Comparison of peak expiratory flow rate with speaking time in ED patients presenting with acute exacerbation of asthma.

Thirty-six patients with a history of asthma who presented to an emergency department (ED) with an acute exacerbation were studied prospectively to determine if a correlation existed between peak expiratory flow rate (PEFR) and speaking time. Each patient listened to an instructional audiotape on the proper method of counting and then maximally inhaled and counted until it became necessary to take a second breath. This represented the patient's "speaking time" in seconds. A PEFR was then obtained using a hand-held peak flow meter. The speaking time and PEFR were measured before and after each nebulized albuterol treatment. A total of 169 pairs of pretreatment and posttreatment PEFR and speaking time measurements were obtained. Regression analysis of the PEFR and speaking time demonstrated the PEFR can be predicted by the speaking time with statistical significance (P < .0001). The regression analysis equation was: peak flow (L/min) = 114.8 +/- (17.6 x speaking time).