 Current technique of continuous monitoring of lactate using Eirus system has a potential to broaden our knowledge in this clinical scenario and reinforce a decision-making in high-risk cardiac surgery. Hence, continuous measurement of lactate may be a valuable adjunct to routine hemodynamic parameters and blood gases, facilitating changes in fluid therapy and inotropevasopressor support for the achievement an adequate balance between oxygen demand and delivery. Combination of continuously measured lactate with monitoring of cardiac output, mixed and central venous saturation and Pv-aCO2 seems to be an attractive approach to global view on the systemic oxygen transport at the bedside. Recently, the continuous monitoring of lactate has been validated in a pilot clinical study in cardiosurgical patients mostly with isolated CABG and aortic valve replacement with relatively short-term CPB, however its role in combined cardiac surgery with prolonged CPB, representing the important setting for lactate-guided therapy, remains unsettled. 