Nasal sensation of airflow following blockade of the nasal trigeminal afferents.

A matched-pair parallel, group trial was carried out on 2 groups of 13 subjects (26 subjects in total), using 2% aqueous lignocaine to anaesthetize both the nasal vestibule and the nasal mucous membrane. Both groups had lignocaine infiltrated into the nasal vestibule and lignocaine applied topically to the nasal mucous membrane. The groups differed in the order in which the medication was given, one group having the infiltration first and the other group the topical application first. Local anaesthesia of the nasal vestibule caused a marked decrease in the nasal sensation of airflow (P less than 0.05) with no accompanying change in nasal resistance to airflow. Topical anaesthesia of the nasal mucous membrane had no effect on either nasal sensation of airflow or nasal resistance. The study demonstrates that the nasal vestibule is the dominant area for sensing nasal airflow. The nasal cavum (the major part of the nasal cavities that is lined by respiratory mucosa) appears to be unimportant as regards the sensation of nasal airflow. The clinical significance of the study is discussed with reference to other work, in this field.