Effects of Perioperative Intravenous Lidocaine and Ketamine on Acute and Chronic Pain After Open Nephrectomy

Overview

Open nephrectomy is one of the most common surgical procedures in urologic practice. Pain after surgery remains a significant clinical problem as it impairs recovery adversely and may lead to the transition to chronic pain. The open approach represents a major physical trauma including postoperative pain and discomfort in the convalescence period. Adequate control of postoperative pain facilitates earlier mobilization and rehabilitation. Patient-controlled analgesia (PCA) is effective to treat pain at rest, but seems to be inadequate for dynamic analgesia and may also elicit side effects that may delay hospital discharge. Preventing early and late postsurgical pain is an important challenge for anesthesiologists and surgeons. Ketamine (N-Methyl-D-Aspartate receptor antagonist) and lidocaine (sodium channel blocker) are popular analgesic adjuvants for improving perioperative pain management. The investigators designed this double-blind, placebo controlled study to test and compare the preventive effects of perioperative intravenous ketamine and lidocaine on early and chronic pain after elective open nephrectomy. The investigators propose a double-blind placebo-controlled study of patients undergoing elective open nephrectomy. All patients will receive normal "patient-controlled analgesia morphine" in addition to study drugs or placebo. Research will be conducted at Charles Nicolle teaching hospital.

Participants will be randomized into one of three study groups: Group L: intravenous lidocaine: bolus of 1.5 mg/kg at induction of anesthesia followed by infusion of 1 mg/kg/h intraoperatively and for 24 h postoperatively. Group K: Ketamine: bolus of 0.15 mg/kg followed by infusion of 0.1 mg/kg/h intraoperatively and for 24 h postoperatively. Control Group C: an equal volume of saline. The anesthetic technique will be standardized, and the postoperative assessments included pain scores, opioid consumption, recovery of bowel function and 6-minute walk distance (6-MWD) on the fourth postoperative morning. At 3 months, patients will be questioned for chronic postoperative pain using the Neuropathic Pain 4 questionnaire.