Unilateral and bilateral nasal resistances: a supplement.

Three hundred and thirty-four measurements of bilateral and unilateral nasal resistance (at delta P 1.0 cm H2O and by time averaging) in 233 adults were carried out by posterior rhinomanometry with a head-out body plethysmograph. Total nasal resistances, calculated by the equation of Ohm's Law for parallel resistors from measured unilateral resistances, were compared with measured total nasal resistances. The time averaged total nasal resistances calculated by use of Ohm's Law for parallel resistors were closer to direct measurements than resistances at delta P 1.0 cm H2O calculated from the same equation. We attempted to fit calculated total nasal resistance with direct measurements by modification of the equation of Ohm's Law for parallel resistors to T = 0.96[R x L/(R + L)]0.92 in the time averaged nasal resistance and T = 1.07[R x L/(R + L)]0.77 in resistance at delta P 1.0 cm H2O (T: total nasal resistance, R: nasal resistance on the right side, L: nasal resistance on the left side). Calculated total nasal resistances from the above equations agreed closely with direct measurements.