Magnesium and Rotational Thromboelastometry (ROTEM) in Colorectal Cancer Surgery

Magnesium sulphate is given to the patients during the colorectal cancer surgery under the hypothesis that it would attenuate the postoperative hypercoagulability. The investigators intend to characterize the changes of coagulation in colorectal cancer patients by using the point-of-care device after the infusion of magnesium sulphate.