[Diagnostic use of oxygen consumption and gas exchange in exercise testing]

The interpretation of cardio-pulmonary exercise testing is usually performed on successive decisional organigrams which are based on the normality of two initial main branchpoints i.e., Vo2max and ventilatory threshold (VThr). This didactic approach leads however to a simplistic approach of exercise pathophysiology because the answer to the two original branchpoints (Vo2max and VThr) is mainly binary whereas the physiological meaning of these two parameters is multifactorial. Thus, we propose a methodic analytical approach which allows to integrate step by step the various informations concerning aerobic capacity, ventilatory and cardiocirculatory responses, and acidobasic status. After a purely descriptive analysis of data , a first synthesis describes the physiopathological behaviour during exercise and states the specificity of these informations excluding usual confounding factors. The comparison between the functional data and the clinical informations allows to propose some physiopathological hypothesis by confronting several complementary approaches: physiological, physiopathological and clinical ones. This method seems to be more adapted to the clinical diagnostic use of such a physiological investigation because it is sensitive, reproducible but not specific.