Evaluation of “point of care” brain natriuretic peptide level in differentiating between cardiogenic and noncardiogenic acute dyspnea (a hospital-based study)

Introduction: Acute dyspnea is one of the most common reasons for admission to emergency rooms. It could be due to potentially life-threatening cardiac or respiratory conditions. Differentiation among these three disorders is frequently needed. In the condition of heart failure, where there is clinical need for early and appropriate treatment but no objective method for rapid diagnosis, the potential benefits are enormous for any biomarker that can reliably rule in or rule out this syndrome. Objectives: The objectives of this study are as follows: (i) To evaluate the role of point of care of brain natriuretic peptide (BNP) in acute dyspnea and (ii) To determine the cutoff level of BNP to differentiate between cardiogenic and noncardiogenic causes of dyspnea. Materials and Methods: This was an in-hospital cross-sectional study conducted at a tertiary care center. Patients were evaluated using predetermined performa. All these patients were subjected to routine blood investigations, digital chest X-ray, and 12-lead electrocardiography. At the same time point of care, BNP was done in each patient after obtaining informed written consent. All patients with BNP >100 or clinical suspicion for heart failure underwent two-dimensional echocardiography (ECHO) with color Doppler. Results: A cross-sectional study was conducted on 238 patients presenting with acute dyspnea. Almost all patients with BNP level >415 pg/ml had <45% ejection fraction, but patients with BNP level <415 pg/ml had echocardiographic findings not suggestive of heart failure. Conclusion: This study gives us a reliable cutoff level of 415 pg/ml of BNP which clearly distinguishes between cardiogenic versus noncardiogenic dyspnea.