Non-invasive measurements of central blood pressures by RF sensors

项目总结/摘要 动脉血压（BP）和肺动脉压（PAP）是诊断和治疗的基础。 管理全身性和肺动脉高压，并监测手术和危重病 患者全身性高血压是心血管疾病最常见的可改变的危险因素， 是世界上死亡率和残疾率最高的国家。肺动脉高压是一组 导致PAP升高、右心室衰竭和死亡的血管疾病。这也是常见的 加护病房肺动脉高压的诊断仍然具有挑战性。 动脉血压最常用的监测与非侵入性袖带血压计，它只 输出肱动脉收缩压和舒张压，与临界中心血压不同，并且在测量中容易出错。 存在心律失常。代替提供连续测量，其BP值在多个 脉搏有创导管插入术允许直接动脉血压监测，但该技术并非无风险。 通过超声心动图、计算机断层扫描（CT）和磁共振成像（MRI） 磁共振成像（MRI）虽然有用，但仍然是可变的并且依赖于操作者。因此，右心 导管插入术仍然是PAP和肺动脉高压的金标准诊断，尽管高度 侵入性的目前在家庭或初级保健中监测PAP是不可行的。 该提案的首要目标是评估非侵入性射频（RF）传感器是否可以 准确且无创地检索中心BP和PAP瞬变。我们假设近场 通过射频载波进行相干感知（NCS），以心跳和呼吸为基准 波形的黄金标准设备，也可以应用于从振动中获得中央BP 主动脉和肺动脉在整个心动周期中的特征。操作原理 类似于探地雷达和吹气眼压计，其中希尔伯特-黄变换和 机器学习可以适用于BP信号处理。 我们的努力将从建立一个幻影心脏模型开始，这将允许直接泵控制和主机 NCS和导管压力传感器。我们还将探讨多输入多输出（MIMO）网络控制系统 以改善振动特性的局部映射。我们将使用麻醉猪作为动物模型， 主动脉BP和PAP研究，其中将部署来自体模的类似传感器。的准确性 将对传感器及其跟踪黄金标准压力导管变化的能力进行基准测试。 主动脉BP研究将通过输注正性肌力药物和血管加压药进行修改，而PAP则通过急性改变 吸入氧分数（FiO 2）和诱导表面活性物质耗竭，然后肺复张。此外，本发明还 将在动物上同步心电图（ECG）和光电体积描记术（PPG），以研究 是否可以实现NCS BP读数的无创校准。

Project Summary/Abstract Arterial blood pressure (BP) and pulmonary arterial pressure (PAP) are fundamental for diagnosis and management of both systemic and pulmonary hypertension and for monitoring of surgical and critically ill patients. Systemic hypertension is the most common modifiable risk factor for cardiovascular disease and the leading contributor to mortality and disability in the world. Pulmonary hypertension is a group of pulmonary vascular disorders leading to increased PAP, right ventricular failure, and death. It is also common in the intensive care unit. Diagnosis of pulmonary hypertension remains challenging. Arterial BP is most commonly monitored with the non-invasive cuff-based sphygmomanometer, which only outputs brachial systolic and diastolic BP, differs from the critical central BP, and is prone to errors in the presence of arrhythmias. Instead of providing a continuous measurement, its BP values are averaged over many pulses. Invasive catheterization allows for direct arterial BP monitoring, but the technique is not risk-free. Noninvasive estimates of PAP from echocardiography, computed tomography (CT) scan and magnetic resonance imaging (MRI), although useful, remain variable and operator-dependent. Therefore, right heart catheterization is still the gold-standard diagnosis for PAP and pulmonary hypertension, despite being highly invasive. Monitoring of PAP at home or primary care is currently unfeasible. The overarching aim of this proposal is to evaluate whether a non-invasive radio-frequency (RF) sensor can retrieve central BP and PAP transients accurately and non-invasively. We hypothesize that the near-field coherent sensing (NCS) by RF carriers, which has been benchmarked on heartbeat and respiration waveforms with the gold-standard devices, can also be applied to derive central BP from the vibration characteristics of the aorta and pulmonary arteries in the entire cardiac cycle. The principle of operation is similar to that of the ground penetrating radar and air-puff tonometry, where Hilbert-Huang Transforms and machine learning can be adapted for BP signal processing. Our effort will start from building a phantom heart model, which will allow direct pumping control and host the NCS and catheter-based pressure sensors. We will also explore the multiple-input-multiple-output (MIMO) NCS to improve the local mapping of vibration characteristics. We will use anesthetized pigs as animal models for aortic BP and PAP studies, where similar sensors from the phantom will be deployed. The accuracy of the sensors and their ability to track changes in relation to the gold-standard pressure catheters will be benchmarked. Aortic BP studies will be modified by infusion of inotropes and vasopressors, while PAP by acutely changing the fraction of inspired oxygen (FiO2) and by inducing surfactant depletion followed by lung recruitment. Additionally, electrocardiogram (ECG) and photo-plethysmography (PPG) will be synchronized on the animals to investigate whether noninvasive calibration of the NCS BP readout can be realized.