Effect of device and expiratory maneuver technique on peak expiratory flow measurements

Peak expiratory flow (PEF) obtained from dedicated PEF meters and various types of spirometers is often used interchangeably in research, despite differences in both devices and expiratory maneuver technique. The aim of this study was to assess the effects of expiratory maneuver type and measurement device on PEF.

We recruited 20 healthy adults experienced in performing spirometry. Each subject performed three measurements using two expiratory maneuvers (a short, explosive maneuver and a long, spirometry-style maneuver) with four devices: the handheld microspirometers Medikro Duo and MIR Spirobank, the laboratory spirometer Vyntus Pneumo, and the Mini-Wright PEF meter.

PEF differed significantly between devices (F(3,133) = 171.8, p < 0.001), but not between short and long expiratory maneuver techniques (F(1,133) = 2.24, p = 0.137). There was no significant interaction between device and technique (F(3,133) = 0.72, p = 0.543). Compared with the Mini-Wright, Spirobank yielded PEF values that were on average 87.1 L/min higher (74.6-99.7, p < 0.001), and Vyntus Pneumo 26.5 L/min higher (14.0-39.1, p < 0.001), whereas Medikro did not differ significantly from the Mini-Wright (mean difference -9.5 L/min, -22.1-3.1, p = 0.269). The pairwise differences between the three spirometers were all statistically significant (all p < 0.001).

Because short and long expiratory maneuver techniques yield similar results on PEF, future studies of home spirometry may compare the diagnostic performance of PEF and forced expiratory volume in 1 s (FEV₁) using the same long, spirometry-style expiratory maneuvers. However, comparison of absolute PEF values between devices must be done cautiously.