體外循環心臟不停跳之冠狀動脈繞道手術中雙頻指數值與實際麻醉深度之間的差異：來自腦電波訊號分析的見解

Discrepancy Between Bispectral Index Values and Actual Anesthesia Depth Dur-ing On-Pump Beating-Heart Coronary Artery Bypass Grafting: Insights From an Electroencephalography Signal Anal-ysis

體外心肺循環的獨特病生理效應可以改變麻醉藥物的藥物動力學和藥效學，增加術中意外甦醒的風險，這是心臟手術中罕見但災難性的併發症。 麻醉醫師常依靠雙頻指數來確保適當的麻醉深度； 然而，不同麻醉劑表現出明顯不同的腦電波特徵，因此對雙頻指數的影響也各異。在此，我們報告一位在體外心肺循環下進行心臟不停跳之冠狀動脈繞道手術的58 歲患者，其體外心肺循環期間使用咪達唑侖和吩坦尼來維持麻醉。奇特的是，儘管給予更高的劑量，雙頻指數仍然持續高於目標範圍，並與觀察到的臨床表現不一致。但在給予小劑量的異丙酚後，雙頻指數卻劇烈而不成比例地下降。雙頻指數與實際麻醉深度之間的差異促使我們詳細探討該病患的腦電波訊號。結果我們在功率譜密度上觀察到與異丙酚相關的微妙變化，這強調在解讀雙頻指數時需同時謹慎考慮臨床狀況和所使用之藥物的重要性。我們的結果將有助於改善複雜心臟手術期間的麻醉照護。

 

The unique pathophysiological effects of cardiopulmonary bypass can alter the pharmacokinetics and pharmacodynamics of anesthetics, increasing the risk of in-advertent intraoperative awareness, a rare but devastating complication of cardiac surgery. Anesthesiologists commonly rely on the bispectral index (BIS) to ensure appropriate anesthesia depth; however, different anesthetics exhibit distinct electro-encephalogram (EEG) signatures, thereby influencing BIS values differently. Herein, we present the case of a 58-year-old patient undergoing on-pump beating-heart cor-onary artery bypass grafting (CABG) and the anesthesia was maintained with mid-azolam and fentanyl during cardiopulmonary bypass. We observed a peculiar phe-nomenon that despite administering higher doses, BIS values remained above our target range. This elevation in BIS values was inconsistent with the observed clinical manifestations. After the administration of a very small dose of propofol, the BIS decreased dramatically and disproportionately. The discrepancy between BIS values and actual anesthesia depth prompted a detailed exploration of the patient’s EEG patterns. We observed a subtle alternation in the power spectral densities of EEG signals associated with propofol administration, which emphasizes the importance of interpreting BIS values with caution, considering the clinical context and medica-tion. Our findings may facilitate the improvement of anesthesia care during complex cardiac procedures.