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.