Abstracts

Rationale: The main goal of this study is to describe the clinical and electroencephalographic (EEG) characteristics of children who underwent continuous EEG (cEEG) monitoring in the intensive care unit (ICU). Methods: This is a retrospective descriptive study of patients aged 1 month to 21 years who underwent cEEG (>3 hours) in the ICUs at Boston Children's Hospital in the period of 2011-2013. Patients were excluded if the cEEG was performed as part of an elective admission or if monitoring occurred in the setting of epilepsy surgery evaluations. In patients with multiple episodes of cEEG, only the first trial was considered. Results: 414 patients with a median age of 4.2 years were included. Of the 185 patients (45%) with a prior neurologic disorder, 79.5% (147 patients) had epilepsy. Neuroimaging was performed in 95% of patients and MRI was the most common imaging modality (Table 1). Clinical suspicion of convulsive seizures/characterization of events was the main indication for cEEG (83.6%), while encephalopathy/concern for nonconvulsive seizures (15.2%) was the second most common indication (Table 2). The etiology of the episode leading to cEEG monitoring was structural in 218 (52.7%) patients. A burst suppression pattern was seen in 4.4% of patients while 14.3 % of patients had a normal awake and asleep background. Overall, 96 (23.2%) patients had electrographic seizures, of which 21 (21.9%) were solely electrographic, 44 (45.8%) always had a clinical correlate, and the remainder had seizures with and without clinical correlate. 11 out of 96 (11.5%) of patients met criteria for status epilepticus, defined as a continuous seizure lasting >30 minutes in 6 patients or recurrent seizures totaling >50% of a one hour epoch in 5 patients. Overall, mortality was 14.3% (59 patients). In a model with death as the outcome and electrographic status epilepticus (ESE), structural lesion, prior diagnosis of epilepsy, prior developmental delay, and prior neurologic disorder as the predictors, the odds of death increased with the presence of prior diagnosis of epilepsy [OR 2.49 (95% C.I. 1.18-5.27) p=0.017]. Conclusions: We describe a large series of pediatric patients in the ICU who underwent cEEG monitoring. Twenty-three percent of patients had recorded seizures. Solely electrographic seizures are very common, affecting one-fifth of children with recorded seizures.