Removing nasal valve obstruction in peak nasal inspiratory flow measurement

Background: Peak nasal inspiratory flow (PNIF) measurements are used to evaluate nasal obstruction and as a surrogate for disease activity in allergic rhinitis and other nasal complaints. This measurement can give erroneous results when forced inspiration leads to nasal valve collapse. Objective: To determine the effects of 2 different nasal stents (Sinuscone and Nozovent) on valve collapse and repeatability of PNIF measurements. Methods: Repeated measurements of PNIF were obtained in 74 individuals with and without 2 different nasal stents: Sinuscone and Nozovent. Results: The mean (95% confidence interval) improvernent in PNIF was 1.7 L/min (-2.4 to 5.8 L/min; P = .42) with Nozovents and 25.4 L/min (11.4 to 39.4 L/min; P = .001) with Sinuscones. The PNIF coefficient of variation for repeatability was 11.6% without stents, 16.0% using Nozovents, and 10.4% using Sinuscones. Conclusions: Sinuscones, but not Nozovents, significantly improved PNIF. Repeatability of PNIF measurements was worse with Nozovents and only marginally improved with Sinuscones.