title: Bispectral analysis of the electroencephalogram during induction of anesthesia may predict hemodynamic responses to laryngoscopy and intubation.
abstract: The use of electroencephalography as a measure of adequacy of anesthesia has achieved limited success. Our purpose was to determine whether the non-linear properties of the electroencephalogram (EEG) as defined by the bispectral index was a better predictor of autonomic responses to endotracheal intubation during opioid-based anesthesia than the linear statistical properties of the EEG formulated by power spectral analysis. Thirty-nine adults scheduled for elective non-cranial surgery had a continuous EEG recorded during induction of anesthesia and endotracheal intubation. Anesthesia consisted of thiopental and nitrous oxide in oxygen, followed by 1 of 5 randomized opioid dose regimens. The EEG was continuously recorded and blood pressure was measured every minute. All electroencephalographic parameters were derived for the 3 min before and after intubation and were compared to the blood pressure and heart rate responses. Responders were defined by 2 analyses: patients who had a 20% or greater increase (1) in blood pressure or (2) in heart rate to laryngoscopy. Responders and non-responders were compared using Student's unpaired t test, and differences due to dose regimens were examined with logistic regression. Based on the criterion for blood pressure change, there were 27 responders and 12 non-responders. Heart rate changes did not differentiate between the two groups. There was a significant difference between response groups as measured by the bispectral index which distinguished responders from non-responders independently of the amount of drug given. None of the variables of power spectral analysis accurately distinguished responder from non-responder.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Anesthesia and Neurology, Massachusetts General Hospital, Harvard Medical School, Boston 02114.
authors.forename: L A
authors.initials: LA
authors.lastname: Kearse
authors.forename: P
authors.initials: P
authors.lastname: Manberg
authors.forename: F
authors.initials: F
authors.lastname: DeBros
authors.forename: N
authors.initials: N
authors.lastname: Chamoun
authors.forename: V
authors.initials: V
authors.lastname: Sinai
mesh_terms: D000328:Adult; D000768:Anesthesia, General; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology*; D001921:Brain / Q000187:drug effects / Q000502:physiology*; D004569:Electroencephalography; D005260:Female; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D007442:Intubation, Intratracheal; D007828:Laryngoscopy; D008297:Male; D008875:Middle Aged; D012815:Signal Processing, Computer-Assisted