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Critical Care (London, England) Feb 2018In clinical practice, oxygen is generally administered to patients with the intention of increasing oxygen delivery. Supplemental oxygen may, however, cause arterial... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
In clinical practice, oxygen is generally administered to patients with the intention of increasing oxygen delivery. Supplemental oxygen may, however, cause arterial hyperoxia, which is associated with hemodynamic alterations. We performed a systematic review and meta-analysis of the literature to determine the effect of hyperoxia on central hemodynamics and oxygen delivery in healthy volunteers and cardiovascular-compromised patients.
METHODS
PubMed and EMBASE were searched up to March 2017. Studies with adult humans investigating changes in central hemodynamics or oxygen delivery induced by acute normobaric hyperoxia were included. Studies focusing on lung, retinal, or brain parameters were not included. We extracted subject and oxygen exposure characteristics, indexed and unindexed values for heart rate, stroke volume, cardiac output, mean arterial pressure (MAP), systemic vascular resistance, and oxygen delivery during normoxia and hyperoxia. For quantitative synthesis of the data, a random-effects ratio of means (RoM) model was used.
RESULTS
We identified 33 studies with 42 datasets. Study categories included healthy volunteers (n = 22 datasets), patients with coronary artery disease (CAD; n = 6), heart failure (HF; n = 6), coronary artery bypass graft (CABG; n = 3) and sepsis (n = 5). Hyperoxia (arterial oxygen tension of 234-617 mmHg) reduced cardiac output (CO) by 10-15% in both healthy volunteers (-10.2%, 95% confidence interval (CI) -12.9% to -7.3%) and CAD (-9.6%, 95% CI -12.3% to -6.9%) or HF patients (-15.2%, 95% CI -21.7% to -8.2%). No significant changes in cardiac output were seen in CABG or septic patients (-3%). Systemic vascular resistance increased remarkably in patients with heart failure (24.6%, 95% CI 19.3% to 30.1%). In healthy volunteers, and those with CAD and CABG, the effect was smaller (11-16%) and was virtually absent in patients with sepsis (4.3%, 95% CI -3.2% to 12.3%). No notable effect on MAP was found in any group (2-3%). Oxygen delivery was not altered by hyperoxia. Considerable heterogeneity existed between study results, likely due to methodological differences.
CONCLUSIONS
Hyperoxia may considerably decrease cardiac output and increase systemic vascular resistance, but effects differ between patient categories. Heart failure patients were the most sensitive while no hemodynamic effects were seen in septic patients. There is currently no evidence supporting the notion that oxygen supplementation increases oxygen delivery.
Topics: Blood Gas Analysis; Blood Pressure; Cardiac Output; Heart Rate; Hemodynamics; Humans; Hyperoxia; Oxygen; Vascular Resistance
PubMed: 29477145
DOI: 10.1186/s13054-018-1968-2 -
American Journal of Physiology. Heart... Nov 2022We sought to determine the effects of prolonged moderate hypobaric hypoxia (HH) on cardiac baroreflex sensitivity (cBRS) in young women and whether these effects are a...
We sought to determine the effects of prolonged moderate hypobaric hypoxia (HH) on cardiac baroreflex sensitivity (cBRS) in young women and whether these effects are a consequence of the reduced arterial oxygen (O) tension and/or increased pulmonary ventilation in HH. We hypothesized that HH would reduce cBRS and that this effect would be counteracted by acute restoration of the inspiratory partial pressure of O ([Formula: see text]) and/or voluntary attenuation of pulmonary ventilation. Twelve healthy women (24.0 ± 4.2 yr) were studied before () and twice during a sojourn in a hypobaric chamber (∼8 h, ; 4 days, ) where barometric pressure corresponded to ∼3,500-m altitude. Minute ventilation (V̇e; pneumotachometer), heart rate (electrocardiogram), and arterial pressure (finger volume clamp method) were recorded. cBRS was calculated using transfer function analysis between systolic pressure and RR interval. Assessments were made during ) spontaneous breathing and (in HH only), ) controlled breathing (reducing V̇e by ∼1 to 2 L/min), and ) breathing a hyperoxic gas mixture that normalized [Formula: see text]. During spontaneous breathing, HH decreased cBRS (12.5 ± 7.1, 8.9 ± 4.4, and 7.4 ± 3.0 ms/mmHg on , , and , respectively; = 0.018). The normalization of [Formula: see text] increased cBRS (10.6 ± 3.3 and 10.7 ± 6.1 ms/mmHg on and ) in HH compared with values observed during spontaneous breathing ( < 0.001), whereas controlled breathing had no effect on cBRS ( = 0.708). These findings indicate that ongoing arterial chemoreflex activation by the reduced arterial O tension, independently of the hypoxic ventilatory response, reduces cBRS in young women exposed to extended HH. We examined the effects of prolonged hypobaric hypoxia (corresponding to ∼3,500-m altitude) on cardiac baroreflex sensitivity (cBRS) in young women and investigated underlying mechanisms. We found that cBRS was reduced in hypoxia and that this reduction was attenuated by acute restoration of inspiratory oxygen partial pressure but not by volitional restraint of pulmonary ventilation. These findings help to elucidate the role of arterial chemoreflex mechanisms in the control of cBRS during hypobaric hypoxia in young women.
Topics: Humans; Female; Baroreflex; Hypoxia; Altitude; Altitude Sickness; Oxygen; Heart Rate
PubMed: 36240437
DOI: 10.1152/ajpheart.00452.2022 -
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 -
International Journal of Environmental... Sep 2022Cardiovascular capacity, expressed as maximal oxygen uptake (VO), is a strong predictor of health and fitness and is considered a key measure of physiological function...
BACKGROUND
Cardiovascular capacity, expressed as maximal oxygen uptake (VO), is a strong predictor of health and fitness and is considered a key measure of physiological function in the healthy adult population. The purpose of this study was to validate a specific step test (StepTest4all) as an adequate procedure to estimate cardiovascular capacity in young adults.
METHODS
The sample was composed of 56 participants, including 19 women (aged 21.05 ± 2.39 years, body mass = 57.50 ± 6.64 kg, height = 1.62 ± 0.05 m, body mass index = 22.00 ± 2.92 kg/m) and 37 men (aged 22.05 ± 3.14 years, body mass = 72.50 ± 7.73 kg, height = 1.76 ± 0.07 m, body mass index = 23.34 ± 2.17 kg/m). Participants were included in one of the following groups: (i) the group used to predict the VO, and (ii) the group used to validate the prediction model. All participants performed the StepTest4all protocol. The step height and the intensity of the effort was determined individually. Heart rate and oxygen uptake were measured continuously during rest, effort, and recovery phases. The validation process included the following three stages: (i) mean data comparison, (ii) simple linear regression, and (iii) Bland-Altman analysis.
RESULTS
The linear regression retained, as significant predictors of the VO, sex ( < 0.001) and heart rate recovery for one minute ( = 0.003). The prediction equation revealed a high relationship between measurements (R = 63.0%, SEE = 5.58). The validation procedure revealed non-significant differences ( > 0.05) between the measured and estimated maximal oxygen uptake, high relationship (R = 63.3%), and high agreement with Bland-Altman plots. Thus, VO can be estimated with the formula: VO = 22 + 0.3 · (HRR) + 12 · (sex), where HRR is the magnitude of the HR decrease (bpm) in one minute immediately after the step was stopped, and sex: men = 1, women = 0.
CONCLUSIONS
The StepTest4all is an adequate procedure to estimate cardiovascular capacity, expressed as VO, in young adults. In addition, it is possible to determine the qualitative level of cardiovascular capacity from the heart rate recovery for one minute, more specifically, poor: <20, moderate: 20 to 34, good: 35 to 49, and excellent: ≥50. This procedure has the benefit of being simple to apply and can be used by everyone, even at home, without specialist supervision.
Topics: Exercise; Exercise Test; Female; Heart Rate; Humans; Male; Oxygen; Oxygen Consumption; Young Adult
PubMed: 36141547
DOI: 10.3390/ijerph191811274 -
Philosophical Transactions of the Royal... Aug 2021In the 1940s, Scholander and Irving revealed fundamental physiological responses to forced diving of marine mammals and birds, setting the stage for the study of diving... (Review)
Review
In the 1940s, Scholander and Irving revealed fundamental physiological responses to forced diving of marine mammals and birds, setting the stage for the study of diving physiology. Since then, diving physiology research has moved from the laboratory to the field. Modern biologging, with the development of microprocessor technology, recorder memory capacity and battery life, has advanced and expanded investigations of the diving physiology of marine mammals and birds. This review describes a brief history of the start of field diving physiology investigations, including the invention of the time depth recorder, and then tracks the use of biologging studies in four key diving physiology topics: heart rate, blood flow, body temperature and oxygen store management. Investigations of diving heart rates in cetaceans and O store management in diving emperor penguins are highlighted to emphasize the value of diving physiology biologging research. The review concludes with current challenges, remaining diving physiology questions and what technologies are needed to advance the field. This article is part of the theme issue 'Measuring physiology in free-living animals (Part I)'.
Topics: Animals; Aquatic Organisms; Birds; Blood Circulation; Body Temperature; Diving; Heart Rate; Mammals; Oxygen
PubMed: 34121464
DOI: 10.1098/rstb.2020.0211 -
Einstein (Sao Paulo, Brazil) 2023The World Health Organization and Centers for Disease Control and Prevention recommend the use of face masks in public. This study aimed to evaluate the effects of face...
OBJECTIVE
The World Health Organization and Centers for Disease Control and Prevention recommend the use of face masks in public. This study aimed to evaluate the effects of face masks on pulse rate and partial blood oxygen saturation in patients without cardiorespiratory disorders.
METHODS
A total of 150 volunteers of both sexes were divided into three groups (n=50) according to age (children, young adults, and older adults). The partial blood oxygen saturation and pulse rate were measured for each volunteer using a digital oximeter while wearing a facial mask and remaining at rest. The masks were removed for two minutes, and partial blood oxygen saturation and pulse rate were remeasured. The materials and types of masks used were recorded. The t -test for paired samples was used to compare the mean values obtained before and after removing the masks.
RESULTS
The most frequently used mask was a two-layered cloth (64.7%). A decrease in pulse rate was observed after removing the face mask in males, particularly in children (p=0.006) and young adults (p=0.034). Partial blood oxygen saturation levels increased in young adult males after mask removal (p=0.01).
CONCLUSION
The two-layer cotton tissue face masks are associated with a higher pulse rate and reduced arterial blood oxygen saturation without associated clinical disorders, mainly in adult men with a lower tolerance to breathing and ear discomfort.
Topics: Male; Child; Female; Young Adult; Humans; Aged; Masks; Heart Rate; Lung; Oxygen
PubMed: 37970950
DOI: 10.31744/einstein_journal/2023AO0349 -
Journal of Biomedical Optics Jul 2019To refine animal research, vital signs, activity, stress, and pain must be monitored. In chronic studies, some measures can be assessed using telemetry sensors. Although... (Review)
Review
To refine animal research, vital signs, activity, stress, and pain must be monitored. In chronic studies, some measures can be assessed using telemetry sensors. Although this methodology provides high-precision data, an initial surgery for device implantation is necessary, potentially leading to stress, wound infections, and restriction of motion. Recently, camera systems have been adapted for animal research. We give an overview of parameters that can be assessed using imaging in the visible, near-infrared, and thermal spectrum of light. It focuses on heart activity, respiration, oxygen saturation, and motion, as well as on wound analysis. For each parameter, we offer recommendations on the minimum technical requirements of appropriate systems, regions of interest, and light conditions, among others. In general, these systems demonstrate great performance. For heart and respiratory rate, the error was <4 beats / min and 5 breaths/min. Furthermore, the systems are capable of tracking animals during different behavioral tasks. Finally, studies indicate that inhomogeneous temperature distribution around wounds might be an indicator of (pending) infections. In sum, camera-based techniques have several applications in animal research. As vital parameters are currently only assessed in sedated animals, the next step should be the integration of these modalities in home-cage monitoring.
Topics: Animals; Heart Rate; Laboratory Animal Science; Mice; Monitoring, Physiologic; Movement; Optical Imaging; Oxygen; Rats; Thermography; Video Recording; Wound Healing
PubMed: 31286726
DOI: 10.1117/1.JBO.24.7.070601 -
The Journal of Clinical Pediatric... 2018We aimed to examine if changes in oxygen saturation and pulse rate of pediatric patients during conscious sedation with midazolam and nitrous oxide are associated with...
OBJECTIVE
We aimed to examine if changes in oxygen saturation and pulse rate of pediatric patients during conscious sedation with midazolam and nitrous oxide are associated with child's behavior, midazolam dose, the type and duration of the treatment and demographic parameters.
STUDY DESIGN
This study was a retrospective chart review of consecutive pediatric patients, aged 2.5-12.5 years, who had undergone conscious sedation for dental treatment with oral midazolam (with or without nitrous oxide) between January 2011 and September 2015 at the Department of Pediatric Dentistry of Tel Aviv University. Oral midazolam was administered according to the patients' weight, either at 0.4 mg/kg, 0.5 mg/kg or at a maximum dose of 10 mg. In all cases pulse rate and oxygen saturation were monitored every 15 minutes during treatment, Results: 147 sedation sessions (82 of females and 65 of males) were included in the study. Sedation was successful in 80% of cases. Children with poor behavior scores had statistically significant different mean saturation levels, albeit within normal range, during the treatment (p<0.012) as well as a clinically significant higher mean pulse rate (p=0.0001), compared to children with good or excellent behavior scores. Treatment duration, the type of dental procedure or the patients' weight were not correlated with the change in oxygen saturation or pulse rate during the treatment.
CONCLUSIONS
Poor behavior of pediatric patients does not affect oxygen saturation, but it increases the pulse rate of children under sedation with midazolam and nitrous oxide.
Topics: Administration, Oral; Anesthesia, Dental; Anesthetics, Inhalation; Child; Child Behavior; Child, Preschool; Conscious Sedation; Female; Heart Rate; Humans; Hypnotics and Sedatives; Male; Midazolam; Nitrous Oxide; Oxygen; Retrospective Studies
PubMed: 30085872
DOI: 10.17796/1053-4625-42.6.11 -
Sensors (Basel, Switzerland) Jan 2023Modern cardiac pacemakers are equipped with a function that allows the heart rate to adapt to the current needs of the patient in situations of increased demand related... (Review)
Review
Modern cardiac pacemakers are equipped with a function that allows the heart rate to adapt to the current needs of the patient in situations of increased demand related to exercise and stress ("rate-response" function). This function may be based on a variety of mechanisms, such as a built-in accelerometer responding to increased chest movement or algorithms sensing metabolic demand for oxygen, analysis of intrathoracic impedance, and analysis of the heart rhythm (Q-T interval). The latest technologies in the field of rate-response functionality relate to the use of an accelerometer in leadless endocavitary pacemakers; in these devices, the accelerometer enables mapping of the mechanical wave of the heart's work cycle, enabling the pacemaker to correctly sense native impulses and stimulate the ventricles in synchrony with the cycles of atria and heart valves. Another modern system for synchronizing pacing rate with the patient's real-time needs requires a closed-loop system that continuously monitors changes in the dynamics of heart contractions. This article discusses the technical details of various solutions for detecting and responding to situations related to increased oxygen demand (e.g., exercise or stress) in implantable pacemakers, and reviews the results of clinical trials regarding the use of these algorithms.
Topics: Humans; Pacemaker, Artificial; Heart Rate; Heart Atria; Heart Ventricles; Oxygen
PubMed: 36772467
DOI: 10.3390/s23031427 -
Computer Methods and Programs in... Jun 2022Consumer-level cameras have provided an advantage of designing cost-effective, non-contact physiological parameters estimation approaches which is not possible with gold... (Review)
Review
BACKGROUND
Consumer-level cameras have provided an advantage of designing cost-effective, non-contact physiological parameters estimation approaches which is not possible with gold standard estimation techniques. This encourages the development of non-contact estimation methods using camera technology. Therefore, this work aims to present a systematic review summarizing the currently existing face-based non-contact methods along with their performance.
METHODS
This review includes all heart rate (HR) and oxygen saturation (SpO2) studies published in journals and a few reputed conferences, which have compared the proposed estimation methods with one or more standard reference devices. The articles were collected from the following research databases: Institute of Electrical and Electronics Engineers (IEEE), PubMed, Web of Science (WoS), Science Direct, and Association of Computer Machinery (ACM) digital library. All database searches were completed on May 20, 2021. Each study was assessed using a finite set of identified factors for reporting bias.
RESULTS
Out of 332 identified studies, 32 studies were selected for the final review. Additionally, 18 studies were included by thoroughly checking these studies. 3 out of 50 (6%) studies were performed in clinical conditions, while the remaining studies were carried out on a healthy population. 42 out of 50 (84%) studies have estimated HR, while 5/50 (10%) studies have measured SpO only. The remaining three studies have estimated both parameters. The majority of the studies have used 1-3 min videos for estimation. Among the estimation methods, Deep Learning and Independent component analysis (ICA) were used by 11/42 (26.19%) and 9/42 (21.42%) studies, respectively. According to the Bland-Altman analysis, only 8/45 (17.77%) HR studies achieved the clinically accepted error limits whereas, for SpO, 4/5 (80%) studies have matched the industry standards (±3%).
DISCUSSION
Deep Learning and ICA have been predominantly used for HR estimations. Among deep learning estimation methods, convolutional neural networks have been employed till date due to their good generalization ability. Most non-contact HR estimation methods need significant improvements to implement these methods in a clinical environment. Furthermore, these methods need to be tested on the subjects suffering from any related disease. SpO estimation studies are challenging and need to be tested by conducting hypoxemic events. The authors would encourage reporting the detailed information about the study population, the use of longer videos, and appropriate performance metrics and testing under abnormal HR and SpO ranges for future estimation studies.
Topics: Face; Heart Rate; Humans; Oxygen Saturation
PubMed: 35390724
DOI: 10.1016/j.cmpb.2022.106771