Studying the role of alveolar exhaled nitric oxide in combination with bronchial nitric oxide to predict asthma control in children with asthma: A real-life prospective study

Fractional exhaled nitric oxide (FENO) is currently used as a biomarker of airway inflammation in patients with asthma. However, the role of alveolar nitric oxide (CANO) in asthmatic children has not been clearly demonstrated It was a prospective and descriptive study. The measurement of FENO and CANO, spirometry, blood eosinophil counts (BEC), and total IgE levels were performed for each study subject. This study included 109 uncontrolled asthmatic children without inhaled corticosteroid (ICS) treatment. The exhaled NO level in asthmatic patients was significantly higher than in control subjects: FENO: 22.5 vs. 8.4 ppb; CANO: 5.9 vs. 2.8 ppb; J’awNO (maximum airway nitric oxide flux): 56.9 vs. 18.7 ppb; respectively. The sensitivities and specificities for asthma diagnosis with the cut-off of CANO at 3.5 ppb and 5.0 ppb were 74.3% and 73.3%, and 46.0% and 83.3%, respectively. There were the moderate and the weak correlations between CANO with FENO and CANO with IgE in asthmatic patients (r = 0.465, 95%CI (0.133-0.659), P=0.001; r=0.133, 95%CI (0.068- 0.497), P=0.184; respectively). The percentage of controlled asthma in patients with CANO ≥5 ppb at inclusion was higher than that in CANO <5 ppb group. Exhaled NO is a relevant biomarker of allergic asthma. The level of FENO and CANO might be used to predict asthma control in children.