[Correlation between the concentration of plasma lactic acid and other cardiorespiratory parameters in hypoxic...

We carried out a study in a group of 20 patients; this group was made up of 16 women and 4 men. All patients were under controlled ventilation and the relation between partial pressure of oxygen and the fraction of oxygen to be inhaled was equal or less than 150. A Swan-Ganz catheter was implanted in the pulmonary artery and another catheter in a radial artery. We determined the cardiac output, oxygen saturation in mixed venous blood and blood levels of lactic acid. We calculated the oxygen supply, oxygen consumption and tissue extraction of oxygen. We could to point out that there is a positive and significative correlation between lactic acid blood levels and cardiac output, oxygen consumption and oxygen extraction (p less than 0.001); negative and significative between acid blood levels and oxygen supply (p less than 0.025) and oxygen saturation in mixed venous blood (p less than 0.001). Finally we observed that when the lactic acid blood levels went up, decrease in oxygen saturation in mixed venous blood is more acute that increase in cardiac output.