Peripheral airways obstruction in patients with rhinitis.

Nine young lifetime nonsmoking patients with symptoms of rhinitis but without any history of asthma or wheezing and nine age-matched healthy lifetime nonsmoking control subjects were studied with respect to subdivisions of lung volume, forced vital capacity, forced expiratory volume (1.0 sec), and flow-volume curves breathing air, and also breathing a mixture of 80% helium--20% oxygen (He-O2) from which were obtained airflows at 50% VC (Vmax50), the percentage increase in Vmax50 breathing He-O2 as compared to air (deltaVmax50) and the point where He-O2 and airflow-volume curves became identical (Visov). No significant differences between the two groups in age, subdivisions of lung volume or forced expiratory airflow rates were recorded. However, deltaVmax50 was significantly lower in the patients (16.4 +/- 12.0) compared to the controls (47.7 +/- 16.4) (p less than .001) and Visov was higher in the patients (28.4 +/- 14.9) as compared to the controls (14.4 +/- 7.6) (p less than .01). After bronchodilator therapy Vmax50 increased in the control subjects (p less than .005) but not in the patients and deltaVmax 50 decreased in the control group but was unchanged in the rhinitis patients. These results suggest that patients with rhinitis who have normal airflow rates may have peripheral airways obstruction not readily reversible with bronchodilators.