Meyer M, Rieke H, Hook C, Piiper J
Department of Physiology, Max Planck Institute for Experimental Medicine, Göttingen, F.R.G.
Respir Physiol. 1989 Jul;77(1):65-73. doi: 10.1016/0034-5687(89)90030-3.
Simultaneous washout of He and SF6 was studied in anesthetized paralyzed dogs (mean body weight 19 kg) subjected to high-frequency ventilation at varying frequencies (10-40 Hz), stroke volumes (20-40 ml), lung volumes (0.8-1.2 L) and fresh gas flow rates (7-13 L/min). The washout curves could be analyzed into three exponential components for both test gases. The rate constants of the intermediate and slow components were slightly but significantly higher for He than for SF6 while the fast component was the same for the two test gases. The data were analyzed on the basis of a series lung model with a dead space compartment and two serially arranged alveolar compartments. The He/SF6 ratio of the effective conductances for gas transfer between the alveolar compartments averaged 1.15 +/- 0.08 (SD). Since this ratio is much closer to unity, predicted for convective transport, than 6 to 7, predicted for diffusive transport, it is concluded that during high-frequency ventilation gas transport in peripheral airways occurs by both convection and diffusion, convection being quantitatively more important.
在体重平均为19千克、处于麻醉状态且瘫痪的犬类中，研究了在不同频率（10 - 40赫兹）、潮气量（20 - 40毫升）、肺容积（0.8 - 1.2升）和新鲜气流速（7 - 13升/分钟）下进行高频通气时氦气和六氟化硫的同时洗脱情况。两种测试气体的洗脱曲线均可分析为三个指数成分。氦气的中间成分和缓慢成分的速率常数略高于六氟化硫，但差异显著，而快速成分在两种测试气体中相同。数据基于具有死腔隔室和两个串联排列的肺泡隔室的串联肺模型进行分析。肺泡隔室之间气体传输的有效传导率的氦气/六氟化硫比率平均为1.15±0.08（标准差）。由于该比率比扩散传输预测的6至7更接近对流传输预测的1，因此得出结论，在高频通气期间，外周气道中的气体传输通过对流和扩散两种方式发生，对流在数量上更为重要。
