[Measurement of cardiac output by CO2 rebreathing technique. A study of reproducibility in the normal subject; application to cardiac insufficiency].

A feasibility and reproducibility study of cardiac output measurement by CO2 rebreathing was performed in normal subjects and in patients with compensated cardiac failure. The measurements were performed at rest and at the second stage of the Bruce protocol in normal subjects (N = 12) with a good reproducibility (r = 0.81) after an interval of two days. In patients with stable cardiac failure (N = 17), the cardiac outputs were 9.4 +/- 3.9 l/min and 9.3 +/- 3.1 l/min by measuring the arterial pCO2 and end-expiratory CO2 compared with the theoretical value of 9.9 +/- 2 l/min. The non-invasive measurement of cardiac output by the CO2 rebreathing method was well tolerated by patients and is reliable and reproducible.