JPH08338793A - Exhalation sampling tube - Google Patents

Abstract

PURPOSE: To obtain an exhalation sampling tube in which the exhalation sampled from a testee can be introduced surely to a bag while removing the initial exhalation for the purpose of carbon isotope test. CONSTITUTION: The branched tube from a T-shaped housing 11 is provided with a piston 12 being pushed up by the initial exhalation having a hole 15 for discharging the initial exhalation to the outside, a spring 13 for returning the piston 12 upon stopping introduction of exhalation, a cavity for storing the initial exhalation, and a vent 14 for discharging the initial exhalation gradually to the outside. Furthermore, the linear tube of T-shaped housing 11 is provided with a channel 22 for feeding exhalation other than the initially exhalation, and a differential pressure check valve 16 acting with a pressure higher than the force of a reset spring 13 of piston 12 to prevent reverse flow of exhalation passed through the channel 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhalation sampling tube for exhaling a subject in a carbon isotope exhalation test.

[0002]

Breath test is using BACKGROUND ART Carbon isotope, the subject of breath after the administration of reagents standardized ₁₃ C is a stable isotope of carbon fixed amount collected, ₁₃ CO contained in this
The ratio of _2/12 CO _2, i.e. by analyzing the time course of isotopic ratios, a means of diagnosing functions and disease states of the internal organs.

[0003] Since this test method is safe and painless, it is used in radioisotopes 40, 475-48.
4 (191) “Progress of carbon isotope breath test in Japan”
As shown in, the application is widely studied.

At the time of exhalation, the exhalation from the subject is introduced into the exhalation bag, and the carbon isotope ratio in the exhalation bag is analyzed to make a diagnosis. Here, in order to diagnose the function of the internal organs, it is necessary to analyze the change in the isotope ratio with an accuracy of about 1/1000, and for this reason, it is necessary to minimize atmospheric contamination in the collected exhaled breath. I won't.

FIG. 3 is a sectional view of a conventional exhalation sampling tube, 1 is a housing, 2 is a silicone rubber stopper, 3 is a mouthpiece connecting tube,
4 is a mouthpiece, 5 is silica gel, 6 is an exhalation bag,
Reference numerals 7 and 8 denote filters that prevent dust and silica gel powder from entering the exhalation bag 6. Subject is a mouthpiece 4
Breathe more. The exhaled breath is dehumidified by passing through the silica gel 5 and introduced into the exhalation bag 6.

[0006]

However, since the conventional exhalation sampling tube has the above-described structure, the exhaled air that has come out of the oral cavity at the initial stage of exhalation of exhaled air after inhalation into the atmosphere,
That is, both the initial exhalation that did not reach the lung and the exhalation in which the exchange of O ₂ and CO ₂ was sufficiently performed in the lung were introduced into the exhalation bag.

Generally, the concentration of CO ₂ contained in the atmosphere is about 0.03%, but this atmosphere causes oxygen in the lungs due to respiratory motion.
₂ and CO ₂ are exchanged and discharged. This breathing exercise raises the CO ₂ concentration of the exhaled breath to 3 to 5%. However, in the initial exhalation, most of the atmosphere was accumulated in the mouth and trachea, and the CO ₂ concentration was low. The amount of this initial exhalation varies depending on the individual, but is about 100 ml for an adult.

Therefore, the introduction of the initial exhalation into the exhalation bag diminishes the exhalation that should originally enter the exhalation bag, and the amount of CO ₂ required for analysis cannot be obtained. To what extent the CO ₂ concentration changes, using a conventional exhalation sampling tube,
The exhaled breath having a CO ₂ concentration of 3 to 5% was sampled in a 2 liter breath bag, and as a result of an experiment, it was found that CO ₂ concentration was 1 to 4% though it varied greatly depending on sex and age.
And the concentration decreased.

Moreover, when CO ₂ contained in the atmosphere and having different isotope ratios is mixed in the exhaled breath, the CO ₂ isotope ratio in the exhaled breath to be originally analyzed is different.

[0010]

In order to solve the above problems, the present invention provides a piston having a hole for pushing up the initial expiratory air in the T-shaped housing and discharging the expiratory air to the outside. A spring for returning the piston when exhalation is stopped, a cavity for accumulating initial exhalation, a vent for gradually discharging the initial exhalation to the outside, a flow path for exhalation other than initial exhalation, and the flow It is provided with a differential pressure check valve that prevents backflow of exhaled air that has passed through the passage and that operates with a larger pressure than a spring for returning the piston.

In the carbon isotope exhalation test, the purpose is to temporarily store only the initial exhaled breath in the exhaled breath collected from the subject in the exhaled breath collection tube, and the pressure of the exhaled breath that later enters the exhaled breath collection tube causes the piston to move. By gradually discharging the initial exhalation from the hole to the outside, the introduction of the initial exhalation into the exhalation bag is not made aware of the subject and is reliably prevented.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a cross-sectional view of this embodiment.
Is a housing, 12 is a piston, 13 is a spring, 14 and 15 are vents, 16 is a differential pressure check valve, 17 is a mouthpiece, 18
Is silica gel, 19 is an exhalation bag, 20 and 21 are filters, and 22 is a flow path. 2 shows a perspective view of each component in the embodiment shown in FIG.

In FIGS. 1 and 2, the end surface X'of the housing 10 is shown.
Is adapted to be fitted into the end surface Y of the casing 11, and the end surface Y ′ is a form that can be attached to the exhalation bag 19, and the filter 20 and the silica gel 18 can be incorporated inside the exhalation bag 19 side.

Here, the silica gel 18 dehumidifies the expiratory air passing therethrough, and the filter 20 functions to prevent the powder of the silica gel 18 from flowing out to the expiratory bag 19. As the material of the filter 20, a mesh or a non-woven fabric is used because it is required to have good breathability.

The casing 11 is formed by connecting two pipes in a T-shape, and the end surface Z of the branch has a closed structure. Further, the end face X has the mouthpiece 17 attached thereto, and the end face Y has the housing 10
Can be fitted to the end face X'of
A vent 14 is provided for discharging unnecessary gas inside the housing 11. Further, at the branch of the housing 11, the piston 1
2, the spring 13, and the differential pressure check valve 16 and the filter 21 are attached to the linear portion.

The piston 12 is pushed up in the direction of the end surface Z by the pressure of the exhaled air coming in from the end surface X of the housing 11, and stores the initial expiratory air inside the branch of the housing 11 to about 100 m.
There are 1 cavities.

Further, the piston 12 is provided with a vent hole 15 for gradually discharging the initial expiratory air to the outside by the pressure of the expiratory air that comes in after forming the cavity.
The vent hole 15 may be displaced from the vent hole 14 on the end surface Z. The spring 13 is a coil spring that returns the piston 12 to the initial position when the introduction of exhalation from the end surface X of the housing 11 is stopped.

The differential pressure check valve 16 is a check valve that opens the valve when the pressure applied by the expiratory air on the piston 12 compresses the spring 13, and when the pressure rises, closes the valve when the pressure is low. Prevent the distribution of. Such valves are widely used for fluid control and the like.

The filter 21 prevents the powder of the silica gel 18 from flowing back to the differential pressure check valve 16. The mouthpiece 17 is a paper cylinder and is widely used for measuring lung function. The exhalation bag 19 is formed by superimposing two films having a low CO ₂ permeability of the shape shown in FIG. 2 on FIG. 2 and excluding the exhalation-introduced portion, and the outer periphery is fused or adhered. It is used.

The operation of the exhalation sampling tube will be described below. First, the silica gel 18 is put in the housing 10, and the housing 1 is put in the housing 11.
0 is inserted, and the exhalation bag 19 and the casing 1 are attached to the casing 10.
Attach the mouthpiece 17 to 1.

Next, exhalation is blown from the mouthpiece 17 attached to the housing 11. The pressure of the exhaled air pushes up the piston 12 and simultaneously compresses the spring 13. Initial exhalation enters the cavity created by the piston 12 being pushed up. At this time, the air around the spring 13 is exhausted to the outside through the vent hole 14, so that the pressure that causes a load when the air blows in the exhaled air is not generated.

When the piston 12 rises to the top, the pressure in the casing rises due to the strong exhalation that is applied, and the small amount of outflow from the small vent holes 14 and 15 to the outside causes the differential pressure check valve 16 to open, which is the initial stage. Exhalation other than exhalation is exhalation bag 1
Introduced in 9. At the same time, the initial exhalation accumulated in the cavity passes through the 15 vent holes and is gradually discharged from the 14 vent holes to the outside. When the exhalation is finished, the differential pressure valve 16
Is closed, the backflow of the exhalation from the exhalation bag 19 is blocked, and the piston 12 is returned to the initial state by the force of the spring 13. With such an action, as a result, the exhaled air excluding the initial exhaled air can be introduced into the 19 exhalation bag 11.

[0023]

As described above, the exhaled air from which the initial exhaled air has been removed can be introduced into the exhalation bag, and the amount of CO ₂ required for analysis can be stably secured. Further, since there is no atmospheric mixture, the isotope ratio of exhaled CO ₂ to be originally analyzed can be obtained.

Using this exhalation sampling tube, CO ₂ concentration of 3-5%
As a result of collecting the exhaled air in a 2 liter exhalation bag and conducting an experiment to see how much it changed, a CO ₂ concentration of 3 to 5% was obtained, and the effect of removing the initial exhalation was confirmed.

[Brief description of drawings]

FIG. 1 shows a cross-sectional view of an exhalation sampling tube according to an embodiment.

FIG. 2 is a perspective view of each part of the exhalation sampling tube shown in FIG.

FIG. 3 shows a cross-sectional view of a conventional exhalation sampling tube.

[Explanation of symbols]

 1 Case 2 Silicon Rubber Plug 3 Mouthpiece Connection Tube 4 Mouthpiece 5 Silica Gel 6 Expiration Bag 7 Filter 8 Filter 10 T-Shaped Case 11 Case 12 Piston 13 Spring 14 Vent 15 Vent 16 Differential Pressure Check Valve 17 Mouthpiece 18 Silica gel 19 Breath bag 20 Filter 21 Filter 22 Flow path

Claims (1)

[Claims] 1. An exhalation sampling tube having one end of a T-shaped casing 11 provided with a branch connected to a mouthpiece 17 and the other end connected to an exhalation bag 19 via a moisture absorption section, A piston 12 that is pushed up by the initial exhalation and has a hole 15 for discharging the initial exhalation to the outside; and a spring 13 for returning the piston 12 when the exhalation introduction is stopped.
A cavity for accumulating the initial exhaled air, and a vent 14 for gradually discharging the initial exhaled air to the outside, and a flow of exhaled air other than the initial exhaled air flowing in the straight portion of the T-shaped casing. An exhalation sampling tube provided with a passage (22) and a differential pressure check valve (16) for preventing backflow of exhaled air that has passed through the passage (22) and operating with a pressure larger than that of a spring (13) for returning the piston (12).