Development of automatic infusion systems for sedatives and analgesics with surface EEGs and Auditory Evoked Potentials as Input Signals

该项目的目的是开发能够独立控制镇静剂和止痛剂的自动输液系统。我们选择表面EEG变量和听觉诱发电位作为输入信号来量化镇静和镇痛水平。我们进行了以下子研究来完成这个项目。1）丙泊酚和芬太尼的靶控输注（TCI）系统的开发利用已发表的药代动力学模型，2）建立了一个能独立控制异丙酚和芬太尼的血药浓度和效应部位浓度的脑靶控输注系统。以听觉诱发电位指数（AEPindex）和听觉诱发电位指数（AEPindex）作为表面脑电和听觉诱发电位的数值变量。3）异丙酚和芬太尼对脑电参数相互作用的研究我们研究了异丙酚和芬太尼对脑电的相互作用，以开发一种能够独立量化镇静和镇痛水平的算法。4）利用BIS和AEPindex检测意识的算法研究我们可以使用BIS和AEPindex的组合来更准确地检测意识5）深低温对脑电变量的影响我们研究了低至22 ℃时脑电变量的稳定性。我们发现AEP指数是最稳定的EEG变量中研究在深低温。总之，我们发现，表面EEG和听觉诱发电位的组合是有用的，以检测意识更准确，但组合没有足够的能力来量化镇痛水平。

The aim of this project was to develop automatic infusion systems which were able to control a sedative and an analgesic independently. We chose surface EEG variables and auditory evoked potentials as input signals to quantify levels of sedation and analgesia. We have performed following sub-studies to complete this project.1) Development of target controlled infusion (TCI) systems for propofol and fentanylUsing published pharmacokinetic models, we made up TCI systems which were able to control blood or effect site concentration of propofol and fentanyl independently.2) Development of a computer system to integrate surface EEG variables and auditory evoked potentialsBispectral Index (BIS) and auditory evoked potential index (AEPindex) were involved as numerical variables for surface EEG and auditory evoked potentials, respectively. BIS and AEPindex values were automatically recorded in the system.3) Investigation of the interaction of propofol and fentanyl on EEG variablesWe studied interaction of propofol and fentanyl on EEGs to develop an algorithm which could quantify level of sedation and analgesia independently.4) Investigation of an algorithm to detect awareness using BIS and AEPindexWe could detect awareness more accurately using a combination of BIS and AEPindex5) Effects of profound hypothermia on EEG variablesWe investigated stability of EEG variables down to 22 degree centigrade. We found the AEPindex was most stable among the EEG variables studied during profound hypothermia.In conclusions, we found that the combination of the surface EEG and auditory evoked potentials were useful to detect awareness more accurately, however the combination did not have enough ability to quantify level of analgesia.