Exhaled nitric oxide measurements in hospitalized children with asthma

The reproducibility of exhaled nitric oxide (FE(NO)) measurements performed in pediatric hospitalized asthmatics has not been previously evaluated.

To evaluate the reproducibility of FE(NO) measurements in the hospital; to look for differences between those who were and were not able to perform FE(NO) measurements; and to assess any factors correlated with FE(NO) measurements.

89 hospitalized pediatric asthmatics performed FE(NO), FEV1, and peak expiratory flow rate (PEFR) maneuvers in triplicate at the time of discharge. Reproducibility was assessed using the intraclass correlation coefficient (ICC) and coefficient of variation (CV). Demographic and measured variables were compared between those who were and were not able to perform FE(NO) measurements. Correlation of FE(NO) with other variables was investigated.

FE(NO) measurements showed clinically acceptable ICC and CV values (0.973 and 5.59%, respectively). These values were superior to the values obtained for FEV1 and PEFR. Subjects who successfully performed the FE(NO) measurements were older, had higher PEFR readings, and had a lower asthma dyspnea score. No correlation was found between FE(NO) and traditional asthma factors, though multiple factors did trend towards significance.

FE(NO) measurements can be obtained in hospitalized pediatric patients with good reproducibility. While the majority of children will be able to provide such readings, those who are younger and with a more severe exacerbation may be unsuccessful in doing so. Further research is needed to determine how best to incorporate FE(NO) values into the hospital setting.