NITRIC-OXIDE IN EXHALED AIR

Much interest is now being focused on measurements of nitric oxide (NO ) in exhaled air, In healthy subjects exhaled NO seems to originate ma inly in the nasal airways, whereas the contribution from the lower res piratory tract is low. In certain inflammatory airway disorders, the e xcretion of NO into the airways is altered resulting in changes in the levels of NO in exhaled air. New techniques have been developed to me asure NO release at different levels of the airways: asthmatics show i ncreased orally-exhaled NO levels, whereas patients with cystic fibros is or Kartagener's syndrome exhibit a marked reduction in nasal releas e of NO. It has been suggested that measurements of exhaled NO may be clinically useful in noninvasive diagnosis and monitoring of inflammat ory airway diseases. To further evaluate the potential clinical useful ness of measurement of exhaled NO, it is vital to explore how airway N O production is normally regulated and what factors influence airway N O excretion.