Exhaled Nitric Oxide and Airway Caliber in Children With Asthma

The purpose of this study is to assess if in steroid naïve asthmatic children with elevated baseline exhaled nitric oxide, treatment with inhaled steroid and normalization of exhaled nitric oxide level results in restoration of the bronchodilator response to deep inhalation.

Previous studies have shown that a deep inhalation (DI) would increase airway caliber in normal subjects. Whereas in asthmatics with spontaneous bronchoconstriction (obstruction of the airway), DI was shown to worsen airway obstruction. The mechanism for this variability in response to DI is not well-understood, but seems to be a key in understanding the pathophysiology of the disease, and possibly in the development of an effective therapy. Air way inflammation resulting in airway wall thickening and peribronchial edema is thought to play a role how the airway responds to deep inhalation. This study assess if reduction in airway inflammation (as measured by level of exhaled NO)results in optimization of the bronchodilator response to deep inhalation