The 2023 wearable photoplethysmography roadmap

Photoplethysmography is a key sensing technology which is used in wearable devices such as smartwatches and fitness trackers. Currently, photoplethysmography sensors are used to monitor physiological parameters including heart rate and heart rhythm, and to track activities like sleep and exercise. Yet, wearable photoplethysmography has potential to provide much more information on health and wellbeing, which could inform clinical decision making. This Roadmap outlines directions for research and development to realise the full potential of wearable photoplethysmography. Experts discuss key topics within the areas of sensor design, signal processing, clinical applications, and research directions. Their perspectives provide valuable guidance to researchers developing wearable photoplethysmography technology

Robust Algorithms for Unattended Monitoring of Cardiovascular Health

Cardiovascular disease is the leading cause of death in the United States. Tracking daily changes in one’s cardiovascular health can be critical in diagnosing and managing cardiovascular disease, such as heart failure and hypertension. A toilet seat is the ideal device for monitoring parameters relating to a subject’s cardiac health in his or her home, because it is used consistently and requires no change in daily habit. The present work demonstrates the ability to accurately capture clinically relevant ECG metrics, pulse transit time based blood pressures, and other parameters across subjects and physiological states using a toilet seat-based cardiovascular monitoring system, enabled through advanced signal processing algorithms and techniques. The algorithms described herein have been designed for use with noisy physiologic signals measured at non-standard locations. A key component of these algorithms is the classification of signal quality, which allows automatic rejection of noisy segments before feature delineation and interval extractions. The present delineation algorithms have been designed to work on poor quality signals while maintaining the highest possible temporal resolution. When validated on standard databases, the custom QRS delineation algorithm has best-in-class sensitivity and precision, while the photoplethysmogram delineation algorithm has best-in-class temporal resolution. Human subject testing on normative and heart failure subjects is used to evaluate the efficacy of the proposed monitoring system and algorithms. Results show that the accuracy of the measured heart rate and blood pressure are well within the limits of AAMI standards. For the first time, a single device is capable of monitoring long-term trends in these parameters while facilitating daily measurements that are taken at rest, prior to the consumption of food and stimulants, and at consistent times each day. This system has the potential to revolutionize in-home cardiovascular monitoring

Detecting Vital Signs with Wearable Wireless Sensors

The emergence of wireless technologies and advancements in on-body sensor design can enable change in the conventional health-care system, replacing it with wearable health-care systems, centred on the individual. Wearable monitoring systems can provide continuous physiological data, as well as better information regarding the general health of individuals. Thus, such vital-sign monitoring systems will reduce health-care costs by disease prevention and enhance the quality of life with disease management. In this paper, recent progress in non-invasive monitoring technologies for chronic disease management is reviewed. In particular, devices and techniques for monitoring blood pressure, blood glucose levels, cardiac activity and respiratory activity are discussed; in addition, on-body propagation issues for multiple sensors are presented

A health-shirt using e-textile materials for the continuous monitoring of arterial blood pressure.

Chan, Chun Hung.Thesis (M.Phil.)--Chinese University of Hong Kong, 2008.Includes bibliographical references (leaves 77-84).Abstracts in Chinese and English.Acknowledgment: --- p.i摘要 --- p.iiAbstract --- p.ivList of Figure --- p.viList of Table --- p.viiiContent Page --- p.ixChapter Chapter 1 --- Introduction --- p.1Chapter 1.1 --- The Difficulties --- p.1Chapter 1.2 --- The Solution --- p.2Chapter 1.3 --- Goal of the Present Work --- p.2Chapter Chapter 2 --- Background and Methodology --- p.3Chapter 2.1 --- Hypertension Situation and Problems Around the World --- p.3Chapter 2.1.1 --- Blood Pressure Variability (BPV) --- p.4Chapter 2.2 --- Blood Pressure Measuring Methods --- p.5Chapter 2.2.1 --- Traditional Blood Pressure Meters --- p.6Chapter 2.2.2 --- Limitation of Commercial Blood Pressure Meters --- p.7Chapter 2.2.3 --- Pulse-Transit-Time (PTT) Based Blood Pressure Measuring Watch --- p.7Chapter 2.3 --- Wearable Body Sensors Network / System --- p.8Chapter 2.4 --- Current Status of e-Textile Garment --- p.9Chapter 2.4.1 --- Blood Pressure Measurement in e-Textile Garment --- p.13Chapter 2.5 --- Wearable Intelligent Sensors and System for e-Health (WISSH) --- p.15Chapter 2.5.1 --- "Monitoring, Connection and Display" --- p.15Chapter 2.5.2 --- Treatment --- p.16Chapter 2.5.3 --- Alarming --- p.17Chapter Chapter 3 --- "A h-Shirt to Non-invasive, Continuous Monitoring of Arterial Blood Pressure" --- p.18Chapter 3.1 --- Design and Inner Structure of h-Shirt --- p.18Chapter 3.1.1 --- Choose of e-Textile Material --- p.21Chapter 3.1.2 --- Design of ECG Circuit --- p.23Chapter 3.1.3 --- Design of PPG Circuit --- p.26Chapter 3.2 --- Blood Pressure Estimation Using Pulse-Transit-Time Algorithm --- p.28Chapter 3.2.1 --- Principal --- p.28Chapter 3.2.2 --- Equations --- p.29Chapter 3.2.3 --- Calibration --- p.29Chapter 3.3 --- Performance Tests on h-Shirt --- p.30Chapter 3.3.1 --- Test I: BP Measurement Accuracy --- p.30Chapter 3.3.2 --- Test I: Procedure and Protocol --- p.30Chapter 3.3.3 --- Test I-Results --- p.31Chapter 3.3.4 --- Test II: Continuality BP Estimation Performance --- p.31Chapter 3.3.5 --- Test II - Experiment Procedure and Protocol --- p.32Chapter 3.3.6 --- Test II - Experiment Result --- p.33Chapter 3.3.7 --- Test II 一 Discussion --- p.43Chapter 3.4 --- Follow-up Tests on ECG Circuit --- p.47Chapter 3.4.1 --- Problems --- p.47Chapter 3.4.2 --- Assumptions --- p.48Chapter 3.4.3 --- Experiment Protocol and Setup --- p.48Chapter 3.4.4 --- Experiment Results --- p.53Chapter 3.4.5 --- Discussion --- p.56Chapter Chapter 4: --- Hybrid Body Sensor Network in h-Shirt --- p.59Chapter 4.1 --- A Hybrid Body Sensor Network --- p.59Chapter 4.2 --- Biological Channel Used in h-Shirt --- p.60Chapter 4.3 --- Tests of Bio-channel Performance --- p.62Chapter 4.3.1 --- Experiment Protocol --- p.62Chapter 4.3.2 --- Results --- p.62Chapter 4.4 --- Discussion and Conclusion --- p.63Chapter Chapter 5: --- Conclusion and Suggestions for Future Works --- p.66Chapter 5.1 --- Conclusion --- p.66Chapter 5.1.1 --- Structure of h-Shirt --- p.66Chapter 5.1.2 --- Blood Pressure Estimating Ability of h-Shirt --- p.67Chapter 5.1.3 --- Tests and Amendments on h-Shirt ECG Circuit --- p.67Chapter 5.1.4 --- Hybrid Body Sensor Network in h-Shirt --- p.67Chapter 5.2 --- Suggestions for Future Work --- p.68Chapter 5.2.1 --- Further Development of Bio-channel Biological Model --- p.68Chapter 5.2.2 --- Positioning and Motion Sensing with h-Shirt --- p.69Chapter 5.2.3 --- Implementation of Updated Advance Technology into h-Shirt --- p.69Appendix: Non-invasive BP Measuring Device - Finometer --- p.71Reference: --- p.7

A wearable blood pressure sensor using oscillometric photoplethysmography and micro accelerometers

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.Includes bibliographical references (leaves 119-124).Monitoring arterial blood pressure (ABP) with a sensor virtually imperceptible to the wearer, for continuous periods of weeks, months, or years, could prove revolutionary in the diagnosis and treatment of chronic hypertension and heart failure, as well as a monitoring tool for convalescing individuals, and individuals in hazardous duty (such as firefighters or soldiers). To this end, a miniaturizable, non-invasive blood pressure sensor is designed and validated. A solid, coin-sized cuff-less photoplethysmography (PPG) sensor worn over a palpable artery is utilized to measure arterial blood pressure. Measurements are obtained through a modified oscillometric technique which eliminates the need for a high pressure cuff and instead, takes advantage of natural hydrostatic pressure changes caused by raising and lowering the subject's arm. In this work, the principle of hydrostatic oscillometry is first detailed. To better understand the internal mechanisms of pressure propagation within the tissue, a comprehensive non-linear finite element model of the finger base is constructed and validated using a combination of magnetic resonance imaging and experimental tissue stiffness measurements.(cont.) A prototype finger blood pressure monitor is designed and constructed in combination with a novel accelerometer-based height sensor. The 95% confidence interval for a Bland-Altman comparison between the proposed sensor's mean arterial pressure (MAP) measurements and the simultaneous Finapres MAP measurements is [+919, -283] Pa ([+6.91, -9.04] mmHg). The percent difference between the two methods is shown to be 3.0%. A method for continuous MAP measurements utilizing the sensor system is proposed and is shown to be capable of providing reliable measurements for several minutes.by Phillip Andrew Shaltis.Ph.D

New methods for continuous non-invasive blood pressure measurement

Hlavním cílem této práce je nalezení nové metodiky pro měření kontinuálního neinvazivního krevního tlaku na základě rychlosti šíření pulzní vlny v krevním řečišti. Práce se opírá o rešerši zabývající se základním modelem pro stanovení kontinuálního neinvazivního krevního tlaku na základě měření zpoždění pulzní vlny a jeho rozšířením. Z informací získaných z rešerše se upravila metodika měření doby zpoždění pulzní vlny / rychlosti šíření pulzní vlny, aby bylo možné docílit přesnějších výsledků a omezit tak lidský faktor, který způsobuje významnou nepřesnost vlivem nedokonalého rozmístění senzorů. Rešerše se rovněž podrobně zabývá modely pro stanovení kontinuálního neinvazivního krevního tlaku a jejich úprav zajištujících zvýšení přesnosti. Mezi úpravy modelů zejména patří vstupní parametry popisující krevní oběh - systémový cévní odpor, elasticita cév, tuhost cév. Práce se taky zabývá úpravami stávajícího modelu krevního řečiště pro bližší přizpůsobení fyzického modelu k reálnému cévnímu systému lidského těla. Mezi tyto úpravy patří i funkce baroreflexu či simulace různé tvrdosti stěny umělých cévních segmentů. Protože se jedná o simulační model krevního řečiště, důležitým krokem je také měření tlakové a objemové pulzní vlny, kde není možné využít konvenční senzory pro fotopletysmografii kvůli absenci částic pohlcující světlo. Na základě experimentálního měření pro různé nastavení modelu krevního řečiště bylo provedeno měření pulzní vlny pomocí tlakových a kapacitních senzorů s následným zpracováním měřených signálů a detekcí příznaků charakterizující pulzní vlnu. Na základě příznaku byly stanoveny predikční regresní modely, které vykazovaly dostatečnou přesnost jejich určení, a tak následovaly dvě metody pro získání parametru o tvrdosti cévní stěny na základě měřitelných parametrů. První metodou byl predikční regresní model, který vykazoval přesnost 74,1 % a druhou metodou byl adaptivní neuro-fuzzy inferenční systém, který vykazoval přesnost 98,7 %. Tyto stanovení rychlosti pulzní vlny bylo ověřeno dalším přímým měřením pulzní vlny a výsledky byly srovnány. Výsledkem disertační práce je určení rychlosti šíření pulzní vlny s využitím pouze jednoho pletysmografického senzoru bez nutnosti měření na dvou různých místech s přesným měřením vzdálenosti a možnosti aplikace v klinické praxi.The main objective of this work is to find a new methodology for measuring continuous non-invasive blood pressure based on the pulse wave velocity in the vascular system. The work is based on the literature research of the basic model for the determination of non-invasive continuous blood pressure based on the measurement of pulse transit time. From the information obtained from the review, the methodology of measuring the pulse transit time/pulse wave velocity was modified in order to achieve more accurate results and to reduce the human factor that causes significant inaccuracy due to imperfect sensor placement. The review discusses in detail the models for continuous non-invasive blood pressure estimation and their modifications to ensure increased accuracy. In particular, model modifications include input parameters describing blood circulation - systemic vascular resistance, vascular elasticity, and vascular stiffness. The thesis deals with modifications to the existing physical vascular model to more closely mimic the real vascular system of the human body. These modifications include the baroreflex function or the simulation of different wall hardness of artificial arterial segments. As this is a simulation model of the vascular system, the measurement of pressure and volume pulse wave is also an important step, where it is not possible to use photoplethysmography method due to the absence of light absorbing particles. Based on the experimental measurements for different settings of the vascular model, pulse wave measurements were performed using pressure and capacitive sensors with subsequent processing of the measured signals and detection of the pulse wave features. Predictive regression models were established based on the pulse wave features and showed sufficient accuracy in their determination, followed by two methods for obtaining the parameter on the hardness of the vascular wall based on the measurable parameters. The first method was a predictive regression model, which showed an accuracy of 74.1 %, and the second method was an adaptive neuro-fuzzy inference system, which showed an accuracy of 98.7 %. These pulse wave velocity determinations were verified by further direct pulse wave measurements and the results were compared. The dissertation results in the determination of pulse wave propagation velocity using only one plethysmographic sensor without the need for measurements at two different locations with accurate distance measurements and the possibility of application in clinical practice.450 - Katedra kybernetiky a biomedicínského inženýrstvívyhově