Measurement and regulation of nasal airflow resistance in man.

A method for measuring human nasal airflow resistance (Rnaw) is described. Air flows at constant pressure through both nasal cavities via a face mask and out through the mouth. Airflow is inversely related to Rnaw. The method has several advantages over many other methods for measuring Rnaw, in particular allowing aerodynamic separation of nose and lungs, and frequent measurements over long periods without discomfort to or intervention with subjects or patients. We have used this method to obtain standard values of Rnaw in healthy subjects and in patients with asthma and/or rhinitis. Age has a negative correlation with Rnaw but no sexual difference was seen. Cigarette smoking increases Rnaw especially in young adults. Patients with rhinopathy have much higher resistances than healthy subjects, but those with asthma alone do not. Rnaw is sensitive to changes in ventilation and lung volumes; deep inspiration and oral hyperventilation decrease Rnaw, while deep expiration, nasal hyperventilation and breath-holding increase it. Hypoxia and hypercapnia locally applied in the nose increase Rnaw. It is suggested that these changes are predominantly due to changes in control of the nasal vascular bed.