An Evaluation of the Accuracy of Assess and MiniWright Peak Flowmeters: Discussion (2)

Many studies have been undertaken in the past to evaluate peak flowmeter performance. Many of these have used the Wright peak flowmeter as the standard of accuracy. Other have compared the peak flow measurements obtained with one model with that of others.
Only one study used a calibrated pneumotachometer as the standard of accuracy. Eichenhom et al examined three models of peak flowmeters (including the MiniWright and the original Healthscan meters) using a calibrated pneumotachometer. They did not correct their pneumotachometer readings for turbulence due to the altered direction of flow when a peak flowmeter is placed in series with a pneumotachometer, a problem that, in our experience, can alter the performance of any pneumotachometer.

In addition, the range of flow tested in this study was somewhat limited. Eichenhom et al believed that the original Healthscan meters, acting more as rotameters, were more accurate than those meters based on springs (MiniWright and Vitalograph), which were subject to varying length tension relationships.
Our data suggest that despite using a spring, the Assess peak flowmeter is linear, accurate, and retains its accuracy with use.