Effects of simulated fast buoyancy escape from 150 meters on blood cells and coagulation in goats following shallow water saturation exposure

Abstract

Objective To investigate the effects of simulated fast buoyancy escape from 150 meters (msw) on blood cells and coagulation in goats following shallow water saturation exposure. Methods Twelve adult male healthy goats were randomly divided into 2 groups: the 7-meter group and the 12-meter group, each consisting of 6 animals. The animals of the 2 groups breathing air were respectively exposed to the saturation pressures of 1.7 ATA (170 kPa) and 2.2 ATA (220 kPa) for 20 hours. Following saturation exposures, both groups underwent simulated fast buoyant escape from 150 msw. After the animals were surfaced and brought out of the chamber, clinical physical signs and pre-cordial bubble sound were closely observed, and morbidity and mortality of decompression sickness (DCS) were recorded. At hour 0.5 and 2 after they were out of the chamber, venous blood samples were collected for the measurement of blood cell counts as well as coagulation. Results No DCS and other injuries occurred in the animals of the 7-meter group, while in animals of the 12-meter group there were one case of pulmonary barotrauma and 6 cases of mild DCS. But there were no dead cases in both groups. As compared with that before compression[(17.27±0.93)s], the thrombin time (TT) of the 7-meter group at hour 0.5 and 2 after they were out of the chamber [ (18.38±0.77)s and(18.42±0.99)s] was all prolonged. The levels of fibrinogen(FIB)before compression, at hour 0.5 and 2 after they were out of the chamber were respectively[(2.36±0.53)g/L], [(2.63±0.69) g/L] and [(2.67±0.65)g/L]. Statistical significance could be noted, when comparisons were made between them(P<0.05). TP of the 12-meter group at hour 0.5 was obviously shortened, and statistical difference was shown when compared with that before compression(P<0.05). Nevertheless, TT level was recovered at hour 2 after they were out of the chamber. At hour 2 after the animals were out of the chamber, the activated partial thromboplastin time(APTT)and TT of the 12-meter group were all prolonged, and statistical significance could be found, when they were compared with that before compression(P<0.05). The level of D-dimer(D-D)for the 12-meter group at hour 2 after termination of exposure was significantly increased, as compared with that of the 7-meter group at the same time point. Statistical significance could be seen, when comparisons were made between them(P<0.05). Conclusions The study indicated that fast buoyancy escape from 150 meters following saturation exposure at depths of 7 and 12 meters could induce transient changes in coagulation and fibrinolysis activation, and might result in mild DCS. It was possible that fast buoyancy escape might be applied following saturation exposure at a depth shallower than 12 meters, which would of course depend on the situation. Key words: Saturation; Fast buoyancy escape; Goat; Coagulation; Fibrinolysis