Glycemic control in cardiac surgery: rationale and current evidence.

Studies in cardiac surgical patients have shown an association of hyperglycemia with increased incidences of sepsis, mediastinitis, prolonged mechanical ventilation, cardiac arrhythmias and longer intensive care and hospital stay. There is considerable controversy regarding appropriate glycemic management in these patients and in the definition of hyperglycemia and hypoglycemia or the blood sugar levels at which therapy should be initiated. There is also dilemma regarding the usage of "tight glycemic control" with studies showing conflicting evidences. Part of the controversy can be explained by the differing designs of these studies and the variable definitions of hyperglycemia and hypoglycemia.