Continuous EEG Monitoring for Status Epilepticus

Abstract

There has been a substantial increase in the use of continuous electroencephalography (C-EEG) in critically ill patients, most commonly for detection of nonconvulsive seizures. Studies have found that not only patients with primary brain insults but also those with systemic illness are at high risk of developing nonconvulsive status epilepticus (NCSE). The Neurocrit Care Society and The American Clinical Neurophysiology Society have published consensus statements or guidelines on the indications, duration, and technical aspects of EEG monitoring for status epilepticus (SE). Unified criteria for defining NCSE have also been proposed and published. Nevertheless, critically ill patients can have equivocal patterns, not clearly ictal (“ictal” is used to mean an electrographic seizure pattern in this chapter) or interictal, and have been considered to lie on an ictal-interictal continuum. Diagnostic treatment trials with IV benzodiazepines and non-sedating anti-seizure drugs (ASDs) can be helpful to determine if equivocal patterns are contributing to the patient’s impaired mental status or other neurologic deficits. The labor-intensive and time-consuming process of reviewing 24 h of EEG on many patients can be expedited by using tools such as quantitative EEG (Q-EEG) via commercial software packages. Thus far, there is some evidence to suggest that after strokes and head trauma, NCSE may worsen outcomes. Whether C-EEG monitoring and aggressive treatment of these seizures translates into improved patient outcomes is yet to be proven.