Abstracts

Rationale: Electrographic seizures are common in critically ill children admitted to the Pediatric Intensive Care Unit (PICU). While predictors of outcome have been described in this patient population, the timeliness of EEG monitoring and subsequent early seizure detection has not been evaluated in the previous literature. The aim of this study is to describe factors associated with short-term mortality in children undergoing continuous EEG (cEEG) in the ICU.Methods: Retrospective observational study of pediatric patients from 28 days post-term to 21 years of age who underwent cEEG (defined as greater than 3 hours of uninterrupted EEG) in the PICU at Boston Children’s Hospital from 2011 to 2013. Patients were excluded if the cEEG was performed in the setting of an elective admission or if monitoring occurred in the setting of an epilepsy surgery evaluation. In patients with multiple episodes on cEEG in the ICU, only the first recording was considered. The main outcome measure in this study was in-hospital mortality. For the purposes of this study, we considered electrographic seizures (ES) as any seizure detected on cEEG including electro-clinical and electrographic-only seizures. Electrographic status epilepticus (ESE) was defined as a single seizure lasting greater than 30 minutes or multiple seizures totaling greater than 50 % of a 1 hour epoch.Results: We enrolled 414 pediatric patients (53.9%) with a median (p25-p75) age of 4.17 (0.8-11.3) years. Etiology was structural symptomatic in 213 (51.5%) children, non-structural symptomatic in 117 (28.3%), unknown in 6 (1.5%), and a non-central nervous system cause was identified in 78 (18.8%). The median (p25-p75) time from ICU admission to cEEG initiation was 17.8 (5.1-91.4) hours. Electrographic seizures occurred in 102 (24.6%) patients. Electrographic status epilepticus (SE) occurred in 12 (11.8%) patients. On univariate analysis, the absence of electrographic seizures (p=0.014), presence of electrographic SE (p=0.034), and time from ICU admission to cEEG (p=0.002) were associated with an increased mortality while age, gender, etiology, and time from ICU admission to first detected seizure were not (Table 1). After controlling for gender and age, the factors associated with mortality were the absence of seizures OR=0.23 (95% CI: 0.08-0.67), p=0.007, the presence of SE OR= 7.76 (95% CI: 1.47-40.91), p=0.016, and the time from ICU admission to initiation of cEEG OR= 1.001 (95% CI: 1.0002-1.001), p=0.005 (Table 2).Conclusions: Seizure burden (presence of electrographic SE) and time from ICU admission to the start of cEEG were independent predictors of mortality in pediatric patients undergoing cEEG in the ICU.