Pulmonary Embolism in a Critically Ill Infant with Univentricular Parallel Circulation

A 3-month-old infant patient with hypoplastic left heart syndrome diagnosed in the prenatal period required long-term intensive care for refractory chylothorax and chylous ascites after undergoing bilateral pulmonary artery banding at age 6 days. Weaning from mechanical ventilation was difficult due to massive edema, and a central venous catheter was required because enteral feeding was hampered by the refractory chyle leakage, for which surgery was ineffective. On the evening after central venous catheter replacement was performed, his respiratory condition suddenly deteriorated; cardiac ultrasound revealed that the left pulmonary arterial blood flow had decreased, and enhanced computed tomography demonstrated a left pulmonary embolism (PE), which was identified as the cause of a sudden decrease in the pulmonary blood flow. The patient died due to refractory septic shock at age 5 months. PEs in children, especially patients with cyanotic congenital heart disease, are difficult to diagnose because of their atypical presentation. Current diagnostic criteria are based on adult guidelines, and a few factors in the criteria, such as tachycardia and hypoxia, are difficult to apply for pediatric cyanotic patients with intracardiac or extracardiac right-to-left shunt. In fact, those criteria have lower specificities in children. In conclusion, the present case suggested that a sudden decrease in the pulmonary blood flow can aid the physicians in diagnosing PE in patients with cyanotic congenital heart disease. We need more pediatric cases and evidence of PE in children to make a PE guideline, which is specific to pediatric patients including cyanotic congenital heart disease.