Bitterman N, Laor A, Melamed Y
Israel Naval Hyperbaric Institute, Haifa.
Undersea Biomed Res. 1987 Nov;14(6):477-83.
Central nervous system oxygen toxicity in hyperbaric oxygen-inert gas mixtures was studied by exposing male rats to various gas mixtures having the same oxygen partial pressure and varying pressures of inert gases. The duration of the latent period until the appearance of electrical discharges in the electroencephalogram was used as the criterion for the sensitivity to CNS oxygen toxicity. Two hundred and twenty rats with chronically implanted cortical electrodes were subjected to a single exposure to 1 of 11 different gas mixtures at ambient pressures ranging from 5 to 10 ATA. All gas mixtures had a constant oxygen partial pressure of 5 ATA and varying pressures of inert gas (helium or nitrogen). The duration of the latent period was found to be significantly different in the 11 experimental groups (P less than 0.001). While increasing the inert gas pressure, the latency gradually shortened, reaching the lowest values in mixtures of 5 ATA oxygen and 3 ATA of either inert gas. On further increase in the inert gas pressure up to a total ambient pressure of 10 ATA, the latency returned to control (pure 5 ATA oxygen) values. No difference was found between nitrogen and helium of equal partial pressures. These findings suggest that the risk of CNS oxygen toxicity in gas mixtures is not determined solely by the PO2, and even a relatively low pressure of inert gas can contribute to the imminence of hyperbaric-oxygen-induced seizures.
通过将雄性大鼠暴露于具有相同氧分压和不同惰性气体压力的各种气体混合物中，研究了高压氧 - 惰性气体混合物中的中枢神经系统氧中毒。脑电图中出现放电之前的潜伏期持续时间被用作对中枢神经系统氧中毒敏感性的标准。220只长期植入皮质电极的大鼠在5至10个绝对大气压的环境压力下单次暴露于11种不同气体混合物中的一种。所有气体混合物的氧分压均为5个绝对大气压，惰性气体（氦气或氮气）的压力不同。发现11个实验组的潜伏期持续时间有显著差异（P小于0.001）。随着惰性气体压力的增加，潜伏期逐渐缩短，在5个绝对大气压氧气与3个绝对大气压任何一种惰性气体的混合物中达到最低值。当惰性气体压力进一步增加至总环境压力10个绝对大气压时，潜伏期恢复到对照（纯5个绝对大气压氧气）值。发现等分压的氮气和氦气之间没有差异。这些发现表明，气体混合物中中枢神经系统氧中毒的风险并非仅由氧分压决定，即使相对较低压力的惰性气体也可能导致高压氧诱发癫痫发作的紧迫性增加。
