A Smartphone-Based Device for Cuff-Less and Calibration-Free Blood Pressure Monitoring

项目总结/摘要 高血压（BP）是一个主要的心血管危险因素，是可以治疗的，但高血压 认识和控制率很低。无处不在的BP监测技术可以改善 高血压管理，但现有的设备需要可充气的袖带， 随时随地测量血压该项目的总体目标是扩展 适用于大多数自动袖带设备的无袖带和免校准监测原理 英国石油公司通过智能手机。其理念是让用户充当致动器（而不是袖带）， 把她的指尖压在手机上，稳步增加底层的外部压力。 动脉，而手机作为传感器（而不是袖带）通过测量施加的压力 以及由此产生的可变振幅的血容量振荡。手机还提供视觉反馈 并应用算法从测量值计算BP，就像 袖口。基于智能手机的血压监测装置，通过该血压计指压法 将建立。具体目标是：（1）研制一种先进的传感器单元， 测量手指血容量和施加的手指压力;（2）开发先进的算法 根据不同用户群体中的测量结果准确计算BP;以及（3）验证 根据广泛接受的协议的集成设备。将开发一个初始设备， 获得一组全面的潜在有用的测量结果，包括 由眼压计原理产生的手指压力。该设备将由多个- 光电体积描记传感器阵列以识别手指动脉的位置并测量血液 以及用于测量力的面积的多力传感器阵列 应用程序.先进的传感器单元将减轻手指定位不精确的影响。一 将在不同用户人群中使用该器械和袖带器械收集训练数据集。 将对该数据集进行分析，以开发准确计算BP的算法。该算法将 包括利用智能手机摄像头和图像处理来获得BP测量值， 心脏水平和计算手指和肱收缩压，舒张压和平均血压的基础上，各种 测量的生理模型。最终的基于智能手机的设备将被建造， 结合了必要的传感和算法。将根据以下标准对器械进行前瞻性试验： 自动袖带的医疗器械促进协会标准协议 装置.该方案包括85名受试者，包括听诊袖带BP的宽BP范围 作为参考。该项目的成功完成可能最终转化为广泛的BP 监测，从而有助于降低心血管死亡率的发生率。

PROJECT SUMMARY/ABSTRACT High blood pressure (BP) is a major cardiovascular risk factor that is treatable, yet hypertension awareness and control rates are low. Ubiquitous BP monitoring technology could improve hypertension management, but existing devices require an inflatable cuff and thus do not afford anytime, anywhere measurement of BP. The broad goal of this project is to extend the oscillometric principle, which is applied by most automatic cuff devices, for cuff-less and calibration-free monitoring of BP via only a smartphone. The idea is for the user to serve as the actuator (instead of the cuff) by pressing her fingertip against the phone to steadily increase the external pressure of the underlying artery, while the phone serves as the sensor (rather than the cuff) by measuring the applied pressure and resulting variable-amplitude blood volume oscillations. The phone also provides visual feedback to guide the finger actuation and applies an algorithm to compute BP from the measurements just like a cuff. A smartphone-based device for BP monitoring via this oscillometric finger pressing method will be established. The specific aims are: (1) to develop an advanced sensor-unit to robustly measure the finger blood volume and applied finger pressure; (2) to develop an advanced algorithm to accurately compute BP from the measurements in a diverse user population; and (3) to validate the integrated device according to a widely accepted protocol. An initial device will be developed to acquire a comprehensive set of potentially useful measurements including the pulsatile component of the finger pressure arising from the tonometric principle. This device will consist of a multi- photoplethysmography sensor array to identify the location of the finger artery and measure the blood volume oscillations from therein and a multi-force sensor array to measure the area of force application. The advanced sensor-unit will mitigate the impact of imprecise finger positioning. A training dataset will be collected with this device and cuff-based devices in a diverse user population. This dataset will be analyzed to develop an algorithm to accurately compute BP. The algorithm will include leveraging the smartphone camera and image processing to obtain the BP measurement at heart level and computing finger and brachial systolic, diastolic, and mean BP based on various physiologic models of the measurements. A final smartphone-based device will be built that incorporates the requisite sensing and algorithm. The device will be prospectively tested according to the standard Association for the Advancement of Medical Instrumentation protocol for automatic cuff devices. This protocol includes 85 subjects encompassing a wide BP range with auscultation cuff BP as the reference. Successful completion of this project could ultimately translate to widespread BP monitoring and thereby help reduce the incidence of cardiovascular mortality.