Fraction of exhaled nitric oxide and asthma predictive index in infants less than two years-old.

Introduction: The fraction of exhaled nitric oxide (FE(NO)) is considered as an indirect marker of eosinophilic inflammation of the airway. In collaborating children the usual method is by a single breath. The impossibility of performing this in non-collaborating children has led to the development of the online and offline tidal breathing technique.