Exhaled carbon monoxide as a new marker of respiratory diseases in children.

Among modern methods included in diagnostic algorithms for various diseases, analyses of expired breath and its condensate acquire increasing importance. Various markers can be determined in the exhaled air, especially volatile gaseous compounds: nitrogen oxide (NO), carbon monoxide (CO), hydrocarbons and 8-isoprostanes. In contrast to NO, CO can serve as a marker of inflammation and oxidation stress. The representation of CO in the exhaled breath (eCO) changes in various diseases of the respiratory and other systems. Among the respiratory diseases in which the use of eCO measurement seems to be perspective and beneficial are bronchial asthma, airways infections, cystic fibrosis, and primary ciliary dyskinesia. The observation of eCO concentrations represents a modern, simple, available, and well reproducible method for the diagnosis of many diseases of respiratory system in children and for the observation of progression, severity of the disease, and response to therapy.