Besides, questions are raised what the optimal goals (healthy population derived normal values, preoperative values, maximal values) should be. Lately, studies have shown that optimising cardiac output and oxygen delivery to higher (supra-normal) values intra- and postoperatively did not affect post-operative complications rate, intensive care unit stay or hospital length of stay. Probably the target should be maintaining patient's blood flow and oxygen delivery at preinduction levels. The question was also raised in fluid management. Liberal approach can lead to oedema of the intestines and other tissues, which may be responsible for poor tissue healing and other complications. In abdominal surgery, protocol-based fluid restriction reduced the incidence of perioperative complications such as cardiopulmonary events and disturbances of bowel motility while improving wound and anastomotic healing and reducing hospital stay in comparison to liberal fluid management. One of the trials has shown 52% lower rate of major postoperative complications in restrictive group than in the conventional group.