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Updated: Aug 22, 2025

A Novel Inhalation Mask System to Deliver High Concentrations of Nitric Oxide Gas in Spontaneously Breathing Subjects
Published on: May 4, 2021
Nasal nitric oxide flux from the paranasal sinuses
Barak M Spector1, Dennis J Shusterman2, Kai Zhao1
1Department of Otolaryngology - Head and Neck Surgery, The Ohio State University, Columbus, Ohio.
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.
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