Anterior and posterior rhinomanometry

Three rhinomanometric techniques for detection of transnasal pressures were compared by computer aided plethysmographic rhinomanometry. Mean unilateral resistances were measured in the decongested nose of an experienced subject by traditional anterior (sealed anterior catheter) and posterior (perorally by mouthpiece) rhinomanometry and also by a fine catheter inserted pernasally to the nasopharynx. No significant differences in magnitude (N = 25, p = 73, mean Rn = 0.345 Pa/cm3/sec) were found. Dimensions of an #8F catheter were adequate for conduction of transnasal pressures and the catheter placed along the floor of a decongested nasal cavity was found not to increase resistance to airflow significantly. Posterior pernasal catheter measurements were less variable than either traditional posterior (peroral) or anterior rhinomanometry. In 35 consecutive patients untreated by decongestant there were no significant differences in magnitude or variation between resistances of the combined nasal cavities immediately following insertion of the catheter and those obtained 5 minutes later (initial mean Rn = 1.66 + 0.49, 5 min mean Rn = 1.70 + 0.50) and in these naive subjects posterior rhinomanometric resistances averaged 9% greater than those in whom resistances were measured pernasally.