Relation between Selective Alveolo-bronchography and Small Airway Function Tests

Abstract

To evaluate the validity of scoring method of small airway function tests, selective alveolobronchography (SAB) was performed on 7 patients with bronchial asthma, 7 patients with chronic pulmonary emphysema and a patient with chronic bronchitis. The small airway lesion observed on SAB film was compared with the pulmonary function data including closing volume (CV), ΔN₂/L, volume of isoflow (Visov) and ΔV₅₀ and further with total score of the abnormalities in CV, ΔN₂, Visov, and ΔV₅₀ (SAO score).
The severity of small airway lesion in SAB was expressed as the mean of maximum diameter/minimum diameter ratioes (ratio of bronchial diameter, RBD) in each 1cm-long segment on magnified film (3 to 4 fold).
1. Significant but loose correlation was found between FEV_1.0% and RBD, but correlation was not significant between respiratory resistance and RBD.
2. Among small airway parameters, only CV was significantly correlated with RBD.
3. Significant correlation was found between SAO score and RBD.
We conclude that the scoring method of small airway function tests is meaningfull for evaluation of small airway obstruction.