scholarly journals Non-Invasive Heart Beat Measurement Using Microwave Resonators

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 1002
Author(s):  
Felix Essingholt ◽  
Frederic Meyer ◽  
Peter Kuhn ◽  
Philip Schmidt ◽  
Thorsten Benkner ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Resonance Frequency ◽  
Quality Factor ◽  
Human Body ◽  
Heart Beat ◽  
Proof Of Concept ◽  
Microwave Resonators ◽  
Non Invasive ◽  
First Results

In this paper we present the first results of our research regarding microwave biosensors for non-invasive permittivity monitoring of the human body. To detect permittivity changes, resonators are used, which alter their resonance frequency and their quality factor depending on the permittivity of the material they are placed upon. These permittivity changes may be used as indicators for the heart rate, blood pressure or glucose level. As a proof of concept, this paper focusses on designing resonators to detect the heart beat of humans in the Radial Artery, which is located in the forearm.

scholarly journals Differential effects of the blood pressure state on pulse rate variability and heart rate variability in critically ill patients

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Elisa Mejía-Mejía ◽  
James M. May ◽  
Mohamed Elgendi ◽  
Panayiotis A. Kyriacou
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Pulse Rate ◽  
Pulse Transit Time ◽  
Pulse Rate Variability ◽  
Physiological Factors ◽  
Ecg Signals ◽  
Non Invasive ◽  
Electrocardiogram Ecg

AbstractHeart rate variability (HRV) utilizes the electrocardiogram (ECG) and has been widely studied as a non-invasive indicator of cardiac autonomic activity. Pulse rate variability (PRV) utilizes photoplethysmography (PPG) and recently has been used as a surrogate for HRV. Several studies have found that PRV is not entirely valid as an estimation of HRV and that several physiological factors, including the pulse transit time (PTT) and blood pressure (BP) changes, may affect PRV differently than HRV. This study aimed to assess the relationship between PRV and HRV under different BP states: hypotension, normotension, and hypertension. Using the MIMIC III database, 5 min segments of PPG and ECG signals were used to extract PRV and HRV, respectively. Several time-domain, frequency-domain, and nonlinear indices were obtained from these signals. Bland–Altman analysis, correlation analysis, and Friedman rank sum tests were used to compare HRV and PRV in each state, and PRV and HRV indices were compared among BP states using Kruskal–Wallis tests. The findings indicated that there were differences between PRV and HRV, especially in short-term and nonlinear indices, and although PRV and HRV were altered in a similar manner when there was a change in BP, PRV seemed to be more sensitive to these changes.

scholarly journals Non-Contact Pulse Detector using Video Analytics

2020 ◽  
Vol 9 (5) ◽  
pp. 1597-1600
Keyword(s):  
Computer Vision ◽  
Heart Rate ◽  
Computational Cost ◽  
Heart Beat ◽  
Signal Frequency ◽  
Waiting Room ◽  
Non Invasive ◽  
Safe Side ◽  
Patient Will ◽  
Low Computational Cost

Non-contact pulse detector used for heart beat measurement based on computer vision, where a standard color camera captures the plethysmographic signal and the heart rates are processed and estimated dynamically. It is important that the quantities are taken in a non-invasive manner, which is invisible to the patient. Presently, many methods have been proposed for non-contact measurement. The proposed method based on the computer vision technique is enhanced to overcome the above drawbacks and it requires low computational cost. Many of the hospitals are using surveillance cameras, from these cameras we can monitor the video of the patients waiting in the queue. The camera is attached in the patients’ waiting room and the faces of the patients are monitored. Many factors are considered in the phases of image acquisition, as well as in the plethysmographic signal development, pre-processing and filtering. The pre-filter step uses numerical analysis techniques to cut the signal offset. The proposed method decouples the heart rate from the plethysmographic signal frequency. The proposed system helps in detecting the heart rate of a Patient who is waiting in queue for longer time. Based on the heart rate the seriousness of patient is identified and giving the preference to the patient and treatment will be started, with this the patient will be in safe side.

scholarly journals Pulse Rate Monitoring Embedded System during Indoor Exercises Using Microcontroller

2019 ◽  
Vol 8 (3) ◽  
pp. 2064-2066
Keyword(s):  
Heart Rate ◽  
Embedded System ◽  
Low Cost ◽  
Heart Beat ◽  
Measuring Device ◽  
Non Invasive ◽  
Beat Rate ◽  
Proposed Model ◽  
Measure Heart Rate ◽  
Heart Beat Rate

In the current paper we have described the design, testing and result data of a low cost heart beat measuring device. The proposed model works on the properties of optics. Our model is non-invasive in nature and able to measure heart rate of any individual during different physical activities. We have also developed a better algorithm for measuring heart beat rate at a fixed interval of 5 seconds. The heart beat is counted by a specific microcontroller that displays the heart rate data on an LCD continuously. We have also measured the heart beat rate of an individual running on the trademill at variable speed and compared the result with our model.

scholarly journals Comparison of non-invasive haemodynamic monitors of stress response to endo-tracheal intubation with perfusion index in patients undergoing elective surgery

2020 ◽  
Vol 23 (2) ◽  
pp. 9-13
Author(s):  
Sushila Lama Moktan ◽  
Manan Karki
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Stress Response ◽  
Tracheal Intubation ◽  
Endotracheal Tube ◽  
Diastolic Blood Pressure ◽  
Endotracheal Intubation ◽  
Elective Surgery ◽  
Perfusion Index ◽  
Non Invasive

Introduction: Laryngoscopy and intubation is always associated with a short term reflex sympathetic pressor response. The perfusion index is an indirect, non-invasive, and continuous measure of peripheral perfusion by pulse oximeter which can detect the stress response to intubation similar to heart rate, systolic blood pressure and diastolic blood pressure. Methods: This prospective observational study enrolled sixty-five normotensive patients of American society of anesthesiologists physical status grade I and II scheduled for elective surgery under general anaesthesia. Tracheal intubation was performed after induction with intravenous fentanyl, propofol and vecuronium. Heart rate, Systolic and Diastolic Blood Pressure and Perfusion Index were measured before induction of anesthesia, before intubation and one minute, three minutes, five minutes after the insertion of the endotracheal tube. Increase in heart rate by ?10 beats per minute, systolic and diastolic blood pressure by ?15 millimeters of mercury and decrease in Perfusion index ?10% after endotracheal intubation as compared to preintubationvalue were considered positive haemodynamic changes. Results: Endotracheal intubation produced a significant increase in heart rate and blood pressure whereas perfusion index decreased significantly. Our study showed that perfusion index response criterion achieved 97.7% (Confidence interval 97.58-97.86) sensitivity in detecting the stress response to insertion of endotracheal tube whereas systolic and diastolic blood pressure achieved sensitivity of 90% and 92% respectively. Conclusion: Perfusion Index is easier, reliable and non-invasive alternative to conventional haemodynamic criteria for detection of stress response to endotracheal intubation.

scholarly journals Differential effects of four intramuscular sedatives on cardiorespiratory stability in juvenile guinea pigs (Cavia porcellus)

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259559
Author(s):  
Ryan P. Sixtus ◽  
Cholawat Pacharinsak ◽  
Clint L. Gray ◽  
Mary J. Berry ◽  
Rebecca M. Dyson
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Respiratory Rate ◽  
Guinea Pigs ◽  
Random Order ◽  
Microvascular Perfusion ◽  
Laboratory Animals ◽  
Physiological Monitoring ◽  
Non Invasive ◽  
Effective Doses

Background Non-invasive physiological monitoring can induce stress in laboratory animals. Sedation reduces the level of restraint required, thereby improving the validity of physiological signals measured. However, sedatives may alter physiological equilibrium introducing unintended bias and/or, masking the experimental outcomes of interest. We aimed to investigate the cardiorespiratory effects of four short-acting sedatives in juvenile guinea pigs. Method 12 healthy, 38 (26–46) day-old Dunkin Hartley guinea pigs were included in this blinded, randomised, crossover design study. Animals were sedated by intramuscular injection using pre-established minimum effective doses of either alfaxalone (5 mg/kg), diazepam (5 mg/kg), ketamine (30 mg/kg), or midazolam (2 mg/kg) administered in random order with a minimum washout period of 48 hours between agents. Sedative depth, a composite score comprised of five assessment criteria, was observed every 5-min from dosing until arousal. Physiological monitoring of cardiorespiratory status included measures of heart rate, blood pressure, respiratory rate, and peripheral microvascular perfusion. Results Ketamine and alfaxalone were most effective in inducing stable sedation suitable for physiological monitoring, and diazepam less-so. Midazolam was unsuitable due to excessive hypersensitivity. All sedatives significantly increased heart rate above non-sedated control rates (P<0.0001), without altering blood pressure or microvascular perfusion. Alfaxalone and ketamine reduced respiratory rate relative to their control condition (P<0.0001, P = 0.05, respectively), but within normative ranges. Conclusion Ketamine and alfaxalone are the most effective sedatives for inducing short duration, stable sedation with minimal cardiorespiratory depression in guinea pigs, while diazepam is less-so. However, alfaxalone is the most appropriate sedative for longitudinal studies requiring multiple physiological timepoints.

Maternal hemodynamics during labor epidural analgesia with and without adrenaline: a secondary analysis of a randomized trial

2020 ◽  
Author(s):  
Felix Haidl ◽  
Christian Tronstad ◽  
Leiv Arne Rosseland ◽  
Vegard Dahl
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Epidural Analgesia ◽  
Systolic Blood Pressure ◽  
Secondary Analysis ◽  
Uterine Contractions ◽  
Non Invasive ◽  
Enhance Efficiency ◽  
Labor Epidural

Abstract Background: Pregnancy in general and labor in particular is associated with changes in maternal hemodynamic parameters such as increased cardiac output and heart rate, with peaks during uterine contractions. Adrenaline may be added to labor epidural solutions to enhance efficiency, but the hemodynamic fluctuations may increase. The aim of this study was to compare the hemodynamic changes of epidural drug solution with or without adrenaline 2 µg.ml -1 and to provide pilot data for a larger study. Methods: Forty-one nulliparous laboring women requesting epidural analgesia were randomized to epidural solution of bupivacaine 1mg.ml -1 , fentanyl 2 µg.ml -1 with or without adrenaline 2 µg.ml -1 . The participants were monitored with the Nexfin CC continuous non-invasive blood pressure and cardiac output monitor. The primary outcomes were changes in peak systolic blood pressure and cardiac output at uterine contraction within 30 minutes after epidural activation. The effect of adrenaline was tested statistically by a linear mixed effects model of the outcome variables’ dependency on time, adrenaline and their interaction. Results: The addition of adrenaline to the solution had no statistically significant effect on the temporal changes in peak systolic blood pressure (mean change 0.23 mmHg.min -1 95% CI [-0.17; 0.64] p=0.26), peak cardiac output (mean change 0.0029 l.min -1 .min -1 95 % CI [-0.026; 0.032] 0.84), or heart rate (mean change 0.015 beats.min -1 .min -1 95 % CI [-0.25; 0.28] p=0.91).

scholarly journals Non-invasive wearables for remote monitoring of HbA1c and glucose variability: proof of concept

2021 ◽  
Vol 9 (1) ◽  
pp. e002027
Author(s):  
Brinnae Bent ◽  
Peter J Cho ◽  
April Wittmann ◽  
Connie Thacker ◽  
Srikanth Muppidi ◽  
...  
Keyword(s):  
Heart Rate ◽  
Skin Temperature ◽  
Validation Cohort ◽  
Electrodermal Activity ◽  
External Validation ◽  
Glucose Variability ◽  
Proof Of Concept ◽  
Concept Study ◽  
Non Invasive ◽  
The Relationship

IntroductionDiabetes prevalence continues to grow and there remains a significant diagnostic gap in one-third of the US population that has pre-diabetes. Innovative, practical strategies to improve monitoring of glycemic health are desperately needed. In this proof-of-concept study, we explore the relationship between non-invasive wearables and glycemic metrics and demonstrate the feasibility of using non-invasive wearables to estimate glycemic metrics, including hemoglobin A1c (HbA1c) and glucose variability metrics.Research design and methodsWe recorded over 25 000 measurements from a continuous glucose monitor (CGM) with simultaneous wrist-worn wearable (skin temperature, electrodermal activity, heart rate, and accelerometry sensors) data over 8–10 days in 16 participants with normal glycemic state and pre-diabetes (HbA1c 5.2–6.4). We used data from the wearable to develop machine learning models to predict HbA1c recorded on day 0 and glucose variability calculated from the CGM. We tested the accuracy of the HbA1c model on a retrospective, external validation cohort of 10 additional participants and compared results against CGM-based HbA1c estimation models.ResultsA total of 250 days of data from 26 participants were collected. Out of the 27 models of glucose variability metrics that we developed using non-invasive wearables, 11 of the models achieved high accuracy (<10% mean average per cent error, MAPE). Our HbA1c estimation model using non-invasive wearables data achieved MAPE of 5.1% on an external validation cohort. The ranking of wearable sensor’s importance in estimating HbA1c was skin temperature (33%), electrodermal activity (28%), accelerometry (25%), and heart rate (14%).ConclusionsThis study demonstrates the feasibility of using non-invasive wearables to estimate glucose variability metrics and HbA1c for glycemic monitoring and investigates the relationship between non-invasive wearables and the glycemic metrics of glucose variability and HbA1c. The methods used in this study can be used to inform future studies confirming the results of this proof-of-concept study.

Sign in / Sign up

Export Citation Format

Share Document