Acute glycemic control in critically ill perioperative patients; the impact of parenteral nutrition on the effect of intensive insulin therapy

Hyperglycemia is common in critically ill patients. Recently the international multicentre NICE-SUGAR study reported increased mortality with this approach and recent meta-analyses do not support adopting intensive glucose control for critically ill patients. One possible explanation of the different effect of intensive insulin therapy between Leuven study and NICE-SUGAR study is how aggressively parenteral nutrition was applied. In Leuven study, parenteral nutrition was applied aggressively (total intravenous intake of non-protein calorie; 12-18 kcal x kg(-1) day(-1)), while in NICE-SUGAR study, "permissive hypo-nutrition" (total intravenous intake of non-protein calorie; 1-1.5 kcal x kg(-1) x day(-1)) was applied. As recent meta-analysis showed that the percentage of calories given intravenously was significantly associated with a treatment effect of intensive insulin therapy, this difference might be relevant. Recently, EPaNC trial showed that aggressive parenteral nutrition may increase infection rate and worsen outcomes, even though they apply intensive insulin therapy in all participating patients. The results of the NICE-SUGAR study and EPaNIC trial have resulted in the more moderate recommendation to target a blood glucose concentration between 144 and 180 mg x dl(-1) and less aggressive parenteral nutrition. Until another level I evidence is available, clinicians would be well advised to abide by the age-old adage, "First, do no harm".