Current controversies around tight glucose control in critically ill patients.

PURPOSE OF REVIEW: This review updates our knowledge on the benefits and risks of tight glucose control by intensive insulin therapy in critically ill patients, as well as discussing unanswered questions related to the subject.

RECENT FINDINGS: At the cellular level, the toxic effects of elevated and highly variable glucose concentration are related to an increase in oxidative stress and to several toxic intracellular derivates generated as by-products of the glycolytic pathway. Clinically, several recent studies have suggested that the optimal target for blood glucose may be higher than the 'normal' values of 4.4-6.1 mmol/l for various categories of patients. Also, the variability in glucose level appears to be an important determinant of glucose toxicity. Conflicting data on the hazards of hypoglycaemia are emerging.

SUMMARY: Practical recommendations for the implementation of tight glucose control using intensive insulin therapy cannot be disseminated until questions relating to optimal blood glucose level and the corresponding categories of patients have been resolved. The issues of glucose variability and the most efficient method of preventing hypoglycaemia will probably represent important parameters for comparing the safety and quality of protocols used for tight glucose control.