JPS60253457A - External recirculation type lung auxiliary apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Object of the Invention) The present invention relates to a liquid exchange type extracorporeal circulation mold clamping auxiliary device that regenerates and circulates dialysate.

A model lung assist device that causes less damage to the blood has come to be used as a device for extracorporeally circulating the blood of patients with respiratory failure and removing carbon dioxide components from the blood during the process. Conventionally, this type of device has been a gas-liquid model in which gas and blood are passed through a polymer lung with good gas permeability, and dissolved CO2 in the blood is removed through the membrane.

However, most of the carbon dioxide components to be removed are dissolved CO2
Since CO2 is dissolved in the blood as HOO-3 (bicarbonate ion), conventional devices that remove only dissolved CO2 have been extremely inefficient.

Recently, using a hemodialyzer for artificial kidneys, blood was passed through one side of the membrane and dialysate was passed through the other side, and the dissolved 000
2 and HCO3 to the dialysate.

JP-A-58-19265, which releases these from the dialysate as CO'2 out of the system, regenerates the dialysate, and uses it for circulation.
1'-Hemodialysis Model Artificial Lung Device" has been proposed.

However, the device disclosed in JP-A-58-19265 has the following unresolved practical problems. Namely.

Water movement occurs through the membrane between the patient's blood and the dialysate based on the pressure difference, and water enters the blood, causing various problems such as thinning of the blood and destruction of blood cell membranes. It may cause harm. In addition, the CO2 removal flow rate depends on several factors such as blood flow rate and dialysate flow rate, so it is necessary to appropriately control these factors, but this is difficult with this device.
O2 removal cannot be performed efficiently. Furthermore, it is not possible to maintain the dialysate temperature at an appropriate temperature when used for a long time.

It is difficult to confirm whether each operation and operating condition is normal, so careful monitoring by the operator is required.

This places a significant burden on the operator, such as having to carry out appropriate operating procedures.

The object of the present invention is to solve the above-mentioned problems in a fluid-type extracorporeal circulation mold clamping auxiliary device that regenerates and circulates dialysate.

(Structure of the invention) The configuration of this invention will be explained below based on the drawings.

FIG. 1 shows an example of a piping system diagram of an apparatus according to the present invention. In FIG. 1, a patient's blood is sent to a dialyzer 2 by a blood pump 1, the venous pressure and flow rate are measured in a drip chamber 3, and the blood is circulated extracorporeally through a venous pressure regulator 4. On the other hand, the dialysate is guided by the dialysate pump 5 to the dialyzer 2 through the flow meter 6, and the dialysate pressure is measured by the dialysate pressure measuring device 7 at the outlet flow path, and the dialysate pressure is measured by the dialysate pressure measuring device 7 at the outlet flow path. Heater 9
through which it is led to a dissipation tube 10 and circulated through a pH and dialysate temperature measurement 11. HOOi and dissolved CO2 in the blood move to the dialysate in contact with it through the membrane in the dialyzer 2, and the dialysate is transported to the diffusion tube lO, where the HCOi comes into contact with the sulfuric acid dehydratase contained in the dialysate. It is converted into Co2 by the use of CO2, and the large force regulator 12. Stop valve 1 vertical flow rate, control valve 14° flow meter 15. W gas such as 02, which is sent through the check valve 16, comes into gas-liquid contact with 7, and the 002
It is dissipated as. The CO2 concentration in the diffused gas is measured by a CO2 concentration meter 18. Further, a buffer solution 19 for adjusting the pH of the dialysate can be added to the diffusion tube 10 via a pinch valve 20.

Now, the blood pressure is controlled by the venous pressure regulator 4,
Further, the rotation of the blood pump l and the dialysate pump 5 is monitored by monitoring the rotation of a disk with equally spaced holes attached to the drive-overnight rotation P with a photosensor, and each Flow rate control is performed by controlling the voltage supplied to the drive motor. The temperature and pH of the dialysate are measured by the measuring section 11, and the temperature and pH are controlled by the heater 9 and the pinch valve 20, respectively. The flow rate of the added gas is monitored by a flow meter 15 such as a hot wire flow meter, and the flow rate is controlled by controlling the voltage supplied to the flow control valve 14 to adjust its opening degree.

By the way, the movement of water between the blood and the dialysate through the membrane of the dialyzer depends on the pressure difference between the blood and the dialysate, as well as the filtration pressure of the dialyzer. F) When the filtration pressure is ψ, water is removed from the blood, and when it is negative, water enters the blood.

Therefore, depending on the patient's condition, if water is to be removed from the blood, the filtration pressure is set to a certain high value, whereas if water is not to be removed, the filtration pressure is controlled to be around 0.

The amount of CO2 removed by the diffusion tube 10 also depends on the capacity of the dialyzer 2 and the diffusion tube, but also on the extracorporeal circulation blood flow, the dialysate flow rate, and the added gas flow rate.

The larger each of these amounts is, the larger the CO2 removal flow rate becomes. Therefore, efficient C
In order to remove O2 and downsize the entire device, the extracorporeal circulation blood flow, dialysate flow rate, and inert gas flow rate are appropriately controlled.

In each invention, these controls are realized using a microcomputer.

FIG. 2 shows a diagram of the control system in the apparatus of the present invention. In Figure 2, 9 extracorporeal circulation blood flow 21, venous pressure 22. Dialysate flow rate 23. Dialysate pressure 24° Dialysate temperature 25
．． Dialysate pH 26, dialysate liquid shortage 27, inert gas flow i
28. The signal from each sensor for the COz concentration 29 in the diffused gas is adjusted by the detection circuit 3o to a signal level that can be post-processed. Then multiplexer 31. After being sent to the sample and hold circuit 32, it is converted into a digital signal by the A/D converter 33 and stored in the RAM 34. On the other hand, the operation unit 35 includes a sequence switch for setting the operating mode of the device as well as a digital lv switch for setting the physical quantity to be controlled. In addition, a display circuit 36 for displaying each state quantity
and a digital μ display section 37. In addition, ROM38 stores Grodaram, which is in charge of overall control.
Based on this, the CPU 39 controls each process. On the other hand, the machine 1040 controls the boat by inputting switch data and outputting control signals. The control output signal from Ilo is applied to an interface section 41 consisting of a transistor, a solid 1-state LSU, etc., and is applied to a blood pump control circuit 42. Venous pressure control circuit 43. Dialysate pump control circuit 44. Heater control circuit 45. Blood pump l, respectively through the respective controls of the pL control circuit 6 and the inert gas flow rate control circuit 47.
Venous pressure regulator4. Dialysate pump5. Heater 9. Each control is performed by driving the pinch nozzle 2o and the flow rate control valve 14.

By the way, the filtration pressure of a dialyzer can be controlled by controlling either the venous pressure or the dialysate pressure, and in FIGS. 1 and 2, the venous pressure is controlled using a venous pressure regulator. As a venous pressure regulator, a method is shown in which a clamp head is used to adjust the degree of pressure closure of the venous blood tube, but a double front method in which a tube is provided outside the blood tube to increase or decrease the pressure inside the tube can also be used. good. The degree of pressure closure is adjusted by moving the clamp head forward, backward, and stopping, respectively, by rotating the motor forward, backward, and stopping.

FIG. 3 shows a flow chart of a microcomputer-based algorithm for controlling the filtration pressure. That is, in step S1, venous pressure data a (mmHg\) is obtained.

)of! In step S2, dialysate pressure data b(m
Step S3: calculate b-b;
In step S4, it is determined whether C is negative or not, and when it is negative, in step S5, the clamp head of the venous pressure regulator is advanced to increase the degree of pressure closure of the venous blood tube, increasing the venous pressure. If it is not negative, it is determined in step S6 whether C is smaller than (set value C1 (mmHg) - 5), and if it is "small", the process proceeds to step S5, and "
If not, it is determined in step S7 whether C is larger than (1+5), and if it is larger, the clamp head of the venous pressure regulator is retracted in step S8 to reduce the degree of pressure closure of the venous blood tube. As a stop mode, the venous pressure is lowered and the clamp head of the venous pressure regulator is stopped when the venous pressure is not high.

Next, the amount of CO2 removed by the diffusion tube is the product of the C○2 concentration in the diffused gas in the diffusion tube and the inert gas flow rate, so these two amounts are detected and processed by a microcomputer to remove CO2. This is the removal flow rate.

This CO2 removal flow rate is compared with a preset value, and if the installed value is different, the beak circulation blood flow, dialysate flow rate, or inert gas flow rate is adjusted according to the patient's condition and treatment conditions. control. For example, if the patient's blood pressure is low and only a small amount of extracorporeal blood flow can be obtained.

Increase the dialysate flow rate to reduce HCO3 and dissolved C from the blood.
Promote O2 transfer and reduce dialysate HCO”:
In order to further lower the dissolved Cog concentration, the inert gas flow rate is increased to actively remove COa in the diffusion cylinder.
Increase the efficiency of Oz removal. And vice versa.

For patients who can increase extracorporeal circulation blood flow,
In order to increase the CO2 removal efficiency, the dialysate flow rate and inert gas flow rate do not need to be increased as in the previous example, so they are controlled in this way.

FIG. 4 shows a flowchart for controlling the extracorporeal circulation blood flow, dialysate flow rate, and inert gas flow rate by a microcomputer to perform efficient (Cot removal). That is,
In step S1, input the Cot concentration data in the diffused gas in the diffusion cylinder, in step S2) input the active gas flow rate data y, in step s3f acquire the extracorporeal circulation blood flow data), and in step S4 input the dialysate The flow rate data is input, and in step S5, OO+removal flow rate Z=XX3' is calculated, and in step S6, it is determined whether 2 is smaller than the set value U.

If it is "small", it is determined in step S7 whether or not the extracorporeal circulation blood flow can be increased, and if it is "increasable", step S7 is performed.
In step S8, the blood pump is controlled to increase its flow rate, and when "increase is not possible", the dialysate pump and flow control valve are controlled in step S9 to increase the dialysate flow rate and inert gas flow rate. On the other hand, if 2 is larger than U [if J is not smaller, it is determined in step Sw whether 2 is larger than U, and it is "large".
If it is possible to reduce the extracorporeal circulation blood flow by step addition, the blood pump is controlled to reduce the flow rate in step S12, and if it is not possible to reduce the blood flow, dialysis is performed in step S13. Control the fluid pump and flow control to reduce dialysate flow rate and inert gas flow rate. On the other hand, if it is "not large" in step Sw, step S14
The current situation will be maintained.

Furthermore, when carbon dioxide components are removed from the dialysate using the diffusion tube, the pH of the dialysate increases. The dialysate contains carbonic acid and CO2.
I acid dehydratase (catalyst) that promotes the dehydration reaction that releases
carbonic anhydrase).
It is necessary to control the pH' of the dialysate in the active region of this enzyme. Therefore, in order to adjust the pH to a value close to the optimum value of 7.4 in living organisms, the amount of a pH adjusting buffer solution such as a dilute hydrochloric acid solution added is controlled.

FIG. 5 shows a flowchart for pH control of dialysate. That is, in FIG. 5, dialysate pH data is input in step SR, it is determined in step S2 whether the data is greater than or equal to the set value, and when it is "above", the pinch valve is opened in step S3 to release the pH adjustment buffer. If the value is not greater than or equal to 1 in step S2, conversely, the pinch valve is closed in step S4.

Furthermore, the dialysate temperature is controlled in the same way, and a flow chart thereof is shown in FIG. That is, in FIG. 6, dialysate temperature data is taken in in step S1, and it is determined in step S2 whether or not it is equal to or higher than a set value.If it is "V or higher", the heater is turned off in step S3.

If it is determined in step S2 that the temperature is not higher than that, the heater is turned on in step S4.

By the way, the control program stored in the aforementioned ROM can be roughly divided into a main routine and an interrupt wL routine, the flowcharts of which are shown in FIGS. 7 and 8, respectively.

In FIG. 7, first, in step SR, after performing initial settings such as clearing the RAM and clearing the output port 10,
Input the status of the sequence setting switch from step 10, stop at steps S2° to S5, and turn on the power.

Determine disinfection, preparation, and start modes, and in 7-steps S6 to SIO 1, for example, activate a buzzer when the power is turned on, or rotate the dialysate pump at a constant speed in preparation mode to keep the opening of the flow control valve constant. The process corresponding to each mode, such as predetermined control such as It also performs alarm processing in the preparation and start modes as shown in Table 1.

In the interrupt routine shown in FIG. 8, first, in step S1, the CPU immediately before the main routine interrupt occurs.
After saving and holding the register state.

In step S2, generation of other interrupts is prohibited. Next, in step S3, data from each setting switch is input, and in step S4, analog signals from each sensor and detection circuit are A/D converted. Thereafter, each mode is determined in steps 85 to S8, and processing in each mode is performed in steps 89 to Sll. That is, in the start mode of step S94, various displays are performed, the presence or absence of an alarm is checked, and the venous pressure regulator, blood and dialysate pump, heater, pinch pulp, and flow control valve are controlled. Similarly, step Sl
In the stop mode of O, various displays are performed, and in the preparation mode of step Sll, various displays are performed, the presence or absence of an alarm is checked, and the venous pressure regulator and heater are controlled. After performing these processes, the previously saved contents of the CPU register are restored in step Sν, and after canceling the interrupt prohibition in step S13, the program returns to the address of the next instruction where the interrupt occurred in the main routine. This interrupt routine also plays the role of a timer, so it occurs periodically, such as every 0.5 seconds or 1 second. Included in the injection routine.

Table 2 shows the input/output status in each mode detailed above.

Table 2 (Experiment example) In the apparatus shown in Figure 1, a dialyzer made of 7μ low hollow fiber with a membrane area of 2.5 m was used, and the dissipation cylinder was a cylinder type with a side of 130 m and a height of 200 m. An experiment was conducted using . A bicarbonate ion-rich solution obtained by adding bicarbonate ions to a general dialysate was used as a blood substitute, and 16 mg of 1.6 glC carbonic anhydrase (carbonic anhydrase), which is a general dialysate, was added to the sending solution. I used things. Moreover, an O-5 normal hydrochloric acid solution was used as a pH adjustment buffer, and 100% 02 was used as an inert gas. The filtration pressure, COa removal flow rate, and dialysate pH were set at Ommng, 50 me/min, and 7.4, respectively.

At this time, the extracorporeal circulation blood flow, dialysate flow rate, and inert gas flow rate are approximately 200 m (g/min) each.

5oome/min and 20g/min.

Filtration pressure, 00g removal flow rate and dialysate pH were each 0.
~5mmHg, 30~7ome/min and 7.2~
It was controlled within the range of 7.5.

Table 3 illustrates data on the CO2 partial pressure and HCOM concentration of the blood and dialysate at the inlet and outlet of the dialyzer and the CO2 removal flow rate from the emission cylinder in this experiment.

(Clinical example) The clinical trial was conducted using the same equipment as in the previous example. The patient's preclinical blood OOz partial pressure was 66. amm'Hg, HCO3 concentration was 39.1 mEq 7'e, and pH was calculated to be 7.390. The dialysate was a general dialysate 1.6e with 20mg of carbonic anhydrase added, the pH adjustment buffer was a 0.5N hydrochloric acid solution, and the inert gas was 100%. 02 was used respectively.

Then, the filtration pressure, CO2 removal flow rate, and dialysate pH were set to OmmHg, 20 me/min, and 7.4, respectively.

At this time, the extracorporeal circulation blood flow is 3ome/mj-n at the start.
, maximum 80 m e/m'x n, average about 5 ome
/m4n, and the dialysate flow rate and inert gas flow rate were approximately soome/mj-n and 25e/m1n, respectively. And the filtration pressure and dialysate pH are 0 to 5, respectively.
mmHg and 7.2 to 7.6, and the maximum CO2 removal flow rate was 4.3 m (17 min).

The partial pressure of CO2 and HC in the patient's blood after 1 hour of clinical treatment
03 concentration is 43.6 mmHg and 26, om, respectively.
It decreased to Eq/e. The pH of the blood at this time is 7.
．． The calculated value was 398, which was extremely close to the ideal value.

(Effects of the Invention) As detailed above, according to the present invention, in a liquid exchange type extracorporeal circulation pulmonary assist device that regenerates and circulates dialysate, venous pressure, extracorporeal circulation blood flow, dialysate By controlling the flow rate and inert gas flow rate to the optimum state according to the condition of the patient, etc., the filtration pressure and the CO2 removal flow rate can be controlled.

Dialysate temperature and pH can also be precisely controlled.

Safe and efficient operation and management of the device can be extremely facilitated, and the burden on operators and patients in hospitals can be significantly reduced.

[Brief explanation of drawings]

Fig. 1 is a piping system diagram of the device according to the present invention, Fig. 2 is a block diagram of its control system, Fig. 3 is a flowchart for controlling F' overpressure, and Fig. 4 is a flowchart corresponding to the set value of the CO2 removal flow rate. Flowchart for controlling extracorporeal circulation blood flow, dialysate flow rate, and inert gas flow rate. 5 and 6 are flowcharts for controlling the dialysate pH and temperature, respectively, and FIGS. 7 and 8 are flowcharts for the main routine and interrupt routine of the control program, respectively. 1... Blood pump 2... Dialyzer 3... Drip chamber 4... Venous pressure regulator 5... Dialysate pump 6...
Flow rate needle wound liquid) lo... Diffusion tube 14... Flow rate control valve 15... Flow meter (Inert force numeral 17... Inert gas 18... CO+1 concentration meter 34
・、・RAM 38...ROM39-- 、CPU
4o--・Engineering 1041... Interface section 42... Blood pump control circuit 43... Venous pressure control circuit 44... Dialysate pump control circuit 47... Inert gas flow rate control circuit Patent applicant Stock Company Sanyo Electric Manufacturing Figure 1

Claims (1)

[Claims] The patient's extracorporeally circulating blood and dialysate are brought into contact with each other through a membrane in the dialyzer, and the carbon dioxide component in the blood is transferred to the dialysate, which is then exchanged with an inert gas in a diffusion tube. C, O in gas-liquid contact
In a lung assist device, the dialysate is dissipated and removed as t, and the dialysate is regenerated and used for circulation. An extracorporeal circulation mold clamping auxiliary device characterized by comprising means for controlling the filtration pressure of a dialyzer and means for controlling the CO2 removal flow rate.