BIS levels in the group A were maintained at the same level, the target concentration of propofol in the group B were kept constant.BP, HR, SPO2, T and BIS were recorded at deferent time.

• 组维持脑电双频指数(BIS)在同一水平，B组丙泊酚靶控浓度保持恒定，记录各时间段血压(BP)、心率(HR)、血饱和度(SPO2)、体温(T)、BIS值、丙泊酚用量及麻醉苏醒时间。