Measurement of Fractional Exhaled Nitric Oxide in Stable Bronchiectasis

BACKGROUND: Fractional exhaled nitric oxide (FeNO) can be measured easily, rapidly, and noninvasively for the assessment of airway inflammation, particularly mediated by eosinophil, such as asthma. In bronchiectasis (BE), the pathogenesis has been known as chronic airway inflammation and infection with abnormal airway dilatation; however, there are little studies to evaluate the role of FeNO in BE. METHODS: From March 2010 to February 2012, 47 patients with BE, diagnosed by high resolution computed tomography (HRCT), performed FeNO, compared with asthma and chronic obstructive pulmonary disease (COPD). All patients carried out a complete blood count including eosinophil count, chemistry, sputum examination, and spirometry, if indicated. A retrospective analysis was performed to elucidate the clinical role of FeNO in BE patients. RESULTS: The mean FeNO levels in patients with BE was 18.8±1.5 part per billion (ppb), compared to 48.0±6.4 and 31.0±4.3 in those with asthma and COPD, respectively (p<0.001). The FeNO levels tended to increase along with the disease severity scores by HRCT; however, it was statistically not significant. FeNO in BE with a co-infection of nontuberculous mycobacteria was the lowest at 17.0±3.5 ppb among the study population. CONCLUSION: FeNO in BE was lower than other chronic inflammatory airway diseases, particularly compared with asthma. For clinical application of FeNO in BE, more large-scaled, prospective studies should be considered.