[Quality control for maximal expiratory flow-volume curve as a pulmonary function test in school-age children].

Objective: To assess the quality control for the maximal expiratory flow-volume (MEFV) curve in school-age children.

Methods: Eight hundred and sixty-two children who had two or more MEFV manoeuvres were classified into ≥6-year-old (n=379), ≥8-year-old (n=210), ≥10-year-old (n=64), and 12-17-year-old groups (n=109). The parameters of quality control and concordance with quality control criteria for MEFV were compared between the two groups. In addition, patients who were diagnosed with asthma were classified into two groups, one with normal pulmonary function (n=155) and the other with abnormal pulmonary function (n=62), based on the results of spirometry. Differences in the parameters of quality control for spirometry were compared between the two groups.

Results: Eight hundred and sixty-two children underwent 2 367 MEFV manoeuvres, 97.8% of which met the start of test criterion for backward extrapolated volume (VBE) of less than 0.15 L, with the highest concordance in the ≥6-year-old group and the lowest concordance in the 12-17-year-old group. Three hundred and eighty-one children (44.2%) met the end of test criterion for forced expiratory time (FET) and the concordance in children over 10 years of age was lower than that in children under 10 years of age (P<0.05). Differences in two best forced expiratory volume in first second (FEV1) and forced vital capacity (FVC) manoeuvres were within 150 mL in 91.9% and 84.8%, respectively, of the children. The parameters of quality control for spirometry were better for asthmatic children with abnormal pulmonary function compared with asthmatic children with normal pulmonary function (P<0.05).

Conclusions: Concordance with the start of test criteria and the manoeuvre repeatability criteria is high, whereas the concordance with the end of test criteria is low. It is suggested that the concordance with the FET criteria should be improved.