[How much insulin does the critical ill need?].

Metabolism and nutrition of the critical ill are dynamic parameters of the severe disease influencing the blood glucose concentration. After the finding of increased survival in an initial study in tight glucose control, further large multicenter trials could not show such a benefit and even an increased mortality has been found. Hyperglycemia may be a feature of the stress metabolism and is possibly an adaptive process. Next to the endogenous response, therapy with catecholamines and glucosteroids impacts the response to insulin and the glucose metabolism. Hypo- and hypercaloric nutrition also interact with the insulin therapy. Nutritional therapy should be adapted to the actual state of the patient avoiding hypercaloric feeding and an energy deficit. Using this framework, therapy with insulin may be used to achieve a targeted range of glucose avoiding an increased risk of hypoglycaemia.