Indications, results and consequences of electroencephalography in neurocritical care: A retrospective study

Purpose: Electrocencephalography (EEG) is a tool to assess cerebral cortical activity. We investigated the indications and results of routine EEG recordings in neurocritical care patients and corresponding changes in antiseizure medication (ASM). Materials and methods: This was a single-center, retrospective cohort study. We included all adult Intensive Care Unit (ICU) patients with severe acute brain injury who received a routine EEG (30-60 min). Indications, background patterns, presence of rhythmic and periodic patterns, seizures, and adjustments in ASM were documented. Results: A total of 109 patients were included. The EEGs were performed primarily to investigate the presence of (non-convulsive) status epilepticus ((NC)SE) and/or seizures. A (slowed) continuous background pattern was present in 94%. Low voltage, burst-suppression and suppressed background patterns were found in six patients (5.5%). Seizures were diagnosed in two patients and (NC)SE was diagnosed in five patients (6.4%). Based on the EEG results, ASM was changed in 47 patients (43%). This encompassed discontinuation of ASM in 27 patients (24.8%) and initiation of ASM in 20 patients (18.3%). Conclusions: All EEGs were performed to investigate the presence of (NC)SE or seizures. A slowed, but continuous background pattern was found in nearly all patients and (NC)SE and seizures were rarely diagnosed. Adjustments in ASM were made in approximately half of the patients.