JPS632630B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dialysis system, and more particularly to a single needle dialysis system using a single needle.

A conventional single-needle dialysis system includes a blood circuit from the single needle through a blood pump, a blood chamber of a dialyzer, and a drip chamber and back to the single needle, and a dialysate circuit in which dialysate passes through the dialysate chamber of the dialyzer. When performing dialysis with this dialysis system, the clamp on the blood suction side is opened and the clamp on the blood return side is closed when blood is sucked, and in this state the blood pump is operated to send blood to the dialyzer. Blood passes through the dialyzer and enters the drip chamber. At this time, the pressure inside this drip chamber is measured. When the pressure inside this chamber reaches a set pressure H corresponding to venous pressure, the blood suction side clamp is closed and the blood return side is closed. The clamp is opened. This allows blood to be returned to the patient. The pressure inside the chamber decreases due to blood return, and when it reaches the set pressure L, it returns to the initial state. Blood dialysis is performed by repeating these operations, but in conventional dialysis systems, the amount of water removed from the patient per unit time (hereinafter referred to as water removal rate) is managed by controlling the pressure inside the drip chamber, that is, the venous pressure. This is done solely through management. However, this water removal rate is affected by variations in the water removal ability of the dialyzer (approximately 20% to 30%), changes over time (approximately 20% decrease), and fluctuations in osmotic pressure (variations in extreme overpressure). Control of venous pressure alone is insufficient to control water removal rate.

Therefore, an object of the present invention is to provide a single needle dialysis system that can detect the water removal rate fairly accurately and properly suck and return blood.

According to this invention, in a single needle dialysis system having a blood circuit passing through at least a single needle and a blood chamber of a dialyzer, and a dialysate circuit passing through a dialysate chamber of the dialyzer, a blood suction side blood circuit from the single needle to the dialyzer. The actual limit is determined from the pressure difference between the blood pump installed in the dialyzer, the opening/closing means for the blood flow path provided in the blood return circuit from the dialyzer to the single needle, and the blood circuit and dialysate circuit upstream of the opening/closing means. A pressure detector that detects external overpressure, a water removal rate detector that detects the water removal rate from the difference between the intake amount and discharge amount of dialysate and outputs an electric signal corresponding to this water removal rate, and a target removal rate detector. a water removal rate setter that outputs an electric signal corresponding to the water rate; an arithmetic circuit that calculates an optimal overpressure limit based on the output signals of the water removal rate detector and the water removal rate setter; and the pressure a comparator that compares the actual limit overpressure with a pressure obtained by adding or subtracting a pressure width set by a pressure width setting device to the optimum limit overpressure based on the output of the detector and the arithmetic circuit; , means for controlling the blood pump and the closing means to fill and return blood into the blood circuit in accordance with the output of the comparator;
A single needle dialysis system is provided comprising:

According to the present invention, in the single needle dialysis system, the pressure of the blood circuit and the dialysate circuit is transmitted to the pressure detector using gas as a medium.

According to this invention, in the single needle dialysis system, a pressure detector is connected to the blood return side of the blood circuit.

According to this invention, in the single needle dialysis system, a pressure detector is connected to the dialysate suction side of the dialysate circuit.

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, a connector 12a of a Y-shaped single needle 11 as shown in FIG. 2 is connected to a blood suction port 14a of a blood chamber of a hollow type dialyzer 14 via a tube 13 made of vinyl chloride resin.
A blood pump 15 is provided in the middle of the tube 13. A blood discharge port 14b of this dialyzer 14 is connected to a drip chamber 17 via a tube 16 made of vinyl chloride resin. Drippuchiyamba 1
Blood discharge port 7 is made of vinyl chloride resin tube 18
Connector 12b of single needle 11 through
connected to. An automatic clement 19 is provided in the middle of the tube 18 to drain and stop the blood in the tube 18. Said single needle 1
1. A blood circuit 25 is formed by the blood chamber of the dialyzer 14, the drip chamber 17, and the tube. On the other hand, the dialysate supply device 20 is connected to the inlet 22a of the dialysate chamber of the dialyzer 14 via a tube 21 made of vinyl chloride resin. Incidentally, a flow meter 23 for measuring the amount of supplied dialysate and an air chamber 24 for measuring pressure are provided in the middle of the tube 21. Dialysate outlet 2 of dialyzer 14
2b is connected via a tube 26 made of vinyl chloride resin to a flow meter 27 for measuring the amount of dialysate to be discharged.
The circuit through the dialysate chamber of the dialyzer 14 forms a dialysate circuit 28 .

The drip chamber 17 and the air chamber 24 are connected to a differential pressure sensor 31 via tubes 29 and 30 made of vinyl chloride resin. The output terminal of this differential pressure sensor 31 is connected to a comparator 3 via an amplifier 32.
It is connected to one input end of terminals 3 and 34. Comparator 3
The other input end of 3 is connected to a signal source 35 of a reference signal corresponding to the maximum allowable differential pressure (for example, 500 mmHg) determined by the withstand pressure of the dialysis membrane. The other input terminal of the other comparator 34 is connected to the optimum limit overpressure setting circuit 36.
connected to. This optimum limit overpressure setting circuit 36
A counter 37 that counts the difference in flow rate between the flowmeters 20 and 27 (for example, counts in units of one minute) and a water removal rate measuring circuit 38 that measures the amount of water removed per unit time, that is, the water removal rate from the count value of this counter 37.
Measured value of measurement circuit 38 and water removal rate setting circuit 4
8, and an arithmetic circuit 39 that calculates the optimum overpressure limit based on the target water removal rate set by 8.

The output end of the comparator 33 is connected to an automatic cleanser release relay drive circuit 40. The output end of the comparator 34 is connected to the relay driving circuit 40, the automatic drainage opening/stopping timer circuit 41, and the relay driving circuit 42 for automatic drainage closing and blood pump driving. Further, a pressure width setting device 43 is connected between the other input end and the output end of the comparator 34.
The output terminals of the relay drive circuits 40 and 42 are connected to the relay 4.
4 and 45, respectively. Normally closed and normally open contacts 44a and 44b of relay 44 are connected to automatic cleanser drive motor 46 via normally open and normally closed contacts _45a1 and 45b of relay 45, respectively. The normally open contact 45a ₂ of the relay 45 is connected to the blood pump motor 47.

When performing dialysis using the single needle dialysis system as described above, the dialysate is sent from the dialysis supply device 20 to the dialysate chamber of the dialyzer 14 via the flowmeter 23 and the air chamber 24, and the blood pump 15 pumps the dialysate into the patient's body. blood is pumped into the blood chamber of dialyzer 14 via single needle 11 and tube 13. Blood passed through dialyzer 14 enters drip chamber 17 via tube 16. At this time, since the automatic cleanser 19 is closed, the pressure within the drip chamber 17 increases as blood is pumped. The difference between the pressure within the chamber 17 and the internal pressure of the air chamber 24, ie, the actual extreme overpressure P, is detected by the differential pressure sensor 31. The differential pressure signal from the differential pressure sensor 31 is amplified by an amplifier 32 and sent to one input terminal of comparators 33 and 34. On the other hand, the output signals of the flowmeters 23 and 27, which measure the amount of dialysate supplied and the amount of discharged dialysate, respectively, are sent to a counter, for example, an up-down counter 37, and the difference between the two flow rates per unit time (for example, 1 minute) is counted. Ru. This difference signal is transferred to the water removal rate measuring circuit 38 and the water removal rate is calculated. The water removal rate signal is sent to the arithmetic circuit 39, and the optimum overpressure limit Po (for example, 200 mmHg) is calculated in this arithmetic circuit 39 from the output signal corresponding to the target water removal rate of the water removal rate setting circuit 48. A signal corresponding to the optimum overpressure from the arithmetic circuit 39 is sent to the comparator 34. This comparator 34 calculates the actual limit overpressure P and the optimum limit overpressure based on the signals from the amplifier 32 and the arithmetic circuit 39.
In this case, pressure width setting device 4 is compared with Po.
Pressure range ΔP set by 3 (e.g. 70mmHg)
is involved. That is, as shown in FIGS. 3 and 4, the actual extreme overpressure P rises from the pressure P ₁ , for example, 120 mmHg, exceeds the optimal extreme overpressure P ₀ (200 mmHg), and the difference between this pressure P ₀ and the pressure width ΔP When the added value P ₂ (270 mmHg) is reached, the output of the comparator 34 changes from L level to H level. Relay drive circuits 40 and 42 are activated in response to this output of comparator 34. As a result, the relay drive circuit 40 energizes the relay 44 and the relay drive circuit 42 de-energizes the relay 45. Therefore, relay contacts 44a, 45a and _45a2 are closed and relay contacts 44b and 45b are opened. As a result, the automatic cleanser drive motor 46 reverses to open the automatic cleanser 19, and the blood pump motor 47 stops, allowing the blood in the drip chamber 17 to be returned to the patient via the tube 18 and single needle 11. That is, blood is returned.
The automatic cleanser 19 operates for a period of time determined by an automatic cleanser open/stop timer 41 and then stops, thereby adjusting the blood return speed.

The pressure inside the drip chamber 17 decreases due to blood return, and the actual extreme overpressure P becomes P ₂ as shown in Fig. 3.
When the value decreases from P ₀ -ΔP, the output of the comparator 34 changes from the H level to the L level as shown in FIG. As a result, the relay 44 is deenergized and the relay 45 is energized, so that the automatic cleanser drive motor 46 rotates forward to close the automatic cleanser 19, and the blood pump 15 is activated to pump blood to the dialyzer 14.
sent to. Blood dialysis is performed by repeating these operations at intervals of about 1 to 2 seconds for a certain period of time. In this case, in the above example, the optimum limit overpressure
P ₀ is updated every minute.

In addition, in the above dialysis operation, the actual extreme overpressure P usually fluctuates within the range of P ₀ ±ΔP, but if it becomes higher than the allowable maximum pressure (500 mmHg), the comparator 3
The relay drive circuit 40 is actuated by the output of No. 3, and the automatic cleanser 19 is opened so that blood can be returned.

As explained above, according to the present invention, dialysis is performed based on the optimum overpressure P ₀ , and the water removal rate is actually measured by the water removal rate measuring circuit, and based on the measured water removal rate and the set target water removal rate, Optimal extreme overpressure P ₀
is corrected, so even if there are variations in the water removal ability of the dialyzer, changes over time, how much the osmotic pressure decreases, etc., the actual water removal rate will always be in the optimal state so that it matches the target water removal rate. Dialysis can be performed.

In the embodiments described above, the extreme overpressure is measured using a differential pressure sensor, but if the pressure on the dialysate side is relatively constant, only the venous pressure may be measured. In this case, there is no need to use a differential pressure sensor and a general gauge pressure type pressure sensor can be used, making the dialysis system cheaper and simpler.

In addition, since the pressure detector transmits the pressure of the blood circuit and dialysate circuit using gas as a medium, the pressure detector does not come into direct contact with blood or dialysate, is not contaminated, and is easy to handle. be.

Furthermore, since the pressure detector is connected to the blood return side of the blood circuit, stable pressure measurement can be performed without being directly affected by fluctuations such as pulsation of the blood pump compared to the suction side.

Furthermore, since the pressure detector is connected to the dialysate suction side of the dialysate circuit, changes in dialysate pressure can be detected more quickly than on the discharge side, and in some cases, the detected pressure may trigger an alarm or system operation. can also be stopped.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a single needle dialysis system according to an embodiment of the present invention, FIG. 2 is a side view of the single needle, FIG. 3 is a graph diagram showing the state of extreme overpressure, and FIG. 2 is a graph diagram showing the output of a comparator used in the dialysis system of FIG. 1. FIG. DESCRIPTION OF SYMBOLS 11... Single needle, 14... Dialyzer, 15... Blood pump, 17... Drip chamber, 19... Automatic cleanser, 20... Dialysate supply device, 23, 27... Flow meter, 24... Air remover, 2
5... Blood circuit, 28... Dialysate circuit, 31... Differential pressure sensor, 33, 34... Comparator, 35... Maximum allowable differential pressure signal source, 36... Optimal extreme overpressure setting circuit, 37...
Counter, 38... Water removal rate measuring circuit, 39... Arithmetic circuit, 40, 42... Relay drive circuit, 44, 45...
Relay, 46, 47...Motor, 48...Water removal rate setting circuit.

Claims (1)

[Scope of Claims] 1. Blood suction from the single needle to the dialyzer in a single needle dialysis system having a blood circuit passing through at least a single needle and a blood chamber of the dialyzer, and a dialysate circuit passing through the dialysate chamber of the dialyzer. From the pressure difference between the blood pump provided in the side blood circuit, the blood flow path opening/closing means provided in the blood return side blood circuit from the dialyzer to the single needle, and the blood circuit and dialysate circuit upstream of the opening/closing means. A pressure detector that detects the actual extreme overpressure, and a water removal rate detector that detects the water removal rate from the difference between the intake and discharge amounts of dialysate and outputs an electrical signal corresponding to this water removal rate. ,
a water removal rate setting device that outputs an electric signal corresponding to a target water removal rate; an arithmetic circuit that calculates an optimal overpressure limit based on the output signals of the water removal rate detector and the water removal rate setting device; Comparison of the actual limit overpressure and the pressure obtained by adding or subtracting the pressure width set by the pressure width setting device to the optimum limit overpressure based on the outputs of the pressure detector and the calculation circuit. The vessel and
A single needle dialysis system comprising means for controlling the blood pump and the opening/closing means to fill and return blood into the blood circuit in accordance with the output of the comparator. 2. The single needle dialysis system according to claim 1, wherein the pressure detector transmits the pressure of the blood circuit and the dialysate circuit using gas as a medium. 3. The single needle dialysis system according to claim 1 or 2, wherein the pressure detector is connected to the blood return side of the blood circuit. 4. The single needle dialysis system according to claim 1 or 3, wherein the pressure detector is connected to the dialysate suction side of the dialysate circuit.