[Quantitative assessment of dyspnea by introducing new indices based on the Borg scale during exercise test and the...

Incremental exercise test with a bicycle ergometer was performed on thirty eight patients (11 patients with chronic obstructive pulmonary disease, 6 patients with interstitial lung disease, 21 patients with preoperative check up for respiratory disease). In 34 patients except four patients with interstitial lung disease, there was a close correlation between dyspnea expressed on the Borg scale (BS) and oxygen consumption (VO2) (r = 0.778-0.998). To evaluate dyspnea in more quantitative manner, we introduced three parameters by the BS-VO2 regression line. The Borg scale slope (BSS) represents the slope of the regression line, threshold load of dyspnea (TLD) represents the onset of dyspnea on the regression line, and the breakpoint load of dyspnea (BLD) represents the maximum oxygen consumption before the subject interrupted exercise. BSS had significant negative correlations with VC, %VC, FEV1.0, TLC, DLco, and %DLco. TLD and BLD had significant positive correlations with VC, FEV1.0, DLco, and %DLco. No correlation was found between dyspnea evaluated by the Hugh-Jones classification and the parameters of pulmonary functions (VC, FEV1.0, DLco) at rest. From these findings, we conclude that the degree of dyspnea sensation on exercise correlated with parameters of pulmonary function at rest, and that these newly introduced parameters using the Borg scale were useful for a quantitative assessment of dyspnea in health and disease.