Van Liew H D, Conkin J, Burkard M E
Department of Physiology, University at Buffalo, SUNY 14214.
Aviat Space Environ Med. 1993 Sep;64(9 Pt 1):859-65.
The "oxygen window" causes a partial pressure difference of inert gas between the inside and outside of decompression bubbles. Estimates of Po2 and Pco2 in tissue are necessary for O2 window calculations and any calculations about growth or decay of decompression sickness bubbles, but the estimates involve many uncertainties. Using simplifying assumptions, we estimated the O2 window over a broad range of environments for tissues having a wide range of O2 extractions. The results were as follows: a) the window increases with ambient pressure, but levels off at very high pressure; b) the window is only 1 or 2 kPa for air breathing at extreme altitudes, and 200 kPa or more in hyperbaric environments; c) when O2 is breathed instead of air, the window is as much as 50 times larger at altitude but only about 10 times larger in hyperbaric environments; d) changes in bubble size due to the window decrease as barometric pressure increases; and e) there are seven additional factors which may supplement or oppose the action of the oxygen window.
“氧窗”导致减压气泡内外惰性气体存在分压差异。组织中氧分压（Po2）和二氧化碳分压（Pco2）的估算对于氧窗计算以及任何关于减压病气泡生长或消退的计算都是必要的，但这些估算存在诸多不确定性。我们通过简化假设，针对具有广泛氧摄取范围的组织，在广泛的环境范围内估算了氧窗。结果如下：a）氧窗随环境压力增加而增大，但在极高压力下趋于平稳；b）在极端海拔高度呼吸空气时，氧窗仅为1或2千帕，而在高压环境中则为200千帕或更高；c）当呼吸氧气而非空气时，在海拔高度氧窗增大多达50倍，但在高压环境中仅增大约10倍；d）随着气压升高，因氧窗导致的气泡大小变化减小；e）还有七个其他因素可能补充或抵消氧窗的作用。
