Context. Elevated blood glucose levels occur frequently in the critically ill. Tight glucose control by intensive insulin treatment markedly improves clinical outcome.

Objective and Design: Randomized controlled trial comparing blood glucose control by a laptop-based model predictive control algorithm with a variable sampling rate (eMPC) against a routine glucose management protocol (RMP) in peri- and postoperative period.

Setting: Department of Cardiac Surgery, University Hospital.

Patients. 60 elective cardiac surgery patients.

Interventions. Elective cardiac surgery and treatment with continuous insulin infusion (eMPC) or continuous insulin infusion combined with i.v. insulin boluses (RMP) to maintain euglycemia (target range 4.4 - 6.1 mmol/l). 30 patients were randomized for eMPC and 30 for RMP treatment. Blood glucose was measured in 1-4 hour intervals as requested by each algorithm during surgery and post-operatively over 24 hours.

Main Outcome Measures. Mean blood glucose, percentage of time in target range, hypoglycemia events.

Results. Mean blood glucose was 6.2 ± 1.1 mmol/l in the eMPC vs. 7.2 ± 1.1 mmol/l in RMP group (p<0.05); percentage of time in the target range was 60.4 ± 22.8% for the eMPC vs. 27.5 ± 16.2% for RMP group (p<0.05). No severe hypoglycemia (blood glucose bellow 2.9 mmol/l) occured during the study. Mean insulin infusion rate was 4.7 ± 3.3 in eMPC vs. 2.6 ± 1.7 IU/h in RMP (p<0.05). Mean sampling interval was 1.5 ± 0.3 vs. 2.1 ± 0.2 hours (p<0.05).

Conclusions. Compared to RMP, the eMPC algorithm was more effective and comparably safe in maintaining euglycemia in cardiac surgery patients.