The measurement of serum BNP levels is advocated in the acute evaluation of patients with dyspnea as an aid leading to the diagnosis of congestive heart failure. The presence of elevated serum BNP levels in other groups of patients with acute respiratory disease would limit the usefulness of serum BNP measurement. Additionally, elevated serum BNP levels in patients with respiratory failure due to COPD might suggest a role for right heart failure in these patients.
Enrolled patients had a new or existing diagnosis of COPD and were admitted to the intensive care unit (MICU at the enrolling institutions ) with acute respiratory failure and no evidence of acute left or right heart failure or myocardial ischemia. Enrolling institutions included Brooke Army Medical Center (BAMC) and Wilford Hall Medical Center (WHMC). The control population consisted of clinically stable patients with COPD enrolled in the outpatient setting. Measurements included brain natriuretic peptide (BNP), transthoracic echocardiogram, and pulmonary function testing when medically stable. ICU patients had competing diagnoses such as pneumonia, ischemia, congestive heart failure, or thromboembolic disease ruled out by appropriate clinical testing within the standard of care.
Seven inpatients were enrolled with an average BNP level of 320.4 were enrolled during this initial phase of the study. These seven patients were compared to seven stable COPD outpatients with moderate to severe COPD whose average BNP level was 21.4. Statistical analysis was performed using the Student t-Test for independent samples and a one tailed test of hypothesis was significant at the 0.05 level with a P value of 0.033.
BNP levels are significantly elevated in patient’s with moderate to severe COPD who are hospitalized in the intensive care unit with respiratory failure during an acute COPD exacerbation.
Elevated serum BNP levels in patients with respiratory failure due to COPD suggest a role for right heart failure in these patients. Further research is needed to determine possible treatments for ongoing right ventricular strain due to severe COPD.
Christopher Powers, None.