Fig. 5. Illustration of time evolution of infusion rate and plasma concentration for propofol and sufentanil observed in the best, median, and worst patients, limited to the first 660 min. The left axis represents the infusion rate, and the right axis represents the plasma concentration of the drugs. The white dotted line represents the target concentration, and the black dotted line represents the measured concentration. Grey rectangles represent the flow rates applied, and black arrows indicate modifications of target concentration indicated by an algorithm decision.