BACKGROUND: Recent increases in use of sevoflurane have made active researches on its effects in the cerebral metabolism. However, no specific data on brain glucose metabolism has been reported from human study. We compared the brain glucose metabolism during sevoflurane anesthesia with that of propofol anesthesia using positron emission tomography (PET) in the same human volunteers.

METHODS: PET scan was performed two times at intervals of one week in each eight volunteers. One scan was performed in sevoflurane anesthesia, and the other was performed in propofol anesthesia. Each was titrated to the point of unconsciousness. The scan was obtained by the 18fluorodeoxyglucose technique. Relative cerebral glucose metabolic rate (rCMRg) was assessed with statistical parametric mapping.

RESULTS: The regions of decreased rCMRg during sevoflurane aneshesia were the visual cortex, posterior parietal association area, primary somatosensory area, and premotor area. During propofol anesthesia the decreased regions were the visual inferotemporal area and prefrontal association area in addition to those area of sevoflurane anesthesia. The increased regions were the partial prefrontal association area, basal ganglia, cingulate, olfactory-limbic cortex, midbrain, and pons during sevoflurane anesthesia, and the primary motor area, insula, thalamus, medulla along with those area of sevoflurane during propofol anesthesia.

CONCLUSION: Propofol suppressed the rCMRg of neocortex area more than sevoflurane, and sevoflurane suppressed the rCMRg of paleocortex, telencephalon more than propofol when the unconsciousness level was achieved by anesthesia. Sevoflurane produces different effects on relative brain glucose metabolism with propofol.