Power equation for all-or-none effects of oxygen toxicity and cumulative oxygen toxicity.
Quantification of the level of O2 toxicity may provide a means of setting limits on various hyperoxic exposures. A previously suggested expression for quantitative oxygen toxicity, DMG = a x t2 x PO2c (t-time, DMG-measured level of O2 toxicity), has been adapted for the all-or-none phenomenon: K = t2 x PO2c. A symptom may appear when K reaches a threshold value Kc. Non-linear regression was successfully applied to all-or-none symptoms from the literature: survival, convulsions, substernal distress, reduction in short circuit current and nerve conduction blockade. The generality of these expressions enabled calculation of cumulative oxygen toxicity and a search for the mechanism of oxygen toxicity. Cumulative oxygen toxicity is calculated in three-step calculation loops in three suggested exposure profiles. For a possible recovery period between exposures the expressions took the form: DMGt = DMGc x e-rt, and Kt = Kc x e-rt, where r is the recovery constant. A possibly bimodal distribution of c close to the values of 1 and 4 could be attributed to systemic effects.
Arieli
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Israel Naval Medical Institute, Haifa, Israel.
D000818:Animals; D006801:Humans; D018496:Hyperoxia / Q000378:metabolism*; D007700:Kinetics; D051379:Mice; D008815:Mice, Inbred Strains; D010100:Oxygen / Q000633:toxicity*; D051381:Rats; D013997:Time Factors
D010100:Oxygen