JPH01131669A - Blood dialyzer - Google Patents

Abstract

PURPOSE:To accurately, automatically measure and control an amount of removed water so as to safely dialyze blood, by converting a momentary amount of removed water periodically measured into an amount of water to be removed for a certain time period (time period for completing dialysis) and calculating the difference between the converted value and an amount of water-removal previously set. CONSTITUTION:Pulse counts indicating an inflow amount and an outflow amount of a solution to be dialyzed are periodically detected with oval meters 3 and 6, and are sent as pulse signals to a means 11 for calculating momentary amount of removed water. A converting means 31 for amount of water-removal calculates a speed ot a momentary water-removal from an increment of pulse counts, which indicate momentary amounts of removed water and which are periodically calcuated by the means 11, and then, using the speed calculated, converts the momentary amounts of removed water into an amount of water to be removed for a time period for completing dialysis. A signal from the means 31 is sent to a means 32 for calculating difference between converted value and set value, where the signal is compared with an amount of water-removal previously set by a means 10 for setting amount of water-removal and thereby the difference between both the values is calculated. The difference is converted into a membrane pressure difference to be accorded with a value set by a means 13 for setting constant membrane pressure difference. The amount of water-removal is accurately controlled in the above manner.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a hemodialysis apparatus equipped with water removal amount control means that automatically adjusts the water removal rate and amount of water removed during hemodialysis. .

(Prior Art and Problems) In hemodialysis, the amount of water removed must be extremely accurately adjusted in order to reduce the patient's weight. This is because rapid water removal will not cause shock to the patient, and the total amount of water removed is set at an amount that fully takes into account the health condition of the patient.

In general hemodialysis, the total amount of water removed by UF (ultrafiltration) is 2 to 31 in one dialysis, whereas the amount of dialysate is 1,501. Therefore, the amount of water removed corresponds to only 24 to 4 of the dialysate, and in order to control the amount of water removed within a practical range (±5 Q cc ), the amount of dialysate must be adjusted to 0.03 It must be within an error range of 0.04% to 0.04%.

However, in conventional hemodialysis, the patient's weight is measured before dialysis, and what is the weight? After setting the dialysis fluid flow rate, the dialysate flow rate and dialysis time were set based on the data from the previous dialysis, and the dialysate flow rate remained constant. Therefore, the above method is an extremely primitive method in which the final amount of water removed can only be determined by measuring the patient's weight after dialysis and calculating the difference between the patient's weight and the weight before dialysis. It is difficult to accurately adjust the amount of water.

Furthermore, there is an apparatus which is one step more advanced than the above-mentioned adjustment method, for example, as disclosed in Japanese Patent Application Laid-Open No. 54-27296.

This device measures the amount of dialysate discharged sequentially using a cylinder.
The configuration is such that the flow rate of the dialysate is adjusted based on changes in the discharge amount.

However, even with the above-mentioned adjustment device, the measurement of the amount of water removed is not very accurate, and there is a risk that fluctuations between the water removal stations will be large, and the final amount of water removed cannot be expected to be accurate. Furthermore, no countermeasures have been taken against unforeseen accidents such as clogging of the flow path.

Furthermore, in conventional hemodialysis, it is necessary for a large number of skilled staff to attend to each patient, and many problems remain in terms of costs and securing personnel.

Furthermore, it is not enough to keep the water removal rate constant over time, but since there is a time-varying characteristic of the water removal rate that suits each patient, it is possible to perform dialysis while faithfully following these characteristics. It is desired to develop an adjustment device that can perform this.

Therefore, an object of the present invention is to provide a hemodialysis post-dialysis device equipped with water removal amount control means that can accurately and automatically measure and control the amount of water removed and safely perform hemodialysis.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides dialysate that is introduced into a hemodialyzer from a dialysate supplier 1 through a dialysate inflow path 2, as shown in FIG. a first flowmeter 3 that measures the flow rate of the dialysate, and a second flowmeter 6 that measures the flow rate of the dialysate containing waste products in the blood, which is led out from the hemodialyzer 2 via the dialysate outflow path 4. , two pressure sensors 7.8 provided in the dialysate outflow path 4 and the blood circulation path 9 to detect the transmembrane pressure difference of the hemodialyzer, and a total amount of water removed from the patient M. The instantaneous water removal amount calculating means 11 calculates the instantaneous water removal amount from comparison with the total water removal amount calculated last time, and the total water removal amount set by the water removal amount setting means 10 converts the instantaneous water removal amount into the total water removal amount. A water removal amount calculating means 12 calculates the difference in the total amount of water removed from a comparison with the amount of water removed; A transmembrane pressure difference setting means 13 that changes the set value of the transmembrane pressure difference by adding it to the set value of the transmembrane pressure difference, and a transmembrane pressure difference set by the transmembrane pressure difference setting means 13 and the pressure and a transmembrane pressure difference control means 15 that controls the rotation speed of the pump while comparing the transmembrane pressure difference detected at the pump f7°8 until the deviation value between the two becomes zero, and the above-mentioned amount of water removed is The water removal rate is controlled so that dialysis is performed in accordance with the setting value of the setting means 10.

(Function) In this invention, the instantaneous amount of water removed measured at regular intervals is first converted into the amount of water removed after a certain period of time (scheduled end time of dialysis).
Calculate the difference between this converted value and the preset water removal amount,
Next, this difference in the amount of water removed is converted into a transmembrane pressure difference and added to the previously calculated transmembrane pressure difference set value, and this added value is set as the next transmembrane pressure difference set value. It is possible to obtain an accurate amount of water removal that is adapted to the patient's changing condition during hemodialysis, and it is also possible to quickly respond to unexpected accidents.

(Example) FIG. 2 is a configuration diagram showing a hemodialysis apparatus according to an example of the present invention. In FIG. 2, a sublayer 20 mixes water and a dialysis stock solution to produce a suitable dialysate. This dialysate is pressurized by the pressurizing pump 21 and flows in the direction of arrow F1, and is heated to the optimum temperature for dialysis by the heater 22.
It is degassed by the degassing pump 23, and the flow is further controlled by the regulating valve 24.
After the flow rate is adjusted to a constant level, the oval meter (first
(flow meter) 3 into the hemodialyzer. - The dialysate that has absorbed waste products inside the hemodialyzer flows out of the hemodialyzer ○, passes through an oval meter (second flow meter) 6, and is discharged by a pump 16.

On the other hand, the blood taken out from the human body M is applied a flow velocity in the direction of arrow F2 by the blood pump 25, and is sent to the hemodialyzer. The blood dialyzed by the hemodialyzer is returned to the human body M through the air detector 26. 27 is a heparin pump that mixes a small amount of urine components into the blood to prevent blood coagulation during hemodialysis. Reference numeral 28 is a bureau switch that immediately cuts off the flow of blood when the injection needle used to collect blood becomes clogged.

7.8 is a pressure sensor provided in the dialysate outflow path and the blood flow path, and the transmembrane pressure difference can be calculated by these two pressure sensors.

The oval meters 3 and 6 periodically detect the number of pulses indicating the inflow and outflow of the dialysate, and the data is sent as a pulse signal to the instantaneous water removal amount calculation means 11. As shown in FIG. 4, this instantaneous water removal amount calculation means 11 calculates the number of pulses [C1n(tn)] representing the inflow of dialysate detected by the oval meter 3 and the outflow of dialysate detected by the oval meter 6. The number of pulses representing the amount [Co
ut(tn) ) to the difference [:CD(tn)=Con
t(tn)-C1n(tn):l is calculated and sent to the water removal amount control means 12. The water removal amount control means 12 generates a pulse representing the instantaneous water removal amount! , : [CD(tn)']
The system comprises a means 31 for converting the amount of water removed to a water removal amount [UFR(tn)] at the end of dialysis, and a means 32 for calculating the difference between the converted amount of water removal and a preset amount of water removal [UFR(tn)]. There is. In the water removal amount conversion means 31, the increase in the number of pulses representing the instantaneous water removal amount calculated periodically by the instantaneous water removal amount calculation means 11 is 1:cD(tn)-Co(tn-+))
The instantaneous water removal rate is first calculated, and then the amount of water removed after dialysis is determined from the obtained water removal rate. For example, as shown in FIG. 3, magnets 32 are embedded in symmetrical positions of one rotor 31 of an oval meter, and the magnets are attached to the surface of a housing 330 of the oval meter to create a magnetically sensitive sensor (not shown). In the case of detection, two pulses are transmitted when the rotor 31 rotates once. Assuming that this rotor 31 discharges 1!1 d of liquid per revolution, the oval meter rate will be 0.5 d/pulse. Therefore, for example, if the instantaneous water removal amount is calculated every minute, the instantaneous water removal amount will increase,
In other words, if there is an increase of 30 pulses per minute, the instantaneous water removal rate is 30X0.5X60=9001! This value is then converted to the amount of water removed after dialysis.

If the dialysis time is set to 4 hours, the amount of water removed after dialysis (U
FR(tn)] is 3.600d. The signal [UF R (tn)) from the water removal amount conversion means 31 is sent to the difference calculation means 32 from the set water removal amount, and the water removal amount (UFR (!l)) set in advance by the water removal amount setting means 10 is sent. The difference between the two (e(tn) = UFR(s) - UFR(t
n)) is calculated.

The signal (e(tn)E) from the water removal amount control means 12 is then transmitted to the transmembrane pressure difference setting means 13. The transmembrane pressure difference conversion means 33 converts (tn)) into a transmembrane pressure difference (TMP), and the transmembrane pressure difference is added to the set value of the transmembrane pressure difference calculated previously to calculate the transmembrane pressure difference. The transmembrane pressure difference setting value calculating means 34 changes the set value of the transmembrane pressure difference. From the difference signal (e(tn-1)) of the exempt water amount obtained, the difference [Δe (tn) = e(tn) - e(tn-1):
1 is calculated, and then the difference between the amount of water removed obtained last time and the amount of water removed obtained the day before last [ΔΔe (tn) = Δa (tn) - Δ
e(tn-1)), and using the above calculated value and the pre-given proportionality constant (Kp), integral constant (K■), and differential constant (KD), calculate teKp-e(tn). +Kl −Δe
(tn) +KD - product e (tn) A proportional-integral-differential calculation is performed, and the amount of water removed (e (tn)) is converted to a transmembrane pressure difference (TMP (6 (tn))). Next, the transmembrane pressure difference (TMP (e(tn) )) is added to the previously calculated transmembrane pressure difference set value (TMP (tn-1)) by the transmembrane pressure difference set value calculation means 34 . Then, the added transmembrane pressure difference (TMP (tn)) − [TM
P (tn-1)]+(TMP(e(tn)) The month is set as the next transmembrane pressure difference setting value.

A set value from an initial transmembrane pressure difference setting means (not shown) may be input to the transmembrane pressure difference set value conversion means 34. In this case, when setting the transmembrane pressure difference for the first time, the converted value of the transmembrane pressure difference (TMP (e (tl
) ) ) is added. By inputting the initial setting value of the transmembrane pressure difference in this way, it is possible to prevent an abnormal transmembrane pressure difference from being set as the first or second transmembrane pressure difference setting value.

In this way, the set value of the transmembrane pressure difference is changed every time the instantaneous water removal amount is calculated periodically.

A signal (T
M P (tn)) is then converted into an analog signal by the D/A converter 35 and sent to the transmembrane pressure difference control means 15 . The rotation speed command signal generating means 36 of the transmembrane pressure difference control means 15 calculates the transmembrane pressure difference from the set value of the transmembrane pressure difference and the signals detected by the two sensors 7.8. The detected value from the calculation means 37 is compared and a proportional integral differential calculation is performed based on the difference between the two to generate a rotation speed command signal.

This rotational speed command signal is applied to the driver section of the pump 16. In other words, if the rotation speed command signal voltage is greater than the rotation speed detection signal voltage, the power supply from the driver section to the motor increases and the rotation speed of the motor, in other words, the rotation speed of the pump 5 increases; If the rotation speed command signal voltage is the same as the rotation speed detection signal voltage, the rotation speed of the motor decreases, and the rotation speed of the pump 5 is automatically controlled to follow the rotation speed command signal. Therefore, the transmembrane pressure difference can always be made to follow the value set by the transmembrane pressure difference setting means 13, and the amount of water removed can be accurately controlled.

(Effects of the Invention) As described above, the device of the present invention controls the water removal rate so that dialysis is performed in accordance with the setting value of the water removal amount setting means, so that a proper amount of water removal can be performed without causing discomfort to the patient. In addition to being able to quickly take measures against unexpected accidents, the work is simple and even beginners can easily use it.

[Brief explanation of the drawing]

1 and 2 are system diagrams showing the configuration of the present invention,
FIG. 3 is a sectional view showing the structure of the flowmeter, and FIG. 4 is a graph for explaining the present invention in detail. 3.6......First and second flowmeters 7.8......Pressure sensor 10...
......Water removal amount setting means 11...
・・・・・・ Instant water removal total calculation means 12 ・・・・・・
...Water removal amount calculation means 13 ......
...Membrane pressure difference setting means 15 ......
...Transmembrane pressure difference control means patent applicant Ri Co., Ltd.
La Shi

Claims (1)

[Claims] A flow meter that measures the flow rate of dialysate flowing through the dialysate inflow path and dialysate outflow path to the hemodialyzer, a pump installed in the dialysate outflow path, and a pressure that detects the transmembrane pressure difference between the hemodialyzer. a sensor, a water removal amount setting means for setting a total water removal amount;
An instantaneous amount of water removal calculation means that calculates the total amount of water removed from the measured values of the two flowmeters at regular intervals, and calculates the instantaneous amount of water removed from a comparison between the calculated amount of water removed and the previously calculated amount of water removed. and a water removal amount calculating means for converting the instantaneous water removal amount into a total water removal amount and calculating a difference in the total water removal amount from a comparison with the total water removal amount set by the water removal amount setting means, and a difference in the total water removal amount. transmembrane pressure difference setting means for converting the transmembrane pressure difference into a transmembrane pressure difference and adding the converted transmembrane pressure difference to the previously calculated transmembrane pressure difference set value to change the transmembrane pressure difference set value; The transmembrane pressure is controlled by comparing the transmembrane pressure difference set by the transmembrane pressure difference setting means with the transmembrane pressure difference detected by the pressure sensor and controlling the rotation speed of the pump until the deviation value between the two becomes zero. A hemodialysis apparatus comprising differential control means.