靶控输注异丙酚复合瑞芬太尼用于重症肌无力患者胸腺切除时瑞芬太尼最佳切皮浓度的选择

The concentration of remifentanil at the time of skin incision with target controlled propofol-remifentanil infusion in myasthenia gravis patients undergoing thymectomy

目的探讨重症肌无力患者在不使用肌松药的情况下,靶控输注瑞芬太尼复合异丙酚进行胸腺切除手术,切皮时瑞芬太尼的适宜浓度。方法择期拟行胸腺切除术的重症肌无力患者45例,ASAⅠ或Ⅱ级。麻醉诱导:靶控输注异丙酚和瑞芬太尼,在2%利多卡因进行气管内表面麻醉后行气管插管,进行机械通气。切皮时将患者分为三组,每组15例,设定异丙酚血浆靶浓度为3.5μg/ml,瑞芬太尼效应室靶浓度分别为2ng/ml(R2组)、4ng/ml(R4组)、6ng/ml(R6组)。术中调节异丙酚血浆靶浓度,维持BIS40～60;调节瑞芬太尼效应室靶浓度,维持血压波动幅度在基础血压的20%～30%。术毕拔除气管导管或带管回监护病房。记录切皮前异丙酚及瑞芬太尼用药总量、切皮时患者是否有体动,切皮前和切皮后1min、2min、3min的心率(HR)、收缩压(SBP)、舒张压(DBP)、BIS的数值,麻醉诱导期间和切皮时心血管事件的发生情况。结果切皮时R2组有6例患者体动,与其他两组比较有统计学差异(P<0.05)。血流动力学变化,与切皮前比较R2组切皮后1min的SBP、DBP、HR明显高于切皮前的数值(P<0.05),R6组切皮后2min和3min的SBP及HR明显低于切皮前的数值(P<0.05)。切皮时R6组有3例患者发生心动过缓,对症处理后恢复正常。结论重症肌无力患者在不使用肌松药的情况下,在异丙酚血浆靶浓度为3.5μg/ml时,瑞芬太尼切皮的效应室靶浓度应为4ng/ml。

Objective To determine the target effect-site concentration of remifentanil at skin incision combined with propofol without muscle relaxant in myasthenia gravis(MG) patients for thymectomy.Methods 45 ASA Ⅰ or Ⅱ MG patients undergoing thymectomy were studied.Combined with the topical anesthesia of endotrachea by 2% lidocaine 2-3 ml,anesthesia was induced with propofol and remifentanil given by TCI and patients were intubated,then IPPV.45 patients were allocated to three groups,15 in each group:the patients received remifentanil target effect-site concentration of 2 ng/ml,4 ng/ml and 6 ng/ml(group R2,R4,R6),combined with propofol plasma concentration(Cp) 3.5 μg/ml.During operation plasma site concentration of propofol was adjusted according to bispectral index (BIS),and the effect site concentration of remifentail was adjusted according to blood pressure (BP).The BIS was maintained between 40 to 60,and the BP was maintained within the 20%-30% of baseline values.The following parameters were recorded at just before skin incision,1,2 and 3minutes after skin incision:systolic blood pressure(SBP),diastolic blood pressure(DBP),heart rate(HR),BIS values and motor responses to skin incision.The dosage of propofol and remifentanil was recorded before skin incision.Results Body movement occurred in 6 patients during skin incision.SBP,DBP and HR in group R2 increased significantly at 1min after skin incision(P<0.05).SBP and HR at 2 and 3min after skin incision were decreased significantly in group R6 (P<0.05).Bradycardia developed in 3 patients and hypotension in 4 patients during induction,but they all returned to normal after symptomatic treatment.Bradycardia developed in 3 patients during skin incision,but returned to normal after symptomatic treatment.Conclusions When plasma concentration of propofol is 3.5 μg/ml,the optimal effect-site concentration of remifentanil is 4 ng/ml at skin incision without muscle relaxant.