Cerebral physiology following general anesthesia with sevoflurane or propofol in healthy volunteers: a randomized, single-blind crossover trial.

Although general anesthesia is a very common medical procedure, knowledge of how the brain physiologically recovers remains limited. In this randomized crossover trial, we investigated brain physiology during recovery from general anesthesia with sevoflurane or propofol. Using magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS), we quantified cerebral blood flow (CBF), the cerebral metabolic rate of oxygen ([Formula: see text]), and concentrations of cerebral lactate and N-acetylaspartate before and after anesthesia. Twenty-one healthy volunteers [male:female 10:11, mean age 23 (18-32) yr] underwent two sessions of general anesthesia with either sevoflurane or propofol, spaced at least 4 wk apart. MRI scans were performed before anesthesia and again 4 h, 1 and 8 days after anesthesia. CBF increased by 5.7% at 4 h after sevoflurane general anesthesia (P = 0.040), possibly reflecting reduced hemoglobin concentration. [Formula: see text] and N-acetylaspartate concentrations did not change. In contrast, brain lactate was elevated 4 h after both sevoflurane (14.7%, P = 0.0006) and propofol (9.5%, P = 0.01), and remained elevated 1 day after sevoflurane anesthesia (13.2%, P = 0.0008). This lactate increase occurred despite normal [Formula: see text] and may indicate enhanced glycolytic activity during postanesthetic recovery.NEW & NOTEWORTHY We examined the sustained effects of general anesthesia with sevoflurane or propofol on brain physiology in healthy adults, given the limited understanding of how the brain physiologically recovers from anesthesia. Cerebral metabolic rate of oxygen was unchanged in the hours after anesthesia and remained stable over subsequent days. In contrast, brain lactate increased after anesthesia and stayed elevated into the next day. No substantial differences were observed between anesthetic agents.