HYPERGLYCEMIA IN PATIENTS UNDERGOING ELECTIVE CARDIOPULMONARY BYPASS PROCEDURES

Abstract

Introduction: Patients undergoing procedures involving the use of cardiopulmonary bypass (CPB) are subjected to derangements causing hyperglycemia, even without exogenous glucose administration, which may contribute to postoperative morbidity from neurologic and renal dysfunction, infection, and poor wound healing. Blood glucose is routinely monitored at the following times: preoperatively, after induction of anesthesia, every 30 minutes while on CPB, after separation from CPB, and while in the intensive care unit. We have defined hyperglycemia as a serum glucose of >180 mg/dl, and persistent hyperglycemia as glucose >180 mg/dl on more than one measurement. We evaluated the incidence of hyperglycemia, risk factors for its development, and the incidence of insulin administration to maintain normoglycemia. Methods: During a 5 week period, 55 patients undergoing elective cardiac surgery utilizing CPB were monitored for development of hyperglycemia from the start of induction of anesthesia to the first 24 hours postoperatively in the intensive care unit. Presumptive factors which may increase the risk of developing hyperglycemia were recorded, including body mass index (BMI), preoperative diagnosis of diabetes, use of methylprednisolone, temperature on CPB of <32 degrees, CPB time, use of epinephrine, and use of inotropes other than epinephrine. Persistent hyperglycemia, insulin administration, and the requirement of an insulin infusion to maintain normoglycemia were also recorded. Data were analyzed by logistic regression. Results: Hyperglycemia occurred in 84%, and persistent hyperglycemia in 76% of patients. Prior history of diabetes, steroid administration, epinephrine, other inotropic support, temperature on CPB <32 degrees, CPB time, or BMI were not significant risk factors for hyperglycemia. The prevalence of diabetics in our patient population was 24%. Insulin was administered in 83% of patients who developed hyperglycemia, and an insulin infusion was used in 47% of the total patient population to maintain blood glucose below 180mg/dl. Conclusions: Hyperglycemia is a common occurrence; in patients undergoing elective cardiac surgical procedures utilizing CPB and requires insulin administration in the majority of cases. Prior history of diabetes mellitus, use of steroids, inotropic support, hypothermia, BMI, and CPB time were not significant risk factors.