PT  - JOURNAL ARTICLE
AU  - Mario Barreto
AU  - Anna Maria Bozzone
AU  - Francesca Ruggeri
AU  - Anna Prete
AU  - Valentina Negro
AU  - Susy Martella
AU  - Simona Liguori
AU  - Maria Pia Villa
TI  - Proximal and distal airway contributions of nitric oxide in atopic asthmatic and healthy children. Estimates from two series of multiple exhalation flows
DP  - 2012 Sep 01
TA  - European Respiratory Journal
PG  - P1108
VI  - 40
IP  - Suppl 56
4099  - http://erj.ersjournals.com/content/40/Suppl_56/P1108.short
4100  - http://erj.ersjournals.com/content/40/Suppl_56/P1108.full
SO  - Eur Respir J2012 Sep 01; 40
AB  - Background. Partitioned contributions of nitric oxide (NO) are being studied to assess atopic airway inflammation in asthma. Selection of flow rates could influence data on disease or atopy.Aims. To compare partitioned airway NO concentrations in asthmatic and healthy children using two different series of exhalation flows.Methods. In 30 asthmatic and 21 healthy children aged 11.2±2.5 yr, 35 males, we measured the fractional NO concentration (FENO) at multiple exhalation flows: 50, 100, 150 and 350 ml/s. From two series of either 3 (50-150) and 4 (50-350 ml/s) flow rates, the alveolar NO concentration (CaNO3, CaNO4) and the maximum airway NO flux (J'awNO3, J'awNO4) were calculated. Spirometry and skin-prick testing for common allergens were assessed.Results. Asthmatic children had lower lung function and higher median (IQR) FENO, CaNO3, J'awNO3 and J'awNO4 but no different CaNO4 than healthy children [J'awNO3:1140.0 (2105.8) nl/s vs 506.6 (585.8) nl/s, p=0.001]. Patients using inhaled corticosteroids, ICs (n=11) had lower CaNO3 than those steroid-naive (n=19): 2.99 (6.82) vs 8.84 (8.38) ppb, p=0.001. All NO-related variables but CaNO4 correlated with house dust mites (Dpt, Dpf) and cat fur (e.g. with Dpt, CaNO3: r=0.57, J'awNO4: r=0.50, p<0.01). In healthy children, CaNO4 correlated with FEF25-75% (r=0.81, p=0.000).Conclusion. Estimates of partitioned airway NO concentrations from exhalation flows 50-150 ml/s help to evaluate atopic airway inflammation; CaNO3 is suitable to assess ICs therapy in asthmatic children. A further exhalation flow 350 ml/s, do not improve peripheral NO estimates and probably induces airway collapse.