Fig. 3.

Comparison of 2-compartment and multicompartment models. A: total airway flux as determined by least-squares fitting the 2-compartment and multicompartment models to 20 children with asthma. Average predicted total airway NO flux for the multicompartment model was the sum of all 3 airway flux terms. B: average alveolar NO concentration determined by 2-compartment and multicompartment models. Average concentration was determined by volume weighting the 2 alveolar NO concentrations in the multicompartment model. Both models predicted similar NO levels on average (horizontal bars). C: percent improvement in residual sum of squares (RSS) between the 2-compartment and the multicompartment model as a function of the phase III slope of NO. There was a statistically significant negative correlation (solid line represents best-fit linear regression). See Glossary for abbreviations.