Ibrahim Bassem, Talukder Arghamitra, Jafari Roozbeh
Annu Int Conf IEEE Eng Med Biol Soc. 2020 Jul;2020:3945-3948. doi: 10.1109/EMBC44109.2020.9176495.
Continuous monitoring of cardiac parameters such as blood pressure (BP) and pulse transit time (PTT) from wearable devices can improve the diagnosis and management of the cardiovascular disease. Continuous monitoring of these parameters depends on monitoring arterial pulse wave based on the blood volume changes in the artery using non-invasive sensors such as bio-impedance (Bio-Z). PTT and BP monitoring require the measurement of multiple pulse signals along the artery through the placement of multiple sensors within a small distance. Conventionally, these Bio-Z sensors are excited by a single shared current source, which results in low directivity and distortion of pulse signal due to the interaction of the different sensors together. For a localized pulse sensing, each sensor should focus on a certain point on the artery to provide the most accurate arterial pulse wave, which improves PTT and BP readings. In this paper, we propose a multi-source multi-frequency method for multi-sensor Bio-Z measurement that relies on using separate current sources for each sensor with different frequencies to allow the separation of these signals in the frequency domain, which results in isolation in the spatial domain. The effectiveness of the new method was demonstrated by a reduction in the inter-beat-interval (IBI) root mean square error (RMSE) by 19% and an increase of average PTT by 15% compared to the conventional method.
通过可穿戴设备持续监测诸如血压（BP）和脉搏传输时间（PTT）等心脏参数，可改善心血管疾病的诊断和管理。对这些参数的持续监测依赖于使用生物阻抗（Bio-Z）等非侵入性传感器，基于动脉中血容量变化来监测动脉脉搏波。PTT和BP监测需要通过在小范围内放置多个传感器来测量沿动脉的多个脉冲信号。传统上，这些Bio-Z传感器由单个共享电流源激励，由于不同传感器之间的相互作用，导致脉冲信号的指向性低且失真。对于局部脉搏传感，每个传感器应聚焦于动脉上的某一点，以提供最准确的动脉脉搏波，从而改善PTT和BP读数。在本文中，我们提出了一种用于多传感器Bio-Z测量的多源多频方法，该方法依赖于为每个传感器使用不同频率的单独电流源，以便在频域中分离这些信号，从而在空间域中实现隔离。与传统方法相比，新方法的有效性体现在心跳间隔（IBI）均方根误差（RMSE）降低了19%，平均PTT增加了15%。
