The role of mucosal receptors in the nasal sensation of airflow

Abstract

50 subjects were admitted into a randomized double-blind placebo controlled cross-over trial with 4% lignocaine as the active drug and normal saline as the placebo. Each subject had 2 ml of solution sprayed into each nasal cavity and all subjects had both sprays but on different occasions. The order in which the sprays were administered was randomized. The subjective sensation of nasal airflow was measured using a visual analogue scale before and after the spray. These measurements were made under conditions of the same airflow rate, which was monitored throughout the experiment using a reprogrammed NR6 rhinomanometer. Objective nasal patency was measured as peak nasal inspiratory flow rate. It was found that the nasal sensation of airflow decreased slightly after both lignocaine (difference between medians 5.0; 95% confidence interval -2.91 to 6.11) and normal saline (difference between medians 6.0; 95% confidence interval -1.02 to 7.21). Nonparametric analysis of variance showed this difference to be non-significant (P = 0.73). In addition there was no significant change in objective nasal patency. The results suggest that nerve endings in the nasal mucosa play no part in sensing nasal airflow during respiration.