P33-T Visual vs. automatic cEEG signal analysis in patients with delirium

Delirium is a disturbance of consciousness characterized by acute onset and fluctuating course of attention and cognition and it is associated with cognitive decline. The objective of this project was to explore whether continuous recording of EEG (cEEG) was useful to identify delirium in septic patients. Accordingly, we examined the hypothesis that cEEG distinguished between septic patients with and without delirium. Prospective, single center, observational study. A total of 102 patients admitted to the ICU between 2013 and 2015 with sepsis, without known neurologic injury underwent cEEG. Median cEEG time per patient was 44 h. Delirium screening was applied six times daily using the Confusion Assessment Method for the ICU (CAM-ICU). Sedation levels were assessed with the Richmond Agitation Sedation Scale (RASS). EEG reactivity tests (eye opening/closing) were applied three times daily in all patients. Data were described according to ACNS terminology and selected blocks underwent automated power spectral analysis and detrending. The quantitative analysis, showed that frequencies in the delta (0–3 Hz) and theta range (4–7 Hz) accompanied delirium. cEEG activity in the alpha (8–12 Hz) and beta (13–30 Hz) range were clearly present in septic patients without delirium and absent in septic patients with delirium. Results of automatic signal analysis correlated with our previous visual assessment. EEG activity in the high-frequency range reflects information processing and correlates to cognitive function. cEEG may be useful for differentiating between septic patients with and without delirium.