Colloid vs Crystalloid

Primary objectives: The purpose of the trial is to test the hypothesis that maximising circulating volume intra-operatively with colloid suspended in balanced crystalloid solution reduces post-operative morbidity compared to balanced crystalloid alone, in medium-to-high-risk patients undergoing major elective colorectal surgery.
Primary endpoints: Incidence of Gastrointestinal morbidity on the fifth postoperative day. Gastrointestinal morbidity is defined as the inability to tolerate either oral diet or nasogastric feed.This has been chosen as, in a previous trial in this institution (submitted for publication), this measure correlated very closely with hospital length of stay and other measures of morbidity. It is easily measured.