建立類神經網路模型以預測propofol用於麻醉誘導時所產生的睡眠效應

Neural Network Modeling to Predict the Hypnotic Effect of Propofol Bolus Induction

林朝順(Lin Chao-Shun)

指導教授 ： 李友專

臺北醫學大學/醫學院/醫學資訊研究所/碩士(2002年)

摘要

Propofol的臨床劑量需求，決定於個別病人的特異性，以及併用藥物的交互作用。當以單次劑量給予propofol以達到麻醉誘導目的時，如何計算個別病人的最佳劑量，以及此劑量是否完全適合於此位病人，至目前為止一直沒有明確地被研究。本篇論文的目的，希望以普遍可得的臨床參數為基礎，訓練一類神經網路模型，此模型可根據個別病人的特異性，對於利用propofol實行麻醉誘導時，所達到的睡眠效應是否足夠做出預測。 預定在靜脈麻醉下接受常規手術的病人，共兩百七十位成為我們的研究對像。根據相關的醫學文獻以及過去的臨床經驗，總共十項參數，包括propofol劑量，病人的年齡性別，身高體重等等，被選定為訓練類神經網路的輸入參數。我們使用畢斯腦波指數（bispectral index）監測病人的意識清醒程度，用以判斷propofol的造成的睡眠效應，並以此做為網路訓練的輸出參數。以一百八十位病人的資料用來訓練類神經網路，完成兩種不同架構的模型之後，再以另外未參與訓練的九十組病人資料，來測試此模型的效能。三位資深麻醉醫師對於propofol的睡眠效應的預測結果，將和類神經網路模型的結果做比較。 類神經網路模型之一的standard networks，對於測試組資料的sensitivity為76.19 %，specificity為65.22 %，而另外一種網路架構Ward networks則分別為80.95 %和57.97 %。臨床麻醉醫師的預測結果，sensitivity為23.81 %，specificity為91.30 %。兩種類神經網路模型得到的結果，繪製出ROC曲線，曲線下面積分別為0.7552和0.7272。 在計算propofol的劑量需求時，個別病人的特異性應列入考慮，但是在目前的臨床醫學卻無法確實做到。在此篇論文中，我們訓練了類神經網路模型，針對病人的不同特性，來預測propofol的麻醉效應，最後得到的結果雖然優於臨床醫師，但仍然不盡理想。包含心輸出量，中心血液容積等幾項重要的因素無法被加入訓練，應是主要的原因。未來應可以此實驗架構為基礎，增加收錄的樣本數，以及加入重要的決定性因素，如此應能進一步強化類神經網路模型的預測能力，未來可做為臨床醫師在決定propofol劑量時的決策輔助。

關鍵字

麻醉 ； 類神經網路 ； 畢斯指數 ； propofol

並列摘要

Dose requirements of propofol to achieve loss of consciousness depend on the interindividual variability and on the interaction with other concomitant medication. Until now when propofol was administrated by a single bolus, how to define the optimal individual dose and to investigate its hypnotic effect have not been clearly studied. The goal of this study is to develop an artificial neural network model on the basis of common clinical parameters. We would demonstrate its ability in predicting the hypnotic effect of propofol bolus induction and compare the network output to clinician’s prediction. Two hundred and seventy patients undergoing elective surgery under total intravenous anesthesia were enrolled into this study. Ten parameters were chosen as the input factors based on the related literatures and clinical experiences. The bispectral index of EEG was used to record the consciousness level of patients and served as the output factor. The predictive model derived from the artificial neural network was validated on an entirely different data set that was not included in the training set. The architectures selected in this study were the standard nets and the Ward nets using the NeuroShell 2 software system. Three senior anesthesiologists in our department would make predictions of validation set according to the chosen input factors. The results would be compared to those of trained artificial neural networks. The standard nets had a sensitivity of 76.19 % and a specificity of 65.22 %. The ward nets had a sensitivity of 80.95 % and a specificity of 57.97 %. The clinician made prediction for the 3rd min BIS >60 with a sensitivity of 23.81 % and a specificity of 91.30 %. The area under ROC curve for the standard nets and ward nets were 0.7552 and 0.7274 respectively. The predictive results of neural net models were superior to that of clinician. When calculating the dose requirement of propofol, we should consider the individual condition of each patient. In this study we constructed the artificial neural network model to predict the 3rd min of anesthesia depth under propofol bolus induction. In the future we could enhance the sensitivity and specificity by adding more important parameters. The dosing support system of propofol might be accomplished on the basis of this model to provide the optimal bolus dose to achieve the ideal induction endpoint. This model can potentially help determine the optimal dose of propofol and thus reduce the anesthetic cost.

並列關鍵字

anesthesia ； neural networks ； Bispectral index ； propofol

參考文獻

Homer TD, Stanski DR The effect of increasing age on thiopental disposition and anesthetic requirement. Anesthesiology 1985;62:714. Hug CC Jr, McLeskey CH, Nahrwold ML, Roizen MF, Stanley TH, Thisted RA et al. Hemodynamic effects of propofol: data from over 25,000 patients. Anesth Analg 1993;77(4 Suppl):S21-9.

Abeles G, Sequeira M, Swensen RD, Bisaccia E, Scarborough DA. The combined use of propofol and fentanyl for outpatient intravenous conscious sedation. Dermatologic Surgery 1999;25(7):559-62.

Adachi YU, Watanabe K, Higuchi H, Satoh T. The determinants of propofol induction of anesthesia dose. Anesth Analg 2001;92(3):656-61.

Albanese J, Martin C, Lacarelle B, Saux P, Durand A, Gouin F. Pharmacokinetics of long-term propofol infusion used for sedation in ICU patients. Anesthesiology 1990;73(2):214-7.

Arden JR, Holley FO, Stanski DR. Increased sensitivity to etomidate in the elderly: initial distribution versus altered brain response. Anesthesiology 1986;65:19. Arnold BD. Sedation with propofol during regional anaesthesia. Br J Anaesth 1993;70(1):112.