Measurement of the cardiac output in man

Abstract

CHRISTIANSEN et al. [1914] described a method for determining the gas contents and gas pressures of the mixed venous blood entering the lungs and deduced the rate of blood flow through the lungs. (1) that the correction applied for the increase of oxygen consumption caused by the deep breathing during the experimental period was large and very variable, and (2) that the rate of blood flow through the lungs might be diminished appreciably during the period of measurement while the breath was held.Modifications of the foreign gas method have been used extensively, and the suitability of such gases as ethyl iodide, ethylene and acetylene has been investigated. The most successful of these methods has proved to be the acetylene method of Grollman [1929, 1932], which has been generally adopted. The results obtained by this method are very constant for a given individual under basal conditions, and have been found by Christensen [1931]

The solubility of acetylene in blood

“…THE acetylene method for determination of cardiac output seems to give very constant figures for a given individual under basal conditions, and the results obtained with Grollman's method seem also in most cases to agree well with the results obtained by methods based on Fick's principle [Grollman, 1932;Cooke & Priestley, 1937]. The use of the acetylene procedure in cases of heart failure in man, however, is based on the assumption that the solubility coefficient of acetylene in the blood of such cases is exactly known, and that the acetylene pressure found in the air of the rebreathing system agrees very accurately with the acetylene pressure of the arterial blood itself.…”