Evidence for correlation of objective and subjective measures of nasal airflow in patients with common cold

Objectives: To utilize posterior rhinomanometry and conductance, as units of measurement, to further investigate the relationship between subjective and objective measures of nasal airflow. Design: A prospective, observational study. Setting: Common Cold Research Centre. Participants: Sixty healthy volunteers from the staff and student population of Cardiff University with an upper respiratory tract infection. Main outcomes measures: To determine correlations between visual analogue scores (VAS) and posterior rhinomanometry for total, unilateral, high and low conductance groups. Results: No correlation was found between total VAS and total conductance (r = 0.17, P = 0.10). A substantially significant correlation was found between unilateral VAS and unilateral conductance (ρ = 0.50, P < 0.001). The unilateral VAS and conductance were highly correlated for the low total conductance group (ρ = 0.61, P < 0.001). Conclusions: Posterior rhinomanometry allows actual measurement of the combined and unilateral conductance of nasal passages. The units of conductance, as opposed to resistance, allow totally obstructed nasal passages to be included in analysis. Visual analogue scores and conductance correlate strongly in unilateral measures for participants with a low total nasal conductance. Posterior rhinomanometry and units of conductance are recommended for future studies investigating the relationship between objective and subjective measures of nasal airflow