利用心跳的加速和減速能力探討麻醉中自律神經活性的變化

Abstract

一、研究背景與目的： 運用phase-rectified signal averaging (PRSA) 的方式分析心率變異性，可以反映出心跳的加速和減速能力 (acceleration capacity and deceleration capacity)。本研究在探討全身麻醉及手術刺激對心跳的加速和減速能力的影響，並輔以去趨勢波動分析法 (detrended fluctuation analysis, DFA) 的短期指標α1和傳統線性分析的方式，進一步了解其對自律神經調節的生理意義。 二、研究方法 我們選40位美國麻醉醫學會生理狀態分級第一級或第二級，預定接受常規手術的成人病患受試者。為了觀察不同的手術刺激影響，我們按照手術術式分成 (1) 一般手術組 (n = 40)，(2) 腹腔鏡手術組 (n = 27)。麻醉誘導皆使用2 μg/kg fentanyl、propofol靶控靜脈輸液 (目標作用濃度Cet為4.0 μg/mL )，和0.15-0.2 mg/kg cisatracurium；腹腔鏡手術組維持氣腹壓力15 mmHg進行手術。利用PRSA分析、去趨勢波動分析、時域分析以及頻域分析下列時期的心率變異性：(1) 清醒：基準值；(2) 麻醉期：全身麻醉後；(3) 手術期 (一般手術組)；氣腹期 (腹腔鏡手術組)。 三、結果 研究結果發現，麻醉期和清醒期相比，全部受試者的心跳減速和加速能力皆下降；DFA α1、高頻功率、低頻功率、以及時域分析的結果皆下降。一般手術組在手術期和劃刀前相比，僅DFA α1、心跳間期標準差、低頻功率、常規化低頻功率比、和低高頻功率比上升，但常規化高頻功率比下降。腹腔鏡手術組在氣腹期和麻醉期相比，心跳減速和加速能力、DFA α1、心跳間期標準差、低頻功率、常規化低頻功率比、和低高頻功率比上升、和高頻功率皆上升，但常規化高頻功率比下降。 四、結論 在全身麻醉之後，心跳的減速和加速能力與清醒相比皆顯著降低，顯示自律神經調節能力受到影響而造成心跳的加速和減速能力降低。此外，在相同的麻醉深度下，腹腔鏡手術中的氣腹會活化自律神經系統而造成心跳加速和減速的能力增加。

Background: Phase-rectified signal averaging (PRSA) is a new technique to separately characterise deceleration and acceleration of heart rate (DC/AC). To assess the effects of general anesthesia and surgical stimulation on the autonomic nervous system, deceleration and acceleration capacityof heart rate, detrended fluctuation analysis (DFA), and traditional linear analysis were used to evaulate sympathetic and parasympathetic control of heart-rate variability. Method: In this study, 67 unpremedicated adult patients who underwent elective surgery were anesthetized with propofol target-controlled infusion (Ce = 4.0 μg/ml). The status of cardiac autonomic nervous activity was evaluated by heart rate variability for three times: once whe the patient was awake, once after induction of general anesthesia, once after surgical excision(in general surgery group) or after insufflation for pneumoperitoneum (in laparoscopic surgery group). Intraabdominal pressure was maintained at 15 mmHg by a carbon dioxide insufflator. For each measurement, electrocardiogram was recorded for 600 second and played back offline to detect R-R intervals. PRSA was applied, and the acceleration and deceleration capacity were obtained. A short-term fractal scaling exponent (α1) analyzed by DFA method, time-domain analysis and power spectral analysis were also assessed.. Results: The DC, AC, fractal scaling index α1 , power of high frequency, lower frequency, and standard deviation of normal to normal (SDNN) decreased during the anesthetized stage, and increased during the pneumoperitoneum stage. The ratio of low-frequency power to high-frequency power (LF/HF) increased after induction of pneumoperitoneum. Conclusion: Our results suggest that general anesthesia decreases DC and AC, which represent the tonic autonomic modulation of heart rate variability. Moreover, pneumoperitoneum increased cardiac autonomic activity, and thus increased DC and AC.