可攜式胎兒心電圖監視器之研究

The Development and Implementation of A Portable Fetal Electrocardiogram Monitoring System

徐良育(Liaug-Yu Shyu)

《中原學報》 26卷3期 (1998/08) Pp. 63-69

https://doi.org/10.6358/JCYU.199808.0063

摘要

可攜式胎兒監視系統可幫助高危險群孕婦即早監視胎兒之不正常發展。一般而言，使用非侵入式的胎兒心電圖監視器是最合適且最方便的技術。可是，由母體腹部電極所取得的訊號仍受母親之心電圖、肌電圖及電源所干擾，而造成訊號處理上的困擾。本研究提出利用”胸腹轉換函數”的新式訊號處理方法，改進胎兒心電圖擷取上的缺失。在此基礎上，發展出以數位訊號處理器為架構的即時訊號處理系統，並在處理出胎兒心電圖後，計算胎兒心率，即時輸出至液晶顯示器及記錄於儲存器中。
在長時程的胎兒心率記錄方面，以三組無胎兒訊號之胸部及腹部訊號加上模擬胎兒訊號做測試。模擬胎兒訊號振幅大小設定為母體腹部訊號振幅之 l / 4、l / 5、1 / 7、1 / 10，計算後得到胎兒心搏的正確偵測率由79.79％至99.68 %，與模擬胎兒訊號大小具正相關。在臨床實驗方面，以十組台北榮總婦產科所記錄的待產孕婦之胸部及腹部訊號作為測試訊號。經與個人電腦的離線分析相比較，證實系統可正確的即時處理出胎兒心電圖。實驗結果證實本系統作為長時程胎兒心率記錄器的可行性。

關鍵字

胎兒心電圖訊號處理 ； 胸腹轉移函式 ； 數位訊號處理器

並列摘要

A portable non-invasive fetal electrocardio-gram (FECG) monitoring system is very helpful for high-risk pregnant women to monitor the grow of fetus. However, signals obtained from maternal abdomen are contaminated by maternal ECG (MECG), electromyogram (EMG), and interference from electric device. Correlation analysis is commonly used to extract the FECG. However, the morphology and amplitude of ECGs are moderated by respiration and motion. Thus, large low-frequency noises remain in the processed signal.
A new signal processing method, specifically the thorax-abdomen transfer function, was developed in this laboratory to overcome these drawbacks. By incorporating this method with a digital signal processing chip, a portable real-time FECG monitoring system is developed. The system can not only process the FECG in real time but also store the fetal heart rates for further analysis.
Ten pregnant women were recruited from VGH Taipei to evaluate this system. The FECGs that were obtained by this system are comparable with those processed by off-line method. On the other hand, three sets of thoracic and abdominal ECGs in combination with four simulated FECGs, the am-plitudes are 1/4, 1/5, 1/7, and 1/10 of maternal QRS, are used to evaluate the accuracy and efficiency of this system. The result indicated that the detection rate is in the range of 79.79% to 99.68%. In addi-tion, it clearly demonstrated that the detection rate is highly correlated with the amplitude of FECG. This system is proven to be convenient and accu-rate for long-term fetal monitoring..

並列關鍵字

fetal ECG ； thoracic-abdominal transfer function ； signal processing