The Effect of Perioperative Ketamine on Acute and Chronic Pain After Major Back Surgery

50 ml syringes provided by the HUG pharmacy will contain 1% ketamine or 0.9% NaCl. After induction and before start of surgery, patients will receive an intravenous bolus of 0.025 ml/kg of the study solution (corresponding to 0.25 mg/kg ketamine). Maintenance will be with a syringe driver at a rate of 0.025 ml/kg/h (corresponding to 0.25 mg/kg/h ketamine) until one hour before the end of surgery, and will then be decreased to a rate of 0.01 ml/kg/h (corresponding to 0.1 mg/kg/h ketamine) throughout the stay in the recovery room (usually 2 to 3 hours). The infusion will be stopped when the patient leaves the recovery room.

50 ml syringes provided by the HUG pharmacy will contain 1% ketamine or 0.9% NaCl. After induction and before start of surgery, patients will receive an intravenous bolus of 0.025 ml/kg of the study solution (corresponding to 0.25 mg/kg ketamine). Maintenance will be with a syringe driver at a rate of 0.025 ml/kg/h (corresponding to 0.25 mg/kg/h ketamine) until one hour before the end of surgery, and will then be decreased to a rate of 0.01 ml/kg/h (corresponding to 0.1 mg/kg/h ketamine) throughout the stay in the recovery room (usually 2 to 3 hours). The infusion will be stopped when the patient leaves the recovery room.