Evaluation of three spirometers on healthy children.

Two electronic spirometers (Dräger Spirotron and Monaghan M403) and one wedge bellows spirometer (Vitalograph) were compared with a Bernstein spirometer. Healthy children, 30 girls and 31 boys, were investigated. The regression lines of VC and FEV1.0 in relation to the body height to the third power are very close and the S.D. values around the lines are very similar. The correlation coefficients of the regression lines are high for all the spirometers. An analysis of the paired differences showed slight differences of the mean values. The S.D. of paired differences was for VC 4.6--6.6% and for FEV1.0 4.8--6.2%. The PEFR values obtained by the two electronic spirometers deviated substantially and highly significantly from the values obtained by the Wright peak flow meter.