JPS5846963A - Ultrasonic detecting apparatus for hemodyalysis - 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 The present invention relates to an ultrasonic detection device that is used in an artificial kidney device system for artificial dialysis of blood and detects blood levels and air bubbles contained in coughed blood using ultrasonic waves. 1. In artificial dialysis, blood is circulated extracorporeally, and blood is extracted from an artery, purified by an artificial kidney system, and then returned to a vein. in this case,
If air bubbles are mixed into the blood being returned to the veins, these air bubbles may be carried to the brain and cause serious problems such as unconsciousness or convulsions, so the blood being returned to the veins must be constantly monitored. Measures are taken to immediately stop the flow of blood when air bubbles enter the tube. As a device for detecting such air bubbles in blood, the following ultrasonic detection device has conventionally been used. That is, a first ultrasonic transducer is provided on one side of the pipe through which blood returns to the vein flows, and the ultrasonic transducer is continuously oscillated at a resonance point to emit ultrasonic waves. The ultrasonic transducer also detects the ultrasonic waves propagated in the blood, and the detection signal uses the fact that the signal level is different when blood is present in the pipe and when air bubbles are present. Therefore, an ultrasonic detection device was used to detect the presence or absence of air bubbles in the blood.

However, in the conventional example of the ultrasonic detection device, since the first ultrasonic transducer is configured to continuously oscillate at a resonance point, the detection signal from the 20th ultrasonic transducer is amplified and rectified. Good signal.

The waveform changes only slowly, and small air bubbles contained in the blood in the pipe cannot be detected.The ultrasonic waves emitted from the first ultrasonic transducer are transmitted along the wall surface of the pipe. There are two types of ultrasonic waves: those that propagate through the blood in the pipe and those that propagate through the blood in the pipe. Another drawback was that it was difficult to set the bubble detection level.Furthermore, since the first ultrasonic transducer is configured to vibrate at its resonance point, the resonance point of the Isata transducer is subject to manufacturing variations. There is also a drawback that it is difficult to maintain the output level from the vibrator at a constant value due to deviations due to temperature changes.The present invention has been developed in view of these drawbacks. The purpose is to remove all the above defects and reduce the size to 1mm1! It is an object of the present invention to provide an ultrasonic detection device for hemodialysis which can detect even small air bubbles and can also be used for blood level detection.

Hereinafter, the present invention will be explained in detail using figures. 1st
The figure is an explanatory diagram of the configuration of an embodiment of the present invention. In the figure, 1 is a pipe used for artificial dialysis and blood, etc. is flowed inside, 2 is blood flowing through the pipe, and 5 is contained in blood. Air bubbles flowing through pipe 1, 4a.

4b is a Jill and a second ultrasonic vibrator mounted on a predetermined portion of the pipe 10 so as to sandwich the pipe;
is an amplifier 6 that amplifies the output of the second ultrasonic transducer 4b;
is a rectifier that rectifies the output of the amplifier 5, and 7 is the rectifier 6.
8 is an oscillator that outputs, for example, a rectangular wave voltage, and 9 receives the output of the oscillator 8 and outputs a signal that exceeds a preset level for a preset time. (hereinafter referred to as "delay time t") and outputs a delay circuit 31;
11 is a latch circuit that receives the output of the delay circuit 9 and uses it as a control signal, and also receives the output of the comparator 7 and doubles the output according to the control signal; 11 receives the output of the 4E signal circuit 8 and amplifies it; At the same time, it is a driver that excites the first ultrasonic transducer 4a to emit ultrasonic waves according to the output.

The operation of the embodiment of the present invention having the above configuration will be described below. FIG. 2 is a time chart illustrating the operation of the embodiment of the present invention. In the output waveforms, C is the output waveform of the rectifier 6, D is the output waveform of the comparator 7, and C is the output waveform of the latch circuit 10. 1, when the oscillator 8 outputs, for example, a rectangular wave voltage as shown in FIG. 2 (chrysanthemum),
The output is amplified by the driver 11 and then reaches the first ultrasonic transducer 4aK, which excites the transducer 4a to oscillate ultrasonic waves. The ultrasonic waves propagate through the blood 2 or air bubbles 3 in the pipe 1, reach the second ultrasonic transducer, and are detected by the transducer 4b. The detected signal of the vibrator 4b is amplified by the amplifier 5, for example, as shown in FIG. The comparator 7 is set in advance to output only signals exceeding a predetermined level), and when the output signal of the rectifier 6 is input to the converter converter 7, the output of the comparator 7' For example, it becomes as shown in Figure 2 (b). On the other hand, the output of the oscillator 8 is also supplied to the delay circuit 9;
In this case, the delay time t is set to be equal to the time for the ultrasonic wave to propagate through the blood 2 in the pipe 1, and the output of the delay circuit 9 is used as a control signal. The output will be as shown in FIG. 2, for example. by the way,#! In FIG. 2, for example, if air bubbles 5 mix into the blood 2 in the pipe 1 in FIG. Rectifier 6. The output waveforms of the booster 7 and the sub-circuit 10 change as shown in the figure,
In particular, the output of the latch circuit 1a becomes zero. Therefore, it is necessary to monitor the output waveform of the latch circuit 1G.
It is determined whether air bubbles 5 have mixed into the blood 2 inside.

. It should be noted that an appropriate value is selected for the oscillator 80 period depending on the speed of the blood 2 flowing in the pipe 1 and the size of the bubble 3, which is the object contained in the blood 2. Further, the predetermined level setting in the comparator 7 is selected to be an appropriate value depending on the noise superimposed on the rectifier 60''al force signal. The ultrasonic waves transmitted from the first ultrasonic transducer and propagated through the blood and air bubbles in the pipe are received by the second ultrasonic transducer, and the output signal of the second ultrasonic transducer is transmitted to the ultrasonic wave. It has the advantage of not being affected by the predetermined resonant frequency propagating in blood, fluctuations due to temperature, or ultrasonic waves propagating on the wall surface of the pipe. Since the vibrator is not configured to continuously oscillate at the resonance point, all of the drawbacks of the conventional example, such as the possibility that small air bubbles contained in the blood in the pipe will not be detected, are eliminated. FIG. 3 is an explanatory view showing the main parts of an actual measurement example using the embodiment of the present invention. In the figure, 12 is the venous blood chamber, and 13 is the blood stored in the venous blood chamber 12. Blood, 14 is the body to be treated, such as a patient's arm, 1
5 is a first pipe that guides the blood 13 in the venous blood chamber 12 to the subject to be treated 14; 16 is an aero tube that cools a predetermined portion of the first pipe 15 at a desired time; and 17 is a dialysis machine, etc. 18a and 19a are first ultrasonic transducers, and 18b and 19b are second ultrasonic transducers. In the measurement example having the above configuration, blood led from a dialyzer or the like into the venous blood chamber 12 via the second pipe 17 is separated into gas and liquid in the venous blood chamber 12, and It is returned to the vein of the subject 14 via the pipe 15. Further, the first and second ultrasonic transducers 19a and 19b operate in the same manner as the first and second ultrasonic transducers 4a and 4b in the embodiment of the present invention, and the Detects air bubbles in blood. Furthermore, first and second ultrasonic transducers 1
8a and 18b are also the first and second in the present invention.
The ultrasonic transducers 4a and 4b operate in the same way as the ultrasonic transducers 4a and 4b, and by detecting the upper space of the blood 13, which corresponds to extremely large bubbles, the blood level in the venous blood chamber 12 (or the blood level reaches a predetermined value). Detects when the vehicle reaches a so-called danger position (9). Therefore, the first and second ultrasonic transducers 18m and 18b detected that the blood level had reached a dangerous position), and the first and second ultrasonic transducers 19m and 19b detected that the blood level had reached the dangerous level. When air bubbles contained in the blood flowing inside the pipe 15 are detected, air haze,
The pipe 16 is driven to stop the blood flow in the first pipe 15.

Furthermore, FIG. 4 is an explanatory view showing the main parts of another measurement example using the embodiment of the present invention, in which 20 is a dialyzer, 21 is a dialyzer 20, and a first chamber 22 and a second chamber. A dialysis membrane is provided in the chamber 23 and ultrafilters water contained in the blood, etc. in the first chamber 22 into the second chamber 23, and 24 is blood pumped by a circulation pump or the like. A first pipe 25 guides the blood into the first chamber 22, a second pipe 25 guides the blood in the first chamber 22 to a subject to be treated, and a second pipe 26 attached to a predetermined portion of the second pipe 250. An autocleaner that adjusts the pressure of blood flowing through the part, 27 is an Ultra Fil
tration Ratio measuring tube (hereinafter simply r U
28 is a dialysis membrane 2 in the second chamber 23.
A fifth pipe, 29a, 29b, which guides the moisture that has arrived via 1 to the UFR metering tube, is the first and second ultrasonic vibrator, 30m, provided near the outlet of the UFR metering tube.
Reference numeral 30b denotes first and second ultrasonic vibrators provided near the inlet of the UFR metering tube.

In another measurement example having the above configuration, the first pipe 2
The blood that has been fed through the dialysis membrane 4 and reaches the first chamber 22 is ultrafiltered by the dialysis membrane 21 to remove water contained in the blood, and then reaches the second chamber 23 . Water is removed by mosquito filtration, and the blood passes through the second pipe 25 and is led out from the first chamber 22 at a predetermined flow rate.The blood also reaches the second chamber 23 by the ultrafiltration. The moisture enters the VFR metering tube 27 via the fifth pipe 28, and the moisture enters the VFR metering tube 27.
When the number is full 9, it is extracted from the output port. Therefore, the first
and M2 ultrasonic transducer 29a, 29b or 3
0a and 30b operate in the same manner as the first and second ultrasonic transducers 4a and 4b in the embodiment of the present invention, and
The level of the moisture reaching the vicinity of the inlet and outlet of the FR metering f27 is detected. In addition, the above VFR (Ultr
a Filtration Ratio) is the first chamber 2
The product of the pressure of the blood in 2 and the time required for ultrafiltration of the above water is the 9 value obtained by dividing the amount of water that is ultrafiltered by 9, which is also an indicator of the performance of the dialyzer 20. , the above-mentioned measurement using the UFR measuring tube 27 is performed because the value shows a change over time. .

According to the measurement examples described in detail with reference to FIGS. 5 and 4, the advantages of the embodiments of the present invention are exhibited, and the measurements are more efficient (compared to the case of using the conventional examples). 0

[Brief explanation of drawings]

FIG. 1 is a configuration explanatory diagram of the embodiment of the present invention, FIG. 2 is a time chart explaining the operation of the embodiment of the present invention, and FIG. 3 is a main part of a measurement example using the embodiment of the present invention. It is an explanatory diagram. 1.15.17.24.25.28...pipe, 2,
13...Blood, 3...Bubble% 4a, 4b, 18
a, 18b, 19a, 19b, 29a, 29b, 30a
, 30b... Ultrasonic transducer, 5... Amplifier, 6...
- Rectifier, 7... Comparator 18... Oscillator, 9
... Delay circuit, 10... Latch circuit, 11... Dryno<-112... Venous side blood chain (,20.
...Dylyzer, 21...Dialysis membrane, 27:...UFR measuring tube 0o /[! 1 1θ O 3 Figure O 4 Closed

Claims (2)

[Claims] (1) An oscillator that outputs a predetermined voltage in an ultrasonic detection device that is used in an artificial kidney device system that performs artificial dialysis of blood and uses ultrasound to detect the level of blood and air bubbles contained in the blood. , a driver that amplifies the output of the transducer, a second ultrasonic transducer that transmits the signal, an amplifier that amplifies the output of the ultrasonic transducer of the broom 2, and a rectifier that rectifies the output of the amplifier. a comparator that receives the output of the rectifier and outputs only a signal exceeding a predetermined level among the outputs; a delay circuit that receives the output of the oscillator and delays the output by a predetermined time and outputs the output; An ultrasonic detection device for hemodialysis, comprising a latch circuit that uses the output of the delay circuit as a control signal to control the output of the comparator. (2) A predetermined portion of the tube through which blood used for artificial dialysis flows is sandwiched between the first and second ultrasonic transducers, and a delay time in the delay circuit is set such that the ultrasonic waves The ultrasonic detection device for hemodialysis according to claim 1, wherein the ultrasonic detection device for hemodialysis is configured to detect the level of the blood or air bubbles contained in the coughed blood by setting the time during which the blood propagates through the blood.