SAS
The SAS score of each patient was calculated from the recorded anaesthesia chart as described previously by Gawande et al30. The SAS score is the sum of the points from each category using the above three variables ranges from 0 to 10 points, and the determination of the intraoperative blood loss is based on both the weight of gauze used and the suction used. For patients underwent OPCABG, blood pressure and heart rate were measured invasively and monitored continuously throughout the surgical procedure.