Changes in cortical electrical activity during induction of anaesthesia with thiopental/fentanyl and tracheal intubation: a quantitative electroencephalographic analysis.
BACKGROUND
There are regional differences in the effects of anaesthetics agents and perioperative stimuli on the EEG. We studied the topography of the EEG during induction of anaesthesia and intubation in patients receiving thiopental and fentanyl to document regional electrical brain activity.


METHODS
EEG was recorded in 25 patients in the awake state, after pre-medication, during induction, at loss of consciousness and after intubation. Eight bipolar recordings were made and the relative power of the frequency bands delta, theta, alpha, and beta were used (after z-score transformation for age) to measure changes in regional EEG activity.


RESULTS
Noxious stimulation during tracheal intubation partially reversed the slowing of the EEG caused by anaesthesia. During induction of anaesthesia alpha activity was most reduced in temporal and occipital regions. The most prominent EEG changes after intubation were an increase in alpha and a decrease in delta power (P<0.001). The largest changes were in the frontal and temporal leads for alpha and in the frontal and central leads for delta. Heart rate and arterial pressure remained constant during intubation.


CONCLUSIONS
Changes in alpha and delta power were identified as the most sensitive EEG measures of regional changes in electrical brain activity during anaesthesia and noxious stimulation.
Rundshagen
I
I
Department of Anaesthesiology, University Hospital Charité, Humboldt University of Berlin, Campus Charité Mitte, Berlin, Germany. ingrid.rundshagen@charite.de
Schröder
T
T
Prichep
L S
LS
John
E R
ER
Kox
W J
WJ
D000328:Adult; D000513:Alpha Rhythm / Q000187:drug effects; D000701:Analgesics, Opioid / Q000494:pharmacology; D000704:Analysis of Variance; D019162:Anesthetics, Combined / Q000494:pharmacology*; D018686:Anesthetics, Intravenous / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D001931:Brain Mapping / Q000379:methods; D003700:Delta Rhythm / Q000187:drug effects; D004569:Electroencephalography / Q000187:drug effects*; D005260:Female; D005283:Fentanyl / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007442:Intubation, Intratracheal / Q000379:methods*; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods; D013874:Thiopental / Q000494:pharmacology*
D000701:Analgesics, Opioid; D019162:Anesthetics, Combined; D018686:Anesthetics, Intravenous; D013874:Thiopental; D005283:Fentanyl