Measurements of Nasal Fractional Exhaled Nitric Oxide with a Hand-held Device in Patients with Allergic Rhinitis: Relation to Cedar Pollen Dispersion and Laser Surgery

Background: There has been an increasing interest in monitoring the fractional concentrations of exhaled NO (FeNO) levels in allergic rhinitis (AR) patients. In the present study, we examined whether the nasal FeNO measurement might reflect the degree of local allergic inflammation as well as subjective symptoms. Methods: The FeNO measurement was performed using a handheld electrochemical analyzer (NObreath®) with a nose adaptor. In the cross-sectional study, 56 patients with perennial AR patients, 18 AR patients with bronchial asthma (BA), 12 patients with vasomotor rhinitis, and 30 normal subjects were enrolled. For the follow-up study, 12 seasonal allergic rhinitis (SAR) patients against Japanese cedar and 10 perennial AR patients who underwent laser surgery were examined. Results: The AR patients and vasomotor rhinitis patients showed significantly higher oral FeNO levels as compared with the normal subjects. The nasal FeNO levels were significantly higher in the perennial AR patients with or without BA than in the normal subjects and vasomotor rhinitis patients. There were positive correlations between the nasal symptom scores and FeNO levels. The SAR patients showed a significant decrease in the nasal FeNO level after the pollen dispersion season. In addition, the therapeutic effects of laser surgery in the AR patients accompanied a significant reduction in the nasal FeNO levels one month after treatment. Conclusions: The nasal FeNO measurement by NObreath® is easy to perform and suitable for monitoring AR patients in various treatment modalities. Furthermore, it may have potential usefulness as a tool to improve daily clinical care