JP2916883B2 - Breath collection tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a breath collection tube for collecting a subject's breath in a carbon isotope breath test.

[0002]

2. Description of the Related Art In a breath test using a carbon isotope, a certain amount of breath of a subject is collected after administration of a reagent in which ₁₃ C, which is a stable isotope of carbon, is standardized, and ₁₃ CO contained therein is collected.
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 FIG.

During exhalation, exhalation from a subject is introduced into an exhalation bag, and a diagnosis is made by analyzing the carbon isotope ratio in the exhalation bag. Here, in order to diagnose the function of the internal organs, it is necessary to analyze the change of the isotope ratio with an accuracy of about 1/1000, and therefore, it is necessary to minimize the entry of air into the collected exhaled breath. No.

FIG. 3 is a cross-sectional view of a conventional exhalation collection tube, wherein 1 is a housing, 2 is a silicone rubber stopper, 3 is a mouthpiece connection tube,
4 is a mouthpiece, 5 is silica gel, 6 is a breath bag,
Reference numerals 7 and 8 denote filters for preventing dirt and silica gel powder from entering the expiration bag 6. The subject was a mouthpiece 4
Inhale more breath. The blown breath is dehumidified by passing through the silica gel 5 and is introduced into the breath bag 6.

[0006]

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

Generally, the concentration of CO ₂ contained in the atmosphere is about 0.03%.
₂ and CO ₂ are exchanged and discharged. With this respiratory movement, the CO ₂ concentration of the exhaled air increases to 3 to 5%. However, the initial expiration is mainly composed of the air accumulated in the mouth and trachea, and the CO ₂ concentration is low. The volume of this initial expiration varies among individuals, but is about 100 ml for adults.

[0008] Therefore, when the initial exhalation is introduced into the exhalation bag, the exhalation which should be originally contained in the exhalation bag becomes thin, and the amount of CO ₂ necessary for analysis cannot be obtained. To determine how much CO ₂ concentration changes, use a conventional breath collection tube,
As a result of collecting the exhaled air with a CO ₂ concentration of 3 to 5% into a 2 liter exhalation bag and examining how much it changes, the CO ₂ concentration varies depending on gender and age, but the CO ₂ concentration is 1 to 4%
And the concentration decreased.

[0009] In addition, CO ₂ having a different isotope ratio contained in the atmosphere is mixed into the breath, resulting in a different isotope ratio of CO _{2 in} the breath to be originally analyzed.

[0010]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a T-shaped housing having a piston which is pushed up by initial exhalation and has a hole for discharging the initial exhalation to the outside, A spring for returning the piston when the exhalation is stopped, a cavity for storing the initial exhalation, a vent for gradually discharging the initial exhalation to the outside, a flow path for exhalation other than the initial exhalation, It has a differential pressure check valve that prevents backflow of exhaled air passing through the passage and operates at a pressure larger than a spring for returning the piston.

[0011] The purpose is to temporarily store only the initial exhaled gas in the exhaled breathing tube in the exhaled breathing tube in the carbon isotope breath test, and use the pressure of the piston by the exhaled breath pressure that enters the exhaled breathing tube later. By gradually discharging the initial expiration from the hole to the outside, it is possible to surely prevent the test subject from introducing the initial expiration into the expiration bag.

[0012]

FIG. 1 is a sectional view of the present 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 a breath bag, 20 and 21 are filters, and 22 is a flow path. FIG. 2 is a perspective view of each component in the embodiment shown in FIG.

1 and 2, an end face X 'of the housing 10 is shown.
The end face Y 'is adapted to fit into the end face Y of the housing 11, and the end face Y' can be attached to the expiration bag 19. The filter 20 and the silica gel 18 can be built in the expiration bag 19 side.

Here, the silica gel 18 performs dehumidification of the expired breath, and the filter 20 functions to prevent the powder of the silica gel 18 from flowing out to the breath bag 19. Since the material of the filter 20 needs good breathability, a mesh or nonwoven fabric is used.

The housing 11 has two tubes connected in a T-shape, and has a structure in which the end face Z of the branch is closed. 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 ventilation port 14 for discharging unnecessary gas inside the housing 11 is provided. Further, the branch of the housing 11 includes a piston 1
2, a differential pressure check valve 16 and a filter 21 are attached to the spring 13 and the straight portion.

The piston 12 is pushed up in the direction of the end face Z by the pressure of the exhaled air coming from the end face X of the casing 11, and stores the initial exhaled breath inside the branch of the casing 11 for about 100 m.
l cavities are created.

Further, the piston 12 is provided with a ventilation port 15 for gradually discharging the initial exhalation to the outside by the pressure of the exhalation entering after the cavity is formed.
The position of the vent 15 may be shifted from the position of the vent 14 on the end face 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 face X of the housing 11 is stopped.

The differential pressure check valve 16 is a check valve which opens the valve when the pressure rises, and the valve closes 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 laminating two films having a low CO ₂ transmittance having the shape shown in FIG. 2 at 19 and fusing or bonding the outer periphery except for the exhalation introduction portion. It is used.

The operation of the breath collection 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 into the case 10, the breath bag 19 and the case 1
The mouthpiece 17 is attached to 1.

Next, exhalation is blown from the mouthpiece 17 attached to the housing 11. The pressure due to exhalation pushes up the piston 12 and at the same time compresses the spring 13. The initial exhalation enters a cavity generated by the piston 12 being pushed up. At this time, since the air around the spring 13 is discharged to the outside from the ventilation port 14, no pressure is generated so that the air becomes a load when the air is blown.

When the piston 12 rises to the uppermost position, the pressure inside the casing rises due to the strong expiration and the amount of outflow from the small vents 14 and 15 to the outside is small, so that the differential pressure check valve 16 opens, Exhalation other than exhalation, exhalation bag 1
9 is introduced. At the same time, the initial expiration stored in the cavity passes through the 15 vents and is gradually discharged from the 14 vents to the outside. When the expiration is finished, the differential pressure valve 16
Is closed, and the backflow of the exhalation from the exhalation bag 19 is prevented, and the piston 12 returns to the initial state by the force of the spring 13. Since such an action is performed, the exhaled breath excluding the initial exhaled breath can be introduced into the 19-expiratory bag 11.

[0023]

As described above, the exhaled breath from which the initial exhalation has been removed can be introduced into the exhalation bag, and the amount of CO ₂ required for analysis can be stably secured. In addition, since there is no contamination of the atmosphere, the isotope ratio of CO _{2 in} the breath to be analyzed can be obtained.

Using this breath collection tube, CO ₂ concentration of 3 to 5%
Was collected in a 2 liter breath bag, and an experiment was performed to determine how much the change was observed. As a result, the CO ₂ concentration was 3 to 5%, and the effect of removing the initial breath was confirmed.

[Brief description of the drawings]

FIG. 1 shows a cross-sectional view of a breath collection tube of an embodiment.

FIG. 2 shows a perspective view of each part of the breath collection tube shown in FIG.

FIG. 3 shows a cross-sectional view of a conventional breath collection tube.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 2 Silicon rubber stopper 3 Mouthpiece connection pipe 4 Mouthpiece 5 Silica gel 6 Expiration bag 7 Filter 8 Filter 10 T-shaped housing 11 Housing 12 Piston 13 Spring 14 Vent 15 Vent 16 Differential pressure check valve 17 Mouthpiece 18 Silica gel 19 Expiration bag 20 Filter 21 Filter 22 Flow path

Claims (1)

(57) [Claims] 1. A breath collection tube, wherein one end of a T-shaped casing 11 provided with a branch is connected to a mouthpiece 17 and the other end is connected to a breath bag 19 via a moisture absorbing part. A piston 12 which 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 expiration, a vent 14 for gradually discharging the initial expiration to the outside, and a flow for exhalation other than the initial expiration in the linear portion of the T-shaped housing. An exhalation collection tube comprising a passage (22) and a differential pressure check valve (16) for preventing backflow of exhaled air passing through the flow path (22) and operating at a pressure higher than a spring (13) returning the piston (12).