Bottrich Marcel, Laqua Daniel, Husar Peter
Annu Int Conf IEEE Eng Med Biol Soc. 2020 Jul;2020:1-4. doi: 10.1109/EMBC44109.2020.9176692.
A sufficient oxygen supply of the fetus is necessary for a proper development of the organs. Transabdominal fetal pulse oximetry is a method that allows to measure the oxygenation of the fetal blood non-invasively by placing the light sources and photodetectors on the belly of the pregnant woman. The shape of the measured fetal pulse wave is needed to extract parameters for the estimation of the oxygen saturation. This work presents an extension of our previously presented signal processing strategy that allows to extract an average shape of the fetal pulse wave from noisy mixed photoplethysmograms (PPG) with dominating maternal and very weak fetal signal components. An adaptive noise canceller and a comb filter are used to suppress the maternal component. The quality of the resulting fetal signal is sufficient to identify single pulse waves in time domain. Further processing demonstrates the extraction of the mean shape of a single fetal pulse wave by synchronous averaging of several detected pulses. The method is evaluated with different datasets of several simulated and synthetic signals measured with a tissue mimicking phantom. The feasibility of the approach is demonstrated by preparing the mixed PPGs to perform fetal pulse oximetry in future studies. However, clinical measurements are needed to finally evaluate the proposed system beyond synthetic datasets.
为使胎儿器官正常发育，充足的氧气供应必不可少。经腹胎儿脉搏血氧饱和度测定法是一种通过将光源和光电探测器置于孕妇腹部来无创测量胎儿血液氧合情况的方法。为估算氧饱和度而提取参数时，需要测量的胎儿脉搏波形状。本文介绍了我们之前提出的信号处理策略的扩展，该策略能够从噪声混合光电容积脉搏波图（PPG）中提取胎儿脉搏波的平均形状，其中母体信号占主导且胎儿信号非常微弱。使用自适应噪声消除器和梳状滤波器来抑制母体成分。所得胎儿信号的质量足以在时域中识别单个脉搏波。进一步的处理表明，通过对多个检测到的脉搏进行同步平均，可以提取单个胎儿脉搏波的平均形状。该方法通过使用组织模拟体模测量的多个模拟和合成信号的不同数据集进行评估。通过准备混合PPG以在未来研究中进行胎儿脉搏血氧饱和度测定，证明了该方法的可行性。然而，最终评估所提出的系统，除了合成数据集之外还需要进行临床测量。
