JPH05329132A - Breath by breath metabolism measuring apparatus - Google Patents

Abstract

PURPOSE:To provide a breath by breath metabolism measuring apparatus which enables accurate computation of delay time in expired and inspired gases flowing into a gas density analyzer. CONSTITUTION:This apparatus is provided with an expired/inspired gas sampling mask 2 to be mounted about the mouth of a testee 1, a flow meter 5 which is connected to the expired/inspired gas sampling mask 2 to measure the flow rate of the expired and inspired gases, a sampling tube 3 whose one open end is held securely at the center position of laminar flows of the expired and inspired gases in the flowmeter 5 to introduce a part of the expired and inspired gases, a gas density analyzer 7 which is connected to the other open end of the sampling tube 3 to analyze the concentration of O2 and the concentration of CO2 in the expired and inspired gases and an arithmetic device 12 which adjusts and computes the concentrations of O2 and CO2 corresponding to the flow rates of the expired and inspired gases. Thus, the flow rates of the expired and inspired gases of the testee are made to correspond the concentration of O2 and the concentration of CO2 to be analyzed with the gas density analyzer 7 accurately to determine an activity of the body of the testee, thereby enabling the computing of various data useful for the management of health and motion accurately.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a breath-by-breath metabolism measuring apparatus for measuring a respiratory air flow rate, an O ₂ concentration and a CO ₂ concentration in the respiratory air of a subject, and calculating an oxygen consumption amount.

[0002]

2. Description of the Related Art It is physiologically important to measure the respiratory air flow rate of a subject and the O ₂ concentration and CO ₂ concentration in the respiratory air to obtain, for example, the oxygen consumption amount and to grasp the physical activity amount of the subject. Not only is it possible to obtain valuable data on the above, but it is also necessary in terms of health management and exercise management of the subject.

FIG. 3 shows the respiratory air flow rate of a subject and the O in the respiratory air.
Is an explanatory view showing an essential part of the structure of a conventional breath Vibe less metabolism measuring apparatus for measuring ₂ concentration and CO ₂ concentration, the breathing gas sampling mask 2 mounted on the mouth of the subject 1, the flow meter 5 Connected to the flow meter 5 and an amplifier 6
Is connected. One open end of the sampling tube 3 is fixed to a part of the side wall of the flow meter, and the other open end of the sampling tube 3 is connected to the gas concentration analyzer 7.

Here, the flow meter 5 measures the flow rate of respiratory air of the subject. For example, a hot wire type flow meter is used, and the gas concentration analyzer 7 is an O ₂ gas in the respiratory air of the subject.
For measuring the concentration and the CO ₂ concentration, for example, a polarographic type or infrared absorption type gas analyzer is used.

In this conventional breath-by-breath metabolism measuring device, the respiratory air of the subject whose respiratory air sampling mask 2 is attached to the mouth is sent from the respiratory air sampling mask 2 into the flow meter 5, and a heat-wire type flow is performed. The platinum wire (not shown) of the meter 5 is exposed to breathing air, and the flow meter 5 measures the breathing air flow rate of the subject by detecting that the temperature decreases corresponding to the flow rate of the breathing air. The detection signal is output from the flow meter 5 and input to the amplifier 6, and the amplifier 6 outputs the respiratory air flow rate signal f (t) of the subject.

On the other hand, a part of the respiratory air of the subject is supplied to the gas analyzer 7 through the sampling tube 3, and the O ₂ concentration and CO ₂ concentration in the respiratory air of the subject are measured to obtain the gas. Gas concentration signals O ₂ (t) and CO ₂ (t) are output from the analyzer 7.

[0007]

In the breath-by-breath metabolism measuring device described above, it is necessary to measure the O ₂ concentration and the CO ₂ concentration in association with each respiratory air of the subject. For this purpose, the arrival time of the respiratory air of the subject to the gas concentration analyzer 7 is calculated in consideration of the total length of the sampling tube 3, the shape of the respiratory air sampling mask, the diameter d, the volume and the shape of the flow meter 5. However, it is necessary to adjust and calculate the measured value such that the measured value in the gas concentration analyzer 7 is delayed by the arrival time and associated with the respiratory air flow measured by the flow meter 5.

In this case, the delay time in the sampling tube 3 can be accurately calculated, but the delay time in the respiratory air sampling mask 2 and the flow meter 5 portion differs for each breath, and the respiratory air sampling mask 2 and The volume and shape of the flow meter 5 as well as the way of mounting the flow meter 5 are different, and it is difficult to accurately calculate the delay time in this portion. If the accuracy of the calculation of the delay time of this portion is reduced, the respiratory gas flow rate signal f (t) measured by the flow meter 5 and the gas concentration signal O indicating the O ₂ concentration and the CO ₂ concentration measured by the gas analyzer 7 are obtained. _{Since 2} (t) and CO ₂ (t) do not correspond to each other, it becomes impossible to calculate, for example, the oxygen consumption amount with a proper correlation.

The present invention has been made in view of the present situation of the breath-by-breath metabolism measuring apparatus of this kind as described above, and its purpose is to accurately calculate the delay time of respiratory gas flowing into a gas concentration analyzer. Another object of the present invention is to provide a breath-by-breath metabolism measuring device capable of performing.

[0010]

In order to achieve the above object, the present invention provides a respiratory air sampling mask attached to the mouth of a subject, and a respiratory air sampling mask connected to the respiratory air sampling mask. A flow meter for measuring a flow rate, a sampling tube in which one open end is held and fixed at the center position of the respiratory airflow in the flow meter, and a part of the respiratory air is introduced, and the other open end of the sampling tube. A gas concentration analyzer that is connected and analyzes the O ₂ concentration and CO ₂ concentration in the respiratory air, and is connected to the gas concentration analyzer and the flow meter, and is associated with the respiratory air flow of the subject. It is configured to have a calculation means for adjusting and calculating the O ₂ concentration and the CO ₂ concentration.

[0011]

With this structure, the respiratory air of the subject is sent from the respiratory air sampling mask into the sampling tube through one open end of the sampling tube held and fixed at the center position of the respiratory airflow in the flow meter. , Is supplied to the gas concentration analyzer from the other opening end, and the O ₂ concentration and the CO ₂ concentration are measured.

As described above, since one open end of the sampling tube is held and fixed at the center position of the respiratory airflow in the flow meter where the flow velocity is maximized, the delay of the respiratory air reaching the gas concentration analyzer by the calculation means. Time error is reduced.

Therefore, the respiratory air flow rate of the subject measured by the flow meter connected to the respiratory air sampling mask and the O ₂ concentration and the CO ₂ concentration analyzed by the gas concentration analyzer are calculated. Are accurately associated with each other and adjusted and obtained.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. Here, FIG. 1 is an explanatory diagram showing a configuration of the embodiment, and FIG. 2 is an explanatory diagram showing a configuration of a main part of the embodiment.

As shown in FIG. 1, a flow meter 5 is connected to a respiratory air sampling mask 2 attached to the mouth of the subject 1, an amplifier 6 is connected to the flow meter 5, and an amplifier 6 is connected. An AD converter 11 is connected to the output terminal of the. Further, as shown in FIG. 2, one open end 3 of the sampling tube 3 is located at the center position of the laminar flow in the flow meter.
a is fixed, the other open end 3b of the sampling tube 3 is connected to a gas concentration analyzer 7, and a suction pump 8 is connected to the gas concentration analyzer 7.

In this case, the fixed position of the one open end 3a of the sampling tube 3 is attached to a position as close as possible to the respiratory air sampling mask 2, and the distance d in FIG. 2 is made as small as possible. Further, an amplifier 10 is connected to the output terminal of the gas concentration analyzer 7, and an AD converter 11 is connected to the output terminal of the amplifier 10. Then, as described above, the arithmetic unit 12 including a computer is connected to the output terminal of the AD converter 11 to which the amplifier 6 and the amplifier 10 are connected to the input terminal.

Next, the operation of the embodiment having such a configuration will be described.

The respiratory air of the subject flows into the flow meter 5 from the respiratory air sampling mask 2, and the hot wire type flow meter 5
The platinum wire (not shown) is exposed to breathing air, a decrease in temperature is detected corresponding to the flow rate of breathing air, and the flow meter 5 measures the breathing air flow rate of the subject. The detection signal is
It is output from the flow meter 5 and input to the amplifier 6, and the respiratory air flow rate signal f (t) of the subject is output from the amplifier 6 and is AD-converted by the AD converter 11 and then the arithmetic unit 12
Entered in.

On the other hand, a part of the respiratory air of the subject is supplied to the gas analyzer 7 through the sampling tube 3 and is sucked by the suction pump 8 to be sent between the mercury dropping electrode and the counter electrode. And O ₂ concentration and CO in respiratory air of the subject
₂ concentration is measured and the gas concentration signal O _{2 is} output from the gas analyzer 7.
(T) and CO ₂ (t) are output. The gas concentration signal is amplified by the amplifier 10, AD-converted by the AD converter 11, and then input to the arithmetic unit 12.

In the arithmetic unit 12, the arrival time of the respiratory air of the subject to the gas concentration analyzer 7 is calculated in consideration of the total length of the sampling tube 3 and the respiratory air flow rate measured by the flow meter 5 is calculated. On the other hand, the calculation device 12 performs the adjustment calculation so that the analysis values in the gas concentration analyzer 7 delayed by the arrival time are associated with each other.

In this case, the flow velocity of the respiratory gas in the flow meter 5 which is a cylindrical pipe is the smallest on the pipe wall and the largest on the center line, but when the flow is laminar, the flow velocity on the center line is in the flow meter 5. It is known to be twice the average flow velocity.
By the way, in the embodiment, since one open end of the sampling tube 3 is held and fixed on the center line of the respiratory airflow in the flow meter 5, high-velocity respiratory gas is introduced into the sampling tube 3 and the gas concentration analyzer The error of the delay time until reaching 7 is significantly shortened as compared with the conventional one.

Further, in the embodiment, the sampling tube 3
Since one open end of the respiratory gas is on the center line of the laminar air flow in the flow meter 5, the error of the delay time of the respiratory air based on the shape of the respiratory air sampling mask 2, the diameter d of the flow meter 5, the volume, and the shape is Can be reduced, sampling tube 3
It is possible to calculate the oxygen consumption and the like with extremely high accuracy only by calculating the delay time corresponding to the length. For this reason, the respiratory air flow rate of the subject measured by the flow meter 5 connected to the respiratory air sampling mask 2 and the O ₂ concentration and CO ₂ concentration analyzed by the gas concentration analyzer 7 are calculated by an arithmetic unit. It is possible to accurately calculate the data such as the oxygen consumption amount that is useful for health management and exercise management, by accurately ascertaining the physical activity amount of the subject and accurately adjusting and correlating with 12 It will be possible.

[0023]

As described above, in the present invention, one open end of a sampling tube into which a part of respiratory air is introduced is held and fixed at the central position of the respiratory airflow of the subject in the flow meter, A gas concentration analyzer for analyzing the O ₂ concentration and CO ₂ concentration in the respiratory air is connected to the other open end of this sampling tube. For this reason, the arrival delay time of the respiratory air of the subject to the gas concentration analyzer is shortened, and the respiratory air flow of the subject measured by the flow meter 5 and the gas concentration analyzer 7 are analyzed. The O ₂ concentration and the CO ₂ concentration are accurately associated with each other, the amount of physical activity of the subject can be accurately grasped, and data such as oxygen consumption useful for health management and exercise management can be accurately calculated. become.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a configuration of a main part of one embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a configuration of a conventional breath-by-breath metabolism measuring device.

[Explanation of symbols]

 1 Subject 2 Respiratory air sampling mask 3 Sampling tube 5 Flow meter 6 Amplifier 7 Gas concentration analyzer 8 Suction pump 10 Amplifier 11 AD converter 12 Arithmetic device

Claims (1)

[Claims] 1. A respiratory air sampling mask attached to the mouth of a subject, a flow meter connected to the respiratory air sampling mask for measuring the respiratory air flow of the subject, and the respiration in the flow meter. One open end is held and fixed at the center position of the airflow, and a sampling tube into which a part of the breathed air is introduced, and the other open end of this sampling tube are connected, and the O ₂ concentration and CO ₂ concentration in the breathed air And a gas concentration analyzer for analyzing the above, and a calculation means connected to the gas concentration analyzer and the flow meter for adjusting and calculating the O ₂ concentration and the CO ₂ concentration in association with the respiratory air flow of the subject. A breath-by-breath metabolism measuring device characterized by having.