Abstract P186: Reduced Variability in Electroencephalographic Spatial Synchrony Patterns During Therapeutic Hypothermia Following Pediatric Cardiac Arrest is Associated with Unfavorable Short-Term Neurological Outcome
Early prognostication of injury severity following pediatric cardiac arrest (CA) is challenging. While some severely abnormal electroencephalographic (EEG) patterns are prognostic of poor outcome, the implications of polymorphic delta slowing and attenuation are unclear. Fewer fluctuations in synchronization derived from EEG signals are associated with unfavorable outcome in pediatric traumatic brain injury. Variability in EEG spatial synchrony has not been evaluated in children following CA. We hypothesized that following successful resuscitation from CA, children with worse short-term neurological outcome would have lower variability in spatial synchrony patterns than children with favorable outcome. With IRB approval, we retrospectively evaluated the spatial complexity of the synchrony pattern of a convenience sample of 12 patients’ EEGs. All patients received standardized therapeutic hypothermia and EEGs. By conventional EEG reading, all patients demonstrated delta slowing and attenuation (<10 microvolts), without any organization or admixed faster frequencies. Patients with burst suppression were excluded. The first artifact-free 30 second epoch of EEG was processed to calculate spatial complexity at 3, 6 and 15 Hz at each electrode and averaged across all electrodes for each patient. For each Hz grouping, outcome groups were compared for mean and individual electrode spatial complexity by T-test. Favorable neurologic outcome was defined as no change from the pre-arrest Pediatric Cerebral Performance Category (PCPC) or discharge PCPC of 1, 2, or 3. Age at arrest was 12 [7, 26] months. CPR duration was 5 [3, 18] minutes. Outcome was favorable in 6 and unfavorable in 6 patients. Time from arrest to initial EEG epoch was 8 [6, 9] hours. At 3 Hz (delta frequency), patients with an unfavorable outcome had a lower mean spatial complexity (0.1781 vs. 0.1894, p=0.012). For individual electrodes, patients with unfavorable outcome had significantly lower spatial complexity in frontal electrodes. In children with unfavorable neurologic outcome following therapeutic hypothermia after CA, EEG spatial complexity, especially in the frontal regions, is lower than in children with favorable neurologic outcome.