Natriuretic Peptides (BNP, NT-proBNP) Aid Critical Illness Diagnosis and Prognosis Despite Confounding Factors

Critical illness often presents with complex, overlapping symptoms, making accurate diagnosis and prognosis challenging in the intensive care unit (ICU). Traditional diagnostic tools can be insufficient or invasive, leading to delays in targeted therapy. Natriuretic peptides (NPs), such as B-type natriuretic peptide (BNP) and N-terminal pro-B-type natriuretic peptide (NT-proBNP), are established biomarkers of myocardial stress and circulatory overload, primarily used in heart failure (HF). However, their utility in the heterogeneous environment of critical illness is complicated by factors like systemic inflammation and renal dysfunction, necessitating a clearer understanding of their application. This review addresses the gap in synthesizing their expanded roles and interpretive nuances in this complex patient population.

This narrative review synthesized current evidence on the diagnostic, monitoring, and prognostic applications of natriuretic peptides in critically ill adults. Researchers conducted a structured search across PubMed, Embase, and the Cochrane Library, identifying studies published from January 2000 to October 2025. The search focused on studies evaluating BNP, NT-proBNP, and atrial natriuretic peptide (ANP) in ICU patients. Eligible studies and review articles assessed diagnostic utility, volume status, hemodynamic monitoring, and prognostic performance. A narrative synthesis approach was employed to integrate information from the 24 studies that met the inclusion criteria, focusing on practical considerations and confounding variables.

The review of 24 studies consistently demonstrated the utility of BNP and NT-proBNP in critically ill patients. These biomarkers facilitate the differentiation between cardiogenic and noncardiogenic respiratory failure, aiding in precise diagnosis. They are also instrumental in identifying mixed shock states and assessing volume status, particularly when integrated with other modalities like echocardiography and ultrasonography. > Elevated natriuretic peptide concentrations consistently predict adverse outcomes, including mortality, acute kidney injury, and prolonged mechanical ventilation across various critical illness states. Specifically, high NP levels were prognostic indicators in conditions such as sepsis, acute respiratory distress syndrome (ARDS), postoperative cardiac dysfunction, and COVID-19-related critical illness. While their predictive power is robust, the review highlighted that interpretation remains limited by confounders, including renal impairment and systemic inflammation, which can independently elevate NP levels. Despite these challenges, their consistent association with adverse outcomes underscores their value as prognostic tools.