Dr. Kofke calls our attention to this prospective randomized study of tight intraoperative glucose control using insulin infusion compared to “conventional” management with tight control in both groups during the post operative period. Four hundred cardiac surgery patients were randomly assigned to tight glycemic control (blood glucose levels between 80 – 100 mg/dl) during surgery or conventional glucose control. Patients who did not become hyperglycemic during surgery were not included in the analysis. Pre operatively the glucose levels were similar in both groups. At the conclusion of cardiopulmonary bypass the mean blood glucose level in the tight control group was significantly lower (123 mg/dl) compared to 148 mg/dl in the conventional glucose control group. All patients in the intensive treatment group received insulin during surgery and 15% of the patients in the conventional therapy group received insulin. At the end of 24 hours in the ICU the mean glucose levels were the same in both groups (about 106 mg/dl, mean). The two groups did not differ in the primary composite endpoint of sternal infection, death, prolonged ventilation, cardiac arrhythmias, stroke or renal failure. Nor did investigators find a direct benefit from intraoperative from intensive insulin therapy for and of the individual components of the composite end point. In fact the reverse result was obtained. The intensive treatment group had significantly more strokes (8 vs. 1) and deaths (4 vs. 0) than the conventional treatment group. There was no treatment effect for length of stay in the ICU or hospital. The authors note that this does not directly contradict prior findings of benefits from tight glucose control as the key studies involved tight control vs. conventional control during the entire period from OR through ICU. It is possible that tight glucose control during the relatively brief period of surgery is not as important as tight glucose control during the longer post operative period. Gandhi GY et al: Intensive intraoperative insulin therapy versus conventional glucose management during cardiac surgery. Ann Intern Med 2007;146:233-243
Dr. WA Kofke is Professor of Anesthesiology at UPENN
David Smith, M.D., Ph.D.