Research title : Objective asesssment of anesthetic depth under general anesthesia and conscious sedation using BIS monitor

双谱指数（BIS）监测用于评估麻醉过程中的麻醉深度，本研究研究了靶控输注PPF后的遗忘效应、估计异丙酚（PPF）的脑浓度和BIS值。[实验1]作为基础实验，我们研究了PPF给药时BIS值与PPF脑浓度估计值之间的关系，发现BIS值与脑浓度估计值存在相关性。然而，基于BIS值评估意识和失忆水平被证明是不可能的。[实验2]观察PPF在镇静诱导和觉醒过程中的遗忘作用。诱导时，估计脑内浓度为0.91±0.21μg/ml，唤醒时，估计脑内浓度为0.65±0.18μg/ml，获得遗忘效果。因此，在镇静状态下，较低浓度的PPF比诱导能维持更多的遗忘效果。[实验3]在PPF给药后苏醒期间，观察苏醒刺激对BIS值和镇静后遗忘效应的影响。结果表明，PPF给药后，如果主动给予唤醒刺激，BIS值会迅速增加。当给予唤醒刺激时，尽管估计PPF的大脑浓度很高，但遗忘效应消失，记忆恢复。然而，记忆恢复所需的BIS值范围很广，并且没有观察到一致的趋势。[实验4]在计划全麻的患者中，为了确定预用药对术前BIS值和记忆的影响，在患者进入手术室时评估BIS值和遗忘效果。结果显示，不同用药前的BIS值和遗忘效果存在显著差异。这表明BIS监测器在评估用药前也很有用。少

The Bispectral Index (BIS) monitor is used to assess anesthetic depth during anesthesia, and the present study investigated amnestic effects, estimated cerebral concentration of propofol (PPF), and BIS value following PPF administration by target control infusion.[Experiment 1] As a basic experiment, the relationship between the BIS value during PPF administration and estimated cerebral concentration of PPF was investigated, which revealed that a correlation existed between the BIS value and estimated cerebral concentration. However, the assessment of consciousness and amenesia levels based on the BIS value proved impossible.[Experiment 2] The amnestic effects of PPF during sedation induction and awakening were investigated. During the induction, amnestic effects were obtained at an estimated cerebral concentration of 0.91±0.21μg/ml, and during awakening, amnestic effects were obtained at an estimated cerebral concentration of 0.65±0.18μg/ml. Therefore, when under sedation, amnestic ef … More fects could be maintained at a lower concentration of PPF when compared to induction.[Experiment 3] During awakening following PPF administration, the effects of awakening stimulation on BIS value and post-sedation amnestic effects were investigated. The results showed that there was a rapid increase in BIS value if awakening stimulation was actively delivered after PPF administration. When awakening stimulation was delivered, although the estimated cerebral concentration of PPF was high, amnestic effects were lost and memory was regained. However, the BIS value required for memory recovery ranged widely, and no consistent tendencies were observed.[Experiment 4] In patients who were scheduled to undergo general anesthesia, in order to ascertain the effects of pre-medication on preoperative BIS value and memory, BIS value and amnestic effects were assessed upon the patient's entry in the operating room. The results showed significant differences in BIS value and amnestic effects among the different types of pre-medication. This suggests that the BIS monitor is also useful in assessing pre-medication. Less