Can peak expiratory flow measurements differentiate chronic obstructive pulmonary disease from congestive heart failure?

Dyspneic patients are commonly encountered by Emergency Medical Service (EMS). Frequent causes include Chronic Obstructive Pulmonary Disease (COPD) and Congestive Heart Failure (CHF). Measurement of peak expiratory flow rate (PEFR) has been proposed to help differentiate COPD from CHF. This prospective, cohort, pilot study was conducted to determine if PEFR in patients with an exacerbation of COPD were significantly different than CHF. Included were patients presenting with dyspnea plus a history of COPD and/or CHF. A PEFR was measured, values were compared to predicted average, and a percentage was calculated. Twenty-one patients were enrolled. Six had a diagnosis of COPD, 12 CHF; 3 had other diagnoses. Mean percentage of predicted PEFR with COPD was 26.36%, CHF 48.9% (P = 0.04). Patients presenting with acute COPD had significantly lower percentage of predicted PEFR than those with CHF. These results suggest that PEFR may be useful in differentiating COPD from CHF. This study should be expanded to the prehospital setting with a larger number of subjects.