Technical and Functional Assessment of 10 Office Spirometers: Assessment of User Friendliness

We developed a novel questionnaire to assess the user friendliness of office spirometers (to view Tables A and B in the on-line supplementary data, go to www.chestnet.org). The questionnaire completed by the three GPs covered the following: general properties and parameters of the software, quality of the patient administrative data, features of the display and automated quality control, comparison of successive tests in the same subject, use at home visits, and export facilities. The precision of the office spirometers was assessed by the Sw of FEV1 and FVC obtained from five successive maneuvers done by the nine ETs with the office spirometers and with the standard spirometers. The larger the Sw value, the lower the precision. The variance of each set of five measurements (FVC, FEV1) was computed, and the within-subject variance of the measurements was obtained by averaging the nine variances. To obtain the 95% error limits, the square root of the within-subject variance was multiplied by 1.96. We used goals for within-session repeatability for FEV1 and FVC of 200 mL, as our upper limits of precision. website
The preliminary analyses revealed no difference between the populations studied, so the results of the PFTs done in the three centers were pooled for each office spirometer. The agreement and the bias between the standard and office spirometers were examined using Bland and Altman analysis. The bias (mean difference between the office spirometers and the standard spirometers), its 95% confidence interval (CI), and the lower and upper limits of agreement between office spirometers and standard spirometers were reported. A statistical significant correlation (p < 0.05) indicates the presence of a proportional difference between the devices. We fixed the upper limits of acceptable bias at ± 100 mL according to the ATS accuracy criteria for diagnostic devices. The acceptable limits of agreement between the office spirometers and the standard spirometers were 350 mL and 500 mL for FEV1 and FVC, respectively. These limits were fixed according to the short-term coefficient of variability of FEV1 and FVC measured in COPD patients.

This entry was posted in Spirometers and tagged comparative study, COPD detection, pulmonary function tests, spirometer, spirometry.