Children often suffer acute pain,awakening delirium, anxiety and depression after operation which may affect the recovery of children. S (+) - ketamine has been described to decrease acute pain and opioid consumption,but it needs to confirm for chinese children undergoing surgery.~Objective:~To evaluate the analgesic effect of perioperative administration of S (+) - ketamine on postoperative acute pain in children undergoing surgery, and explore the effects of S (+) - ketamine on postoperative awakening delirium, postoperative anxiety and depression mood ,as well find the best usage, including dose, timing, compatibility, and type of operation.
A multicenter, randomized, open-label, active controlled pragmatic clinical trial that evaluates the safety and efficacy of S (+) -ketamine for postoperative acute pain in children in perioperative settings.