Usefulness of peak expiratory flow measurements: is it just a matter of instrument accuracy?

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Abstract
A method for improving the accuracy of peak flow meters will be valuable if the recommendation to measure PEF is to be maintained in asthma management plans. With the currently available peak flow meters, no evidence has been provided that PEF measurements are of clinical usefulness. A large number of new randomised controlled studies using optimally validated peak flow meters would therefore be necessary. However, by that time these instruments may have become obsolete. In this issue of Thorax Miller et al 1 present a new method for validation of peak flow meters. They show that applying a computer driven explosive decompression can detect inaccuracies in the dynamic response of commercially available peak flow meters that would be missed using the ATS recommended 26 waveforms for spirometer validation. This work is justified by the compelling recommendations to use peak expiratory flow (PEF) as a main or sole measure of lung function, incorporated in the current guidelines for diagnosis and management of asthma.2–5 In particular, PEF is recommended for daily home monitoring and also as a criterion for admission and discharge from the emergency room. For either application, accuracy of measurement is an obvious prerequisite. Indeed, previous works have shown that commercially available peak flow meters may not be accurate enough to allow correct management of …