysate circuit side pressurizing device ₈ from the pressure value P2 displayed on the pressure gauge 25.

In the present invention, the dialysis control device is equipped with a control means in which the operation sequence based on the above conclusion is stored as a computer program, and the above pressurization value is feedback-controlled based on this command, and the set ultrafiltration pressure value is controlled. In addition to automatically obtaining the pressure values, these pressure values are also displayed on the display section as appropriate.

That is, in FIG.
are connected to drive motors M ₂ and M ₁ such as servo motors and step motors that drive them respectively.
The drive signals for controlling these drive motors M ₂ and M ₁ and the pressure signals from the pressure gauges 18, 17, and 25 that measure the pressurized values P ₁ and P ₃ and the detected pressure value P ₂ are A. The data is input to and output from the interface 26 via a D/D converter or a D/A converter, and information is exchanged with the control device 27 here. The control device 27 stores an operating procedure based on the above-mentioned conclusion as a program, and inputs it via the interface 26 based on the stored program in accordance with a command from a command device 28 such as a keyboard. Pressure gauge 17,1
By processing the pressure signals P ₁ to _{P 3} of 8 and 25 and driving the drive motors M ₁ and M ₂ , it is controlled so that the dialysis work can be performed at the set ultrafiltration pressure value. , the control device 27 has a display device 29
are connected, and each pressure value is displayed on this.

FIG. 5 shows the display device 29, which displays the initial ultrafiltration pressure value based on the signal input from the control device 27.
The ultrafiltration pressure display section 30 displays the change from P ₀ to the desired set value moment by moment, and the set ultrafiltration pressure displays the ultrafiltration pressure value Ps of the desired set value commanded by the command unit 28. A display unit 31 , a blood circuit side pressurization value display unit 32 that displays the pressurization value P ₁ downstream of the dialyzer 3 in the blood circuit 4 , a natural venous pressure value display unit 32 that displays the natural venous pressure value P ₂ propagated to the blood circuit 4 A venous pressure display section 33 and a dialysate circuit side pressurization value display section 34 that display a pressurization value P ₃ on the downstream side of the dialyzer 3 in the dialysate circuit 7 are provided.

FIG. 6 is a flowchart showing the operating functions of the control device 27, and the functions based on the above-mentioned conclusions are stored as a program.

First, the command unit 2 starts to perform the normal large amount of water removal.
The case where the ultrafiltration pressure value Ps is set by the command No. 8 will be explained.

The reading function 35 reads the above set ultrafiltration pressure values Ps from the interface 26, each pressure value P ₁ , P ₂ ,
P ₂ is read and the display function 36 calculates and processes these values to obtain the initial ultrafiltration pressure value.
Po, set ultrafiltration pressure value P ₃ , and each pressure value P ₁ , P ₂ ,
P ₃ is displayed on the display device 29. On the other hand, as determined by the judgment function 37, the set value Ps is the natural venous pressure.
If it is larger than P ₂ , that is, if a large amount of water is normally removed, the process moves to the judgment function 38, and it is judged whether or not the dialysate circuit side pressurization value P ₃ is zero, and if it is not zero, P ₃ signal is D/A converted by the D/A converter 39 to operate the servo device 40 that drives the dialysate circuit side drive motor _M2 until _P3 becomes zero.
Return to connector L and repeat this operation. When the dialysate circuit side pressurization value _P3 becomes zero by the servo device 40, the judgment function 41 determines whether the blood circuit side pressurization value _P1 is equal to the set value Ps, and if they are not equal, The differential pressure _P4 between _P1 and Ps is determined by the calculation function 42, and the differential pressure signal _P4 is D/A converted by the D/A converter 43 to drive the blood circuit side drive motor _M1. The servo device 44 is operated to return to the connector L and repeat this operation until P ₄ becomes zero. When the differential pressure _P4 becomes zero, the ultrafiltration pressure value Po matches the set value Ps and also matches the blood circuit side pressurization value _P1 , and the judgment function 41 determines that the control is complete. After checking, the calculation function 45 determines that the ultrafiltration pressure value P ₀ matches the set filtration pressure value Ps, that is,
It is replaced with Po=P ₁ and displayed on the display device 29. That is, the control device 27 constantly monitors the above-mentioned pressure values, such as the natural venous pressure value, which may change even during dialysis work, and adjusts the ultrafiltration pressure value during dialysis work.
If Po deviates from the above-mentioned set ultrafiltration pressure value Ps,
The control function described above operates to compensate and always maintain the set value.
Feedback control is performed so that the ultrafiltration pressure value Po is equal to Ps.

Next, a case will be described in which the ultrafiltration pressure value Ps is set by a command to the command unit 28 to remove water within the range of natural venous pressure. In this case, since the set ultrafiltration pressure value PS is not greater than the natural venous pressure value _P2 , the judgment function 37 makes a judgment and the process moves to the judgment function 46, where the blood circuit side pressurization value _P1 is zero. Determine whether or not, and if P ₁ is not zero, P ₁
The signal is D/A converted by a D/A converter 47,
The servo device 44 that drives the blood circuit side drive motor _M1 is operated until _P1 becomes zero.
Return to and repeat this action. When the blood circuit side pressurization value P ₁ becomes zero by the servo device 44, the differential pressure P ₇ =P between the natural venous pressure value P ₂ and the dialysate circuit side pressurization value P ₃ is determined by the calculation function 48. Function 49 determines ₂ −P ₃ and determines whether this differential pressure P ₇ is equal to the set value Ps.
If they are not equal, the calculation function 50 calculates the differential pressure P ₈ = P ₇ - Ps, and the D/A converter 51 converts _this differential pressure signal P ₈ into a D/A converter 51.
The servo device 40 that drives the dialysis circuit side drive motor _M2 is operated until _P8 becomes zero.
Return to connector L and repeat this operation. Differential pressure P ₈
If becomes zero, the ultrafiltration pressure value _P7 matches the set value Ps, and the judgment function 49 confirms that the control has been completed, and the calculation function 52 determines whether the ultrafiltration pressure during dialysis It is displayed on the display device 29 that the filtration pressure value Po matches the set value Ps, that is, it is replaced with Po= _P7 . In this way, when the ultrafiltration pressure value Po during dialysis work deviates from the set ultrafiltration pressure value Ps, the control device 27 controls the drive motor M so that the ultrafiltration pressure value Po is always equal to the set value Ps. ₁ and _M2 for feedback control. Note that when the aforementioned air pumps 15 and 16 are piston type, the servo devices 40 and 44 are position controlled,
When it is a rotary type, it is a rotation control, and the feedback 40a, 44a corresponding to each control is used as a position or rotation speed feedback, and it is designed to stabilize and improve the precision of the servo devices 40, 44. Adder 40
b, 44b and amplifiers 40c, 44c are of course well known.

In addition, if water removal is stopped, the set ultrafiltration pressure value
By setting Ps to a value lower than and close to the natural venous pressure value _P2 , it is possible to achieve almost the same effect as stopping water removal, and
When a complete stop is expected, that is, the set ultrafiltration pressure value
When Ps is equal to the natural venous pressure value _P2 , it is possible to feedback-control the two drive motors _M1 and _M2 by providing a control circuit similar to the one described above in the control device.

(Effects) According to the present invention, by setting the ultrafiltration pressure value in advance, it is possible to achieve a water removal effect that is greater than the amount of water removed by venous pressure, as well as less than the amount of water removed by natural venous pressure. Or, not only can water removal be completely stopped, but even if the initial ultrafiltration pressure value at the start of dialysis deviates from the above set value, or if there are fluctuations in each pressure value during dialysis work, Since the ultrafiltration pressure value can always be feedback-controlled to the above-mentioned set value, the burden on nurses can be greatly reduced, and patient safety can also be greatly improved.

Furthermore, according to the embodiment of the present invention, since the ultrafiltration pressure value loaded on the dialyzer and the changes over time in each pressure value can be directly read from the display device, the optimal By setting the ultrafiltration pressure, the amount of water removed can be quickly controlled to suit the patient.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram showing one embodiment of the present invention, FIGS. 2a and 2b are a longitudinal cross-sectional view and an external view of the same main part, and FIG. 3 is a schematic diagram showing another main part of the invention. FIG. 4 is a graph showing a comparative example of the relationship between venous pressure and ultrafiltration rate in a dialyzer, and FIG. 5 is a longitudinal cross-sectional view of the pressure detection device. FIG. 6, which is an explanatory diagram of the display device, is a flowchart showing an embodiment of the main part of the present invention. 3... Dialyzer, 7... Dialysate circuit, 8... Dialysate side pressure device, 9... Blood circuit, 10... Blood circuit side pressure device, 15, 16... Air pump, 1
7, 18... Pressure gauge, 19... Natural venous pressure detection device, 27... Control device, 28... Ultrafiltration pressure value setting means, 29... Display device.

Claims (1)

[Claims] 1. A pressurizing device that sets the pressure downstream of a dialyzer in a blood circuit, and a blood circuit further downstream from the pressurizing device that detects the natural venous pressure value propagated to the blood circuit. a pressure device that sets the pressure downstream of the dialyzer in a dialysate circuit; an ultrafiltration pressure value setting means that presets an ultrafiltration pressure value; the detection device and the An automatic device that reads the respective pressure values of both pressurizing devices and automatically controls the detection device and both pressurizing devices so that the set ultrafiltration pressure value is set by the ultrafiltration pressure setting means. A hemodialysis control device comprising: a control means; 2 Pressure value on the downstream side of the dialyzer in the blood circuit,
to display the natural venous pressure value, the pressurization value on the downstream side of the dialyzer in the dialysate circuit, the ultrafiltration pressure value calculated by comparing these pressure values, and the set ultrafiltration pressure value, respectively. The hemodialysis control device according to claim 1, further comprising a display section.