The use of nasal spirometry for the assessment of unilateral nasal obstruction associated with changes in posture in healthy subjects and subjects with upper respiratory tract infection

Nasal spirometry was used to measure the effect of acute rhinitis associated with upper respiratory tract infection (URTI) on the changes in nasal airflow that occur with postural change. Results in 12 healthy subjects and 12 subjects with URTI were expressed as the nasal partitioning of airflow ratio (NPR), a new measure of nasal airflow. Values of NPR range from 0 (equality of airflow) to 1 (unilateral nasal obstruction). In subjects with URTI there was a significant change (P < 0.006) in the median NPR from 0.19 sitting to 0.87 supine, with five subjects having complete unilateral nasal obstruction. The change in the median NPR in the healthy subjects from 0.09 sitting to 0.13 supine was not significant. The results illustrate the incidence of complete unilateral nasal obstruction associated with URTI when lying flat and demonstrate the usefulness of nasal spirometry in studying nasal airflow partitioning in health and disease.