気道のダイナミックスに関する研究

Studies on Physiological Factors Affecting Airway Dynamics

はじめに

　気道のダイナミックスの評価は，いわゆる閉塞性肺疾患の診断のために重要な意義を有する。構造的破壊をともなう閉塞性肺疾患の早期診断のみならず，大気汚染や喫煙の影響による軽度の気道障害の検出についても関心がよせられている。このための臨床険査として，従来スパイログラフィーの強制呼出曲線から得られる1秒量，1秒率，MMFなどの指標が用いられてきたが，閉塞性障害の程度をより直接的に反映し，またより軽度な気道障害をも敏感に検出しうる気道抵抗，あるいは気道コンダクタンスの意義はとくに大きい。

　臨床的にこの指標を活用して気道障害を早期に検出するためには，その正常値，あるいは正常範囲の決定，ならびにこれに影響を及ぼす種々の因子の検討が重要な課題であろが，これらの問題についてまだ十分な検討を行なった報告は少ない。本研究はこれらの問題の検討を目的としたものである。

An empirical study was done to assess the physiological factors affecting specific airway conductance (Gaw (sp): airway conductance per unit lung volumes) of the human lung-thorax system.

Sixty-two male adults and eighteen female adults were chosen on the strict criteria as a healthy subject.

The multiple-factor analysis on Gaw (sp) was conducted. The parameters, such as body-height, age, smoking history and sex, were taken to make analysis.

In the present study the following results were obtained: 1) The relationship between the airway conductance and the lung volumes at endtidal level was different in the two male groups, under the age of 40 and above the age of 40, as well as in both sexes.

2) Gaw (sp) was correlated with body-height.

3) Gaw (sp) was inversely correlated with age, though this correlation was not signifi-cant.

The multiple regression equation of Gaw (sp) (L/sec/cmH₂O/L) in terms of body-height : H (cm) and age : A (yrs.) was obtained, Gaw (sp)=0.00130H-0.000219A+0.0352

4) In nonsmoker-group Gaw (sp) revealed a tendency to increase slightly with age, but in smoker-group, to decrease with age.

5) Gaw (sp) in the females was higher than that in the males.