Extracorporeal membrane oxygenation (ECMO) is associated with a high risk of neurologic injury in pediatric patients, and early detection of injury is often challenging because the clinical examination is frequently limited by illness, medication, and developmental factors. Quantitative electroencephalography (qEEG), derived from standard continuous electroencephalography (cEEG), offers a bedside, continuous, and objective approach to neuromonitoring. We present a case series of two pediatric patients supported on ECMO who underwent cEEG monitoring within 6 hours of cannulation. Quantitative electroencephalography metrics, including global suppression percentage (SP) and total power (TP), were analyzed in relation to clinically significant neurologic events. In both cases, acute neurologic insults, including cardiac arrest, cerebral infarction, and intracranial hemorrhage, were associated with marked increases in global SP and concurrent decreases in TP. These findings highlight an inverse relationship between SP and TP across different mechanisms of brain injury and support further investigation of qEEG as a real-time physiologic marker of cortical suppression during acute neurologic deterioration.