Reliable and reproducible anterior active rhinomanometry for the assessment of unilateral nasal resistance.

Unilateral nasal resistance is now thought to be more important than total resistance in promoting obstructive symptoms. We assessed the reproducibility of anterior active rhinomanometry in measuring unilateral nasal resistance. Ten baseline readings of unilateral nasal resistance were made over a 30-min period in seven healthy subjects (14 nostrils) using anterior active rhinomanometry performed according to the International Committee for the Standardization of Rhinomanometry (ICSR) guidelines. Baseline readings revealed that measurements using anterior active rhinomanometry had an unacceptably high coefficient of variation (19%-60%). With a more time-consuming revised protocol involving multiple recordings and the identification and exclusion of erroneous data, coefficients of variation of 7%-15% were obtained. We conclude that single anterior active rhinomanometry readings are potentially prone to large errors and each researcher using such equipment must satisfy his/herself that their methodology has an acceptable coefficient of variation in their hands. The ICSR guidelines are not always sufficient to allow reproducible measurement and specially designed protocols may be necessary to produce reliable results.