Comparison of preventive effects of tramadol and ketamine on remifentanil-induced postoperative hyperalgesia after neurosurgical anesthesia

Objective To compare the preventive effects oftramadol and ketamine on the patients with postoperative hyperalgesia after remifentanil-induced neurosurgical anesthesia.Methods One hundred and fifty patients undergoing craniotomy were assigned to tramadol group,ketamine group and normal saline group with 50 cases each by random digits table.Anesthesia was maintained with infusion of remifentanil [0.1-0.2μ g/( kg· min ) ],propofol and sevoflurane.Tramadol ( 1.5 mg/kg),ketamine (0.5 mg/kg) or normal saline was given before skin closing.The emergence time,trachea extubation time,patients required analgesia and tramadol consumption,reverse effect were recorded.The visual analog scale (VAS),Ramsay scores at 15,30,60,120 minutes after emergence were performed.Results Patients required analgesia and tramadol consumption in tramadol group and ketamine group were significantly lower than those in normal saline group (P ＜0.01 or ＜0.05 ).The occurrence of shiver in tramadol group was lower than that in normal saline group (P ＜0.05).VAS scores in tramadol group at 15,30 minutes and in ketamine group at 30 minutes after emergence were significantly lower than those in normal saline group (P＜ 0.05).Ramsay score in ketamine group at 15 minutes after emergence was higher than that in tramadol group and normal saline group [ (2.9 ±0.6) scores vs.(2.3 ±0.7) scores and (2.3 ±0.9) scores](P＜0.01).Conclusion Tramadol has a goodpreventive effect for postoperative hyperalgesia induced by remifentanil in neurosurgery compared with ketamine. Key words: Tramadol;  Ketamine;  Hyperalgesia;  Neurosurgical procedures