Tight glucose control in intensive care units: an update with an emphasis on nutritional issues

Tight glucose control in ICU patients is now regarded as a goal of successful care. Some challenge this on the basis that it produces no benefit and may cause harm. We review the recent literature with an emphasis on nutritional aspects.

Since 2001, several randomized controlled trials have examined the effect of tight glucose control in ICU patients, but only one showed an overall survival benefit. Glucose potassium insulin infusions have also produced variable results, and sometimes cause falls in plasma phosphate with potential consequences. Several studies have shown tight glucose control is labour-intensive and increases the incidence of hypoglycaemia, which could have profound effects, especially if cerebral perfusion is poor. Nutritional intake during tight glucose control has generally been poorly defined. Unintentional cessation of nutrition has been identified as a risk factor for hypoglycaemia. No difference in glucose control has been found between parenteral and enteral feeding.

Without knowledge of nutrition provision in terms of carbohydrate, total energy intake and route of administration, some studies are difficult to interpret. It is currently difficult to recommend routine use of tight glucose control in the ICU. Many clinicians have adopted regimes to control glucose between 5.0-9.0 mmol/l.