Overview The Effect of Nasal Carbon Dioxide (CO2) on Nasal Congestion in Subjects With Perennial Allergic Rhinitis Status: Completed Trial end date: 2008-07-01 Target enrollment: Participant gender: Summary The purpose of this study is to evaluate the effect of nasal CO2 on nasal congestion and other symptoms related to Perennial Allergic Rhinitis. Phase: Phase 2 Details Lead Sponsor: Capnia, Inc.