Most clinicians accept that prevention of uncontrolled hyperglycaemia is desirable. However, the optimal blood glucose range is controversial and, as yet, there are no current fixed national standards or guidelines. What we do know is that, in mixed adult populations of critically
ill medical and surgical patients, hyperglycaemia is associated with poor clinical outcomes,1,2 yet tight glucose control (4.4-6.1 mmol/l) using intensive insulin therapy is thought to have no mortality benefit and a significant increased frequency of hypoglycaemia.5 Therefore, an aim of maintaining a more liberal target blood glucose level of 7.5-10 mmol/l is encouraged.6,7 This range avoids marked hyperglycaemia, while minimising the risks of hypoglycaemia.
Based upon the available evidence, the best practice for general adult intensive care would appear to be that:
- hyperglycaemia is defined as a blood glucose level greater than 10 mmol/l
- the routine use of intravenous fluids containing glucose is minimised
- insulin should be administered when blood glucose levels are persistently elevated (greater than 10 mmol/l for over six hours)
- short-acting insulin should be used and delivered to target blood glucose levels of 7.5–10 mmol/l
- if intravenous insulin therapy is required, the patient must also be receiving some form of carbohydrate intake (either enterally fed, total parenteral nutrition or intravenous dextrose)
- if intravenous insulin is delivered through a peripheral cannula then we recommend running intravenous insulin and dextrose together to prevent inadvertent hypo/ hyperglycaemia if a cannula fails
- careful monitoring of blood glucose is essential to achieve glycaemic control while avoiding the potential harmful effects of hypoglycaemia.
