Rigorous intraoperative glycemic control may be of paramount importance in affecting outcomes after cardiac surgery. There is evidence that strict control of glucose levels postoperatively results in improved outcomes in patients undergoing cardiac surgery. There is currently no consensus on optimal management of hyperglycemia intraoperatively. The aim of this prospective randomized controlled clinical trial is to determine whether normalization of intraoperative glucose levels with insulin improves outcomes. The comparison group will be treated with current standard practice to control hyperglycemia during surgery. The primary outcome is a composite of mortality, sternal wound infections, prolonged pulmonary ventilation, cardiac arrhythmias (new-onset atrial fibrillation, heart block requiring permanent pacemaker, cardiac arrest), stroke and acute or worsening renal failure within 30 days after surgery. Secondary outcome measures are length of intensive care unit and hospital stay as well as safety and efficacy of the study insulin infusion protocol.