RT Journal Article
SR Electronic
T1 Dissociation between exhaled nitric oxide and hyperresponsiveness in children with mild intermittent asthma
JF Thorax
JO Thorax
FD BMJ Publishing Group Ltd and British Thoracic Society
SP 484
OP 488
DO 10.1136/thorax.55.6.484
VO 55
IS 6
A1 Michela Silvestri
A1 Daniela Spallarossa
A1 Elena Battistini
A1 Vito Brusasco
A1 Giovanni A Rossi
YR 2000
UL http://thorax.bmj.com/content/55/6/484.abstract
AB BACKGROUND Bronchial hyperresponsiveness and airway inflammation are distinctive features of asthma. Evaluation of nitric oxide (NO) levels in expired air have been proposed as a reliable method for assessing the airway inflammatory events in asthmatic subjects. A study was undertaken to evaluate whether airway hyperresponsiveness is related to levels of exhaled NO.METHODS Thirty two steroid-naive atopic children with mild intermittent asthma of mean (SD) age 11.8 (2.3) years and 28 age matched healthy controls were studied to investigate whether baseline lung function or airway hyperresponsiveness is related to levels of exhaled NO. Airway responsiveness was assessed as the dose of methacholine causing a 20% decrease in forced expiratory volume in one second (FEV1) from control (PD20 methacholine) and exhaled NO levels were measured by chemiluminescence analysis of exhaled air.RESULTS At baseline asthmatic children had significantly higher NO levels than controls (mean difference 25.87 ppb (95% CI 18.91 to 32.83); p<0.0001) but there were no significant differences in lung function parameters (forced vital capacity (FVC), FEV1 (% pred), and forced expiratory flows at 25–75% of vital capacity (FEF25–75%)). In the asthmatic group exhaled NO levels were not significantly correlated with baseline lung function values or PD20 methacholine.CONCLUSIONS These results suggest that levels of exhaled NO are not accurate predictors of the degree of airway responsiveness to inhaled methacholine in children with mild intermittent asthma.