The aim of the study is to evaluate need of perioperative hydration by comparing conventional monitoring (the control group) to a more advanced approach (individualized goal-directed therapy, IGDT) (the intervention group). In addition to conventional cardiovascular monitoring (ECG, non-invasive blood pressure, Sp02) preoperative transthoracic echocardiography (TTE) and a intraoperative perioperative mini-invasive pulse-contour device (FloTrac™) will be used for the purpose.