AMBULATORY MONITORING OF PEAK EXPIRATORY FLOW - REPRODUCIBILITY AND QUALITY-CONTROL

Eighty-five children and 230 adults from a population study performed ambulatory peak now readings three times a day for 1 to 2 weeks follow ing a home visit. Three peak expiratory flow (PEF) readings were repor ted for each of 5,809 test sessions. Within each test session, the thi rd maneuver most frequently (40% of the time) gave the highest PEF rea ding. This did not vary throughout the day. In subgroups of children a nd women with a history of asthma or asthma symptoms (hereinafter refe rred to as ''asthma''), the first maneuver during the evening test ses sions more frequently gave the highest readings. However, maneuver-ind uced bronchospasm occurred during less than 5% of the test sessions in both subjects with asthma and in other subjects. The within test sess ion PEF reproducibility was good: overall, the highest and second high est reading matched within one division (10 L/min) 73% of the time and within 30 L/min (9% of the reading) 95% of the time. The best reprodu cibility was noted after the first two days of testing, during evening and bedtime test sessions (vs morning), and in girls and men. In the group with at least 2 weeks of testing, the coefficient of repeatabili ty (CR) for the week-to-week PEF lability index was 10% for healthy ad ults and 17% for healthy children. As expected, repeatability was not as good for adults with asthma (CR = 17%) and children with asthma (CR = 28%).