ABSTRACT
The correlation between the objective measurement of nasal resistance and nasal airflow sensation is usually regarded as poor. The aim of the study was to assess the relation between objective indices of nasal patency, as assessed by the occlusion method (RN) and the Youlten peak nasal inspiratory flow meter (PNIF), with subjective sensations of nasal blockade by either the patient or the clinician in groups of patients with rhinitis, asthma, rhinitis and asthma, nasal septal deformity and ill normal controls. We studied nasal airway patency in 254 subjects (37 women, 217 men), mean age 21 years (range 14-78) by RN and PNIF. Nasal resistance was also measured by the application of Ohm's law for parallel resistors (NRO) by estimating the unilateral resistance separately. Subjective sensation of nasal blockade was assessed either by the patient on a 10-point Borg scale (SUB), or the clinician (CLN) on a 6-point scale (3 for each side of the nose). The latter was done in a controlled fashion with the aid of reference sensations. Adjusting for age, height, smoking status and airway calibre, we found good correlation between RN and CLN (r=0.57, p=10(-4)), whereas the association between RN and SUB was moderate and of borderline significance (r=0.42. p=0.05). By logistic regression analysis, we found that the only independent predictors of abnormal nasal resistance at a cut-off value of 0.30 kPa/l/s were the nasal scores as assessed by the clinician (r-=0.26, odds=2.45). We conclude that PNIF measurement and SUB scores are of limited use as indices of nasal patency, although the latter showed an improved association in comparison to older studies. As there is a necessity for some sort of objective measurement to assess nasal patency, the described clinician evaluation may be clinically useful in place of PNIF, but due to its somewhat subjective nature and its inability to detect milder levels of nasal obstruction it cannot be recommended as an alternative to rhinomanometry.
