In both groups, the patients were managed to achieve predefined standard goals, i.e. a meen arterial pressure (MAP) >80 mmHg and an urine output > 0.5ml/kg/h. The patients of the “protocol group” (Group A) were managed to keep O2ER below 26.7%, following algorithms detailed in figure 1. In brief, a fluid challenge (colloids 250-1000 ml infused over 30 min to restore central venous pressure to at least 10 mmHg), dobutamine (incremental doses of 3 µg/kg/min up to 15 µg/kg/min) and/or packed red cells (in cases of hemoglobin below 10 g/dl or intraoperative hemorrhage > 1000 ml) could be administered. There was no specific requirement regarding the type of anesthesia in any of the groups.