DURING convulsions, cerebral metabolism increases and the brain's need for oxygen and substrate rises.1,2 At the same time, respiration ceases and this plus the intense muscle activity of the convulsion results in arterial blood hypoxia. To meet the increased metabolic demands of cerebral seizures, cerebral vessels dilate, systemic blood pressure increases,3 and cerebral blood flow rises.1,4,5 However, these compensating mechanisms cannot prevent brain hypoxia if the arterial blood is desaturated and, as a result, during a generalized convulsion cerebral venous and cortical oxygen tension decrease,6 cerebral energy stores are depleted,6,7 and brain lactate rises.6,7
The present study was undertaken to determine whether the compensatory increase in cerebral blood flow can protect the human brain against hypoxia during a cerebral seizure if apnea and muscle movement are eliminated. The study was begun after a previous study suggested that cerebral hypoxia does not occur during
Posner JB, Plum F, Van Poznak A. Cerebral Metabolism During Electrically Induced Seizures in Man. Arch Neurol. 1969;20(4):388–395. doi:10.1001/archneur.1969.00480100064010
Coronavirus Resource Center
Customize your JAMA Network experience by selecting one or more topics from the list below.