Prabhu M B, Mink J T, Graham B L, Cotton D J
Department of Medicine, University of Saskatchewan, Saskatoon, Canada.
Respir Physiol. 1990 Mar;79(3):195-204. doi: 10.1016/0034-5687(90)90126-j.
We examined the effect of a previous deep breath on both inert gas mixing and the single breath diffusing capacity (DLCOSB) during submaximal single breath maneuvers in normal subjects. Single breath washouts were performed either immediately after a deep breath or after breathing tidally for 10 min. Maneuvers consisted of inhaling test gas from functional residual capacity to 50% inspiratory capacity and, after either 0 or 6 s of breath holding, exhaling slowly back to residual volume. We measured the Fowler dead space, the Phase III slope of the alveolar plateau of the He washout (delta He/L), the amplitude of the cardiogenic oscillations (Oc), closing capacity, mixing efficiency (Emix) and DLCOSB using the three equation method. For maneuvers immediately after a deep breath we found that delta He/L was steeper and the Oc were larger for washouts with 6 s but not 0 s of breath holding, while Emix was significantly lower and DLCOSB significantly higher for both the 0 s and the 6 s breath holding maneuvers. We conclude that a deep breath increases DLCOSB but simultaneously also increases convective-dependent inhomogeneity in the lung.
我们研究了在正常受试者次极量单呼吸动作期间，先前深呼吸对惰性气体混合及单次呼吸弥散量（DLCOSB）的影响。单呼吸冲洗操作在深呼吸后立即进行，或在潮式呼吸10分钟后进行。操作包括从功能残气量吸入测试气体至吸气量的50%，并在屏气0秒或6秒后，缓慢呼气至残气量。我们使用三方程法测量了Fowler死腔、氦气冲洗时肺泡平台的III期斜率（δHe/L）、心源性振荡幅度（Oc）、闭合容量、混合效率（Emix）和DLCOSB。对于深呼吸后立即进行的操作，我们发现屏气6秒而非0秒的冲洗中，δHe/L更陡且Oc更大，而对于屏气0秒和6秒的操作，Emix均显著降低，DLCOSB显著升高。我们得出结论，深呼吸会增加DLCOSB，但同时也会增加肺内对流依赖性的不均匀性。
