Autoinhalation of nitric oxide after endogenous synthesis in nasopharynx

Lancet. 1994 Feb 26;343(8896):518-9. doi: 10.1016/s0140-6736(94)91465-6.


Exogenous nitric oxide (NO) reduces pulmonary vascular resistance after low-dose inhalation in patients. To estimate endogenous NO synthesis in the upper respiratory tract, we measured inhaled and exhaled NO in volunteers and patients during spontaneous or controlled ventilation, respectively. 20.3 nmol per min NO was synthesised in the nasopharynx of non-smoking volunteers, leading to autoinhalation of 0.07-0.13 NO parts per million during inspiration; smokers had reduced NO synthesis. In volunteers, 50-70% of the NO was resorbed by the lungs; ventilated patients were deprived of NO autoinhalation. Bacteria in the nose may take part in endogenous NO synthesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Breath Tests
  • Feedback
  • Female
  • Humans
  • Inhalation*
  • Male
  • Middle Aged
  • Nasopharynx / metabolism*
  • Nitric Oxide / biosynthesis*
  • Respiration, Artificial
  • Smoking / adverse effects
  • Vascular Resistance
  • Ventilation-Perfusion Ratio


  • Nitric Oxide