How fast can glucose be infused in the perioperative setting?

BACKGROUND: How the initial infusion rate of glucose solution should be set to avoid hyperglycemia in the perioperative setting is unclear. METHODS: Computer simulations were performed based on data from seven studies where the kinetics of glucose was calculated using a one-compartment model. Glucose had been infused intravenously on 44 occasions to volunteers and on 256 occasions to surgical patients at various stages of the perioperative process. The rates that yield plasma glucose concentrations of 7, 9, and 12 mmol/l were calculated and standardized to a 5 % glucose solution infused in a subject weighing 70 kg. RESULTS: The lowest infusion rates were found during surgery and the first hours after surgery. No more than 0.5 ml/min of glucose 5 % could be infused if plasma glucose above 7 mmol/l was not allowed, while 2 ml/min maintained a steady state concentration of 9 mmol/l. Intermediate infusion rates could be used in the preoperative period and 1-2 days after moderate-sized surgery (e.g., hysterectomy or hip replacement). Here, the half-lives averaged 30 min, which means that plasma glucose would rise by another 25 % if a control sample is taken 1 h after a continuous infusion is initiated. The highest infusion rates were found in non-surgical volunteers, where 8 ml/min could be infused before 9 mmol/l was reached. CONCLUSIONS: Computer simulations suggested that rates of infusion of glucose should be reduced by 50 % in the perioperative period and a further 50 % on the day of surgery in order to avoid hyperglycemia.