RESUMO
INTRODUCTION: The Doppler technique is currently the usual method for detection of bubbles in the circulation following decompression. However, cases of decompression sickness (DCS) frequently occur in the absence of detectable bubbles, so that other markers for increasing risk of DCS would be welcome. This study assessed the hemostatic effects of compressed-air saturation dives that conformed to the "safe" limits of accepted decompression tables. METHODS: We measured coagulation times, thrombin generation, platelets, and fibrinolysis in 21 male divers who were subjected to saturated hyperbaric exposures to 0.28-0.3 MPa (corresponds to 18-20 msw). Each diver did one dive. RESULTS: Pooled before- and after-dive data for all exposures showed after decompression, statistically significant changes included decrease of the mean platelet count after, increased induced platelet aggregation and number of platelet aggregates, increased number of P-selectin (CD62P) positive platelets and CD62P density on platelets, increase of platelet derived microparticles in the blood of the divers, decrease of factor XII, X, and fibrinogen concentrations, and marked increase of plasmin-antiplasmin complex concentration. Thrombin activation markers and coagulation times did not change significantly. CONCLUSIONS: Saturated hyperbaric exposures followed by nominally safe decompression led to activation of platelets and the fibrinolytic system. The probable mechanism for the activation of platelets and fibrinolysis is contact with the surface of evolved bubbles in the divers' circulation.