A functional tool to differentiate nasal valve collapse from other causes of nasal obstruction: the FRIED test.

Nasal valve collapse is a dynamic abnormality that is currently diagnosed purely on the basis of clinical features and thus subject to certain interpretation. The aim of this study was to develop a new and reliable functional test to objectively characterize nasal valve collapse. This was an observational prospective study including consecutive patients referred to our center for exploration of chronic nasal congestion. The patients were classified into two groups according to their symptoms and clinical abnormalities: the nasal valve collapse (NV+) group when nasal valve collapse was clinically detected during moderate forced inspiration and/or when the feeling of nasal congestion improved during passive nasal lateral cartilage abduction (n = 32); and the no-nasal valve collapse (NV-) group for the others (n = 23). All patients underwent nasal functional tests (posterior rhinomanometry and acoustic rhinometry) before and after topical nasal decongestion. We compared the difference between the pressure flow of the inspiratory and expiratory phases during posterior rhinomanometry [flow rate inspiratory-expiratory difference (FRIED) test] between the two groups. The difference between the absolute value of inspiratory and expiratory flow was significantly higher in the NV+ group than in the NV- group both before and after topical decongestion. The cutoff value for the FRIED test was -0.008 l/s with a good sensitivity (82%) and a specificity of 59%. We suggest that the FRIED test constitutes an objective and easy-to-apply technique to diagnose nasal valve collapse in daily practice.