COMPLEMENT ACTIVATION DURING SATURATION DIVING

In this study, the levels of activated complement fragments C3a and C5 a were measured on 11 U.S. Navy divers as they performed a 28-day satu ration dive to a pressure equivalent of 1,000 feet of seawater (fsw, 3 1.3 atm abs). Two subjects developed symptoms consistent with the high pressure nervous syndrome (HPNS) and three were treated for type I DC S (joint pain only). These events allowed us to test two hypotheses: a ) alterations in C3a or C5a levels during compression are related to t he occurrence of HPNS and b) increases in complement fragments are an indicator of decompression stress associated with type I DCS. There wa s no correlation between changes in C3a and C5a levels during compress ion and the diagnosis of HPNS. Our results suggest that an increase in C3a and C5a levels during saturation diving correlates with decompres sion stress and the clinical diagnosis of type I DCS.