Razi Journal of Medical Sciences

Spirometry and flow - volume loop show the abnormal pattern of pulmonary dysfunction and the site of the obstruction of upper and peripheral airways.

For determinig the shape of flow - volume loop in obstruction of carina and bronchus we examined 19 patients with large airway obstruction documented with fiberoptic bronchoscopy via pulmonary function testing and flow ­volume loop performing. Two patients a bout 70% obstruction of carina had F-V loop compatible with upper aiway obstrucion. 10 patients with obstruction of right or left main or intermedius bronchus had PFT criteria of restrictive pulmonary dysfunction but no change in F-V loop. In seven patients with lobar bronchus obstruction this obstruction did not change the shape of flow - volume loop. We reached to the conclusion that F-V loop in obstruction of carina is the same as fixed upper airway obstruction but obstruction in main and intermediate bronchuses show normal F-V loop with restrictive pattern, and obstruction of lobar bronchus dose not significantly change the shape of F-V loop or pulmonary function parameters.