Efficacy and Safety of S-ketamine in Elderly Patients Undergoing Non-cardiac Surgery: a RCT（ESSENCE）

Intravenous infusion of esketamine: after induction, a single dose of 0.25 mg/kg before skin incision，and continuous 0.125 mg/kg/h until 30 min before surgery was stopped.

after induction, a single intravenous infusion of an equal amount of 0.9% saline before skin incision, followed by a continuous infusion at the same rate as the test group until 30 min before surgical cessation.