Nitric oxide (NO) is produced in high concentration in the upper respiratory tract. The high concentration of NO is toxic to bacteria and viruses and thus helps to defend the mucous membranes of upper respiratory tract.
In recent years is an increasing worldwide interest in the measurement of nasal nitric oxide (nNO) in diseases of the upper respiratory tract. In the literature, are starting to publish work about the measurement of nasal nitric oxide in ciliary dyskinesia, adenoid vegetation, allergic rhinitis or acute and chronic rhinosinusitis.
The measurement of nasal nitric oxide in otorhinolaryngology is based only on several experimental studies yet. More clinical data are necessary to consider a true impact for clinical treatment.