Predictive value of short-term EEG recording in critically ill adult patients

We assessed the EEG patterns and their prognostic significance in critically ill adult patients with encephalopathy, by digital EEGs lasting up to 1 hour. Of the 110 patients (age: 43.8 ± 19.4 years, male: female:1.6:1) studied, 32% had hypoxic ischemic encephalopathy (HIE), 17% severe infections, and 14.5% stroke. Observed EEG patterns were diffuse slowing (41%), low-voltage cerebral activity (LVCA, 18%), nonconvulsive status epilepticus (NCSE, 13.6%), and periodic abnormalities (9.1%). LVCA, age, Glasgow Coma Score (GCS) <8, HIE, and modified Hockaday's EEG grades of IV and V were associated with poor outcome (p <0.005) at hospital discharge; generalized slowing was associated with a relatively good outcome (p = 0.003). On multivariate analysis, factors independently predictive of mortality were LVCA, older age, and poor GCS. In conclusion, LVCA and generalized background slowing were common EEG patterns among critically ill intensive care unit (ICU) patients with encephalopathy of varied etiologies. While LVCA was associated with a poor outcome, generalized background slowing predicted better prognosis. Conventional short-duration, bedside EEG studies could aid in the recognition of electrographic patterns of prognostic importance in facilities where continuous EEG monitoring is lacking.