Nasal nitric oxide flux from the paranasal sinuses

Curr Opin Allergy Clin Immunol. 2023 Feb 1;23(1):22-28. doi: 10.1097/ACI.0000000000000871. Epub 2022 Nov 9.


Purpose of review: Upper airway nitric oxide (NO) is physiologically important in airway regulation and defense, and can be modulated by various airway inflammatory conditions, including allergic rhinitis and chronic rhinosinusitis - with and without polyposis. Paranasal sinuses serve as a NO 'reservoir', with concentrations typically exceeding those measured in lower airway (fractional exhaled NO or FeNO) by a few orders of magnitude. However, the dynamics of NO flux between the paranasal sinuses and main nasal airway, which are critical to respiratory NO emission, are poorly understood.

Recent findings: Historically, NO emissions were thought to be contributed mostly by the maxillary sinuses (the largest sinuses) and active air movement (convection). However, recent anatomically-accurate computational modeling studies based on patients' CT scans showed that the ethmoid sinuses and diffusive transport dominate the process.

Summary: These new findings may have a substantial impact on our view of nasal NO emission mechanisms and sinus physiopathology in general.

Publication types

  • Review
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Humans
  • Nasal Polyps*
  • Nitric Oxide
  • Paranasal Sinuses* / diagnostic imaging
  • Rhinitis, Allergic*
  • Sinusitis*


  • Nitric Oxide