Significance: If in fact, BNP testing could be shown to improve the evaluation and management of patients with respiratory failure in the ICU, this would represent a major advance in the clinical care of seriously ill patients, and as well, highlight the potential for considerable cost-saving. Accordingly, if this study would have a positive result and in fact demonstrate that a BNP guided diagnostic strategy reduces total treatment time and total cost of treatment, it would be the first randomized controlled trial demonstrating that a new diagnostic test improves the evaluation and management of ICU patients. Given the enormous expenses associated with intensive care, such a study seems overdue.