Presence of ~3000 known different compounds in human exhaled breath are reported concentrations their are changing in different diseases and can be used as biomarkers. This review (consisting of 58 papers) focused on the available knowledge on exhaled biomarkers mainly nitric oxide, hydrogen peroxide, aldehydes and hydrocarbons. Nitric oxide has been used in many pulmonary inflammatory diseases including asthma, chronic obstructive pulmonary disease (COPD), diagnosis of atopic asthma and chronic cough as well as monitoring is of corticosteroid therapy. Hydrogen peroxide is increased in asthma, acute respiratory distress syndrome, cystic fibrosis, COPD, lung cancer and also in systematic disease such as breast cancer and rhumatic arthritis. Exhaled aldehydes is monitoring also useful for the oxidative stress. An inverse correlation was observed between malondialdehyde and FEV1. Hydrocarbons, such as benzene and toluene, are increasing in lung cancer, cardiac transplant rejection, asthma, rhumatic arthritis, acute myocardial infarction and schisophrenia. Monitoring of exhaled biomarkers is a non-invasie, repeatable, real time measurment and applicable to children. Therefore, investigations on exhaled biomarkers have attracted more attention in respiratory medicine, and development of sensitive and specific analytical methods is highly demanding.
Keywords: Exhaled biomarkers, Nitric oxide, Hydrogen peroxide, Aldehydes, Hydrocarbons, Pulmonary diseases