Seizures in Children with Cardiac Disease on Extracorporeal Membrane Oxygenation

Background Children supported with extracorporeal membrane oxygenation (ECMO) have been shown to be at risk for developing seizures. However, previous studies have consisted of heterogeneous patient populations. We aimed to describe the rate of seizures in pediatric patients receiving ECMO for cardiac indications and to identify risk factors for the occurrence of this complication. Methods This is a retrospective cohort study of consecutive pediatric patients on ECMO for congenital or acquired cardiac disease between 2014 and 2018 at a tertiary care pediatric hospital. Results We reviewed 110 children, of whom 104 (95%) received continuous electroencephalogram for at least 48 h after ECMO initiation. Seizures were observed in 20 (18%) children. Seizures were subclinical only in 13 (65%) patients, and 8 (40%) developed status epilepticus. The median time from ECMO initiation to first seizure was 34 h (25%, 75%: 19, 44). Children with seizures were more likely to have suffered pre-ECMO cardiac arrest (odds ratio 5.7, 95% confidence interval 2.0-16.1, p < 0.001), require extracorporeal cardiopulmonary resuscitation (odds ratio 5.2, 95% confidence interval 1.9-14.7, p < 0.001), and have been cannulated via the cervical vessels (p = 0.029). Children with seizures also had lower pH nadir prior to ECMO (p = 0.015) and had higher peak lactate prior to ECMO (p = 0.002). Patients with seizures had significantly a longer median intensive care unit length of stay, (43 versus 32 days, p = 0.02), had a significantly worse pediatric cerebral performance score (2 versus 1, p = 0.03), and tended to have worse survival to hospital discharge (50% versus 71%, p = 0.069). Conclusions Seizures in pediatric patients on ECMO for cardiac indications are common, occurring in nearly one in five patients. Seizures are frequently subclinical only and often progress to status epilepticus. Continuous electroencephalogram is therefore warranted for this patient population, especially in the setting of cardiac arrest, extracorporeal cardiopulmonary resuscitation, or severe metabolic acidosis.