PERIOPERATIVE MEDICINE Anesthesiology 2010; 112:860 –71 Copyright © 2010, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins Role of Intraoperative and Postoperative Blood Glucose Concentrations in Predicting Outcomes after Cardiac Surgery Andra E. Duncan, M.D.,* Alaa Abd-Elsayed, M.D.,† Ankit Maheshwari, M.D.,‡ Meng Xu, M.S.,§ Edward Soltesz, M.D., M.P.H., Colleen G. Koch, M.D., M.S.# ABSTRACT Background: Severe hyperglycemia is associated with adverse outcomes after cardiac surgery. Whether intraoperative and postop- erative glucose concentrations equally impact outcomes is un- known. The objective of this investigation was to compare the ability of perioperative glucose concentrations and glycemic variability to predict adverse outcomes. Risk associated with decreasing incre- ments of glucose concentrations, hypoglycemia, and diabetic status was also examined. Methods: This retrospective analysis of prospectively collected data included 4,302 patients who underwent cardiac surgery between October 3, 2005 and May 31, 2007 at the Cleveland Clinic. Time- weighted mean intraoperative (Glc OR ) and postoperative (Glc ICU ) glu- cose concentrations were calculated. Patients were categorized as follows: Glc more than 200, 171–200, 141–170, and less than or equal to 140 mg/dl. Coefficient of variation was used to calculate glycemic variability. Logistic regression model with backward selec- tion assessed the relationship between glucose concentrations, vari- ability, and adverse outcomes while adjusting for potential confound- ers. Another model assessed the predictability of Glc OR and Glc ICU on adverse outcomes. Results: Both Glc OR and Glc ICU predicted risk for mortality and morbidity. Increased postoperative glycemic variability was associ- ated with increased risk for adverse outcomes. Severe hyperglyce- mia (Glc OR and Glc ICU  200 mg/dl) was associated with worse outcomes; however, decreasing increments of Glc OR did not con- sistently reduce risk. Glc OR less than or equal to 140 mg/dl was not associated with improved outcomes compared with severe hyper- glycemia, despite infrequent hypoglycemia. Diabetic status did not influence the effects of hyperglycemia. Conclusion: Perioperative glucose concentrations and glycemic variability are important in predicting outcomes after cardiac surgery. Incremental decreases of intraoperative glucose concentrations did not consistently reduce risk. Despite rare hypoglycemia, intraopera- tive glucose concentrations closest to normoglycemia were associ- ated with worse outcomes. S EVERE hyperglycemia is clearly associated with worse outcomes in hospitalized patients. 1,2 Hyperglycemia oc- curs commonly during the perioperative period and is asso- ciated with increased risk for mortality and morbidity. 3–5 Most investigations in surgical patients have focused on the influence of postoperative glucose concentrations on postop- erative outcomes. 1,3 Fewer reports have examined the influ- ence of glucose concentrations measured during the intraop- erative period. 4,5 Moreover, none of these reports has * Staff Anesthesiologist, # Professor of Anesthesiology, Depart- ments of Cardiothoracic Anesthesia and Outcomes Research, ‡ Res- ident, Department of General Anesthesia, § Senior Biostatistician, Department of Quantitative Health Sciences,  Staff Surgeon, De- partment of Thoracic and Cardiovascular Surgery, Cleveland Clinic, Cleveland, Ohio. † Resident, Department of Anesthesiology, Uni- versity of Cincinnati, Cincinnati, Ohio. Received from Department of Cardiothoracic Anesthesia, Cleve- land Clinic, Cleveland, Ohio. Submitted for publication August 29, 2009. Accepted for publication January 4, 2010. Support was pro- vided solely from institutional and/or departmental sources. Pre- sented at the American Society of Anesthesiologists Annual Meeting, New Orleans, Louisiana, October 20, 2009. Address correspondence to Dr. Duncan: Department of Cardio- thoracic Anesthesia, Cleveland Clinic Foundation, 9500 Euclid Av- enue/J4, Cleveland, Ohio 44195. duncana@ccf.org. Information on purchasing reprints may be found at www.anesthesiology.org or on the masthead page at the beginning of this issue. ANESTHESIOLOGY’s articles are made freely accessible to all readers, for personal use only, 6 months from the cover date of the issue. What We Already Know about This Topic ❖ Although hyperglycemia is associated with increased postop- erative morbidity and mortality, it is unclear whether intraop- erative and/or postoperative hyperglycemia are important to this association What This Article Tells Us That Is New ❖ In more than 4,000 patients who underwent cardiac surgery, both intraoperative and postoperative hyperglycemia more than 200 mg/dl were associated with increased morbidity and mortality in both patients with and without diabetes ❖ In contrast to the postoperative setting, maintaining serum glucose close to normoglycemia ( 140 mg/dl) intraopera- tively increased morbidity and mortality to the level of severe hyperglycemia ( 200 mg/dl) Presented at the Journal Symposium Session of the American Society of Anesthesiologists Annual Meeting, October 20, 2009.  Supplemental digital content is available for this article. 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