Inhalational induction with "vasoparalytic" sevoflurane: are we "hyperoxygenating" while anesthetizing developing brains? A case series discussion.

The concerns for hyperoxia-related brain tissue injury are well known to the medical community. The cerebro-vasodilatory properties of sevoflurane may create relative cerebral tissue "hyperoxia" during inhalational induction as compared to a propofol-based intravenous induction of anesthesia. The objective for this case series discussion was to identify any differences in cerebral tissue oxygenation secondary to induction of anesthesia with sevoflurane versus propofol. METHODS/STUDY PROCEDURES: After institutional review board approval, the computer data of tissue cerebral oximetry of pediatric patients (1-18 years age group) undergoing non-cardiac surgeries was comparatively analyzed for changes over time between the groups of children who received sevoflurane induction versus propofol induction of anesthesia. "Hyperoxia" ("hyperoxygenation") was defined as significant percent changes from the baseline values as recorded in tissue cerebral oximetry. In this case series, seven patients underwent inhalational (INH) induction with high concentrations (8%) sevoflurane with nitrous oxide in 33% oxygen and four patients underwent intravenous (i.v.) induction with 2 mg/kg propofol and nitrous oxide in 33% oxygen. As compared to propofol, significant cerebral tissue "hyperoxia" occurred with sevoflurane induction (p = 0.003). This did not resolve over time. As compared to intravenous induction with propofol, inhalational induction with "vasoparalytic" sevoflurane "hyperoxygenates" developing brains. This observation requires validation in larger trials to conclude appropriate effect on our practice of pediatric anesthesia and pediatric patient safety under anesthesia.