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 (EEG) requiring substantial human, technical, and financial resources. We here evaluate whether a simplified 4-frontal electrode montage (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 EEG montage, whose analysis was then compared to an expert's interpretation made on EEG recordings. The main outcome measure was the degree of correlation between EEG and EEG montages to identify EEG patterns of interest. The performance of the Synek scores calculated on EEG and EEG montage to predict outcomes (i.e., 28-day mortality and 90-day Rankin score [Formula: see text]) was investigated in a secondary exploratory analysis.

RESULTS

The detection of EEG patterns using EEG was statistically similar to that of EEG for background rhythm (Spearman rank test, ρ = 0.66, p < 0.001), discontinuity (Cohen's kappa, [Formula: see text] = 0.955), reactivity ([Formula: see text] = 0.739) and the Synek's score (ρ = 0.794, p < 0.001). Using the Synek classification, we found similar performances between EEG and EEG montages in predicting 28-day mortality (AUC EEG 0.71, AUC EEG 0.68) and for 90-day poor neurologic outcome (AUC EEG 0.71, AUC EEG 0.66). An exploratory analysis confirmed that the Synek scores determined by 4 or 21 electrodes were independently associated with 28-day mortality and poor 90-day functional outcome.

CONCLUSION

In adult patients under VA-ECMO, a simplified 4-frontal electrode EEG montage interpreted by an intensivist, detected common EEG patterns associated with poor outcomes, with a performance similar to that of a standard EEG montage interpreted by expert neurophysiologists. This simplified montage could be implemented as part of a multimodal evaluation for bedside prognostication.