Glycemic control in the ICU reduces morbidity in many areas and overall mortality in the critically ill.  The difficulties in establishing a glycemic control policy in the ICU are challenging.  Initially, fear will be the major obstacle to overcome.  Doctors fear causing hypoglycemia and may not know appropriate dosing techniques.  Nurses fear hypoglycemia and remain concerned about the appropriateness of adjustments to the intravenous rate of insulin administration given the kinetics of insulin usage.  Once these barriers are overcome, ICU patients receive better care and achieve one of their likely goals: the best known science has been applied to their care. 

Insulin, Glucose Co-Administration:

Studies supporting the role of glycemic control have used continuous infusion of insulin and glucose.  The design employed in the foundational study by Van den Berghe et al. employed a continuous infusion of insulin to maintain glucose between 80 and 110 mg/dL (4.4–6.1 mmol/L) (94 guidelines).  [Van den Berghe et al. Outcome benefit of intensive insulin therapy in the critically ill: Insulin dose versus glycemic control. Critical Care Medicine. 2003;31(2):359–366.]  Exogenous glucose was begun simultaneously with insulin with frequent monitoring of glucose (every 1 hour) and intensity of monitoring was greatest at the time of initiation of insulin. 

Frequency of Monitoring Serum Glucose:

With this protocol, glucose should be monitored frequently after initiation of the protocol (every 30 to 60 minutes) and on a regular basis (every 4 hours) once the blood glucose concentration has stabilized.  This protocol was provided by the investigators as an appendix to their study and can be found on the website of the New England Journal of Medicine.  In brief, this protocol leads to a strategy of maintaining normoglycemia with insulin (0.04 units·kg^-1·hour^-1) during normal intake of glucose (9 g/hr) and calories (19 kcal·kg^-1·day^-1).

Watch for Hypoglycemia:

For medical patients, we recommend clinicians pay particular attention to glycemic control to prevent metabolic complications and to ensure adequate nutritional support.  Hypoglycemia may occur when coordinating tight glycemic control.  The glucose control may be better if appropriate safety controls can also be put in place.  Implementing tight glycemic control can be dangerous without adequate staff education and a written, explicit protocol, which may help to prevent episodes of hypoglycemia.

Nutritional Support:

A strategy of glycemic control should include a nutrition protocol with the preferential use of the enteral route.  This strategy of strict glycemic control should be carefully coordinated with the level of nutritional support and metabolic status, which changes frequently in critically-ill patients.