Evaluation of nasal resistance data in active anterior rhinomanometry with special reference to clinical usefulness and test-retest analysis.

A systematic evaluation of the most common parameters used in active anterior rhinomanometry was made with artificial tube and cadaver models and patient recordings. The clinical suitability of the parameters was judged on their calculability, reproducibility and power to separate the recordings into meaningful degrees of patency. It was shown that resistance at 150 Pa was not calculable in 30% of the measurements because such a high pressure gradient was not achieved during quiet breathing. The power to separate the grades of obstruction was good with all the models but in the test-retest analysis, it was shown that the power to detect +/- 20% variation in repeated measurement in the same person with a decongested nose was not sufficient with the resistance at 150 ml/s and at radius 100. The coefficient of resistance W = P/V2 at peak flow and resistance at radius 200 showed good capability to separate the grades of obstruction, they are measurable in all recordings, their reproducibility is good and thus, they are recommended for clinical practice.