以即時心率變異度分析系統探討麻醉之影響

PC-Based Real-Time HRV Analysis System for the Effect of Anaesthesia

蔡明曄(Ming-Ya Tsai)

指導教授 ： 徐良育

中原大學/工學院/醫學工程研究所/碩士(2001年)

https://doi.org/10.6840/cycu200100274

摘要

麻醉，是在外科手術中不可或缺的一環。但是過淺或過深的麻醉均會對病人造成不良的影響，而適度的麻醉深度不但節省麻醉藥物的使用，同時病人於麻醉後較容易回復。所以維持適度的麻醉深度一直都受到麻醉醫師以及外科醫師的深度關切。
在臨床上麻醉醫師依賴觀察病人的心血管、自主神經及軀幹的各種反應來決定麻醉的適度與否。而心跳速率（heart rate，HR）就是一個可以表現心臟血管健康情況的量化指標，許多生理上的反應機制皆會影響心跳速率或血壓的變化，複雜且龐大的生理循環系統及神經控制系統會影響心跳速率及血壓的恆定，而利用心率變異度的方法則可以反映出在麻醉過程中自主神經系統的反應機制。
所以，本研究嘗試建構出一套以PC為平台的即時心率變異度分析系統，以非線性Poincaré plots分析法與時頻域分析方法來顯示心率變異度。此系統之建立，目的在於即時觀察動態心率變異度變化並適時提供資訊，並針對ketamine與sevoflurane兩種常用的麻醉藥劑，評估其於實際麻醉過程中對自主神經系統產生的影響，以瞭解自主神經系統作用的機制。於是本研究設計兩組實驗，分別為對照組：傾斜床實驗，驗證本系統之可行性；實驗組：半身麻醉與全身麻醉過程，評估ketamine與sevoflurane與自主神經系統間的作用機制。
經由本系統分析並統計後得知，傾斜床實驗中，傾斜床傾斜後會使低頻能量與SD1上升，平躺後低頻能量與SD1下降，反映出系統對於交感神經活性之評估有一定正確率與靈敏度。且在Poincaré plots與時頻域分析法所得之參數相關度，得知LF與SD1、HF與SD2，LF/HF與SD1/SD2彼此間有相關性存在（p<0.05）。
此外，在麻醉藥劑特性上，ketamine在注射後使得心率上升，但卻會抑制交感神經末稍與神經外正腎上腺素的再吸收。Sevoflurane對於心率則不影響，但對於交感神經活性則會產生抑制作用，而且濃度的多寡、誘導時間的長短皆會影響抑制的效果。

關鍵字

sevoflurane ； ketamine ； 時頻域 ； Poincaré plots ； 心率變異度

並列摘要

Beat-to-beat heart rate variability (HRV) is caused by the fluctuating balance of sympathetic and parasympathetic tone at the sino-atrial node. Time domain summary statistics and frequency domain parameters can be used to measure heart rate variability. More recently, the Poincaré plots has been used to evaluate heart rate variability. The aim of this study was to develop a PC based heart rate variability analysis system that uses Poincaré plots (nonlinear analysis) and time-frequency analysis. First, tilting test had been performed to evaluate the sympathovagal balance. Second, the effects of two different anesthetics, ketamine and sevoflurane, on the heart rate variability were evaluated during anesthetic induction.
The low frequency (LF) power as well as the SD1 of the Poincaré plots increased while subjects were tilt up from the supine position. Additionally, highly significant correlation had been found between LF and SD1, HF and SD2, and LF/HF and SD1/SD2 (p value < 0.05).
Ketamine, a common used IV anesthetic for anesthesia and sedation, increase heart rate and blood pressure during anesthetic induction. However, LF and SD1 of Poincaré plots decreased significantly. Sevoflurane inhalation for 10 minutes had no effect on heart rate but diminished LF, total power and SD1, SD2 of Poincaré plots respectively. Either L/H ratio or SD1/SD2 ratio of Poincaré plots increased after intubation stimulation.
Poincaré plots and time-frequency analysis HRV has significant correlation during anesthetic induction. Compare with time-frequency analysis, Poincaré plot analysis is more easy and sensitive to evaluate the sympathovagal balance and to observe the beat-to-beat heart rate variability.

並列關鍵字

sevoflurane ； heart rate variability ； ketamine ； Poincaré plots ； time-frequency domain

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