Exhaled nitric oxide in the clinical management of asthma

Management of asthma has gradually evolved from the concept of controlling bronchial hyperresponsiveness to focusing on control of inflammation. The awareness of airway remodeling, and the emergence of data suggesting irreversibility of some of these changes, despite standard-of-care pharmacotherapies such as inhaled steroids, has highlighted the need for early detection; effective diagnosis and treatment; monitoring responses and adhering to treatment; and predicting exacerbations. Pre-clinical intervention strategies targeted toward picking up early suggestions of asthma before irreversible airway changes occur may open the door to primary prevention approaches. Although invasive methods, such as bronchial biopsy, remain the gold standard to understanding and treating asthma, there is a preference for noninvasive techniques for reasons of convenience, ease of use, and patient comfort. In this article, recent data that support the use of exhaled nitric oxide as a noninvasive biomarker of inflammation in clinical practice are reviewed.