Fairshter R D, Berry R B, Lowe J E
University of California, Irvine, Medical Centre, Orange, California 92668.
Bull Eur Physiopathol Respir. 1987 Sep-Oct;23(5):449-55.
We evaluated the effects of inhomogeneous lung emptying on the relationship of partial to maximal complete expiratory flow by obtaining pre- and post-metaproterenol maximal (MEFV) and partial flow-volume curves in normal subjects and asthmatics. Partial curves were initiated between 65-70% of vital capacity after inspiration from functional residual capacity (PEFV curve) or after deflation from total lung capacity (PEFVDI curve). Since PEFVDI curves were initiated at lower lung volumes than MEFV manoeuvres (but with a similar volume history), non-homogeneous emptying should cause higher flow on PEFVDI than on MEFV manoeuvres. Expiratory flow (Vmax) was highest on MEFV manoeuvres in normals and PEFV curves in asthmatics. Pre- and post-metaproterenol Vmax was very similar on MEFV and PEFVDI manoeuvres in both groups, although Vmax(MEFV) slightly but significantly exceeded Vmax(PEFVDI) in normals and the reverse was true in asthmatics. Lung elastic recoil did not differ significantly on MEFV and PEFVDI manoeuvres in either group. We conclude that asthmatics demonstrate inhomogeneous emptying. However, because flow-volume curves are relatively insensitive to sequences of lung emptying, inhomogeneous emptying during forced expiration only has minor effects on the relationship of partial to maximal expiratory flow.
我们通过获取正常人和哮喘患者在使用间羟异丙肾上腺素前后的最大呼气流量容积（MEFV）曲线和部分流量容积曲线，评估了肺排空不均匀对部分呼气流量与最大完全呼气流量关系的影响。部分曲线是在从功能残气量吸气后肺活量的65%-70%之间起始（PEFV曲线），或从肺总量放气后起始（PEFVDI曲线）。由于PEFVDI曲线起始时的肺容积低于MEFV操作时的肺容积（但有相似的容积变化过程），不均匀排空应导致PEFVDI上的流量高于MEFV操作时的流量。正常人的MEFV操作和哮喘患者的PEFV曲线上呼气流量（Vmax）最高。两组中，间羟异丙肾上腺素使用前后MEFV和PEFVDI操作时的Vmax非常相似，尽管正常人中Vmax(MEFV)略高于但显著高于Vmax(PEFVDI)，而哮喘患者情况相反。两组中MEFV和PEFVDI操作时肺弹性回缩力无显著差异。我们得出结论，哮喘患者表现出不均匀排空。然而，由于流量容积曲线对肺排空顺序相对不敏感，用力呼气时的不均匀排空对部分呼气流量与最大呼气流量的关系仅产生轻微影响。
