Effect of Goal-directed Fluid Therapy on Postoperative Complications

* It has been known that the recent application of a goal-directed fluid therapy (GDFT) to the intraoperative fluid infusion in patients contributes to decreasing the prevalence of postoperative complications and shortening the length of study in the intensive care unit as well as hospital stay compared with conventional methods. * Laparoscopic surgery is in a trend that its application is being expanded recently, but there has been no report on the application of GDFT to laparoscopic surgery so far. * To this end, this study aims to apply the intraoperative GDFT protocol in patients undergoing laparoscopic hepatobiliary or pancreatic surgery and to find out whether there is any difference in postoperative recovery and incidences of postoperative complications, by comparing with patients applied with the fluid therapy using existing conventional methods