Perioperative Lidocaine and Ketamine in Abdominal Surgery

Perioperative lidocaine and ketamine infusion (see below for dosages and timings)

Perioperative lidocaine infusion (1.5 mg/kg bolus followed by an infusion of 2 mg/kg/hour based on actual body weight; the bolus and infusion will be started after anesthesia induction and before surgical incision, and continued until 1 hour after transfer from the operating room to the PACU)

Perioperative ketamine infusion (0.5 mg/kg bolus followed by an infusion of 0.3 mg/kg/hour based on actual body weight; the bolus and infusion will be started after anesthesia induction and before surgical incision, and continued until 1 hour after transfer from the operating room to the PACU)

Perioperative placebo infusion (normal saline)