The effect of a small dose of ketamine on postoperative analgesia and cytokine changes after laparoscopic cholecystectomy

Background and objectives: In this study we assesed the effect of a small dose of ketamine on the production of TNFα, IL-1β and IL-6 and the postoperative pain in patients undergoing laparoscopic cholecystectomy. Methods: Fifty patients undergoing laparoscopic cholecystectomy were randomized in two equal groups. Patients in the ketamine group after induction in anesthesia received ketamine – 025 mg/kg-1. At the same time patients from the control group received sodium chloride. Postoperatively, the pain was assessed with VAS at periods of 30 min at 1, 2, 4, 8, 18, 24 and 48 hours. TNFα, IL-1β and IL-6 were evaluated before surgery at 4, 18 and 24h after the operation. Results: Differences of mean values of TNFα and IL-1β between the two groups in the postoperative period were not significant. Mean values of IL-6 in the investigated group A were significantly lower than the mean values of IL-6 in the investigated group B after the 4th hour (p = 0.00990), after the 18th hour (p = 0.00133) and as after the 24th hour following surgery (p = 000860). the difference in pain intensityaccording to the VAS scale was also statistically significantly smaller in group A after 30 min, 1,2,8 and 12 hours after surgery. Conclusions: The addition of a small-dose of ketamine in patiens undergoing laparoscopic cholecystectomy resulted in attenuation of secretion of TNFα, IL-1β, IL-6 and reduction of postoperative pain. Key words: ketamine, postoperative pain, proinflammatory cytokines