Exhaled nitric oxide as an indicator of severity of asthmatic inflammation

Traditional assessment of severity of asthma relies on an evaluation of sig ns and symptoms and pulmonary function tests. These pulmonary function test s, such as peak expiratory how rates, forced vital capacity, and forced exp iratory dow rates, are indirect measures of airway caliber only, and not in flammation, Since asthma is an inflammatory disease, a measure of the degre e of inflammation would be helpful in quantitating severity and titrating o f anti-inflammatory therapy. A noninvasive method for measuring pulmonary i nflammation would therefore be helpful to assist the emergency physician in initial treatment and assist in titration of anti-inflammatory therapy dur ing repeat visits. Exhaled nitric oxide (NO) assays are convenient and prac tical and may fulfill this cole. In this review we discuss the role of NO i n asthmatic inflammation and the role that exhaled NO values may play in th e emergency management of asthma.