JPH0113384B2 - - Google Patents

Description

Detailed Description of the Invention (Object of the Invention, Field of Industrial Application) The present invention relates to an automatic dialysis device used when performing hemodialysis using a positive pressure method.
Used for labor saving.

(Prior art) Hemodialysis, which is performed using an artificial kidney device (dialysis device), is used to purify blood by eliminating waste products from the body or taking in what is needed instead of the kidneys when the human body suffers from kidney failure. It is widely used to carry out.

Figure 1 shows an example of a conventional dialysis device.
This is based on the positive pressure method. In Figure 1, cannulae 1a and 1b are inserted into the blood vessels of the limbs of body A.
Puncture the hole and use it as an entrance/exit for extracorporeal circulation of blood. The blood pump 2 supplies a constant flow of blood flowing out from the cannula 1a to the dialyzer 3, and the constrictor 4 creates a stenosis in the tube 5 to generate positive pressure in the blood within the dialyzer 3. An air chamber 6 is installed at the blood inlet and outlet of the dialyzer 3.
a, 6b and pressure gauges 7a, 7b are provided as a guide for knowing the ultrafiltration pressure. A supply path 8a and a discharge path 8b are connected to the dialyzer 3, and a separately prepared dialysate is supplied thereto. To perform hemodialysis using this conventional dialysis device, after rotating the blood pump 2, the diaphragm 4 is squeezed to generate positive pressure, and the pressure gauges 7a, 7
Check b and adjust the ultrafiltration pressure to an appropriate level.

By the way, the main function of the kidneys is to produce urine, and most of this urine is water, so in hemodialysis, it is necessary to remove water from the blood, so-called water removal. This will be an important issue. Water in the body moves into the blood through the cells, between cells, and blood vessels, but it is necessary to remove water at a rate commensurate with this transfer rate, and this rate varies depending on the patient. Even in the same patient, the symptoms change from day to day, making it extremely difficult to understand. The factors that determine water removal include ultrafiltration pressure, dialysis area of the dialyzer, type of membrane, dialysis time, blood flow rate, and osmotic pressure difference between dialysate and blood.

Among these factors, the area of the dialyzer and the type of membrane of the dialyzer are determined by the dialyzer to be used, and the most suitable dialyzer may be selected from among various dialyzers. The osmotic pressure difference between dialysate and blood actually does not work very effectively for water removal. The longer the dialysis time is, the greater the amount of water removed, but since the patient must be restrained during the dialysis and the person caring for the patient must monitor and perform necessary treatment, it is better to keep the dialysis time short.
Therefore, in actual hemodialysis, it is necessary to adjust the ultrafiltration pressure and blood flow rate to make the water removal rate as fast as possible, and to remove the desired amount of water within a certain amount of time. . To achieve this, it is a major premise that a stable extracorporeally circulating blood volume can be obtained from the patient, but each patient has a limit to this blood flow rate, and rapid water removal can lead to a lack of internally circulating blood volume. It is extremely difficult to obtain a stable extracorporeally circulating blood volume over a long period of time due to the resulting drop in blood pressure or troubles with the blood inlet/output device (blood access) for performing extracorporeal circulation. In particular, patients who have experienced a drop in blood pressure due to water removal,
In addition to causing unpleasant symptoms such as vomiting, convulsions in the limbs can last for a long time if left untreated, and in the worst case scenario, it can even lead to death due to shock, so extreme care must be taken to prevent a drop in blood pressure. However, if the water removal rate is made too slow for fear of blood loss, water will not be removed sufficiently and will remain in the body, placing a heavy burden on the circulatory system.

Conventionally, in order to speed up water removal and prevent a drop in blood pressure, even in patients who are in a stable phase after long-term dialysis, treatment was performed every 15 to 30 minutes immediately after the start of dialysis, and every 30 to 60 minutes midway through dialysis. Every time, 15~ before the end
Blood pressure is measured every 30 minutes on a regular basis, and patients who have just started dialysis, children with low circulating blood volume,
Also, in patients who are prone to rapid drop in blood pressure or coronary insufficiency due to strong arteriosclerosis due to old age or diabetes, blood pressure measurements must be performed more frequently than regular blood pressure measurements, and the results of each measurement may be affected. The water removal speed is adjusted accordingly. Normally, these tasks are performed by nurses, who are busy with the above-mentioned frequent blood pressure measurements and adjusting the water removal rate.
Furthermore, in the event that a patient's blood pressure drops, the patient will be busy with follow-up treatments such as fluid replacement, drug injection, warm compresses, and waste disposal. 4 to 5 nurses
Considering the current situation in which nurses are responsible for hundreds of patients, these tasks account for a very high proportion of the total nursing work, resulting in heavy labor for nurses.

In this way, conventional dialysis machines rely on the input of nurses and others for the multiple tasks necessary to perform hemodialysis under good conditions, which naturally increases the chances of human error and increases the Problems included the heavy labor and shortage of women and the increasing cost of hemodialysis.

In order to alleviate these difficulties to some extent, for example, as disclosed in JP-A-51-51192 and JP-A-50-141898, a pressure sensor is installed in the blood circuit to detect the blood pressure on the upstream side of the blood pump. A device has been proposed that is equipped with a detector that continuously records the maximum and minimum values of blood pressure, and if the pressure exceeds a certain value, an alarm signal such as an alarm bell is sent out. has been done. According to this dialysis machine, there is no need to directly measure the blood pressure of the patient, which reduces the workload, but since it merely records the blood pressure and sends out an alarm signal, it is difficult to handle abnormal situations. The complicated work of adjusting the water removal rate to prevent a drop in blood pressure and return it to a normal value must be done manually by a nurse or the like, which has the disadvantage that it does not lead to significant improvements in work.

(Objective of the Invention) The present invention was achieved as a result of long years of research by the inventor in view of the above-mentioned circumstances, and eliminates most of the frequent blood pressure measurements of patients and the adjustment of the water removal rate each time. Therefore, it is an object of the present invention to provide an automatic dialysis device that can significantly save labor.

(Structure of the Invention) The present invention is an apparatus for performing hemodialysis using a dialyzer using positive pressure on the blood circuit side, which includes a blood pump for feeding blood to the dialyzer, a pressure measuring section, and a predetermined pressure value. a pressure sensor, which is installed upstream of the blood pump, measures the pressure of the blood on the upstream side, and outputs a detection signal when the measured pressure falls below the set pressure. a positive pressure regulator that creates a constriction in the blood circuit on the downstream side of the dialyzer to generate ultrafiltration pressure based on the positive pressure in the dialyzer, and the positive pressure regulator based on a detection signal from a pressure detector. This invention relates to an automatic dialysis apparatus characterized in that it is equipped with a positive pressure control means for canceling the stenosis caused by the ultrafiltration pressure and reducing or zeroing the ultrafiltration pressure.

(Example) First, the principle of the present invention will be explained.In place of conventional blood pressure measurement during dialysis, in the present invention, the pressure of blood on the upstream side of the blood pump 2 is detected by a pressure detector.

That is, the second explanation for explaining the principle of the present invention
In the figure, the inside of the venous blood vessel B normally has a positive venous pressure b, and when blood is sucked by the blood pump 2 through the cannula 1a and tube 5a punctured into the venous blood vessel B, the cannula 1a causes A pressure drop c occurs which is approximately inversely proportional to the effective area of the cannula 1a and approximately proportional to the blood flow rate, ie the rotational speed of the blood pump 2. Therefore, the pressure of the blood within the tube 5a is (b-c), which is generally a negative pressure and remains approximately constant during normal dialysis. As water removal progresses, the amount of blood in the blood vessels decreases, but blood pressure is normally maintained so as not to drop due to arterial contraction. However, when water is removed beyond the capacity of blood vessels to contract, venous pressure b decreases,
The pressure becomes zero or negative. Therefore, the pressure (b-c) inside the tube 5a tilts further toward the negative pressure side, so when this pressure falls below a certain value, the ultrafiltration pressure is reduced or zeroed to stop water removal.
It is possible to prevent a drop in blood pressure throughout the body.

An embodiment of the invention is shown in FIG. In the figure,
The air chamber 6a is provided in the middle of a tube 5a that connects the cannula 1a and the blood pump 2, and a pressure detector 9 is connected to the air chamber 6a via a pressure monitor tube 5e. As shown in FIG. 4, this pressure sensor 9 has a measuring needle 11 that moves on a scale plate 10 having graduations ranging from appropriate negative pressure to positive pressure in accordance with the pressure applied by the pressure monitor tube 5e. It also has a first setting hand 12, a second setting hand 13, a first indicator light 12, and a second indicator light 13a. The first setting hand 12 and the second setting hand 13 can be set at any position on the scale plate 10, and each setting position and the measuring needle 1 can be set at any position on the scale plate 10.
1 and the first detection signal R respectively.
Alternatively, the second detection signal S is output, and the first indicator light 12a or the second indicator light 13a is turned on. Tube 5 used here
Since negative pressure is applied to a and 5e, it is preferable to use a material that is hard enough not to be deformed by negative pressure so that the pressure can be detected accurately.

The dialyzer 3 is a conventional and well-known device, and the blood pump 2 is connected to the blood inlet through a tube 5b, and the blood pump 2 is connected to the blood outlet through a tube 5c to an air chamber 6b and a pressure gauge 7b. It is connected to cannula 1b via tube 5d. At a portion of the tube 5d near the outlet of the dialyzer 3, there is a positive pressure regulator 1 for pressing the tube 5d to create a stenosis or releasing the pressure to eliminate the stenosis.
4 is installed.

In FIG. 5, two guide brackets 16 and 17 are attached to an L-shaped pedestal 15, and a slide piece 1 is inserted into slide holes 16a and 17a provided coaxially in both guide brackets 16 and 17.
8 is slidably inserted. The right side of the slide piece 18 has a small diameter rod part 18a, and the tip of the rod part 18a is provided with a screw and is fixed to a connecting tool 19 with nuts 20, 20, and this connecting tool 19 has a pin 21. The plunger 22a of the solenoid 22 is connected to the plunger 22a of the solenoid 22 fixed to the pedestal 15 via the solenoid 22. The left side of the slide piece 18 is a pressing portion 18b having a substantially triangular cross section for pressing the tube 5d to create a stenosis. A compression spring 23 and washers 24a and 24b that receive both ends of the compression spring 23 are fitted onto the rod portion 18a, and the slide piece 18 is urged leftward by the compression spring 23.

Referring also to FIG. 6, a guide screw 26 is mounted coaxially on the left side of the pressing part 18b, and is screwed into a screw hole of a bracket 25 fixed to the pedestal 15 and fixed by a lock nut 26a. , there is a head 27 in the screw hole of the guide screw 26.
A threaded rod 27 having a diameter a is screwed together. Pressing part 1
The above-mentioned head 27a fits into the recess 28a provided in the center of the pedestal 28 disposed opposite to the pedestal 8b, and the head 27a
A stopper 29 having a hole smaller than the outer diameter of the screw rod 27 is loosely fitted onto the threaded rod 27 and fixed to the pedestal 28. Two guide bars 30, 30 are attached to the pedestal 28 in parallel with the threaded rod 27. Rotation of the pedestal 28 is prevented. 27b is a knob for rotating the threaded rod 27.

This positive pressure regulator 14 includes a pedestal 28 and a pressing part 18.
By sandwiching the tube 5d between the tube 5d and rotating the knob 27b to move the pedestal 28 in the left-right direction in FIG. 5, it is possible to create a constriction in the tube 5d and adjust its size. When the solenoid 22 is energized in this state, the plunger 22a is attracted and moves the slide piece 18 to the right against the compression spring 23 via the pin 21 and the connector 19, so that the pressure on the tube 5d is released. Stenosis disappears. When the solenoid 22 is de-energized, the slide piece 18 is urged by the compression spring 23 and returns to its original state, and the same constriction is created in the tube 5d again. Tube 5b used here
The tube 5d is preferably thick in order to reduce the flow rate of blood flowing into the dialyzer 3 and evenly distribute the blood inside the dialyzer 3, and the tube 5d is easy to create a stenosis and connect with equipment. A soft material is preferable.

Referring again to FIG. 3, electromagnetic on-off valves 33,
34 are provided. A well-known flow rate adjustment valve 35 and a flow meter 36 are connected to the upstream side of the electromagnetic on-off valve 33 in the supply path 31.
A bypass path 38 provided with an electromagnetic on-off valve 37 is connected in parallel with the flow meter 36 . The electromagnetic on-off valves 33, 34, and 37 used here are
It has a well-known structure that opens and closes the flow path when turned off, and is preferably made of chemically resistant material such as stainless steel. The bypass path 38 is used when exchanging the dialysate in the dialyzer 3 in a short time, and preferably has a flow path resistance as low as possible.

Next, the detection signal of the pressure detector 9, the blood pump 2, the positive pressure regulator 14, and the electromagnetic on-off valves 33, 34,
The relationship with the operating state of No. 37 will be explained. While normal dialysis is being performed, there is no detection signal from the pressure detector 9, the blood pump 2 rotates at a constant rotation speed, and the solenoid 22 of the positive pressure regulator 14 is turned off to create a regulated stenosis. A positive pressure is generated, the electromagnetic on-off valves 33 and 34 are opened, and the electromagnetic on-off valve 37 is closed, and a constant flow of dialysate is supplied to the dialyzer 3, which is a water removal state. When the pressure decreases and the first detection signal R is output by the first setting needle 12, the solenoid 22 is turned on, the stenosis is released, the ultrafiltration pressure decreases to near zero, and the electromagnetic on-off valve 3
3 and 34 are closed and the supply of dialysate is stopped, resulting in a water removal stop state. This water removal stop state is
It is held even if the pressure drops further below the set value of the first setting hand 12, and it is held for a certain period of time (for example, 10 minutes) even if the pressure rises immediately and the first detection signal R is no longer output. The system is designed to prevent chattering and ensure patient safety. There are two ways to start counting this certain period of time: after the first detection signal R is output and after the output ceases. When water removal is stopped, water is not removed, but substances are moved by osmotic pressure, so it is preferable to replace the dialysate at appropriate intervals. Therefore, the electromagnetic on-off valves 33, 34, and 37 are opened for a short time approximately once every minute. The shorter the time required to replace the dialysate, the better; this depends on the priming amount on the dialysate side of the dialyzer 3 and the flow rate at the time of replacement, and is about 1 second to several seconds.

Now, when water removal is stopped, the blood pressure increases and the first detection signal R is no longer output, and after a certain period of time has passed, the solenoid 22 is turned off and the electromagnetic on-off valves 33 and 34 are opened, and normal dialysis is started. resume.

By the way, it is conceivable that the pressure suddenly decreases due to some abnormality during dialysis. For example, the tip of the cannula 1a may stick to the inner wall of a blood vessel, resulting in a state where blood flow is occluded. In this case, the pressure inside the cannula 1a and the tube 5a drops rapidly, and if this state is left for a long time, it will damage the inner wall of the blood vessel, so it is necessary to stop the blood pump 2. The second setting needle 13 is for detecting this pressure drop, and in addition to stopping the blood pump 2 based on the second detection signal S caused by this, the second setting needle 13 is also used to stop the blood pump 2 and to
The configuration is such that each device such as 3, 34, etc. operates on the safe side and also generates an alarm sound, lights up an indicator light, etc. This second detection signal S allows the nurse to know that an abnormality has occurred, and it becomes possible to take prompt and appropriate measures to prevent accidents.

A method of using the apparatus configured as described above will be explained. First, the electromagnetic on-off valves 33 and 34 are opened and the electromagnetic on-off valve 37 is closed to appropriately adjust the flow rate of the dialysate using a well-known method. When the blood pump 2 is stopped, the pressure detector 9 detects the static shunt pressure P ₁
Measure. P ₁ is a positive pressure, usually several tens of mmHg. The order of adjusting the dialysate and measuring P ₁ may be reversed or may be performed simultaneously. Next, the blood pump 2 is rotated and its rotational speed is set to a blood flow rate necessary for the dialysis, and at this time the shunt pressure P ₂ during circulation is measured by the pressure detector 9. _P2 is the value obtained by subtracting the pressure drop caused by the cannula 1a from _P1 , and is usually a negative pressure. The first setting needle 12 of the pressure detector 9 is set to a value of P ₃ =P ₂ −P ₁ and the second setting needle 13 is set to a value of P ₄ =P ₃ −(50 to 100). Therefore, P ₃ is the shunt pressure during circulation
The static shunt pressure P ₁ is lower than P ₂ , and P ₄ is 50 to 100 mmHg lower than P ₃ . Next, the constriction of the tube 5d is adjusted using the positive pressure regulator 14, and the ultrafiltration pressure is set using a well-known method while observing the pressure gauge 7b. For example 2.4
of water in 6 hours, dialyzer 3
If the UFR is 4 ml/hr/mmHg, the required ultrafiltration pressure will be 100 mmHg. Also, of course,
Measure and test the patient's blood pressure and other conditions.

The device adjusted as above is the blood pump 2
Normal dialysis is performed by a constant amount of blood circulation and ultrafiltration pressure, and water removal also progresses. As water removal progresses, the patient's blood volume decreases, but blood pressure is maintained to some extent by constriction of the arteries. However, as water removal progresses further and the pressure of blood in the blood vessel puncturing the cannula 1a decreases, the pressure in the tube 5a also decreases, and the measuring needle 11 of the pressure detector 9 moves downward, causing the first Setting needle 1
If it becomes equal to the set value P ₃ of 2, the first detection signal R
is output. When the first detection signal R is output,
The solenoid 22 is turned on, the constriction of the tube 5d is released, and the ultrafiltration pressure is reduced to near zero. At the same time, the electromagnetic on-off valves 33 and 34 are closed, and the supply of dialysate is stopped, so that water removal does not proceed. Stop. Also, at this time, the first indicator light 12a lights up. In this state where water removal is stopped, the electromagnetic on-off valves 33, 34, and 37 are opened for several seconds about once every minute, allowing a large flow of dialysate to flow, and the dialysate in the dialyzer 3 is drained for a very short period of time. I will be replaced.

When the water in the patient's body moves into the blood and the blood volume increases and the pressure in the blood vessels is restored, the first detection signal R is no longer output, and if a certain period of time has elapsed, the solenoid 22 is turned off. Solenoid on-off valve 3
3 and 34 are opened, and the electromagnetic on-off valve 37 is closed to resume normal dialysis. Therefore, the patient does not experience any adverse drop in blood pressure and can continue normal dialysis. If the pressure inside the tube 5a suddenly decreases due to some abnormality during dialysis, the second setting needle 13 detects this and outputs the second detection signal S, stops the blood pump 2, and issues an alarm sound and display. A light will alert the nurse.

Therefore, water removal can be safely performed as initially set without having to frequently measure the patient's blood pressure or adjusting the ultrafiltration pressure and water removal rate each time. . Further, as water removal progresses, the concentration of blood increases, fluid resistance within the cannula 1a increases, and pressure drop increases. Therefore, the pressure within the tube 5a is further reduced, and the first detection signal R is output before the pressure of blood within the blood vessel reaches zero, which is safer. If this increase in blood concentration cannot be expected depending on the patient, or if you want to have a margin on the safety side due to various circumstances, set the first setting needle 12 to P _3.
It is sufficient to set it to a value of about 90 to 95% of . Also,
To find P ₃ , we actually measured the circulating shunt pressure P ₂ and the resting shunt pressure P ₁ and calculated the difference between them.
As a simple method, calculate the pressure drop using blood hematocrit value, blood flow rate, etc. as parameters for cannulae of various inner diameters and make a list or graph, and then use the list or graph to calculate P during dialysis. You can also ask for ₃ . The inventor of the present invention has implemented both methods for determining P ₃ and has confirmed that they almost match.

In this embodiment, as described above, the pressure detector 9 is one that obtains a detection signal by moving the setting needle on the scale plate. It may be any device that outputs a detection signal when the pressure becomes lower than the set pressure, and is not limited to the example shown. For example, the measured pressure may be converted into an electrical signal using a strain gauge or a semiconductor, and the electrically set value and the measured pressure signal value may be electrically compared to output a detection signal. Further, at this time, it is also possible to directly attach the sensor portion of the pressure detector 9 to the tube 5a, cannula 1a, blood pump 2, or the like.

In this embodiment, a pressure gauge 7b having an upper limit setting needle is used, and is configured to output necessary signals such as stopping the blood pump 2 when a pressure higher than the set pressure occurs due to some abnormality. It's okay.

In addition to this example, if a heater is provided to heat the dialysate, the heater should be turned off when the dialysate supply is stopped, or the heater should not be turned off and the dialysate should be dialyzed in order to prevent overheating of the dialysate. A bypass circuit may be provided in which the fluid flows outside the dialyzer 3.

According to the above-mentioned automatic dialysis apparatus, there is no need to frequently measure the blood pressure of a patient or adjust the water removal rate each time, which is required in the past, resulting in significant labor savings. Also,
A drop in blood pressure due to excessive water removal is prevented, and the water removal speed is sufficiently increased to the limit to achieve high efficiency in both clearance and water removal. In the event of an abnormality such as a problem with the cannula 1a, the blood pump 2 is stopped to ensure the safety of the patient, and the degree of monitoring can be relaxed, and the shunt can be protected and its lifespan can be extended. Even when water removal is stopped, the dialysate is replaced at regular intervals, so dialysis other than water removal continues as usual. Furthermore, since the time required to replace the dialysate is extremely short, almost no water is removed during the replacement. Naturally, this device can also be used to remove a small amount of water, and in that case, stable dialysis and water removal can be performed safely.

In the normal dialysis process, the ultrafiltration pressure may be adjusted according to changes in the pressure inside the tube 5a, that is, the pressure detected by the pressure detector 9. For example, a microcomputer may be used to store in advance a program for obtaining the optimal ultrafiltration pressure based on data regarding the patient, data regarding equipment used in the device, pressure values in the tube 5a, and various data. , a servo motor, a servo valve, etc. may be operated according to the pressure within the tube 5a to perform the safest and most efficient dialysis.

(Effects of the Invention) According to the present invention, since a pressure detector for measuring blood pressure is provided upstream of the blood pump, that is, in the middle of the blood circuit near the body, the pressure detector can detect blood pressure fluctuations of the patient. Continuous sensing is possible, which eliminates the need for frequent blood pressure measurements on the patient as in the past.

Further, according to the present invention, the positive pressure regulator obtains the required ultrafiltration pressure by constricting the blood circuit on the downstream side of the dialyzer, and the pressure detector has a predetermined pressure value setting section. Moreover, when the measured pressure falls below the set pressure, a detection signal is output, and based on this detection signal, the stenosis caused by the positive pressure regulator is released. The ultrafiltration pressure then automatically decreases or becomes zero, and the water removal speed is adjusted, eliminating the need for troublesome manual water removal adjustment work and preventing a drop in blood pressure due to excessive water removal. As a result, the water removal rate can be sufficiently increased to obtain high efficiency.

Therefore, it has many practical effects, such as reducing patient detention time by shortening dialysis time, increasing patient safety by reducing the occurrence of human error, and significantly reducing dialysis costs by saving labor and shortening time. has.

[Brief explanation of drawings]

Figure 1 shows an example of a conventional dialysis machine, Figure 2 shows an example of a conventional dialysis device.
The figures are a diagram showing a blood vessel and a cannula for explaining the principle of the present invention, FIG. 3 is a diagram showing an embodiment of the present invention, FIG. 4 is a front view showing an embodiment of the pressure detector, and FIG. 6 is a front view showing an embodiment of the positive pressure regulator, and FIG. 6 is a partially enlarged view taken in the direction of the arrow in FIG. 5. A...Main body, 1a, 1b...Canyule, 2...
...Blood pump, 3...Dylyzer, 5d...Tube (blood circuit), 5e...Pressure monitor tube (pressure measuring section), 9...Pressure detector, 10...Scale plate (predetermined pressure value setting section) ), 11... Measuring needle (pressure measuring section), 12... First setting needle (predetermined pressure value setting section), 14... Positive pressure regulator.

Claims (1)

[Scope of Claims] 1. A device for performing hemodialysis using a dialyzer using positive pressure on the blood circuit side, comprising: a blood pump that sends blood to the dialyzer; a pressure measuring section and setting of a predetermined pressure value. has a department;
a pressure detector installed upstream of the blood pump to measure the pressure of the blood on the upstream side and output a detection signal when the measured pressure falls below a set pressure; downstream of the dialyzer; a positive pressure regulator that creates a stenosis in the blood circuit on the side and generates ultrafiltration pressure by the positive pressure in the dialyzer; An automatic dialysis device comprising: positive pressure control means for reducing or zeroing the external filtration pressure;