RT Journal Article
SR Electronic
T1 Comparison of alveolar nitric oxide concentrations using two different methods for the assessment of small airways inflammation in asthma
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP p4783
VO 38
IS Suppl 55
A1 Daiki Kobayashi
A1 Yoshihiro Tochino
A1 Hiroshi Kanazawa
A1 Yukikazu Ichimaru
A1 Kyoh Shigenori
A1 Kazuhisa Asai
A1 Kazuto Hirata
YR 2011
UL http://erj.ersjournals.com/content/38/Suppl_55/p4783.abstract
AB Background and objectives: Fractional exhaled nitric oxide (FENO) is considered a potentially useful biomarker to detect airway inflammation. Two-compartment model (2CM) of pulmonary NO dynamics has been used for the evaluation of bronchial NO flux (J'awNO) and peripheral airway/alveolar NO concentration (CANO) in asthmatic patients. Recently, the trumpet shape of airway tree and axial diffusion model (TMAD) has been reported as the correction of 2CM. This study was designed to determine the validity of measurement of CANO using the TMAD model for the assessment of small airways obstruction in asthmaMethods: A total of 52 asthmatic patients and 12 normal controls were included in this study. Methacholine inhalation challenge testing, pulmonary function tests, sputum induction, and exhaled NO measurements at several flow rates were performed. And then J'awNO and CANO were calculated using both the 2CM (CANO 2CM, J'awNO 2CM) and the TMAD model (CANO TMAD, J'awNO TMAD) respectively.Results: Both J'awNO and CANO were significantly higher in asthmatic patients than normal controls. CANO 2CM was significantly correlated with FEV1/FVC (r=-0.35, p=0.01), FEF25-75 (r=-0.45, p<0.001), and sputum eosinophils (r=0.32, p=0.02). In contrast, CANO TMAD was significantly correlated with FEF25-75 alone (r=-0.42, p=0.002), and not with FEV1/FVC or sputum eosinophils.Conclusions: CANO TMAD is more selective as an indicator of small airways obstruction than CANO 2CM. Assessment of small airways obstruction using the TMAD model may reveal the role of the small airways in the pathogenesis of asthma.