In adults and older children the measurement of fractional exhaled nitric oxide (FENO) has been shown to be useful as a tool to diagnose and monitor eosinophilic airway inflammation. However, the recommended method to measure FENOin school-age children is not suited for use in preschool children and infants. This article reviews the data on FENOmeasurements in infants. In the first year of life, measurement of FENOcan be done during tidal breathing or during a single forced passive expiration. Several technical factors, including contamination with nasal and ambient NO, and the influence of expiratory flow influence FENOlevels in infants. Because asthma is uncommon in infants and wheezing is often related to viral infections, considerable differences in clinical utility of FENObetween older children and infants could be expected. From the available data FENOcould potentially be useful to identify early-onset asthma, to diagnose primary ciliary dyskinesia (PCD), and to monitor the effect of various treatments. In conclusion, there is still much uncertainty about the potential clinical utility of FENOin infants. There is a need for clinical studies showing the merits and limitations of different methodologies, to standardize FENOmeasurements in infants, and to obtain normal reference values for this age group. Copyright

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Seminars in Respiratory and Critical Care Medicine
Erasmus MC: University Medical Center Rotterdam

van Mastrigt, E., Gabriele, C., & de Jongste, J. (2007). Exhaled nitric oxide in infants - What is a nice test like FENO doing in a place like this?. Seminars in Respiratory and Critical Care Medicine (Vol. 28, pp. 264–271). doi:10.1055/s-2007-981647