Methods Three ICUs developed and implemented an evidence-based guideline for IIT; three ICUs with no change in blood glucose control served as control ICUs. In the guideline ICUs, the IIT practice change comprised two periods: in the fi rst year after implementation of the guideline, physicians and nurses used the guideline together; in the second year the guideline was applied solely by nurses. BGL collection and analysis included the 1 year before implementation of the guideline.