咪唑安定靶控输注时镇静深度的预测

Target plasma concentration,effect-site concentration and EEC analysis predict the depth of midazolam-induced sedation

目的 探讨咪唑安定 (MDZ)靶控输注镇静时目标血药浓度、效应室浓度与脑电指标双频指数 (BIS)、95 %边缘频率 (95 %SEF)预测镇静深度的临床价值及MDZ在区域麻醉靶控输注镇静中的适宜目标浓度。方法 选择ASAⅠ～Ⅱ级的择期手术患者 14例 ,以血药浓度作为靶控输注目标浓度。第一阶段靶浓度为 5 0ng/ml,继以 5 0ng/ml浓度梯度递增 ,每一阶段维持 15分钟 ,至镇静评分 (OAA/S评分法 )达 1分后停药 ,观察并双盲记录目标血药浓度、效应室浓度、BIS、95 %SEF、血液动力学和镇静评分各指标至患者清醒 ,用Spearman’s等级相关进行相关分析。 结果 镇静起效期(0AA/S5～ 1)OAA/S与BIS、95 %SEF、目标血药浓度、效应室浓度的相关系数分别为r =0 735、0 4 15、- 0 4 87和 - 0 6 89(P值均 <0 0 0 1)。镇静恢复期 (0AA/S1～ 5)分别为r =0 6 14、0 2 94、-0 5 5 1和 - 0 4 97(P值均 <0 0 1)。不同镇静评分时各指标变化有显著差异。血液动力学指标未见与镇静评分相关。结论 MDZ靶控输注镇静时 ,目标血药浓度、效应室浓度、BIS和 95 %SEF均可用于镇静深度的预测 ,镇静评分与BIS相关最好 ,镇静深度宜维持在OAA/S评分 2～ 3分 ,目标血药浓度 10 0ng/ml左右 ,BIS在 77～ 81之间。

Objective To investigate the relationship between the depth of midazolam induced sedation and the target plasma concentration(Cp),the effect site concentration(Ce) or electroencephalogram(EEG)parameters during regional anesthesia.Methods Fourteen ASAⅠ Ⅱ status patients scheduled for elective operations under regional anesthesia were studied.Patients were sedated by target controlled infusion of midazolam.Target plasma concentration was first set at a concentration of 50ng/ml and increased by 50ng/ml each grade until the patients became unresponsive to tactile stimulation.Each target concentration infusion was maintained for 15min.Sedation was assessed using the observers assessment of alterness/sedation(OAA/S) scale.Cp,Ce,EEG parameters and OAA/S score were recorded every 5min from the onset to the recovery of midazolam induced sedation.Nonparametric speasrmans rank correlation analysis was used for the correlation between OAA/S score and Cp,Ce or EEG parameters.Results During both the onset phases and the recovery phases OAA/S scores were correlated with the Cp(Spearmans Rho=-0 487, 0 551),the Ce(Spearmans Rho=-0 689,-0 497),BIS(Spearmans Rho=0 735,0 614) and 95%SEF(Spearmans Rho=0 415,0 294),respectively( P< 0 001).Conclusion The Cp,Ce,BIS and 95%SEF can all be used to monitor the depth of midazolam induced sedation,especially BIS.BIS value 77 81,Cp 100ng/ml or OAA/S score 2 3 are maintained so as to achive better sedation during regional anesthesia. [