243 Peak Inspiratory Flow Rate is More Sensitive Than Acoustic Rhinometry or Rhinomanometry in Detecting Nasal Obstruction Using the Allergen Challenge Chamber

BACKGROUND: We prepared an allergen challenge chamber (ACC) which facilitates quantitative pollen challenge at any time, and, so, the acquisition of objective data. The aim of this study was to evaluate peak nasal inspiratory flow rate (PIFR) as an endpoint during allergen challenge and compare this with rhinomanometry (Rhino) and acoustic rhinometry (AR). METHODS: The study was conducted in November, which is not in pollen season. Subjects were exposed to Japanese cedar pollen at a concentration of 50,000 counts/m3in ACC for 120 minutes each day for 2 days. Subject recorded nasal symptoms before challenge and every 15 minutes after challenge initiation. Nasal symptoms (sneezing frequency, nasal blowing frequency, nasal obstruction) were recorded before challenge and every 15 minutes after challenge initiation. For the evaluation of nasal obstruction, we used visual analog scales (VASs); subjects marked a site on a 10-cm line corresponding to the symptom severity on which absence of symptoms was designated as 0 and worst imaginable symptom as 10. PIFR was measured using an In-check flow meter and nasal resistance was measured using Rhino. The cross-sectional area in the nasal cavity was also measured using AR before and after challenge as an indicator of nasal obstruction. RESULTS: When the volunteers with cedar pollinosis were exposed to cedar pollen in ACC, pollinosis symptoms were induced significantly. Changes in the 3 symptoms (sneezing frequency, nose-blowing frequency, nasal obstruction) were investigated before and after challenges on 2 consecutive days. No significant symptoms were induced on the first day of challenge in the non-pollen season. However, each of the 3 symptoms became more severe with second day of challenge, and a significant increase was seen in cumulative values by the second day. In terms of the allergen challenge test, we found a significant correlation between nasal obstruction symptom (VAS) and PIFR, but not AR and Rhino. CONCLUSIONS: PIFR after allergen challenge is more sensitive than AR or Rhino in detecting nasal obstruction using the allergen challenge chamber.