JP2005084017A - Bubble amount detection system and medical device equipped with the bubble amount detection system - Google Patents

Abstract

A bubble amount detection system capable of accurately detecting a bubble amount is provided.
An ultrasonic transducer that is attached to a conduit through which liquid is fed and that oscillates ultrasonic waves and a receiving-side transducer that receives ultrasonic waves generated by the ultrasonic transducer are provided in the conduit portion. Ultrasonic detection means and bubble amount calculation means for calculating the amount of bubbles based on the detection result of the ultrasonic detection means, and data relating to the flow rate of liquid passing through the conduit and / or related to the conduit A bubble amount detection system that calculates a bubble amount by taking data as a correction parameter for calculating a bubble amount.
[Selection] Figure 1

Description

  In the present invention, the amount of bubbles of liquid flowing in a conduit, particularly the amount of bubbles containing a minute amount (minute volume) of bubbles, for example, the amount of bubbles containing minute bubbles mixed in blood or infusion fluid flowing in a conduit of a medical device is erroneously determined. The present invention relates to a bubble amount detection system capable of accurately quantifying without detection, and a medical device equipped with the bubble amount detection system.

  In medical facilities, a bubble detection device is often used so that bubbles are not mistakenly injected into a patient when transfusion or blood transfusion is performed. In that case, ultrasonic waves have been used as one of detection means so that it can be applied to non-transparent drug solutions and blood. For example, means as shown in Patent Documents 1 and 2 below are known. However, it is difficult to accurately quantify the amount of bubbles actually mixed in the liquid containing bubbles.

Japanese Utility Model Publication No.59-191662 JP 6-64016

  Conventionally, as shown in Patent Documents 1 and 2, the detection of the amount of bubbles mixed in the liquid is proportional to the time (reception level decrease time) when the reception signal when the bubbles pass decreases below a certain voltage (bubble determination value). What is calculated by a general conversion is known. However, according to this measure, since the amount of bubbles and the reception level drop time are actually poorly proportional, there is a large error between the amount of bubbles calculated from the measured value by the ultrasonic detector and the actual amount of bubbles, and accurate bubbles There was a problem that the amount could not be detected.

FIG. 7 schematically shows a mechanism for detecting bubbles from a reception level decrease time T ₁ using a conventional detection device. Conventional bubble detection is performed only by measuring a decrease time T ₁ that is a time when the waveform is decreased below a reference voltage from the waveform 4 of the ultrasonic reception level (voltage). However, the proportional relationship between the drop time T ₁ and the amount of bubbles is poor, and as described above, the bubble amount detection / determination method cannot accurately detect and determine the amount of bubbles. This is because if the bubble volume (μl) of a single bubble is large and occupies a considerable area of the vibrator, the received voltage is almost 0, so that a relatively accurate bubble amount can be detected and determined. Conversely, when the bubble volume (μl) of a single bubble is small, the correlation between the drop time T ₁ used for calculating the bubble amount and the bubble amount decreases. FIG. 6 schematically shows in what state microbubble detection is performed by a conventional bubble detection device. In the conventional bubble sensor, the width (L) of the vibrator 1 in the flow direction is as follows. The diameter of the bubble 2 of 0.3 to 1.0 μl, which is generally a microbubble, is usually about 3 mm, and the diameter of the bubble 2 is 0.83 to 1.24 mm. Since the bubble projection plane is completely contained in the transducer, the bubble volume (μl) of the single bubble is relatively small relative to the transducer area, so a large error in the detection of the amount of bubbles by the conventional method. It was the cause.

The inventor previously used (1) at least two parameters of the reception level fluctuation value or the reception level fluctuation amount increased or decreased by the bubble and (2) the reception level decrease time as the bubble amount calculation parameter. It has been proposed to detect and quantify the bubbles in the inside (Japanese Patent Application No. 2003-122616).
As a result of further investigation, the present inventor has further studied that the amount of liquid (flow velocity) flowing through the lumen of the conduit and the data related to the conduit affect the calculation of the amount of bubbles as shown in Tables 1 to 4, and further, the shape of the ultrasonic transducer (Hereinafter, each requirement is referred to as a correction parameter), and based on this technical knowledge, the correction parameter is calculated based on the bubble detection means of the above Japanese Patent Application No. 2003-122616 and other bubble amount calculation. The amount of bubbles that can be quantified more accurately compared to conventional bubble amount detection systems by correcting the influence of the correction parameters on the bubble amount calculation by adopting other bubble detection means that use parameters A detection system could be provided.

Examples of the data related to the conduit include data related to the conduit such as the diameter (inner diameter, outer diameter) and thickness of the conduit, and the material constituting the conduit. For example, as shown in FIG. 8, when the conduit is sandwiched by the ultrasonic transducer of the bubble sensor by a spring 17 or the like, the size of the conduit (inner diameter, outer diameter), the wall thickness, and further the conduit are configured. This is because the contact area of the conduit to the vibrator is affected by the material or the like as shown in FIG. Furthermore, examples of the correction parameter include the shape or size of the sensor of the ultrasonic transducer that contacts the conduit.
In the present invention, the accuracy of bubble detection can be improved by using either the liquid volume (flow rate) or the correction parameter related to the conduit, but if each of the correction parameters described above is used, more accurate calculation of the bubble volume can be achieved. It becomes possible.

  A first aspect of the present invention is an ultrasonic vibrator that oscillates an ultrasonic wave in the conduit portion where a liquid is fed into a lumen, and receives an ultrasonic wave oscillated by the ultrasonic vibrator. An ultrasonic detection unit including a side vibrator, and a bubble amount calculation unit that calculates a bubble amount based on a detection result of the ultrasonic detection unit, and relates to a flow rate of liquid passing through the conduit in the bubble amount calculation unit. A bubble amount detection system is characterized in that the amount of bubbles is calculated by taking data as a correction parameter for calculating the amount of bubbles.

According to the bubble amount detection system of the present invention, when used in medical devices that require accurate detection of the bubble amount, such as dialysis devices, infusion devices, and cardiopulmonary devices, the amount of bubbles can be detected accurately. In addition, the object of simply and accurately detecting the amount of bubbles can be achieved without complicating the detection device or adopting complicated operations.
That is, a blood pump is mounted on the dialysis device, a liquid pump is mounted on the infusion device and the heart-lung machine, and these medical devices are also provided with a flow rate (flow rate) detection means using the blood pump or the liquid pump. Therefore, by transmitting the set flow rate data obtained by the flow rate (flow velocity) detection means to the bubble amount detection system and using it as a correction parameter of the bubble amount detection system, the object can be achieved. When the flow rate (flow velocity) detection means is provided in the conduit portion of the medical device, flow rate (flow velocity) data obtained by the flow rate (flow velocity) detection means may be used as the correction parameter. Furthermore, in the dialysis device, the infusion device, and the heart-lung machine, the flow rate (flow velocity) passing through the device may be changed depending on the situation, but such a change in flow rate (flow velocity) has been performed. However, according to the bubble amount detection system of the present invention, the bubble amount can always be detected easily and accurately. The flow rate (flow velocity) data obtained by the flow rate (flow velocity) detection means provided in the medical device is transmitted to the bubble amount calculation means via an interface such as a communication circuit. In particular, when the medical device is a dialysis device, the bubble amount detection system is effective not only for detecting bubbles in a dialysis operation but also for detecting the amount of bubbles during a priming operation.

According to a second aspect of the present invention, an ultrasonic transducer that oscillates an ultrasonic wave in the conduit that is attached to a conduit through which liquid is fed into the lumen, and a reception side that receives the ultrasonic wave oscillated by the ultrasonic transducer An ultrasonic detection unit including a vibrator, and a bubble amount calculation unit that calculates a bubble amount based on a detection result of the ultrasonic detection unit; In the bubble amount detection system, the calculated bubble amount is corrected by taking in as a correction parameter.
That is, the bubble amount detection system according to the present invention includes an ultrasonic vibrator that oscillates an ultrasonic wave in the conduit that is attached to a conduit through which liquid is fed into the lumen, and an ultrasonic wave that is oscillated by the ultrasonic vibrator. In a bubble amount detection system having an ultrasonic detection means having a receiving-side transducer for receiving and a bubble amount calculation means in a detection result of the ultrasonic detection means, data relating to the conduit is calculated in the bubble amount calculation means. It was possible to provide a bubble amount detection system capable of calculating a more accurate amount of bubbles by taking it in as a correction parameter.

The calculation of the amount of bubbles using the correction parameter is performed by calculating the amount of bubbles under various conditions with respect to the correction parameter by causing a predetermined amount of bubbles (actual bubble amount) to exist in advance in the liquid to be fed. Create a table (conversion table) showing the conversion result between the calculated amount of bubbles and the actual bubble amount and use this conversion table, or use the conversion table to calculate the proportional coefficient (correction coefficient α) between the calculated value of the bubble amount and the actual bubble amount. , And by correcting the calculated value of the bubble amount using the correction coefficient α as shown in the following equation (1), the accurate bubble amount can be easily calculated.
Bubble amount = α × bubble amount calculation value (1)
The conversion table or the correction coefficient α can be stored and used in, for example, an information storage part (memory) of the bubble amount calculating means.

As the bubble amount calculation parameter in the bubble amount detection system of the present invention, for example, the time during which the reception level value (voltage change value) received by the receiving-side transducer decreases below a predetermined value (reception level decrease time), the reception level value The change rate (voltage change value) or the rate of change of the reception level value can be mentioned.
The reception level decrease time is a time (reception level decrease time) when the steady voltage value Vc drops below a certain voltage (bubble determination value), and the steady voltage Vc is an average value of voltage values when no bubble is detected. is there. In addition, the amount of change in the reception level value (voltage change value) or the rate of change in the reception level value (voltage change value) of the bubble amount calculation parameter is based on the difference between the steady voltage value Vc and the voltage that decreases when the bubble is detected. It is calculated.

Hereinafter, the bubble detection apparatus according to the present invention will be described in detail with reference to the drawings.
1. Entire Device FIG. 2 is a block diagram showing a schematic configuration of the entire bubble detection device according to one embodiment of the present invention. In FIG. 2, the oscillation circuit 5 is connected to an ultrasonic transducer 1 a sandwiched on both sides of the conduit 3. In addition, the ultrasonic transducer | vibrator 1a which an oscillation circuit communicates is a side which oscillates an ultrasonic wave, and the ultrasonic transducer | vibrator 1b with which it was attached to the conduit | pipe oppositely is a side which receives an ultrasonic wave. When the bubble 2 is present in the conduit, the ultrasonic wave oscillated from the oscillation-side transducer 1a is received by the reception-side transducer 1b in an attenuated state.
Further, the amplifier circuit 6 and the rectifier circuit 7 are in turn connected to the receiving-side vibrator 1b. The amplifier circuit 6 has a function of amplifying the voltage received by the receiving-side vibrator 1b, and the rectifier circuit 7 has a function of extracting the amplitude change. The rectifier circuit 7 is in communication with a waveform shape measuring circuit 8 that measures the time (reception level decrease time T) when the reception level value has decreased below a predetermined value. As the waveform shape measuring circuit 8, an A-D converter (Analog-Digital Converter) is usually used. The reception level decrease time T measured by the AD converter is transmitted to the bubble amount calculation means 10 that calculates the bubble amount value. In the bubble amount calculation means 10, the received reception level decrease time T, the amount of change in the reception level value (voltage change value), the rate of change in the reception level value, the set flow rate (actual flow rate) or flow velocity, and the data relating to the conduit The amount of bubbles is calculated using correction parameters such as the shape of the ultrasonic transducer (sensor) 1.

2. Waveform Shape Measurement Circuit The waveform shape measurement circuit 8 incorporates an A / D converter 14 as shown in FIG. 3, and the A / D converter 14 calculates the reception level decrease time T as follows. .
First, a bubble determination voltage Vs that is a determination criterion for the presence of bubbles is set. The bubble determination voltage Vs is determined from a voltage drop amount when a bubble having the minimum diameter (volume) that is desired to be detected passes, but is normally set to −2% to −10% of the steady voltage Vc. The time when the voltage measurement value becomes equal to or lower than the bubble determination voltage Vs (t2-t1 in FIG. 4) is the reception level decrease time T. The reception level decrease time T is an index indicating the time taken to pass through the conduit (passage time). Here, since the steady voltage VC may fluctuate depending on the contact state between the conduit and the sensor (vibrator) or the like, the voltage value of the A-D converter by the microcomputer is an average value of time that does not affect the detection of bubble passage. To do.
In order to correct the change in the steady voltage with an electric circuit, the amplifier circuit 6 may be provided with an automatic amplitude control function (AGC) amplifier. With such a configuration, the output amplitude of the amplifier is kept constant even when the received voltage varies due to the contact state of the sensor, so that it is not necessary to always average the steady voltage. As a result, the bubble determination voltage Vs can be set to a fixed voltage value, and the burden on the microcomputer can be reduced.

  The reception level decrease time T is measured by comparing the comparison signal (reception level value from the rectifier circuit 7) with the reference value VS (bubble determination voltage) by the comparator 15 shown in FIG. It is also possible by reading the time T of the bubble detection determination output 16 shown in the lower part of FIG. FIG. 4 is a schematic diagram showing the relationship between the waveform of the reception level change with time in bubble detection and the bubble detection determination output 16 calculated from the comparator.

3. Bubble amount calculation means In order to calculate the bubble amount from the reception level decrease time T obtained by the waveform shape measurement circuit, the bubble amount calculation means 10 described below is used. In addition to the reception level decrease time T, data related to the correction parameter is input to the bubble amount calculation means 10 and the bubble amount is calculated using the bubble amount detection parameter and the correction parameter. Calculation is possible.
The calculation of the bubble amount using the correction parameter can be easily performed using, for example, the conversion table 11 or the correction coefficient α. For example, when the correction coefficient α is used, if the bubble amount is X and the reception level reduction time is T, the bubble amount can be calculated easily and accurately using the equation X ∝ αT. Further, when the conversion table 11 is adopted, each correction parameter has a certain ratio between the data, so that each correction parameter prepares a conversion table only for parameter values that are frequently used and stores them in a memory, for example. If there is no description in this conversion table, it is possible to calculate the bubble amount with less data by adopting interpolation calculation using this conversion table. Further, the bubble amount detection means using the correction parameter As a reference, a reference liquid flow rate V1 and a liquid flow rate V2 at the time of use are set, and the bubble amount X is simply and easily calculated by the product of the flow rate ratio (V2 / V1) and the reception level decrease time T. be able to.

4). Bubble amount integrating means and alarm generating device Since there is a risk of causing damage if microbubbles flow into the human body over a certain amount, the bubble amount integrating means 13 is allowed to integrate the inflowing microbubbles, and the integrated value It is desirable to perform some kind of instruction / control on the alarm device or the liquid delivery device when the value reaches the set amount or more. For example, when the accumulated amount of bubbles per unit time is 0.1 ml or more, an alarm is automatically issued, and further measures such as stopping the liquid feed pump or closing the conduit are performed. As a result, the burden on health care workers is reduced.

Next, the influence of the flow rate (flow velocity) and the conduit when the bubble amount is calculated will be described below.
1. Effect of flow rate (flow rate) Using a tube shown in Table 4, a known bubble volume (0.3 to 20 μl) was mixed in the tube, and the flow rate (speed) of the liquid feed pump was set to 100 ml / min and 250 ml / An experiment was conducted to determine how the amount of bubbles affects the voltage drop amount or the drop rate when the liquid is fed while changing to min. The results of this experiment are shown in Tables 1 and 2. The experimental results show that the voltage drop rate (change rate in the table) shows a good correlation with the amount of bubbles and the passage time is greatly influenced by the flow rate, but the voltage drop rate is not affected by the flow rate as much as the passage time. It was.

2. Effect of data on conduits Introduce known 0.3 μl, 0.6 μl, 1.0 μl and 2.0 μl bubbles into each of the small, thin, thick and thin tubes shown in Table 4 Table 3 below shows the results of measuring the passage time (mS) of 10% reduction from about 1.4 V which is the reception voltage when the liquid flow rate is fixed at 250 ml / min and there are no bubbles.

前表の結果より、同じ気泡量が通過した場合であっても、所定の電圧低下率に要する通過時間（ｍＳ）は導管に関するデータの影響を大きく受けることが判る。
なお、前表３および４に記載の細径と太径および肉厚および肉薄という導管径および導管肉厚に関する記載は、導管径および導管肉厚に関して特定基準に基づいて表現したものではなく、前記３種類のチューブの導管径および導管肉厚を相対的に表現したものである。

From the results in the previous table, it can be seen that even when the same amount of bubbles passes, the passage time (mS) required for a predetermined voltage drop rate is greatly affected by the data on the conduit.
In addition, the description regarding the conduit diameter and the conduit thickness of the small diameter, the large diameter, the wall thickness, and the wall thickness described in Tables 3 and 4 above is not expressed based on the specific criteria regarding the conduit diameter and the conduit wall thickness. FIG. 4 is a relative representation of the conduit diameter and the conduit wall thickness of the three types of tubes.

According to the present invention, in order to calculate the bubble amount in consideration of both the bubble amount detection parameter and the correction parameter, the size of the conduit, the shape and size of the sensor for measuring the attenuation of the ultrasonic wave, The detection error of the amount of bubbles due to various factors such as the flow velocity of the liquid flowing through is kept low. Further, the configuration of the present invention does not require a special device and can be easily implemented. Therefore, it is possible to accurately and easily quantify a small amount (small volume) of bubbles under various circumstances.
However, the bubble amount detection system of the present invention is not limited to a single bubble having a volume of about 0.3 to 1.0 μl, for example, even if it is a bubble having a volume larger than those of a minute amount (minute volume). It is possible to accurately calculate the amount of bubbles by incorporating data relating to the flow rate of the liquid through which the liquid containing bubbles passes and / or data relating to the conduit as correction parameters for calculating the amount of bubbles.

  The bubble amount detection system of the present invention using the flow rate (actual flow rate) as a correction parameter can be used in a dialysis machine to easily and accurately measure the bubble volume of the dialysis machine containing a small amount (small volume) of bubbles. did it.

This will be described with reference to FIG.
A hemodialyzer (not shown) that contacts and purifies blood and dialysate through a semipermeable membrane, a blood circulation system (not shown) that circulates blood, and dialysate supply that delivers and drains dialysate A drainage system (not shown), a blood pump provided in the blood circulation system, a motor control circuit for controlling the rotation speed and direction of the blood pump, and a flow rate (actual flow rate) or flow rate of the blood pump in the motor control circuit A control circuit (CPU) that controls the motor control circuit by transmitting information on the rotation speed and rotation direction for setting the ultrasonic wave and ultrasonic waves are applied to the conduit part mounted on the conduit part that measures the amount of bubbles in the dialyzer Ultrasonic wave detecting means including an ultrasonic transducer that oscillates and a receiving-side vibrator that receives ultrasonic waves oscillated by the ultrasonic vibrator, and a bubble that calculates the amount of bubbles based on the detection result of the ultrasonic wave detecting means Has quantity calculation means In both cases, the flow rate setting data of the blood flow set by the rotation speed of the blood pump is transmitted to the bubble amount calculation means as a correction parameter for calculating the bubble amount. A dialysis machine capable of calculating the accurate amount of bubbles by linking.
In the dialysis apparatus of the present embodiment, in addition to the blood volume setting flow rate data described above, the data on the inner diameter and the wall thickness, the inner diameter and the outer diameter, or the outer diameter and the wall thickness can be used as the correction parameter. good.

The conceptual diagram which shows the bubble amount calculation method in the dialysis apparatus which employ | adopted the bubble amount detection system of this invention. The block diagram which shows the outline of the bubble quantity detection system which uses the conversion table of this invention. The schematic diagram which shows the structure outline of the waveform shape measuring circuit 8 in which the AD converter 14 was incorporated. The schematic diagram which shows the relationship between the waveform of the reception level change with time in bubble detection, and the bubble detection determination output 16 calculated from the comparator. The schematic diagram of the comparator for reading the reception level fall time at the time of bubble detection. The conceptual diagram for showing the problem in the conventional bubble detection apparatus. The conceptual diagram which shows the principle which performs a bubble detection with the conventional bubble detection apparatus. It is a figure which shows the contact state of an oscillation side vibrator | oscillator and a receiving side vibrator | oscillator, and a tube. It is the figure explaining that the contact state of an oscillation side vibrator | oscillator, a receiving side vibrator | oscillator, and a tube changes with the data regarding a conduit | pipe.

Explanation of symbols

1. Ultrasonic vibrator 1a. Oscillator 1b. 1. Receiving-side vibrator Bubble 3 Conduit (tube)
4). 4. Reception level waveform 5. Oscillator circuit Amplifier circuit 7. Rectifier circuit8. 9. Waveform shape measuring circuit 10. Bubble amount calculation means Conversion table 12. Alarm generator 13. Bubble amount integrating means 14. A-D converter 15. Comparator 16. Bubble detection determination output 17. Spring 18. Oscillation side vibrator 19. Receiving-side vibrator 20. Tube 21. Tube 22. Tube Vc. Steady voltage Vs. Bubble determination voltage VB. Voltage minimum point T1. Reception level (voltage) drop time Reception level reduction time The width t1 of the flow direction of the ultrasonic transducer. Point t2 where the measured voltage value is equal to or lower than the bubble determination voltage Vs The end point of the measured voltage is less than the bubble determination voltage Vs

Claims (14)

Ultrasonic detecting means equipped with an ultrasonic transducer that is attached to a conduit through which liquid is fed and that oscillates ultrasonic waves in the conduit portion, and a receiving-side transducer that receives ultrasonic waves oscillated by the ultrasonic transducer And a bubble amount calculation means for calculating the amount of bubbles based on the detection result of the ultrasonic detection means, and data relating to the flow rate of the liquid passing through the conduit is calculated in the bubble amount calculation means. A bubble amount detection system, wherein the bubble amount is calculated by taking in as. Ultrasonic detecting means equipped with an ultrasonic transducer that is attached to a conduit through which liquid is fed and that oscillates ultrasonic waves in the conduit portion, and a receiving-side transducer that receives ultrasonic waves oscillated by the ultrasonic transducer And a bubble amount calculating means for calculating a bubble amount based on the detection result of the ultrasonic detecting means, and taking in the data related to the conduit as a correction parameter for calculating the bubble amount into the bubble amount calculating means. A bubble quantity detection system characterized by calculating The bubble amount detection system according to claim 1, wherein the flow rate data is flow rate data in a conduit portion of a medical device. The bubble amount detection system according to claim 2, wherein the data regarding the conduit is data regarding the conduit portion of the medical device. The parameter for calculating the bubble amount in the bubble amount calculation means is the time when the reception level value (voltage change value) received by the receiving-side transducer decreases below a predetermined value (reception level decrease time), the amount of change in the reception level value ( The bubble detection system according to any one of claims 1 to 4, which is a rate of change in voltage change value) or reception level value. The calculation of the amount of bubbles using the correction parameter in the bubble amount calculation means is to calculate the amount of bubbles under various conditions with respect to the set flow rate or the conduit with a predetermined amount of bubbles (actual bubble amount) pre-existing in the liquid to be fed. 6. A table (hereinafter also referred to as a conversion table) indicating a conversion result between the bubble amount calculation value and the actual bubble amount is created, and the conversion table is used to perform the conversion. The bubble detection system according to Crab. The calculation of the amount of bubbles using the correction parameter in the bubble amount calculation means is performed by calculating the amount of bubbles under various conditions with respect to the set flow rate or the conduit in the presence of a predetermined amount of bubbles (actual bubble amount) in the liquid to be fed. A proportional coefficient (hereinafter also referred to as a correction coefficient α) between the calculated value of the bubble amount and the actual bubble amount is derived, and the correction coefficient α is used as shown in the following equation (1). The bubble detection system in any one of Claims 1-6.
Bubble amount = α × bubble amount calculation value (1) The bubble detection system according to claim 6 or 7, wherein the bubble amount calculation means has an information storage part (memory), and the conversion table or the correction coefficient α is stored in the memory. The reception level decrease time of the bubble amount calculation parameter is the time (reception level decrease time) required for the reception voltage decrease time to decrease below a certain voltage (bubble determination value) from the steady voltage value Vc. The bubble detection device according to claim 5, wherein the bubble detection device is an average value of voltage values. The amount of change in the reception level value (voltage change value) or the rate of change in the reception level value (voltage change value) of the bubble amount calculation parameter was calculated based on the difference between the steady voltage value Vc and the voltage that decreases when the bubble is detected. The bubble detection device according to claim 5, wherein the bubble detection device is a device. A medical device equipped with the bubble amount detection system according to claim 1. The medical device according to claim 11, wherein the medical device is a dialysis device, an infusion device, or a heart-lung machine. 13. The flow rate data obtained by a flow rate detection device or a liquid feeding means of a medical device is transmitted to the bubble amount detection system and used as a correction parameter of the bubble amount detection system. Medical equipment. The medical device is a dialysis device, and the air bubble amount detection system can be used for air bubble detection in dialysis operation and / or air bubble amount detection during priming operation. Medical device.

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