Simplified frontal EEG in adults under veno-arterial extracorporeal membrane oxygenation

Background EEG-based prognostication studies in intensive care units often rely on a standard 21-electrode montage ( std EEG) requiring substantial human, technical, and financial resources. We here evaluate whether a simplified 4-frontal electrode montage ( 4-front EEG) can detect EEG patterns associated with poor outcomes in adult patients under veno-arterial extracorporeal membrane oxygenation (VA-ECMO). Methods We conducted a reanalysis of EEG data from a prospective cohort on 118 adult patients under VA-ECMO, in whom EEG was performed on admission to intensive care. EEG patterns of interest included background rhythm, discontinuity, reactivity, and the Synek’s score. They were all reassessed by an intensivist on a 4-front EEG montage, whose analysis was then compared to an expert’s interpretation made on std EEG recordings. The main outcome measure was the degree of correlation between 4-front EEG and std EEG montages to identify EEG patterns of interest. The performance of the Synek scores calculated on 4-front EEG and std EEG montage to predict outcomes (i.e., 28-day mortality and 90-day Rankin score ≥ 4 ) was investigated in a secondary exploratory analysis. Results The detection of EEG patterns using 4-front EEG was statistically similar to that of std EEG for background rhythm (Spearman rank test, ρ = 0.66, p