Inspiratory and Expiratory Effects of Nasal Breathing

Abstract

The purpose of the present study was to assess quantitatively the nasal valve area during normal inspiratory and expiratory maneuvers. The pressure-flow technique of Warren was used to estimate nasal size in 15 adult subjects who had no previous history of nasal surgery or abnormality. Cross-sectional size of the nasal airway was also assessed (1) after insertion of tubing to eliminate alar effects, (2) after administration of 0.1 % Otrivin decongestant to eliminate mucosal effects, and (3) by blocking each nostril individually. Mean areas were 0.63 cm2 i 0.17 during inspiration and 0.56 cm2-_I 0.14 during expiration. This difference is statistically significant (< 0.01) and the effect was maintained under conditions of occlusion of either nostril, insertion of tubing , and administration of Otrivin. These findings suggest that the nasal valve acts as a respiratory brake during expiration possibly to allow adequate time for gas exchange at the alveoli.