LAUSR

Background Sub-anesthetic iv ketamine acts as an analgesic and has opioid-sparing effects, particularly for acute postoperative pain. Primary aim of this study was to evaluate the non-inferiority of sub-anesthetic iv ketamine vs caudal bupivacaine for postoperative analgesia in children. Methods Children below six years were enrolled in this single-blind study and randomized to receive either sub-anesthetic iv ketamine (0.3 mg/kg) or 1 ml/kg of caudal 0.125% bupivacaine, along with general anesthesia. Postoperative pain was assessed with the FLACC scale at 30 minutes, and at one, two, three, and six hours. Intra and postoperative opioid consumption, time to extubation, postoperative vomiting (POV), postoperative agitation, sedation, and inflammatory markers (serum IL-6 and TNF-α) were also assessed. Results One hundred and forty-one children completed the study, 71 in the ketamine and 70 in the caudal group. The cumulative proportion of children without significant postoperative pain (FLACC score < 4) until six hours post-surgery was 45.1% in the ketamine group vs 72.9% in the caudal group (P < 0.001). More children required an additional dose of intraoperative fentanyl (33.8% vs 5.7%; P < 0.001) and postoperative tramadol (54.9% vs. 27.1%; P < 0.001) in the ketamine group. Postoperative agitation, (4.3% vs. 9.9%; P = 0.19) and sedation (32.8% vs 22.5%; P = 0.17) were similar in the groups. Time to extubation, POV, baseline and post-surgical inflammatory markers were comparable. Conclusions Sub-anesthetic ketamine is inferior to caudal bupivacaine for postoperative analgesia in children below six years undergoing infra-umbilical surgeries but results in similar postoperative outcomes.