The neurological application of long-term electroencephalography (EEG) monitoring in the intensive care unit (ICU) has been implemented in many healthcare institutions. The use of EEG as a monitoring tool in the ICU affords many potential benefits. Uses include the identification of seizures, vasospasm following subarachnoid hemorrhage (SAH), the assessment of coma and the determination of brain death. Neurologic critical care is focused on recognition and treatment of secondary insults. Often treatment is withheld because these insults are not recognized early enough until an irreversible deficit manifest. Continuous EEG (cEEG) monitoring provides a unique potential to recognize these insults and offers an opportunity for early intervention. Why should we continuously monitor the brain with EEG in the ICU? Nonconvulsive seizures (NCS) are common in comatose patients. Nonconvulsive Status Epilepticus (NCSE) and NCS 1 are damaging to brain tissue; thus, rapid control of seizures is essential to preserving brain function. With the increased use of cEEG in critical care areas, the purpose of this paper is to examine the use and benefits of EEG monitoring of ICU patients, review the indications for the use of cEEG and discuss technical issues and concerns when performing cEEG monitoring. This article has been divided into six distinct sections: (1) Seizures, NCS, and NCSE (2) Periodic Discharges 2 and Patterns on the Ictal-interictal Continuum, (3) Cerebral Ischemia, SAH, and Delayed Cerebral Ischemia (DCI), (4) Encephalopathy and Coma (5) ECI and Brain Death, and (6) ICU-cEEG Monitoring Techniques.
Keywords: Delayed cerebral ischemia; EEG ICU monitoring; neuro-critical care; nonconvulsive seizures; vasospasm.