最大通气量、时间肺活量和最大呼气中段流速等,均是测定气道阻塞的方法,其优点是设备简单,操作方便。但多年临床实践证明,它们对阻塞性肺病的早期诊断帮助不大,甚至细气道阻塞已经引起通气血流失调、呼吸道症状已很明显,但测验结果仍在正常范围。周围细气道虽然管径小,容易狭窄阻塞,但分枝多、总断面积大,故其阻力反小于大气道。在较小的肺容量(呼气至肺活量的10～20%),细气道阻力最大时,亦仅占总气道阻力的10～20%以下。近10余年来国外探索细气道阻塞的测定方法,闭合气量(Closing Volume,简称CV)即是其中之一。近年国内亦开展这项测验。本文综述国外有关资料,就闭合气量的生理基础、测验方法、常数和临床应用等方面,扼要介绍,以供参考。 Maximum ventilation, time vital capacity and maximum expiratory flow in the middle, etc., are measured airway obstruction method, which has the advantage of simple equipment, easy operation. However, years of clinical practice have proved that they are not helpful for the early diagnosis of obstructive pulmonary disease. Even the airway obstruction has caused the imbalance of ventilation and blood flow, and the respiratory symptoms have been very obvious. However, the test results are still in the normal range. Although the small airways around the small diameter, easy to narrow obstruction, but more branches, the total cross-sectional area, so the resistance is less than the air channel. In the smaller lung volume (expiratory to vital capacity of 10 to 20%), the greatest airway resistance, also accounted for only 10 to 20% of the total airway resistance below. Nearly 10 years abroad to explore the determination of small airway obstruction, closed volume (Closing Volume, referred to as CV) is one of them. In recent years, this test is also conducted in China. This article summarizes the relevant foreign information on the physiological basis of closed gas, test methods, constants and clinical applications, etc., briefly introduced for reference.