JPS6063037A - Gas introducing apparatus of exhalation gas analyzer - 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] [Aspects of the Invention] This invention relates to a gas introduction device for guiding respiratory gas sampled to a gas analyzer to be measured. [Technical background of the invention and problems thereof] 02 intake and CO2 production with each breath (Bre
(ath by breath) In order to continuously measure the respiratory gas, 02. Measurement of CO2 concentration and respiratory flow rate is required. Figure 1 shows an example of measurement during artificial respiration, in which tracheal tube 2 is inserted into the trachea of patient 1.
A probe 3 for measuring the flow rate and an adapter 4 for introducing exhaled gas are connected to one end of the probe, and beyond that, a Y piece 6, an intake conduit 7, and an exhalation conduit 8 that form a groove between the artificial respirator 5 and the breathing circuit are connected. Connected. The probe 3 of the flowmeter is connected to the wire 9 and the flowmeter 10, and the probe 11 that leads the gas from the gas introduction adapter 4 is connected to the gas analyzer 1.
Connected to 2. The processing equipment engineer 3 calculates the p02 intake amount and the CO2 production amount from the output signals of the flow meter 10 and the gas analyzer 12.

FIG. 2 shows the details of the gas introduction adapter 4. The gas introduction tube 11 has a metal vibrator 15 at its tip, and this metal pipe 15 is used to collect chemicals, secretions, etc. contained in exhaled gas. Or filter 1 for passing water droplets etc.
4 is installed. Further, the introduction tube 11 is fixed to an O-ring 16 and a mounting screw 17 in the radial direction of the cylindrical breathing circuit of the gas introduction adapter 4. As shown in Fig. 1, the gas introduction adapter 4 is attached so as to be in contact with the switching point between inhalation and exhalation as much as possible, so as to reduce the amount of 02 intake and CO2 produced by re-inhaling the exhaled gas during inhalation. Designed to reduce measurement errors. That is, the gas introduction adapter 4 and the Y piece 6
Care has been taken to reduce the amount of death in the surrounding area.

Figure 3 shows the flow rate waveform (
4) and the carbon dioxide concentration waveform (B). The processing device 13 processes both waveforms and calculates the 02 intake amount and CO2 production amount, but the gas concentration waveform remains unchanged until the gas is sampled by the gas introduction adapter 4 and analyzed by the gas analyzer 12. Since the time taken during gas transportation cannot be ignored, it is necessary to take into account the dead time τ and align the phases of the gas analysis concentration waveform and the flow rate waveform. Normally, the fall of the CO2 concentration waveform at the time of switching from expiration to inspiration is steep, so the fall of the CO2 concentration waveform (B) is similar to the rise of the intake of flow rate waveform (4). The time difference τ between the two is measured and corrected.

Normally, the dead time that occurs in gas concentration measurement is corrected as described above, but if the subject to be measured has a significant heartbeat, for example in the case of infants or children, the period from the end of expiration to the start of inspiration (the Since the gas changes due to the heartbeat in the shaded area of the flow rate waveform in FIG.

Therefore, as seen in the two waveforms in Figure 3 (B), C
The falling portion 1) and 31) of the O2 concentration waveform fluctuates violently, and the falling point becomes vague, making it difficult to measure and correct the dead time τ.

[Object of the invention] This invention improves the problems of the prior art described above.
It is an object of the present invention to provide a device that can accurately measure dead time τ even when the flow is disturbed due to heartbeat or the like.

[Summary of the Invention] In this invention, the gas inlet tube is attached at the tip of the breathing circuit in the direction of gas flow and toward the object to be measured.

[Effects of the Invention] According to the gas introduction device according to the present invention, even if breathing gas is disturbed due to heartbeat or the like, the tip of the introduction tube can be attached toward the side to be measured. The gas (exhaled breath) from the side to be measured is not likely to be sampled into the introduction chamber, and the exhaled air concentration value is maintained until the intake starts, and the exhaled air has a steep fall. Since the waveform can be determined as a waveform, it is possible to accurately correct the phase of the flow rate waveform and the gas analysis waveform.

[Embodiments of the invention] An embodiment of the present invention will be described below.

FIG. 4 is a sectional view of a gas introduction device according to an embodiment of the present invention. A hole into which the introduction tube 11 is inserted is provided on the side surface of the gas introduction adapter 4, and the introduction tube 11 is connected thereto. The introduction tube 11 has a metal pipe 15 at its tip, and a filter 14 is attached to the metal pipe 15. The filter 14 is used to prevent clogging of the introduction tube l] due to chemical secretions, water droplets, etc. contained in the breathing gas, and is made of, for example, sintered metal. In order to sample the gas from the side of the object to be measured as much as possible, this filter 14 is installed on the side of the object to be measured (on the left side of the figure) as shown in Fig. 4.
It is directed towards and installed. Therefore, the metal pipe 15 at the tip of the introduction chief is bent toward the upstream side of the flow of exhaled gas, that is, toward the object to be measured. The introduction tube 11 inserted from the side in this manner is fixed to the introduction adapter 4 with an O-ring 16 and a screw fitting 17.

In this embodiment, the filter 14 has an elongated cylindrical shape, but of course this shape is not critical. Further, the filter does not need to be exactly parallel to the direction of gas flow in the flow path as long as the filter tip does not touch the wall surface of the breathing circuit in the gas introduction adapter. For example, as shown in FIG. 5, the introduction tube 11 and the filter 14 may be attached obliquely to the flow path of the gas introduction adapter 4 toward the side to be measured.

[Brief explanation of drawings]

Figure 1 is a block diagram of a system for measuring 02 intake CO2 production, Figure 2 is a diagram showing an example of a conventional introduction device, Figure 3 is a diagram showing an example of respiratory flow rate and ■2 concentration waveform, 4
The figure shows an introduction device according to one embodiment of the invention, and FIG. 5 shows another embodiment of the invention. 11...Introduction tube, 14...Filter, 15.
・Mounting with metal fittings. Agent Patent Attorney Noriyuki Chika (and 1 other person) Figure 1 Figure 3 Figure 4/4 Figure 5

Claims (1)

[Claims] a breathing circuit through which exhaled and inhaled gas flows; a tube connected to this breathing circuit to introduce exhaled gas into an exhaled gas analyzer; and a tube provided at the tip of this tube to pass through the exhaled gas and guide it into the tube. 1. A gas introduction device for an exhaled gas analyzer, characterized in that the tip of the tube is provided toward the upstream side of the flow of exhaled gas.