Peak expiratory flow (PEF) monitoring.

T he Wright peak expiratory flow meter was introduced in 1959 and provided a portable piece of equipment for assessing some aspects of lung function in the ambulatory care setting. The original device has been supplanted by the mini Wright peak flow meter (and a range of other devices) which have become relatively cheap but are reasonably reliable for home monitoring. So, with an available device for measuring peak expiratory flow (PEF), what is its role in the 21st century? PEF reflects a range of physiological characteristics of the lungs, airways, and neuromuscular characteristics of individuals. These include lung elastic recoil, large airway calibre, lung volume, effort, and neuromuscular integrity. The reflection of airway calibre makes the PEF meter suitable for measuring variation in PEF over time to provide support for: