Effects of ketamine on the patients with postoperative hyperalgesia after remifentanil-based anaesthesia

Objective To evaluate the preventive effects of ketamine on the patients with postoperative hyperalgesia after large-dose remifentanil-based anesthesia.Methods 60 patients undergoing laparoscopic cholecystectomy were randomly assigned to 3 groups(n=20),group R received intraoperative remifentanil by TCI at 4 μg/L,group K received intraoperative remifentanil by TCI at 4 μg/L and ketamine 0.5 mg/kg at skin closure,group C received no drug infusion.Anesthesia was maintained with sevoflurane.The four-level verbal rating scale after trachea extubation,VAS score at 2,4,12,24 hours after extubation were recorded.Results The emergence times were significantly shorter in the Group R and Group K than those in Group C(P0.05).Pain scores in Group R were significantly higher than those in Group K and group C during the first 15 postoperative minutes(P0.01).The VAS scores at 2,4 hours in group K were lower than those in group R(P0.05).More patients in Group R required analgesia than those in Group C and Group K.The adverse drug reaction showed no significant difference in three groups.Conclusion Small dose ketamine can attenuate postoperative hyperalgesia after large-dose remifentanil-based anesthesia and without increasing the incidence of side effects.