Dissociating the effects of nitrous oxide on brain electrical activity using fixed order time series modeling

  • Authors:

  • David T. J. Liley;Kate Leslie;Nicholas C. Sinclair;Martin Feckie

  • Affiliations:

  • Brain Sciences Institute, Swinburne University of Technology, Hawthorn, VIC 3122, Australia and Department of Pharmacology, University of Melbourne, VIC 3050, Australia;Department of Anaesthesia and Pain Management, Royal Melbourne Hospital, VIC 3050, Australia and Department of Pharmacology, University of Melbourne, VIC 3050, Australia;Cortical Dynamics Pty. Ltd., 1 Dalmore Drive, Scoresby, VIC 3179, Australia;Department of Anaesthesia and Pain Management, Royal Melbourne Hospital, VIC 3050, Australia

  • Venue:
  • Computers in Biology and Medicine
  • Year:
  • 2008

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Abstract

A number of commonly used anesthetics, including nitrous oxide (N"2O), are poorly detected by current electroencephalography (EEG)-based measures of anesthetic depth such as the bispectral index. Based on a previously elaborated theory of electrocortical rhythmogenesis we developed a physiologically inspired method of EEG analysis that was hypothesized to be more sensitive in detecting and characterizing N"2O effect than the bispectral index, through its combined EEG estimates of cortical input and cortical state. By evaluating sevoflurane-induced loss of consciousness in the presence of low brain concentrations of N"2O in 38 elective surgical patients, N"2O was associated with a statistically significant reduction in the input the frontal cortex received from other cortical and subcortical areas. In contrast the bispectral index responded only to low, but not to high, concentrations of N"2O.