本测验是一种简单而灵敏的肺功能检查,能发现常规肺功能检查不能探出的肺功能变化。此法是Fowler方法的改良,除可测定通气的分布情况及无效腔外,还可测定肺总量、余气量、闭合气量(closing volume)及闭合容量(closing capacity=闭合气量+余气量)。测验步骤是在一次深吸氧后进行一次缓慢的深呼气,同时测定并描记呼出气中氮的浓 This test is a simple and sensitive examination of lung function that can detect changes in lung function that routine pulmonary function tests can not detect. This method is an improvement of the Fowler method. In addition to determining the distribution of ventilation and invalid cavity, the lung volume, residual volume, closing volume and closing capacity can be determined. The test procedure is to conduct a deep, deep breath after a deep oxygenation while measuring and characterizing the concentration of nitrogen in exhaled breath