PERSISTENT PULMONARY HYPERTENSION OF THE NEWBORN

A. Background 1. Characterized by elevated pulmonary pressures after birth in conjunction with a right-to-left shunt across the ductus arteriosus or foramen ovale a. Previously called persistent fetal circulation b. Imbalance of relative excess of endogenous vasoconstrictors (e.g., endothelin-1, thromboxane A2) to endogenous vasodilators (e.g., nitric oxide, prostacyclin) c. Usually transient; may be idiopathic or secondary to an underlying disease d. Affects primarily term neonates 2. Causes of secondary pulmonary hypertension a. Congenital diaphragmatic hernia b. Meconium aspiration syndrome c. Pneumonia/sepsis

d. RDS e. BPD f. Congenital heart defects g. In utero drug exposure – Can occur after in utero exposure to nonsteroidal anti-inflammatory drugs or selective serotonin reuptake inhibitors