Anesthetics, alcohols, and purines

21_05
Oxygen toxicity limits in human beings. The two areas most affected are the CNS and the lungs. The occurrence of toxicity depends upon both the inspired oxygen pressure (PO2) and the duration of exposure. The safe duration of exposure becomes shorter as the inspired PO2 increases. Below 0.5 atmosphere of inspired oxygen, indefinite exposure appears to be safe; between 0.5 and approximately 2 atmospheres, pulmonary toxicity occurs after prolonged exposures but CNS effects are not detectable; above 2 atmospheres, CNS toxicity appears before pulmonary effects are detectable.