Prefaut C, Dubois F, Roussos C, Amaral-Marques R, Macklem P T, Ruff F
Respir Physiol. 1979 Aug;37(3):313-23. doi: 10.1016/0034-5687(79)90078-1.
We measured closing volume (CV), expiratory reserve volume (ERV) regional distribution of lung volume (Vr) and perfusion in 7 normal subjects in air and during immersion to the neck in water. In four subjects immersion resulted in a CV greater than ERV and the normal perfusion distribution became inverted. In the other subjects, ERV remained larger than CV and perfusion distribution during immersion was uniform, not inverted. In 5 subjects closing volume increased and in 3 of them, the ratio of apical/basal Vr increased significantly during immersion. One subject had nomeasurable CV and in the other it was not measured. The data suggest: (1) that when CV is greater than ERV during immersion there is an inversion of the normal perfusion distribution, caused by hypoxia and/or an increase in mean alveolar pressure in the alveoli beyond the closed airways, and (2) that an increase in pleural pressure gradient during immersion may contribute to the increase in C.V.
我们在7名正常受试者处于空气中以及颈部浸入水中时，测量了闭合气量（CV）、呼气储备量（ERV）、肺容积区域分布（Vr）和灌注情况。在4名受试者中，浸入水中导致CV大于ERV，正常的灌注分布发生倒置。在其他受试者中，ERV仍大于CV，浸入过程中的灌注分布均匀，未发生倒置。在5名受试者中，闭合气量增加，其中3名受试者在浸入过程中肺尖/肺底Vr比值显著增加。1名受试者的CV无法测量，另一名受试者未进行测量。数据表明：（1）浸入过程中当CV大于ERV时，正常灌注分布会发生倒置，这是由缺氧和/或封闭气道以外肺泡内平均肺泡压升高引起的；（2）浸入过程中胸膜压力梯度的增加可能导致闭合气量增加。
