NPPB and hydrops fetalis: This systematic review evaluates the diagnostic and prognostic utility of N-terminal pro-B-type natriuretic peptide (NT-proBNP), cardiac troponins, and D-dimer in acute cardio-respiratory syndromes, including heart failure (HF), acute coronary syndrome (ACS), pulmonary embolism (PE), acute respiratory distress syndrome (ARDS), and coronavirus disease 2019 (COVID-19)-related complications.