Objective and design: To review and discuss selected literature, expert opinion, and conventional care of the hyperglycemic perioperative or critically ill patient.
Main points: Diabetes mellitus, the most commonly encountered perioperative endocrinopathy, continues to increase dramatically in prevalence. Diabetes is the sixth most common cause of death in the United States and significantly affects other more common causes of death such as cardiac disease and stroke. Diabetic patients commonly have microvascular and macrovascular pathology that influences their perioperative course and critical illness and increases morbidity and mortality rates during hospitalization. Since diabetics require more surgeries and receive critical care more frequently than their nondiabetic counterparts, preemptive identification and anticipation of diabetic complications and comorbidities, along with an optimized treatment plan, are the foundation for the proper intensive care of this growing patient population. Hyperglycemia occurs commonly in critically ill diabetic patients but also is frequent in those who have a history of normal glucose homeostasis. The new onset of hyperglycemia in critically ill patients is driven by excessive counterregulatory stress hormone release and high tissue and circulating concentrations of inflammatory cytokines. Aggressive glycemic management improves short- and long-term outcomes in diabetic patients with acute myocardial infarction and cardiac surgical patients. Most recently, "tight" glycemic control in both diabetic and nondiabetic hyperglycemic intensive care unit patients resulted in improved survival in selected surgical patients without excessive consequences related to hypoglycemia. The mechanisms of benefit of euglycemia appear to be multifactorial.
Conclusions: Up to 25% of patients admitted to the intensive care unit have previously diagnosed diabetes. Diabetics are most commonly admitted for treatment of complications of comorbid diseases. New-onset hyperglycemia also is common in critically ill patients, and it affects patient morbidity and mortality rates. A growing body of literature supports the benefits of tight glycemic control in certain patient populations. However, further data are needed about the optimal concentration of blood glucose, the role of maintaining euglycemia in a broader group of patients (including the medically critically ill), and the mechanisms of benefit of infused glucose and insulin.