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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 -
Journal of Clinical Medicine Jan 2024Heart rate variability (HRV) is a reliable and convenient method to assess autonomic function. Cross-sectional studies have established a link between HRV and cognition.... (Review)
Review
BACKGROUND
Heart rate variability (HRV) is a reliable and convenient method to assess autonomic function. Cross-sectional studies have established a link between HRV and cognition. Longitudinal studies are an emerging area of research with important clinical implications in terms of the predictive value of HRV for future cognition and in terms of the potential causal relationship between HRV and cognition. However, they have not yet been the objective of a systematic review. Therefore, the aim of this systematic review was to investigate the association between HRV and cognition in longitudinal studies.
METHODS
The review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The Embase, PsycINFO and PubMed databases were searched from the earliest available date to 26 June 2023. Studies were included if they involved adult human subjects and evaluated the longitudinal association between HRV and cognition. The risk of bias was assessed with the Newcastle-Ottawa Scale for Cohort Studies. The results were presented narratively.
RESULTS
Of 14,359 records screened, 12 studies were included in this systematic review, with a total of 24,390 participants. Two thirds of the studies were published from 2020 onwards. All studies found a longitudinal relationship between HRV and cognition. There was a consistent association between higher parasympathetic nervous system (PNS) activity and better cognition, and some association between higher sympathetic nervous system activity and worse cognition. Also, higher PNS activity persistently predicted better executive functioning, while data on episodic memory and language were more scant and/or controversial.
CONCLUSIONS
Our results support the role of HRV as a biomarker of future cognition and, potentially, as a therapeutic target to improve cognition. They will need confirmation by further, more comprehensive studies also including unequivocal non-HRV sympathetic measures and meta-analyses.
PubMed: 38202287
DOI: 10.3390/jcm13010280 -
The Cochrane Database of Systematic... Dec 2016Many antihypertensive agents exist today for the treatment of primary hypertension (systolic blood pressure ≥ 140 mmHg or diastolic blood pressure ≥ 90 mmHg, or... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Many antihypertensive agents exist today for the treatment of primary hypertension (systolic blood pressure ≥ 140 mmHg or diastolic blood pressure ≥ 90 mmHg, or both). Randomised controlled trials (RCTs) have been carried out to investigate the evidence for these agents. There is, for example, strong RCT evidence that thiazides reduce mortality and morbidity. Some of those trials used reserpine as a second-line therapy. However, the dose-related blood pressure reduction with this agent is not known.
OBJECTIVES
The primary objective of this review was to quantify the dose-related efficacy of reserpine versus placebo or no treatment in reducing systolic blood pressure (SBP) or diastolic blood pressure (DBP), or both.We also aimed to evaluate the dose-related effects of reserpine on mean arterial blood pressure (MAP) and heart rate (HR), as well as the dose-related effects on withdrawals due to adverse events.
SEARCH METHODS
We searched the Cochrane Hypertension Group Specialised Register (January 1946 to October 2016), CENTRAL (2016, Issue 10), MEDLINE (January 1946 to October 2016), Embase (January 1974 to October 2016), and ClinicalTrials.gov (all dates to October 2016). We also traced citations in the reference sections of the retrieved studies.
SELECTION CRITERIA
Included studies were truly randomised controlled trials (RCTs) comparing reserpine monotherapy to placebo or no treatment in participants with primary hypertension.
DATA COLLECTION AND ANALYSIS
We assessed methods of randomisation and concealment. We extracted and analysed data on blood pressure reduction, heart rate, and withdrawal due to adverse effects.
MAIN RESULTS
We found four RCTs (with a total of 237 participants) that met the inclusion criteria, none of which we found through the 2016 update search. The overall pooled effect demonstrates a statistically significant systolic blood pressure (SBP) reduction in participants taking reserpine compared with placebo (weighted mean difference (WMD) -7.92, 95% confidence interval (CI) -14.05 to -1.78). Because of significant heterogeneity across the trials, a significant effect in diastolic blood pressure (DBP), mean arterial pressure (MAP), and heart rate (HR) could not be found. A dose of reserpine 0.5 mg/day or greater achieved the SBP effects. However, we could not determine the dose-response pattern because of the small number of trials. We did not combine data from the trial that investigated Rauwiloid against placebo with reserpine data from the remaining three trials. This is because Rauwiloid is a different alkaloid extract of the plant Rauwolfia serpentina, and the dose used is not comparable to reserpine. None of the included trials reported withdrawals due to adverse effects.
AUTHORS' CONCLUSIONS
Reserpine is effective in reducing SBP roughly to the same degree as other first-line antihypertensive drugs. However, we could not make definite conclusions regarding the dose-response pattern because of the small number of included trials. More RCTs are needed to assess the effects of reserpine on blood pressure and to determine the dose-related safety profile before the role of this drug in the treatment of primary hypertension can be established.
Topics: Antihypertensive Agents; Blood Pressure; Heart Rate; Humans; Hypertension; Randomized Controlled Trials as Topic; Rauwolfia; Reserpine
PubMed: 27997978
DOI: 10.1002/14651858.CD007655.pub3 -
Cortex; a Journal Devoted To the Study... Oct 2022The recent focus on the bidirectional heart-brain interactions in psychoneurophysiological research has led to a variety of findings suggesting vagal activity is... (Meta-Analysis)
Meta-Analysis Review
The recent focus on the bidirectional heart-brain interactions in psychoneurophysiological research has led to a variety of findings suggesting vagal activity is associated with cognition and, possibly, specifically with executive functioning. This systematic review and meta-analysis aimed to provide a better understanding of the association between vagally-mediated heart rate variability (HRV) and executive functioning. We included 13 correlational studies. We found a small positive association between vagally-mediated HRV and executive functioning (r = .19, 95% CI .15 to .23, p < .0001) using a quantitative synthesis of existing studies with random-effect models. Conducting meta-regression analyses, we found that vagally-mediated HRV predicts cognitive inhibition and cognitive flexibility more than working memory. In addition to the specific executive function measured, this relationship is moderated by the HRV measurement used, and age. After proposing a theoretical interpretation of the results, we emphasized the need for further research in light of the methodological issues identified in the included studies, and we outline several aspects to consider in future studies.
Topics: Brain; Executive Function; Heart Rate; Humans; Vagus Nerve
PubMed: 36030561
DOI: 10.1016/j.cortex.2022.07.008 -
The Cochrane Database of Systematic... Nov 2017Atrial fibrillation is the commonest cardiac dysrhythmia. It is associated with significant morbidity and mortality. There are two approaches to the management of atrial... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Atrial fibrillation is the commonest cardiac dysrhythmia. It is associated with significant morbidity and mortality. There are two approaches to the management of atrial fibrillation: controlling the ventricular rate or converting to sinus rhythm in the expectation that this would abolish its adverse effects.
OBJECTIVES
To assess the effects of pharmacological cardioversion of atrial fibrillation in adults on the annual risk of stroke, peripheral embolism, and mortality.
SEARCH METHODS
We searched the Cochrane Controlled Trials Register (Issue 3, 2002), MEDLINE (2000 to 2002), EMBASE (1998 to 2002), CINAHL (1982 to 2002), Web of Science (1981 to 2002). We hand searched the following journals: Circulation (1997 to 2002), Heart (1997 to 2002), European Heart Journal (1997-2002), Journal of the American College of Cardiology (1997-2002) and selected abstracts published on the web site of the North American Society of Pacing and Electrophysiology (2001, 2002).
SELECTION CRITERIA
Randomised controlled trials or controlled clinical trials of pharmacological cardioversion versus rate control in adults (>18 years) with acute, paroxysmal or sustained atrial fibrillation or atrial flutter, of any duration and of any aetiology.
DATA COLLECTION AND ANALYSIS
One reviewer applied the inclusion criteria and extracted the data. Trial quality was assessed and the data were entered into RevMan.
MAIN RESULTS
We identified two completed studies AFFIRM (n=4060) and PIAF (n=252). We found no difference in mortality between rhythm control and rate control relative risk 1.14 (95% confidence interval 1.00 to 1.31).Both studies show significantly higher rates of hospitalisation and adverse events in the rhythm control group and no difference in quality of life between the two treatment groups.In AFFIRM there was a similar incidence of ischaemic stroke, bleeding and systemic embolism in the two groups. Certain malignant dysrhythmias were significantly more likely to occur in the rhythm control group. There were similar scores of cognitive assessment.In PIAF, cardioverted patients enjoyed an improved exercise tolerance but there was no overall benefit in terms of symptom control or quality of life.
AUTHORS' CONCLUSIONS
There is no evidence that pharmacological cardioversion of atrial fibrillation to sinus rhythm is superior to rate control. Rhythm control is associated with more adverse effects and increased hospitalisation. It does not reduce the risk of stroke. The conclusions cannot be generalised to all people with atrial fibrillation. Most of the patients included in these studies were relatively older (>60 years) with significant cardiovascular risk factors.
Topics: Adult; Aged; Anti-Arrhythmia Agents; Atrial Fibrillation; Atrial Flutter; Heart Rate; Humans; Middle Aged; Randomized Controlled Trials as Topic
PubMed: 29140557
DOI: 10.1002/14651858.CD003713.pub3 -
The Cochrane Database of Systematic... Nov 2015Retained placenta affects 0.5% to 3% of women following delivery, with considerable morbidity if left untreated. Use of nitroglycerin (NTG), either alone or in... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Retained placenta affects 0.5% to 3% of women following delivery, with considerable morbidity if left untreated. Use of nitroglycerin (NTG), either alone or in combination with uterotonics, may be of value to minimise the need for manual removal of the placenta in theatre under anaesthesia.
OBJECTIVES
To evaluate the benefits and harms of NTG as a tocolytic, either alone or in addition to uterotonics, in the management of retained placenta.
SEARCH METHODS
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (14 January 2015), reference lists of retrieved studies and contacted experts in the field.
SELECTION CRITERIA
Any adequately randomised controlled trial (RCT) comparing the use of NTG, either alone or in combination with uterotonics, with no intervention or with other interventions in the management of retained placenta. All women having a vaginal delivery with a retained placenta, regardless of the management of the third stage of labour (expectant or active). We included all trials with haemodynamically stable women in whom the placenta was not delivered at least within 15 minutes after delivery of the baby.
DATA COLLECTION AND ANALYSIS
Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy.
MAIN RESULTS
We included three randomised controlled trials (RCTs) with 175 women. The three published RCTs compared NTG alone versus placebo. The detachment status of retained placenta was unknown in all three RCTs. Collectively, among the three included trials, two were judged to be at low risk of bias and the third trial was judged to be at high risk of bias for two domains: incomplete outcome data and selective reporting. The three trials reported seven out of 23 of the review's pre-specified outcomes.The primary outcome "manual removal of the placenta" was reported in all three studies. No differences were seen between NTG and placebo for manual removal of the placenta (average risk ratio (RR) 0.83, 95% confidence interval (CI) 0.47 to 1.46; women = 175; I² = 81%). A random-effects model was used because of evidence of substantial heterogeneity in the analysis. There were also no differences between groups for risk of severe postpartum haemorrhage (RR 0.93, 95% CI 0.62 to 1.39; women = 150; studies = two; I² = 0%). Blood transfusion was only reported in one study (40 women) and again there was no difference between groups (RR 1.00, 95% CI 0.07 to 14.90; women = 40; I² = 0%). Mean blood loss (mL) was reported in the three studies and no differences were observed (mean difference (MD) -115.31, 95% CI -306.25 to 75.63; women = 169; I² = 83%). Nitroglycerin administration was not associated with an increase in headaches (RR 1.09, 95% CI 0.80 to 1.47; women = 174; studies = three; I² = 0%). However, nitroglycerin administration was associated with a significant, though mild, decrease in systolic and diastolic blood pressure and a significant increase in pulse rate (MD -3.75, 95% CI -7.47 to -0.03) for systolic blood pressure, and (MD 6.00, 95% CI 3.07 to 8.93) for pulse rate (beats per minute) respectively (reported by only one study including 24 participants). Maternal mortality and addition of therapeutic uterotonics were not reported in any study.
AUTHORS' CONCLUSIONS
In cases of retained placenta, currently available data showed that the use of NTG alone did not reduce the need for manual removal of placenta. This intervention did not increase the incidence of severe postpartum haemorrhage nor the need for blood transfusion. Haemodynamically, NTG had a significant though mild effect on both pulse rate and blood pressure.
Topics: Administration, Sublingual; Female; Headache; Humans; Nitroglycerin; Oxytocics; Oxytocin; Placenta, Retained; Postpartum Hemorrhage; Pregnancy; Randomized Controlled Trials as Topic
PubMed: 26558329
DOI: 10.1002/14651858.CD007708.pub3 -
Sports Medicine (Auckland, N.Z.) Jul 2023Heat adaptation regimes are used to prepare athletes for exercise in hot conditions to limit a decrement in exercise performance. However, the heat adaptation literature... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Heat adaptation regimes are used to prepare athletes for exercise in hot conditions to limit a decrement in exercise performance. However, the heat adaptation literature mostly focuses on males, and consequently, current heat adaptation guidelines may not be optimal for females when accounting for the biological and phenotypical differences between sexes.
OBJECTIVES
We aimed to examine: (1) the effects of heat adaptation on physiological adaptations in females; (2) the impact of heat adaptation on performance test outcomes in the heat; and (3) the impact of various moderators, including duration (minutes and/or days), total heat dose (°Cmin), exercise intensity (kcalmin), total energy expended (kcal), frequency of heat exposures and training status on the physiological adaptations in the heat.
METHODS
SPORTDiscus, MEDLINE Complete and Embase databases were searched to December 2022. Random-effects meta-analyses for resting and exercise core temperature, skin temperature, heart rate, sweat rate, plasma volume and performance tests in the heat were completed using Stata Statistical Software: Release 17. Sub-group meta-analyses were performed to explore the effect of duration, total heat dose, exercise intensity, total energy expended, frequency of heat exposure and training status on resting and exercise core temperature, skin temperature, heart rate and sweat rate. An explorative meta-regression was conducted to determine the effects of physiological adaptations on performance test outcomes in the heat following heat adaptation.
RESULTS
Thirty studies were included in the systematic review; 22 studies were meta-analysed. After heat adaptation, a reduction in resting core temperature (effect size [ES] = - 0.45; 95% confidence interval [CI] - 0.69, - 0.22; p < 0.001), exercise core temperature (ES = - 0.81; 95% CI - 1.01, - 0.60; p < 0.001), skin temperature (ES = - 0.64; 95% CI - 0.79, - 0.48; p < 0.001), heart rate (ES = - 0.60; 95% CI - 0.74, - 0.45; p < 0.001) and an increase in sweat rate (ES = 0.53; 95% CI 0.21, 0.85; p = 0.001) were identified in females. There was no change in plasma volume (ES = - 0.03; 95% CI - 0.31, 0.25; p = 0.835), whilst performance test outcomes were improved following heat adaptation (ES = 1.00; 95% CI 0.56, 1.45; p < 0.001). Across all moderators, physiological adaptations were more consistently observed following durations of 451-900 min and/or 8-14 days, exercise intensity ≥ 3.5 kcalmin, total energy expended ≥ 3038 kcal, consecutive (daily) frequency and total heat dose ≥ 23,000 °Cmin. The magnitude of change in performance test outcomes in the heat was associated with a reduction in heart rate following heat adaptation (standardised mean difference = - 10 beatsmin; 95% CI - 19, - 1; p = 0.031).
CONCLUSIONS
Heat adaptation regimes induce physiological adaptations beneficial to thermoregulation and performance test outcomes in the heat in females. Sport coaches and applied sport practitioners can utilise the framework developed in this review to design and implement heat adaptation strategies for females.
Topics: Male; Humans; Female; Hot Temperature; Thermotolerance; Adaptation, Physiological; Exercise; Body Temperature Regulation
PubMed: 37222863
DOI: 10.1007/s40279-023-01831-2 -
Revista Paulista de Pediatria : Orgao... 2023To evaluate the relationship between birth weight and the autonomic nervous system in adulthood through a systematic review. (Review)
Review
OBJECTIVE
To evaluate the relationship between birth weight and the autonomic nervous system in adulthood through a systematic review.
DATA SOURCE
This is a systematic review of publications without limitation of year and language. We included studies involving the autonomic nervous system and birth weight in adults. Manuscripts were selected based on electronic searches of Medical Literature Analysis and Retrieval System Online (MEDLINE), Cumulative Index to Nursing and Allied Health Literature (CINAHL), Web of Science Cochrane Library and Scopus databases, using "Autonomic Nervous System" OR "Heart Rate" OR "Heart Rate Variability" AND "Birth Weight" as a search strategy. This review is registered on the International Prospective Register of Systematic Reviews - PROSPERO (ID: CRD42020165622).
DATA SYNTHESIS
We found 894 articles; 215 were excluded for duplicity. Of the remaining 679 studies, 11 remained. Two were excluded because they did not specifically treat the autonomic nervous system or birth weight. There were nine publications, two cohort and seven cross-sectional studies. The main findings were that extreme, very low, low or high birth weight may have some impact on the autonomic nervous system in adult life.
CONCLUSIONS
Birth weight outside the normality rate may have a negative influence on the autonomic nervous system, causing autonomic dysfunction and increasing the risk of cardiovascular diseases in adult life. Thus, the importance of the follow-up of health professionals from pregnancy to gestation and throughout life, with preventive care being emphasized.
Topics: Adult; Female; Humans; Pregnancy; Autonomic Nervous System; Birth Weight; Cardiovascular Diseases; Cross-Sectional Studies; Systematic Reviews as Topic
PubMed: 37937677
DOI: 10.1590/1984-0462/2024/42/2023002 -
Sensors (Basel, Switzerland) Feb 2024The use of radar technology for non-contact measurement of vital parameters is increasingly being examined in scientific studies. Based on a systematic literature search... (Review)
Review
The use of radar technology for non-contact measurement of vital parameters is increasingly being examined in scientific studies. Based on a systematic literature search in the PubMed, German National Library, Austrian Library Network (Union Catalog), Swiss National Library and Common Library Network databases, the accuracy of heart rate and/or respiratory rate measurements by means of radar technology was analyzed. In 37% of the included studies on the measurement of the respiratory rate and in 48% of those on the measurement of the heart rate, the maximum deviation was 5%. For a tolerated deviation of 10%, the corresponding percentages were 85% and 87%, respectively. However, the quantitative comparability of the results available in the current literature is very limited due to a variety of variables. The elimination of the problem of confounding variables and the continuation of the tendency to focus on the algorithm applied will continue to constitute a central topic of radar-based vital parameter measurement. Promising fields of application of research can be found in particular in areas that require non-contact measurements. This includes infection events, emergency medicine, disaster situations and major catastrophic incidents.
Topics: Heart Rate; Respiratory Rate; Radar; Signal Processing, Computer-Assisted; Algorithms; Vital Signs; Monitoring, Physiologic
PubMed: 38339721
DOI: 10.3390/s24031003 -
Revista Brasileira de Enfermagem 2023to map the scientific evidence on the use of abdominal compressions during cardiopulmonary resuscitation in patients with cardiac arrest. (Review)
Review
OBJECTIVES
to map the scientific evidence on the use of abdominal compressions during cardiopulmonary resuscitation in patients with cardiac arrest.
METHODS
this is a scoping review based on the question: "What is the evidence regarding the use of abdominal compressions during cardiopulmonary resuscitation in patients with cardiac arrest?". Publications up to August 2022 were collected from eight databases. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews was used.
RESULTS
seventeen publications were included. The identified general population consisted of adults and elderly individuals. The primary outcome revealed significant rates of return of spontaneous circulation. Secondary outcomes indicated a significant improvement in heart rate, blood pressure, oxygen saturation, and other outcomes.
CONCLUSIONS
abdominal compressions have been shown to be beneficial. However, further clinical studies are needed to identify the best execution method and its impacts.
Topics: Adult; Humans; Aged; Cardiopulmonary Resuscitation; Heart Arrest; Pressure; Blood Pressure; Heart Rate
PubMed: 38018609
DOI: 10.1590/0034-7167-2022-0400