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Anaesthesia Nov 2022We performed a systematic review and meta-analysis to identify, classify and evaluate the body of evidence on novel wearable and contactless devices that measure heart... (Meta-Analysis)
Meta-Analysis Review
We performed a systematic review and meta-analysis to identify, classify and evaluate the body of evidence on novel wearable and contactless devices that measure heart rate, respiratory rate and oxygen saturations in the clinical setting. We included any studies of hospital inpatients, including sleep study clinics. Eighty-four studies were included in the final review. There were 56 studies of wearable devices and 29 of contactless devices. One study assessed both types of device. A high risk of patient selection and rater bias was present in proportionally more studies assessing contactless devices compared with studies assessing wearable devices (p = 0.023 and p < 0.0001, respectively). There was high but equivalent likelihood of blinding bias between the two types of studies (p = 0.076). Wearable device studies were commercially available devices validated in acute clinical settings by clinical staff and had more real-time data analysis (p = 0.04). Contactless devices were more experimental, and data were analysed post-hoc. Pooled estimates of mean (95%CI) heart rate and respiratory rate bias in wearable devices were 1.25 (-0.31-2.82) beats.min (pooled 95% limits of agreement -9.36-10.08) and 0.68 (0.05-1.32) breaths.min (pooled 95% limits of agreement -5.65-6.85). The pooled estimate for mean (95%CI) heart rate and respiratory rate bias in contactless devices was 2.18 (3.31-7.66) beats.min (pooled limits of agreement -6.71-10.88) and 0.30 (-0.26-0.87) breaths.min (pooled 95% limits of agreement -3.94-4.29). Only two studies of wearable devices measured S O ; these reported mean measurement biases of 3.54% (limits of agreement -5.65-11.45%) and 2.9% (-7.4-1.7%). Heterogeneity was observed across studies, but absent when devices were grouped by measurement modality and reference standard. We conclude that, while studies of wearable devices were of slightly better quality than contactless devices, in general all studies of novel devices were of low quality, with small (< 100) patient datasets, typically not blinded and often using inappropriate statistical techniques. Both types of devices were statistically equivalent in accuracy and precision, but wearable devices demonstrated less measurement bias and more precision at extreme vital signs. The statistical variability in precision and accuracy between studies is partially explained by differences in reference standards.
Topics: Heart Rate; Humans; Monitoring, Physiologic; Oxygen; Oxygen Saturation; Respiratory Rate; Wearable Electronic Devices
PubMed: 35947876
DOI: 10.1111/anae.15834 -
Noninvasive Non-Contact SpO Monitoring Using an Integrated Polarization-Sensing CMOS Imaging Sensor.Sensors (Basel, Switzerland) Oct 2022In the diagnosis and primary health care of an individual, estimation of the pulse rate and blood oxygen saturation (SpO2) is critical. The pulse rate and SpO2 are...
BACKGROUND
In the diagnosis and primary health care of an individual, estimation of the pulse rate and blood oxygen saturation (SpO2) is critical. The pulse rate and SpO2 are determined by methods including photoplethysmography (iPPG), light spectroscopy, and pulse oximetry. These devices need to be compact, non-contact, and noninvasive for real-time health monitoring. Reflection-based iPPG is becoming popular as it allows non-contact estimation of the heart rate and SpO2. Most iPPG methods capture temporal data and form complex computations, and thus real-time measurements and spatial visualization are difficult.
METHOD
In this research work, reflective mode polarized imaging-based iPPG is proposed. For polarization imaging, a custom image sensor with wire grid polarizers on each pixel is designed. Each pixel has a wire grid of varying transmission axes, allowing phase detection of the incoming light. The phase information of the backscattered light from the fingertips of 12 healthy volunteers was recorded in both the resting as well as the excited states. These data were then processed using MATLAB 2021b software.
RESULTS
The phase information provides quantitative information on the reflection from the superficial and deep layers of skin. The ratio of deep to superficial layer backscattered phase information is shown to be directly correlated and linearly increasing with an increase in the SpO2 and heart rate.
CONCLUSIONS
The phase-based measurements help to monitor the changes in the resting and excited state heart rate and SpO2 in real time. Furthermore, the use of the ratio of phase information helps to make the measurements independent of the individual skin traits and thus increases the accuracy of the measurements. The proposed iPPG works in ambient light, relaxing the instrumentation requirement and helping the system to be compact and portable.
Topics: Humans; Oximetry; Photoplethysmography; Monitoring, Physiologic; Heart Rate; Fingers; Oxygen
PubMed: 36298147
DOI: 10.3390/s22207796 -
Journal of Dairy Science Jul 2018Pulse oximetry is a well-established technique in human and veterinary medicine. In farm animals, it could also be a useful tool for the detection of critical conditions...
Pulse oximetry is a well-established technique in human and veterinary medicine. In farm animals, it could also be a useful tool for the detection of critical conditions relating to oxygen supply and the cardiovascular system. Among other uses, an innovative application could be the monitoring of fetuses during birth. This could help in the early identification of critical situations and support farmers and veterinarians in their decision to start obstetric or life-support interventions. Until now, however, its use in ruminant medicine was still limited to experimental applications. The objective of this study was to evaluate the accuracy of the Radius-7 Wearable Pulse CO-Oximeter (Masimo Corporation, Irvine, CA) for monitoring vital parameters in newborn calves. All measurements were conducted on animals in the lying down position. The sensor of the pulse oximeter was placed in the interdigital space of the calves' front legs and fixed with a homemade latex hoof cover. The pulsoximetric measurements of arterial oxygen saturation (SpO) in 40 newborn calves were compared with the corresponding results (SaO) from a portable blood gas analyzer (VetScan iStat1, Abaxis Inc., Union City, CA), which served as the reference. For this, an arterial blood sample was taken from the medial intermediate branch of the caudal auricular artery. In addition, the pulse rate was measured in 10 calves aged between 0 and 7 d with the pulse oximeter and simultaneously with a heart rate belt (Polar Equine Belt, Polar Electro Oy, Kempele, Finland) to determine their level of agreement. Spearman correlation coefficient for oxygen saturation was 93.8% for the pulse oximeter and the blood gas analyzer, and 97.7% for the pulse rate measured with the pulse oximeter and the heart rate belt. Bland-Altman plots revealed an overestimation of SaO by 2.95 ± 6.39% and an underestimation of the pulse rate by -0.41 ± 3.18 beats per minute compared with the corresponding reference methods. In summary, the pulse oximeter is suitable for continuous monitoring of arterial oxygen saturation and pulse in newborn Holstein Friesian calves. For practical use, purpose-built technical equipment is required to attach the sensor to the calves' legs.
Topics: Animals; Blood Gas Analysis; Cattle; Heart Rate; Humans; Oximetry; Oxygen
PubMed: 29705429
DOI: 10.3168/jds.2017-14266 -
Journal of Dairy Science Nov 2016The objective of this study was to assess the oxygen pulse and heart rate (OP-HR) technique using the respiration chamber (RC) and comparative slaughter (CS) methods for... (Randomized Controlled Trial)
Randomized Controlled Trial
The objective of this study was to assess the oxygen pulse and heart rate (OP-HR) technique using the respiration chamber (RC) and comparative slaughter (CS) methods for measuring the heat production (HP) of crossbred (Holstein × Gyr) yearling bulls. Twenty-four bulls were used. Six bulls were slaughtered at the beginning of the experiment as a reference group to estimate the initial empty body weight (BW) and energy content of the remaining animals. The remaining bulls were assigned to a completely randomized design with 3 levels of dry matter intake, with 6 replicates. The levels of dry matter intake were 1.2% of BW, 1.8% of BW and ad libitum, with target orts of 5%. The bulls were fed a diet consisting of 59.6% corn silage and 40.4% concentrate on a dry matter basis. The HP (kcal/BW) was measured using 3 techniques, first using OP-HR, followed by the RC and CS methods. The HP did not differ among assessed techniques, averaging 162.7kcal/BW. The intercepts of the linear regressions (mean ± SE) were 64.82±25.515 (H: intercept=0; P=0.024), 33.77±13.418 (H: intercept=0), and 50.02±27.495 (H: intercept=0) for OP-HR versus RC, CS versus RC, and OP-HR versus CS, respectively. The slopes of the linear regressions were 0.59±0.153 (H: slope=1), 0.88±0.081 (H: slope=1), and 0.62±0.155 (H: slope=1) for OP-HR versus RC, CS versus RC, and OP-HR versus CS, respectively. The coefficients of determination were 0.52, 0.90, and 0.52 for OP-HR versus RC, CS versus RC, and OP-HR versus CS, respectively. The concordance correlation coefficients, 0.70 and 0.68, were moderate for OP-HR versus RC and OP-HR versus CS, respectively, but high, 0.90, for CS versus RC. The between-animal coefficient of variation was greater for the OP-HR method (16.6%) compared with RC (7.7%) or CS (6.7%). We conclude that there was an agreement among the HP measurements detected using the assessed methods and that OP-HR is able to predict HP in cattle with great accuracy but only moderate precision. Therefore, the OP-HR method may have limitations in terms of assessing HP in low numbers of replications due to greater between-animal coefficient of variation than either the RC or CS methods.
Topics: Abattoirs; Animal Feed; Animals; Cattle; Diet; Heart Rate; Male; Oxygen; Silage; Thermogenesis; Zea mays
PubMed: 27544858
DOI: 10.3168/jds.2016-11157 -
Revista Da Escola de Enfermagem Da U S P Sep 2019To evaluate cardiorespiratory alterations due to a single session of hyperbaric oxygen therapy. (Randomized Controlled Trial)
Randomized Controlled Trial
OBJECTIVE
To evaluate cardiorespiratory alterations due to a single session of hyperbaric oxygen therapy.
METHOD
Randomized study with patients: a control group and hyperbaric oxygen therapy. Evaluations occurred in the beginning, during, and after exposure to pure oxygen above atmosphere for 2 hours. Systemic blood pressure, peripheral oxygen saturation, pulse rate, lung volume and lung capacity, and maximal inspiratory and expiratory pressures were evaluated. Peripheral oxygen saturation, pulse rate, and systemic blood pressure were evaluated during the pressurizing in the first hour. Data were evaluated by means of ANOVA, Mann-Whitney, and independent t-test (p<0.05).
RESULTS
A total of 14 adult patients were evaluated. In the group under therapy (seven subjects), aged: 49.57±14.59 years, there was a decrease in the pulse rate of 16 beats per minute after 35 minutes of therapy (intragroup analysis), and the peripheral oxygen saturation was higher within the same period compared to the control group.
CONCLUSION
The hyperbaric oxygen therapy promotes cardiorespiratory alterations with the increase of the peripheral oxygen saturation and decrease of the pulse rate, without altering blood pressure levels and the strength, volumes, and respiratory capacities.
Topics: Adult; Aged; Blood Pressure; Female; Heart Rate; Humans; Hyperbaric Oxygenation; Male; Middle Aged; Oxygen
PubMed: 31508730
DOI: 10.1590/S1980-220X2017051503469 -
Sensors (Basel, Switzerland) Feb 2023Intervals of low-quality photoplethysmogram (PPG) signals might lead to significant inaccuracies in estimation of pulse arrival time (PAT) during polysomnography (PSG)...
Intervals of low-quality photoplethysmogram (PPG) signals might lead to significant inaccuracies in estimation of pulse arrival time (PAT) during polysomnography (PSG) studies. While PSG is considered to be a "gold standard" test for diagnosing obstructive sleep apnea (OSA), it also enables tracking apnea-related nocturnal blood pressure fluctuations correlated with PAT. Since the electrocardiogram (ECG) is recorded synchronously with the PPG during PSG, it makes sense to use the ECG signal for PPG signal-quality assessment. (1) Objective: to develop a PPG signal-quality assessment algorithm for robust PAT estimation, and investigate the influence of signal quality on PAT during various sleep stages and events such as OSA. (2) Approach: the proposed algorithm uses R and T waves from the ECG to determine approximate locations of PPG pulse onsets. The MESA database of 2055 PSG recordings was used for this study. (3) Results: the proportions of high-quality PPG were significantly lower in apnea-related oxygen desaturation (matched-pairs rc = 0.88 and rc = 0.97, compared to OSA and hypopnea, respectively, when < 0.001) and arousal (rc = 0.93 and rc = 0.98, when < 0.001) than in apnea events. The significantly large effect size of interquartile ranges of PAT distributions was between low- and high-quality PPG ( < 0.001, rc = 0.98), and regular and irregular pulse waves ( < 0.001, rc = 0.74), whereas a lower quality of the PPG signal was found to be associated with a higher interquartile range of PAT across all subjects. Suggested PPG signal quality-based PAT evaluation reduced deviations (e.g., rc = 0.97, rc = 0.97, rc = 0.99 in hypopnea, oxygen desaturation, and arousal stages, respectively, when < 0.001) and allowed obtaining statistically larger differences between different sleep stages and events. (4) Significance: the implemented algorithm has the potential to increase the robustness of PAT estimation in PSG studies related to nocturnal blood pressure monitoring.
Topics: Humans; Polysomnography; Photoplethysmography; Heart Rate; Sleep Apnea, Obstructive; Oxygen
PubMed: 36850820
DOI: 10.3390/s23042220 -
Brazilian Journal of Cardiovascular... Aug 2021This quasi-experimental study aimed to evaluate the impact of early and regular mobilization on vital signs and oxygen saturation in open-heart surgery patients.
INTRODUCTION
This quasi-experimental study aimed to evaluate the impact of early and regular mobilization on vital signs and oxygen saturation in open-heart surgery patients.
METHODS
The study universe comprised patients undergoing open-heart surgery in the cardiovascular intensive care unit of a heart center. The study sample consisted of patients who underwent open-heart surgery from November 2016 to April 2017, met the inclusion criteria, and voluntarily agreed to participate in the study. The study included 75 patients. Of these, 67 completed the mobilization program in two days, starting on the first postoperative day. Each patient was mobilized three times: twice on the first postoperative day and once on the second postoperative day. Vital signs and oxygen saturation for each patient were measured 10 minutes before and 20 minutes after each mobilization.
RESULTS
The difference between pulse and systolic blood pressure values measured before and after the first mobilization was statistically significant (P<0.05). In addition, the difference between the mean systolic blood pressure values before the first mobilization and after the third mobilization (123.43±14.09 mmHg and 117.94±14.05 mmHg, respectively) was statistically significant (P<0.05). The other parameters measured in relation to the mobilizations were in the normal range.
CONCLUSION
Early and frequent mobilization did not cause vital signs and oxygen saturation to deviate from normal limits in open-heart surgery patients.
Topics: Cardiac Surgical Procedures; Heart Rate; Humans; Intensive Care Units; Oxygen; Vital Signs
PubMed: 33355786
DOI: 10.21470/1678-9741-2019-0481 -
Annual International Conference of the... Nov 2021Intrapartum fetal well-being assessment relies on fetal heart rate (FHR) monitoring. Studies have shown that FHR monitoring has a high false-positive rate for detecting...
Intrapartum fetal well-being assessment relies on fetal heart rate (FHR) monitoring. Studies have shown that FHR monitoring has a high false-positive rate for detecting fetal hypoxia during labor and delivery. A transabdominal fetal pulse oximeter device that measures fetal oxygen saturation non-invasively through NIR light source and photodetectors could increase the accuracy of hypoxia detection. As light travels through both maternal and fetal tissue, photodetectors on the surface of mother's abdomen capture mixed signals comprising fetal and maternal information. The fetal information should be extracted first to enable fetal oxygen saturation calculation. A multi-detector fetal signal extraction method is presented in this paper where adaptive noise cancellation is applied to four mixed signals captured by four separate photodetectors placed at varying distances from the light source. As a result of adaptive noise cancellation, we obtain four separate FHR by peak detection. Weighting, outlier rejection and averaging are applied to these four fetal heart rates and a mean FHR is reported. The method is evaluated in utero on data collected from hypoxic lamb model. Ground truth for FHR is measured through hemodynamics. The results showed that using multi-detector fetal signal extraction gave up to 18.56% lower root-mean-square FHR error, and up to 57.87% lower maximum absolute FHR error compared to single-detector fetal signal extraction.
Topics: Animals; Female; Fetal Hypoxia; Heart Rate, Fetal; Oximetry; Oxygen; Oxygen Saturation; Pregnancy; Sheep
PubMed: 34891473
DOI: 10.1109/EMBC46164.2021.9630946 -
Open Heart Nov 2023Peak oxygen pulse (Opulse=oxygen consumption/heart rate) is calculated by the product of stroke volume (SV) and oxygen extraction. It has been shown to be reduced in...
BACKGROUND
Peak oxygen pulse (Opulse=oxygen consumption/heart rate) is calculated by the product of stroke volume (SV) and oxygen extraction. It has been shown to be reduced in patients with a Fontan circulation. However, in the Fontan population, it may be a poor marker of SV. We propose that the slope of the O pulse curve may be more reflective of SV during exercise.
METHODS
We analysed cardiopulmonary exercise test data in 22 subjects with a Fontan circulation (cohort A) and examined the association between peak SV during exercise (aortic flow measured on exercise cardiac MRI), and O pulse parameters (absolute O pulse and O pulse slopes up to anaerobic threshold (AT) and peak exercise). In a separate Fontan cohort (cohort B, n=131), associations between clinical characteristics and O pulse kinetics were examined.
RESULTS
In cohort A, peak aortic flow was moderately and significantly associated with Opulseslope (r=0.47, p=0.02). However, neither absolute Opulse nor Opulse was significantly associated with peak aortic flow. In cohort B, Opulseslope and Opulseslope were not significantly associated with clinical parameters, apart from a weak association with forced vital capacity.
CONCLUSION
The slope of the O pulse curve to peak exercise may be more reflective of peak SV in the Fontan population than a single peak O pulse value.
Topics: Humans; Fontan Procedure; Stroke Volume; Heart Rate; Exercise Test; Oxygen
PubMed: 37935560
DOI: 10.1136/openhrt-2023-002324 -
Journal of Applied Physiology... Dec 2017Cerebral vasodilation and increased cerebral oxygen extraction help maintain cerebral oxygen uptake in the face of hypoxemia. This study examined cerebrovascular...
Cerebral vasodilation and increased cerebral oxygen extraction help maintain cerebral oxygen uptake in the face of hypoxemia. This study examined cerebrovascular responses to intermittent hypoxemia in eight healthy men breathing 10% O for 5 cycles, each 6 min, interspersed with 4 min of room air breathing. Hypoxia exposures raised heart rate ( P < 0.01) without altering arterial pressure, and increased ventilation ( P < 0.01) by expanding tidal volume. Arterial oxygen saturation ([Formula: see text]) and cerebral tissue oxygenation ([Formula: see text]) fell ( P < 0.01) less appreciably in the first bout (from 97.0 ± 0.3% and 72.8 ± 1.6% to 75.5 ± 0.9% and 54.5 ± 0.9%, respectively) than the fifth bout (from 94.9 ± 0.4% and 70.8 ± 1.0% to 66.7 ± 2.3% and 49.2 ± 1.5%, respectively). Flow velocity in the middle cerebral artery ( V) and cerebrovascular conductance increased in a sigmoid fashion with decreases in [Formula: see text] and [Formula: see text]. These stimulus-response curves shifted leftward and upward from the first to the fifth hypoxia bouts; thus, the centering points fell from 79.2 ± 1.4 to 74.6 ± 1.1% ( P = 0.01) and from 59.8 ± 1.0 to 56.6 ± 0.3% ( P = 0.002), and the minimum V increased from 54.0 ± 0.5 to 57.2 ± 0.5 cm/s ( P = 0.0001) and from 53.9 ± 0.5 to 57.1 ± 0.3 cm/s ( P = 0.0001) for the [Formula: see text]- V and [Formula: see text]- V curves, respectively. Cerebral oxygen extraction increased from prehypoxia 0.22 ± 0.01 to 0.25 ± 0.02 in minute 6 of the first hypoxia bout, and remained elevated between 0.25 ± 0.01 and 0.27 ± 0.01 throughout the fifth hypoxia bout. These results demonstrate that cerebral vasodilation combined with enhanced cerebral oxygen extraction fully compensated for decreased oxygen content during acute, cyclic hypoxemia. NEW & NOTEWORTHY Five bouts of 6-min intermittent hypoxia (IH) exposures to 10% O progressively reduce arterial oxygen saturation ([Formula: see text]) to 67% without causing discomfort or distress. Cerebrovascular responses to hypoxemia are dynamically reset over the course of a single IH session, such that threshold and saturation for cerebral vasodilations occurred at lower [Formula: see text] and cerebral tissue oxygenation ([Formula: see text]) during the fifth vs. first hypoxia bouts. Cerebral oxygen extraction is augmented during acute hypoxemia, which compensates for decreased arterial O content.
Topics: Adult; Cerebrovascular Circulation; Heart Rate; Humans; Hypoxia; Male; Oxygen; Oxygen Consumption; Pulmonary Gas Exchange; Tidal Volume; Vasodilation
PubMed: 29074711
DOI: 10.1152/japplphysiol.00647.2017