Clinical Evaluation of Anesthetic Depth Monitoring with SNAP Index during Total Intravenous Anesthesia with Remifentanil and Propofol by Target-controlled Infusion<?XML:NAMESPACE PREFIX = O />

ABSTRACT

Objective：To evaluate the feasibility and efficacy of SNAP index as a means of anesthetic depth monitoring during total intravenous anesthesia (TIVA) with remifentanil and propofol by target-controlled infusion(TCI).
Methods：Sixty ASA Ⅰ～Ⅱpatients, aged 21～65yr,  were scheduled to undergo  elective laparoscopic cholecystectomy. All patients were randomly allotted into three groups of 20 patients each: SNAP index，BIS and control group. Anesthesia was induced with remifentanil 4ng•ml^-1 (effect-site concentrations, Ce), propofol 3μg•ml^-1 (Ce) and rocuronium 0.6mg•kg^-1. After tracheal intubation, the target concentrations of remifentanil kept constant, whereas propofol infusion was adjusted according to clinical parameters or target values: SNAP index set at 55 or BIS set at 50.The target values were adjusted to 65 for SNAP or 60 for BIS 15 min before skin closures. The changes of SNAP or BIS values, HR, and MAP were observed during anesthesia. Recovery times were recorded, and average normalized propofol, remifentanil and rocuronium consumption were calculated from induction and maintenance doses.
Results：There were no significant differences in duration of anesthesia， mean rocuronium and remifentanil dosages among three groups(p>0.05). Compared with control group, patients with SANP index or BIS monitoring needed significantly less propofol (C group 6.7±1.1mg•kg^-1•h^-1 vs. S group 4.3±1.2mg•kg^-1•h^-1 or B group 4.4±1.1mg•kg^-1•h^-1 , p<0.001), opened their eyes earlier (10.2±3.8min vs. 4.3±1.1min or 4.5±2.8min; p<0.001), and were extubated sooner (15.5±1.8min vs. 9.6±1.3min vs.10.3±1.5min; p<0.001). MAP and HR values at various time points during anesthesia were comparable for three groups (p>0.05). But hypotension incidence was significant higher in C group than in S group or B group (p<0.01). All patients were followed-up in the ward after surgery, and nobody had experienced intraoperative awareness. Conclusions: The results indicate that SNAP index is effective as BIS to significantly reduce propofol consumption, maintain hemodynamic stable and reduce recovery time compared with standard clinical practice.
Key words：Electroencephalogram; Target-controlled infusion; Anesthesia, intravenous；Anesthesia, depth；Propofol；Remifentanil

资料与方法<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

1. 一般资料
　　选择ASAⅠ～Ⅱ级，在全麻下行腹腔镜胆囊切除手术患者60例，年龄21～65岁。根据麻醉深度监测手段不同，随机分为三组：S组(用SNAPTM监测)，B组(用BIS监测)，C组(用常规方法监测),每组20例。精神异常、高血压患者、体重指数(body mass index, BMI=kg/m2)≥30者剔除。
2. 靶控配置
　　TCI系统主要由DELL P-IV 笔记本电脑(双串行输出口COM1、COM2)、Graseby 3500泵(两台)及相应的RS232端口组成。统一使用BD 50ml注射器，最大输注速度1200ml/h，分别输入丙泊酚(阿斯利康公司，批号：BM111)和瑞芬太尼(湖北宜昌人福制药公司，批号：030801)。靶控软件采用南非Stelpump 1.07version，Propofol 选用Marsh 药代模式，Remifentanil选用 Minto药代模式。
3. 监测项目
　　BIS、HR、SpO₂、SBP、MAP、DBP(HDX-Ⅰ型多功能监测仪，黑龙江华翔公司)；SNAP Index (Nicolet Biomedical 公司)；TOF(TOF-WatchTM, Organon公司)；PETCO2(芬兰Datex Ultima)。
4. 观察指标
　　观察全麻诱导插管期、维持期及恢复期的循环功能变化、SNAP指数或BIS的改变，并记录麻醉恢复时间、麻醉时间及麻醉药用量。
5. 麻醉方法
　　术前30min常规肌注鲁米那钠0.1g、东莨菪碱0.3mg。病人入室后于左上臂大静脉建立输液通道，于诱导前预充平衡液7ml/kg，术中以10ml•kg^-1•h^-1速率维持。麻醉深度监测仪各电极安放参考该公司推荐的标准方法联接。诱导开始先TCI 瑞芬太尼(Ce 定为4ng•ml^-1)，1min后，接着TCI 丙泊酚(Ce定为3μg•ml^-1)，意识消失后面罩给纯氧，3min后静注0.6mg/kg 罗库溴铵，1.5min后气管插管，行机械控制呼吸。机控呼吸频率10次/min，潮气量10ml/kg，术中PETCO₂ 维持在35～40mmHg。插管后瑞芬太尼浓度维持不变，而丙泊酚浓度则根据麻醉深度指数(SI= 55或BIS=50)或临床参数(MAP)进行调节，按每4min 增减0.5μg/ml。术中以罗库溴铵5～10μg?kg^-1•min^-1维持肌松并根据TOF(T1<10%)调节输注速率，术毕肌松恢复水平要求至少达到T4/T1≥25%。术毕前15min调节丙泊酚使SI至65或BIS至60。术毕停止TCI。术中低血压(SBP<30%基础值或SBP<80mmHg)静注麻黄素10mg；心率缓慢(HR<50bpm)静注阿托品0.25mg。术毕常规拮抗肌松(新斯的明1～2mg，阿托品0.5～1mg)。
6.　统计分析
　　应用统计软件SPSS10.0分析数据。计量资料：数据以均数±标准差(x±s)表示，比较采用student t检验，组间多重比较采用ANOVA(LSD,最小显著差异法) ；计数资料采用双侧χ2检验，p<0.05认为差异有统计学意义。

结　果<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

1. 一般情况
三组病人一般情况及麻醉时间、瑞芬太尼及罗库溴铵用量差异无统计学意义（表1，2）。与C组比较，S组和B组丙泊酚用量明显减少：S组为4.3±1.2mg•kg^-1•h^-1，B组为4.4±1.1mg•kg^-1•h^-1，C组为6.7±1.1mg•kg^-1•h^-1 (p<0.001)。S组和B组恢复时间较C组明显缩短，其睁眼时间分别为4.3±1.1min 、4.5±2.8min 、10.2±3.8min；拔管时间分别为9.6±1.3min、10.3±1.5min 、15.5±1.8min(p<0.001)。C组需升压药处理的病例明显多于S组和B组（p<0.01）。

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