摘要
目的 通过监测脑电双频指数和心率变异功率谱,评价硬膜外麻醉后对异丙酚镇静催眠剂量的影响,并探讨其可能的机制。方法 50例行全子宫切除病人,随机分为硬膜外利多卡因组（GE,n=15）;硬膜外盐水-静脉利多卡因组（GI=15）;硬膜外盐水-静脉盐水组（GC=20）。硬膜外或静脉给利多卡因 20 min后,连续输注异丙酚至神志消失并记录异丙酚用量。所有病人同时监测脑电双频谱（BIS）、心率变异高频功率谱（HF）、低频功率谱（LF）、心电图和血压。输注异丙酚前抽取桡动脉血 2ml,测定血浆利多卡因浓度。结果 病人意识消失时异丙酚用量分别为GE组（1.22±0.25）mg/kg;GI组（1.62±0.22）mg/kg;GC组（1.85±0.41）mg/kg（GE与GI和GC比,P<0.05）。GE组和 GI组血浆利多卡因浓度分别为 3.04 μg/ml和 2.45 μg/ml,无统计学差异。三组病人意识消失时BIS平均值分别为54.4、57.1、55.3。结论 硬膜外利多卡因阻滞可降低异丙酚用量约35％。其作用机制与利多卡因自硬膜外吸收后的中枢镇静作用无明显关系,而可能与硬膜外阻滞后间接引起中枢兴奋阈值降低有关。
Objective To investigate the potential sedative effects of epidural anesthesia and its mechanism. Methods Fifty ASA Ⅰ -Ⅱ patients aged 20-55yr, scheduled for gynecological surgery were studied. Patients whose body weight exceeded 95 kg or was less than 45kg were excluded. Alcoholics and those addicted to sedative or opiates were also excluded. The patients were unpremedicated. Before anesthesia the patients' radial artery was cannulated for continuous BP monitoring and blood sampling. ECG, BIS and HRV were continuously monitored. Epidural puncture was performed at L1-2 . A catheter was inserted in epidural space for 3-4cm in a cephalad direction. The patients were randomly divided into 3 groups: epidural lidocaine group (group E, n = 15); intravenous lidocaine group (group Ⅰ , n = 15) and control group (group C, n =20). In group E the patients received an iv bolus of lidocaine 1.5mg·kg-1 followed by a lidocaine infusion at a rate of 30mg·kg-1·min-1 and an epidural bolus of normal saline 15 ml; in group C the patients received an epidural bolus of NS 15 ml only. The intravenous lidocaine infusion in group I was designed to mimic systemic absorption of lidocaine from epidural space. 20 min after epidural lidocaine or saline administration, a propofol infusion was started at a rate of 150ml/h until the patients lost consciousness, The amount of propofol infused was recorded. Blood samples were taken before propofol infusion for determination of plasma level of lidocaine. Results The amount of propofol infused when the patients lost consciousness was (1.22 ±0.25) mg·kg-1 in group E, (1.62 ±0.22) mg·kg-1 in group I and (1.85±0.41) mg·kg-1 in control group. The amount of propofol infused in group E was significantly less than that n group I and C ( P < 0.05 ) . The mean plasma concentration of lidocaine before propofol infusion was 3.04mg·ml-1 in group E and 2.45 mg·ml-1 in group I respectively. The difference was of no statistical significance. The mean BIS value was 54.4, 57.1 and 55.3 respectively when the patents lost consciousness. Conclusions Epidural anesthesia significantly reduces propofol requirement by 35% . The propofol sparing effect is most likely caused by indirect central effects of spinal deafferentation and not dueto systemic effects of lidocaine.
出处
《中华麻醉学杂志》
CAS
CSCD
北大核心
2002年第5期273-275,共3页
Chinese Journal of Anesthesiology
关键词
利多卡因
异丙酚
硬膜外阻滞
镇静作用
Anesthesia, epidural
Propofol
Lidocaine
Conscious sedation
