Electroencephalogram in the intensive care unit: a focused look at acute brain injury

Over the past decades, electroencephalography (EEG) has become a widely applied and highly sophisticated brain monitoring tool in a variety of intensive care unit (ICU) settings. The most common indication for EEG monitoring currently is the management of refractory status epilepticus. In addition, a number of studies have associated frequent seizures, including nonconvulsive status epilepticus (NCSE), with worsening secondary brain injury and with worse outcomes. With the widespread utilization of EEG (spot and continuous EEG), rhythmic and periodic patterns that do not fulfill strict seizure criteria have been identified, epidemiologically quantified, and linked to pathophysiological events across a wide spectrum of critical and acute illnesses, including acute brain injury. Increasingly, EEG is not just qualitatively described, but also quantitatively analyzed together with other modalities to generate innovative measurements with possible clinical relevance. In this review, we discuss the current knowledge and emerging applications of EEG in the ICU, including seizure detection, ischemia monitoring, detection of cortical spreading depolarizations, assessment of consciousness and prognostication. We also review some technical aspects and challenges of using EEG in the ICU including the logistics of setting up ICU EEG monitoring in resource-limited settings.

Automated summary

Electroencephalography (EEG) has become a widely used and highly sophisticated brain monitoring tool in intensive care unit (ICU) settings. The most common application is the management of refractory status epilepticus. Frequent seizures, including nonconvulsive status epilepticus (NCSE), are associated with worsening brain injury and outcomes. EEG has been used to identify and quantify rhythmic and periodic patterns that do not meet strict seizure criteria, and link them to pathophysiological events in critical and acute illnesses. EEG is increasingly analyzed quantitatively along with other modalities to generate innovative measurements with potential clinical relevance.