[Effect of flight factors on changes in blood coagulation and anticoagulation indices in crew members]

A total of 105 flight qualified crewmembers, aged 20 to 40, were taken under observation. Coagulographic and thromboelastographic parameters of the venous blood were studied. The most significant changes (an increase in the coagulation time as related to the time of plasma recalcification, a decrease of the plasma tolerance to heparin, R, K, R plus K, a decrease in the coagulation index Si with respect to the thromboelastogram, a significant increase in the fibrinolytic activity and the heparin number) were noted postflight in commanders, pilots and navigators. Less significant variations of the coagulographic parameters were observed in other crewmembers. The above changes (an increase in endogenous heparin, an acceleration of the fibrinolytic activity) can be regarded as the protective-adaptive reaction of the anticoagulatory system aimed at reducing hypercoagulation during the emotional stress-effect of the flight.