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Sensors (Basel, Switzerland) May 2022This work presents an overview of the main strategies that have been proposed for non-invasive monitoring of heart rate (HR) in extramural and home settings. We discuss... (Review)
Review
This work presents an overview of the main strategies that have been proposed for non-invasive monitoring of heart rate (HR) in extramural and home settings. We discuss three categories of sensing according to what physiological effect is used to measure the pulsatile activity of the heart, and we focus on an illustrative sensing modality for each of them. Therefore, electrocardiography, photoplethysmography, and mechanocardiography are presented as illustrative modalities to sense electrical activity, mechanical activity, and the peripheral effect of heart activity. In this paper, we describe the physical principles underlying the three categories and the characteristics of the different types of sensors that belong to each class, and we touch upon the most used software strategies that are currently adopted to effectively and reliably extract HR. In addition, we investigate the strengths and weaknesses of each category linked to the different applications in order to provide the reader with guidelines for selecting the most suitable solution according to the requirements and constraints of the application.
Topics: Electrocardiography; Heart Rate; Monitoring, Physiologic; Photoplethysmography
PubMed: 35684656
DOI: 10.3390/s22114035 -
Journal of Clinical Monitoring and... Aug 2021Calculation of peripheral capillary oxygen saturation [Formula: see text] levels in humans is often made with a pulse oximeter, using photoplethysmography (PPG)...
Calculation of peripheral capillary oxygen saturation [Formula: see text] levels in humans is often made with a pulse oximeter, using photoplethysmography (PPG) waveforms. However, measurements of PPG waveforms are susceptible to motion noise due to subject and sensor movements. In this study, we compare two [Formula: see text]-level calculation techniques, and measure the effect of pre-filtering by a heart-rate tuned comb peak filter on their performance. These techniques are: (1) "Red over Infrared," calculating the ratios of AC and DC components of the red and infrared PPG signals,[Formula: see text], followed by the use of a calibration curve to determine the [Formula: see text] level Webster (in: Design of pulse oximeters, CRC Press, Boca Raton, 1997); and (2) a motion-resistant algorithm which uses the Discrete Saturation Transform (DST) (Goldman in J Clin Monit Comput 16:475-83, 2000). The DST algorithm isolates individual "saturation components" in the optical pathway, which allows separation of components corresponding to the [Formula: see text] level from components corresponding to noise and interference, including motion artifacts. The comparison we provide here (employing the two techniques with and without pre-filtering) addresses two aspects: (1) accuracy of the [Formula: see text] calculations; and (2) computational complexity. We used both synthetic data and experimental data collected from human subjects. The human subjects were tested at rest and while exercising; while exercising, their measurements were subject to the impacts of motion. Our main conclusion is that if an uninterrupted high-quality heart rate measurement is available, then the "Red over Infrared" approach preceded by a heart-rate tuned comb filter provides the preferred trade-off between [Formula: see text]-level accuracy and computational complexity. A modest improvement in [Formula: see text] estimate accuracy at very low SNR environments may be achieved by switching to the pre-filtered DST-based algorithm (up to 6% improvement in [Formula: see text] level accuracy at -10 dB over unfiltered DST algorithm and the filtered "Red over Infrared" approach). However, this improvement comes at a significant computational cost.
Topics: Algorithms; Artifacts; Heart Rate; Humans; Oximetry; Photoplethysmography; Signal Processing, Computer-Assisted
PubMed: 32556842
DOI: 10.1007/s10877-020-00539-2 -
Pediatric Research Jul 2021Continuous heart rate (HR) and oxygenation (SpO) metrics can be useful for predicting adverse events in very low birth weight (VLBW) infants. To optimize the utility of...
BACKGROUND
Continuous heart rate (HR) and oxygenation (SpO) metrics can be useful for predicting adverse events in very low birth weight (VLBW) infants. To optimize the utility of these tools, inter-site variability must be taken into account.
METHODS
For VLBW infants at three neonatal intensive care units (NICUs), we analyzed the mean, standard deviation, skewness, kurtosis, and cross-correlation of electrocardiogram HR, pulse oximeter pulse rate, and SpO. The number and durations of bradycardia and desaturation events were also measured. Twenty-two metrics were calculated hourly, and mean daily values were compared between sites.
RESULTS
We analyzed data from 1168 VLBW infants from birth through day 42 (35,238 infant-days). HR and SpO metrics were similar at the three NICUs, with mean HR rising by ~10 beats/min over the first 2 weeks and mean SpO remaining stable ~94% over time. The number of bradycardia events was higher at one site, and the duration of desaturations was longer at another site.
CONCLUSIONS
Mean HR and SpO were generally similar among VLBW infants at three NICUs from birth through 6 weeks of age, but bradycardia and desaturation events differed in the first 2 weeks after birth. This highlights the importance of developing predictive analytics tools at multiple sites.
IMPACT
HR and SpO analytics can be useful for predicting adverse events in VLBW infants in the NICU, but inter-site differences must be taken into account in developing predictive algorithms. Although mean HR and SpO patterns were similar in VLBW infants at three NICUs, inter-site differences in the number of bradycardia events and duration of desaturation events were found. Inter-site differences in bradycardia and desaturation events among VLBW infants should be considered in the development of predictive algorithms.
Topics: Algorithms; Female; Heart Rate; Humans; Infant, Newborn; Infant, Very Low Birth Weight; Intensive Care Units, Neonatal; Male; Oximetry; Vital Signs
PubMed: 33767372
DOI: 10.1038/s41390-021-01428-3 -
Sensors (Basel, Switzerland) Dec 2023Health-tracking from photoplethysmography (PPG) signals is significantly hindered by motion artifacts (MAs). Although many algorithms exist to detect MAs, the corrupted...
Health-tracking from photoplethysmography (PPG) signals is significantly hindered by motion artifacts (MAs). Although many algorithms exist to detect MAs, the corrupted signal often remains unexploited. This work introduces a novel method able to reconstruct noisy PPGs and facilitate uninterrupted health monitoring. The algorithm starts with spectral-based MA detection, followed by signal reconstruction by using the morphological and heart-rate variability information from the clean segments adjacent to noise. The algorithm was tested on (a) 30 noisy PPGs of a maximum 20 s noise duration and (b) 28 originally clean PPGs, after noise addition (2-120 s) (1) with and (2) without cancellation of the corresponding clean segment. Sampling frequency was 250 Hz after resampling. Noise detection was evaluated by means of accuracy, sensitivity, and specificity. For the evaluation of signal reconstruction, the heart-rate (HR) was compared via Pearson correlation (PC) and absolute error (a) between ECGs and reconstructed PPGs and (b) between original and reconstructed PPGs. Bland-Altman (BA) analysis for the differences in HR estimation on original and reconstructed segments of (b) was also performed. Noise detection accuracy was 90.91% for (a) and 99.38-100% for (b). For the PPG reconstruction, HR showed 99.31% correlation in (a) and >90% for all noise lengths in (b). Mean absolute error was 1.59 bpm for (a) and 1.26-1.82 bpm for (b). BA analysis indicated that, in most cases, 90% or more of the recordings fall within the confidence interval, regardless of the noise length. Optimal performance is achieved even for signals of noise up to 2 min, allowing for the utilization and further analysis of recordings that would otherwise be discarded. Thereby, the algorithm can be implemented in monitoring devices, assisting in uninterrupted health-tracking.
Topics: Photoplethysmography; Algorithms; Artifacts; Electrocardiography; Heart Rate
PubMed: 38203003
DOI: 10.3390/s24010141 -
Comparative Medicine Feb 2022Acute spinal cord injury (ASCI) is a devastating event that can have severe hemodynamic consequences, depending on location and severity of the lesion. Knowledge of...
Acute spinal cord injury (ASCI) is a devastating event that can have severe hemodynamic consequences, depending on location and severity of the lesion. Knowledge of hyperacute hemodynamic changes is important for researchers using porcine models of thoracic ASCI. The goal of this study was to determine the hyperacute hemodynamic changes observed after ASCI when using pigs as their own controls. Five Yucatan gilts were anesthetized, and a dorsal laminectomy performed at T10-T12. Standardized blunt trauma was applied for 5 consecutive min, and hemodynamic variables were collected 5 min before ASCI, and at 2, 4, 6, 8, 10, 20, 30, 60, 80 and 120 min after ASCI. Arterial blood gas samples were collected at 60 min and 10 min before, and at 30 min and between 120 and 240 min after ASCI. Parametric data were analyzed using a mixed effects model with time point as the fixed factor and subject as the random factor. We found no effect on heart rate, pulse pressure, SpO₂, EtCO₂, and respiratory rate between baseline and timepoints after ASCI. Diastolic arterial pressure, mean arterial pressure, and systolic arterial pressure fell significantly by 18%, 16%, and 15%, respectively, at 2 min after ASCI. However, none of the decrements in arterial pressures resulted in hypotension at any time point. Heart rate did not change significantly after ASCI. Blood glucose progressively increased to 50% above baseline between 120 and 240 minutes after ASCI. Low thoracic ASCI caused a consistent and statistically significant but clinically minor hyperacute decrease in arterial pressures (-15%) that did not produce hypotension or metabolic changes suggestive of tissue hypoperfusion. Our findings using this model suggest that mean arterial pressures should be maintained above 85 mm Hg prior to spinal trauma in order to avoid hypotensive states after ASCI.
Topics: Animals; Blood Pressure; Female; Heart Rate; Hemodynamics; Hypotension; Spinal Cord Injuries; Swine
PubMed: 34814974
DOI: 10.30802/AALAS-CM-21-000067 -
Respiratory Medicine 2023Pulse rate variability (PRV) predicts stroke in patients with sleep disordered breathing (SDB). However, the relationship between PRV and cardiovascular disease (CVD)...
OBJECTIVES
Pulse rate variability (PRV) predicts stroke in patients with sleep disordered breathing (SDB). However, the relationship between PRV and cardiovascular disease (CVD) was unknown in SDB.
METHODS
This was a cross-sectional study. Community residents in Guangdong were investigated. Sleep study were conducted with a type Ⅳ sleep monitoring. PRV parameters was assessed from the pulse waveforms derived from the sleep monitoring.
RESULTS
3747 participants were enrolled. The mean age was 53.9 ± 12.7 years. 1149 (30.7%) were diagnosed as SDB. PRV parameters, except for the averages of pulse-to-pulse intervals (ANN), were higher in participants with SDB than those without. After adjusting for traditional CVD risk factors, deceleration capacity of rate (DC), ANN, and the percentage of pulse-to-pulse interval differences that were more than 50 ms (PNN50) were correlated with CVD risk in participants with SDB (OR were 0.826, 1.002, and 1.285; P were 0.003, 0.009, and 0.010), but not in participants without SDB. There was no interaction effect between DC, ANN, PNN50 and oxygen desaturation index. In hierarchical analysis, DC and ANN were predictors for CVD in SDB patients with age <60 years, male, overweight, diabetes, and normal lipid metabolism. PNN50 was predictor for CVD in the elderly SDB patients without overweight, diabetes or dyslipidemia.
CONCLUSIONS
PRV parameters may be specific predictors for CVD in SDB. PNN50 was a potent biomarker for CVD risk in the elderly with SDB, event without traditional CVD risk factors.
Topics: Humans; Male; Aged; Adult; Middle Aged; Cardiovascular Diseases; Polysomnography; Overweight; Heart Rate; Cross-Sectional Studies; Sleep Apnea Syndromes; Sleep; Diabetes Mellitus
PubMed: 37734671
DOI: 10.1016/j.rmed.2023.107408 -
PloS One 2023Heart failure is a chronic progressive disease in which the heart muscle is unable to pump enough blood to meet the body's need. It is a severe health problem around the...
INTRODUCTION
Heart failure is a chronic progressive disease in which the heart muscle is unable to pump enough blood to meet the body's need. It is a severe health problem around the world with high re-hospitalization and death rates. The main aim of this study was to identify the factors associated with longitudinal change of pulse rate and survival time to death of congestive heart failure patients treated at Arba Minch General Hospital.
METHODS
A retrospective study design was undertaken on congestive heart failure patients admitted to the Arba Minch General Hospital from January 2017 to December 2020. Data was collected from a total of 199 patients. After evaluating the longitudinal data with a linear mixed model and the survival time to death data with cox proportional model, Bayesian joint model of both sub models was fitted in R software using JMbayes2 package.
RESULTS
Findings from Bayesian joint model revealed that the estimated value for the association parameter was positive and statistically significant. This indicates that there is significant evidence of an association between the mean longitudinal change of pulse rate and the risk of death. Weight of patients at baseline, gender, chronic kidney disease, left ventricular ejection fraction, New York Heart Association classification, diabetes, tuberculosis, pneumonia and family history were statistically significant factors associated with mean evolution of pulse rate of congestive heart failure patients. Left ventricular ejection fraction, etiology of congestive heart failure, type of congestive heart failure, chronic kidney disease, smoking, family history, alcohol and diabetes were found to be statistically significant factors associated with survival time to death.
CONCLUSION
To reduce the risk level, health professionals should give attention to congestive heart failure patients with high pulse rate, co-morbidities of chronic kidney disease, tuberculosis, diabetic, smoking status, family history, and pneumonia in the study area.
Topics: Humans; Heart Rate; Bayes Theorem; Ethiopia; Hospitals, General; Retrospective Studies; Stroke Volume; Ventricular Function, Left; Heart Failure
PubMed: 36881600
DOI: 10.1371/journal.pone.0282637 -
Scientific Reports Sep 2021Lung diseases have high mortality and morbidity, with an important impact on quality of life. Hypoxemic patients are advised to use oxygen therapy to prolong their... (Comparative Study)
Comparative Study Observational Study
Lung diseases have high mortality and morbidity, with an important impact on quality of life. Hypoxemic patients are advised to use oxygen therapy to prolong their survival, but high oxygen saturation (SpO) levels can also have negative effects. Pulse oximeters are the most common way to assess oxygen levels and guide medical treatment. This study aims to assess whether wearable devices can provide precise SpO measurements when compared to commercial pulse oximeters. This is a cross-section study with 100 patients with chronic obstructive pulmonary disease and interstitial lung disease from an outpatient pneumology clinic. SpO and heart rate data were collected with an Apple Watch Series 6 (Apple) and compared to two commercial pulse oximeters. The Bland-Altman method and interclass correlation coefficient were used to compare their values. We observed strong positive correlations between the Apple Watch device and commercial oximeters when evaluating heart rate measurements (r = 0.995, p < 0.001) and oximetry measurements (r = 0.81, p < 0.001). There was no statistical difference in the evaluation of skin color, wrist circumference, presence of wrist hair, and enamel nail for SpO and heart rate measurements in Apple Watch or commercial oximeter devices (p > 0.05). Apple Watch 6 is a reliable way to obtain heart rate and SpO in patients with lung diseases in a controlled environment.
Topics: Aged; Cross-Sectional Studies; Female; Healthy Volunteers; Heart Rate; Humans; Lung Diseases, Interstitial; Male; Middle Aged; Oximetry; Oxygen Saturation; Pulmonary Disease, Chronic Obstructive; Reproducibility of Results; Wearable Electronic Devices; Wrist
PubMed: 34556765
DOI: 10.1038/s41598-021-98453-3 -
Scientific Reports Jan 2020Availability of daily continuous blood pressure (DCBP) has a strong impact to realization of healthy society. However, existing methods to obtain blood pressure of cuff... (Observational Study)
Observational Study
Availability of daily continuous blood pressure (DCBP) has a strong impact to realization of healthy society. However, existing methods to obtain blood pressure of cuff type and cuff-less types utilizing correlation with pulse waveform, pulse transit time or pulse rate; or computation of circulation model are not suitable to obtain DCBP. Here we implemented a method based on a simple circulatory system model using pulse rate measurement to overcome the limitations, and showed that it provides appropriate estimation of DCBP. The present model consists of a circulatory dynamic system model and an inverse model of a circulatory control system with input of pulse rate and six model parameters representing standard pulse rate, elasticity of systemic arteries, peripheral vascular resistance, and characteristics of resistance and stroke volume control. Validity of the DCBP estimation method was examined by preliminary experiment for one subject in four days and that for four subjects in one day. DCBP estimation was performed with 24-hour pulse rate measurement by a wearable device and sphygmomanometer measurement for parameter determination and verification. Mean absolute errors in systolic/diastolic pressures were appropriate ones for preliminary experiments with 9.4/6.4 mmHg in four days and 7.3/5.9 mmHg in five subjects.
Topics: Adult; Blood Pressure; Blood Pressure Monitoring, Ambulatory; Blood Pressure Monitors; Healthy Volunteers; Heart Rate; Humans; Male; Middle Aged; Models, Cardiovascular; Stroke Volume; Vascular Resistance; Wearable Electronic Devices; Young Adult
PubMed: 31996723
DOI: 10.1038/s41598-020-58367-y -
Computer Methods and Programs in... Feb 2022As a common pathological pulse, unsmooth pulse has important diagnostic value in traditional Chinese medicine (TCM). In modern pulse diagnosis, unsmooth pulse plays an...
BACKGROUND AND OBJECTIVE
As a common pathological pulse, unsmooth pulse has important diagnostic value in traditional Chinese medicine (TCM). In modern pulse diagnosis, unsmooth pulse plays an important role in the diagnosis of disease location and nature, but there are few studies on it. In this paper, a pulse diagnosis approach based on acoustic waveforms was proposed, the wrist pulse was divided into five layers vertically for the first time. Five layers acoustic waves of the radial artery in stable coronary heart disease (CHD) patients and relatively healthy people were compared to explore whether there are abnormal changes in acoustic pulse in stable CHD patients.
METHODS
The acoustic features of unsmooth pulse in patients with stable CHD were analyzed in time domain, frequency domain and empirical mode decomposition, combined with shannon entropy and multi-scale entropy. Sixteen pulse characteristics were discovered, and one-way analysis of variance were performed. The characteristics of the two groups were tested by T test. 13 features were used to identify patients with stable CHD by support vector machine (SVM).
RESULTS
Compared to healthy people, all parameters of the third layer of the stable CHD left Cun pulse were significantly different from those of the healthy people. The identification rates of the fourth and third layer of the left Cun pulse were the first (90.79%) and the second (88.16%), respectively.
CONCLUSION
Abnormal acoustic pulse appeared in the radial artery in patients with stable CHD. According to these changes, patients with stable CHD can be effectively identified from the perspective of pulse.
Topics: Acoustics; Coronary Disease; Heart Rate; Humans; Medicine, Chinese Traditional; Wrist
PubMed: 34861617
DOI: 10.1016/j.cmpb.2021.106550