Tidal volume forced expiration in asthmatic infants: reproducibility and reversibility tests.

Background: The tidal volume forced expiration technique used in infants is considered as the first practical noninvasive method of assessing airway physiology in infants. However, its role has been discussed mainly due to the high variability of the derived parameters.

Objectives: The aim of the study was to assess the reproducibility of a complete measurement with the tidal volume forced expiration technique in infants as measured by the maximal flow at FRC (V(max)FRC).