Intensive insulin therapy in the ICU--reconciling the evidence

Hyperglycaemia during critical illness unequivocally correlates with adverse outcome. Three proof-of-concept randomized controlled trials have shown that preventing hyperglycaemia in patients admitted to the intensive care unit (ICU) reduces organ failure and mortality. A subsequent multicentre, randomized controlled trial found that targeting normoglycaemia in this patient population does not affect organ function differently than targeting an intermediate glucose level (7.8-10.0 mmol/l). However, an intermediate glucose target evoked less hypoglycaemia and, for currently unexplained reasons, also fewer deaths than a normoglycaemic target. Moreover, tolerating a caloric deficit, rather than providing nutrients parenterally, accelerated recovery from critical illness in the presence of normoglycaemia. Whether macronutrient restriction renders moderate hyperglycaemia less harmful remains to be investigated. Hence, if adequate monitoring tools and expertise are available, normoglycaemia remains the only proven effective target for insulin treatment of hyperglycaemia in ICU patients. However, if these conditions are not fulfilled in clinical practice, is an intermediate target range preferable? In the absence of hard evidence, common sense supports such an intermediate blood glucose target.