Clinical evaluation of five spirometers. Monaghan M403, Pneumoscreen, Spirotron, Vicatest and Vitalograph.

Five spirometers were compared with the Stead-Wells spirometer in 100 subjects, using the FVC and FEV1 as parameters. In addition, some physical characteristics were studied. The Stead-Wells is a water-sealed spirometer, recommended as a reference spirometer by the American Committees on Environmental Health and Respiratory Physiology. The Vicatest and Vitalograph are volume-displacement dry spirometers. They showed a very good linearity over their entire volume ranges; their FVC and FEV1 readings showed very good correlations with the readings of the Stead-Wells spirometer. The Monaghan, Pneumoscreen, and Spirotron are flow-integrating "electronic" spirometers. The volumes recorded were found to be dependent on the values of the flow; their FVC and FEV1 readings also showed good correlations with the readings of the Stead-Wells spirometer, but to a lesser extent than the two dry spirometers. Therefore, for routine assessment of ventilatory function we prefer, at present, the modern volume-displacement dry spirometers.