A positron emission tomography study of cerebral blood flow and oxygen metabolism in healthy male volunteers anaesthetized with eltanolone

Publisher Website
Google Scholar
Abstract
Background: The effects of eltanolone anaesthesia in humans on regional cerebral blood flow, regional cerebral metabolic rate of oxygen and oxygen extraction ratio were to be evaluated using positron emission tomography (PET). Methods: Six healthy male volunteers were studied. Series of PET-measurements with 15O and H215O were carried out in the awake state (baseline) (n=6), during eltanolone anaesthesia (n= 5) and during early recovery (n=5), when the subjects were oriented with respect to person, place and time. Eltanolone was given as a programmed infusion. Results: Cerebral blood flow (rCBF) was reduced in almost all cortex regions studied by 31216% (meanSD, P < 0.01). During recovery KBF increased to 10926% of pre-anaesthetic baseline levels (P < 0.01). Eltanolone in the doses administered lowered oxygen metabolism (rCMRO2) by 528% (P < 0.01) in cortex regions. During recovery rCMRO2 increased to 9013% of baseline (P < 0.01). The oxygen extraction (OER) in cortical regions decreased by 32223% (P < 0.01) during anaesthesia and returned to 82210% of baseline (P < 0.01) during recovery. Less reduction in cortical blood flow during eltanolone anaesthesia was seen in the uncus (P < 0.01), though no differences in the depression of oxygen metabolism were seen. Oxygen extraction remained homogeneous throughout the brain. Conclusion: Eltanolone anaesthesia was shown to reduce cerebral oxygen metabolism and cerebral blood flow in healthy volunteers. There were no signs of ischaemic effects.