Noninvasive Cardiac Output Estimation Using a Novel
Photoplethysmogram Index
31st Annual International Conference of the IEEE EMBS Minneapolis, Minnesota, USA, September 2-6, 2009
IRJET- Segmentation of PCG Signal: A SurveyIRJET Journal
This document summarizes previous work on segmentation of phonocardiogram (PCG) signals. It discusses how PCG signals provide vital diagnostic information for detecting heart valve abnormalities and are becoming a common alternative to electrocardiogram signals. The document reviews different techniques used for feature extraction of PCG signals, including discrete wavelet transform and Fourier transforms. It also discusses using adaptive neuro fuzzy inference systems for classification of PCG signals. One study analyzed denoising PCG signals contaminated with white noise using discrete wavelet transform with different wavelets and decomposition levels. The document concludes that discrete wavelet transform is effective for feature extraction of PCG signals prior to classification.
Problems in Getting Ambulatory Blood Pressure Monitoring using Infrared PPGIJSRD
In the current study, a non-invasive technique for blood pressure (BP) measurement based on the detection of Photoplethysmographic (PPG) pulses during pressure-cuff deflation was compared to sphygmomanometryâ€â€the Korotkoff sounds technique. The PPG Senor used to measure blood pressure using the technique of correlation of volume and pressure. The performance of portable and wearable biosensorsis highly influenced by motion artifact, artery stiffness, measurement sites, light wavelength, sensor pressure, A novel real time system is proposed for accurate motion-tolerant extraction of heart rate (HR) and pulse oximeter oxygen saturation (SpO2) from wearable Photoplethysmographic (PPG) biosensors. Recently, monitoring of blood pressure fluctuation in the daily life is focused on in the hypertension care area to predict the risk of cardiovascular and cerebrovascular disease events. The main problem is using with digital BP monitoring machine is Doctors are not believe on digital machines they believe with only sphygmomanometer. In this paper, in order to propose an alternative system to the existed ambulatory blood pressure monitoring (ABPM) sphygmomanometer, to sort out the problems using small wearable device consisting of photoplethysmograph (PPG) sensors. Recent advances in optical technology have facilitated the use of high-intensity green LEDs for PPG, increasing the adoption of this measurement technique. In this paper, we briefly present the problems of PPG sensor and recent developments in wearable pulse rate sensors with green LEDs.
Photoplethysmographic assessment of pulse wave reflection: Blunted response to mellitus -adrenergic vasodilation in type II diabetes 2
endothelium-dependent beta
Extraction of respiratory rate from ppg signals using pca and emdeSAT Publishing House
This document discusses extracting respiratory rate from photoplethysmography (PPG) signals using principal component analysis (PCA) and empirical mode decomposition (EMD). It begins with an introduction to PPG signals and how they contain respiratory information. It then discusses previous efforts to extract respiratory signals from PPG that used methods like filtering and wavelets. The document proposes using PCA and EMD to improve upon existing methods. It provides background on PCA, EMD, and reviews literature on extracting respiratory information from ECG and how respiration modulates PPG signals. The aim is to evaluate different signal processing techniques to extract respiratory information from commonly available biomedical signals like ECG and PPG to avoid using additional sensors.
Extraction of respiratory rate from ppg signals using pca and emdeSAT Journals
Abstract Photoplethysmography is a non-invasive electro-optic method developed by Hertzman, which provides information on the blood volume flowing at a particular test site on the body close to the skin. PPG waveform contains two components; one, attributable to the pulsatile component in the vessels, i.e. the arterial pulse, which is caused by the heartbeat, and gives a rapidly alternating signal (AC component). The second one is due to the blood volume and its change in the skin which gives a steady signal that changes very slowly (DC component). PPG signal consists of not only the heart-beat information but also a respiratory signal. Estimation of respiration rates from Photoplethysmographic (PPG) signals would be an alternative approach for obtaining respiration related information.. There have been several efforts on PPG Derived Respiration (PDR), these methods are based on different signal processing techniques like filtering, wavelets and other statistical methods, which work by extraction of respiratory trend embedded into various physiological signals. PCA identifies patterns in data, and expresses the data in such a way as to highlight their similarities and differences. Since patterns in data can be hard to find in data of high dimension, where the luxury of graphical representation is not available, PCA is a powerful tool for analyzing such data. Due to external stimuli, biomedical signals are in general non-linear and non-stationary. Empirical Mode Decomposition is ideally suited to extract essential components which are characteristic of the underlying biological or physiological processes. The basis functions, called Intrinsic Mode Functions (IMFs) represent a complete set of locally orthogonal basis functions whose amplitude and frequency may vary over time. The contribution reviews the technique of EMD and related algorithms and discusses illustrative applications. Test results on PPG signals of the well known MIMIC database from Physiobank archive reveal that the proposed EMD method has efficiently extracted respiratory information from PPG signals. The evaluated similarity parameters in both time and frequency domains for original and estimated respiratory rates have shown the superiority of the method. Index Terms: Respiratory signal, PPG signal, Principal Component Analysis, EMD, ECG
This document discusses end tidal carbon dioxide (EtCO2) monitoring for patients with neuromuscular diseases. It provides information on the benefits of CO2 monitoring, the basics of how CO2 monitoring works, different CO2 monitoring devices and their costs, studies that have evaluated the accuracy and clinical applications of CO2 monitoring in various patient populations and clinical settings, and indications that CO2 monitoring can improve outcomes for patients with respiratory conditions.
AUTOMATIC HOME-BASED SCREENING OF OBSTRUCTIVE SLEEP APNEA USING SINGLE CHANNE...ijaia
Obstructive sleep apnea (OSA) is one of the most widespread respiratory diseases today. Complete or relative breathing cessations due to upper airway subsidence during sleep is OSA. It has confirmed potential influence on Covid-19 hospitalization and mortality, and is strongly associated with major comorbidities of severe Covid-19 infection. Un-diagnosed OSA may also lead to a variety of severe physical and mental side-effects. To score OSA severity, nocturnal sleep monitoring is performed under defined protocols and standards called polysomnography (PSG). This method is time-consuming, expensive, and requiring professional sleep technicians. Automatic home-based detection of OSA is welcome and in great demand. It is a fast and effective way for referring OSA suspects to sleep clinics for further monitoring. On-line OSA detection also can be a part of a closed-loop automatic control of the OSA therapeutic/assistive devices. In this paper, several solutions for online OSA detection are introduced and tested on 155 subjects of three different databases. The best combinational solution uses mutual information (MI) analysis for selecting out of ECG and SpO2-based features. Several methods of supervised and unsupervised machine learning are employed to detect apnoeic episodes. To achieve the best performance, the most successful classifiers in four different ternary combination methods are used. The proposed configurations exploit limited use of biological signals, have online working scheme, and exhibit uniform and acceptable performance (over 85%) in all the employed databases. The benefits have not been gathered all together in the previous published methods.
IRJET- Segmentation of PCG Signal: A SurveyIRJET Journal
This document summarizes previous work on segmentation of phonocardiogram (PCG) signals. It discusses how PCG signals provide vital diagnostic information for detecting heart valve abnormalities and are becoming a common alternative to electrocardiogram signals. The document reviews different techniques used for feature extraction of PCG signals, including discrete wavelet transform and Fourier transforms. It also discusses using adaptive neuro fuzzy inference systems for classification of PCG signals. One study analyzed denoising PCG signals contaminated with white noise using discrete wavelet transform with different wavelets and decomposition levels. The document concludes that discrete wavelet transform is effective for feature extraction of PCG signals prior to classification.
Problems in Getting Ambulatory Blood Pressure Monitoring using Infrared PPGIJSRD
In the current study, a non-invasive technique for blood pressure (BP) measurement based on the detection of Photoplethysmographic (PPG) pulses during pressure-cuff deflation was compared to sphygmomanometryâ€â€the Korotkoff sounds technique. The PPG Senor used to measure blood pressure using the technique of correlation of volume and pressure. The performance of portable and wearable biosensorsis highly influenced by motion artifact, artery stiffness, measurement sites, light wavelength, sensor pressure, A novel real time system is proposed for accurate motion-tolerant extraction of heart rate (HR) and pulse oximeter oxygen saturation (SpO2) from wearable Photoplethysmographic (PPG) biosensors. Recently, monitoring of blood pressure fluctuation in the daily life is focused on in the hypertension care area to predict the risk of cardiovascular and cerebrovascular disease events. The main problem is using with digital BP monitoring machine is Doctors are not believe on digital machines they believe with only sphygmomanometer. In this paper, in order to propose an alternative system to the existed ambulatory blood pressure monitoring (ABPM) sphygmomanometer, to sort out the problems using small wearable device consisting of photoplethysmograph (PPG) sensors. Recent advances in optical technology have facilitated the use of high-intensity green LEDs for PPG, increasing the adoption of this measurement technique. In this paper, we briefly present the problems of PPG sensor and recent developments in wearable pulse rate sensors with green LEDs.
Photoplethysmographic assessment of pulse wave reflection: Blunted response to mellitus -adrenergic vasodilation in type II diabetes 2
endothelium-dependent beta
Extraction of respiratory rate from ppg signals using pca and emdeSAT Publishing House
This document discusses extracting respiratory rate from photoplethysmography (PPG) signals using principal component analysis (PCA) and empirical mode decomposition (EMD). It begins with an introduction to PPG signals and how they contain respiratory information. It then discusses previous efforts to extract respiratory signals from PPG that used methods like filtering and wavelets. The document proposes using PCA and EMD to improve upon existing methods. It provides background on PCA, EMD, and reviews literature on extracting respiratory information from ECG and how respiration modulates PPG signals. The aim is to evaluate different signal processing techniques to extract respiratory information from commonly available biomedical signals like ECG and PPG to avoid using additional sensors.
Extraction of respiratory rate from ppg signals using pca and emdeSAT Journals
Abstract Photoplethysmography is a non-invasive electro-optic method developed by Hertzman, which provides information on the blood volume flowing at a particular test site on the body close to the skin. PPG waveform contains two components; one, attributable to the pulsatile component in the vessels, i.e. the arterial pulse, which is caused by the heartbeat, and gives a rapidly alternating signal (AC component). The second one is due to the blood volume and its change in the skin which gives a steady signal that changes very slowly (DC component). PPG signal consists of not only the heart-beat information but also a respiratory signal. Estimation of respiration rates from Photoplethysmographic (PPG) signals would be an alternative approach for obtaining respiration related information.. There have been several efforts on PPG Derived Respiration (PDR), these methods are based on different signal processing techniques like filtering, wavelets and other statistical methods, which work by extraction of respiratory trend embedded into various physiological signals. PCA identifies patterns in data, and expresses the data in such a way as to highlight their similarities and differences. Since patterns in data can be hard to find in data of high dimension, where the luxury of graphical representation is not available, PCA is a powerful tool for analyzing such data. Due to external stimuli, biomedical signals are in general non-linear and non-stationary. Empirical Mode Decomposition is ideally suited to extract essential components which are characteristic of the underlying biological or physiological processes. The basis functions, called Intrinsic Mode Functions (IMFs) represent a complete set of locally orthogonal basis functions whose amplitude and frequency may vary over time. The contribution reviews the technique of EMD and related algorithms and discusses illustrative applications. Test results on PPG signals of the well known MIMIC database from Physiobank archive reveal that the proposed EMD method has efficiently extracted respiratory information from PPG signals. The evaluated similarity parameters in both time and frequency domains for original and estimated respiratory rates have shown the superiority of the method. Index Terms: Respiratory signal, PPG signal, Principal Component Analysis, EMD, ECG
This document discusses end tidal carbon dioxide (EtCO2) monitoring for patients with neuromuscular diseases. It provides information on the benefits of CO2 monitoring, the basics of how CO2 monitoring works, different CO2 monitoring devices and their costs, studies that have evaluated the accuracy and clinical applications of CO2 monitoring in various patient populations and clinical settings, and indications that CO2 monitoring can improve outcomes for patients with respiratory conditions.
AUTOMATIC HOME-BASED SCREENING OF OBSTRUCTIVE SLEEP APNEA USING SINGLE CHANNE...ijaia
Obstructive sleep apnea (OSA) is one of the most widespread respiratory diseases today. Complete or relative breathing cessations due to upper airway subsidence during sleep is OSA. It has confirmed potential influence on Covid-19 hospitalization and mortality, and is strongly associated with major comorbidities of severe Covid-19 infection. Un-diagnosed OSA may also lead to a variety of severe physical and mental side-effects. To score OSA severity, nocturnal sleep monitoring is performed under defined protocols and standards called polysomnography (PSG). This method is time-consuming, expensive, and requiring professional sleep technicians. Automatic home-based detection of OSA is welcome and in great demand. It is a fast and effective way for referring OSA suspects to sleep clinics for further monitoring. On-line OSA detection also can be a part of a closed-loop automatic control of the OSA therapeutic/assistive devices. In this paper, several solutions for online OSA detection are introduced and tested on 155 subjects of three different databases. The best combinational solution uses mutual information (MI) analysis for selecting out of ECG and SpO2-based features. Several methods of supervised and unsupervised machine learning are employed to detect apnoeic episodes. To achieve the best performance, the most successful classifiers in four different ternary combination methods are used. The proposed configurations exploit limited use of biological signals, have online working scheme, and exhibit uniform and acceptable performance (over 85%) in all the employed databases. The benefits have not been gathered all together in the previous published methods.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
IRJET - Sleep Apnea Detection using Physiological SignalsIRJET Journal
This document summarizes a research study on detecting sleep apnea using physiological signals. The study proposes detecting sleep apnea automatically using short-term event extraction from electrocardiography (ECG) signals combined with neural network methods. Currently, sleep apnea is diagnosed through overnight polysomnography testing in a sleep lab, which is costly and has limited availability. The proposed method uses ECG signals as input data, applies signal processing techniques like notch filtering and wavelet transformation to extract features, and then uses a neural network to classify whether sleep apnea is present or not. This automated approach could enable faster diagnosis and analysis of more patients compared to current polysomnography testing.
This document summarizes principles and techniques of intracranial pressure (ICP) measurement and waveform interpretation. It discusses the history of ICP monitoring, indications for monitoring, invasive and non-invasive monitoring techniques, optimal sensor locations, ICP waveform analysis in both time and frequency domains, and guidelines for ICP monitoring in traumatic brain injury. The key points covered include different invasive sensor types, complications of external ventricular drainage, interpreting mean ICP and waveform trends, and using indices like pressure reactivity and variability for management.
Noninvasive blood glucose monitoring system based on near-infrared method IJECEIAES
This document summarizes a study that developed a non-invasive blood glucose monitoring system using near-infrared spectroscopy. The system uses a finger sensor with an LED light source to collect photoplethysmography signals from the finger, which are preprocessed with an analog circuit and filtered with a Butterworth filter. A linear regression model is used to correlate the photoplethysmography peak data to blood glucose concentration measurements, developing individual calibration models for each of the 10 subjects. Experimental results found a root mean square error of 8.264-13.166 mg/dL between predicted and measured glucose values, with an R-squared value of 0.839, demonstrating clinically acceptable prediction in the standard error grid.
Design and development of electro optical system for acquisition of ppg signa...eSAT Publishing House
This document describes the design and development of an electro-optical photoplethysmography (PPG) system for acquiring PPG signals to assess the cardiovascular system. The system uses a light emitting diode and photodetector in a finger probe to non-invasively measure blood volume changes with each heartbeat. The acquired PPG signals are digitized and wirelessly transmitted using ZigBee technology. Preliminary testing on normal subjects found the pulse rates measured by the developed system to be accurate and in good agreement with a standard pulse oximeter system. The wireless PPG system allows for remote monitoring of cardiovascular parameters and has potential applications in ambulatory monitoring and postoperative care.
This document provides an overview of wearable photoplethysmographic sensors. It discusses how PPG sensors use light-emitting diodes and photodetectors to noninvasively monitor pulse rate through optical detection of blood volume changes. Recent advances have enabled the use of high-intensity green LEDs for PPG. The document reviews the history of PPG and developments in wearable pulse rate sensors. Examples of wearable PPG devices include earbud, ring, wristwatch, and forehead sensors. PPG offers a simple, reliable, and low-cost means of monitoring pulse rate.
This document discusses monitoring in anesthesia. It begins by outlining the importance of monitoring anesthetized patients to evaluate their oxygenation, ventilation, circulation and temperature continuously. It then discusses the basic monitoring parameters including ECG, blood pressure, end-tidal carbon dioxide (EtCO2) and pulse oximetry. The document focuses on the principles and uses of pulse oximetry and capnography, which are important non-invasive tools for monitoring oxygenation and ventilation during anesthesia.
This document proposes a policy-based runtime verification framework for hypertension monitoring using electrocardiogram (ECG) sensing. Key aspects include:
1) A decision tree model is implemented using timed ECG features to extract patterns/policies related to hypertension.
2) The extracted ECG policies are formally specified as timed automata to synthesize a runtime verification monitor.
3) The monitor continuously verifies the ECG policies and provides a verdict on whether hypertension is present or not based on ECG events.
The framework aims to provide explainable, non-invasive hypertension monitoring using a formal methods-based approach.
This document provides a consensus from 16 experts on updates to hemodynamic monitoring. It briefly reviews various hemodynamic monitoring systems and their advantages and limitations. The key points are:
1. Hemodynamic monitoring plays an important role in managing critically ill patients by helping identify underlying issues and guide appropriate therapy.
2. The pulmonary artery catheter (PAC) has long been considered the gold standard but is invasive; less invasive alternatives have emerged but accuracy varies compared to PAC.
3. The document aims to provide clarity on monitoring options rather than endorse any single system, and proposes ten principles to guide clinical choice of monitoring.
1) Standard monitoring during anesthesia includes continuous evaluation of oxygenation, ventilation, circulation, and temperature.
2) Advanced monitoring includes respiratory monitoring using precordial and esophageal stethoscopes, pulse oximetry, capnography, and anesthetic gas analysis.
3) Central venous catheterization is used for monitoring central venous pressure, fluid administration, infusion of caustic drugs, and venous access in patients with poor peripheral veins. Complications include infection, arrhythmia, and puncture of other vessels.
Researchers developed a non-invasive technique to diagnose and classify chronic obstructive pulmonary disease (COPD) using electromyography (EMG) signals from the sternomastoid muscle during respiration. They analyzed EMG signals in the time, frequency, and time-frequency domains, and developed an onset detection algorithm and conduction velocity measure that improved COPD detection accuracy to 98.61%. Researchers also used continuous wavelet transform analysis at specific frequencies to extract features and classify COPD severity with 85.89% accuracy. This technique provides an easy-to-use alternative to spirometry for COPD diagnosis and assessment.
The document discusses fibre optic sensors for measuring pH. It describes how fibre optic sensors work by modulating light properties like intensity, phase or wavelength. They have advantages for biomedical applications like in vivo monitoring. An ideal fibre optic sensor for biomedicine would be reliable, easy for operators to use, and low cost. The document discusses measuring blood pH, gastric/esophageal pH, and tissue pH using fibre optic sensors. It describes different sensor designs and challenges like sensitivity to light propagation. Fibre optic sensors eliminate drawbacks of traditional glass pH electrodes.
This document describes a study on using RF spectroscopy to measure blood glucose levels. Researchers designed a rectangular measurement cell and used a tracking generator and signal analyzer to collect RF response data from glucose solutions of varying concentrations between 10MHz-4GHz. The results showed variations in absorption levels that correlated with glucose concentration at certain frequencies. The goal is to develop a non-invasive, portable device for glucose monitoring by feeding the RF spectral data into a multivariate analysis model programmed on an FPGA.
This document describes a study on using radio frequency (RF) spectroscopy to measure blood glucose levels. Researchers designed a measurement cell to collect RF responses from samples of varying glucose concentrations dissolved in water, simulating levels found in human blood. RF signals were injected into the cell and analyzed between 10MHz-4GHz. Response graphs showed absorption decreasing with higher glucose concentrations. The document proposes developing a non-invasive device using these RF measurements, multivariate analysis, and partial least squares regression to estimate blood glucose and other constituent levels from RF spectra without drawing blood. This could provide a low-cost way to regularly monitor important health parameters.
This document proposes a low-cost wireless spectrum-capnography system to detect cholesterol levels in blood using breath analysis. It would measure concentrations of isoprene and carbon dioxide (CO2), which are related to cholesterol biosynthesis. A spectrophotometer would detect isoprene concentration and a capnometer would detect CO2 concentration. These values could then indicate cholesterol levels in the blood. The system would also record electrocardiogram (ECG) signals to provide additional cardiovascular information. It would use ZigBee technology to transmit data to a mobile device for display. Simulation results showed the system could distinguish venous and arterial CO2 concentrations related to cholesterol levels.
This document discusses the value of continuous cardiac output (CO) monitoring over intermittent CO monitoring. It notes that continuous CO monitoring is better for assessing responses to short-term therapeutic interventions and identifying low or high CO values not evident clinically. While new CO monitoring devices show similar mean values to pulmonary artery catheters, they often trend differently in response to therapy. Continuous monitoring of other parameters like urinary output, blood glucose and lactate can also provide useful insights. Overall, maximizing information from real-time continuous physiological monitoring should be recognized as important as physical examination in medicine.
This document provides an overview of various methods for respiratory monitoring. It discusses physical examination, pulse oximetry, mixed venous oxygen saturation, tissue oxygenation, capnography and blood gas analysis, respiratory mechanics, respiratory rate monitoring, and imaging techniques. Pulse oximetry measures arterial oxygen saturation noninvasively using light absorption. Mixed venous oxygen saturation reflects whole body oxygen uptake. Tissue oxygenation can be assessed using near-infrared or visible light spectroscopy. Capnography monitors exhaled carbon dioxide to evaluate ventilation and cardiac output.
This document discusses pulse oximetry and pulse oximeter design. It explains the working principles of transmittance and reflectance pulse oximeters, how they calculate oxygen saturation levels, and potential sources of error. Key points covered include the use of red and infrared light to measure oxygenated and deoxygenated hemoglobin, Beer's and Lambert's laws regarding light absorption, and the signal processing and calibration methods used to determine oxygen saturation values. Design considerations for pulse oximeter sensors, testing parameters, and general software models are also summarized.
1. Basic monitoring standards established by anesthesia societies require monitoring of circulation, ventilation, and oxygenation including ECG, blood pressure, capnography, and pulse oximetry.
2. Pulse oximetry uses light absorption to measure oxygen saturation and heart rate while capnography monitors expired carbon dioxide.
3. Invasive arterial blood pressure monitoring provides direct measurement but risks include hematoma and nerve damage.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
IRJET - Sleep Apnea Detection using Physiological SignalsIRJET Journal
This document summarizes a research study on detecting sleep apnea using physiological signals. The study proposes detecting sleep apnea automatically using short-term event extraction from electrocardiography (ECG) signals combined with neural network methods. Currently, sleep apnea is diagnosed through overnight polysomnography testing in a sleep lab, which is costly and has limited availability. The proposed method uses ECG signals as input data, applies signal processing techniques like notch filtering and wavelet transformation to extract features, and then uses a neural network to classify whether sleep apnea is present or not. This automated approach could enable faster diagnosis and analysis of more patients compared to current polysomnography testing.
This document summarizes principles and techniques of intracranial pressure (ICP) measurement and waveform interpretation. It discusses the history of ICP monitoring, indications for monitoring, invasive and non-invasive monitoring techniques, optimal sensor locations, ICP waveform analysis in both time and frequency domains, and guidelines for ICP monitoring in traumatic brain injury. The key points covered include different invasive sensor types, complications of external ventricular drainage, interpreting mean ICP and waveform trends, and using indices like pressure reactivity and variability for management.
Noninvasive blood glucose monitoring system based on near-infrared method IJECEIAES
This document summarizes a study that developed a non-invasive blood glucose monitoring system using near-infrared spectroscopy. The system uses a finger sensor with an LED light source to collect photoplethysmography signals from the finger, which are preprocessed with an analog circuit and filtered with a Butterworth filter. A linear regression model is used to correlate the photoplethysmography peak data to blood glucose concentration measurements, developing individual calibration models for each of the 10 subjects. Experimental results found a root mean square error of 8.264-13.166 mg/dL between predicted and measured glucose values, with an R-squared value of 0.839, demonstrating clinically acceptable prediction in the standard error grid.
Design and development of electro optical system for acquisition of ppg signa...eSAT Publishing House
This document describes the design and development of an electro-optical photoplethysmography (PPG) system for acquiring PPG signals to assess the cardiovascular system. The system uses a light emitting diode and photodetector in a finger probe to non-invasively measure blood volume changes with each heartbeat. The acquired PPG signals are digitized and wirelessly transmitted using ZigBee technology. Preliminary testing on normal subjects found the pulse rates measured by the developed system to be accurate and in good agreement with a standard pulse oximeter system. The wireless PPG system allows for remote monitoring of cardiovascular parameters and has potential applications in ambulatory monitoring and postoperative care.
This document provides an overview of wearable photoplethysmographic sensors. It discusses how PPG sensors use light-emitting diodes and photodetectors to noninvasively monitor pulse rate through optical detection of blood volume changes. Recent advances have enabled the use of high-intensity green LEDs for PPG. The document reviews the history of PPG and developments in wearable pulse rate sensors. Examples of wearable PPG devices include earbud, ring, wristwatch, and forehead sensors. PPG offers a simple, reliable, and low-cost means of monitoring pulse rate.
This document discusses monitoring in anesthesia. It begins by outlining the importance of monitoring anesthetized patients to evaluate their oxygenation, ventilation, circulation and temperature continuously. It then discusses the basic monitoring parameters including ECG, blood pressure, end-tidal carbon dioxide (EtCO2) and pulse oximetry. The document focuses on the principles and uses of pulse oximetry and capnography, which are important non-invasive tools for monitoring oxygenation and ventilation during anesthesia.
This document proposes a policy-based runtime verification framework for hypertension monitoring using electrocardiogram (ECG) sensing. Key aspects include:
1) A decision tree model is implemented using timed ECG features to extract patterns/policies related to hypertension.
2) The extracted ECG policies are formally specified as timed automata to synthesize a runtime verification monitor.
3) The monitor continuously verifies the ECG policies and provides a verdict on whether hypertension is present or not based on ECG events.
The framework aims to provide explainable, non-invasive hypertension monitoring using a formal methods-based approach.
This document provides a consensus from 16 experts on updates to hemodynamic monitoring. It briefly reviews various hemodynamic monitoring systems and their advantages and limitations. The key points are:
1. Hemodynamic monitoring plays an important role in managing critically ill patients by helping identify underlying issues and guide appropriate therapy.
2. The pulmonary artery catheter (PAC) has long been considered the gold standard but is invasive; less invasive alternatives have emerged but accuracy varies compared to PAC.
3. The document aims to provide clarity on monitoring options rather than endorse any single system, and proposes ten principles to guide clinical choice of monitoring.
1) Standard monitoring during anesthesia includes continuous evaluation of oxygenation, ventilation, circulation, and temperature.
2) Advanced monitoring includes respiratory monitoring using precordial and esophageal stethoscopes, pulse oximetry, capnography, and anesthetic gas analysis.
3) Central venous catheterization is used for monitoring central venous pressure, fluid administration, infusion of caustic drugs, and venous access in patients with poor peripheral veins. Complications include infection, arrhythmia, and puncture of other vessels.
Researchers developed a non-invasive technique to diagnose and classify chronic obstructive pulmonary disease (COPD) using electromyography (EMG) signals from the sternomastoid muscle during respiration. They analyzed EMG signals in the time, frequency, and time-frequency domains, and developed an onset detection algorithm and conduction velocity measure that improved COPD detection accuracy to 98.61%. Researchers also used continuous wavelet transform analysis at specific frequencies to extract features and classify COPD severity with 85.89% accuracy. This technique provides an easy-to-use alternative to spirometry for COPD diagnosis and assessment.
The document discusses fibre optic sensors for measuring pH. It describes how fibre optic sensors work by modulating light properties like intensity, phase or wavelength. They have advantages for biomedical applications like in vivo monitoring. An ideal fibre optic sensor for biomedicine would be reliable, easy for operators to use, and low cost. The document discusses measuring blood pH, gastric/esophageal pH, and tissue pH using fibre optic sensors. It describes different sensor designs and challenges like sensitivity to light propagation. Fibre optic sensors eliminate drawbacks of traditional glass pH electrodes.
This document describes a study on using RF spectroscopy to measure blood glucose levels. Researchers designed a rectangular measurement cell and used a tracking generator and signal analyzer to collect RF response data from glucose solutions of varying concentrations between 10MHz-4GHz. The results showed variations in absorption levels that correlated with glucose concentration at certain frequencies. The goal is to develop a non-invasive, portable device for glucose monitoring by feeding the RF spectral data into a multivariate analysis model programmed on an FPGA.
This document describes a study on using radio frequency (RF) spectroscopy to measure blood glucose levels. Researchers designed a measurement cell to collect RF responses from samples of varying glucose concentrations dissolved in water, simulating levels found in human blood. RF signals were injected into the cell and analyzed between 10MHz-4GHz. Response graphs showed absorption decreasing with higher glucose concentrations. The document proposes developing a non-invasive device using these RF measurements, multivariate analysis, and partial least squares regression to estimate blood glucose and other constituent levels from RF spectra without drawing blood. This could provide a low-cost way to regularly monitor important health parameters.
This document proposes a low-cost wireless spectrum-capnography system to detect cholesterol levels in blood using breath analysis. It would measure concentrations of isoprene and carbon dioxide (CO2), which are related to cholesterol biosynthesis. A spectrophotometer would detect isoprene concentration and a capnometer would detect CO2 concentration. These values could then indicate cholesterol levels in the blood. The system would also record electrocardiogram (ECG) signals to provide additional cardiovascular information. It would use ZigBee technology to transmit data to a mobile device for display. Simulation results showed the system could distinguish venous and arterial CO2 concentrations related to cholesterol levels.
This document discusses the value of continuous cardiac output (CO) monitoring over intermittent CO monitoring. It notes that continuous CO monitoring is better for assessing responses to short-term therapeutic interventions and identifying low or high CO values not evident clinically. While new CO monitoring devices show similar mean values to pulmonary artery catheters, they often trend differently in response to therapy. Continuous monitoring of other parameters like urinary output, blood glucose and lactate can also provide useful insights. Overall, maximizing information from real-time continuous physiological monitoring should be recognized as important as physical examination in medicine.
This document provides an overview of various methods for respiratory monitoring. It discusses physical examination, pulse oximetry, mixed venous oxygen saturation, tissue oxygenation, capnography and blood gas analysis, respiratory mechanics, respiratory rate monitoring, and imaging techniques. Pulse oximetry measures arterial oxygen saturation noninvasively using light absorption. Mixed venous oxygen saturation reflects whole body oxygen uptake. Tissue oxygenation can be assessed using near-infrared or visible light spectroscopy. Capnography monitors exhaled carbon dioxide to evaluate ventilation and cardiac output.
This document discusses pulse oximetry and pulse oximeter design. It explains the working principles of transmittance and reflectance pulse oximeters, how they calculate oxygen saturation levels, and potential sources of error. Key points covered include the use of red and infrared light to measure oxygenated and deoxygenated hemoglobin, Beer's and Lambert's laws regarding light absorption, and the signal processing and calibration methods used to determine oxygen saturation values. Design considerations for pulse oximeter sensors, testing parameters, and general software models are also summarized.
1. Basic monitoring standards established by anesthesia societies require monitoring of circulation, ventilation, and oxygenation including ECG, blood pressure, capnography, and pulse oximetry.
2. Pulse oximetry uses light absorption to measure oxygen saturation and heart rate while capnography monitors expired carbon dioxide.
3. Invasive arterial blood pressure monitoring provides direct measurement but risks include hematoma and nerve damage.
This document describes several physiologic data collection products from LD Products including a galvanic skin response device, body composition analyzer, and photoelectrical plethysmography device. It also discusses software for data interpretation and management, as well as telemedicine services. The ES Complex combines multiple technologies into a single device for measuring parameters like heart rate, blood oxygen levels, pulse analysis, and body composition. It enables early diagnosis and management of conditions like metabolic syndrome, diabetes, and cardiovascular disease through non-invasive screening tests.
EIS technology : bioimpedance application in selective serotonin reuptakeES-Teck India
Through the 6 tactile electrodes, a weak DC current is sending alternatively between 2 electrodes with a sequence and the EIS-GS system is recording the electrical conductance of 11 pathways of the human body.
EIS Technology: bioimpedance chronoamperometry in adjunct to screen the prost...ES-Teck India
Through the 6 tactile electrodes, a weak DC current is sending alternatively between 2 electrodes with a sequence and the EIS system is recording the electrical conductance of 11 pathways of the human body.
Summary of clinical investigations es teck complex systemES-Teck India
Summary of the clinical investigations E.S.Teck Complex March, 20, 2010
Summary of Clinical Investigations ES Teck Complex system EIS System in adjunct to Treatments’ monitoring and to diagnosis with the conventional methods
The study analyzed arterial pulse recordings from 1,005 subjects aged 2-91 years using a new tonometry technique. Three main findings were observed with increasing age: (1) pulse amplitude increased in all artery sites, (2) diastolic decay steepened and diastolic waves diminished, (3) carotid pulses showed a merging of two systolic peaks. These changes reflect increased arterial stiffness and earlier wave reflections with age.
The document summarizes a research article that examines the relationship between parameters derived from the second derivative of finger photoplethysmogram (PPG) signals and pulse wave velocity (PWV), a measure of arterial stiffness. The study found low but significant correlations between the PPG parameters and PWV. While the measures provide related information on arterial properties, they are not equivalent since PWV reflects aortic stiffness passive effects on pressure, while PPG parameters depend on both central and peripheral effects including ventricular ejection. The relationship between PPG and PWV is complex due to different underlying mechanisms assessed and potential sources of error in the non-invasive techniques.
This document provides an overview of pulse oximetry and the oxyhemoglobin dissociation curve. It defines a pulse oximeter, describes how it works by measuring oxygenated and deoxygenated hemoglobin using light wavelengths, and notes that a normal oxygen saturation level is above 95%. The document also discusses the oxyhemoglobin dissociation curve and how shifts can occur, changing the relationship between oxygen in the blood and hemoglobin saturation. Common uses of pulse oximetry and potential limitations/interferences are outlined.
Comparison of Invasive vs Noninvasive Pulse Wave Indices in Detection of Signifi cant Coronary Artery Disease: Can We Use Noninvasive Pulse Wave Indices as Screening Test
1. Pulse wave analysis in historical times was an important part of medical examination but fell out of favor with the introduction of the cuff sphygmomanometer.
2. Modern pulse wave analysis is regaining favor as limitations of the cuff are recognized. Accurate recording and analysis of the arterial pulse is now possible through high-fidelity tonometry and understanding of arterial hemodynamics.
3. Analysis of pulse waveforms can provide clinically important information about ventricular-vascular interaction and disease states like hypertension that was previously only available through invasive methods.
Guidelines heart rate_variability_ft_1996[1]ES-Teck India
Guidelines
Heart rate variability
Standards of measurement, physiological interpretation, and
clinical use
Task Force of The European Society of Cardiology and The North American
Society of Pacing and Electrophysiology (Membership of the Task Force listed in
the Appendix)
Hypertension:Volume 32(2)August 1998pp 365-370
Assessment of Vasoactive Agents and Vascular Aging by the Second Derivative of
Photoplethysmogram Waveform
[Third Workshop On Structure And Function Of Large Arteries: Part Ii]
The document discusses pulse oximetry and oxygen saturation.
[1] A pulse oximeter uses light to determine the percentage of hemoglobin in blood that is saturated with oxygen (SpO2). It also measures pulse rate.
[2] Oxygen is brought into the lungs and transfers to blood in lung capillaries. It is transported throughout the body bound to hemoglobin in red blood cells.
[3] Oxygen saturation measured by a pulse oximeter (SpO2) indicates if sufficient oxygen is being supplied to tissues. Monitoring SpO2 can help assess disease severity and determine need for treatment.
Cerebral Perfusion Response
to Successful Treatment of
Depression With Different
Serotoninergic Agents with antidepressant therapy have been reported in a number of studies.2–4 In contrast, decreases in the ventral anterior cingulate blood flow were found in response to desipramine,5 electroshock therapy,6 and flu-7
This study examined the effects of intracisternally injected serotonin on cerebral blood flow and systemic pressure in cats during winter and summer months. The researchers found that serotonin produced decreases in cerebral blood flow and systemic pressure lasting 60 to 180 minutes after injection. The decreases in blood flow were significantly greater in winter than summer, but decreases in systemic pressure were not different between seasons. Cats exposed to 3 days of darkness before serotonin injection experienced greater decreases in blood flow compared to light-exposed cats, while systemic pressure changes were similar. The findings suggest the photoperiod may affect the sensitivity of cerebral vessels to serotonin in cats.
The role of antioxidant supplement in immune system, neoplastic, and neurodegenerative disorders: a point of view for an assessment
of the risk/benefit profile. Nutritional Journal
8 Surprising Reasons To Meditate 40 Minutes A Day That Can Change Your Life.pptxHolistified Wellness
We’re talking about Vedic Meditation, a form of meditation that has been around for at least 5,000 years. Back then, the people who lived in the Indus Valley, now known as India and Pakistan, practised meditation as a fundamental part of daily life. This knowledge that has given us yoga and Ayurveda, was known as Veda, hence the name Vedic. And though there are some written records, the practice has been passed down verbally from generation to generation.
Cell Therapy Expansion and Challenges in Autoimmune DiseaseHealth Advances
There is increasing confidence that cell therapies will soon play a role in the treatment of autoimmune disorders, but the extent of this impact remains to be seen. Early readouts on autologous CAR-Ts in lupus are encouraging, but manufacturing and cost limitations are likely to restrict access to highly refractory patients. Allogeneic CAR-Ts have the potential to broaden access to earlier lines of treatment due to their inherent cost benefits, however they will need to demonstrate comparable or improved efficacy to established modalities.
In addition to infrastructure and capacity constraints, CAR-Ts face a very different risk-benefit dynamic in autoimmune compared to oncology, highlighting the need for tolerable therapies with low adverse event risk. CAR-NK and Treg-based therapies are also being developed in certain autoimmune disorders and may demonstrate favorable safety profiles. Several novel non-cell therapies such as bispecific antibodies, nanobodies, and RNAi drugs, may also offer future alternative competitive solutions with variable value propositions.
Widespread adoption of cell therapies will not only require strong efficacy and safety data, but also adapted pricing and access strategies. At oncology-based price points, CAR-Ts are unlikely to achieve broad market access in autoimmune disorders, with eligible patient populations that are potentially orders of magnitude greater than the number of currently addressable cancer patients. Developers have made strides towards reducing cell therapy COGS while improving manufacturing efficiency, but payors will inevitably restrict access until more sustainable pricing is achieved.
Despite these headwinds, industry leaders and investors remain confident that cell therapies are poised to address significant unmet need in patients suffering from autoimmune disorders. However, the extent of this impact on the treatment landscape remains to be seen, as the industry rapidly approaches an inflection point.
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Dive into an in-depth exploration of the histological structure of female reproductive system with this comprehensive lecture. Presented by Dr. Ayesha Irfan, Assistant Professor of Anatomy, this presentation covers the Gross anatomy and functional histology of the female reproductive organs. Ideal for students, educators, and anyone interested in medical science, this lecture provides clear explanations, detailed diagrams, and valuable insights into female reproductive system. Enhance your knowledge and understanding of this essential aspect of human biology.
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Osteoporosis is an increasing cause of morbidity among the elderly.
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2. obtained [6]. invasive arterial catheter or a bedside Finapres device for
In this paper, we propose a novel indicator of CO, the acquiring the continuous blood pressure measurement.
inflection and harmonic area ratio (IHAR), which is derived
from PPG signals. The ability of IHAR to trace CO changes PPG
was evaluated in a bicycle exercise experiment. Time domain Frequency domain
ABP FFT(f1)
magnitude
FFT(f2)
S1 S2
CO AC TPR
f1 f2 … … fn Hz
frequency
(a) (b)
Fig. 2. (a) is PPG wave in the time domain. S1 and S2 are the areas
under the whole PPG wave and the part of wave after the point of
Fig. 1. Two-element Windkessel model. inflection, respectively. IPA=S2/S1. (b) is PPG wave in the frequency
domain. FFT ( f n ) is the magnitude at the nth harmonic. NHA =
N N
II. METHODOLOGY ∑ FFT ( f ) ∑ FFT ( f ).
n =2
2
n
n =1
2
n
According to the two-element Windkessel model shown However, as shown in equation (1), blood pressure
in Fig. 1, CO could be calculated from the analysis of measurement is not a necessity for obtaining CO, if proper
continuous arterial blood pressure waveform by a so called surrogates of MBP and TPR can be derived from other
pulse contour method. In this model, the cardiovascular signals. According to wave reflection theory, arterial blood
system is analogous to a current source connected with a pulse could be divided into two waves: a first wave
two-element circuit. CO, which is mimicked by the mean produced by heart pumping and a second wave produced by
amount of current passing through the TPR (total peripheral pulse wave reflection. Therefore, the inflection point area
resistance), equals the mean pressure (mean arterial blood ratio (IPA), the area ratio of the second and first peak in the
pressure, MBP) divided by the TPR: PPG wave (see Fig. 2 (a)), is mainly influenced by the
CO = MBP TPR (1). strength of pulse wave reflection. Pulse wave reflection
In this method, if a continuous arterial pressure waveform is results from the impedance mismatch between different parts
obtained, MBP could be calculated beat to beat. TPR is in the arterial system, e.g., the compliance and resistance
firstly initialized by a pair of calibration CO and MBP data, mismatches between the big, elastic arteries and the small
and its value of the current beat is calculated from MBP and arteries. Studies have shown that approximate 90% of the
estimated CO of the previous beat, iteratively. The main TPR is located in the small arteries. Hence, if the small
shortcoming of such technique is that it needs either an arteries contract, the TPR will change, which will change the
5-min. 5-min. 60W 5-min. 60W 5-min. 60W
rest bicycle exercise bicycle exercise bicycle exercise
…… ……
…… ……
1 2 3 4 5 6 7 8 9 10 11 17 18 19 25
3-min. 6-min. 6-min. 6-min.
Resting Post-exercise 1 Post-exercise 2 Post-exercise 3
represented BP measurement by a registered nurse
numbers 1-25 indicate the datasets of simultaneous measurements of CO and PPG
Fig. 3. Experiment procedure.
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3. impedance mismatch, influence the strength of the wave IV. DATA ANALYSIS
reflection, and further change IPA. In our previous For each subject, 25 datasets were obtained, including 1
investigation [5], IPA has shown to be a very good indicator dataset at rest and 8 datasets in each post exercise phase (see
of TPR when it changes after exercise. The pulse wave Fig. 3). The 8 datasets after each exercise were obtained
reflection not only changes the shape of the PPG signal in from the 6-min continuous data divided by the intermittent
the time domain, but also in the frequency domain. Our BP measurements. As shown in Fig. 3, BP was also
previous study [7] has proved that the normalized harmonic measured by a nurse every other dataset, e.g., during datasets
area (NHA), a parameter derived from frequency domain 2, 4, 6, 8 for post exercise phase 1.
analysis (see Fig. 2 (b)), is related to pulse wave reflection For offline analysis, each dataset of PPG signals was re-
and is strongly correlated with systolic and diastolic blood sampled to 100 Hz and divided into beat-to-beat waves. The
pressure. Therefore, IHAR, defined as NHA divided by IPA, start point of each beat is defined as the beginning of its
is proposed as a potential CO indicator and expressed as systolic rise, which is also the end of the diastolic fall wave
follows: of the previous beat. Single PPG wave was transferred to the
⎛ N
⎞ frequency domain by 512 points FFT (ensuring a resolution
⎜ ∑ FFT 2 ( f n ) ⎟
⎜1 − n=2 ⎟ of more than 10 points per Hz). Then, beat-to-beat IHAR
⎜ N ⎟ was calculated using equation (2). Meanwhile, COimp was
⎜ ∑ FFT ( f n ) ⎟
2
obtained by the impedance cardiograph device, beat by beat.
IHAR = ⎝ n=1 ⎠ (2), “Beat by beat” here meant that COimp was acquired and
⎛ S2 ⎞ saved in a “beat to beat” format, but was actually calculated
⎜ ⎟
⎜S ⎟
⎝ 1⎠ from the rolling average of eight impedance wave and five
where S1 and S2 are the areas under the whole PPG wave and ECG wave in the algorithm. As a result, it was impossible in
the part of wave after the point of inflection in the time this study to compare IHAR with COimp in a beat-to-beat
domain, respectively (see Fig. 2(a)), and FFT 2 ( f n ) is the way, but only to compare the means of each dataset. For CO
estimation, all datasets of IHAR and COimp were firstly used
square of the magnitude at the nth harmonic of the PPG wave to produce CO = α ⋅ IHAR + β by the least squares linear
in the frequency domain (see Fig. 2(b)).
regression method, and then, the COIHAR results were
The performance of IHAR for CO estimation was
obtained from IHAR by the above equation.
evaluated in a bicycle exercise experiment. An impedance
cardiograph device, Physio Flow PF-05 (Manatec
V. RESULTS
Biomedical, Macheren, France), was used as the benchmark
of CO measurement. The validity of this device has been As shown in Table I, the hemodynamic parameters,
established in both normotensive adults and cardiovascular including heart rate, systolic blood pressure, diastolic blood
patients versus the direct Fick method (lab golden standard pressure and cardiac output, have significantly changed after
of CO measurement) both at rest and exercise conditions [2] each 5 min of bicycle exercise, compared with those
[8]. obtained at rest (p<0.05).
The intra-subject correlation coefficients (r) between
III. EXPERIMENT PROTOCOL IHAR and COimp are listed in Table II. For all subjects,
IHAR was positively correlated to COimp. Except for subject
16 normotensive volunteers (8 males and 8 females), aged
13 (p=0.054), there was a strong correlation between IHAR
from 22 to 34 years, participated in this study. Informed
and COimp in the other 15 subjects (mean r = 0.82, p<0.01).
consent was obtained from each participant. The
experimental procedures are depicted in Fig. 3. Upon arrival, TABLE I
CHANGES OF HEMODYNAMIC PARAMETERS AFTER 1 , 2 , AND 3RD
ST ND
subjects were asked to rest for 5 minutes. Then, the systolic
EXERCISE COMPARED WITH THOSE AT REST
blood pressure (SBP) and diastolic blood pressure (DBP)
1st 2nd 3rd
were measured from the left arm by a registered nurse. After At Rest
Exercise Exercise Exercise
this, PPG and cardiac output were recorded simultaneously Heart Rate
76±10 92±17﹡ 95±17﹡ 100±16﹡
for 1 min. Then, the subjects were asked to ride the bicycle (beat/s)
SBP (mmHg) 106±12 116±14﹡ 117±14﹡ 118±15﹡
(Corival V2, Lode VB, Groningen, Netherland) for 5
DBP (mmHg) 61±7 59±10﹡ 60±10﹡ 61±10﹡
minutes at 60 W. Immediately after exercise, 6-min of PPG CO (L/min) 6.3±1.2 8.5±1.8﹡ 8.7±1.9﹡ 9.2±2.0﹡
and CO data were continuously acquired, meanwhile, at time ﹡
significant difference with the results obtained at rest (p<0.01).
points after exercise of 0 min, 1.5 min, 3 min, 4.5 min and 6
min, blood pressure (BP) was measured. Then, the same 5
The dynamic range of CO estimated from IHAR (COIHAR)
min exercise and post-exercise data acquisition procedures
was very similar to that of COimp (COIHAR: 4.02 L/min-14.72
were repeated twice. PPG was recorded on the right index
L/min; and COimp: 3.66 L/min-14.48 L/min). As shown in
finger by an in-house designed acquisition system. CO was
Table II, the standard deviation (SD) of the estimation
measured by the Physio Flow PF-05 impedance cardiograph
residue is 0.71 L/min. This value does not vary much with
device.
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4. subject variance, which indicates a stable performance of percentage error (PE = 16.2 %) of our technique is well
IHAR based CO estimation. In many previous CO studies, a below the clinically acceptable error of 30%.
percentage error (PE) is calculated to indicate the variance of A potential limitation of this work is the change of PPG
estimation error with respect to reference mean wave as a result of vascular aging or cardiovascular diseases,
( PE = 1.96SD MEANCO ), and a PE less than 30% is e.g., the inflection point may be blurred and difficult to find
ref
as the arterial stiffness increases. Therefore, further
regarded to be clinically acceptable [9] [10]. The PE of the
validation on subjects with a bigger age range and
results in this study is 16.2 %.
cardiovascular patients are needed. Another limitation is the
TABLE II calibration procedure. Since the main purpose of this study
THE SUMMARY OF THE INTRA-SUBJECT CORRELATION COEFFICIENT r is to propose and evaluate a novel CO index, we have not
BETWEEN COIMP AND IHAR AS WELL AS THE REGRESSION COEFFICIENT
fully investigated the calibration procedure. Only a simple
AND STANDARD DEVIATION (SD) OF RESIDUE IN THE LEAST SQUARE
LINEAR REGRESSION least squares linear regression was utilized. However,
COIPHA = α ⋅ IHAR + β SD of individual calibration is an essential procedure for IHAR
Subject r Residue based CO estimation and will be investigated further in a
α β (L/min) separate study.
S01 0.94﹡ 195.1 3.7 0.83
S02 0.94﹡ 189.6 2.9 0.62
S03 0.78﹡ 265.0 0.9 0.61 REFERENCES
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Fig. 4. Bland-Altman plot of cardiac output.
VI. CONCLUSION
In this study, we have tested the performance of a new CO
index, IHAR, in 16 normotensive subjects through a bicycle
exercise study. The strong intra-subject correlation suggests
that IHAR can successfully trace the CO changes over a
wide dynamic range before and after exercise. The small
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