Effect of simulated hypoxic exposure on cerebral blood perfusion of pilots

Objective To provide physiological basis of cerebral function identification of pilots in hypoxic environment by observing the pilots' cerebral blood perfusion characteristics before and after hypoxic exposure. Methods Thirty-five healthy male pilots were subjected to normal and hypoxic exposure that the oxygen concentration was 14.5%. We inspected the cerebral blood perfusion by arterial spin labeling technology and compared the differences between the two states. Results After hypoxic exposure, the pulse was (63.97±10.43) beats/min (t=4.969, P<0.01), it was lower than before which was (71.46±10.63) beats/min. The oxygen saturation was (92.46±3.64)%, it was lower than before which was (96.31±1.23)% (t=6.437, P<0.01). Arterial spin labeling (ASL) in pilots after hypoxic exposure showed lower cerebral blood flow (CBF) values prominently in the following regions: the bilateral superior temporal gyrus, the bilateral middle temporal gyrus, the left inferior temporal gyrus, the right middle occipital gyrus, the right inferior occipital gyrus, the bilateral lingual gyrus, the right fusiform gyrus, the right cuneus and cerebellum (P<0.05). Conclusions The cerebral blood perfusion after hypoxic exposure is decreased mainly in the temporal and occipital lobe for the right side, and arterial spin-labeling technique can monitor CBF changes of the pilots in hypoxic exposure. Key words: Magnetic resonance imaging; Anoxia; Cerebrovascular circulation; Pulsatile flow; Hemoperfusion; Pilots