Effectiveness of the closed-loop control system.

Data are presented as mean ± SD.Closed-loop = automated control of propofol infusion group guided by the bispectral index; Opened-loop = manual control infusion group guided by the bispectral index; BIS10% lasting at least one minute; PE = Performance error was defined as the difference between the actual value and the set value of BIS; MDPE = Median performance error; MDAPE = Median absolute performance error; Wobble = the intraindividual variability in PE; GS = Global score of BIS.Effectiveness of the closed-loop control system.