Forced Inspiratory Flow Volume Curve in Healthy Young Children

Spirometry testing should include both expiratory and inspiratory measurements as it may influence the expiratory flow volume curve indices. The ability to inhale medication may by judged by inspiratory flows. However, the inspiratory portion of the forced flow/volume maneuver in young healthy children has not yet been described.Objectives: To document and analyze the forced inspiratory flow volume curve indices in healthy young children. Settings: Community kindergartens around Israel. participants; Healthy preschool children (age 2.5-6.5 years). Methods: The teaching method included multi-target, interactive spirometry games (SpiroGame®) and accessory games for inspiration (e.g. inspiratory whistle). Results: One hundred and fourteen of 157 children performed duplicate full adequate inspiratory maneuvers. Repeatability between two maneuvers was 5.6%, 4.0%, 5.1%, 7.3% for inspiratory capacity (IVC), forced inspiratory capacity (FIVC), peak inspiratory capacity (PIF), and mid inspiratory flow (MIF50), respectively. Inspiratory flow indices were significantly lower than the parallel expiratory flow indices and the time to reach PIF was significantly slower than the time to reach peak expiratory flow (meanSD; 22921ms vs. 92 8ms; p\<0.0001). The shape of the inspiratory curve was parabolic and did not change with age. Predicted equations that were formed were in agreement with the extrapolated prediction equation values of older children. We found that the majority of healthy young children can produce reliable inspiratory curves. Our results provide a framework for reference equations for inspiratory flow volume curve in the young ages. The clinical applications of these equations are yet to be explored.