A comparison of current expressions of nasal patency

Rhinomanometry is well established as a useful clinical method for objective assessment of nasal patency, although several expressions of nasal patency have been reported and universal standardization has not been achieved. In this communication, nasal resistances were calculated from the equation R = delta P/V (R; resistance; delta P; transnasal differential pressure; V; nasal airflow) at delta P 100 Pa and at peak flow. Time-averaged nasal resistances and integrated nasal patencies were measured in 350 adult patients by Rhinorheograph MPR-1100 and processed by a NI-101 computer program. The values from the equation R = delta P/V at delta P 100 Pa were slightly lower than those from the same equation at peak flow or those from the time-averaging method. Correlations between the values of nasal resistance at peak flow and the time averaging method were very close to the line of identity. No significant correlations were demonstrated between integrated nasal patency and the values from the other three expressions. The differences of the results from these expression are discussed.