JPH0422587B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a blood purification device, particularly to a blood purification device that effectively achieves blood purification while preventing the occurrence of a drop in blood pressure, an imbalance syndrome, etc. that are often observed in blood purification operations. The present invention relates to an improvement in a blood purification device that appropriately automatically controls the distribution of body fluid within a patient's body and the total amount of body fluid during blood purification.

Prior Art In recent years, in order to treat patients whose ability to remove waste products or excess water from body fluids is impaired due to renal failure, etc., blood taken outside the body is purified by dialysis or filtration through a semipermeable membrane. A blood purification device is used to return the blood to the body.

In order to perform safe and effective blood purification with this type of device, it is important to efficiently remove waste products or excess water accumulated in the body while maintaining an appropriate amount of circulating blood in the patient's body. be.

That is, rapid or excessive water removal can excessively reduce the amount of blood circulating in the patient's body, which can lead to complications such as hypotension, shock, or peripheral circulatory failure, whereas slow water removal can reduce blood volume. It is known that purification takes a long time, and if sufficient removal is not possible, it can cause high blood pressure, heart failure, etc.

For this reason, the inventors have already developed a device for automatically controlling the rate of water removal from a patient in order to maintain an appropriate amount of circulating blood in the body during blood purification.
Proposed as No. 37457. however,
Controlling the water removal rate alone is insufficient to reduce the amount of water accumulated in the patient's body, as well as urea, uric acid, creatinine,
In recent years, it has become clear that they are less effective in efficiently and safely removing solutes such as electrolytes.

In other words, the change (reduction) in the amount of circulating blood in the body due to blood purification is due to the change in body fluid distribution based on the adjustment effect of the effective osmotic pressure difference and the mechanical pressure difference in the body, that is, the change in body fluid distribution from within cells and between tissues to cell membranes. , the amount of water that passes through the capillary wall and moves into the blood vessel (as it may move in the opposite direction, the movement from the tissue side into the blood vessel is taken as a positive value), and blood purification outside the body. This is caused by the difference in the amount of water removed from the blood.

At this time, in order to rapidly remove the solutes accumulated in the body, if a dialysate or replacement fluid that does not contain any components of the solutes or has a low concentration is used, the osmotic pressure of the extracellular fluid decreases. Since the movement of water from inside the cells to the interstitial fluid side and further into the blood vessels is reduced, the water removal rate must be reduced in order to maintain an appropriate amount of circulating blood. On the other hand, when a solution with a high osmotic pressure is used as a dialysate or a replenisher in order to avoid the above-mentioned situation, there is a problem in that solutes that are highly concentrated to obtain the high osmotic pressure accumulate in the body.

Therefore, in order to remove water and various solutes in a well-balanced manner without excessively reducing the amount of blood circulating in the patient's body, it is necessary to maintain an appropriate water removal rate and reduce the amount of blood, interstitial fluid, and intracellular fluid in the patient's body. Appropriate distribution of body fluids such as fluids must be maintained;
For this purpose, it is necessary to maintain an appropriate osmotic pressure of the patient's blood (plasma) during blood purification, that is, the concentration of various solutes in the blood. The concentration of various solutes in the blood changes depending on the concentration of various solutes contained in the dialysate or replacement fluid used for blood purification. , it is necessary to appropriately control the solute concentration in replenishers, etc.

However, the appropriate concentration of solutes in the dialysate, replacement fluid, etc. differs depending on the osmotic pressure of the desired body fluid and the therapeutic or physiological conditions of each patient.
In conventional devices, it is not possible to determine this appropriate value, and as a result, it has been practically difficult to perform optimal blood purification for each patient.

Purpose of the Invention The present invention has been made in view of the above-mentioned conventional problems.The purpose of the present invention is to improve blood circulation in the patient's body in blood purification performed by drawing blood out of the patient's body and dialysis or filtration through a semipermeable membrane. To provide a blood purification device capable of stably and well-balanced waste removal while maintaining blood volume at an appropriate value.

Structure of the Invention In order to achieve the above object, the first
The invention relates to a blood purification device having a blood circulation system that circulates a patient's blood outside the body, and a blood purifier that purifies the blood by dialysis or filtration through a semipermeable membrane in the blood circulation system. a plasma osmotic pressure regulating means for regulating the osmotic pressure of plasma;
A blood circulation measuring device that measures changes in blood volume circulating in the body by measuring the concentration of solutes in blood that cannot pass through the semipermeable membrane of the blood purifier in the blood circulation system; A body circulating blood volume memory that stores a body circulating blood volume change program indicating a pattern of circulating blood volume change, and a body circulating blood volume determined from the body circulating blood volume change program and measurement by the body circulating blood volume measuring device. compared the amount of blood circulating in the body,
It is characterized by comprising a control means for controlling the plasma osmotic pressure adjusting means so that the two match according to the comparison result. The second invention as set forth in claim 8 is characterized in that a water removal amount adjusting means is further provided to adjust the amount of water removal and plasma osmotic pressure. A third aspect of the invention described in claim 9 is characterized in that a plasma osmolarity measuring device and a plasma osmolarity memory are further provided to simultaneously control both the blood volume circulating in the body and the plasma osmolarity. A fourth invention described in claim 13 is characterized in that a water removal amount measuring device and a water removal amount memory are further provided, and the amount of blood circulating in the body and the amount of water removed are controlled so that they respectively correspond to predetermined target values. do. The fifth invention described in claim 14 provides a device for measuring the amount of blood circulating in the body, the osmolarity of plasma, and the amount of water removed, as well as a memory for each, and measures the amount of blood circulating in the body, the plasma osmolarity, and the amount of water removed, respectively. It is characterized in that it is controlled to match a predetermined target value.

Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

First Embodiment FIG. 1 shows the basic configuration of a first embodiment in which the present invention is used for hemodialysis. Dialysate system 1 that supplies dialysate to the purifier
2, and a control system 14 for controlling the adjustment of the blood volume circulating in the body according to the change in blood volume circulating in the body detected in the blood circulation system 10, or in accordance with the hematocrit value in the embodiment.

The blood circulation system 10 takes the patient's blood from the inlet tube 16 to the dialyzer 18, cooperates with the dialysate system 12, and purifies the blood by dialysis and ultrafiltration.
The purified blood is returned into the patient's body through the return tube 20, and blood circulation at this time is performed by a circulation pump 22.

In the present invention, in addition to the above dialysis device, a hematocrit measuring device 24 is provided in the blood circulation system 10 in order to perform a safe and efficient waste removal action.
By this, the electrical resistivity of the blood is continuously measured to determine the hematocrit, and the circulating blood volume in the body, which is inversely proportional to this hematocrit, is determined in advance. It is characterized by adjusting the plasma osmotic pressure to match the change program and maintaining the blood volume circulating in the body at a desired value while performing an optimal purification effect. In the embodiment of FIG. 1, the plasma osmotic pressure is adjusted by controlling the electrolyte concentration of the dialysate, such as the concentration of sodium chloride.

The dialysate system 12 includes a known dialysate supply device 2.
6 is provided to supply dialysate to the dialyzer 18, and a vacuum pump 28 is connected to the discharge side of the dialyzer 18. Therefore, negative pressure is applied to the semipermeable membrane of the dialyzer 18 mainly due to the depressurizing action of the decompression pump 28, and water in the blood and solutes with a molecular weight of about 10,000 or less are transferred to the dialysate side through the semipermeable membrane. passed.

Also, from the dialysate supply device 26 to the dialyzer 18
A mixer 30 and a saline injector 32 forming a body circulating blood volume regulating system are on the supply path for supplying dialysate to the body.
is provided. The saline syringe 32 injects a controlled amount of concentrated sodium chloride solution into the mixer 30.
The mixer 30 mixes the supplied dialysate and concentrated sodium chloride solution and supplies the mixture to the dialyzer 18 . In this embodiment, the control system 14 controls the saline injector 3 according to the above-mentioned hematocrit value.
By changing the injection rate of 2 and appropriately controlling the sodium chloride concentration in the dialysate according to the condition of each individual patient, the patient's internal circulating blood volume can be maintained at the desired value and complications during blood purification can be prevented. This enables optimal purification without causing any illnesses.

The control system 14 includes a control device 34 for controlling the saline injector 32 based on the measured value of the hematocrit measuring device 24 and a predetermined program, and a control device 34 for controlling the saline injector 32 based on the measured value of the hematocrit measuring device 24 and a predetermined program, and a control device 34 for controlling the saline injector 32 based on the measured value of the hematocrit measuring device 24 and a predetermined program, and a control device 34 for controlling the saline injector 32 based on the measured value of the hematocrit measuring device 24 and a predetermined program. The setting device 36 includes a body circulating blood volume memory storing a body circulating blood volume change program during blood purification according to the patient's condition.

FIG. 2 shows the specific configuration of the hemacritt setting device 24 described above, which includes a resistance measuring section 37 that measures the electrical resistivity of blood introduced into the blood introduction tube 16, and a resistance measuring section 37 that performs temperature correction on the measured value. The temperature correction section 38 further includes a calculation section 40.

The resistance measuring section 37 has a measuring cell 42 connected in communication with the introduction pipe 16, and electrical resistivity is measured by a four-electrode method. In this example, in order to eliminate the influence of anisotropy in resistivity due to the flow of blood, the resistivity is measured in a direction in which the resistivity is equivalent to that when the blood is at rest. That is, the insulation tube 4
4, a pair of current electrodes 46, 48 and a pair of voltage electrodes 50, 52 are arranged. The voltage electrodes 50 and 52 are installed in parallel inside the current electrodes 46 and 48, respectively, and as a result, the resistivity of the blood in the diagonal direction with respect to the blood flow direction is reduced. is measured. Current electrodes 46, 4
8 is supplied with a measuring current from an AC constant current source 54, and the electrical resistivity of the blood at this time is measured by voltage electrodes 50,
Voltage electrode 5 to detect as voltage value between 52
A voltmeter 56 is connected to the terminals 0 and 52, and its output is supplied to the temperature correction section 38.

Further, in order to perform correction based on the temperature of the blood, the insulating tube 44 is provided with a thermistor 58 for temperature measurement, the output end of which is connected to the temperature correction section 38.

Note that in this embodiment, the AC constant current source 54
supplies a current of 25 KHz and 30 μAr.ms to maintain safety for the human body and avoid the influence of polarization, and a voltmeter 56 converts the AC voltage into a DC voltage and supplies it to the temperature correction unit 38.

The electrical resistivity obtained from the resistance measuring section 36 as described above is subjected to desired temperature correction by the temperature correcting section 38 based on the resistance value of the thermistor 58. Considering that, in general, when the temperature rises by 1°C, the electrical resistivity decreases by about 2% near body temperature.
Temperature correction is performed to convert to electrical resistivity at 37°C.

Furthermore, this temperature-corrected resistivity is calculated by the calculation unit 40.
The hematocrit is calculated by In other words, the electrical resistivity of blood around 25KHz = b
[Ω・cm] and hematocrit Ht by centrifugation method
[%] is 〓b=K ₂ e ^{1/K1 Ht} ...(1) However, K ₁ ≒ 47, K ₂ ≒ 54, and from this,
The hematocrit Ht is determined by Ht=K ₁ ln〓b/K ₂ (2), and the arithmetic unit 40 includes an attenuator 60 and a logarithmic amplifier 62 for obtaining the equation (2).

The present invention is characterized in that the control system 14 controls the amount of blood circulating in the body using the hematocrit determined from the electrical resistivity of the blood as described above, and FIG. 3 shows a preferred embodiment of the control system. It is shown.

In an embodiment, a setting device 36 for storing changes in hematocrit is a keyboard 64 for inputting a program, and a circulating blood volume memory for storing this in an embodiment of a preferable internal circulating blood flow rate change during dialysis determined from past records of the patient. It also includes a hematocrit memory 66.

The control device 34 controls the hematocrit memory 66.
saline injector 32 of the dialysate system 12 based on the program and the measurement value of the hematocrit meter 24.
For this purpose, a subtractor 68 is provided to calculate the difference between the program in the hematocrit memory 66 and the hematocrit Ht during dialysis detected from the hematocrit measuring device 24, and to integrate the difference. an integrator 70 and a differentiator 72 that differentiates the difference
and an adder 74 that weights and adds the outputs of the subtracter 68, integrator 70, and differentiator 72 to obtain a control signal.

In the present invention, hematocrit
When Ht is smaller than the programmed value, the injection rate of the syringe 32 is gradually decreased, and conversely, when the hematocrit Ht is greater than the programmed value, the injection rate of the syringe 32 is gradually increased to increase plasma osmolality. The amount of blood circulating in the body is maintained based on the adjustment of blood flow.

The first embodiment of the present invention has the above configuration, and its operation will be explained below.

Before starting hemodialysis, the patient's past dialysis records, weight gain from the end of the previous dialysis to the start of the current dialysis,
Based on blood pressure and other patient records, the setting device 3 will program the optimal hematocrit for the patient.
4, after which the well-known hemodialysis is started.

In the present invention, hematocrit measurement is performed continuously during hemodialysis, and thereby the control system 1
2 controls the purification action according to the set program.

Generally, in hemodialysis, mechanical pressure from the blood circulation circuit side, mechanical pressure from the vacuum pump 28, and osmotic pressure of the blood and dialysate are applied to the semipermeable membrane of the dialyzer 18, and the desired level is thereby applied. An extreme pass is being carried out. That is, by keeping the pressure on the dialysate side lower than the pressure on the blood side, water in the blood is ultrafiltered to the dialysate side through the semipermeable membrane. At this time, the amount of water that is passed through per unit time is not equal to the amount of water that moves from body tissues into blood vessels, and as a result, fluctuations occur in the amount of blood circulating in the patient's body during hemodialysis. . Usually, one to three times of hemodialysis (about 4 to 6 hours) removes about 1 to 3 volumes of water, and the amount of blood circulating in the body decreases with this water removal. The present invention is characterized in that the blood volume circulating in the body is controlled to be constantly maintained at a predetermined programmed value during hemodialysis. Noting that the blood volume circulating in the body is inversely proportional to hematocrit, the saline injector 32 is controlled by measuring the hematocrit and comparing it with a predetermined program.

Therefore, in the first embodiment, when the movement of water from between intracellular tissues into blood vessels decreases and the volume of circulating blood in the body decreases rapidly due to water removal, the hematocrit at this time becomes larger than the set value. Therefore, the injection amount of the saline injector 32 is increased to increase the plasma osmotic pressure and promote the movement of water from the tissue side into the blood vessels to prevent a decrease in the amount of circulating blood in the body, and vice versa. Similarly, the amount of circulating blood is appropriately controlled. Therefore, by performing control according to such a predetermined program, it becomes possible to appropriately remove waste products in accordance with the patient's condition.

Second Embodiment FIG. 4 shows a second embodiment in which the present invention is applied to a blood sampling device.
An embodiment is shown, and the same members as those in the first embodiment are given the same reference numerals and their explanations will be omitted.

In the second embodiment, as in the first embodiment, the amount of blood circulating in the body during blood purification is compared with the patient's program, and the plasma osmotic pressure during purification is also compared with a predetermined set value to optimize the purification effect. It is characterized by carrying out the following.

In the blood filtration device of this embodiment, unlike the first embodiment, blood filtration
The purification effect is carried out by the hemofilter 74 provided in the blood circulation system 10 and the decompression pump 84 of the drainage system 82 which is connected to the excess liquid side of the hemofilter 74 to remove plasma components containing waste products. A portion of the blood is ultrafiltered and at the same time the blood circulation system 10 is supplied with a replenisher from the replenisher system 76 and the purified blood is returned to the patient's body.

In this embodiment, the replacement fluid system 76 has a sodium concentration that is normally used in hemodialysis or a slightly lower concentration (e.g.
135mEq/~140mEq/) replenishment fluid source 77;
A first supply pump 79 that supplies this replenisher to the blood circulation system 10 and a concentrated sodium chloride (hereinafter referred to as
A second supply pump 80 for supplying this replenishment fluid (concentrated NaCl solution) to the blood circulation system 10 , the first supply of this replenishment fluid system 76 The pump 79 forms a water removal amount adjustment section, the second supply pump 80 forms a plasma osmotic pressure adjustment section, and the body circulating blood volume adjustment system is formed from the water removal amount adjustment section and the plasma osmotic pressure adjustment section. There is. By changing the rotational speed of both supply pumps 79 and 80 in accordance with a control signal from the control system 14, the amount of replenisher supplied into the blood circulation system 10 and the NaCl concentration are adjusted, and the blood circulating in the body is adjusted. The amount and concentration of NaCl in the circulating blood can be controlled to a predetermined amount.

In this embodiment as well, the replenisher system 76 is controlled by measuring the hematocrit in the blood of the blood circulation system 10 and thereby adjusting the amount of circulating blood in the body. When the electrolyte concentration and electrical resistivity of plasma change, such as by injecting a large amount of replenishing fluid with an electrolyte concentration different from that of body fluids into the body, the electrical resistivity of blood alone (2)
If the hematocrit Ht is determined by the formula, an error will occur. Therefore, in this example, the electrical resistivity ρ _b (Ωcm) of the blood as well as the electrical resistivity ρ _s (Ωcm) of the excess fluid, which is a part of the plasma, were determined, and the following formula (3) was calculated from both electrical resistivities: Hematocrit is calculated using the formula and formula (4).
Find Ht (%).

ρ _b =K ₂・ρ _s ……(3) e ^{1/K1 Ht} = ρ _b /54+(54−ρ _p )(e ^{1/K1 Ht} ) ² /5
4...(4) However, equation (3) is a formula for calculating the electrical resistivity ρ _p of plasma from the electrical resistivity ρ _s of the excess fluid, and K ₂ varies slightly depending on the protein concentration in the plasma. K ₂ =
1.05 and K ₁ =47 is suitable.

FIG. 5 shows the configuration of the hematocrit measuring device 24 of the second embodiment, in which the drained fluid from the hemofilter 74 in the blood circulation system 10 is supplied to the hematocrit measuring device 24.

As is clear from FIG. 5, the hemofilter 74
Resistance measuring sections 37a and 37b are provided on the blood inlet side and the excess liquid outlet side, respectively, and both of these measuring sections have the same structure as that shown in FIG. The electrical resistivity obtained from both the resistance measuring sections 37 is calculated by the temperature correcting section 38.
37℃ by temperature correctors 86a and 86b, respectively.
After temperature correction is performed based on , the electrical resistivity ρ _b of the blood and the electrical resistivity ρ _s of the superfluid are supplied to the calculation unit 40 to perform a desired hematocrit calculation.

The calculation unit 40 calculates ρ _b using the relationship of equations (3) and (4).
and ρ _s to calculate and output the hematocrit Ht. That is, first, an amplifier 87 with an amplification factor of _K2 calculates ρ _p from ρ _s , and then an arithmetic circuit 88 calculates a hematocrit Ht based on equation (4).

Furthermore, in this example, as mentioned above, the NaCl concentration in the replenisher is changed to control the NaCl concentration in the plasma (that is, plasma osmotic pressure), and the water accumulated in the cells is transferred to the outside of the cells. Maintains proper body fluid distribution by regulating movement, but NaCl in plasma
In order to prevent excessive or unnecessary increases in concentration, the NaCl concentration in plasma is monitored and the NaCl concentration in the replenisher is controlled based on this. Most of the NaCl in plasma is divided into Na ions and Cl ions, and these account for most of the electrolytes in plasma, so the NaCl concentration in plasma can be determined from the plasma electrical resistivity ρ _p . In this embodiment, the fluid resistance measuring section 37, temperature corrector 86b and amplifier 87 in the hematocrit measuring device 24 form a plasma osmotic pressure measuring section.

As described above, when the hematocrit Ht is determined by taking into account changes in plasma electrical resistance due to blood flow and its effects, _the control system
4 controls the replenishment fluid system 76 forming the internal circulating blood volume adjustment system in this embodiment.

FIG. 6 shows the control system of the second embodiment. The setting device 36 includes a hematocrit memory 66.
Separately from this, there is a plasma osmotic pressure memory that stores the upper limit of the NaCl concentration in plasma as the plasma electrical resistivity ρ _p (as the NaCl concentration increases, ρ decreases, giving the lower limit of _{ρ p )} . In the embodiment, a plasma resistance memory 90 is provided, in which the hematocrit program and the set plasma resistance value are individually supplied to the control device 34.

As in the first embodiment, the control device 34 includes a subtracter 68 that generates a control signal for the supply pumps 79 and 80 of the replenisher system 76 from the program in the memory 66 and the hematocrit Ht continuously measured during blood purification.
a, integrator 70, differentiator 72, adder 74a, and adder 74b, plus plasma resistance memory 90
When the subtracter 68b calculates the difference between the set value of and the measured plasma electrical resistivity _ρp , and the error approaches 0 or negative, the output signal of the adder 74b is limited or decreased and output to the supply pump 80. A limiter 92 is provided. In the second embodiment, the circulating blood volume adjusting system includes a water removal amount adjusting section comprising a pump 79 that supplies a replenisher having an osmotic pressure equivalent to or slightly lower than that normally used, to the blood circulation system 10, as described above. , and a plasma osmolarity adjustment unit consisting of a supply pump 80 that supplies a high osmotic pressure replenisher. A subtractor 74b is provided independently, and they perform an addition operation by appropriately weighting the deviation signal outputted from the subtractor 68a, its differential signal, and its integral signal.

The second embodiment of the present invention has the above configuration, and its operation will be explained below.

In the second embodiment, before the start of blood purification, a program for changing the blood volume in the body during blood purification and a set value for plasma osmolality are recorded in the hematocrit memory 66 and the plasma resistance memory 90, respectively, At the same time as the blood flow starts, the hematocrit Ht and plasma electrical resistivity _ρp , which correspond to the circulating blood volume and plasma osmolality, which are measured from the patient's blood and ultrafiltration fluid, are compared with the program and set values, respectively, and the supply of replacement fluid is performed. is appropriately controlled, and the amount of blood circulating in the body during purification is maintained at a predetermined value.

That is, if sufficient water is not removed from the patient, the hematocrit Ht will be smaller than the predetermined program, so that the output of the adder 74a decreases the injection speed of the infusion pump 79 and increases the amount of water removed. At the same time, the output of the adder 74b reduces the infusion rate of the infusion pump 80 to lower the NaCl concentration in the replenisher, effectively removing excess water accumulated in the patient's body, and lowering the patient's plasma osmolarity. Prevent rising. On the other hand, if the circulating blood volume in the body is smaller than the programmed value, the injection speeds of both the injection pumps 79 and 80 are increased to reduce the amount of water removed and to reduce the amount of water in the replenisher.
Increasing the NaCl concentration can promote the movement of water from the intracellular to the extracellular space to compensate for the circulating blood volume in the body.

Furthermore, in this embodiment, when the above control is performed, the injection volume of the injector 80 increases, the patient's plasma osmotic pressure rises, and when the plasma electrical resistivity ρ _p becomes smaller than the set value, the above-mentioned It is possible to limit the injection rate of the injector 80 to prevent excessive increases in plasma osmolality.

As described above, according to the second embodiment, by preventing an excessive decrease in the blood volume circulating in the patient's body and an excessive increase in plasma osmolarity, it is possible to achieve a well-balanced waste treatment without causing complications. It can perform a substance removal action.

Third Embodiment FIG. 7 shows a third embodiment of the present invention, in which the same members as those in the second embodiment are designated by the same reference numerals and their explanations will be omitted.

Similar to the second embodiment, the third embodiment is characterized in that control is performed using hematocrit and plasma osmotic pressure, and the amount of water removed is continuously measured, so that appropriate blood purification control is performed by these three factors.

In the third embodiment, a drain tank 94 is provided to store the ultrafiltrate discharged from the drain system 82 in order to measure the amount of water removed. Together with the supply devices 77 and 78, they are held constant on a holding table 96. The total weight or weight change on the holding table 96 is then measured by a weighing device 98. Therefore, the difference between the amount of fluid drained from the patient's blood and the amount of replenisher refilled into the blood is measured, and this is sent from the weighing device 98 to the control device 34 of the control system 14 as a water removal amount signal. Supplied.

FIG. 8 shows the configuration of the control system 14 in the third embodiment. Separate from the hematocrit memory 66 and plasma resistance memory 90, the setting device 34 is provided with a water removal amount memory 100 that stores a preferred water removal amount program during purification based on patient records. The program, plasma resistance and water removal rate programs are separately supplied to the controller 34.

In addition to the components of the second embodiment, the control device 34 of the third embodiment further includes the weighing device 9 during cleaning.
Water removal amount memory 1 from the water removal amount continuously measured in step 8.
A subtracter 68c that subtracts the output of 00 and the subtracter 6
An integrator 102 integrates the output of the integrator 8c, and the output of the integrator 102 and the output of the adder 74a are weighted and added according to the patient, and a control signal is output to the supply pump 79 of the water removal amount adjustment section. Adder 10
4 is provided.

The control system 14 of the third embodiment has the above configuration, and when the hematocrit and water removal amount measured during purification are large, the injection speed of the injection pump 79 is increased, and conversely, each measured value is lower than the set value. If it is small, reduce the injection rate. In addition, if the measured water removal amount is smaller than the set value but the hematocrit measurement value is larger than the set value, or vice versa, replenisher fluid is injected based on the difference between each measured value and the predetermined set value. Control of increasing or decreasing the speed is performed arbitrarily, and how much importance is given to both the hematocrit and the amount of water removed at this time is determined by the outputs of the adder 74a and the integrator 102 in the addition operation of the adder 104. Determined by weighting appropriate for the patient.

Furthermore, control of the plasma osmotic pressure adjusting section based on the electrical resistance of hematocrit and plasma is performed in the same manner as in the second embodiment.

Therefore, according to the third embodiment, the amount of blood circulating in the body is maintained properly during blood purification and the necessary water removal is performed, and the above two requirements are met because a large amount of waste products are accumulated in the patient's body. If the two cannot be compatible, it is possible to remove waste while maintaining an appropriate balance between the two, according to preset weighting.

Other Modifications of the Invention In each of the embodiments described above, blood resistivity is measured using a measurement cell connected to an extracorporeal blood circulation tube, but the invention is not limited to this.
For example, measurements can be made by arranging the electrodes, which are not affected by blood flow, at the bottom of a known air chamber that is usually provided on the extracorporeal blood circulation circuit to remove air bubbles, the explanation of which is omitted in this specification. You can also do that.

Further, in each of the embodiments described above, the hematocrit is directly input to the control system, but in the present invention, it is also possible to input the reciprocal of the hematocrit and other calculation results to the control system.

Further, in each of the above embodiments, hematocrit measurement is performed as a stable means of measuring the circulating blood volume in order to obtain a highly reliable measurement of the circulating blood volume in the body, but in the present invention, in addition to this, It is also possible to determine the protein concentration in blood by measuring osmotic pressure using a semipermeable membrane, and calculate the change in circulating blood volume from this change in protein concentration.

In addition, when measuring circulating blood volume using this osmotic pressure, a minute pressure difference (30 to 35 mmHg) is generated through a semipermeable membrane.
must be measured, and the characteristics of the semipermeable membrane must be strictly controlled.

Further, in each of the above embodiments, the adjusting section adjusts the injection amount of the concentrated NaCl solution in order to control the NaCl concentration of the replenisher, but the present invention is not limited to this. Upper and lower sodium concentrations (e.g. 180 mEeq/ and 135
The ratio of the injected amounts of two types of replenishers having mEeq/) may be controlled, and furthermore, substances other than sodium, such as mannitol, glycerol, albumin, etc., may be used as a substance that changes plasma osmotic pressure. However, when these substances are used to control plasma osmolality, a means that can accurately measure changes in their concentration should be used to measure plasma osmolarity, and these substances should be used to measure circulating blood volume. It is necessary to use means that are not affected. For example, when albumin is used to control plasma osmotic pressure, it is necessary to use a hematocrit meter or the like as a means for measuring circulating blood volume.

Furthermore, in the first embodiment, the water removal amount adjusting section of the body circulating blood volume adjusting system changes the ultra-limit overspeed of the blood purifier (dialyzer) by adjusting the amount of water removed on the dialysate side of the blood purifier (dialyzer). Although the pressure (negative pressure) is adjusted, the present invention is not limited to this. For example, the pressure (positive pressure) applied to the blood side of the blood purifier can also be adjusted.

Effects of the Invention As explained above, according to the present invention, the volume of blood circulating in the body of a patient undergoing blood purification is determined from the concentration of solutes that do not pass through a semipermeable membrane, and the blood volume circulating in the body is determined by adjusting the plasma osmotic pressure. Control quantity. For this reason,
Blood purification can be performed according to the patient's blood condition, and a well-balanced waste removal action can be performed while maintaining the amount of blood circulating in the body at an appropriate value.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram showing a preferred first embodiment of the blood purification apparatus according to the present invention, FIG. 2 is an explanatory diagram showing a hematocrit measuring device of the first embodiment, and FIG.
The figure is a block circuit diagram of the control system in the first embodiment, FIG. 4 is a block circuit diagram of the second embodiment of the present invention, FIG. 5 is an explanatory diagram showing the hematocrit measuring device of the second embodiment, and FIG. 7 is a block circuit diagram showing the control system of the second embodiment, FIG. 7 is a block circuit diagram of the third embodiment of the present invention, and FIG. 8 is a block circuit diagram showing the control system of the third embodiment. 10... Blood circulation system, 12... Dialysate system, 14
... Control system, 18 ... Dialyzer, 24 ... Hematocrit measuring device, 28 ... Decompression pump, 30 ... Air mixture, 32 ... Saline injector, 34 ... Control device, 36 ... Setting device, 37...Resistance measuring section, 42
...Measurement cell, 44...Insulation tube, 46, 48...
Current electrode, 50, 52... Voltage electrode, 54... AC constant current source, 56... Voltmeter, 66... Hematocrit memory, 74... Hemofilter, 76...
Replenisher system, 79, 80... Supply pump, 90...
Plasma resistance memory, 98... Weighing device, 100...
Water removal amount memory.

Claims (1)

[Scope of Claims] 1. A blood purification device having a blood circulation system that circulates a patient's blood outside the body, and a blood purifier that purifies the blood by dialysis or filtration through a semipermeable membrane in the blood circulation system. , a plasma osmotic pressure regulating means for regulating the osmotic pressure of plasma in the blood circulation system; A body circulating blood volume measuring device for measuring changes in volume; a body circulating blood volume memory storing a body circulating blood volume change program indicating a pattern of body circulating blood volume change during blood purification; and a body circulating blood volume change program. The amount of circulating blood in the body determined from the amount of blood circulating in the body is compared with the amount of blood circulating in the body measured by the body circulating blood amount measuring device, and the plasma osmolarity adjusting means is controlled according to the comparison result so that the two match. A blood purification device comprising: a control means; 2. The plasma purification device according to claim 1, wherein the plasma osmotic pressure adjusting means changes the electrolyte concentration in the dialysate or the replenisher. 3. The blood purification device according to claim 1, wherein the circulating blood volume measuring device is a hematocrit measuring device that detects changes in the amount of blood circulating in the body based on changes in hematocrit. 4. In the device according to claim 3, the hematocrit measuring device includes a resistance measuring section for measuring blood electrical resistivity in the blood circulation system, a temperature correcting section for temperature compensating the measured electrical resistivity, and a temperature correcting section for temperature compensating the measured electrical resistivity. A blood purification device comprising: a calculation unit that calculates hematocrit from a hematocrit rate. 5. In the device according to claim 4, the resistance measuring section for measuring blood electrical resistivity is arranged in an insulating tube connected to the blood circulation system on a symmetrical side with respect to the central axis thereof and a predetermined distance apart in the central axis direction. A blood purification device comprising a measurement cell having at least one pair of electrodes provided at different positions. 6. In the device according to any one of claims 4 and 5, the resistance measurement section is provided with a measurement cell for measuring the electrical resistivity of plasma components in blood, and the electrical resistivity of blood and the plasma components are measured. A blood purification device characterized by calculating hematocrit from both electrical resistivity. 7. The device according to claim 6, further comprising a filter for ultrafiltrating a part of plasma in the blood circulation system, and a measurement cell for measuring the electrical resistivity of plasma components in a filtration waste liquid path of the filter. A blood purification device characterized by: 8. In a blood purification device having a blood circulation system that circulates the patient's blood outside the body, and a blood purifier that purifies the blood by dialysis or filtration through a semipermeable membrane in the blood circulation system, from the blood circulation system. a water removal amount adjustment means for adjusting the amount of water removed; a plasma osmotic pressure adjustment means for adjusting the osmotic pressure of plasma in the blood circulation system; A body circulating blood volume measuring device that measures changes in body circulating blood volume by measuring solute concentration in blood, and a body circulating blood volume measuring device that stores a body circulating blood volume change program that indicates a pattern of body circulating blood volume change during blood purification. Comparing the circulating blood volume in the body determined from the circulating blood volume memory and the body circulating blood volume change program with the body circulating blood volume measured by the body circulating blood volume measuring device, A blood purification apparatus comprising: a control means for controlling the water removal amount adjusting means and the plasma osmotic pressure adjusting means so that they match. 9. In a blood purification device having a blood circulation system that circulates the patient's blood outside the body, and a blood purifier that purifies the blood by dialysis or filtration through a semipermeable membrane in the blood circulation system, from the blood circulation system. a water removal amount adjustment means for adjusting the amount of water removed; a plasma osmotic pressure adjustment means for adjusting the osmotic pressure of plasma in the blood circulation system; A circulating blood volume measuring device that measures changes in circulating blood volume in the body by measuring solute concentration in the blood; A plasma osmolarity measuring device that measures the osmotic pressure of plasma in the blood circulation system; A body circulating blood volume memory storing a body circulating blood volume change program indicating a pattern of circulating blood volume change; a memory storing a plasma osmolarity set value; and a body circulating blood volume memory storing a body circulating blood volume change program and a plasma osmolarity set value. Compare the required body circulating blood volume and plasma osmolarity with the body circulating blood volume measured by the body circulating blood volume measuring device and the plasma osmolarity measured by the plasma osmolarity measuring device, and A blood purification device comprising: control means for controlling the water removal amount adjusting means and the plasma osmotic pressure adjusting means so that they match each other according to a comparison result. 10. The device according to claim 9,
A blood purification device characterized in that the plasma osmolarity measuring device measures the electrolyte concentration of plasma, and the plasma osmolarity adjusting means changes the electrolyte concentration in the dialysate or the replacement fluid. 11. The device according to claim 10,
A plasma osmolarity meter is a blood purification device that measures electrolyte concentration from the electrical resistivity of plasma. 12. The device according to claim 11,
A plasma osmolarity meter is a blood purification device that measures electrolyte concentration from the electrical resistivity of plasma. 13. In a blood purification device having a blood circulation system that circulates the patient's blood outside the body, and a blood purifier that purifies the blood by dialysis or filtration through a semipermeable membrane in the blood circulation system, from the blood circulation system. a water removal amount adjustment means for adjusting the amount of water removed; a plasma osmolarity adjustment means for adjusting the osmotic pressure of plasma in the blood circulation system; A body circulating blood volume measuring device that measures changes in body circulating blood volume by measuring solute concentration in blood, a water removal amount measuring device that measures water removal amount by the water removal amount adjusting means, and body circulation during blood purification. A body circulating blood volume memory that stores a body circulating blood volume change program indicating a pattern of blood volume change, a water removal amount memory storing a water removal amount program, and a body circulating blood amount memory that stores a body circulating blood volume change program and a water removal amount program. The plasma osmotic pressure regulating means and A blood purification device comprising: control means for controlling the amount of water removed by the water removal amount adjusting means. 14. In a blood purification device having a blood circulation system that circulates the patient's blood outside the body, and a blood purifier that purifies the blood by dialysis or filtration through a semipermeable membrane in the blood circulation system, from the blood circulation system. a water removal amount adjustment means for adjusting the amount of water removed; a plasma osmotic pressure adjustment means for adjusting the osmotic pressure of plasma in the blood circulation system; A circulating blood volume measuring device that measures changes in blood volume circulating in the body by measuring solute concentration in the blood; a plasma osmolarity measuring device that measures the osmotic pressure of plasma in the blood circulation system; and the water removal amount adjusting means. A water removal amount measuring device that measures the amount of water removed by blood purification, an internal circulating blood volume memory that stores an internal circulating blood volume change program that shows the pattern of changes in internal circulating blood volume during blood purification, and a plasma osmolarity that stores the set value of plasma osmolarity. an osmotic pressure memory and a water removal amount memory that stores a water removal amount program indicating a pattern of changes in the amount of water removed; The amount of water removed determined from the water removal program, the amount of blood circulating in the body measured by the blood volume measuring device, the plasma osmolarity measured by the plasma osmolarity measuring device, and the amount of water removed by the amount measuring device. A control means for comparing the amounts of water removed and controlling the amount of water removed by the removal amount adjusting means and the plasma osmotic pressure adjusting means so that the amounts of water removed correspond to each other according to the results of these three comparisons. blood purification device. 15 In the device according to claim 14, the plasma osmolarity measuring device measures the electrolyte concentration of the plasma, and the plasma osmolarity adjustment section of the body circulating blood volume adjustment system measures the electrolyte concentration in the dialysate or replacement fluid. A blood purification device characterized by changing concentration.