Which test provides confirmatory diagnostic evidence of PPHN?

• A. Differential oximeter readings
• B. Radiographic imaging
• C. Cardiac catheterization
• D. Echocardiogram with Doppler studies

Answer: (D)

Persistent pulmonary hypertension of the newborn (PPHN) is confirmed most effectively with echocardiography using Doppler. This test directly images the heart, estimates pulmonary artery pressures, and shows how blood is flowing through the heart and great vessels. In PPHN, you commonly see elevated right-sided pressures, right-to-left or bidirectional shunting across the ductus arteriosus and/or foramen ovale, and signs of the right ventricle working harder or the septum bowing into the left ventricle. Doppler adds the ability to estimate pressures and assess flow patterns, making the diagnosis concrete without invasive procedures.

Other tests can hint at abnormal oxygenation or structural concerns—differential pulse oximetry can suggest shunting, radiographs may show non-specific lung findings, and cardiac catheterization can measure pressures but is invasive and not used for routine confirmation. Echo with Doppler provides the strongest, noninvasive confirmatory evidence for PPHN.