Influence of oxygen hyperbaria on the activity of complement in human's sera

Studies on the effect of hyperbaric oxygenation on serum complement activity were carried out in 133 young men aged 20--22 years, quartered and given the same board. For this purpose the 50% hemolysis method was used, the determinations being made prior to the hyperbaric exposure and 72 hours, 5 days and 10 days thereafter. The exposure took place in a pressure chamber, where the respective groups studied underwent a 60 min oxygenation at normal pressure, highpressure oxygenation at 2.8 atmospheres and the effect of the air at the same pressure. For proper assessment of the results the studies were also performed in candidates for divers and frogmen, in trained divers and frogmen and in control, non-diving subjects in whom only complement activity determinations were made. It was found, that in the subjects who were never previously exposed to the effect of hyperbaric conditions, a rise in the complement activity occurred subsequently to the exposure to high-pressure oxygenation at 2.8 atmospheres; the complement level returned to normal limits within 10 days.