Objective To explore the effect of general anesthesia combined with thoracic epidural anesthesia and general anesthesia on intraoperative oxygen balance related index:central venous oxygen saturation (ScvO2), central venous-to-arterial difference of carbon dioxide (Pcv-aCO2) and difference between central venous and arterial lactate (Dcv-aLac) and postoperative complications in patients undergoing esophageal cancer surgery. Methods Sixty patients who received Ivor Lewis surgery were randomly divided into two groups: general anesthesia group (GA, n=30) and general anesthesia combined with thoracic epidural anesthesia (GE, n=30). The induction of general anesthesia was basically consistent,and the same depth of anesthesia was maintained in the two groups during the operation. Patient-controlled intravenous analgesia (PCIA) was performed in GA group, and patient-controlled epidural analgesia (PCEA) was performed in GE group after surgery. Heart rate (HR),mean arterial pressure (MAP), ScvO2, ect .were continuously monitored until patients leaved postanethesia care unit (PACU). Blood was obtained synchronously from central venous and radial artery for blood gas analysis after entering operation room (T1), before closing abdomen (T2), before closing the chest (T3) and before leaving PACU, and Then Pcv-aCO2 and Dcv-aLac were calculated.Visual analogue scale(VAS) was recorded in postoperative day 1(POD1) and day 2(POD2), and incidence of postoperative complications were recorded. Results There was no significant differences in general demographic data and clinical data between two groups. Compared with GA group, HR and MAP significantly decreased in GE group (P<0.05), but it was still within the normal range. At the time point of T4,ScvO2 in GE group significantly increased (P<0.05) compared with GA group, while there was no significant differences in Pcv-aCO2 and Dcv-aLac at the other time points. Blood gas analysis showed that Pcv-aCO2 and Dcv-aLac decreased significantly in GE group at the time points of T2, T3 and T4 compared with GA group (P<0.05), as well as the incidence of postoperative complications (P<0.05). Conclusions Compared with general anesthesia, general anesthesia combined with thoracic epidural anesthesia can effectively increase ScvO2, and decrease Pcv-aCO2 and Dcv-aLac, thereby improving oxygen balance and thus decreasing the incidence of postoperative complications. [ABSTRACT FROM AUTHOR]