Forced inspiratory flow volume curve in healthy young children

Spirometry testing should include both expiratory and inspiratory measurements. Inspiratory forced maneuvers can demonstrate extrathoracic airway abnormalities, of which various symptoms may suggest asthma. However, the inspiratory portion of the forced flow/volume maneuver in young healthy children has not yet been described.

To document and analyze the forced inspiratory flow volume curve indices in healthy young children.

Healthy preschool children (age 2.5-6.5 years) from community kindergartens around Israel.

The teaching method included multi-target, interactive spirometry games and accessory games for inspiration (e.g., inspiratory whistle).

One hundred and fourteen out of a total 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 (IC), forced inspiratory vital capacity (FIVC), peak inspiratory flow (PIF), and mid inspiratory flow (FIF50). Inspiratory flow indices were significantly lower than the expiratory flow indices. The time to reach PIF was significantly longer (mean +/- SD; 229 +/- 21 msec) than the time to reach peak expiratory flow (92 +/- 8 msec; P < 0.0001). The shape of the inspiratory curve was parabolic and did not vary with age. The formed predicted equations were in agreement with the extrapolated values for older healthy children.

The majority of healthy young children can perform reliable maximum inspiratory flow volume curves. Our results provide a framework of reference equations for maximum inspiratory flow volume curve in the young children. The clinical applications of these equations have to be explored.