Moon R E, Cherry A D, Stolp B W, Camporesi E M
Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA.
J Appl Physiol (1985). 2009 Feb;106(2):668-77. doi: 10.1152/japplphysiol.91104.2008. Epub 2008 Nov 13.
Diving-related pulmonary effects are due mostly to increased gas density, immersion-related increase in pulmonary blood volume, and (usually) a higher inspired Po(2). Higher gas density produces an increase in airways resistance and work of breathing, and a reduced maximum breathing capacity. An additional mechanical load is due to immersion, which can impose a static transrespiratory pressure load as well as a decrease in pulmonary compliance. The combination of resistive and elastic loads is largely responsible for the reduction in ventilation during underwater exercise. Additionally, there is a density-related increase in dead space/tidal volume ratio (Vd/Vt), possibly due to impairment of intrapulmonary gas phase diffusion and distribution of ventilation. The net result of relative hypoventilation and increased Vd/Vt is hypercapnia. The effect of high inspired Po(2) and inert gas narcosis on respiratory drive appear to be minimal. Exchange of oxygen by the lung is not impaired, at least up to a gas density of 25 g/l. There are few effects of pressure per se, other than a reduction in the P50 of hemoglobin, probably due to either a conformational change or an effect of inert gas binding.
与潜水相关的肺部影响主要归因于气体密度增加、与浸入相关的肺血容量增加以及（通常）较高的吸入氧分压。较高的气体密度会导致气道阻力增加和呼吸功增加，以及最大呼吸能力降低。浸入会带来额外的机械负荷，它可施加静态跨呼吸压力负荷以及肺顺应性降低。阻力负荷和弹性负荷的共同作用在很大程度上导致了水下运动时通气量的减少。此外，死腔/潮气量比值（Vd/Vt）会因密度相关因素而增加，这可能是由于肺内气相扩散和通气分布受损所致。相对通气不足和Vd/Vt增加的最终结果是高碳酸血症。高吸入氧分压和惰性气体麻醉对呼吸驱动的影响似乎很小。至少在气体密度达到25克/升之前，肺的氧交换不会受到损害。除了血红蛋白P50降低外，压力本身几乎没有其他影响，这可能是由于构象变化或惰性气体结合的作用。
