丙泊酚靶控输注复合雷米芬太尼麻醉期间右旋美托咪啶对麻醉深度的影响

目的: 研究丙泊酚靶控输注复合雷米芬太尼麻醉期间,右旋美托咪啶(Dex)对脑电双频谱指数(BIS)和听觉诱发电位指数(AAI)的影响.方法:选择拟于全麻下行甲状腺次全切除术的年轻患者30例(ASA Ⅰ～Ⅱ级),诱导方法:以血浆药物浓度为靶目标进行丙泊酚靶控输注,靶浓度(Ct)为4 mg/L,同时静脉泵注雷米芬太尼1 μg/kg,待患者意识消失后静注罗库溴铵0.6 mg/kg,1 min后气管内插管.术中以雷米芬太尼0.2 μg/(kg·min)~(-1) 维持麻醉,定时追加肌松药,调节丙泊酚靶控输注的Ct值,使BIS维持在50±3;维持10 min稳定后将患者随机双盲分为两组:D组(n=15):Dex 0.4 μg/kg,用生理盐水稀释成5 ml静脉泵注(5 min),C组(对照,n=15):生理盐水5 ml,方法同D组.记录20 min内BIS、AAI、MAP、HR.结果:D组静注Dex后BIS由51.4±2.2逐渐下降,20 min时降为42.2±15.7(P<0.05);而AAI给药前15.1±3.3,20 min内没有明显变化;C组对照观察期间BIS、AAI均无明显变化.结论:丙泊酚靶控输注复合雷米芬太尼麻醉稳定后,静注Dex能使BIS进一步下降,而AAI保持不变.

Effect of dexmedetomidine on bispectral index and auditory evoked potential index during anesthesia with target controlled infusion of propofol and remifentanyl

Objective: To evaluate the effect of dexmedetomidine (Dex) on bispectral index (BIS) and auditory evoked potential index (AAI) during anesthesia with target controlled infusion (TCI) of propofol and remifentanyl.Methods: Thirty adult patients (ASA I～II) who were scheduled for elective thyroidectomy were monitored with BIS,AAI,ECG,blood pressure,end-tidal CO_(2),and pulse oximeter before and during anesthesia.Anesthesia was induced by TCI with propofol 4 mg/L and remifentanyl 1 μg/kg.After loss of consciousness the patients were intubated after rocuronium 0.6 mg/kg intravenous injection,remifentanyl was then infused at 0.2 μg/(kg·min)~(-1) and propofol infusion (Ct) was titrated to maintain a BIS value at 50±3.At 10 min after stabilization of anesthesia the patients were randomly and double-blindly divided into 2 groups:Group D (n=15) received Dex 0.4 μg/kg iv administered over 5 min and Group C (n=15) received equal volume of normal saline.Values of BIS,AAI,MAP,HR were recorded every 2 min within 20 min after the administration of the drugs. Results: Before anesthesia the BIS index was 90±2 in Group D and 92±2 in Group C,AAI was 81±1 in Group D and 78±1 in Group C.In anesthesia with target controlled infusion of propofol,BIS index showed a significant decrease with the i.v.administration of Dex 0.4 μg/kg,while AAI remained unchanged.In Group C,both of BIS and AAI remained unchanged after saline injection. Conclusion: During propofol and remifentanyl anesthesia,after the administration of Dex,BIS value demonstrates a predominant decrease,whereas AAI shows no changes.