Objective: The aim of our work has been the study and comparison of diffusion capacity of CO (DLCO) in two different clinical situations: bronchial asthma and diabetes mellitus.
Method: We have studied 16 control subjects, 38 patients with bronchial asthma and 65 patients with diabetes mellitus. We performed CO pulmonary diffusion tests by single breath method to determine two components: membrane diffusion factor (Dm) and pulmonary capillary blood volume (Vc).
Results: We have found a positive correlation of FEV1 with Dm. The bronchial asthma group had a lower FEV1 and FEF25-75% and an increase in DLCO, Dm and Vc, with respect to the control group. The diabetes mellitus group presented a decrease in CVF, FEV1, DLCO and Vc, with respect to the control group. The bronchial asthma group showed a lower ratio of Dm/Vc than the control and diabetes groups.
Conclusions: The bronchial asthma patients have an increase in CO pulmonary diffusion, membrane diffusion factor and pulmonary capillary volume. However, the diabetes mellitus patients present a decrease in CO pulmonary diffusion mainly due to pulmonary capillary volume.