Supplementary Material for: Fetal-to-neonatal transition of an infant with Transposition of the Great Arteries and intact ventricular septum: a case report

Introduction: Transposition of the great arteries (TGA), especially with intact ventricular septum (TGA-IVS), presents unique challenges during fetal-to-neonatal transition, which can contribute to developing persistent pulmonary hypertension of the newborn (PPHN). Case presentation: A male newborn with TGA-IVS, delivered via caesarean section, presented with hypoxemia and tachycardia immediately after birth (preductal SpO2: 50-60%, postductal SpO2: 70-75%). Echocardiography revealed a floppy interatrial septum and two interatrial connections with bidirectional shunting. Ductal flow showed systolic right-to-left shunting, suggesting high pulmonary vascular resistance. Immediate post-birth management included non-invasive respiratory support with continuous positive airway pressure at 100% oxygen and administration of prostaglandin E2 to maintain ductal patency. Despite initial low oxygen saturation levels, escalation of intensive treatments was deferred based on continuous trend monitoring of vital signs and echocardiographic indicators. Oxygenation and circulation gradually improved within the first 2 hours after birth to normal values, obviating escalation of intensive interventions like intubation, nitric oxide and/or balloon atrial septostomy. Arterial switch operation at day 3 post-birth was successful. Conclusion: This case highlights the possible contribution of fetal-to-neonatal transition in TGA-IVS to developing PPHN, which may subside after transition. Moreover, the potential for providing a gentle hemodynamic transition without invariably needing early invasive interventions after birth.