Effects of nitrous oxide on cerebral metabolic rate in rats anaesthetized with isoflurane

D. K. Reasoner, D. S. Warner, M. M. Todd, A. Mcallister

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

It has been demonstrated in several species that a significant increase in cerebral blood flow (CBF) occurs when nitrous oxide is added to a volatile anaesthetic. This blood flow response could result from an increase in cerebral metabolic rate or from a direct effect of nitrous oxide on cerebral vessels. To investigate this, the cerebral metabolic rate for glucose (CMRglu) was determined autoradiographically in rats receiving isoflurane anaesthesia with or without nitrous oxide. An increase in anaesthetic depth from 0.5 to 1.0 MAC achieved with isoflurane alone caused a significant reduction in CMRglu (52 (SD11) μmol/100 gmin-1 vs 39 (8) μmol/100 g min-1). In contrast, the addition of 70% nitrous oxide (0.5 MAC) to 0.5 MAC isoflurane anaesthesia (1 MAC total) left CMRglu unchanged (54 (4) μmol/100 g min-1). We conclude that 70% nitrous oxide does not alter cerebral metabolic rate when administered with 0.5 MAC isoflurane. Because CBF increases substantially under very similar conditions, our data indicate that the CBF effects of nitrous oxide, when administered with a volatile agent, were direct and mediated by factors other than changes in cerebral metabolic rate.

Original languageEnglish (US)
Pages (from-to)210-215
Number of pages6
JournalBritish Journal of Anaesthesia
Volume65
Issue number2
DOIs
StatePublished - Aug 1990

Keywords

  • Anaesthetics gases: nitrous oxide
  • Anaesthetics volatile: isoflurane
  • Brain: cerebral metabolic rate

Fingerprint

Dive into the research topics of 'Effects of nitrous oxide on cerebral metabolic rate in rats anaesthetized with isoflurane'. Together they form a unique fingerprint.

Cite this