Relationship Between Fractional Exhaled Nitric Oxide (FeNO) and Forced Expiratory Volume in One Second (FEV1) and Forced Vital Capacity (FVC) in Children with Asthma

Background: Measurement of fraction of exhaled nitric oxide (FeNO) is a relatively simple, noninvasive, and reproducible test for detection of endogenous inflammatory signals in childhood. The aim of this study was to evaluate the correlation between FeNo levels and forced vital capacity (FVC) and forced expiratory volume in the first second (FEV1) in a group of steroid-naive childhood asthma.

Methods: The study was conducted in a group of 60 steroid-naive asthmatic children (50 atopic and 20 nonatopic; mean age 7 years) who presented to Kyung Hee University Hospital and 20 healthy children. All patients underwent measurement of FeNO, skin prick tests with common inhaled allergens, and blood eosinophil, and flow-volume spirometry. FeNO levels were measured by chemiluminescence during exhalation into the NO analyzer. Measurements of FeNO in parts per billion (ppb) and spirometry, including FEV1 and FVC, were performed.

Results: Compared to the healthy volunteers, FeNO was elevated in both groups of asthmatics. The mean FeNO level in the asthmatic children was 18.6 ppb. FeNO in the atopic asthma group was higher than in the group of nonatopic asthmatics. There was statistically significant correlation between FeNO levels and FEV1 (r = -0.36, p < 0.016) and FVC (r = -0.40, p < 0.01).

Conclusions: FeNO levels were related with pulmonary functions in childhood asthma. Thus measurement of FeNO is a promising clinical tool for assessing asthma.