Early BNP Measurement Yields More Efficient ED Care

Abstract & Commentary

Source: Mueller C, et al. Use of B-type natriuretic peptide in the evaluation and management of acute dyspnea. N Engl J Med 2004;350:647-654.

This randomized, controlled, single-blinded study examined the hypothesis that rapid measurement of B-type natriuretic peptide levels (BNP) would improve the care of patients presenting to the emergency department (ED) with acute dyspnea. Consecutive patients complaining of breathlessness were enrolled in the study, provided they did not have severe renal dysfunction, shock, or trauma. All patients underwent routine evaluation at the treating physicians’ discretion. Patients randomized to the BNP group underwent BNP measurement using a rapid assay, and the results were disclosed to the treating physicians. Heart failure was considered unlikely with BNP values less than 100 pg/mL and highly likely with BNP values greater than 500 pg/mL. Clinical judgment and further testing were advised for patients with intermediate BNP values. The authors compared time to discharge, cost of treatment, and mortality between patients in the BNP measurement group and those not undergoing BNP assessment (controls).

Four hundred fifty-two patients were enrolled, evenly split and evenly matched between the BNP group and the control group. The mean age of subjects was 70 years; half had a history of coronary artery disease, and half had a history of pulmonary disease. Time from ED presentation to final disposition was 63 minutes in the BNP group and 90 minutes in the control group. Fewer patients in the BNP group required admission (75% vs 85%) and fewer required intensive care (15% vs 24%). Among patients requiring admission, those in the BNP group had a shorter median length of stay (8 vs 11 days) and lower hospitalization costs. All these differences were statistically significant. While final diagnosis was heart failure in about half of the patients in each group, exacerbation of chronic obstructive pulmonary disease was diagnosed more often in the BNP group than in the control group (23% vs 11%). Mortality rates were similar in the two groups.

Commentary by David J. Karras, MD, FAAEM, FACEP

BNP is secreted by ventricular myocytes in response to stretch. BNP appears to be a highly useful marker of congestive heart failure and an excellent adjunct to clinical diagnosis in patients presenting to the ED with acute dyspnea. BNP elevation is associated with the presence of heart failure, the severity of heart failure, and patient prognosis.1 An earlier study found BNP to be a stronger predictor of heart failure in ED patients than any historical, physical, or radiographic finding.2 BNP has also been shown to be useful in detecting unsuspected heart failure in patients with pulmonary disease.2

This study adds to the growing body of literature supporting early BNP assessment in ED patients with dyspnea. While BNP measurement is not a gold standard, this study suggests that incorporating BNP into the work-up of ED patients with dyspnea facilitates confirmation of heart failure or the rendering of an alternative diagnosis (e.g., exacerbation of chronic obstructive pulmonary disease), leading to more efficient evaluations, lower admission rates, and shorter hospital stays.

Dr. Karras, Associate Professor of Emergency Medicine, Department of Emergency Medicine Temple University School of Medicine, Director of Emergency Medicine Research, Temple University Hospital, Philadelphia, PA, is on the Editorial Board of Emergency Medicine Alert.

References

1. Harrison A, et al. B-type natriuretic peptide predicts future events in patients presenting to the ED with dyspnea. Ann Emerg Med 2002;39:131-138.

2. McCullough P. Uncovering heart failure in patients with a history of pulmonary disease: Rationale for the early use of B-type natriuretic peptide in the emergency department. Acad Emerg Med 2003;10: 275-277.

3. Maisel AS, et al. Rapid measurement of B-type natriuretic peptide in the emergency diagnosis of heart failure. N Engl J Med 2002;347:161-167.