Van der Worp H B, Kraaier V, Wieneke G H, Van Huffelen A C
Department of Clinical Neurophysiology, University Hospital Utrecht, The Netherlands.
Electroencephalogr Clin Neurophysiol. 1991 Nov;79(5):335-41. doi: 10.1016/0013-4694(91)90197-c.
To investigate the role of cerebral hypoxia as a causative factor in the alteration of the qEEG during hyperventilation, qEEG changes caused by progressive hypocapnia were compared with qEEG changes due to progressive normobaric hypoxia in two parallel groups of 12 and 10 healthy male subjects (age 20-27 years), respectively. In the first group, qEEG records were obtained before and during hyperventilation to pCO2 levels of 4.0, 3.0 and 2.0 kPa. In the second group, the qEEG samples were taken before and during hypoxia with hemoglobin oxygen saturations of 80, 70 and 60%. In both groups, blood flow velocity in the middle cerebral artery was also recorded. Hyperventilation caused an exponential increase in slow activity and a decrease in alpha power. No shift in the alpha mean frequency and alpha peak frequency was observed, except with the pCO2 level of 4.0 kPa, which caused an increase in both variables. Hypoxia with a hemoglobin oxygen saturation of 60% caused a much less pronounced increase in slow activity. No change in total power in the alpha band was found, but both the alpha peak frequency and alpha mean frequency decreased. Lesser degrees of hypoxia caused only minimal EEG changes. Blood flow velocity was decreased by hyperventilation but increased by hypoxia. It is concluded that the EEG changes observed during hyperventilation must mainly or totally be attributed to factors other than cerebral hypoxia.
为研究脑缺氧在过度通气期间定量脑电图（qEEG）改变中的致病作用，分别在两组平行的12名和10名健康男性受试者（年龄20 - 27岁）中，比较了渐进性低碳酸血症引起的qEEG变化与渐进性常压缺氧引起的qEEG变化。在第一组中，在过度通气至二氧化碳分压（pCO2）水平为4.0、3.0和2.0 kPa之前及期间获取qEEG记录。在第二组中，在血红蛋白氧饱和度为80%、70%和60%的缺氧之前及期间采集qEEG样本。在两组中，还记录了大脑中动脉的血流速度。过度通气导致慢波活动呈指数增加和α波功率降低。除pCO2水平为4.0 kPa时导致两个变量均增加外，未观察到α波平均频率和α波峰值频率的偏移。血红蛋白氧饱和度为60%的缺氧导致慢波活动增加的程度要小得多。未发现α频段总功率变化，但α波峰值频率和α波平均频率均降低。程度较轻的缺氧仅引起最小程度的脑电图变化。过度通气使血流速度降低，而缺氧使其增加。得出的结论是，过度通气期间观察到的脑电图变化主要或完全归因于脑缺氧以外的因素。
