Cerebral near-infrared spectroscopy to evaluate anti-G straining maneuvers in centrifuge training

摘要

Over the past decade, near-infrared spectroscopy (NIRS) has emerged as an easily manageable noninvasive method for the continuous monitoring of cerebral cortical oxygenation during 1 G z exposure. NIRS is also used to evaluate pilot trainees ' ability to adequately perform anti-G straining maneuvers in the course of centrifuge training. This study aimed to determine the general patterns and individual differences in NIRS recordings during 1 G z exposure. Methods: There were 22 healthy male cadets who participated in the study. The centrifuge training profiles included a gradual onset run (GOR, onset rate of 0.1 G z · s -1 ) and short-term repeated exposures, with G z levels from 4 to 7 G z at an onset rate of 1.0 G z ·s -1 (rapid onset run, ROR). Cortical tissue hemoglobin saturation (tissue oxygenation index, TOI) and changes in the concentration of oxygenated hemoglobin (O 2 Hb) were recorded from the right forehead during the period of G z exposure. Results: Most of the subjects successfully performed an anti-G straining maneuver and maintained or increased the cerebral oxygenation level during G z exposure. In four subjects, however, oxygenation decline was observed at levels over 4 G z, even though their anti-G systems were functioning. In contrast to the O 2 Hb response, TOI, which reflects intracranial oxygenation changes, was decreased during the anti-G straining maneuver at G z onset or during the countdown to a ROR exposure. Conclusion: Although NIRS is an effective tool for monitoring anti-G straining maneuver performance, it should be carefully evaluated in terms of intracranial oxygenation results. Reprint and