A premature infant is suspected of having persistent pulmonary hypertension of the newborn. How is this diagnosis confirmed?

a. Arterial blood gas analysis
b. Chest radiography
c. Pulmonary angiography
d. Echocardiography
e. Cardiac catheterization

D
The diagnosis of PPHN should always be suspected in any infant with nonresponsive or ongoing hypoxemia and cyanosis that is out of proportion to the degree of pulmonary disease, oxygen requirement, and mean airway pressure support. The diagnosis of PPHN is confirmed by echocardiography. When PPHN is present, echocardiography demonstrates normal structural cardiac anatomy with evidence of pulmonary hypertension (e.g., flattened or displaced ventricular septum). Doppler studies show right-to-left shunting through the patent ductus arteriosus and/or foramen ovale.