Normal nasal resistance.

Eighty normal adults without nasal symptoms were studied to determine normal nasal resistance values and the variation of nasal resistance in normal adults. A microprocessor-based system for collection and analysis of transnasal pressure and flow was used to obtain nasal resistance values. Unilateral and total transnasal pressure and flow values were determined before and after decongestion of the nose with 1% phenylephrine spray. The distribution of the 80 resistance values was found to be skewed to the right. Log transformation of the resistance values was the best method to normalize their distribution. The mean and variation of normal nasal resistance are reported at flows of 0.1 and 0.2 L/sec, at pressures of 0.5 and 1 cm H2O, and at radii of 1, 2, and 3 on the pressure-flow curve.