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Medicine Nov 2023To explore the feasibility of using micro-bolus pulse injection method to reduce the dilution effect of pipeline on high concentration injection, and to understand low...
To explore the feasibility of using micro-bolus pulse injection method to reduce the dilution effect of pipeline on high concentration injection, and to understand low liquid volume bolus injection based on low injection speed. Using a programmable pulse injection pump, a 25-cm - long pipeline containing water-soluble fluorescent agent was flushed using different volumes of bolus, and the time spent for the complete disappearance of the fluorescent agent was recorded to evaluate the flushing efficiency. The finite element simulation of 2-phase flow was carried out using computational fluid dynamics (CFD) technology, and the difference of shear rate and pressure distribution in the vein of pulse injection and direct injection of bolus under hemostasis was compared and simulated. Micro-bolus pulse flushing has advantages in completing perfusion imaging applications, such as small volume imaging agent injection. Compared with non-pulse injection, the effective flushing volume decreases by 49.7%, the average injection speed decreases by 56%, and the maintenance time of high shear rate is shorter when using micro-bolus pulse injection. The impact of micro-bolus pulse injection on the vein can achieve the same or even lower negative effects as other injection methods after increasing the hemostatic distance to 100 mm. In the case of bolus injection requiring high concentration and small volume, such as for radiopharmaceutical dynamic imaging, the application of micro-bolus pulse injection is an effective way to overcome the dilution phenomenon of the imaging agent in the pipeline. During hemostasis, the micro-bolus pulse injection needs to control a longer hemostasis distance to reduce the potential impact on peripheral veins.
Topics: Humans; Injections; Veins; Computer Simulation; Heart Rate; Hemostasis
PubMed: 37933034
DOI: 10.1097/MD.0000000000035607 -
Estimating age and gender from electrocardiogram signals: A comprehensive review of the past decade.Artificial Intelligence in Medicine Dec 2023Twelve lead electrocardiogram signals capture unique fingerprints about the body's biological processes and electrical activity of heart muscles. Machine learning and... (Review)
Review
Twelve lead electrocardiogram signals capture unique fingerprints about the body's biological processes and electrical activity of heart muscles. Machine learning and deep learning-based models can learn the embedded patterns in the electrocardiogram to estimate complex metrics such as age and gender that depend on multiple aspects of human physiology. ECG estimated age with respect to the chronological age reflects the overall well-being of the cardiovascular system, with significant positive deviations indicating an aged cardiovascular system and a higher likelihood of cardiovascular mortality. Several conventional, machine learning, and deep learning-based methods have been proposed to estimate age from electronic health records, health surveys, and ECG data. This manuscript comprehensively reviews the methodologies proposed for ECG-based age and gender estimation over the last decade. Specifically, the review highlights that elevated ECG age is associated with atherosclerotic cardiovascular disease, abnormal peripheral endothelial dysfunction, and high mortality, among many other cardiovascular disorders. Furthermore, the survey presents overarching observations and insights across methods for age and gender estimation. This paper also presents several essential methodological improvements and clinical applications of ECG-estimated age and gender to encourage further improvements of the state-of-the-art methodologies.
Topics: Humans; Aged; Signal Processing, Computer-Assisted; Electrocardiography; Machine Learning; Heart Rate; Probability
PubMed: 38042607
DOI: 10.1016/j.artmed.2023.102690 -
Sensors (Basel, Switzerland) Jul 2023Skin temperature reflects the Autonomic Nervous System (ANS)'s response to emotions and mental states and can be remotely measured using InfraRed Thermography....
Skin temperature reflects the Autonomic Nervous System (ANS)'s response to emotions and mental states and can be remotely measured using InfraRed Thermography. Understanding the physiological mechanisms that affect facial temperature is essential to improve the precision of emotional inference from thermal imaging. To achieve this aim, we recorded thermal images from 30 volunteers, at rest and under acute stress induced by the Stroop test, together with two autonomic correlates, i.e., heart rate variability and electrodermal activity, the former serving as a measure of cardiovascular dynamics, and the latter of the activity of the sweat glands. We used a Cross Mapping (CM) approach to quantify the nonlinear coupling of the temperature from four facial regions with the ANS correlates. CM reveals that facial temperature has a statistically significant correlation with the two autonomic time series, under both conditions, which was not evident in the linear domain. In particular, compared to the other regions, the nose shows a significantly higher link to the electrodermal activity in both conditions, and to the heart rate variability under stress. Moreover, the cardiovascular activity seems to be primarily responsible for the well-known decrease in nose temperature, and its coupling with the thermal signals significantly varies with gender.
Topics: Humans; Temperature; Body Temperature; Skin Temperature; Emotions; Autonomic Nervous System; Heart Rate
PubMed: 37514696
DOI: 10.3390/s23146403 -
Sensors (Basel, Switzerland) Sep 2023Cardio-mechanical monitoring techniques, such as Seismocardiography (SCG) and Gyrocardiography (GCG), have received an ever-growing interest in recent years as potential...
Cardio-mechanical monitoring techniques, such as Seismocardiography (SCG) and Gyrocardiography (GCG), have received an ever-growing interest in recent years as potential alternatives to Electrocardiography (ECG) for heart rate monitoring. Wearable SCG and GCG devices based on lightweight accelerometers and gyroscopes are particularly appealing for continuous, long-term monitoring of heart rate and its variability (HRV). Heartbeat detection in cardio-mechanical signals is usually performed with the support of a concurrent ECG lead, which, however, limits their applicability in standalone cardio-mechanical monitoring applications. The complex and variable morphology of SCG and GCG signals makes the ECG-free heartbeat detection task quite challenging; therefore, only a few methods have been proposed. Very recently, a template matching method based on normalized cross-correlation (NCC) has been demonstrated to provide very accurate detection of heartbeats and estimation of inter-beat intervals in SCG and GCG signals of pathological subjects. In this study, the accuracy of HRV indices obtained with this template matching method is evaluated by comparison with ECG. Tests were performed on two public datasets of SCG and GCG signals from healthy and pathological subjects. Linear regression, correlation, and Bland-Altman analyses were carried out to evaluate the agreement of 24 HRV indices obtained from SCG and GCG signals with those obtained from ECG signals, simultaneously acquired from the same subjects. The results of this study show that the NCC-based template matching method allowed estimating HRV indices from SCG and GCG signals of healthy subjects with acceptable accuracy. On healthy subjects, the relative errors on time-domain indices ranged from 0.25% to 15%, on frequency-domain indices ranged from 10% to 20%, and on non-linear indices were within 8%. The estimates obtained on signals from pathological subjects were affected by larger errors. Overall, GCG provided slightly better performances as compared to SCG, both on healthy and pathological subjects. These findings provide, for the first time, clear evidence that monitoring HRV via SCG and GCG sensors without concurrent ECG is feasible with the NCC-based template matching method for heartbeat detection.
Topics: Humans; Heart Rate; Electrocardiography; Heart; Monitoring, Physiologic; Heart Rate Determination
PubMed: 37836942
DOI: 10.3390/s23198114 -
Nefrologia 2023Preeclampsia (PE) is a hypertensive disorder of pregnancy associated with high maternal and fetal morbidity and mortality and increased future risk of cardiovascular...
BACKGROUND
Preeclampsia (PE) is a hypertensive disorder of pregnancy associated with high maternal and fetal morbidity and mortality and increased future risk of cardiovascular complications.
OBJECTIVE
To analyze whether women who have had PE with severe features in their pregnancy have higher arterial stiffness (AS) parameters than those whose PE course was without signs of severity.
METHODS
Sixty-five women who developed PE during their gestation were evaluated, divided into two groups: PE group without severe features or non-severe PE (n=30) and PE group with severe features or severe PE (n=35). Carotid-femoral pulse wave velocity (cfPWV), central augmentation index corrected to a heart rate of 75 beats per minute (AIxc75) and central augmentation pressure (cAP) were determined one month and six months postpartum. Comparison of proportions was carried out using the chi-square test, comparison of means between groups using the Student's t-test or the Mann-Whitney test, and comparison of means of the same group at different evolutionary moments, using the t-test or the Wilcoxon test. Correlation, with and between hemodynamic parameters, was carried out with Spearman's correlation coefficient and the association between demographic variables, personal history and hemodynamic parameters, and altered arterial stiffness parameters was carried out using linear and logistic regression models.
RESULTS
Women with severe PE presented, both at 1 and 6 months postpartum, higher values of blood pressure, both central and peripheral, as well as AR and pulse amplification parameters, than those women whose PE was not severe. Central augmentation index (cAIx) values at 1 month and 6 months postpartum were higher, although not significantly, in the severe PE group compared to the non-severe PE group (24.0 (16.5-34.3) vs. 19.0% (14-29) and 24.0 (14.0-30.0) vs. 20.0% (12.3-26.8), respectively). Carotid-femoral pulse wave velocity (cfPWV) was significantly higher at both 1 and 6 months postpartum in the severe PE group compared to the non-severe PE group (10.2 (8.8-10.7) vs. 8.8m/s (8.3-9.6) and 10.0 (8.8-10.6) vs. 8.8m/s (8.3-9.3), respectively). Central systolic pressure and central pulse pressure amplification were also higher, although not significantly, in the severe PE group in comparison with the non-severe PE group.
CONCLUSIONS
Women who have had severe PE have more pronounced arterial stiffness parameters than those in whom PE was not particularly severe. The determination of cAIx and cfPWV, as a strategy for the assessment of cardiovascular risk, should be evaluated among women who have had PE.
Topics: Pregnancy; Humans; Female; Pre-Eclampsia; Pulse Wave Analysis; Vascular Stiffness; Blood Pressure; Heart Rate
PubMed: 38199838
DOI: 10.1016/j.nefroe.2023.12.001 -
Journal of the American Heart... Dec 2023
Topics: Humans; Adult; Cardiovascular Diseases; Cohort Studies; Heart Rate; Risk Factors; Kidney Failure, Chronic; Kidney Diseases
PubMed: 38038191
DOI: 10.1161/JAHA.123.032580 -
Experimental Physiology Mar 2024The dive response, or the 'master switch of life', is probably the most studied physiological trait in marine mammals and is thought to conserve the available O for the... (Review)
Review
The dive response, or the 'master switch of life', is probably the most studied physiological trait in marine mammals and is thought to conserve the available O for the heart and brain. Although generally thought to be an autonomic reflex, several studies indicate that the cardiovascular changes during diving are anticipatory and can be conditioned. The respiratory adaptations, where the aquatic breathing pattern resembles intermittent breathing in land mammals, with expiratory flow exceeding 160 litres s has been measured in cetaceans, and where exposure to extreme pressures results in alveolar collapse (atelectasis) and recruitment upon ascent. Cardiorespiratory coupling, where breathing results in changes in heart rate, has been proposed to improve gas exchange. Cardiorespiratory coupling has also been reported in marine mammals, and in the bottlenose dolphin, where it alters both heart rate and stroke volume. When accounting for this respiratory dependence on cardiac function, several studies have reported an absence of a diving-related bradycardia except during dives that exceed the duration that is fuelled by aerobic metabolism. This review summarizes what is known about the respiratory physiology in marine mammals, with a special focus on cetaceans. The cardiorespiratory coupling is reviewed, and the selective gas exchange hypothesis is summarized, which provides a testable mechanism for how breath-hold diving vertebrates may actively prevent uptake of N during routine dives, and how stress results in failure of this mechanism, which results in diving-related gas emboli.
Topics: Animals; Diving; Mammals; Bradycardia; Heart Rate; Respiration
PubMed: 37968859
DOI: 10.1113/EP091095 -
Physics in Medicine and Biology Aug 2023. The objective of this study was to investigate the impact of mean and instantaneous dose rates on the production of reactive oxygen species (ROS) during ultra-high...
. The objective of this study was to investigate the impact of mean and instantaneous dose rates on the production of reactive oxygen species (ROS) during ultra-high dose rate (UHDR) radiotherapy. The study aimed to determine whether either dose rate type plays a role in driving the FLASH effect, a phenomenon where UHDR radiotherapy reduces damage to normal tissues while maintaining tumor control.. Assays of hydrogen peroxide (HO) production and oxygen consumption (ΔpO) were conducted using UHDR electron irradiation. Aqueous solutions of 4% albumin were utilized as the experimental medium. The study compared the effects of varying mean dose rates and instantaneous dose rates on ROS yields. Instantaneous dose rate was varied by changing the source-to-surface distance (SSD), resulting in instantaneous dose rates ranging from 10to 10Gy s. Mean dose rate was manipulated by altering the pulse frequency of the linear accelerator (linac) and by changing the SSD, ranging from 0.14 to 1500 Gy s.. The study found that both ΔHOand ΔpOdecreased as the mean dose rate increased. Multivariate analysis indicated that instantaneous dose rates also contributed to this effect. The variation in ΔpOwas dependent on the initial oxygen concentration in the solution. Based on the analysis of dose rate variation, the study estimated that 7.51 moles of HOwere produced for every mole of Oconsumed.. The results highlight the significance of mean dose rate as a predictor of ROS production during UHDR radiotherapy. As the mean dose rate increased, there was a decrease in oxygen consumption and in HOproduction. These findings have implications for understanding the FLASH effect and its potential optimization. The study sheds light on the role of dose rate parameters and their impact on radiochemical outcomes, contributing to the advancement of UHDR radiotherapy techniques.
Topics: Reactive Oxygen Species; Electrons; Hydrogen Peroxide; Oxygen; Heart Rate; Radiotherapy Dosage
PubMed: 37463588
DOI: 10.1088/1361-6560/ace877 -
Sensors (Basel, Switzerland) Aug 2023: The advancement of preventive medicine and, subsequently, telemedicine drives the need for noninvasive and remote measurements in patients' natural environments. Heart...
: The advancement of preventive medicine and, subsequently, telemedicine drives the need for noninvasive and remote measurements in patients' natural environments. Heart rate (HR) measurements are particularly promising and extensively researched due to their quick assessment and comprehensive representation of patients' conditions. However, in scenarios such as endurance training or emergencies, where HR measurement was not anticipated and direct access to victims is limited, no method enables obtaining HR results that are suitable even for triage. : This paper presents the possibility of remotely measuring of human HR from a series of in-flight videos using videoplethysmography (VPG) along with skin detection, human pose estimation and image stabilization methods. An unmanned aerial vehicle (UAV) equipped with a camera captured ten segments of video footage featuring volunteers engaged in free walking and running activities in natural sunlight. The human pose was determined using the OpenPose algorithm, and subsequently, skin areas on the face and forearms were identified and tracked in consecutive frames. Ultimately, HR was estimated using several VPG methods: the green channel (G), green-red difference (GR), excess green (ExG), independent component analysis (ICA), and a plane orthogonal to the skin (POS). : When compared to simultaneous readings from a reference ECG-based wearable recorder, the root-mean-squared error ranged from 17.7 (G) to 27.7 (POS), with errors of less than 3.5 bpm achieved for the G and GR methods. : These results demonstrate the acceptable accuracy of touchless human pulse measurement with the accompanying UAV-mounted camera. The method bridges the gap between HR-transmitting wearables and emergency HR recorders, and it has the potential to be advantageous in training or rescue scenarios in mountain, water, disaster, or battlefield settings.
Topics: Humans; Heart Rate Determination; Unmanned Aerial Devices; Heart Rate; Algorithms; Disasters
PubMed: 37631834
DOI: 10.3390/s23167297 -
Complementary Therapies in Medicine Oct 2023Clarifying the effect of music on pain endurance in an experimental design could aid in how music should be applied during both surgical and non-surgical interventions.... (Randomized Controlled Trial)
Randomized Controlled Trial
INTRODUCTION
Clarifying the effect of music on pain endurance in an experimental design could aid in how music should be applied during both surgical and non-surgical interventions. This study aims to investigate the effect of music on pain endurance and the involvement of the sympathetic adrenomedullary axis (SAM) and the hypothalamic-pituitary-adrenocortical axis (HPA).
MATERIALS AND METHODS
In this randomized controlled trial all participants received increasing electric stimuli through their non-dominant index finger. Participants were randomly assigned to the music group (M) receiving a 20-minute music intervention or control group (C) receiving a 20-minute resting period. The primary outcome was pain endurance, defined as amount milliampere tolerated. Secondary outcomes included anxiety level, SAM-axis based on heart rate variability (HRV) and salivary alpha-amylase, and HPA-axis activity based on salivary cortisol.
RESULTS
In the intention-to-treat analysis, the effect of music on pain tolerance did not statistically differ between the M and C group. A significant positive effect of music on pain endurance was noted after excluding participants with a high skin impedance (p = 0.013, CI 0.35; 2.85). Increased HRV was observed in the M-group compared to the C-group for SDNN (B/95%CI:13.80/2.22;25.39, p = 0.022), RMSSD (B/95%CI:15.97/1.64;30.31, p = 0.032), VLF (B/95%CI:212.08/60.49;363.67, p = 0.008) and HF (B/95%CI:821.15/150.78;1491.52, p = 0.0190). No statistical significance was observed in other secondary outcomes.
CONCLUSIONS
The effect of the music intervention on pain endurance was not statistically significant in the intention-to-treat analysis. The subgroup analyses revealed an increase in pain endurance in the music group after correcting for skin impedance, which could be attributed to increased parasympathetic activation.
Topics: Humans; Music; Pain; Music Therapy; Heart Rate; Pain Threshold; Anxiety
PubMed: 37579996
DOI: 10.1016/j.ctim.2023.102969