[Assessment of 2 portable peak expiratory flow meters and reference values for students 6 to 16 years of age]

This study examines the technical characteristics of two different peak expiratory flow meters, of high range, and the reference values of peak expiratory flow (PEF) for schoolchildren.

The gauge accuracy and precision were previously determined in 20 units of each model (PF-Control and Mini-Wright), with a syringe servocontrolled by simulating 4 predetermined PEF fluxes (125, 262, 424 and 587 L/min). Relatives were asked about passive smoking and the childhood background concerning asthma, recurrent bronchitis or recent respiratory infection. The PEF of 1,142 schoolchildren, 669 boys and 473 girls between 6 and 16 years of age and coming from 6 different locations of different demographic and social characteristic of Catalonia, Spain, were measured.

Readings of both gauges differed in accuracy, although they presented a good intradevice precision. The PF-control is within the reliance intervals for fluxes of 425 and 587 L/min, with a suprareading of 15.3% for the 262 L/min and infrareading of 19.2% for the 125 L/min controls. Flux with the Mini-Wright shows systematic over-reading of between 17.9% and 30.2%, with an accurate reading only in the 587 L/min control flux. No significant correlation was found between the PEF and family passive smoking (56.3%), pupils with asthma background (7.1%), recurrent bronchitis (11%) or recent respiratory infection (7.7%).

The accuracy difference forces the use of diverse percentile tables for each of the PEF gauge patterns; hence, we present the reference tables for each gauge, in means of 10, 50 and 90 percentiles, which can be used as reference values for our school population according to their age, size and sex.