Perfusion Index, N-Terminal Pro-B-Type Natriuretic Peptide, Oxygenation Index, and Delta-Oxygen Saturation as the Components of a Composite Bedside Severity Score for Echocardiographic Risk Stratification in Persistent Pulmonary Hypertension of the Newborn: A Prospective, Observational Study

A BSTRACT Background: Persistent pulmonary hypertension of the newborn (PPHN) carries significant morbidity and mortality, yet objective bedside severity stratification remains elusive where echocardiography is not immediately accessible. While individual markers, including oxygenation index (OI), N-terminal pro-B-type natriuretic peptide (NT-proBNP), and preductal-to-postductal oxygen saturation (SpO 2 ) difference, have been evaluated in isolation, no composite bedside score prospectively derived to integrate the perfusion index (PI) alongside these markers currently exists for early PPHN severity classification.