Abstracts

Rationale: Continuous EEG monitoring (cEEG) permits the detection of convulsive and nonconvulsive seizures among critically ill children admitted to the intensive care unit (ICU). Several retrospective studies have reported high rates of nonconvulsive seizures among critically adults and children undergoing clinical cEEG monitoring. Methods: Single-center retrospective review of clinical cEEG monitoring performed in our pediatric and neonatal ICUs between 2004 and 2009. We examined the indications for cEEG monitoring, the clinical characteristics of monitored patients, and the occurrence and timing of seizures. Results: 258 cEEG studies were performed over a 70-month period on 194 patients, of which 24% were neonates. Seizures had occurred in 27% of patients prior to cEEG monitoring, and 31% had a prior diagnosis of epilepsy. Indications for cEEG monitoring were either therapeutic: to guide treatment of seizures or status epilepticus (47%); or diagnostic: to characterize clinical events suspected to be seizures (24%), to evaluate an unexplained alteration in consciousness (23%), and to monitor for seizures in paralyzed patients (5%). Duration of cEEG monitoring varied from 4 hours to 8 days, but was most commonly 12-24 hours. Seizures were detected in 50% of cEEG recordings, and in 50% of patients monitored. Nonconvulsive seizures occurred in 32% of patients. Nonconvulsive seizures were far more common among cEEGs performed for diagnostic purposes (89%), than among cEEGs performed for therapeutic purposes (26%). All seizures in the diagnostic cEEG group were captured within 24 hours of monitoring. Conclusions: These findings confirm the diagnostic utility of continuous EEG monitoring among critically ill children. Nonconvulsive seizures are more common among critically ill children monitored for diagnostic purposes than those monitored for therapeutic purposes. 24 hours of cEEG monitoring appears sufficient to detect seizures. The impact of cEEG monitoring on seizure treatment and outcomes requires further study.