This case study describes the repair of total anomalous pulmonary venous connection (TAPVC) in a 50-day-old baby. TAPVC is a congenital heart defect where the pulmonary veins do not connect normally to the left atrium. The baby underwent surgery to reroute the pulmonary veins and close an atrial septal defect. In the postoperative period, the baby developed pulmonary arterial hypertension crisis, which was treated with reintubation, vasoactive drugs, and sildenafil infusion through a pulmonary artery catheter. The baby's condition gradually improved and was extubated again after 48 hours of ventilation support.