Global Lung Initiative spirometry references in healthy 3-15-year-old French children.

Global Lung Initiative spirometry references satisfactorily fit data of healthy 3- to 15-year-old French children http://bit.ly/2Z2922R.

Quantification of shape of flow-volume loop of healthy preschool children and preschool children with wheezing disorders.

BACKGROUND: The earliest change associated with airflow obstruction in small airways is reflected in a concave shape on the maximum expiratory flow-volume loop (MEFVL). The shape of the MEFL changes with age but reference values for curvilinearity indices (CI) for preschool children have not been published. We aimed to describe the normal curvilinearity of healthy preschool MEFVL by CI (the ß angle and the ratio of maximum expiratory flow when 50% of forced vital capacity remains to be expired/peak expiratory flow (MEF(50%) /PEF)) and to test their capacity in detecting concavity in preschool children with wheezing disorders. METHODS: Spirometric data were obtained from 132 healthy preschool children and 171 3-to-5-year-old preschool children with wheezing disorders and reference values for CI calculated. RESULTS: Mean (SD) ß angle of healthy children was 203° (16°) and mean MEF(50%) /PEF of healthy children was 0.71 (0.12) indicating convexity of MEFVL, both decreased with increasing age (P = 10(-4) ). Children with wheezing disorders had lower z-score values of CI (P ≤ 10(-6) ) indicating more concave MEFVL. Among the two CI, MEF(50%) /PEF allowed for the best discrimination between healthy children and children with wheezing disorders (Wilks' lambda = 0.898, P = 10(-7) ). CONCLUSION: These CI can detect and quantify the concavity of the descending limb of the MEFVL in preschool children with wheezing disorders, MEF(50%) /PEF having the highest sensitivity in detecting the concavity.

Spirometry in 3-5-year-old children with asthma.

Spirometry with incentive games was applied to 207 2-5-year-old preschool children (PSC) with asthma in order to refine the quality-control criteria proposed by Aurora et al. (Am J Respir Crit Care Med 2004;169:1152-159). The data set in our study was much larger compared to that in Aurora et al. (Am J Respir Crit Care Med 2004;169:1152-159), where 42 children with cystic fibrosis and 37 healthy control were studied. At least two acceptable maneuvers were obtained in 178 (86%) children. Data were focused on 3-5-year-old children (n = 171). The proportion of children achieving a larger number of thresholds for each quality-control criterion (backward-extrapolated volume (Vbe), Vbe in percent of forced vital capacity (FVC, Vbe/FVC), time-to-peak expiratory flow (time-to-PEF), and difference (Delta) between the two FVCs (DeltaFVC), forced expiratory volume in 1 sec (DeltaFEV(1)), and forced expiratory volume in 0.5 sec (DeltaFEV(0.5)) from the two "best" curves) was calculated, and cumulative plots were obtained. The optimal threshold was determined for all ages by derivative function of rate of success-threshold curves, close to the inflexion point. The following thresholds were defined for acceptability: Vbe