Hyperglycemia and perioperative glucose management

Abstract

Hyperglycemia is associated with increased mortality and morbidity in critically ill patients. Surgical patients commonly develop hyperglycemia related to the hypermetabolic stress response, which increases glucose production and causes insulin resistance. Although hyperglycemia is associated with worse outcomes, the treatment of hyperglycemia with insulin infusions has not provided consistent benefits. Despite early results, which suggested decreased mortality and other advantages of "tight" glucose control, later investigations found either no benefit or increased mortality when hyperglycemia was aggressively treated with insulin. Because of these conflicting data, the optimal glucose concentration to improve outcomes in critically ill patients is unknown. There is agreement, however, that hypoglycemia is an undesirable complication of intensive insulin therapy and should be avoided. In addition, the risk of increased glucose variability should be recognized, because of the associated increased risk for worse outcomes. Patients with diabetes mellitus experience chronic hyperglycemia and often require more intensive perioperative glucose management. When diabetic patients are evaluated before surgery, appropriate management of oral hypoglycemic agents is necessary as several of these agents warrant special consideration. Current recommendations for perioperative glucose management from national societies are varied, but, most suggest that tight glucose control may not be beneficial, while mild hyperglycemia appears to be well-tolerated.

Figure 1. Probability of Survival and Odds Ratios for Death, According to Treatment Group

Panel A shows Kaplan–Meier estimates for the probability of survival, which at 90 days was greater in the conventional-control group than in the intensive-control group (hazard ratio, 1.11; 95% confidence interval, 1.01 to 1.23; P = 0.03). Panel B shows the odds ratios (and 95% confidence intervals) for death from any cause in the intensive-control group as compared with the conventional-control group, among all patients and in six predefined pairs of subgroups. The size of the symbols indicates the relative numbers of deaths. The Acute Physiology and Chronic Health Evaluation II (APACHE II) score can range from 0 to 71, with higher scores indicating more severe organ dysfunction. Reprinted with permission. New England J Med. 2009; 360: 1283.

Figure 1. Probability of Survival and Odds Ratios for Death, According to Treatment Group

Panel A shows Kaplan–Meier estimates for the probability of survival, which at 90 days was greater in the conventional-control group than in the intensive-control group (hazard ratio, 1.11; 95% confidence interval, 1.01 to 1.23; P = 0.03). Panel B shows the odds ratios (and 95% confidence intervals) for death from any cause in the intensive-control group as compared with the conventional-control group, among all patients and in six predefined pairs of subgroups. The size of the symbols indicates the relative numbers of deaths. The Acute Physiology and Chronic Health Evaluation II (APACHE II) score can range from 0 to 71, with higher scores indicating more severe organ dysfunction. Reprinted with permission. New England J Med. 2009; 360: 1283.

Figure 2

Incidence of severe in-hospital morbidity between patients in whom intraoperative glycemic control was poor (4 consecutive glucose levels > 200 mg/dL) or tight. CV = cardiovascular morbidity; Inf: infectious morbidity; Neuro = neurologic morbidity; Resp = respiratory morbidity. *P<0.05 versus tight control. Reprinted with permission. Anesthesiology 2005; 103:687–94.

Figure 3

Univariate analysis comparing risk of adverse outcome between decreasing incremental mean glucose levels during the intraoperative period. *P≤0.001 overall between mean glucose levels for each individual outcome. #P≤ 0.001 between glucose > 200 mg/dL and glucose 141 −170 mg/dL. Reprinted with permission. Anesthesiology 2010; 112: 860.

Figure 4

Univariate analysis comparing risk of adverse outcome between decreasing incremental mean glucose levels during the initial postoperative period. *P≤0.001 overall between mean glucose levels for each individual outcome. #P≤ 0.001 between glucose > 200 mg/dL and glucose 141 −170 mg/dL. Reprinted with permission. Anesthesiology 2010; 112: 860.