Effects of hyperglycemia and continuous intravenous insulin on outcomes of surgical patients

Background: Hyperglycemia in critically ill patients has been associated with increased morbidity and mortality. It is unclear to what degree hyperglycemia should be regulated in a mixed surgical population. Study Design: A retrospective chart review of 210 surgical patients in the intensive care unit (ICU) was performed. All patients were placed on an intravenous insulin protocol targeted to a blood glucose (BG) of 80-140 mg/dL. Outcomes were compared between surgical patients with controlled BG levels (80-140 mg/dL) versus uncontrolled levels (>140 mg/dL). Results: The mortality rate of this population was 12%, 5% in the controlled BG group compared with 18% in the uncontrolled BG group (P < 0.01). After adjusting for covariates, the mortality rate of the uncontrolled blood glucose group was significantly greater (OR = 4.8, 95% CI 1.4-20; P = 0.02). The overall hypoglycemic rate was <1%, and was not associated with a higher mortality, P = 0.60. A greater mortality rate was associated with patients who spent a greater time with blood glucose values >181 mg/dL (OR = 1.3, 95% CI 1.1-1.6; P = 0.01). Conclusions: Increased mortality was associated with surgical patients in the uncontrolled blood glucose group compared with patients who were well controlled with insulin therapy. These results are comparable to previous studies and indicate that surgical patients are a population who may benefit from tighter glycemic control. Further investigations through prospective randomized studies are needed to fully evaluate the effects of hyperglycemia in a diverse surgical population as well as specific surgical subspecialties.