@article {Boutin107, author = {Bernard Boutin and Marc Koskas and Houda Guillo and Lucia Maingot and Marie-Claude La Rocca and Mich{\`e}le Boul{\'e} and Jocelyne Just and Isabelle Momas and Alberti Corinne and Nicole Beydon}, title = {Forced expiratory flows{\textquoteright} contribution to lung function interpretation in schoolchildren}, volume = {45}, number = {1}, pages = {107--115}, year = {2015}, doi = {10.1183/09031936.00062814}, publisher = {European Respiratory Society}, abstract = {Forced expiratory flow (FEF) at low lung volumes are supposed to be better at detecting lung-function impairment in asthmatic children than a forced volume. The aim of this study was to examine whether FEF results could modify the interpretation of baseline and post-bronchodilator spirometry in asthmatic schoolchildren in whom forced expiratory volumes are within the normal range. Spirometry, with post-bronchodilator vital capacity within 10\% of that of baseline in healthy and asthmatic children, was recorded prospectively. We defined abnormal baseline values expressed as z-scores \<-1.645, forced expiratory volume in 1 s (FEV1) reversibility as a baseline increase \>12\%, FEF reversibility as an increase larger than the 2.5th percentile of post-bronchodilator changes in healthy children. Among 66 healthy and 50 asthmatic schoolchildren, only two (1.7\%) children with normal vital capacity and no airways obstruction had abnormal baseline forced expiratory flow at 25{\textendash}75\% of forced vital capacity (FEF25{\textendash}75\%). After bronchodilation, among the 45 asthmatic children without FEV1 reversibility, 5 (11.1\%) had an FEF25{\textendash}75\% increase that exceeded the reference interval. Isolated abnormal baseline values or significant post-bronchodilator changes in FEF are rare situations in asthmatic schoolchildren with good spirometry quality. Forced expiratory flows don{\textquoteright}t add useful information over forced expiratory volumes and their ratio in schoolchildren http://ow.ly/zo5MA}, issn = {0903-1936}, URL = {https://erj.ersjournals.com/content/45/1/107}, eprint = {https://erj.ersjournals.com/content/45/1/107.full.pdf}, journal = {European Respiratory Journal} }