腰-硬联合麻醉患者异丙酚不同镇静深度下半数有效的浓度、脑电双频指数和听觉诱发电位指数

EC_(50) of propofol by target-controll infusion,BIS_(50) and AAI_(50) for different levels of sedation during combined spinal-epldural anesthesia

目的测定腰-硬联合麻醉期间异丙酚靶控输注清醒镇静时患者不同镇静深度的半数有效浓度(EC50)、半数有效BIS(BIS50)和半数有效AAI(AAI50)。方法择期腰-硬联合麻醉下行下腹部或下肢手术患者45例,ASAⅠ级。腰麻阻滞完善后,异丙酚靶控输注清醒镇静,以患者OAA/S评分为镇静指标,采用二项Logistic回归方法计算不同镇静深度(OAA／S评分)的EC50、BIS50和AAI50。结果患者OAA/S4分时EC50为0.6μg／ml、BIS50为85和AAI50为72,OAA/S3分时EC50为1.0μg/ml、BIS50为75和AAI50为59,OAA／S2分时EC50为1.3μg/ml、BIS50为67和AAI50为39,OAA/S1分时EC50为1.6μg／ml、BIS50为61和从AAI50为30,OAA／S0分时EC50为2.5μg／ml、BIS50为41和.AAI50为12。结论EC50、BIS50和AAI50对患者腰-硬联合麻醉期间清醒镇静有重要的临床指导价值。

Objective To measure the EC50 of propofol administered by target-controll infusion(TCI) and BIS50 and AAI50 for different levels of sedation during combined spinal-epidural anesthesia (CSEA). EC50 , BIS50 and AAI50 were defined as the effective target effect-site concentration of propofol and BIS and AAI values at which different levels of sedation were achieved in 50% of patients.Methods Forty-five ASA Ⅰ patients (37 males, 8 females) aged 16-60 yr weighing 35-86 kg undergoing lower abdominal or lower limb surgery under CSEA were studied. CSEA was performed at L2-3 or L3-4 interspace. 0.75% bupivacaine 2 ml (15 mg) was injected into CSF. Intermittent boluses of 2% lidocaine were given through the epidural catheter during operation when needed. The average level of spinal block was T8 (T6-10 ) . The patients were sedated with propofol given by TCI. The level of sedation was assessed using observer assessment of the alertness/sedation scale (OAA/S) . BIS, AAI, MAP, ECG, HR, RR and SpO2 were monitored during anesthesia. Binary logistic regression was used to estimate the population values for EC50 BIS50 and AAI50 at different OAA/S scores. Results The EC50 of propofol from the score of 4-1 on the OAA/S scale were 0.6, 1.0, 1.3 and 1.6 μg·mi-1 ; the BIS50 values 85, 75, 67 and 61 and AAI50 values 72, 59, 39 and 30 respectively. Conclusion EC50 of propofol given by TCI, BIS50 and AAI50 for different levels of sedation were measured during operation under CSEA and are useful for maintaining conscious sedation during CSEA.