Differential transnasal pressure in anterior and posterior rhinomanometry.

Transnasal differential pressures during spontaneous breathing through an artificial nasal model were measured using anterior and posterior types of rhinomanometry by Rhinorheograph MPR-1100 manufactured by Nihon Kohden Co., Ltd. for comparing postnasal pressures at the nasopharynx with those at the nostril. No significant differences between postnasal pressures at the nasopharynx and at the nostril were found at 0.25, 0.5 liter/s, or the peak flow point on the pressure/flow relation curve. Application of the Ohm's Law equation for parallel resistors to nasal airflow resistance seems to be a more important problem than the differences resulting from the postnasal pressure sampling procedures in the anterior and posterior methods.