Reed J W, Elliott C, Thorsen E
Department of Physiological Sciences, University of Newcastle upon Tyne Medical School, United Kingdom.
Undersea Hyperb Med. 2001 Spring;28(1):19-23.
With deep saturation diving a reduction in vital capacity caused by oxygen toxicity may be opposed by a training effect of respiratory muscles due to increased gas density and work of breathing. We measured lung and chest wall mechanics before and after a 28-day saturation dive to a pressure of 0.25 MPa with the same profile of oxygen exposure as in a deep dive to a pressure of 3.7 MPa; 40 kPa during the isopression phase and 50 kPa during the decompression phase. Eight males aged 22-28 yr served as subjects. The measurements included dynamic lung volumes, static lung compliance, lung recoil pressure, and maximal respiratory pressures. Only one subject had decreased lung compliance and increased recoil pressure after the dive. The others had an increase in compliance and decrease in recoil pressure. There was a significant increase in inspiratory lung compliance (P = 0.041) and a trend for a decrease in lung recoil pressure (P = 0.061). We found no change in forced vital capacity, but decreases in forced expired volume in 1 s (P = 0.049) and forced midexpiratory flow rate (P = 0.009) were noted. There were no changes in maximal respiratory pressures. These findings are opposite to the classical findings associated with pulmonary oxygen toxicity. The results may reflect an increase in surfactant production and turnover as an early adaptive response to hyperoxic stress.
在深度饱和潜水过程中，由氧中毒导致的肺活量降低可能会被呼吸肌的训练效应所抵消，这种训练效应是由于气体密度增加和呼吸功增加所致。我们在一次为期28天、压力为0.25兆帕的饱和潜水前后测量了肺和胸壁力学，其氧暴露情况与深度为3.7兆帕的潜水相同；等压阶段为40千帕，减压阶段为50千帕。8名年龄在22 - 28岁的男性作为受试者。测量内容包括动态肺容量、静态肺顺应性、肺回缩压和最大呼吸压力。潜水后只有一名受试者的肺顺应性降低且回缩压增加。其他受试者的顺应性增加且回缩压降低。吸气肺顺应性显著增加（P = 0.041），肺回缩压有降低趋势（P = 0.061）。我们发现用力肺活量没有变化，但1秒用力呼气量（P = 0.049）和用力呼气中期流速（P = 0.009）降低。最大呼吸压力没有变化。这些发现与经典的肺氧中毒相关发现相反。结果可能反映了表面活性剂产生和更新增加，这是对高氧应激的一种早期适应性反应。
