METHODS: In this prospective study, we compared 25 patients with ECRS, 45 patients with non-ECRS, and 33 normal controls. The nasal NO levels were determined by subtracting the nasal FeNO level from the oral FeNO level, as measured using a nitric oxide analyzer. Correlation between nasal NO levels and clinical findings were observed. To evaluate the effect of endoscopic sinus surgery (ESS) on nasal NO levels in the patients with CRS, we measured nasal NO levels preoperatively and at 3 and 6 months postoperatively.
RESULTS: The nasal NO levels were significantly decreased in patients with CRS, but more so in those with ECRS; moreover, nasal NO levels in patients with CRS significantly and negatively correlated with eosinophil levels in both blood and in nasal polyp tissue, as well as with the computed tomography score. However, they did not correlate with the nasal polyp score.
CONCLUSIONS: Our results indicate that nasal NO may be useful as a marker of CRS severity and low nasal NO levels in patients with CRS might contribute to its pathogenesis, especially in the development of ECRS.