Effectiveness of the closed-loop control system.

<p>Data are presented as mean ± SD.</p><p>Closed-loop = automated control of propofol infusion group guided by the bispectral index; Opened-loop = manual control infusion group guided by the bispectral index; BIS<40(%) = percentage of time in which the BIS value was less than a value of 40; 4060(%) = percentage of time in which the BIS value was greater than a value of 60; SR = burst suppression ratio was calculated as SR>10% 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.</p><p>Effectiveness of the closed-loop control system.