Computational evaluation of heart failure and continuous flow left ventricular assist device support in anaemia

International Journal for Numerical Methods in Biomedical Engineering, Journal Year: 2023, Volume and Issue: unknown

Published: Oct. 10, 2023

Abstract Anaemia is common in end‐stage heart failure patients supported with continuous flow left ventricular assist device (CF‐LVAD) and associated adverse outcomes such as readmission. This study evaluates the haemodynamic effects of anaemia on cardiac function cerebral blood CF‐LVAD using computational simulations. A dynamic model simulating function, systemic, pulmonary circulations, autoregulatory mechanisms gas contents was used to evaluate iron deficiency during support. therapy simulated by a describing HeartMate 3. were reducing haemoglobin level from 15 9 g/dL modifying scaling coefficients models chamber volumes. Reduced levels decreased arterial O 2 content, which increased rate more than 50% assistance. had minimal effect atrial pressures In contrast, end‐diastolic right diameters 6.6 cm 7 2.9 3.1 support 6.1 6.4 3.3 cm. The developed numerical simulates failing therapy. It good agreement clinical data can be utilised assess

Language: Английский

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Cerebral Vasoreactivity

Published: Jan. 1, 2022

Cerebral blood flow is mainly regulated by two mechanisms: cerebral autoregulation and neurovascular coupling (NVC). maintains a constant within the physiological range of systemic pressures, which predominantly operated through myogenic response. The microcirculation supplied parenchymal arterioles, form functional unit with adjacent nerve terminals astrocytes that encase known as unit. Such morphological arrangement ensures rapid spatial temporal increases in response to neuronal activation, NVC. A broad metabolic factors, vascular active agents, activities are involved processes NVC affecting reactivity. Among them, most prominent ones include O2, CO2, adenosine, nitric oxide, prostaglandins, epoxyeicosatrienoic acids, regulation.

Language: Английский

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Effect of Carboxy Therapy combined with High Intensity Training on blood pressure in Patients with Metabolic Syndrome

Egyptian Journal of Physical Therapy, Journal Year: 2022, Volume and Issue: 12(1), P. 7 - 11

Published: Dec. 1, 2022

Background: metabolic syndrome is a common and worldwide diseases affecting humans.It can be considered major health problem throughout the world as it has high prevalence, lead to increased risk of cardiovascular liver diseases.Aim Work: determine efficacy carboxy therapy combined with intensity training on blood pressure in patients syndrome.Patients Methods: Eighty female diagnosed selected from Al Shohadaa Central Hospital were this study Their age determined 50 60 years old.Patients assigned two groups equal number :group A (study group), consisted 40 patient, women group interventioned by (3 sessions per week) (2 times for 4 weeks.Group B (control group): women, both following ((low fat low calorie diet ) weeks .blood was measured before after at end .Results: there statistically significant decrease systolic diastolic pre/post data (p<0.05),with improvement more than all outcome data.Conclusion: carboxytherapy High interval caloric improve syndrome.

Language: Английский

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Lessons from on high: arterial CO₂, not pH, is the key mediator of cerebrovascular function

The Journal of Physiology, Journal Year: 2021, Volume and Issue: 599(18), P. 4247 - 4248

Published: July 26, 2021

It is because of this influence that the body relies upon a bicarbonate buffer system, which describes reverse equilibrium between water and CO2, carbonic acid (H2CO3), [H+] ions (HCO3−), with bidirectional anhydrases. The CO2–HCO3− relationship most important pH buffering system within body, utilizing to mitigate large fluctuations in during acute CO2 levels. As such, it can be assumed any interventions capacity will –[H+]/pH relationship. regulatory effect on cerebral blood flow manifests from free diffusion equilibration across blood–brain barrier (BBB) where manipulates cerebrospinal fluid (CSF) perivascular space (Yoon et al. 2012). This observation has been demonstrated both reduced preparations vessels animal models. Once BBB, bicarbonate-buffer along other mechanisms, mitigates deviations normal perivascular/CSF Thus, maintained narrow limits throughout central nervous support neural glial cell function. Prior publications have begun delineate effects manipulating capacity, either pharmacologically or through environmental (high altitude) exposure, CVR sensitivity. goal better understand interaction arterial [H+]/pH regulation. narrative obvious translational significance for pathological conditions affect acid–base regulation, systemically system. In recent publication Journal Physiology, Caldwell (2021b) sought examine induced manipulation status regulation healthy human participants. Resting were measured three distinct experimental conditions: (1) resting balance (control); (2) metabolic acidosis, by way 2 days low-dose oral acetazolamide (ACZ) ingestion; (3) post-arterial normalisation using intravenous infusion sodium (NaHCO3−). Measurements obtained at sea level (344 m) following sojourn to, sustained residence at, high altitude (14–20 5050 m). Under each condition, participants exposed graded isoxic challenge sequence: −10, −5, +0, +5, +10, +15 mmHg. Participants unable tolerate mmHg was subsequently removed final comparisons. Accurate precise achieved an end-tidal forcing Intracranial middle posterior velocities continuously monitored transcranial Doppler ultrasound. Moreover, duplex ultrasound internal carotid vertebral arteries recorded rest, providing direct measurement global flow. standardized approach used measure hypo- hypercapnic ranges. Radial draws prior condition. Furthermore, radial artery catheter inserted allowing repeated samples drawn stage challenge. Several hallmark features physiological response as well ACZ ingestion observed. Relative level, resulted profound reductions , consequent hyperventilatorily resultant respiratory alkalosis. ventilatorily increase partially compensated renal via increased secretion HCO3− (i.e. compensatory acidosis). Consequently, would serve reduce altitude. Across locations, over 2-day period significant acidosis. Importantly, NaHCO3− restored levels control conditions. respect aim study, demonstrates complete restoration reductions, least blood. expected, exposure altered haemodynamics. described, driven loss autoregulation tandem hypoxic vasodilatation vessels. These changes maintain oxygen delivery incidences concentration. key finding study sensitivity unchanged altitude, despite pH. strengths design allowed thorough examination consequential lab-setting setting chronic gas stressor. work complements research group examining alkalosis, extension haemodynamics laboratory (Caldwell 2021a). contrast, examined consequences reducing restoring interesting talking points emerge. current article supports concept function rather than prevailing per se, mediated vasoreactivity. An follow-up these findings could assess relative contribution, if any, endothelial cells assessment. Experimental hypercapnia elicit endothelium intracellular pH, subsequent activation calcium-dependent nitric oxide synthase (eNOS) isoform. A repeat concurrent eNOS antagonism (e.g. Nω-nitro-l-arginine) instructive. help dissociate contribution -dependent derived prospect differential multiple anhydrase inhibitors suggested, magnitude primarily exerts its Whilst routinely prophylaxis ascent, limited penetration rate CNS. methazolamide, sister inhibitor, possesses penetrate might positioned manipulate tenet authors’ re-visited different inhibitor interventions. Finally, authors highlighted intolerance (+15 mmHg) likely consequence CNS such gradient BBB. suggests upper limit threshold Future studies extent particular interest given progressive concomitant ascent higher altitudes. exciting whether lower exists. may independently induce flow, thereby highlighting beyond Whether minimal concentration essential sustain cerebrovascular neurological interest, particularly context high-altitude adaptive augment secretion. technically elegant provides insight into physiology showcasing mediator CBF Please note: publisher not responsible content functionality supporting information supplied authors. Any queries (other missing content) should directed corresponding author article. No competing interests declared. Sole author. None. I am grateful Professors Ken O'Halloran Trevor Day helpful comments first draft Open access funding provided IReL.

Language: Английский

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Does breathing pattern affect cerebrovascular reactivity?

Experimental Physiology, Journal Year: 2021, Volume and Issue: 107(2), P. 183 - 191

Published: Dec. 28, 2021

What is the central question of this study? Is cerebrovascular reactivity affected by isocapnic changes in breathing pattern? main finding and its importance? Cerebrovascular does not change with variations tidal volume frequency.Deviations arterial carbon dioxide tension from resting values affect cerebral blood vessel tone thereby flow. Arterial also affects respiratory chemoreceptors, adjusting drive. This coincidence raises question: drive flow response to dioxide? A for a given defined as (CVR). Two studies have reached conflicting conclusions on question, using voluntary control disturbing factor during measurements CVR. Here, we address some methodological limitations both sequential gas delivery targeted oxygen enable separation effects CVR vigour. We confirm that there no detectable superimposed effect efforts

Language: Английский

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