高性能战斗机飞行员脑应激疲劳时脑平均血流速度变化特征与立位耐力关系研究

目的 为飞行员心脑功能鉴定提供试验方法和依据.方法 测试45名男性飞行员(平均年龄27.5±2.6岁)在完成5 h"连续操作"任务期间,大脑前动脉(ACA)、大脑中动脉(MCA)和大脑后动脉(PCA)的脑平均血流速度(Vm),同步分析Vm、立位耐力与心脑功能指标间的变化关系,并对持续认知操作活动诱发的脑应激疲劳(CFS)进行斯坦福嗜睡量表(SSS)评定.结果 从第4 h以后,PCA的Vm先于ACA、MCA显著下降(t=9.254、11.918,P<0.05),出现晕厥前症状(PSS)时,ACA、MCA、PCA的Vm和立位耐力同时降低(t=9.314、11.654、15.120、20.545,P<0.05).脑电功率指数、心率变异性、连续操作能力指数测试及SSS主观评定表明心脑功能出现了严重抑制.结论 CFS末期,出现PSS时,ACA、MCA、PCA的Vm与立位耐力同步下降.CFS可诱发PSS或立位耐力降低.

The relationship between mean cerebral blood velocity and orthostatic tolerance of high performance fighter pilots under cerebral fatigue in stress

Objective To provide the evidences and methods for assessing pilot's cardio-cerebral function. Methods Forty-five male pilots (average age was 27.5±2.6 years) were selected as subjects. Cerebral mean blood velocities (Vm) of anterior cerebral artery (ACA), middle cerebral artery (MCA) and posterior cerebral artery (PCA) were measured in the "consecutive operation task" for 5 h by transcranial Doppler ultrasonography. Cerebral fatigue in stress (CFS) that induced by consecutive operation tasks was evaluated by Stanford sleepiness scales (SSS). Such parameters as blood pressure (related to orthostatic tolerance), Vm, neurobehavioral ability index (NAI), electroencephalogram power index β_2 (PIβ_2), heart rate variability (HRV) and scores of SSS were compared individually. Results When performing consecutive operation task for 4 h, Vm of PCA declined significantly earlier than that of ACA and MCA (t=9.254, 11.918, P<0.05). When pre-syncope symptom (PSS) occurred, orthostatic tolerance and Vm of ACA, MCA and PCA declined simultaneously (t=9.314, 11.654, 15.120, 20.545, P<0.05). The test results of PIβ2, HRV, NAI and subjective assessment of SSS indicated the serious depression of cardio-cerebral functions. Conclusions At the end of CFS, the Vm of ACA, MCA and PCA are synchronously declined with orthostatic tolerance when PSS occurred. CFS may induce PSS and orthostatic intolerance.