Quantitative assessment of dyspnea during exercise before and after bullectomy for giant bulla.

Incremental exercise testing using a cycle ergometer was performed in eight patients with giant bulla before and after bullectomy to assess dyspnea. There was a significant positive linear relationship between dyspnea expressed in the Borg scale (BS) and oxygen consumption (VO2) during exercise in all subjects. From these correlations, we introduced the following three new parameters for quantitative assessment of dyspnea: the Borg scale slope (BSS); the threshold load of dyspnea (TLD); and the breakpoint load of dyspnea (BLD), representing the slope of the regression line, onset of dyspnea on the regression line, and the maximum oxygen consumption before the subjects interrupted exercise, respectively. After surgery, the BSS showed marked decrease, and the TLD and BLD showed significant increase. Therefore, the reduction in the dyspnea with peak exercise after surgery was thought to be, at least in part, based on the delay of dyspnea onset, the decrease in dyspnea sensitivity, and the improvement in exercise capacity. The improvement in dyspnea during exercise in patients with giant bulla after surgery was extensively evaluated by newly introduced parameters based on BS-VO2 regression line.