A fter getting satisfied spinal anesthesia, target-controlled infusion was established. Marsh pharmacokinetic parameters were used in group P and group P/F , and Avram pharmacokinetic parameters were used in group M .

• 椎管内麻醉完善后给予靶控输注，P组和P/F组选用Marsh靶控药代药效学模型，M组选用Avram靶控药代药效学模型，选择效应室浓度为靶控浓度。