拉普拉斯電極為基礎之胎兒心電圖監測系統

Laplace Electrode Based Monitoring System of The Feltal Electrocardiogram

余宗翰(Zong-Han Yu)

指導教授 ： 徐良育

中原大學/工學院/生物醫學工程研究所/碩士(2015年)

https://doi.org/10.6840/cycu201500791

摘要

胎兒心電圖為監護胎兒心臟生理活動的參考指標之一。由於懷孕期間預測胎兒的健康狀況是非常重要，因此需要透過量測胎兒心電訊號來評估胎兒的生長以及發育情形。量測孕婦腹部訊號較為方便且具安全性，但胎兒訊號相對較小且包含較多的雜訊，要擷取到乾淨的胎兒心電訊號前必須先去除不必要的雜訊。
本研究以類拉普拉斯電極擷取胎兒心電訊號，此拉普拉斯電極為導電織布所製成，放置於托腹帶中作為前端電極。拉普拉斯電極所涵蓋的腹部面積較大，因此能夠減少由於胎位以及電極擺放位置所造成的影響。利用德州儀器所出產的TMS320C5515定點數數位處理器透過串列傳輸的方式來控制ADS1294晶片以擷取腹部訊號。ADS1294晶片能夠減少以往多導程胎心電擷取系統的前端線路。再將擷取的訊號透過數位處理器進行演算並獲得胎兒心率，最後透過低功耗藍牙傳輸至智慧型行動裝置顯示，以便觀測胎兒心率變化趨勢。
在演算法部分，本研究利用PhysioNet chllange 2013 set A 資料庫中的訊號進行驗證，選擇二十組訊號進行測試，正確率為75.48%。但原輸入訊號的品質會大大的影響正確率。
本研究也將系統實際應用在孕婦上，結果顯示，本電極系統可以成功採集母親腹部訊號。再者，經由偵測到的胎兒心電圖R波位置與專家標記的胎兒R波位置進行比對，準確率為69.3%。
結論，本研究成功完成拉普拉斯電極胎兒心電監護系統，不但能擷取腹部訊號，並利用演算法成功分離母親以及胎兒心電訊號。

關鍵字

胎兒心電訊號:自適應濾波:拉普拉斯電極

並列摘要

The fetal electrocardiogram (FECG) is one of the reference index for monitoring the fetal heart physiological activity. It is very important to predict the health of fetus during pregnancy. Therefore, it is necessary to evaluate the growth and development of fetal through the measurement of FECG signal. By measuring signals from the abdomen of pregnant women is convenient and secure. However, the fetal signal is relatively small and contains more noise. To capture a clean FECG signal, the unwanted noise must be removed.
This study developed a electrode system that is similar to a enlarged Laplace electrode to acquire FECG signal. The Laplace electrodes made of conductive fabric, and placed on a maternity belt as the front-end electrode to detect abdomen signals. The enlarged Laplace electrode can cover large abdominal area. Thus, it is possible to reduce the impact caused by the position of fetal and electrode placement. The TMS320C5515 fixed-point digital signal processor from the Texas Instrumentation was used to control the ADS1294, using serial peripheral interface (SPI). The ADS1294 can reduce the front end electronic circuit used by multi-lead ECG acquisition system. The acquired signal is fetched into the digital signal processor to perform the signal processing algorithm and determine the fetal heart rate. Finally, results are transmitted through the Bluetooth low energy in order to observe the fetal heart rate trends.
This study uses the PhysioNet challenge 2013 set A database to validate the proposed signal processing algorithm. Twenty signal set was selected for testing, and the accuracy is 75.48%. However, the quality of acquired signal will affect the averaged accuracy significantly.
This study also uses the proposed system on pregnant women. The results indicate that this system can acquire abdomen signals successfully. By comparing the detected FECG R wave positions and the fetal R wave positions marked by experts, the averaged accuracy of fetal QRS detection was 69.3%.
In conclusion, the study constructs a Laplace electrode system for fetal monitoring. The proposed signal processing algorithm can successfully separates the maternal and fetal ECG, detects the fetal QRS, and computes the fetal heart rate.

並列關鍵字

Fetal Electrocardiography:Adaptive Filter:Laplacian Electrode

參考文獻

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