Elevation of peak expiratory flow by a "spitting" maneuver: measured with five peak flowmeters.

STUDY OBJECTIVE To determine if peak expiratory flow (PEF) is higher using incorrect technique versus correct technique with five marketed peak flowmeters. DESIGN Randomized, nonblinded study. SETTING University pulmonary medicine clinic. PATIENTS Twenty adults with clinically stable asthma. INTERVENTIONS After inhaling 2 puffs of albuterol via a valved aerosol holding chamber (Aerochamber), patients were instructed over the next 15 min in correct and incorrect (a "spitting" action) technique when using peak flowmeters. Order of use of five peak flowmeters and correct vs incorrect technique was random. MEASUREMENTS AND RESULTS PEF (percentage of personal best) was recorded for best of three attempts with correct and incorrect technique. Each peak flowmeter had a statistically significant elevation in PEF with incorrect technique. The range for elevation in PEF using incorrect technique was 12.4 to 68.2% above the PEF with the subject using correct technique. CONCLUSION Each of the five marketed peak flowmeters had a significant elevation in PEF when a "spitting action" was used. Clinicians need to instruct patients carefully regarding correct technique when using peak flowmeters.