Computer-aided rhinometry: analysis of inspiratory and expiratory nasal pressure-flow curves in subjects with rhinitis.

Airflow through the nose was measured by posterior rhinometry with the aid of a microcomputer to study reproducibility of pressure-flow curves, the ease of detection of nasal congestion and decongestion, and mathematical modelling of P-V curves. In twelve subjects with rhinitis, the median coefficient of variation of nasal airway resistance was between 4.9% and 14.4% and was not significantly affected by inspiration and expiration, congestion and decongestion, or the flow rate at which it was measured. Fitting of 630 P-V curves to a quadratic equation was usually excellent, particularly during expiration.