Blood glucose control during cardiac surgery

Since the strict blood glucose control by intensive insulin therapy was introduced as a life-saving maneuver, a lot of beneficial effects have been reported. The intensive insulin therapy has also been recommended in cardiac surgeries, particularly with cardiopulmonary bypass (CPB) which often induces hyperglycemia resulting from the excessive stress response. Recently, however, some groups have reported that intensive insulin therapy often leads to a serious complication like hypoglycemia, and they have expressed opposition to the therapeutic benefit. These studies indicated that the same target level of blood glucose did not provide the beneficial outcome to all patients, and that the optimal level of blood glucose differed depending on the individual patient and care setting. In order to determine the target level for blood glucose resulting in the lowest risk-to-benefit ratio, we must take into account various factors, such as variability of blood glucose concentration, presence or absence of diabetes, care setting, and perioperative nutritional management.