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

Journal Article (Journal Article)

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) mumol/100 g min-1 vs 39 (8)mumol/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) mumol/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.

Full Text

Duke Authors

Cited Authors

  • Reasoner, DK; Warner, DS; Todd, MM; McAllister, A

Published Date

  • August 1990

Published In

Volume / Issue

  • 65 / 2

Start / End Page

  • 210 - 215

PubMed ID

  • 2223338

International Standard Serial Number (ISSN)

  • 0007-0912

Digital Object Identifier (DOI)

  • 10.1093/bja/65.2.210


  • eng

Conference Location

  • England