Prognostic significance of EEG abnormalities in acute septic patients in ICU: A study about 110 patients

Abstract

Background It is known that sepsis is associated with increased mortality, delirium and long-term cognitive impairment in ICU patients. EEG abnormalities occurring at acute stage of sepsis may correlate with outcome. Predictive value of early standard EEG abnormalities for mortality in ICU septic patients remains to be assessed. Methods In this prospective, single center, observational study, standard EEG was performed, analyzed and classified according to both Synek and Young EEG scales, in consecutive patients acutely admitted in ICU for sepsis. Delirium, coma and the level of sedation were assessed at the time of EEG recording; and duration of sedation, occurrence of in-ICU delirium or death were assessed during follow-up. Adjusted analyses were carried out using multiple logistic regression. Results One hundred ten patients were included, mean age 63.8 ± 18.1 years, median Simplified Acute Physiology Score (SAPS-II): 38 (29–55). At the time of EEG recording, 46 patients (42%) were sedated and 22 (20%) suffered from delirium. Overall, 54 patients (49%) developed delirium, of which 32 (29%) in the days after EEG. Twenty-three (21%) patients died in the ICU. Absence of EEG reactivity was observed in 27 patients (25%), periodic epileptiform discharges (PEDs) in 21 (19%) and electrographic seizures (ESZ) in 17 (15%). ICU mortality was independently associated with absence of EEG reactivity (OR: 4.44; 95% CI [1.37–14.3], Synek Grade ≥ 3 (OR: 5.35; 95% CI [1.66–17.2]) and Young Grade ≥ 1 (OR: 3.44; 95% CI [1.09–10.8]), after adjustment to SAPS-II at admission and level of sedation. Delirium at the time of EEG was associated with ESZ in non-sedated patients (32% vs 10%, P = 0.037) and occurrence of delirium in the days after EEG was associated with absence of EEG reactivity (39% vs 10%, P = 0.003). Conclusions In this prospective cohort of 110 septic ICU patients, early standard EEG was significantly disturbed. Absence of EEG reactivity, Synek grade ≥ 3 and Young grade ≥ 1 at day 1 to 3 following admission were independent predictors of ICU mortality and associated with prevalence of delirium.