A fundamental study of rhinomanometry and its clinical application to objective evaluation.

We measured differential pressure and airflow at constant flow through a cylinder which had a variable aperture in its central portion, by means of a Rhinorheograph MPR-1100 in order to obtain a turbulent coefficient "n" experimentally in the equation R = delta P/Vn. Between of 1.0-5.0 cm H2O (not equal to 100-500 Pa) pressure, the coefficient "n" was distributed between 1.01-2.80 with a mean value of 2.02 (+/- 0.36), and resistances calculated from the equation R = delta P/Vn were almost the same value at each differential pressure. We applied this coefficient to 95 adult patients referred to our nasal airflow laboratory in Toronto, and found the equation R = delta P/V2 to be quite suitable for clinical assessment.