同等镇静深度下应用右美托咪定不能降低抑制切皮体动反应所需的瑞芬太尼用量

Systemic dexmedetomidine does not attenuate remifentanil requirements for inhibiting body movement at the similar sedative depth in propofol anaesthesia

目的：以体动反应为观察指标,观察相同的镇静深度下,右美托咪定的镇痛作用是否能降低术中镇痛药的使用量。方法：拟行乳房良性肿瘤切除术患者90例,随机分为3组：对照组、右美托咪定0.5μg/kg组（低剂量组）和右美托咪定1.0μg/kg组（高剂量组）,每组30例,分别输注生理盐水、右美托咪定0.5和1.0μg/kg,泵注持续时间为10 min,然后分别持续输注生理盐水和右美托咪定0.17、0.33μg·kg-1·h-1。效应室靶控输注丙泊酚,对照组、低剂量组和高剂量组初始浓度分别设定为2.5、1.5和0.5 mg/L,每隔3 min调节靶浓度直至患者对推摇无反应（OAA/S评分=1分）,然后效应室靶控输注瑞芬太尼。采用改良Dixon’s序贯法进行试验,各组瑞芬太尼初始靶浓度均设定为2.0μg/L,相邻浓度差值为0.2μg/L,靶控瑞芬太尼3 min后切开乳房皮肤5 cm,观察患者有无体动反应。绘制序贯图,体动反应转变成无反应的中点对应瑞芬太尼浓度的均值即为瑞芬太尼抑制切皮体动反应的半数有效效应室浓度（Ce50）。Ce50组间比较采用t检验并用Bonferroni法校正,P〈0.016 7为差异有统计学意义。结果：对照组、低剂量组和高剂量组瑞芬太尼抑制切皮体动反应的Ce50（95%CI）分别为1.43 ng/m L（1.33-1.53 ng/m L）、1.58 ng/m L（1.43-1.72 ng/m L）和1.53 ng/m L（1.36-1.69 ng/m L）,3组间Ce50差异无统计学意义（P〉0.016 7）。结论：全麻辅助应用右美托咪定时,在相同的镇静深度下术中抑制切皮体动反应所需的瑞芬太尼用量没有降低。

Objective： To observe the effect of analgesic action of dexmedetomidine（DEX） on perioper- ative opioid requirement using body movement as observation indicator at the similar sedative depth in propofol anaesthesia. Methods： Ninety patients were randomly allocated to one of three groups： control group（ group D0）, 0.5 μg/kg DEX group（ group DI ） and 1.0 μg/kg DEX group （group D2）. Saline and DEX 0.5 and 1.0 μg/kg were administrated intravenously for 10 minutes, followed by saline and dexme- detomidine at infusion rates of 0.17 and 0.33 μg/（kg · h） ,in DO, D1 and D2 group, respectively. After DEX and saline administration, patients received effect-site target-controlled infusion of propofol. Initially, the effect-site concentrations were set at 2.5, 1.5 and 0.5 g/mL in DO, D1 and D2 group, respectively. These were increased every 3 rain until OAA/S score reached to 1. When OAA/S = 1, an effect-site controlled infusion of remifentanil started. The concentration of remifentanil blunting body movement in response to skin incision in 50% of patients（Ces0） was determined using a modified Dixon＇s sequential up-and-down method. The concentration of remifentanil given to the patient was determined according to the response of the preceding patient. In all three groups, the initial concentration of remifentanil was set at 2.0 ng/mL and the test space was 0.2 ng/mL. Three minutes following remifentanil administration, a 5 cm incision was made by surgeon. Movement was defined as visible movement of body, limbs, head or neck. The C%0 （with 95% CI） of remifentanil was defined as the average of mid-point concentration of all independent pairs of patients who showed a cross-over fi-om ＇ movement＇ to ＇ no movement＇. The comparison of C%0 was per- formed using a Student＇s t test with Bonferroni correction. The significance level for this analysis was set at 0. 0167. Results： The C%0 （95% CI） of remifentanil blunting body movement were 1.43 ng/mL（ 1.33 - 1. 53 rig/mE） ,1.58 rig/mE（ 1.43 - 1.72 ng/mL） and 1.53 ng/mL（ 1.36 - 1.69 ng/mL） in DO, D1 and D2 group, respectively. There was no significant differences in C%0 between groups（P 〉 0. 0167）. Conclu- sion： Adjunctive dexmedetomidine does not attenuate remifentanil requirements for inhibiting body naove- ment at the similar sedative depth in general anaesthesia.