Clinical question Does B-type natriuretic peptide (BNP) testing in the emergency department improve outcomes or affect hospitalization rates?
Bottom line In contrast to results from an earlier study, testing the BNP levels of patients with severe dyspnea does not decrease rates of admission or length of stay. We now have conflicting evidence regarding whether routine BNP testing is warranted in the emergency department. (Level of evidence = 1b)
Synopsis These Australian researchers enrolled 612 patients presenting with severe shortness of breath, defined as requiring assessment by a physician within 30 minutes of arrival, at either of two emergency departments. The patients—with an average age of 74 years; 54% were men—were randomized, allocation concealment uncertain, to have BNP measured, or not, along with routine investigations. Emergency department physicians were instructed that a BNP level of less than 100 ng/mL made the diagnosis of heart failure unlikely, and a level of more than 500 ng/mL made heart failure likely. Heart failure, determined by two physicians masked to BNP results, was diagnosed in 45% of the enrolled patients, and almost all patients (85.1%) were admitted. Admission rates, length of stay, intensive care unit admissions, mortality within 30 days, and use of appropriate heart failure medication did not differ with the knowledge of patients' BNP levels. These results conflict with another study conducted in Switzerland (N Engl J Med. 2004; 350[7]:647-654) that found that BNP testing in the emergency department decreased hospitalizations from a similar 85% to 75%. This earlier study, though, used point-of-care BNP testing that produced results within 20 minutes, whereas the test used in this study required approximately 1 hour for processing.
Schneider HG, Lam L, Lokuge A, et al. B-type natriuretic testing, clinical outcomes, and health services use in emergency department patients with dyspnea. Ann Intern Med. 2009; 150(6):365-371.