AUTHOR=Sun Christophe , Longrois Dan , Holcman David 

TITLE=Spectral EEG correlations from the different phases of general anesthesia

JOURNAL=Frontiers in Medicine

VOLUME=Volume 10 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2023.1009434

DOI=10.3389/fmed.2023.1009434

ISSN=2296-858X

ABSTRACT=Electroencephalography (EEG) signals contain transient oscillation patterns commonly
used to classify brain states in responses to action, sleep, coma or anesthesia. Using a
time-frequency analysis of the EEG, we search for possible causal correlations between
the successive phases of general anesthesia. We hypothesize that it could be possible to
anticipate recovery patterns from the induction or maintenance phases. For that goal, we
track the maximum power of the α−band and follow its time course. We quantify the
frequency shift of the α−band during the recovery phase and the associated duration.
Using Pearson coefficient and Bayes factor, we report non-significant linear correlation
between the α−band emergence trajectory during recovery and the presence of the δ or
the α rhythms during the maintenance phase. We also found no correlations between the
α frequency and duration shifts and the total duration of the flat EEG epochs (iso-electric
suppressions) induced by a propofol bolus injected during induction. Finally, we quantify
the instability of the α−band using the mathematical total variation that measures pos-
sible deviations from a flat line. To conclude, the present correlative analysis shows that EEG dynamics extracted from the initial and maintenance phases of general anesthesia cannot anticipate both the emergence trajectory and the extubation time.