A measure of consciousness and memory during isoflurane administration: the coherent frequency.

R. Munglani*, J. Andrade, D. J. Sapsford, A. Baddeley, J. G. Jones

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The coherent frequency (CF) of the auditory evoked response (AER) is derived using auditory clicks presented at frequencies in the range 5-47 Hz. CF and psychological performance were measured while seven subjects breathed isoflurane in doses increasing from 0% to 0.2%, 0.4% and 0.8% end-tidal concentration and then decreasing to 0%. With increasing doses of isoflurane, CF decreased and there was a decrease in within-list recognition (WLR) and category recognition (CR) scores. There was a correlation between changes in CF and WLR (P < 0.05) and between CF and category recognition (CR) (P < 0.05). A painful stimulus given in conjunction with 0.4% isoflurane caused an increase in CF, WLR and CR in some subjects. This did not reach statistical significance for the group as a whole, apart from the short word interval scores in the WLR which indicated an increase in attention (P < 0.01). Subjects did not respond with 0.8% isoflurane, either before or after painful stimulation. Reduction of end-tidal isoflurane from 0.8% to 0% caused an increase in the CF and improved performance on the psychological tests. A category generation task on recovery showed no evidence of implicit learning of words presented in conjunction with 0.8% isoflurane.(ABSTRACT TRUNCATED AT 250 WORDS)
Original languageEnglish
Pages (from-to)633-641
Number of pages0
JournalBr J Anaesth
Volume71
Issue number5
DOIs
Publication statusPublished - Nov 1993

Keywords

  • Anesthesia
  • Inhalation
  • Awareness
  • Cognition
  • Consciousness
  • Evoked Potentials
  • Auditory
  • Female
  • Humans
  • Isoflurane
  • Male
  • Memory
  • Psychological Tests
  • Time Factors

Fingerprint

Dive into the research topics of 'A measure of consciousness and memory during isoflurane administration: the coherent frequency.'. Together they form a unique fingerprint.

Cite this