JPS60108032A - Closing volume measuring method - 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 uses the He-Bolus method for measuring lung function, in which He-Bolus is forcibly inhaled at the beginning of inspiration and the He-Bolus concentration is measured relative to the expiratory volume during exhalation. FIG. 1 shows a conventional device for carrying out this method. At the beginning of expiration, a bag 1 or He is inhaled through a one-way valve 3, and the bag pressure is When the temperature drops, the switching cock 2 is automatically switched and then the atmosphere is sucked in. During exhalation, the He11 degree of exhaled air supplied through the one-way valve 4 is measured by a He sensor 5 such as a hot wire type, an orifice type, or a mass spectrometry type, and the output signal is sent to the Y-axis input end of an X-Y recorder 6 to record the He concentration. Supplied as a signal. In addition, ultrasonic type 7
0-sensor or the differential pressure type flow sensor 7 shown in the figure and an amplifier 8
The output signal of the expiratory volume measuring device followed by the integrator 9 is supplied to its X-axis input terminal as an expiratory volume signal. With such a device, the X=Y recorder 6 records H for changes in expiratory volume.
The e concentration change is plotted and the closing volume is determined from the slope of the He concentration curve. However, in such a device, the He sensor and the flow sensor are provided separately, which not only makes the device large and expensive, but also increases the volume of the flow pipe, resulting in a time delay or start-up). Due to the large tb, it was not possible to achieve high measurement accuracy.

In addition, when using a differential pressure type 70-sensor, there was also the problem of sensitivity change due to contamination.

Therefore, the sensor of the present invention can detect exhaled air and He.
11! ! The object of the present invention is to provide a method for measuring volume that makes it possible to measure volume.

In solving this objective, the present invention focuses on the fact that, as shown in Table 1, although the sound velocity of He is similar to that of other respiratory gas components, it is uniquely significantly higher. be.

Table 1 Gas sound velocity (0°C) Furthermore, we focused on the fact that the He composition ratio in exhaled air increases due to forced inhalation of He, so the sound speed fluctuates widely due to concentration fluctuations. Determine the expiratory flow velocity V and the sound velocity C from the propagation velocity phase difference in the exhalation direction and the opposite direction between the transmitting and receiving elements spaced apart along the tube, and the oscillation frequency difference in the single Alland method, where ■ is the exhalation flow, and C is He The above object was solved by making it correspond to the concentration signal. In other words, the present invention simply calculates V based on the output signal of an ultrasonic pneumotachograph using a velocity difference method such as a time difference method, a single-Around (frequency difference) method, or a phase difference method, which are well known per se. It is characterized in that C is also calculated and its fluctuations are treated as He concentration fluctuations.

Hereinafter, an example of an apparatus for carrying out the method according to the present invention will be explained based on the drawings.

In Figure 2, the intake air supply part is the same as in Figure 1,
A pair of ring-shaped ultrasonic transducers 11 and 11' (hereinafter simply referred to as elements) that can transmit and receive ultrasonic waves within the tube are attached along the respiratory air flow path 10. When these elements 11 and 11' are made to alternately send a pulse to one element 11, the other element 11' receives it, and conversely, when element '11 is made to receive it, element xf a transmitting/receiving circuit 12 that transmits data to
0 is attached. This calculation unit 20 includes elements 11 and 11.
a propagation time measurement section 21 that measures the exhalation direction propagation time T1 and backward propagation time T2 of the ultrasonic waves between the two on the basis of the transmitted and received signals of the transmitting and receiving circuit 12; and a reciprocal section 22.23 that calculates the reciprocal values of Tl and TiI. , an addition section 24 and a subtraction section 25 for the respective reciprocal values.

As a result, the integral signals of the PA signal and the NO signal, which correspond to the calculated values when the distance between the elements 11 and 11' is L, can be outputted to, for example, the X-Y recorder 6 in FIG. 1 or the cathode ray tube waveform display device. are supplied as Y-axis and X-axis inputs to output devices such as the following. During such measurements, H
If, for example, about 300 cc of e is inhaled, the He composition ratio of the exhaled breath during exhalation is about 5 to 10 cm, and the speed of sound is about 3 times that of other composition gases.
A CT signal, ie, a sound velocity signal, can be obtained with sufficient measurement accuracy as a He concentration signal.

In addition, in FIG. 2, the elements 11, 11' can also be arranged in the flow path tube 27 exclusively for exhalation, as long as the wasted volume including the dead space volume can be tolerated.

The elements 11.11' may be arranged transversely in the airflow tube as shown in FIG. The transmitting/receiving circuit 12 includes an element 1
1111' at the same time, the other party's element 11 or 1
1' transmission signals can also be mutually received. Each time the other element 1f or 1 receives a transmission pulse from one element 11 or 11' in FIG. When using the single Alland method of calculating the speed from the transmission frequency, V and C are calculated as follows. The transmission frequency of the element 11 counted by the counter in the calculation section is f
Rin, the transmission frequency of one element is fz, and the distance between pixel elements is L.
Then, 1.1-stop α fz = dan2X L ゝ L .

Therefore, by adding the difference and sum of the count values f1 and fz to the adder/subtractor circuit, we get f・−f・−−1, f・+f・=2V L' L. V and C are calculated from the difference and sum of the transmission frequency ft from the side and the transmission frequency f2 from the exhalation downstream side.

A phase difference method is used in which the transmitted signals from both elements 11.1 in Fig. 2 are received by the opposing elements 11' and 11, and the speed is calculated from the phase difference of the received signal with respect to each superstition signal. If you do, it will look like this: The phase shift of the received signal of element 11' corresponding to the transmission frequency fO1 propagation distance is φ1, and the phase shift of the received signal of element 11 is φ2.
In the arithmetic section, first calculate. Here, even at the maximum expiratory flow, n1 = n
If f・ is selected so that u
) Tonashi, therefore, is calculated from this formula. Furthermore, from equations (1) and (2), φ8+φ凰= (Δφ凰+2n7)+(Δφ凰+2 nu z )
1 = (σ: ~= Jukoku, V-) 2πLf・91+1 Therefore, from this formula, C becomes as follows.

From this equation and equation (3), ■ becomes as follows.

In other words, the phase difference △ that occurs on the downstream side of exhalation corresponding to the propagation velocity difference
■ and C are calculated from the difference and sum of φ1 and the phase difference Δφ2 occurring on the upstream side of expiration.

As described above, according to the present invention, not only the conventional exhalation flow but also the sound velocity is calculated based on the difference and sum of the ultrasonic propagation velocity in the exhalation flow direction and the opposite direction for exhalation passing between the ultrasonic vibrating elements. By using it as a signal, it becomes possible to measure expiratory flow and He concentration with a single ultrasonic sensor during closing volume measurement.

Therefore, the device can be made cheaper and smaller, and the response characteristics at the beginning of exhalation can also be improved.

[Brief explanation of drawings]

FIG. 1 shows the configuration of a conventional closing volume measuring device, FIG. 2 shows a device for implementing the closing volume measuring method according to the present invention, and FIG. 3 shows another example of the device according to the present invention. 11.1f...Ultrasonic vibration element 20...Calculating unit φ1) Agent Masaharu Fukutome Figure 1 Figure 2 Figure 3 Figure 11' 11111 Procedural Amendment July 21, 1982 Manabu Shiga, Director General of the Japan Patent Office1, Indication of Weakness 11r (Japanese Patent Application No. 216812, 2013,
Title of the invention Closing volume measurement method 3, person making the correction/relationship with case h Applicant address 1-31-4 Nishiochiai, Shinjuku-ku, Tokyo Name "1"
Honkoden Kogyo Co., Ltd. 4, Agent 〒151 6, Detailed explanation of the invention of the month subject to amendment column 7, Supplementary contents of the description, page 4, line 6, page 4, line 1o, page 6, 2o I will correct the line "Around" to "Around".

Claims (1)

[Claims] In the method of forcibly inhaling He at the beginning of inspiration, measuring the expiratory volume and He concentration in expiration during exhalation, and measuring the closing volume from the relative relationship between constant values on both sides, the ultrasonic transmitting and receiving elements are spaced apart along the respiratory air flow path. The expiratory velocity V and the sound velocity C are calculated from the ultrasonic propagation velocity in the exhalation direction and the opposite direction between these elements, and the expiration velocity V is made to correspond to the exhalation flow and the sound velocity C is made to correspond to the He concentration. Closing volume measurement method.