[Steady-state carbon monoxide transfer during progressive muscular exercise in patients. Relation to PaO2. Value of specific VCO]. / Le transfert du monoxyde de carbone en "état stable" lors de l'exercice musculaire progressif chez le malade. Relations avec PaO2. Intérêt de VCO spécifique.

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)

[Pulmonary carbon monoxide exchange constants in the "stable state" at rest in healthy non-smokers]. / Constantes d'échange pulmonaire du monoxyde de carbone en "état stable" de repos chez le sujet sain non fumeur.

During simultaneous evaluation of pulmonary O2, CO2, and CO in the stable state (ES) at rest, CO volume per minute (V'CO) standardized (V'COs) for FICO = 0.001 [2, 3] can be expressed relative to simultaneous flow of "respiratory" gases (V'O2 and V'CO2) by the quotient of the gas concentrations concerned, if its is admitted that V'I = V'E. Whether at the "expired"mean E or "alveolar" A levels, these concentrations have identical paired relationships. In the strict stable state, the proposed expressions of V'CO are constants independent of age, sex, stature, and ventilatory regimen in healthy non-smokers [6]; the result is that V'COs in relation to alveolar ventilation, V'COs/V'A, which is related to V'COs/V'CO2 by PaCO2, is also a constant. When the so-called "stable" state is not a strict one, experimental arguments suggest that V'COs/V'CO2 alone is not markedly influenced by ventilatory instability. Measurements conducted by means of different biological modalities and techniques in 3 groups of healthy women of homogeneous age breathing in a semi-open circuit: 1) established the value of the constants V'COs/V'CO2, V'COs/V'O2, V'COs/V'A in the true stable state (ESV) controlled by R and by gasometry on simultaneously collected blood samples; and 2) confirmed the constant character of V'COs/V'CO2 whatever the degree of respiratory stabilization, even when the ventilatory regimen was in reality not stabilised (ENS); V'COs/V'CO2 should therefore be the only value for defining a "specific capacity of pulmonary CO exchange". V'COs/V'A appears to be related to Q'/V'A. As DuCO/(DuCO2.1,21), which measures this ratio, it is independent of age and of ventilatory frequency. Several facts indicate that the "parallelism" of modifications affecting DuCO and DuCO2 [15] is not found in all physiological and pathological circumstances.