Hyperglycemia, a common feature in critically ill patients, was traditionally perceived as an adequate stress response reflecting the severity of the disease state and was treated only if glycemia exceeded 11–13.5 mmol/L. In recent studies in intensive care patients, we showed that tight glycemic control (TGC) with intensive insulin therapy (IIT) reduced the risk of organ failure and death (1). In critically ill children, peak blood glucose (BG) and duration of hyperglycemia are associated with risk of mortality (2). Implementing TGC and avoiding hypoglycemia with intensive insulin therapy requires frequent BG sampling. Microdialysis of interstitial fluid (ISF) is a promising approach to reduce diagnostic blood loss. Continuously sampling dialyzed ISF and converting the ISF glucose concentration (IFG) to a BG value is a promising new method for glucose monitoring in diabetes patients. We conducted a prospective clinical trial in critically ill children to evaluate the feasibility of prolonged subcutaneous microdialysis and the correlation between BG and IFG. The study was approved by the Institutional Ethical Review Board. Twenty children were …