Utility of the peak expiratory flow rate in the differentiation of acute dyspnea. Cardiac vs pulmonary origin.

This study examined the utility of a peak expiratory flow rate (PEFR) measurement in the differentiation of acute moderate to severe dyspnea secondary to congestive heart failure or chronic lung disease. A PEFR was determined in 41 episodes of acute respiratory distress in 40 patients prior to emergency department therapy. The mean PEFR +/- SD for the congestive heart failure group (n = 18) was 224 +/- 82 L/min, which was significantly higher (p less than 0.001) than that of the chronic lung disease group (n = 23), which had a mean PEFR of 108 +/- 49 L/min. No single cutoff value allowed 100 percent accurate classification, but the results suggest that the PEFR may be a useful adjunctive tool in the differentiation of acute dyspnea of cardiac vs pulmonary origin.