Non-Invasive Monitoring of Peripheral Artery Behavior via Wearable Sensors

该项目的目标是使用非侵入性可穿戴传感器监测人体动脉的血管张力和外周血管阻力。血管张力是指动脉的相对扩张或收缩，而外周血管阻力是指心脏在试图通过身体核心外部的动脉系统泵送血液时所感受到的阻力。目前，在医院或其他重症监护环境之外，还没有有效的方法来监测这些影响。尽管如此，已知血管张力和外周血管阻力的变化是各种形式的休克、透析期间危险的血压变化和手术后并发症以及其他可能危及生命的医学状况的进展的关键指标。这项研究将提供一种快速检测外周动脉状况变化的方法，以便更及时地进行干预，更准确地评估治疗效果。该项目还包括在中等教育一级就电子电路和流体行为等主题开展外联活动，这项研究将包括创建一个动态模型，捕捉传感器、组织和局部动脉流体动力学对外部佩戴的顺应性压电压力传感器和相关脉搏体积描记器的响应的最重要贡献。先进的参数识别技术和粘弹性滞后反演方法将用于估计底层动脉的属性，并将传感器响应的趋势与动脉直径的变化相关联。最终目标将是跟踪相对外周动脉半径的变化，而不依赖于可穿戴传感器校准侵入性心血管测量。将通过比较猪实验中的无创与有创血管阻力估计值，并将来自创建的传感器的外周血压和动脉半径估计值与来自较大临床系统（如血压指套和超声）的测量值进行比较来验证结果。这项工作的智力意义预计将包括深入了解关键模型功能描述动态动脉行为在远外围的动脉系统，新技术用于识别参数的非线性，多项式为基础的模型，和信息的变异性外周血管反应在个人经历心血管压力。

The goal of this project is to monitor vascular tone and peripheral vascular resistance of human arteries using non-invasive, wearable sensors. Vascular tone refers to the relative dilation or constriction of arteries, while peripheral vascular resistance refers to the resistance felt by the heart as it attempts to pump blood through the arterial system outside the body's core. At present, there are no effective means of monitoring these effects outside of the hospital or other critical care settings. Nonetheless, changes in vascular tone and peripheral vascular resistance are known to be key indicators of the progression of various forms of shock, dangerous blood pressure changes during dialysis, and post-surgical complications, among other potentially life-critical medical conditions. This research will provide a means to quickly detect changes in the condition of the peripheral arteries, allowing for more timely intervention and more accurate assessment of treatment effectiveness. The project also includes outreach at the secondary education level on topics such as electronic circuits and fluid behavior.This research will include the creation of a dynamic model capturing the most significant contributions of sensor, tissue, and local arterial fluid dynamics to the response of an externally worn compliant piezoelectric pressure sensor and associated pulse plethysmograph. Advanced parameter identification techniques and viscoelastic hysteresis inversion methods will be used to estimate properties of the underlying artery, and correlate trends in sensor response with changes in arterial diameter. The final objective will be to track changes in relative peripheral artery radius without reliance on wearable sensor calibration to invasive cardiovascular measurements. Results will be validated by comparing non-invasive to invasive vascular resistance estimates in experiments with swine, and comparing peripheral blood pressure and arterial radius estimates from the created sensors to measurements from larger clinical systems such as blood pressure finger cuffs and ultrasound. The intellectual significance of the work is expected to include insight into key model features describing dynamic arterial behavior at the far periphery of the arterial system, novel techniques for identifying parameters in nonlinear, polynomial based models, and information on variability in peripheral vascular response across individuals undergoing cardiovascular stresses.