Exhaled nitric oxide levels in childhood asthma - A more reliable indicator of asthma severity than lung function measurement?

The level of exhaled nitric oxide (NO) has been demonstrated to reflect the degree of airway inflammation in patients with asthma and to be related to the severity of asthma, as well as to the efficacy of treatment. In contra st, lung function tests provide information about airway volumes and flows reflecting the level of airway obstruction, but do not allow any direct inf ormation about the degree of airway inflammation. Several studies have evaluated the relationships between the level of airwa y inflammation assessed by exhaled NO and the levels of airway obstruction and/or bronchial hyperresponsiveness in asthmatic adults and children. These studies highlight the complex pathophysiology of asthma and suggest t hat exhaled NO may have a promising role in addition to lung function measu rement in the evaluation of asthma severity in children.