[Steady-state carbon monoxide transfer during progressive muscular exercise in patients. Relation to PaO2. Value of...

During muscular exercise, the alveolo-capillary gas exchange reaches its optimal capacity, but taking blood for arterial blood gases is associated with certain risks and the classical criteria of CO transfer in the steady state are difficult to interpret as they are influenced by age, sex, ventilatory regime. The "specific" CO uptake (VCO Sp) does not correspond to these criteria (6). When related to the ERCO2, it allows the DuCO to be determined (4). It has the same value at the 3rd minute and at the 10th minute of constant exercise (5). Like TCO, it is correlated with the PaO2 during effort (5). In this study, a triangular exercise was performed by men aged between 45 add 55 years, smokers and former smokers, classified into 4 A: 12 healthy subjects; B: 56 cases of chronic respiratory disease; C: 9 cases of chronic obstructive airways disease (COAD); D: 12 cases of diffuse pulmonary fibrosis (DPF). Groups C and D were derived from group B. The VCO SP, TCO and DuCO were measured at each plateau of the triangular exercise. In the patients, the PaO2 was measured at the same time as the FF (CO, CO2). In the last phase of exercise (Ex. Max.): VCO Sp was more frequently altered at rest and more strongly correlated to TCO; TCO/V had the same significance as DuCO. The results of TCO, VCO Sp and DuCO were compared between groups A, C and D.(ABSTRACT TRUNCATED AT 250 WORDS)