Abstracts from the Pediatric Critical Care Colloquium New York, NY November 11–13, 2016

Abstract

Introduction: Pulmonary artery thrombosis in preterm neonates is a rare and potentially life-threatening diagnosis. The treatment of pulmonary embolism in preterm neonates with systemic anticoagulation and thrombolytic therapy is controversial given the high risk for intracranial hemorrhage. Here we report a preterm infant who presented with an obstructive right pulmonary artery thrombus that was successfully treated with systemic heparin followed by tissue plasminogen activator (tPA). Report: A 13-day-old, former 34-week gestation twin male infant with an uncomplicated pre- and perinatal course was found cyanotic and limp at home 30 minutes after feeding. He was intubated upon presentation to the emergency room for hypercarbic and hypoxemic respiratory failure, and started on prostaglandin and dopamine infusions. Initial echocardiogram showed a structurally normal heart, with significant right to left shunting through a PFO, severe right ventricular dysfunction, and flattened interventricular septum suggestive of pulmonary hypertension. Despite inhaled nitric oxide, no improvement was seen in arterial oxygenation. Repeat echocardiogram revealed no flow through the right pulmonary artery (RPA) and subsequent CT angiography of the chest showed an occlusive pulmonary embolism in the right main pulmonary artery extending into lobar branches with additional emboli in the left interlobar artery. Cranial ultrasound showed no intracranial hemorrhage and heparin drip was initiated at 28 units/kg/hr following an initial bolus of 75 units/kg per institutional protocol. The patient was transferred to an affiliated PICU for possible thrombectomy. In light of the risks associated with surgical thrombectomy on cardiopulmonary bypass in this age group; the decision was made to start systemic tPA. Heparin infusion was decreased to 10 units/kg/hr and systemic tPA was started, initially at 0.06 mg/kg/hr to a maximum of 0.1 mg/kg/hr. Oxygenation improved significantly and reinstitution of flow through the RPA was seen on echocardiogram. TPA was reduced to 0.03 mg/kg/hr and discontinued after a total of 46 hours. Heparin was transitioned to subcutaneous enoxaparin. Follow-up CT angiogram demonstrated resolution of all previous pulmonary emboli and the patient was successfully extubated after discontinuation of tPA. Serial head ultrasounds showed no intracranial hemorrhage. Conclusion: Diagnosis of neonatal pulmonary artery thrombosis causing acute right ventricular dysfunction is rare and requires a high index of suspicion. Despite the risk of intracranial hemorrhage in the preterm neonate, our case suggests systemic anticoagulation and low-level thrombolytic therapy with serial imaging may be a valid therapy for preterm neonates with pulmonary embolism.