Analgesic Effects of Low-dose S-ketamine in Major Spine Fusion Surgery

"After anesthesia induction, a bolus of 0.15 mg/kg S-ketamine is injected intravenously about 30 min before incision; this is followed by a continuous infusion at a rate of 0.15 mg/kg/h until 1 hour before the end of surgery.~After surgery, patient-controlled analgesia is provided. The pump is established with S-ketamine 25 mg, dexmedetomidine 100 microgram, and sufentanil 100 microgram, diluted with normal saline to 100 ml. The pump is programmed to deliver 2-ml boluses with a background infusion rate at 1 ml /h and a 10-min lockout interval."

"After anesthesia induction, a bolus of placebo (normal saline) in the same volume is injected intravenously about 30 min before incision; this is followed by a continuous infusion of placebo at the same rate until 1 hour before the end of surgery.~After surgery, patient-controlled analgesia is provided. The pump is established with placebo, dexmedetomidine 100 microgram and sufentanil 100 microgram, diluted with normal saline to 100 ml. The pump is programmed to deliver 2-ml boluses with a background infusion rate at 1 ml /h and a 10-min lockout interval."