Pulse Volume Sensing and Analysis for Advanced Blood Pressure Monitoring

Pulse Volume Sensing and Analysis for Advanced Blood Pressure Monitoring
Author: Keerthana Natarajan
Publisher:
Total Pages: 87
Release: 2021
Genre: Electronic dissertations
ISBN:

Download Pulse Volume Sensing and Analysis for Advanced Blood Pressure Monitoring Book in PDF, Epub and Kindle

Approximately a quarter of the world's population is affected by high blood pressure (BP). It is a major risk factor for stroke and heart disease, which are leading causes of mortality. Management of hypertension could be improved by increased accuracy and convenience of BP measurement devices. Existing devices are not convenient or portable enough. In this work, we investigate three approaches to improve the accuracy and convenience of BP measurement.A physiologic method was developed to further advance central BP measurement. A patient-specific method was applied to estimate brachial BP levels from a cuff pressure waveform obtained during conventional deflation via a nonlinear arterial compliance model. A physiologically-inspired method was then employed to extract the PVP waveform from the same waveform via ensemble averaging and calibrate it to the brachial BP levels. A method based on a wave reflection model was thereafter employed to define a variable transfer function, which was applied to the calibrated waveform to derive central BP. This method was evaluated against invasive central BP measurements from patients. The method yielded central systolic, diastolic, and pulse pressure bias and precision errors of −0.6 to 2.6 and 6.8 to 9.0mmHg. The conventional oscillometric method produced similar bias errors but precision errors of 8.2 to 12.5mmHg (p≤0.01). The new method can derive central BP more reliably than some current non-invasive devices and in the same way as traditional cuff BP.We then developed an iPhone X application to measure cuff-less BP via the "oscillometric finger pressing method". The user presses her fingertip on both the front camera and screen to increase the external pressure of the underlying artery, while the application measures the resulting variable-amplitude blood volume oscillations via the camera and applied pressure via the strain gauge array under the screen. The application also visually guides the fingertip placement and actuation and then computes BP from the measurements just like many automatic cuff devices. We tested the application, along with a finger cuff device, against a standard cuff device. The application yielded bias and precision errors of −4.0 and 11.4mmHg for systolic BP and −9.4 and 9.7mmHg for diastolic BP (n=18). These errors were near the finger cuff device errors. This proof-of-concept study surprisingly indicates that cuff-less and calibration-free BP monitoring may be feasible with many existing and forthcoming smartphones. Finally, we developed easy-to-understand models relating PPG waveform features to BP changes (after a single cuff calibration) and determined conclusively whether they provide added value or not in BP measurement accuracy. Stepwise linear regression was employed so as to create parsimonious models for predicting the intervention-induced BP changes from popular PPG waveform features, pulse arrival time (PAT, time delay between ECG R-wave and PPG foot), and subject demographics. The finger b-time (PPG foot to minimum second derivative time) and ear STT (PPG amplitude divided by maximum derivative), when combined with PAT, reduced the systolic BP change prediction RMSE of reference models by 6-7% (p

Photoplethysmography

Photoplethysmography
Author: Panicos A. Kyriacou
Publisher: Academic Press
Total Pages: 508
Release: 2021-11-03
Genre: Technology & Engineering
ISBN: 012823525X

Download Photoplethysmography Book in PDF, Epub and Kindle

Photoplethysmography: Technology, Signal Analysis, and Applications is the first comprehensive volume on the theory, principles, and technology (sensors and electronics) of photoplethysmography (PPG). It provides a detailed description of the current state-of-the-art technologies/optical components enabling the extreme miniaturization of such sensors, as well as comprehensive coverage of PPG signal analysis techniques including machine learning and artificial intelligence. The book also outlines the huge range of PPG applications in healthcare, with a strong focus on the contribution of PPG in wearable sensors and PPG for cardiovascular assessment. Presents the underlying principles and technology surrounding PPG Includes applications for healthcare and wellbeing Focuses on PPG in wearable sensors and devices Presents advanced signal analysis techniques Includes cutting-edge research, applications and future directions

The Handbook of Cuffless Blood Pressure Monitoring

The Handbook of Cuffless Blood Pressure Monitoring
Author: Josep Solà
Publisher: Springer Nature
Total Pages: 239
Release: 2019-08-21
Genre: Medical
ISBN: 3030247015

Download The Handbook of Cuffless Blood Pressure Monitoring Book in PDF, Epub and Kindle

This book is the first comprehensive overview of the emerging field of cuffless blood pressure monitoring. Increasing clinical evidence proves that longitudinal measurements of blood pressure allow for earlier detection and better management of multiple medical conditions and for superior prediction of cardiovascular events. Unfortunately, today’s clinical and industry standards for blood pressure monitoring still require the inflation of a pneumatic cuff around a limb each time a measurement is taken. Over the last decades clinicians, scientists and device manufacturers have explored the feasibility of technologies that reduce or even completely eliminate the need of cuffs, initiating the era of cuffless blood pressure monitoring. Among the existing literature, this book is intended to be a practical guide to navigate across this emerging field. The chapters of the handbook have been elaborated by experts and key opinion leaders in the domain, and will guide the reader along the clinical, scientific, technical, and regulatory aspects of cuffless blood pressure monitoring.

Manual, Electronic, Or Automated Sphygmomanometers

Manual, Electronic, Or Automated Sphygmomanometers
Author: Association for the Advancement of Medical Instrumentation
Publisher:
Total Pages: 70
Release: 2003-05
Genre: Sphygmomanometers
ISBN: 9781570201837

Download Manual, Electronic, Or Automated Sphygmomanometers Book in PDF, Epub and Kindle

Basic Sciences for MCEM

Basic Sciences for MCEM
Author: Chetan Trivedy
Publisher: CRC Press
Total Pages: 771
Release: 2016-05-15
Genre: Medical
ISBN: 0340985011

Download Basic Sciences for MCEM Book in PDF, Epub and Kindle

This book is a dedicated resource for those sitting the Part A of the MCEM (Membership of the College of Emergency Medicine) examination. It forms an essential revision guide for emergency trainees who need to acquire a broad understanding of the basic sciences, which underpin their approach to clinical problems in the emergency department. Common clinical scenarios are used to highlight the essential underlying basic science principles, providing a link between clinical management and a knowledge of the underlying anatomical, physiological, pathological and biochemical processes. Multiple choice questions with reasoned answers are used to confirm the candidates understanding and for self testing. Unlike other recent revision books which provide MCQ questions with extended answers, this book uses clinical cases linked to the most recent basic science aspects of the CEM syllabus to provide a book that not only serves as a useful revision resource for the Part A component of the MCEM examination, but also a unique way of understanding the processes underlying common clinical cases seen every day in the emergency department. This book is essential for trainees sitting the Part A of the MCEM exam and for clinicians and medical students who need to refresh their knowledge of basic sciences relevant to the management of clinical emergencies.

Advanced Hemodynamic Monitoring: Basics and New Horizons

Advanced Hemodynamic Monitoring: Basics and New Horizons
Author: Mikhail Y. Kirov
Publisher: Springer Nature
Total Pages: 289
Release: 2021-08-31
Genre: Medical
ISBN: 3030717526

Download Advanced Hemodynamic Monitoring: Basics and New Horizons Book in PDF, Epub and Kindle

This book describes how to monitor and optimize cardiovascular dynamics using advanced hemodynamic monitoring in perioperative and intensive care medicine. The book outlines basic skills of hemodynamic monitoring, different techniques including invasive, minimally invasive, and non-invasive methods, and algorithms and treatment strategies for perioperative goal-directed hemodynamic therapy in different groups of surgical patients. Thus, the book reflects current diagnostic and therapeutic approaches in perioperative and intensive care medicine. All sections of this book have a learning-oriented style and are illustrated with tables and figures summarizing the main content. The volume is addressed both to specialists and residents using advanced hemodynamic monitoring; it reflects indications and limitations of current monitoring tools and discuss therapeutic strategies. It also helps readers to integrate new knowledge on monitoring of cardiovascular dynamics into clinical practice.

Development of a Wearable Blood Pressure Monitor Using Adaptive Calibration of Peripheral Pulse Transit Time Measurements

Development of a Wearable Blood Pressure Monitor Using Adaptive Calibration of Peripheral Pulse Transit Time Measurements
Author: Devin Barnett McCombie
Publisher:
Total Pages: 159
Release: 2008
Genre:
ISBN:

Download Development of a Wearable Blood Pressure Monitor Using Adaptive Calibration of Peripheral Pulse Transit Time Measurements Book in PDF, Epub and Kindle

(Cont.) Additionally, by co-locating the two sensors on the same appendage not only are we able to account for the effect of hydrostatic pressure variation in our pulse transit time (PTT) measurements using an imbedded height sensor, but by actively altering the height of the two sensors relative to the heart we can achieve real-time identification of the calibration equation mapping PTT to MAP. Such real-time calibration of PTT measurements obviates the need for obtrusive cuff-based blood pressure monitors and offers the potential to recursively update the calibration equation as the patient's cardiovascular state evolves throughout the duration of the measurement period. Adaptive PTT calibration through natural patient motion has never previously been explored and offers the potential to achieve the longstanding goal of a truly imperceptible, wearable home BP monitor. This thesis describes the design and development of the sensor hardware used in the wearable device. Based on both theoretical study and experimental observations a device model has been developed to allow estimation of mean arterial blood pressure using the pulse transit times measured with our sensors. Additionally, this thesis presents the adaptive calibration methodology and the novel system identification algorithms that were used to parameterize our device model using natural human motion. Finally, this thesis demonstrates the potential of these innovative concepts through human subject testing and data analysis.

Blood Pressure Monitoring in Cardiovascular Medicine and Therapeutics

Blood Pressure Monitoring in Cardiovascular Medicine and Therapeutics
Author: William B. White
Publisher: Humana Press
Total Pages: 422
Release: 2015-12-20
Genre: Medical
ISBN: 3319227718

Download Blood Pressure Monitoring in Cardiovascular Medicine and Therapeutics Book in PDF, Epub and Kindle

This new edition is devoted to a broad array of topics involving the circadian variation in cardiovascular diseases, with focuses on hypertension, stroke, and coronary disease. The volume covers clinical and device research related to home and ambulatory BP monitoring, as there have been significant advances in technology since the publication of the previous edition. In addition, there is an increased focus on the applicability of home and ambulatory BP monitoring in drug development in all therapeutic arenas. The text features contributions from chapter authors from around the world and who have great expertise in cardiovascular medicine, therapeutics, clinical trials, and evidence-based medicine. Blood Pressure Monitoring in Cardiovascular Medicine and Therapeutics, Third Edition is essential reading for a large audience, including those practicing cardiology and nephrology with a special focus in hypertension, geriatrics and internal medicine, clinical trialists, regulators in the US, Europe, and Japan, and physicians in training in cardiology, hypertension, pharmacology, nephrology and neurology.

Blood Pressure Measurements

Blood Pressure Measurements
Author: W. Meyer-Sabellek
Publisher: Springer Science & Business Media
Total Pages: 547
Release: 2012-12-06
Genre: Medical
ISBN: 364272423X

Download Blood Pressure Measurements Book in PDF, Epub and Kindle

In addition to standardized casual blood pressure readings, ambulatory blood pressure monitoring (ABPM) - using automatic noninvasive (= indirect) devices for home readings and fully automated monitors for 24-h profiles - have become a widely used necessary tool in clinical research. This book summarizes the state of the art in the whole field of indirect blood pressure monitoring. It is based on two international meetings and on invited papers. We have divided the subject matter into two main areas: 1) Automatic blood pressure devices for discontinuous registration, and 2) Portable, fully automated programmable monitors for continuous monitoring. The availability of all new technologies is described in detail and current technical and physiological problems have been covered in depth. Both topics have been subdivided into a) Methods and Techniques, and b) Clinical Applications. Both parts are updated and have critically evaluated available automatic sphygmomanometers and portable computers equipped with different techni ques (e. g. , auscultation, oscillometry, plethysmography). Reliability in the intensiv Care unit as well as in outpatients management, common clinical problems, clinical relevance compared to casual blood pressure are described in the first part. In the second part, ten years of experience on fully automated noninvasive methodology - compared to intraarterial techniques - have been elaborated by international experts; the possibilities and limitations are clearly demonstrated. Analyses in different clinical fields in the diagnosis of primary and secondary hypertension are given. Different statistical analyses of blood pressure variability and circadian rhythms are discussed.

Non-invasively Obtained Central Blood Pressure

Non-invasively Obtained Central Blood Pressure
Author: Hao-min Cheng
Publisher:
Total Pages: 370
Release: 2013
Genre: Blood pressure
ISBN:

Download Non-invasively Obtained Central Blood Pressure Book in PDF, Epub and Kindle

Recently, novel concepts and medical technologies have developed rapidly with enormous growth and unprecedented expansion in the range of interventions and knowledge offered for health professionals in their clinical decision making. This burgeoning innovation has not necessarily resulted in an incremental availability of knowledge to policymakers and clinicians. In this study critical translation gaps have been addressed strategically in the research-into-action cycle to improve outcomes and services. Given widespread acceptance that waveform morphology and blood pressure (BP) differ considerably between the central aorta and peripheral arterial system, it is clear that BP measurements in the peripheral arteries cannot serve as direct substitutes for their central counterparts. Although non-invasive BP measured in the brachial artery (cuff BP) is the basis for the present management of hypertension, central blood pressure (CBP) has been shown to be the better predictor of cardiovascular outcomes than cuff BP. Consequently, there are substantial research efforts to develop non-invasive estimating methods for CBP, mainly based on the technique of applanation tonometry. However, CBP measured has not been widely adopted in clinical practice. One of the possible gaps is that tonometry-based measurement requires some skills and time to perform and it is a relatively expensive technique. Besides, the accuracy of the current tonometry-based techniques has been questioned. To identify and address the gaps of translating the evidence of the importance of CBP, a series of studies were conducted. To identify existing gaps, I carried out a systematic review and meta-analysis of studies comparing tonometry-based CBP estimates with invasively measured central BP and found that present tonometry-based CBP estimating methods are acceptable in theory, with small errors. However, there is substantial room for improvement in measurement accuracy of CBP. To develop a more accurate, less expensive, and less technically dependent CBP measurement technique, the pulse wave analysis (PWA) technique for brachial pulse volume plethysmography (PVP) waveforms from an oscillometric blood pressure monitor was implemented. Evaluation demonstrated that large random and systematic errors are introduced into the central pulse pressure (PP) estimates when they are calculated as the difference between the estimated central systolic BP (SBP) and central or cuff diastolic BP (DBP), which can be improved substantially with the novel PWA approach. Subsequently, the novel technique was seamlessly incorporated into a standalone automatic BP monitor. In a rigorous validation study, it was demonstrated that CBP can be measured accurately by this stand-alone automatic blood pressure monitor. To apply the CBP concept in clinical practice, the gap between innovation and clinical application should be closed. The diagnostic threshold for confirming a diagnosis of hypertension with CBP has never been proposed; I therefore derived and validated the diagnostic threshold of CBP based on two independent event-based cohorts with long-term follow-up. With the proposed cut-off limits for the diagnosis of hypertension, the diagnostic accuracy of the stand-alone CBP monitor reference to invasively measured CBP was estimated. It was then suggested that traditional cuff BP may be reliable in confirming the diagnosis of hypertension and in justifying subsequent treatment with its high specificity. However, because of low sensitivity, the cuff BP could render possible management inaccessible to a considerable proportion of hypertensive subjects, who may be identifiable through the noninvasive CBP monitor. Finally, in responding to the gap between clinical application and policy, a health economic evaluation was required to support the cost-effectiveness of the new emerging technique. A comprehensive Markov modelling was performed and this confirmed the cost-effectiveness of CBP monitoring, which resulted from a greater quality gain that outweighed its supplementary cost. Given more data supporting the diagnostic and prognostic role of CBP, it should be considered to be an effective strategy for the management of hypertension.