Arieli R, Robicsek R
Israel Naval Medical Institute, Haifa, Israel.
J Basic Clin Physiol Pharmacol. 1996;7(2):83-96. doi: 10.1515/jbcpp.1996.7.2.83.
Our purpose if to develop a survival strategy for man trapped in a confined space. A previous study showed that in the rat there is a critical exposure time beyond which hypoxic survival improves. To evaluate the general applicability of these findings in the rat and the influence of body size, the effect of exposure time on hypoxic survival was studied in immature pigs (26 kg). The pig consumed the oxygen in a sealed chamber until hypoxic collapse. We measured blood pressure, oxygen consumption, inspired O2 and CO2, minute ventilation, ECG, body temperature, and PO2, PCO2 and pH in arterial and venous blood. Five groups of pigs were confined in different initial volumes of air, producing total exposure times of 0.5, 1.3, 2.3, 4.8 and 6.7 h. There was no significant difference between the experimental groups for any of the parameters measured during the exposure. Unlike the rat, in the pig there was no "adjustment time" beyond which the animal could survive to a lower PIO2. Terminal inspired PO2 increased as a function of exposure time. This was related to either hypoventilation or lung edema. There was a correlation between the level of carbon dioxide in the blood at 60-70 torr inspired oxygen and the terminal PO2. Pigs which failed to clear the carbon dioxide succumbed early to hypoxia. In a confined space it is preferable to maintain normoxic conditions for as long as possible.
我们的目的是为被困在密闭空间中的人制定一种生存策略。先前的一项研究表明，在大鼠中存在一个关键暴露时间，超过这个时间，低氧生存能力会提高。为了评估这些在大鼠中的研究结果的普遍适用性以及体型的影响，我们研究了暴露时间对未成熟猪（26千克）低氧生存的影响。猪在一个密封舱内消耗氧气，直到因低氧而虚脱。我们测量了血压、耗氧量、吸入的氧气和二氧化碳、分钟通气量、心电图、体温以及动脉血和静脉血中的氧分压、二氧化碳分压和pH值。五组猪被置于不同初始空气体积中，产生的总暴露时间分别为0.5、1.3、2.3、4.8和6.7小时。在暴露期间测量的任何参数在实验组之间均无显著差异。与大鼠不同，在猪中不存在一个“调整时间”，超过这个时间动物就能在更低的吸入氧分压下存活。终末吸入氧分压随暴露时间增加。这与通气不足或肺水肿有关。在吸入氧分压为60 - 70托时血液中的二氧化碳水平与终末氧分压之间存在相关性。未能清除二氧化碳的猪会较早死于低氧。在密闭空间中，最好尽可能长时间维持常氧条件。
