Method of Exhaled Gas Measurement and Analysis and Apparatus Therefor

Abstract

An exhalation collected in a breath bag capable of expanding and contracting is sucked into a gas inlet vessel 21 with a given volume (Va), and then the gas inlet vessel 21 is communicated by means of valve V2 with a cell 11 that is maintained at an atmospheric pressure by being pre-filled with a sample gas or reference gas. After the communication, the gas pressure is measured by a pressure sensor 16 attached to the cell 11. Whether the exhalation collected in the breath bag is below a given amount or not can be accurately judged.

Description

TECHNICAL FIELD[0001]Isotopic analyses are utilized for diagnosis of diseases in medical field, in which metabolic functions of a living body can be determined by administering an isotope-containing drug to the living body and then detecting a change in the concentration ratio of the isotopes.[0002]The present invention relates to a method of exhaled gas measurement and analysis and an apparatus for measuring the concentration of carbon dioxide 13CO2, or the concentration ratio of 13CO2 to 12CO2 in a human exhalation based on a difference in light absorption characteristic between isotopes.BACKGROUND ART[0003]The bacteria called Helicobacter Pylori (HP) are generally known as a cause of gastric ulcers and gastritis.[0004]If the HP is present in the stomach of a patient, an antibiotic or the like should be administered to the patient for bacteria removal treatment. Therefore, it is important to check if the patient has the HP. The HP has a strong urease activity for decomposing urea ...

AI Technical Summary

Benefits of technology

[0014]Therefore, it is an object of the present invention to provide a method of exhaled gas measurement and analysis and an apparatus used where an exhalation including carbon dioxide 13CO2 and carbon dioxide 12CO2 as component gases is introduced into a cell for measuring the concentrations of the respective component gases by infrared spectrophotometry, which are capable of accurately determining whether the obtained breath is less than the predetermined amount or not so as to prevent output of erroneous data.Means for Solving the Problems

[0016]According to this method, a predetermined volume of an exhalation of a patient is sucked into a gas inlet vessel and the pressure of the exhalation is measured to determine whether the amount of the exhalation collected in the breath bag is insufficient or not. Thus, the amount of the shortage of the exhalation can be determined with high accuracy. This can prevent output of data with poor reliability resulting from infrared spectrophotometry that is carried out with an insufficient amount of exhalation.

[0018]The arrangement may be such that after a predetermined volume of the exhalation collected in the breath bag is sucked into the gas inlet vessel, a valve is opened so that the gas inlet vessel is communicated with the inside of the cell that is maintained at the atmospheric pressure by being pre-filled with a prescribed gas, and the pressure of the gas after the communication is measured by a pressure sensor attached to the cell. In this case, measurement can be made utilizing the pressure sensor attached to the cell. Since the cell is usually provided with a pressure sensor, this pressure sensor can be utilized also for this purpose. Accordingly, it is not necessary to provide a pressure sensor directly attached to the foregoing gas inlet vessel, so that the structure of the apparatus can be simplified.

Problems solved by technology

However, the concentration ratio of 13CO2 to 12CO2 in naturally occurring carbon dioxide is 1:100, making it difficult to accurately determine the concentration ratio in the breath of the patient.

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