建模與定量麻醉心電訊號裡的節律與非節律現象

Abstract

瞬時心跳速率的變化在麻醉深度較深時顯得規律振蕩，在麻醉深度較淺時則顯得較不規律。這個「律動至非律動」現象無法從目前標準麻醉監測儀器上的心電圖波形觀察到。為了探討可能的臨床價值，我提出「可適性諧波分析」模型，此模型符合生理上的特性，並提供足夠的數學條件以進一步定量化這個現象。基於此模型，我們可以使用multitaper Synchrosqueezing transform來實現時變功率頻譜，進而運算定量指標：「非律動至律動」指標(NRR指標)。之後我運用一個臨床資料庫來分析NRR指標的行為，並且將它與其它現行標準麻醉深度指標比較。統計結果顯示NRR指標可以提供額外的臨床資訊反映運動動作的反應，以並行於目前的標準工具。此外我還發現了對於手術傷害性刺激的指標。最後，我提出一個有助於將成果實用化的即時內插方案。

Variations of instantaneous heart rate appears regularly oscillatory in deeper levels of anesthesia and less regular in lighter levels of anesthesia. It is impossible to observe this ``rhythmic-to-non-rhythmic' phenomenon from raw electrocardiography waveform in current standard anesthesia monitors. To explore the possible clinical value, I proposed the adaptive harmonic model, which fits the descriptive property in physiology, and provides adequate mathematical conditions for the quantification. Based on the adaptive harmonic model, multitaper Synchrosqueezing transform was used to provide time-varying power spectrum, which facilitates to compute the quantitative index: ``Non-rhythmic-to-Rhythmic Ratio' index (NRR index). I then used a clinical database to analyze the behavior of NRR index and compare it with other standard indices of anesthetic depth. The positive statistical results suggest that NRR index provides addition clinical information regarding motor reaction, which aligns with current standard tools. Furthermore, the ability to indicates the noxious stimulation is an additional finding. Lastly, I have proposed an real-time interpolation scheme to contribute my study further as a clinical application.