Dysglycaemia is frequently seen in the intensive care unit (ICU). Hyperglycaemia, hypoglycaemia and glycaemic variability are all independently associated with mortality and morbidity in critically-ill patients. It is common practice to treat hypergycaemia in these patients, while at the same time preventing hypoglycaemia and glycaemic variability. Insulin infusion is preferred over oral anti–hyperglycaemic agents for glucose control in the ICU because of the highly unpredictable biological availability of oral anti-hyperglycaemic agents during critical illness. Many oral anti–hyperglycaemic agents are relatively contraindicated in critically-ill patients. Intravenously-administered insulin has a predictable effect on blood glucose levels, in particular because of its short half-life. Notably, effective and safe insulin titration requires frequent blood glucose measurements, a dedicated lumen of a central venous catheter for infusion of insulin, an accurate syringe pump, and trained nurses for delicate adoptions of the infusion rate. Insulin infusion increases the risk of hypoglycaemia, which should be prevented at all times. In addition, precautions should be taken against overcorrection of hypoglycaemia, using only small amounts of glucose. Whether glycaemic variability can be kept minimal is uncertain. Use of continuous glucose measuring devices has the potential to improve glycaemic control in critically-ill patients.
Glycaemic variability and Mortality in critically ill patients
