Effects of preemptive Ketamine on post-cesarean analgesic requirement

In a randomized, double blind study, we compared post operative pain and analgesic requirement in patients undergoing cesarean section with two types of general anesthesia: standardized general anesthesia (control group= 26 cases) and preemptive low-dose ketamine (0.2 mg/kg) administered prior to anesthesia induction (ketamine group= 27 cases). Postoperative analgesia was provided for both groups using morphine intravenously based on visual analogue scale (vas). After the operation we found that the time from the end of surgery to the first request for analgesic was longer in ketamine group (10.22±8 hrs) than in the control group (1.65±1.01 hrs) (p<0.001). Mean dose of morphine consumption over 24 hrs was less in the ketamine group (6.25± 3.45 mg) than in the control group (17.73± 4.08 mg) (p<0.001). Vas of pain scores were lower in ketamine group during 24 hrs (p<0.001). Apgar scores were similar between the groups. No patient in either group had postoperative hallucination. In conclusion, ketamine in low dose has a preemptive analgesia effect that reduces central sensitization in cesarean section and reduces postoperative analgesic requirement.