下体负压晕厥前症状时脑功能指标的变化特征

The characteristics of cerebral functional indices during occurrence of presyncopal symptom induced by lower body negative pressure

目的 探讨下体负压晕厥前症状 ( PSS)时头部血压 ( HBP)、颞动脉血流 ( TBF)、脑电 β2功率指数 ( PIβ2 )的变化特征 ,为飞行员加速度性晕厥的医学鉴定提供试验依据。 方法 用下体负压方法 ( L BNP)诱发 PSS,观察 HBP、TBF及 PIβ2 的变化特征。 结果 出现 PSS时 ,HBP由 ( 10 .0±0 .6 ) k Pa突降至 ( 3.6± 0 .5 ) k Pa,PIβ2 ( Oz电极 )由 ( 39.3± 8.4) %突降至 ( 2 3.2± 5 .2 ) % ,并与 HBP同步下降 (相关系数 t检验 P<0 .0 5 ) ,TBF近似中断。 结论 HBP是反映 PSS的稳定指标 ;PIβ2 在一定范围内直观反映 PSS期间的脑功能状态变化 ,但须参考 HBP;TBF对判断 PSS的发生有参考价值。

Objective To explore the characteristics of head blood pressure (HBP), temporal blood flow (TBF) and EEG power index β 2 (PIβ 2) during occurrence of presyncopal symptom (PSS) for providing experimental evidence in assessing pilots with +G Z intolerance. Methods Eight healthy young volunteers served as subjects. In the course of presyncopal limited lower body negative pressure (PSL LBNP) test, the HBP, TBF and PIβ 2 were recorded and analyzed. Results During the occurrence of PSS, HBP was lowered abruptly from (10.0±0.6) kPa to (3.6±0.5) kPa while PIβ 2 was synchronously decreased from (39.3±8.4)% to (23.2±5.2)% , and TBF was nearly held up. Conclusion It is suggested that HBP is a stable index reflecting occurrence of PSS, while PIβ 2 and TBF were indices of reference value for judging occurrence of PSS.