The peak flow working group: Test of portable peak flow meters by explosive decompression

In 1991, 50 new Vitalograph peak flow meters and 27 previously used mini-Wright peak flow meters were tested at three peak flows by use of a calibrator applying explosive decompression, The mini-Wright peak flow meters were also compared with eight new meters. For both makes of meter there was an excellent within-meter and between-meter variation, The accuracy, however, was poor, with a maximal overestimation of true flows of 50 and 70 L . min(-1) in the interval from 200 to 400 L . min(-1) for the Vitalograph and mini-Wright meters, respectively. The deviation is explained by the physical characteristics of the variable orifice peak flow meters. They have been supplied with equidistant scales, which give nonlinear readings.