Exhaled carbon monoxide in childhood asthma

Objectives: Oxidative stress and inflammation induce the expression of heme oxygenase-l, which produces carbon monoxide (CO), and nitric oxide synthase, which produces nitric oxide (NO). Exhaled CO and NO levels are elevated in asthmatic patients and are decreased after corticosteroid treatment, suggesting that they may be useful as noninvasive markers of airway inflammation.