B-type natriuretic peptide (BNP), a 32-amino-acid polypeptide, is released predominately by the left and right cardiac ventricles and regulates a wide array of physiologic effects including natriuresis, diuresis, and vasodilatation. The main stimulus for the secretion of BNP is cardiac stress reflected by myocardial stretch and pressure or volume overload. Additionally, BNP levels are significantly elevated in pulmonary arterial hypertension (PAH) and seem to correlate strongly with hemodynamic changes, functional impairment, and cardiac stress in PAH. Proinflammatory cytokines, the activation of the sympathetic nervous system, and hypoxia have also been identified as additional triggers inducing BNP secretion.

Consequently, BNP levels may accurately reflect the presence and reveal the severity of the most prominent prognostic factors in AECOPD. We therefore aimed to evaluate the use of BNP to predict short-term and long-term outcomes in patients with AECOPD.

Materials and Methods

Setting and Study Population

This study specifically investigated the potential of plasma BNP levels to predict the need for ICU treatment as well as short-term and long-term mortality rates in patients with AECOPD recruited in the Procalcitonin Guidance of Antibiotic Therapy in Chronic Obstructive Lung Disease study, a prospective, randomized, open interventional trial conducted in the emergency department of the University Hospital Basel, Switzerland, from November 2003 through March 2005. The study was performed according to the principles of the Declaration of Helsinki and was approved by our local ethics committee. Written informed consent was obtained from ah participating patients.

In total, 208 consecutive patients > 40 years of age with an AECOPD were enrolled in the study. Patients were evaluated in the emergency department by at least two physicians: a resident in internal medicine, and a board-certified internal medicine in Canadian online Pharmacy specialist. The diagnosis of COPD was based on clinical history, physical examination, and spirometric criteria according to Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines.