Use of Natriuretic Peptides in Critically Ill Patients: A Narrative Review

Background: Natriuretic peptides, including B-type natriuretic peptide (BNP) and N-terminal pro-B-type natriuretic peptide (NT-proBNP), are established biomarkers of myocardial stress and circulatory overload. Although originally validated for diagnosis and exclusion of heart failure, their diagnostic and prognostic applications have expanded significantly in the context of critical illness. However, interpretation in critically ill patients is complicated by confounding factors such as systemic inflammation and renal dysfunction. Objective: This review synthesizes current evidence on the diagnostic, monitoring, and prognostic applications of natriuretic peptides in critically ill adults. It further outlines practical considerations, confounding variables, and emerging complementary biomarkers pertinent to clinical decision-making. Methods: A structured search of PubMed, Embase, and the Cochrane Library (January 2000 to October 2025) identified studies evaluating BNP, NT-proBNP, and atrial natriuretic peptide (ANP) in intensive care unit (ICU) patients. Eligible studies and review articles assessed diagnostic utility, volume status, hemodynamic monitoring, and prognostic performance. Narrative synthesis was employed using information obtained from eligible studies. Results: Twenty-four studies met the inclusion criteria. BNP and NT-proBNP facilitate differentiation between cardiogenic and noncardiogenic respiratory failure, identification of mixed shock states, and assessment of volume status when used in association with other modalities such as echocardiography and ultrasonography. Elevated natriuretic peptide concentrations consistently predict mortality, acute kidney injury, prolonged mechanical ventilation, and adverse outcomes in several disease states, including sepsis, acute respiratory distress syndrome [ARDS], postoperative cardiac dysfunction, and COVID-19-related critical illness. However, interpretation remains limited by confounders, including renal impairment, age, systemic inflammation, brain injury, mechanical ventilation, and right-ventricular strain/dysfunction. Conclusions: Natriuretic peptides serve as valuable adjuncts for diagnostic assessment, hemodynamic monitoring, and risk stratification in the ICU. When interpreted with attention to biological kinetics and clinical context, these biomarkers enhance multimodal monitoring and support individualized management. Future research should refine ICU-specific cutoffs and assess natriuretic peptide-guided therapeutic strategies in prospective multicenter trials.