NPPB and persistent fetal circulation syndrome: This review details PPHN phenotypes, pathophysiology, etiology, diagnostics including echocardiography and biomarkers like B-type Natriuretic Peptide (BNP) or N-terminal pro-B-type Natriuretic Peptide (NT-proBNP), and current therapeutic modalities, from lung recruitment and surfactant to targeted vasodilator therapy (iNO, sildenafil, milrinone, bosentan) and extracorporeal membrane oxygenation (ECMO).