PERIOPERATIVE DEXMEDETOMIDINE VERSUS KETAMINE INFUSION FOR PREVENTION OF CHRONIC PAIN AFTER TOTAL KNEE REPLACEMENT: A PLACEBO-CONTROLLED STUDY

Dr. Tarek Refat El Hefni, M.D.*, Dr. Mohamed Zaki Youssef, M.D., Dr. Mohamad Abou Al-Neaj, M.D., Dr. Ahmed Hassan Abouhelwo, M.D. and Dr. Mohamed Mahmoud Elfekky, M.D.

ABSTRACT

Objectives: To evaluate effect of perioperative administration of Dexmedetomidine or ketamine infusion during Total Knee Replacement on acute postoperative pain and chronic neuropathic pain. Patients & Methods: Sixty patients assigned for Total knee replacement were divided into Group C received placebo, Group D and Group K received bolus followed by Intraoperative and Postoperative infusions of Dexmedetomidine and Ketamine, respectively. Intraoperative monitoring included heart rate and mean arterial pressure. Postoperative monitoring included pain severity assessed using numeric rating scale for 24-hr and somatic/sensory NPP using Douleur neuropathique 4 questions (DN4) Neuropathic pain diagnostic questionnaire evaluated preoperatively and 6-weeks and 3-months Postoperative. Patients satisfaction with the analgesic procedure was assessed with 4-points scale questionnaire. Results: Hemodynamic measures, especially in response to induction and intubation, were increased with Ketamine, but decreased with Dexmedetomidine infusion. During rest, pain scores and number of requests of rescue analgesia were significantly lower with Dexmedetomidine and Ketamine than placebo with significant difference in favor of Dexmedetomidine and 16 patients did not require rescue analgesia as long as they are in rest. During movement, 56 patients required rescue analgesia with significantly lower frequency with Dexmedetomidine than Ketamine and placebo and with Ketamine versus placebo. Duration till first request during rest was significantly longer and consumed dose of morphine was significantly lower with Dexmedetomidine than Ketamine and placebo and with Ketamine versus placebo. DN4 scores significantly improved than preoperative scores in all patients with significantly lower scores with Dexmedetomidine than Ketamine and placebo and with Ketamine versus placebo. All patients were satisfied by their 3-month outcome with significantly higher scores with Dexmedetomidine than Ketamine and placebo and with Ketamine versus placebo. Conclusion: Perioperative analgesic infusion helped to improve functional outcome through acute and chronic pain alleviation. Dexmedetomidine perioperative infusion did better than Ketamine infusion for pain relieve and improvement of functional outcome and patients' satisfaction.

Keywords: Total knee replacement, Dexmedetomidine, Ketamine, Postoperative pain, chronic neuropathic