Background: Paranasal sinuses are reservoirs for nitric oxide (NO), and humming facilitates nasal diffusion of NO. The nasal NO response to humming has previously been shown to be blunted with chronic sinusitis and nasal polyposis. We hypothesized that the nasal NO response to humming will be proportional to radiographic osteomeatal patency when comparing allergic rhinitis (AR) patients (without chronic sinusitis) with normal controls.
Methods: Nonsmoking subjects completed questionnaires and skin-prick testing. Subjects underwent sinus CT scanning, followed by exhaled (oral) and nasal NO sampling (with and without humming). Humming-to-quiet (H/Q) nasal NO ratios were calculated. Three-dimensional reconstructions were used to trace the osteomeatal complex (OMC) and measure minimum cross-sectional area. Lund-Mackay scores were also documented.
Results: A total of 33 subjects (22 women; mean age, 35.5 years) completed the study. Seventeen AR patients (5 IAR and 12 PAR) participated, as did 16 nonallergic controls. Among controls, quiet nasal NO levels--corrected for fractional exhaled NO--rose significantly with OMC area and fell significantly with Lund-Mackay scores (p < 0.05). However, we observed no proportionality between H/Q ratio and radiographic OMC patency.
Conclusion: Analysis of nasal NO samples taken under quiet conditions from normal controls was consistent with the paranasal sinuses acting as a reservoir of nasal NO and with OMC patency acting as a significant factor in NO diffusion. However, our results did not support a relationship between the nasal NO response to humming and radiographic OMC patency in a sample excluding subjects with severe rhinosinusitis.