Fractional exhaled nitric oxide (FeNO) is a convenient, non-invasive method for the assessment of active, mainly Th2-driven, airway inflammation, which is sensitive to treatment with standard anti-inflammatory therapy. Consequently, FeNO serves as a valued tool to aid diagnosis and monitoring in several asthma phenotypes. More recently, FeNO has been evaluated in several other respiratory, infectious, and/or immunological conditions. In this short review, we provide an overview of several clinical studies and discuss the status of potential applications of NO measurements in clinical conditions beyond asthma.
Keywords: COPD; allergic rhinitis; allograft rejections; bronchopulmonary dysplasia; cystic fibrosis; exhaled nitric oxide; hepatopulmonary syndrome; pulmonary hypertension; respiratory infections; scleroderma.