Probabilistic models of the role of oxygen in human decompression sickness

Probabilistic models of human decompression sickness (DCS) have been successful in describing DCS risk observed across a wide variety of N2-O2dives but have failed to account for the observed DCS incidence in dives with high P O 2 during decompression. Our most successful previous model, calibrated with 3,322 N2-O2dives, predicts only 40% of the observed incidence in dives with 100% O2 breathing during decompression. We added 1,013 O2 decompression dives to the calibration data. Fitting the prior model to this expanded data set resulted in only a modest improvement in DCS prediction of O2 data. Therefore, two O2-specific modifications were proposed: P O 2 -based alteration of inert gas kinetics (model 1) and P O 2 contribution to total inert gas (model 2). Both modifications statistically significantly improved the fit, and each predicts 90% of the observed DCS incidence in O2dives. The success of models 1 and2 in improving prediction of DCS occurrence suggests that elevated P O 2 levels contribute to DCS...