The dose-response curve in the SP group was shifted to the left in the LPF(-) group. a: Central nervous system effect at the end of infusion in the LPF(-) group. b: Central nervous system effect at the end of infusion in the SP group. c: Central nervous system effect at the extubation in the SP and LPF(-) groups. Open circle and open triangle: SP group. Filled circle and filled triangle: LPF(-) group. X1 and X2 refer to the difference between the log predicted concentration at the end of infusion and that at the extubation in the SP and LPF(-) groups, respectively. X2 is significantly greater than X1. Y1 and Y2 refer to the change in response between the SP and LPF(-) groups, respectively. Since the triangleΔ○□ and the triangle ●▲■ are similar figures. The ratio of Y2 to Y1 is determined by a following formula, Y2/Y1 = X2 /X1. Because X2 is significantly greater than X1, Y2 is estimated to be larger than Y1. SP, short period group; LPF(-), long period group without flumazenil.