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Davies HJ, Hammour G, Xiao H, Bachtiger P, Larionov A, Molyneaux PL, Peters NS, Mandic DP. Physically Meaningful Surrogate Data for COPD. IEEE OPEN JOURNAL OF ENGINEERING IN MEDICINE AND BIOLOGY 2024; 5:148-156. [PMID: 38487098 PMCID: PMC10939325 DOI: 10.1109/ojemb.2024.3360688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 11/23/2023] [Accepted: 01/26/2024] [Indexed: 03/17/2024] Open
Abstract
The rapidly increasing prevalence of debilitating breathing disorders, such as chronic obstructive pulmonary disease (COPD), calls for a meaningful integration of artificial intelligence (AI) into respiratory healthcare. Deep learning techniques are "data hungry" whilst patient-based data is invariably expensive and time consuming to record. To this end, we introduce a novel COPD-simulator, a physical apparatus with an easy to replicate design which enables rapid and effective generation of a wide range of COPD-like data from healthy subjects, for enhanced training of deep learning frameworks. To ensure the faithfulness of our domain-aware COPD surrogates, the generated waveforms are examined through both flow waveforms and photoplethysmography (PPG) waveforms (as a proxy for intrathoracic pressure) in terms of duty cycle, sample entropy, FEV1/FVC ratios and flow-volume loops. The proposed simulator operates on healthy subjects and is able to generate FEV1/FVC obstruction ratios ranging from greater than 0.8 to less than 0.2, mirroring values that can observed in the full spectrum of real-world COPD. As a final stage of verification, a simple convolutional neural network is trained on surrogate data alone, and is used to accurately detect COPD in real-world patients. When training solely on surrogate data, and testing on real-world data, a comparison of true positive rate against false positive rate yields an area under the curve of 0.75, compared with 0.63 when training solely on real-world data.
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Affiliation(s)
- Harry J. Davies
- Department of Electrical and Electronic EngineeringImperial College LondonSW7 2BXLondonU.K.
| | - Ghena Hammour
- Department of Electrical and Electronic EngineeringImperial College LondonSW7 2BXLondonU.K.
| | - Hongjian Xiao
- Department of Electrical and Electronic EngineeringImperial College LondonSW7 2BXLondonU.K.
| | - Patrik Bachtiger
- National Heart and Lung InstituteImperial College LondonSW7 2BXLondonU.K.
| | | | | | - Nicholas S. Peters
- National Heart and Lung InstituteImperial College LondonSW7 2BXLondonU.K.
| | - Danilo P. Mandic
- Department of Electrical and Electronic EngineeringImperial College LondonSW7 2BXLondonU.K.
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2
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Charlton PH, Allen J, Bailón R, Baker S, Behar JA, Chen F, Clifford GD, Clifton DA, Davies HJ, Ding C, Ding X, Dunn J, Elgendi M, Ferdoushi M, Franklin D, Gil E, Hassan MF, Hernesniemi J, Hu X, Ji N, Khan Y, Kontaxis S, Korhonen I, Kyriacou PA, Laguna P, Lázaro J, Lee C, Levy J, Li Y, Liu C, Liu J, Lu L, Mandic DP, Marozas V, Mejía-Mejía E, Mukkamala R, Nitzan M, Pereira T, Poon CCY, Ramella-Roman JC, Saarinen H, Shandhi MMH, Shin H, Stansby G, Tamura T, Vehkaoja A, Wang WK, Zhang YT, Zhao N, Zheng D, Zhu T. The 2023 wearable photoplethysmography roadmap. Physiol Meas 2023; 44:111001. [PMID: 37494945 PMCID: PMC10686289 DOI: 10.1088/1361-6579/acead2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 04/04/2023] [Accepted: 07/26/2023] [Indexed: 07/28/2023]
Abstract
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.
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Affiliation(s)
- Peter H Charlton
- Department of Public Health and Primary Care, University of Cambridge, Cambridge, CB1 8RN, United Kingdom
- Research Centre for Biomedical Engineering, City, University of London, London, EC1V 0HB, United Kingdom
| | - John Allen
- Research Centre for Intelligent Healthcare, Coventry University, Coventry, CV1 5RW, United Kingdom
- Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, United Kingdom
| | - Raquel Bailón
- Biomedical Signal Interpretation and Computational Simulation (BSICoS) Group, Aragon Institute of Engineering Research (I3A), IIS Aragon, University of Zaragoza, E-50018 Zaragoza, Spain
- CIBER-BBN, Instituto de Salud Carlos III, C/Monforte de Lemos 3-5, E-28029 Madrid, Spain
| | - Stephanie Baker
- College of Science and Engineering, James Cook University, Cairns, 4878 Queensland, Australia
| | - Joachim A Behar
- Faculty of Biomedical Engineering, Technion Israel Institute of Technology, Haifa, 3200003, Israel
| | - Fei Chen
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055 Guandong, People’s Republic of China
| | - Gari D Clifford
- Department of Biomedical Informatics, Emory University, Atlanta, GA 30322, United States of America
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States of America
| | - David A Clifton
- Department of Engineering Science, University of Oxford, Oxford, OX3 7DQ, United Kingdom
| | - Harry J Davies
- Department of Electrical and Electronic Engineering, Imperial College London, London, SW7 2AZ, United Kingdom
| | - Cheng Ding
- Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States of America
- Department of Biomedical Engineering, Emory University, Atlanta, GA 30322, United States of America
| | - Xiaorong Ding
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, 611731, People’s Republic of China
| | - Jessilyn Dunn
- Department of Biomedical Engineering, Duke University, Durham, NC 27708-0187, United States of America
- Department of Biostatistics & Bioinformatics, Duke University, Durham, NC 27708-0187, United States of America
- Duke Clinical Research Institute, Durham, NC 27705-3976, United States of America
| | - Mohamed Elgendi
- Biomedical and Mobile Health Technology Laboratory, Department of Health Sciences and Technology, ETH Zurich, Zurich, 8008, Switzerland
| | - Munia Ferdoushi
- Department of Electrical and Computer Engineering, University of Southern California, 90089, Los Angeles, California, United States of America
- The Institute for Technology and Medical Systems (ITEMS), Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, United States of America
| | - Daniel Franklin
- Institute of Biomedical Engineering, Translational Biology & Engineering Program, Ted Rogers Centre for Heart Research, University of Toronto, Toronto, M5G 1M1, Canada
| | - Eduardo Gil
- Biomedical Signal Interpretation and Computational Simulation (BSICoS) Group, Aragon Institute of Engineering Research (I3A), IIS Aragon, University of Zaragoza, E-50018 Zaragoza, Spain
- CIBER-BBN, Instituto de Salud Carlos III, C/Monforte de Lemos 3-5, E-28029 Madrid, Spain
| | - Md Farhad Hassan
- Department of Electrical and Computer Engineering, University of Southern California, 90089, Los Angeles, California, United States of America
- The Institute for Technology and Medical Systems (ITEMS), Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, United States of America
| | - Jussi Hernesniemi
- Finnish Cardiovascular Research Center Tampere, Faculty of Medicine and Health Technology, Tampere University, Tampere, 33720, Finland
- Tampere Heart Hospital, Wellbeing Services County of Pirkanmaa, Tampere, 33520, Finland
| | - Xiao Hu
- Nell Hodgson Woodruff School of Nursing, Emory University, Atlanta, 30322, Georgia, United States of America
- Department of Biomedical Informatics, School of Medicine, Emory University, Atlanta, 30322, Georgia, United States of America
- Department of Computer Sciences, College of Arts and Sciences, Emory University, Atlanta, GA 30322, United States of America
| | - Nan Ji
- Hong Kong Center for Cerebrocardiovascular Health Engineering (COCHE), Hong Kong Science and Technology Park, Hong Kong, 999077, People’s Republic of China
| | - Yasser Khan
- Department of Electrical and Computer Engineering, University of Southern California, 90089, Los Angeles, California, United States of America
- The Institute for Technology and Medical Systems (ITEMS), Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, United States of America
| | - Spyridon Kontaxis
- Biomedical Signal Interpretation and Computational Simulation (BSICoS) Group, Aragon Institute of Engineering Research (I3A), IIS Aragon, University of Zaragoza, E-50018 Zaragoza, Spain
- CIBER-BBN, Instituto de Salud Carlos III, C/Monforte de Lemos 3-5, E-28029 Madrid, Spain
| | - Ilkka Korhonen
- Finnish Cardiovascular Research Center Tampere, Faculty of Medicine and Health Technology, Tampere University, Tampere, 33720, Finland
| | - Panicos A Kyriacou
- Research Centre for Biomedical Engineering, City, University of London, London, EC1V 0HB, United Kingdom
| | - Pablo Laguna
- Biomedical Signal Interpretation and Computational Simulation (BSICoS) Group, Aragon Institute of Engineering Research (I3A), IIS Aragon, University of Zaragoza, E-50018 Zaragoza, Spain
- CIBER-BBN, Instituto de Salud Carlos III, C/Monforte de Lemos 3-5, E-28029 Madrid, Spain
| | - Jesús Lázaro
- Biomedical Signal Interpretation and Computational Simulation (BSICoS) Group, Aragon Institute of Engineering Research (I3A), IIS Aragon, University of Zaragoza, E-50018 Zaragoza, Spain
- CIBER-BBN, Instituto de Salud Carlos III, C/Monforte de Lemos 3-5, E-28029 Madrid, Spain
| | - Chungkeun Lee
- Digital Health Devices Division, Medical Device Evaluation Department, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, 28159, Republic of Korea
| | - Jeremy Levy
- Faculty of Biomedical Engineering, Technion Israel Institute of Technology, Haifa, 3200003, Israel
- Faculty of Electrical and Computer Engineering, Technion Institute of Technology, Haifa, 3200003, Israel
| | - Yumin Li
- State Key Laboratory of Bioelectronics, School of Instrument Science and Engineering, Southeast University, Nanjing 210096, People’s Republic of China
| | - Chengyu Liu
- State Key Laboratory of Bioelectronics, School of Instrument Science and Engineering, Southeast University, Nanjing 210096, People’s Republic of China
| | - Jing Liu
- Analog Devices Inc, San Jose, CA 95124, United States of America
| | - Lei Lu
- Department of Engineering Science, University of Oxford, Oxford, OX3 7DQ, United Kingdom
| | - Danilo P Mandic
- Department of Electrical and Electronic Engineering, Imperial College London, London, SW7 2AZ, United Kingdom
| | - Vaidotas Marozas
- Department of Electronics Engineering, Kaunas University of Technology, 44249 Kaunas, Lithuania
- Biomedical Engineering Institute, Kaunas University of Technology, 44249 Kaunas, Lithuania
| | - Elisa Mejía-Mejía
- Research Centre for Biomedical Engineering, City, University of London, London, EC1V 0HB, United Kingdom
| | - Ramakrishna Mukkamala
- Department of Bioengineering and Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Meir Nitzan
- Department of Physics/Electro-Optic Engineering, Lev Academic Center, 91160 Jerusalem, Israel
| | - Tania Pereira
- INESC TEC—Institute for Systems and Computer Engineering, Technology and Science, Porto, 4200-465, Portugal
- Faculty of Engineering, University of Porto, Porto, 4200-465, Portugal
| | | | - Jessica C Ramella-Roman
- Department of Biomedical Engineering and Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33174, United States of America
| | - Harri Saarinen
- Tampere Heart Hospital, Wellbeing Services County of Pirkanmaa, Tampere, 33520, Finland
| | - Md Mobashir Hasan Shandhi
- Department of Biomedical Engineering, Duke University, Durham, NC 27708-0187, United States of America
| | - Hangsik Shin
- Department of Digital Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, 05505, Republic of Korea
| | - Gerard Stansby
- Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, United Kingdom
- Northern Vascular Centre, Freeman Hospital, Newcastle upon Tyne, NE7 7DN, United Kingdom
| | - Toshiyo Tamura
- Future Robotics Organization, Waseda University, Tokyo, 1698050, Japan
| | - Antti Vehkaoja
- Finnish Cardiovascular Research Center Tampere, Faculty of Medicine and Health Technology, Tampere University, Tampere, 33720, Finland
- PulseOn Ltd, Espoo, 02150, Finland
| | - Will Ke Wang
- Department of Biomedical Engineering, Duke University, Durham, NC 27708-0187, United States of America
| | - Yuan-Ting Zhang
- Hong Kong Center for Cerebrocardiovascular Health Engineering (COCHE), Hong Kong Science and Technology Park, Hong Kong, 999077, People’s Republic of China
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, 999077, People’s Republic of China
| | - Ni Zhao
- Department of Electronic Engineering, The Chinese University of Hong Kong, Hong Kong
| | - Dingchang Zheng
- Research Centre for Intelligent Healthcare, Coventry University, Coventry, CV1 5RW, United Kingdom
| | - Tingting Zhu
- Department of Engineering Science, University of Oxford, Oxford, OX3 7DQ, United Kingdom
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Park J, Seok HS, Kim SS, Shin H. Photoplethysmogram Analysis and Applications: An Integrative Review. Front Physiol 2022; 12:808451. [PMID: 35300400 PMCID: PMC8920970 DOI: 10.3389/fphys.2021.808451] [Citation(s) in RCA: 49] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 12/21/2021] [Indexed: 12/03/2022] Open
Abstract
Beyond its use in a clinical environment, photoplethysmogram (PPG) is increasingly used for measuring the physiological state of an individual in daily life. This review aims to examine existing research on photoplethysmogram concerning its generation mechanisms, measurement principles, clinical applications, noise definition, pre-processing techniques, feature detection techniques, and post-processing techniques for photoplethysmogram processing, especially from an engineering point of view. We performed an extensive search with the PubMed, Google Scholar, Institute of Electrical and Electronics Engineers (IEEE), ScienceDirect, and Web of Science databases. Exclusion conditions did not include the year of publication, but articles not published in English were excluded. Based on 118 articles, we identified four main topics of enabling PPG: (A) PPG waveform, (B) PPG features and clinical applications including basic features based on the original PPG waveform, combined features of PPG, and derivative features of PPG, (C) PPG noise including motion artifact baseline wandering and hypoperfusion, and (D) PPG signal processing including PPG preprocessing, PPG peak detection, and signal quality index. The application field of photoplethysmogram has been extending from the clinical to the mobile environment. Although there is no standardized pre-processing pipeline for PPG signal processing, as PPG data are acquired and accumulated in various ways, the recently proposed machine learning-based method is expected to offer a promising solution.
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Affiliation(s)
- Junyung Park
- Department of Biomedical Engineering, Chonnam National University, Yeosu, South Korea
| | - Hyeon Seok Seok
- Department of Biomedical Engineering, Chonnam National University, Yeosu, South Korea
| | - Sang-Su Kim
- Department of Biomedical Engineering, Chonnam National University, Yeosu, South Korea
| | - Hangsik Shin
- Department of Convergence Medicine, University of Ulsan College of Medicine, Asan Medical Center, Seoul, South Korea
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4
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Solé Morillo Á, Lambert Cause J, Baciu VE, da Silva B, Garcia-Naranjo JC, Stiens J. PPG EduKit: An Adjustable Photoplethysmography Evaluation System for Educational Activities. SENSORS 2022; 22:s22041389. [PMID: 35214290 PMCID: PMC8963096 DOI: 10.3390/s22041389] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/20/2022] [Accepted: 02/01/2022] [Indexed: 02/01/2023]
Abstract
The grown interest in healthcare applications has made biomedical engineering one of the fastest growing disciplines in recent years. Photoplethysmography (PPG) has gained popularity in recent years due to its versatility for noninvasive monitoring of vital signs such as heart rate, respiratory rate, blood oxygen saturation and blood pressure. In this work, an adjustable PPG-based educational device called PPG EduKit, which aims to facilitate the learning of the PPG technology for a wide range of engineering and medical disciplines is proposed. Through the use of this educational platform, the PPG signal can be understood, modified and implemented along with the extraction of its relevant physiological information from a didactic, intuitive and practical way. The PPG Edukit is evaluated for the extraction of physiological parameters such as heart rate and blood oxygen level, demonstrating how its features contribute to engineering and medical students to assimilate technical concepts in electrical circuits, biomedical instrumentation, and human physiology.
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Affiliation(s)
- Ángel Solé Morillo
- Department of Electronics and Informatics (ETRO), Vrije Universiteit Brussel (VUB), 1050 Brussels, Belgium; (V.-E.B.); (J.S.)
- Correspondence: (A.S.M.); (J.L.C.); (B.d.S.)
| | - Joan Lambert Cause
- Department of Electronics and Informatics (ETRO), Vrije Universiteit Brussel (VUB), 1050 Brussels, Belgium; (V.-E.B.); (J.S.)
- Department of Biomedical Engineering, Universidad de Oriente, Santiago de Cuba 90500, Cuba
- Correspondence: (A.S.M.); (J.L.C.); (B.d.S.)
| | - Vlad-Eusebiu Baciu
- Department of Electronics and Informatics (ETRO), Vrije Universiteit Brussel (VUB), 1050 Brussels, Belgium; (V.-E.B.); (J.S.)
| | - Bruno da Silva
- Department of Electronics and Informatics (ETRO), Vrije Universiteit Brussel (VUB), 1050 Brussels, Belgium; (V.-E.B.); (J.S.)
- Correspondence: (A.S.M.); (J.L.C.); (B.d.S.)
| | - Juan C. Garcia-Naranjo
- Biophysics and Medical Physics Center, Universidad de Oriente, Santiago de Cuba 90500, Cuba;
| | - Johan Stiens
- Department of Electronics and Informatics (ETRO), Vrije Universiteit Brussel (VUB), 1050 Brussels, Belgium; (V.-E.B.); (J.S.)
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Davies HJ, Bachtiger P, Williams I, Molyneaux PL, Peters NS, Mandic DP. Wearable In-Ear PPG: Detailed Respiratory Variations Enable Classification of COPD. IEEE Trans Biomed Eng 2022; 69:2390-2400. [PMID: 35077352 DOI: 10.1109/tbme.2022.3145688] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
An ability to extract detailed spirometry-like breath-ing waveforms from wearable sensors promises to greatly improve respiratory health monitoring. Photoplethysmography (PPG) has been researched in depth for estimation of respiration rate, given that it varies with respiration through overall intensity, pulse amplitude and pulse interval. We compare and contrast the extraction of these three respiratory modes from both the ear canal and finger and show a marked improvement in the respiratory power for respiration induced intensity variations and pulse amplitude variations when recording from the ear canal. We next employ a data driven multi-scale method, noise assisted multivariate empirical mode decomposition (NA-MEMD), which allows for simultaneous analysis of all three respiratory modes to extract detailed respiratory waveforms from in-ear PPG. For rigour, we considered in-ear PPG recordings from healthy subjects, both older and young, patients with chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF) and healthy subjects with artificially obstructed breathing. Specific in-ear PPG waveform changes are observed for COPD, such as a decreased inspiratory duty cycle and an increased inspiratory magnitude, when compared with expiratory magnitude. These differences are used to classify COPD from healthy and IPF waveforms with a sensitivity of 87% and an overall accuracy of 92%. Our findings indicate the promise of in-ear PPG for COPD screening and unobtrusive respiratory monitoring in ambulatory scenarios and in consumer wearables.
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Keogh C, Drummond GB, Bates A, Mann J, Arvind DK. A conceptual model for changes in finger photoplethysmograph signals caused by hand posture and isothermic regulation. Physiol Meas 2022; 43. [PMID: 34986476 DOI: 10.1088/1361-6579/ac482e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 01/05/2022] [Indexed: 11/12/2022]
Abstract
OBJECTIVE To observe changes in baseline and pulsatile light absorbance (photoplethysmograph, PPG) in the finger-tip, by raising the hand above the horizontal plane in recumbent subjects. We applied current knowledge of the circulation to the finger-tip, particularly arteriovenous anastomoses (AVAs), and the physiology of the venous circulation. APPROACH We studied healthy young volunteers in a quiet thermoneutral environment. A finger plethysmograph on the non-dominant hand recorded transmission of red and infra-red light, and the values were converted into absorbance to allow comparisons within and between subjects. Breathing movements were recorded unobtrusively to assess any effect on absorbance and the pulse amplitude of the signals. All body movements were passive: the study arm was elevated in a trough to about 40° above the horizontal plane. The following conditions were studied, each for 15 minutes, using the last 10 minutes for analysis: recumbent, study arm elevated, study arm horizontal, and both legs elevated by 40°. MAIN RESULTS There was a substantial time-related effect, and considerable variation between subjects. Arm elevation reduced red light absorbance and increased the range of amplitudes of the PPG waveform: only in subjects with large absorbances, did waveform amplitude increase. The other main effect was that spontaneous, thermoregulatory decreases in absorbance were associated with decreases in waveform amplitude. SIGNIFICANCE Finger-tip vessels distend with blood when AVAs open. The vessels pulsate more strongly if venous collapse allows the vessels to become more compliant. The postcapillary circulation is likely to be an important source of pulsation.
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Affiliation(s)
- Cameron Keogh
- Anaesthesia Critical Care and Pain Medicine, The University of Edinburgh School of Clinical Sciences, Old College, South Bridge, Edinburgh, Edinburgh, EH8 9YL, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Gordon B Drummond
- Department of Anaesthesia, Critical Care and Pain Medicine, The University of Edinburgh Division of Health Sciences, Old College, South Bridge, Edinburgh, Edinburgh, EH8 9YL, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Andrew Bates
- Centre for Speckled Computing, University of Edinburgh College of Science and Engineering, Old College, South Bridge, Edinburgh, EH8 9YL, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Janek Mann
- Centre for Speckled Computing, University of Edinburgh College of Science & Engineering , Old College, South Bridge, Edinburgh, EH8 9YL, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - D K Arvind
- Centre for Speckled Computing, The University of Edinburgh College of Science and Engineering, Old College, South Bridge, Edinburgh, Edinburgh, EH8 9YL, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
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De Pinho Ferreira N, Gehin C, Massot B. A Review of Methods for Non-Invasive Heart Rate Measurement on Wrist. Ing Rech Biomed 2021. [DOI: 10.1016/j.irbm.2020.04.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Shin H, Park J, Seok HS, Kim SS. Photoplethysmogram analysis and applications: An Integrative Review (Preprint). JMIR BIOMEDICAL ENGINEERING 2020. [DOI: 10.2196/25567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Khoo MCK, Chalacheva P. Respiratory modulation of peripheral vasoconstriction: a modeling perspective. J Appl Physiol (1985) 2019; 127:1177-1186. [DOI: 10.1152/japplphysiol.00111.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Although respiratory sinus arrhythmia and blood pressure variability have been investigated extensively, there have been far fewer studies of the respiratory modulation of peripheral blood flow in humans. Existing studies have been based primarily on noninvasive measurements using digit photoplethysmography and laser-Doppler flowmetry. The cumulative knowledge derived from these studies suggests that respiration can contribute to fluctuations in peripheral blood flow and volume through a combination of mechanical, hemodynamic, and neural mechanisms. However, the most convincing evidence suggests that the sympathetic nervous system plays the predominant role under normal, resting conditions. This mini-review provides a consolidation and interpretation of the key findings reported in this topical area. Given the need to extract dynamic information from noninvasive measurements under largely “closed-loop” conditions, we propose that the application of analytical tools based on systems theory and mathematical modeling can be of great utility in future studies. In particular, we present an example of how the transfer relation linking respiration to peripheral vascular conductance can be derived using measurements recorded during spontaneous breathing, spontaneous sighs, and ventilator-induced sighs.
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Affiliation(s)
- Michael C. K. Khoo
- Biomedical Engineering Department, University of Southern California, Los Angeles, California
| | - Patjanaporn Chalacheva
- Biomedical Engineering Department, University of Southern California, Los Angeles, California
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Lee JH, Kim EH, Jang YE, Kim HS, Kim JT. Fluid responsiveness in the pediatric population. Korean J Anesthesiol 2019; 72:429-440. [PMID: 31591858 PMCID: PMC6781210 DOI: 10.4097/kja.19305] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 09/01/2019] [Indexed: 01/23/2023] Open
Abstract
It is challenging to predict fluid responsiveness, that is, whether the cardiac index or stroke volume index would be increased by fluid administration, in the pediatric population. Previous studies on fluid responsiveness have assessed several variables derived from pressure wave measurements, plethysmography (pulse oximeter plethysmograph amplitude variation), ultrasonography, bioreactance data, and various combined methods. However, only the respiratory variation of aortic blood flow peak velocity has consistently shown a predictive ability in pediatric patients. For the prediction of fluid responsiveness in children, flow- or volume-dependent, noninvasive variables are more promising than pressure-dependent, invasive variables. This article reviews various potential variables for the prediction of fluid responsiveness in the pediatric population. Differences in anatomic and physiologic characteristics between the pediatric and adult populations are covered. In addition, some important considerations are discussed for future studies on fluid responsiveness in the pediatric population.
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Affiliation(s)
- Ji-Hyun Lee
- Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Eun-Hee Kim
- Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Young-Eun Jang
- Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Hee-Soo Kim
- Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Jin-Tae Kim
- Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
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van Gastel M, Stuijk S, de Haan G. Robust respiration detection from remote photoplethysmography. BIOMEDICAL OPTICS EXPRESS 2016; 7:4941-4957. [PMID: 28018717 PMCID: PMC5175543 DOI: 10.1364/boe.7.004941] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 09/30/2016] [Accepted: 10/06/2016] [Indexed: 05/10/2023]
Abstract
Continuous monitoring of respiration is essential for early detection of critical illness. Current methods require sensors attached to the body and/or are not robust to subject motion. Alternative camera-based solutions have been presented using motion vectors and remote photoplethysmography. In this work, we present a non-contact camera-based method to detect respiration, which can operate in both visible and dark lighting conditions by detecting the respiratory-induced colour differences of the skin. We make use of the close similarity between skin colour variations caused by the beating of the heart and those caused by respiration, leading to a much improved signal quality compared to single-channel approaches. Essentially, we propose to find the linear combination of colour channels which suppresses the distortions best in a frequency band including pulse rate, and subsequently we use this same linear combination to extract the respiratory signal in a lower frequency band. Evaluation results obtained from recordings on healthy subjects which perform challenging scenarios, including motion, show that respiration can be accurately detected over the entire range of respiratory frequencies, with a correlation coefficient of 0.96 in visible light and 0.98 in infrared, compared to 0.86 with the best-performing non-contact benchmark algorithm. Furthermore, evaluation on a set of videos recorded in a Neonatal Intensive Care Unit (NICU) shows that this technique looks promising as a future alternative to current contact-sensors showing a correlation coefficient of 0.87.
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Affiliation(s)
- Mark van Gastel
- Department of Electrical Engineering, Eindhoven University of Technology, PO Box 513, 5600MB, Eindhoven, The
Netherlands
| | - Sander Stuijk
- Department of Electrical Engineering, Eindhoven University of Technology, PO Box 513, 5600MB, Eindhoven, The
Netherlands
| | - Gerard de Haan
- Department of Electrical Engineering, Eindhoven University of Technology, PO Box 513, 5600MB, Eindhoven, The
Netherlands
- Philips Research, High Tech Campus 36, 5656AE, Eindhoven, The
Netherlands
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Belhaj AM, Phillips JP, Kyriacou PA, Langford RM. Comparison of non-invasive peripheral venous saturations with venous blood co-oximetry. J Clin Monit Comput 2016; 31:1213-1220. [PMID: 27873173 PMCID: PMC5655584 DOI: 10.1007/s10877-016-9959-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Accepted: 10/11/2016] [Indexed: 11/20/2022]
Abstract
The estimation of venous oxygen saturations using photoplethysmography (PPG) may be useful as a noninvasive continuous method of detecting changes in regional oxygen supply and demand (e.g. in the splanchnic circulation). The aim of this research was to compare PPG-derived peripheral venous oxygen saturations directly with venous saturation measured from co-oximetry blood samples, to assess the feasibility of non-invasive local venous oxygen saturation. This paper comprises two similar studies: one in healthy spontaneously-breathing volunteers and one in mechanically ventilated anaesthetised patients. In both studies, PPG-derived estimates of peripheral venous oxygen saturations (SxvO2) were compared with co-oximetry samples (ScovO2) of venous blood from the dorsum of the hand. The results were analysed and correlation between the PPG-derived results and co-oximetry was tested for. In the volunteer subjects,moderate correlation (r = 0.81) was seen between SxvO2 values and co-oximetry derived venous saturations (ScovO2), with a mean (±SD) difference of +5.65 ± 14.3% observed between the two methods. In the anaesthetised patients SxvO2 values were only 3.81% lower than SpO2 and tended to underestimate venous saturation (mean difference = –2.67 ± 5.89%) while correlating weakly with ScovO2 (r = 0.10). The results suggest that significant refinement of the technique is needed to sufficiently improve accuracy to produce clinically meaningful measurement of peripheral venous oxygen saturation. In anaesthetised patients the use of the technique may be severely limited by cutaneous arteriovenous shunting.
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Affiliation(s)
- A M Belhaj
- Southend University Hospital, Prittlewell Chase, Westcliff-on-Sea, Essex, SS0 0RY, UK
| | - J P Phillips
- Research Centre for Biomedical Engineering, City, University of London, Northampton Square, London, EC1V 0HB, UK.
| | - P A Kyriacou
- Research Centre for Biomedical Engineering, City, University of London, Northampton Square, London, EC1V 0HB, UK
| | - R M Langford
- Pain and Anaesthesia Research Centre, St Bartholomew's Hospital, West Smithfield, London, ECIA 7BE, UK
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Respiratory variations in the photoplethysmographic waveform amplitude depend on type of pulse oximetry device. J Clin Monit Comput 2015; 30:317-25. [DOI: 10.1007/s10877-015-9720-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 06/05/2015] [Indexed: 10/23/2022]
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Hickey M, Phillips JP, Kyriacou PA. The effect of vascular changes on the photoplethysmographic signal at different hand elevations. Physiol Meas 2015; 36:425-40. [PMID: 25652182 DOI: 10.1088/0967-3334/36/3/425] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In order to further understand the contribution of venous and arterial effects to the photoplethysmographic (PPG) signal, recordings were made from 20 healthy volunteer subjects during an exercise in which the right hand was raised and lowered with reference to heart level. Red (R) and infrared (IR) PPG signals were obtained from the right index finger using a custom-made PPG processing system. Laser Doppler flowmetry (LDF) signals were also recorded from an adjacent fingertip. The signals were compared with simultaneous PPG signals obtained from the left index finger. On lowering the hand to 50 cm below heart level, both ac and dc PPG amplitudes from the finger decreased (e.g. 18.70 and 63.15% decrease in infrared dc and ac signals respectively). The decrease in dc amplitude most likely corresponded to increased venous volume, while the decrease in ac PPG amplitude was due to regulatory adjustments on the arterial side in response to venous distension. Conversely, ac and dc PPG amplitudes increased on raising the arm above heart level. Morphological changes in the ac PPG signal are thought to be due to vascular resistance changes, predominately venous, as the hand position is changed.
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Affiliation(s)
- M Hickey
- School of Mathematics, Computer Science and Engineering, City University London, London, EC1V 0HB, UK
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Shalom E, Noach S, Slovik Y, Nitzan M. Respiratory-induced vasoconstriction measured by light transmission and by laser Doppler signal. JOURNAL OF BIOPHOTONICS 2013; 6:631-636. [PMID: 22987841 DOI: 10.1002/jbio.201200097] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 08/08/2012] [Accepted: 08/13/2012] [Indexed: 06/01/2023]
Abstract
Changes in finger tissue blood volume (TBV) measured by light transmission and in laser Doppler flow (LDF) were obtained during long breathing (of 12 s period) and associated with the respiratory phases, inspiration and expiration. For fifteen out of sixteen subjects TBV and LDF started to decrease 0-2 s after the start of expiration and increased during inspiration but the start of increase occurred before the start of inspiration, showing that the respiratory-induced changes in TBV and LDF are mainly associated with the expiration. Decrease of TBV and LDF after expiration was also found during the inspiratory gasps
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Affiliation(s)
- Eran Shalom
- Department of Applied Physics/Medical Engineering, Jerusalem College of Technology, 21, Havaad Haleumi Street, POB 16031, Jerusalem 91160, Israel
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Phillips JP, Belhaj A, Shafqat K, Langford RM, Shelley KH, Kyriacou PA. Modulation of finger photoplethysmographic traces during forced respiration: venous blood in motion? ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2013; 2012:3644-7. [PMID: 23366717 DOI: 10.1109/embc.2012.6346756] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Photoplethysmographic (PPG) signals were recorded from the fingers of 10 healthy volunteers during forced respiratory inspiration. The aim of this pilot study was to assess the effect of negative airway pressure on the blood volumes within the tissue bed of the finger, and the resultant modulation of PPG signals. The acquired signals were analysed and oxygen saturations estimated from the frequency spectra in the cardiac and respiratory frequency ranges. Assuming that respiratory modulation affects blood volumes in veins to a greater extent than in arteries, the local venous oxygen saturation was estimated. Estimated venous oxygen saturation was found to be 3.1% (±4.2%) lower than the estimated arterial saturation.
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Affiliation(s)
- Justin P Phillips
- School of Engineering and Mathematical Sciences, City University London, EC1V 0HB, UK.
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Monnet X, Guérin L, Jozwiak M, Bataille A, Julien F, Richard C, Teboul JL. Pleth variability index is a weak predictor of fluid responsiveness in patients receiving norepinephrine. Br J Anaesth 2012; 110:207-13. [PMID: 23103777 DOI: 10.1093/bja/aes373] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND In patients receiving an infusion of norepinephrine, the relationship between the amplitude of the oximeter plethysmographic waveform and stroke volume may be variable and quality of the waveform might be reduced, compared with patients not receiving norepinephrine. We assessed the reliability of the pleth variability index (PVI), an automatic measurement of the respiratory variation of the plethysmographic waveform, for predicting fluid responsiveness in patients receiving norepinephrine infusions. METHODS We measured the response of cardiac index (transpulmonary thermodilution) to i.v. fluid administration in 42 critically ill patients receiving norepinephrine. Patients with arrhythmias, spontaneous breathing, tidal volume <8 ml kg(-1), and respiratory system compliance <30 ml cm H(2)O(-1) were excluded. Before fluid administration, we recorded the arterial pulse pressure variation (PPV) and pulse contour analysis-derived stroke volume variation (SVV, PiCCO2) and PVI (Masimo Radical-7). RESULTS In seven patients, the plethysmographic signal could not be obtained. Among the 35 remaining patients [mean SAPS II score=77 (sd=17)], i.v. fluid increased cardiac index ≥15% in 15 'responders'. A baseline PVI ≥16% predicted fluid responsiveness with a sensitivity of 47 (inter-quartile range=21-73)% and a specificity of 90 (68-99)%. The area under the receiver operating characteristic curve was significantly lower for PVI [0.68 (0.09)] than for PPV and SVV [0.93 (0.06) and 0.89 (0.07), respectively]. Considering all pairs of measurements, PVI was correlated with PPV (r(2)=0.27). The fluid-induced changes in PVI and PPV were not significantly correlated. CONCLUSIONS PVI was less reliable than PPV and SVV for predicting fluid responsiveness in critically ill patients receiving norepinephrine. In addition, PVI could not be measured in a significant proportion of patients. This suggests that PVI is not useful in patients receiving norepinephrine.
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Affiliation(s)
- X Monnet
- Hôpitaux universitaires Paris-Sud, Hôpital de Bicêtre, service de réanimation médicale, 78, rue du Général Leclerc, Le Kremlin-Bicêtre F-94270, France.
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Meredith DJ, Clifton D, Charlton P, Brooks J, Pugh CW, Tarassenko L. Photoplethysmographic derivation of respiratory rate: a review of relevant physiology. J Med Eng Technol 2011; 36:1-7. [PMID: 22185462 DOI: 10.3109/03091902.2011.638965] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
An abnormal respiratory rate is often the earliest sign of critical illness. A reliable estimate of respiratory rate is vital in the application of remote telemonitoring systems, which may facilitate early supported discharge from hospital or prompt recognition of physiological deterioration in high-risk patient groups. Traditional approaches use analysis of respiratory sinus arrhythmia from the electrocardiogram (ECG), but this phenomenon is predominantly limited to the young and healthy. Analysis of the photoplethysmogram (PPG) waveform offers an alternative means of non-invasive respiratory rate monitoring, but further development is required to enable reliable estimates. This review conceptualizes the challenge by discussing the effect of respiration on the PPG waveform and the key physiological mechanisms that underpin the derivation of respiratory rate from the PPG.
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Affiliation(s)
- D J Meredith
- Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7BN, UK.
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Lee C, Sik Shin H, Lee M. Relations between ac-dc components and optical path length in photoplethysmography. JOURNAL OF BIOMEDICAL OPTICS 2011; 16:077012. [PMID: 21806292 DOI: 10.1117/1.3600769] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Photoplethysmography is used in various areas such as vital sign measurement, vascular characteristics analysis, and autonomic nervous system assessment. Photoplethysmographic signals are composed of ac and dc, but it is difficult to find research about the interaction of photoplethysmographic components. This study suggested a model equation combining two Lambert-Beer equations at the onset and peak points of photoplethysmography to evaluate ac characteristics, and verified the model equation through simulation and experiment. In the suggested equation, ac was dependent on dc and optical path length. In the simulation, dc was inversely proportionate to ac sensitivity (slope), and ac and optical path length were proportionate. When dc increased from 10% to 90%, stabilized ac decreased from 1 to 0.89 ± 0.21, and when optical path length increased from 10% to 90%, stabilized ac increased from 1 to 1.53 ± 0.40.
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Affiliation(s)
- Chungkeun Lee
- Yonsei University, School of Electrical and Electronic Engineering, Sinchon-dong, Seodaemoon-gu, Seoul, 120-749 Republic of Korea
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Fingertip photoplethysmographic waveform variability and systemic vascular resistance in intensive care unit patients. Med Biol Eng Comput 2011; 49:859-66. [PMID: 21340639 DOI: 10.1007/s11517-011-0749-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Accepted: 01/31/2011] [Indexed: 12/31/2022]
Abstract
Low frequency variability in the fingertip photoplethysmogram (PPG) waveform has been utilized for inferring sympathetic vascular control, but its relationship with a quantitative measure of vascular tone has not been established. In this study, we examined the association between fingertip PPG waveform variability (PPGV) and systemic vascular resistance (SVR) obtained from thermodilution cardiac output (CO) and intra-arterial pressure measurements in 48 post cardiac surgery intensive care unit patients. Among the hemodynamic measurements, both CO (P < 0.05) and SVR (P < 0.0001) had statistically significant relationships with the normalized low frequency power (LF(nu)) of PPGV. The LF(nu) of baseline PPGV had moderate but significant positive correlation with SVR (r = 0.54, P < 0.0001), and a value below 52.5 nu was able to identify SVR < 900 dyn s cm⁻⁵ with sensitivity of 59% and specificity of 95%. The results have provided quantitative evidence to confirm the link between fingertip PPGV and sympathetic vascular control. Suppression of LF vasomotor waves leading to dominance of respiration-related HF fluctuations in the fingertip circulation was a specific (though not sensitive) marker of systemic vasodilatation, which could be potentially utilized for the assessment of critical care patients.
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Nilsson L, Goscinski T, Lindenberger M, Länne T, Johansson A. Respiratory variations in the photoplethysmographic waveform: acute hypovolaemia during spontaneous breathing is not detected. Physiol Meas 2010; 31:953-62. [DOI: 10.1088/0967-3334/31/7/006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Jeong I, Jun S, Um D, Oh J, Yoon H. Non-invasive estimation of systolic blood pressure and diastolic blood pressure using photoplethysmograph components. Yonsei Med J 2010; 51:345-53. [PMID: 20376886 PMCID: PMC2852789 DOI: 10.3349/ymj.2010.51.3.345] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
PURPOSE Photoplethysmography (PPG) is a noninvasive optical technology that detects changes in blood volume in the vascular system. This study aimed to investigate the possibilities of monitoring the cardiovascular system status by using PPG. MATERIALS AND METHODS Forced hemodynamic changes were induced using cardiac stimulants; dopamine and epinephrine, and PPG components were recorded by a noninvasive method at the peripheral blood vessels. The results were compared among 6 dogs. Endotracheal intubation was performed after an intramuscular injection of 25 mg/kg ketamine sulfate, and anesthesia was maintained with 2% enflurane. After stabilizing the animals for 15 min, 16 mg/mL diluted dopamine was injected into a vein for 2 min at 20 microg/kg min(-1) by using an infusion pump. Thereafter, the infusion pump was stopped, and 1 mg epinephrine was injected intravenously. Fluid administration was controlled to minimize preload change in blood pressure. RESULTS After stimulant administration, systolic blood pressure (SBP) and diastolic blood pressures (DBP) increased. The direct current (DC) component, which reflects changes in blood volume, decreased while the alternating current (AC) component, which reflects changes in vascular compliance and resistance, increased. The correlation coefficient between SBP and the foot of the DC component was 0.939 (p < 0.01), while it was 0.942 (p < 0.01) for DBP and the peak of the DC component. The AC component could predict the increase in vascular resistance from a stable pulse blood volume, even with increased pulse pressure. CONCLUSION These results support the possibility that PPG components may be used for easy and noninvasive measurement of hemodynamic changes in the cardiovascular system.
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Affiliation(s)
- Incheol Jeong
- Department of Biomedical Engineering, Yonsei University, Wonju, Korea
| | - Sukhwan Jun
- Department of Biomedical Engineering, Yonsei University, Wonju, Korea
| | - Daeja Um
- Department of Anesthesiology, Yonsei University, Wonju, Korea
| | - Joonghwan Oh
- Department of Thoracic & Cardiovascular Surgery, Yonsei University, Wonju, Korea
| | - Hyungro Yoon
- Department of Biomedical Engineering, Yonsei University, Wonju, Korea
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Li J, Jin J, Chen X, Sun W, Guo P. Comparison of respiratory-induced variations in photoplethysmographic signals. Physiol Meas 2010; 31:415-25. [DOI: 10.1088/0967-3334/31/3/009] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Selvaraj N, Jaryal AK, Santhosh J, Deepak KK, Anand S. Influence of respiratory rate on the variability of blood volume pulse characteristics. J Med Eng Technol 2009; 33:370-5. [DOI: 10.1080/03091900802454483] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Low-frequency changes in finger volume in patients after surgery, related to respiration and venous pressure. Eur J Anaesthesiol 2009; 26:9-16. [PMID: 19122545 DOI: 10.1097/eja.0b013e328318c6bd] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND AND OBJECTIVE In patients after surgery, we observed large-amplitude low-frequency changes in digital plethysmograph measurements when DC coupling of the signal was used. We set out to assess factors that might contribute to these events and in particular to test the possibility that low-frequency signals could be used to assess respiratory disturbances. METHODS We recorded values in 23 patients who had undergone gynaecological surgery. We measured nasal flow, abdominal pressure (by urinary catheter), venous pressure in the hand, and DC-coupled optical transmission plethysmography. Signals were replayed and analysed to assess the incidence of specific patterns of events. RESULTS Most patients received morphine for postoperative analgesia. Respiratory irregularity and expiratory muscle action were very frequent. Increases in abdominal pressure during expiration caused increases in venous pressure and pulsation. In 12 out of 23 patients, a characteristic response consistent with vasoconstriction was noted after increases in breath size, and, in seven patients, very-low-frequency (0.2-0.7 Hz) oscillations of finger volume were present that appeared unrelated to respiratory events. Patients who did not receive morphine had very different plethysmograph patterns, with significantly smaller pulse amplitude. CONCLUSION Low-frequency changes in finger volume can be simply obtained and provide considerable information about peripheral circulatory dynamics. Diverse patterns can be recognized, but the range of responses suggests that current techniques cannot be used alone to assess cardiorespiratory status. However, a combination of plethysmography with respiratory measurements shows characteristic events.
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Popovic D, King C, Guerrero M, Levendowski DJ, Henninger D, Westbrook PR. Validation of forehead venous pressure as a measure of respiratory effort for the diagnosis of sleep apnea. J Clin Monit Comput 2008; 23:1-10. [PMID: 19116764 DOI: 10.1007/s10877-008-9154-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Accepted: 11/25/2008] [Indexed: 11/28/2022]
Abstract
OBJECTIVES The aim of the study was to validate the measurement of Forehead Venous Pressure derived from a single site on the forehead as an alternative to esophageal manometry and respiratory effort bands in the differential diagnosis of sleep apnea. METHODS Fourteen subjects underwent a laboratory polysomnography concurrently with ARES Unicorder at Walter Reed Army Medical Center. Two-hundred respiratory events were selected by a scorer boarded in sleep medicine and classified into six event categories used in the differential diagnosis of sleep disordered breathing. Four sets of events were prepared, each containing airflow and one of four measures of respiratory effort (i.e., esophageal manometer, chest and abdomen bands, and forehead venous pressure). A second board-certified scorer scored each set of events twice while blinded to the type of the effort signal. RESULTS The inter-rater Kappa scores across all event types indicated all four effort signals provided moderate agreement (kappa = 0.43-0.47). When comparing the intra-rater Kappa scores, the chest belt was superior (kappa = 0.88) to the esophageal manometry, FVP and abdomen belt (kappa = 0.78-0.82). The Kappa scores for the intra-rater comparison with the esophageal serving as the gold standard, FVP abdomen and chest all showed near perfect agreement (kappa = 0.81-0.86). The esophageal manometer and FVP provided slightly better inter-rater agreement in the detection of both obstructive hypopneas and apneas as compared to the chest and abdomen belts. There was a 20-30% drop in inter-rater reliability in the detection of flow-limitation and ventilation-change events compared to obstructive events, and all effort signals showed poor inter-rater agreement for central and mixed events. CONCLUSIONS The results of the study suggest that the FVP can serve as an alternative to respiratory bands in the differential diagnosis of sleep disordered breathing, and in the recognition of patients appropriate for bilevel continuous positive airway pressure devices.
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Abstract
Photoplethysmography (PPG) is a simple and low-cost optical technique that can be used to detect blood volume changes in the microvascular bed of tissue. It is often used non-invasively to make measurements at the skin surface. The PPG waveform comprises a pulsatile ('AC') physiological waveform attributed to cardiac synchronous changes in the blood volume with each heart beat, and is superimposed on a slowly varying ('DC') baseline with various lower frequency components attributed to respiration, sympathetic nervous system activity and thermoregulation. Although the origins of the components of the PPG signal are not fully understood, it is generally accepted that they can provide valuable information about the cardiovascular system. There has been a resurgence of interest in the technique in recent years, driven by the demand for low cost, simple and portable technology for the primary care and community based clinical settings, the wide availability of low cost and small semiconductor components, and the advancement of computer-based pulse wave analysis techniques. The PPG technology has been used in a wide range of commercially available medical devices for measuring oxygen saturation, blood pressure and cardiac output, assessing autonomic function and also detecting peripheral vascular disease. The introductory sections of the topical review describe the basic principle of operation and interaction of light with tissue, early and recent history of PPG, instrumentation, measurement protocol, and pulse wave analysis. The review then focuses on the applications of PPG in clinical physiological measurements, including clinical physiological monitoring, vascular assessment and autonomic function.
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Affiliation(s)
- John Allen
- Regional Medical Physics Department, Freeman Hospital, Newcastle upon Tyne, UK.
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Nilsson L. Respiratory monitoring using reflection mode photoplethysmography: clinical and physiological aspects. Acta Anaesthesiol Scand 2007. [DOI: 10.1111/j.1399-6576.2006.01198.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Nilsson L, Goscinski T, Johansson A, Lindberg LG, Kalman S. Age and gender do not influence the ability to detect respiration by photoplethysmography. J Clin Monit Comput 2006; 20:431-6. [PMID: 17033878 DOI: 10.1007/s10877-006-9050-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2006] [Accepted: 09/07/2006] [Indexed: 11/30/2022]
Abstract
OBJECTIVE The non-invasive technique photoplethysmography (PPG) can detect changes in blood volume and perfusion in a tissue. Respiration causes variations in the peripheral circulation, making it possible to monitor breaths using an optical sensor attached to the skin. The respiratory-synchronous part of the PPG signal (PPGr) has been used to monitor respiration during anaesthesia, and in postoperative and neonatal care. Studies addressing possible differences in PPGr signal characteristics depending on gender or age are lacking. METHODS We studied three groups of 16 healthy subjects each during normal breathing; young males, old males and young females, and calculated the concordance between PPGr, derived from a reflection mode PPG sensor on the forearm, and a reference CO(2 )signal. The concordance was quantified by using a squared coherence analysis. Time delay between the two signals was calculated. In this process, we compared three different methods for calculating time delay. RESULTS Coherence values >or=0.92 were seen for all three groups without any significant differences depending on age or gender (p = 0.67). Comparison between the three different methods for calculating time delay showed a correlation r = 0.93. CONCLUSIONS These results demonstrate clinically important information implying the possibility to register qualitative PPGr signals for respiration monitoring, regardless of age and gender.
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Affiliation(s)
- Lena Nilsson
- Department of Anaesthesiology and Intensive Care, Linköping University Hospital, Linköping, S-581 85, Sweden.
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Shelley KH, Jablonka DH, Awad AA, Stout RG, Rezkanna H, Silverman DG. What Is the Best Site for Measuring the Effect of Ventilation on the Pulse Oximeter Waveform? Anesth Analg 2006; 103:372-7, table of contents. [PMID: 16861419 DOI: 10.1213/01.ane.0000222477.67637.17] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The cardiac pulse is the predominant feature of the pulse oximeter (plethysmographic) waveform. Less obvious is the effect of ventilation on the waveform. There have been efforts to measure the effect of ventilation on the waveform to determine respiratory rate, tidal volume, and blood volume. We measured the relative strength of the effect of ventilation on the reflective plethysmographic waveform at three different sites: the finger, ear, and forehead. The plethysmographic waveforms from 18 patients undergoing positive pressure ventilation during surgery and 10 patients spontaneously breathing during renal dialysis were collected. The respiratory signal was isolated from the waveform using spectral analysis. It was found that the respiratory signal in the pulse oximeter waveform was more than 10 times stronger in the region of the head when compared with the finger. This was true with both controlled positive pressure ventilation and spontaneous breathing. A significant correlation was demonstrated between the estimated blood loss from surgical procedures and the impact of ventilation on ear plethysmographic data (r(s) = 0.624, P = 0.006).
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Affiliation(s)
- Kirk H Shelley
- Department of Anesthesiology, Yale University, New Haven, Connecticut, USA.
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Yoon G, Lee JY, Jeon KJ, Park KK, Kim HS. Development of a Compact Home Health Monitor for Telemedicine. Telemed J E Health 2005; 11:660-7. [PMID: 16430385 DOI: 10.1089/tmj.2005.11.660] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A compact and easy-to-use home health monitor was developed. A palm-size health monitor contained a finger probe as sensor unit. In the finger probe, light from a light emitting diode (LED) array was illuminated on a finger nail bed, and transmitted light was measured to obtain photoplethysmography (PPG) signals. Hematocrit, pulse, respiration rate, and saturated oxygen in arterial blood (SpO(2)) were measured simultaneously from PPGs using five different wavelengths: 569, 660, 805, 904, and 975 nm. To predict hematocrit, a dedicated algorithm was used based on scattering theory of red blood cells using these wavelengths. Preliminary clinical tests showed that the achieved percent errors were +/- 8.2% for hematocrit when tested with 549 persons (N = 549). Digital filtering techniques were used to extract respiratory information from a single PPG signal. SpO(2) was predicted on the basis of the ratio of the wavelengths 660 nm and 940 nm. The accuracies were within clinically acceptable errors. In addition, the compact home health monitor included a blood pressure monitoring unit. For convenient and simultaneous measurement with the other previously mentioned signals, blood pressure was measured on a finger. An air cuff was installed on the same finger where PPGs were measured. Achieved mean differences were +/- 3.8 mmHg for systole and +/- 5.1 mmHg for diastole. One can use the palm-size monitor simply by inserting a finger into the home health monitor that is suitable for telemedicine.
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Affiliation(s)
- Gilwon Yoon
- Department of Electronic & Information, Seoul National University of Technology, Seoul, Korea.
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Nilsson L, Johansson A, Kalman S. Respiration can be monitored by photoplethysmography with high sensitivity and specificity regardless of anaesthesia and ventilatory mode. Acta Anaesthesiol Scand 2005; 49:1157-62. [PMID: 16095458 DOI: 10.1111/j.1399-6576.2005.00721.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND Photoplethysmography (PPG) is a non-invasive optical technique used, for instance, in pulse oximetry. Beside the pulse synchronous component, PPG has a respiratory synchronous variation (PPGr). Efforts have been made to utilize this component for indirect monitoring of respiratory rate and volume. Assessment of the clinical usefulness as well as of the physiological background of PPGr is required. We evaluated if anaesthesia and positive-pressure ventilation would affect PPGr. METHODS We recorded reflection mode PPGr, at the forearm, and the respiratory synchronous changes in central venous pressure (CVP), peripheral venous pressure (PVP) and arterial blood pressure (ABP) in 12 patients. Recordings for each patient were made on three occasions: awake with spontaneous breathing; anaesthetized with spontaneous breathing; and anaesthetized with positive-pressure ventilation. We analyzed the sensitivity, specificity, coherence and time relationship between the signals. RESULTS PPGr sensitivity for breath detection was [mean (SD)] >86(21)% and specificity >96(12)%. Respiratory detection in the macrocirculation (CVP, PVP and ABP) showed a sensitivity >83(29)% and specificity >93(12)%. The coherence between signals was high (0.75-0.99). The three measurement situations did not significantly influence sensitivity, specificity or time shifts between the PPGr, PVP, ABP, and the reference CVP signal despite changes in physiological data between measurements. CONCLUSION A respiratory synchronous variation in PPG and all invasive pressure signals was detected. The reflection mode PPGr signal seemed to be a constant phenomenon related to respiration regardless of whether or not the subject was awake, anaesthetized or ventilated, which increases its clinical usefulness in respiratory monitoring.
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Affiliation(s)
- L Nilsson
- Department of Anaesthesiology and Intensive Care, Linköping University Hospital, Linköping, Sweden.
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Abstract
Photoplethysmography (PPG) has been used in oxygen saturation measurement, heart rate monitoring, and the assessment of peripheral circulation and large artery compliance. However, the waveform of the photoplethysmographic signal may be affected by the contacting force between the sensor and the measurement site. The aim of this study is to investigate the change in pulse amplitude (AC), DC amplitude, ratio of AC/DC and normalized pulse area of the reflective photoplethysmographic signals with increasing contacting force, from 0.2 N to 1.8 N. Signals were recorded from the fingers of fifteen healthy subjects. With increasing contacting force, the DC amplitude increased and the normalized pulse area decreased, whereas the pulse amplitude and the ratio of AC/DC increased first and then decreased. For different subjects, the pulse amplitude and the ratio of AC/DC peaked at different contacting forces, from 0.2 N to 1.0 N, and most of the subjects achieved their maximum pulse amplitude within 0.2-0.4 N. Over the range of contacting force between 0.2 N and 0.8 N, the DC amplitude and the normalized pulse area had significant changes (p < 0.001). The results suggest that the effects of contacting force should be carefully examined in the design of photoplethysmography-based health care devices.
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Affiliation(s)
- X F Teng
- Joint Research Center for Biomedical Engineering, Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, NT, Hong Kong
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Nilsson L, Johansson A, Kalman S. Macrocirculation is not the sole determinant of respiratory induced variations in the reflection mode photoplethysmographic signal. Physiol Meas 2003; 24:925-37. [PMID: 14658783 DOI: 10.1088/0967-3334/24/4/009] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Photoplethysmography (PPG) is a non-invasive optical technique sensitive to variations in blood volume and perfusion in the tissue. Reflection mode PPG may have clinical advantages over transmission mode PPG. To improve clinical usefulness and further development of the reflection mode PPG, studies on factors that modify the signal are warranted. We studied the coherence between the respiratory induced intensity variations (RIIV) of the PPG signal and respiratory synchronous pressure variations in central venous pressure (CVP), peripheral venous pressure (PVP) and arterial blood pressure (ABP) during positive pressure ventilation on 12 patients under anaesthesia and on 12 patients with spontaneous breathing. During positive pressure ventilation the coherence between all signals was high. Inspiration was followed first by an increase in CVP, then by increases in ABP and PVP and lastly by RIIV indicating less back-scattered light. In spontaneously breathing patients the coherence was high, but the phases between the signals were changed. During inspiration, ABP decreased slightly before CVP, followed by a decrease in RIIV and PVP. The phase relation between RIIV and respiratory induced variation in macrocirculation changed with ventilatory mode, but not in a uniform way, indicating the influence of mechanisms other than macrocirculation involved in generating the RIIV signal.
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Affiliation(s)
- L Nilsson
- Department of Anaesthesiology and Intensive Care, Linköping University Hospital, Linköping, Sweden.
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