摘要
背景双频指数（bispectralindex，BIS）是一种被广泛用于评估麻醉和镇静水-y-的定量参数。右美托咪啶是一种新型镇静药，在提供镇静作用的同时患者能够保持合作且易唤醒。因此，应用右美托咪啶时BIS值可能不能准确反映镇静水平。因而，我们假设在警觉镇静评分（Observer’SAssessmentofAlertnessandSedation，OAA／S）相同的情况下，使用右美托咪啶时的BIS值低于丙泊酚，并对此假设进行验证。方法这是一项为期2天的随机交叉研究。健康志愿者于第一天随机接受丙泊酚或右美托咪啶镇静。利用计算机靶控输注，控制丙泊酚效应室浓度为1、2、4μg／ml，右美托咪啶血浆浓度为0．6、1．2和2．4ng／ml。每次改变药物浓度20分钟后、40分钟后，记录BIS与OAA／S评分的相互关系。比较每一OAA／S评分下两药的BIS值。通过对受试者操作特性曲线的分析得出OAA／S≤2时的BIS临界值。结果一共9名志愿者纳入本研究。右美托咪啶镇静时心率显著下降。大剂量丙泊酚引起ETCO，显著增加，而右美托咪啶则无此效应。丙泊酚镇静下，OAA／S评分为1、2、3、4、5时，BIS值分别为95．5（90。97）、78（71。84．5）、67（64—70）、57（51．5—60）和34（30—37）。右美托咪啶镇静下，OAA，s评分为1、2、3、4、5时；BIS值分别为95（79～98）、62（53．5—68．5）、45．5（45．3～52）、39．5（34．3—41．8）和24．5（22．5～30．5）。当OAA／S评分为2、3、4时，右美托咪啶的BIS值显著低于丙泊酚。丙泊酚和右美托咪啶镇静下OAA／S≤2分时的IBIS临界值分别为67（敏感度为86％，特异性为97％，曲线下面积0．98）和46（敏感度为84％，特异性为91％，曲线下面积0．96）。结论联合使用BIS和镇静评分较单独使用其中一项更能够为临床医生在评估患者镇静反应时提供不同的和互补的信息，尤其是应用右美托咪啶时。
BACKGROUND： Bispectral index （BIS） is a widely used quantitative parameter for evaluating anesthesia and sedation levels. Dexmedetornidine is a novel sedative, providing sedation while patients remain cooperative and can be easily aroused; as a consequence, BIS used with dexmedetomidine may poorly characterize sedation. Thus, we tested the hy- pothesis that BIS values are lower with dexmedetomidine than with propofol at comparable Observer＇s Assessment of Alert- ness and Sedation （OAA/S） scores. METHODS： This was a randomized, 2-day, crossover study. On the first study day, healthy volunteers were randomly allocated to either propofol or dexmedetomidine sedation. Drugs were administered using computer-controlled infusions targeting an effect-site concentration of 1,2, and 4 μg/ml for propofol or a plasma concentra- tion of 0.6, 1.2, and 2.4 ng/ml for dexmedetomidine. The relationship between BIS and OANS score was obtained 20 and 40 min after changing each drug concentration. BIS values at each OANS score were compared between drugs. The cutoff val- ues of BIS for OANS score of ≤2 were obtained by analysis of receiver operating characteristic curves. RESULTS： Nine vol- unteers were induded in our analysis. Heart rates decreased significantly with dexmedetomidine sedation. ETc% was signifi- cantly increased with high doses of propofol but did not increase with high doses of dexmedetomidine. BIS values at OAA/S scores of 1, 2, 3,4, and 5 during propofol sedation were 95.5 （90 - 97）, 78 （71 - 84.5）, 67 （64 - 70）, 57 （51.5 - 6Q）, and 34 （30 -37）, respectively. BIS values at OAA/S scores of 1,2, 3, 4, and 5 during dexmedetomidine sedation were 95 （79 -98）, 62 （53.5 - 68.5）, 45.5 （45.3 -52）, 39.5 （34. 3 -41.8）, and 24. 5 （22.5 -30. 5）, respectively. BIS values were significantly less with dexmedetomidine than propofol at OANS responsiveness scores of 2, 3, and 4. The calculated cutoff BIS values forOAA/S scores of≤2 were 67 （sensitivity of 86%, specificity of 97%, and area under the curve of 0. 98） for propofol and 46 （sensitivity of 84%, specifidty of 91%, and area under the curve of 0. 96） for dexmedetomidine. CONCLUSIONS： The com- bination of both BIS and sedative scales could provide different and complementary data to the clinician evaluating the pa- tient＇s response to sedation than would either tool alone, especially when dexmedetomidine is used.
出处
《麻醉与镇痛》
2011年第6期44-49,共6页
Anesthesia & Analgesia
