Effects Of Dezocine Or Dexmetomidine Alone Or Combination Of The Two Agents On Remifentanil-induced Postoperative Hyperalgesia

This study is to compare the preventive efficacy, the influence on circulatory system and the adverse effects of dezocine or dexmedetomidine alone or combination of the two agents on remifentanil-induced postoperative hyperalgesia, to provide the basis for clinical application.One hundred and twenty patients scheduled for elective abdominal surgery under general anesthesia were randomly divided into four groups:control group(group C), dexmedetomidine group(Group S), dezocine group(Group D), and dexmedetomidine combined with dezocine group(Group SD), 30 patients in each group. Four groups of patients were treated with combined intravenous inhalational anesthesia. Anesthesia was maintained with continuous infusion of remifentanil at 0.2 μg·kg-1·min-1combined with sevoflurane that titrated to autonomic responses. 30 mins before the end of operation, group S, D and SD intravenously received dexmedetomidine 0.5 μg·kg-1, dezocine 0.1 mg·kg-1, dexmedetomidine0.5 μg·kg-1plus dezocine 0.1 mg·kg-1, respectively. All the medication was diluted to 30 ml, while group C received an equal volume of saline.The infusion time was 10~15 mins.The operation time, emergence time and extubation time were recorded. Changes of heart rate(HR), mean arterial pressure(MAP) and Rasmay sedation scores before extubation(S1), at the time of extubation(S2)and 10 mins after extubation(S3) were observed and recorded. VAS scores at 1 h(T0), 2 h(T1), 4 h(T3), 6 h(T4), 12 h(T5), 24 h(T6) after surgery were recorded. Morphine 0.1 mg·kg-1was injected intravenously after operation if needed. VAS scores were maintained≤3. The use of morphine andadverse effects during 24 h after operation were recorded.The results show that: ① There was no significant difference in age,gender, body mass index, operation time, emergence time, extubation time and remifentanil consumption(P>0.05). ② Compared with S1, HR, MAP at S2, S3 in group C and D were significantly increased(P<0.05), and HR,MAP at S2, S3 in group C and D also significantly higher than group S and SD(P<0.05). HR, MAP were stable at S1-S3 in group S and SD without significant difference(P>0.05). Rasmay scores in group S and SD were significantly higher than group C and D(P<0.05). ③ The VAS scores of group S, D and SD at T0~T3 were significantly lower than Group C(P<0.05), the VAS scores of group SD at T0~T3 were significantly lower than group S and D(P<0.05), the VAS scores of group D at T0~T3 were significantly lower than Group S(P<0.05), the VAS scores at T4,T5 did not indicate a significant difference among 4 groups(P>0.05). ④ The morphine consumption within 24 h after operation: group C had the most(P<0.05),group SD had the least(P<0.05), group S and D had the more,and group S more than group D(P<0.05). The cases of analgesic of group SD were lower than that in the other three groups(P<0.05). ⑤ The incidences of postoperative nausea and vomiting,shivering were higher in group C than that in the other three groups(P<0.05). No respiratory depression was happen in four groups.From results, the following conclusions can be drawn:①Dezocine is better at alleviating postoperative hyperalgesia induced by reminfentanil than dexmedetomidine.②Dexmedetomidine can better stabilize the circulatory system than dezocine.③The combination of the two agents has better efficacy than either alone without increasing the side-effects.