Evaluation of a pocket-sized turbine spirometer for clinical use with children

The results of pulmonary function testing with a turbine spirometer (TS) and a bell spirometer (BS) of a randomized group of 275 patients aged 4-18 years were compared. In the TS, an inexpensive device without graphical display was used. The difference BS minus TS (d) for forced expiratory volume in 1 s (FEV1) was calculated. The results indicate that the FEV1 might be overestimated by the TS, and that the difference of the readings of FEV1 between the spirometers increases with airway obstruction. The TS should be used with caution in young patients with asthma.