利用光容積描記法改善體阻抗心臟容積描繪法的心搏量測量

Using Photoplethysmography to Improve Stroke Volume Measurement of Impedance Cardiography

朱正裕(ZHENG-YU ZHU)

指導教授 ： 劉省宏

朝陽科技大學/資訊學院/資訊工程系/碩士(2019年)

摘要

心搏量是一個很重要的心臟血流力學參數，可以用於評估心臟的泵血功能是否為正常，目前非侵入式的心搏量測量可以使用體阻抗心臟容積描繪方法，透過偵測心臟搏動時所產生的胸腔容抗變化量，進而評估出心搏量。而左心室射血時間是體阻抗心臟容積描繪量測技術中一個重要的參數，但由於體阻抗心臟容積描繪訊號容易受到人為雜訊干擾，導致所測量的左心室射血時間的誤差量變大，進而讓心搏量的誤差量也跟著變大。為解決這個問題，本論文將會使用訊號品質指標來分類光容積描繪法測量到的脈波品質，使用具有高品質的脈波，求得左心室射血時間，進而測量出心搏量。研究中也探討不同的描繪技術所測量的左心室射血時間準確度，使用心音信號測量的左心室射血時間作為標準值，計算體阻抗心臟容積描繪法、頸部光容積描繪法感測器和手指光容積描繪法測量的左心室射血時間的相關係數(r^2)分別為0.041、0.151和1.54×〖10〗^(-3)，以及左心室射血時間差值的平均值和標準差分別為-68.1±148.6、4.7±86.4和-7±107.5毫秒。結果證明了以光容積描繪感測器放置在靠近心臟處，所測量的左心室射血時間，較採用體阻抗心臟容積描繪方法，會更穩定和準確的左心室射血時間。

關鍵字

心搏量 ； 體阻抗心臟容積描繪法 ； 光容積描繪法 ； 訊號品質指標

並列摘要

The stroke volume is a very important parameter in the cardiac hemodynamic measurement that can be used to assess the pumping function of heart. Currently, the non-invasive stroke volume measurement can be performed by the impedance cardio plethysmography (ICG). The ICG method is to detect the amount of impedance changes in the volume of thoracic cavity generated by the heart pumping, and to estimate the stroke volume. Left ventricular ejection time (LVET) is an important parameter in the ICG technology. Because the ICG signal is easily affected by some artifact noise, the accuracy of LVET and stroke volume would be low. In order to solve this problem, this thesis used the signal quality index (SQI) to classify the pulse wave quality measured by the photoplethysmography (PPG) method, and used the high-quality pulse wave to determine the LVET, and then the stroke volume. This research also assessed the accuracy of LVET measured by different PPG techniques. The LVET measured by the Phonocardiography (PCG) signal is used as a standard value, and the correlation coefficient (r^2) of the LVET between the PCG and one of the ICG, neck PPG and finger PPG were 0.041, 0.151, and 1.54×10-3, respectively. The mean and standard deviation of the LVET differences were -68.1 ± 148.6 ms, 4.7 ± 86.4 ms, and -7 ± 107.5 ms. The results showed that the LVET was more stable and accurate than the ICG method when the PPG sensor was placed of a position close to the heart.

並列關鍵字

Stroke volume ； Impedance cardio plethysmography ； photoplethysmography ； Signal quality index

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