Perioperative glucose control: living in uncertain times--Continuing Professional Development

Hyperglycemia occurs frequently in surgical patients. The objective of this Continuing Professional Development (CPD) module is to review glucose physiology and pathophysiology and provide an update on the practical management of perioperative glucose based on recently published randomized controlled trials (RCTs).

In the mid 2000s, several professional medical organizations recommended the implementation of strict glucose control (glucose concentrations 4.4 to 6.1 mmol·L(-1)). However, the publication of new randomized controlled trials has dampened the initial enthusiasm. While the optimal glucose target range remains a matter of debate, hyperglycemia has been associated with increased morbidity and mortality in a variety of clinical settings. However, strict glucose control is associated with a sixfold increase in episodes of severe hypoglycemia (glucose levels < 2.2 mmol·L(-1)), which has also been linked with increased mortality. For critically ill patients, the American Diabetes Association and the American Association of Clinical Endocrinologists recommend aiming for a blood glucose level from 7.8 to 10.0 mmol·L(-1). While no specific target range can be recommended as yet during major surgery, glucose levels should be kept < 10.0 mmol·L(-1). In critically ill patients, glucose measured from capillary blood may give a falsely elevated value, so arterial blood sampling is preferred when measuring glucose. Frequent arterial blood glucose determination using an arterial blood gas analyzer or an International Organization for Standardization (ISO) 15197-compliant glucometer is crucial to avoid and detect deleterious hypoglycemic episodes.

Although there is agreement that both hyperglycemia and hypoglycemia are deleterious, there is no consensus on the target glucose values to enhance clinical outcomes.