Search results for "cardiac output"
showing 10 items of 95 documents
Hemodynamic Parameters Change Earlier Than Tissue Oxygen Tension in Hemorrhage
2010
BACKGROUND: Untreated hypovolemia results in impaired outcome. This study tests our hypothesis whether general hemodynamic parameters detect acute blood loss earlier than monitoring parameters of regional tissue beds. MATERIALS AND METHODS: Eight pigs (23-25 kg) were anesthetized and mechanically ventilated. A pulmonary artery catheter and an arterial catheter were inserted. Tissue oxygen tension was measured with Clark-type electrodes in the jejunal and colonic wall, in the liver, and subcutaneously. Jejunal microcirculation was assessed by laser Doppler flowmetry (LDF). Intravascular volume was optimized using difference in pulse pressure (dPP) to keep dPP below 13%. Sixty minutes after p…
Description of the response of a new multi-parametric brain sensor to physiological and pathophysiological challenges in the cortex of juvenile pigs
2014
AIM Monitoring of intracranial pressure (ICP), local cerebral blood flow (CBF) and oxygen is part of modern intensive critical care medicine. Preclinical evaluation of newly developed catheters that should monitor several parameters simultaneously is reported poorly in the literature. The goal of our study was (1) to evaluate a new multi-parametric sensor in brain tissue and (2) to establish a testing protocol using pathophysiological challenges that target measured parameters of the sensor and autoregulatory boundaries and could be used as preclinical standard protocol in future studies. MATERIAL AND METHODS We describe data from 12 new multi-parametric brain sensors (MPBS) that were impla…
The oxygen status of arterial human blood
1990
The oxygen status of arterial human blood is described at least by four variables: Oxygen partial pressure (pO2, mmHg), oxygen saturation (sO2, %), hemoglobin content (cHb, g/dL) and oxygen content (cO2, mL/dL). Beside perfusion, however, the oxygen supply of all organs is decisively determined by the mean capillary pO2 which itself is primarily dependent on the arterial cO2. Therefore, the oxygen availability (cardiac output x caO2, mL/min) may be described by the cO2 value in arterial blood or those variables who determine the latter one. The diagnostic significance of the O2 variables of the oxygen status consequently increases in the order of pO2, sO2 (cHb) and cO2. In arterial blood, o…
Hemodynamic Instability in Heart Failure Intensifies Age-Dependent Cognitive Decline
2020
This review attempts to examine two key elements in the evolution of cognitive impairment in the elderly who develop heart failure. First, major left side heart parts can structurally and functionally deteriorate from aging wear and tear to provoke hemodynamic instability where heart failure worsens or is initiated; second, heart failure is a major inducer of cognitive impairment and Alzheimer's disease in the elderly. In heart failure, when the left ventricular myocardium of an elderly person does not properly contract, it cannot pump out adequate blood to the brain, raising the risk of cognitive impairment due to the intensification of chronic brain hypoperfusion. Chronic brain hypoperfus…
Breathing 100% oxygen during water immersion improves postimmersion cardiovascular responses to orthostatic stress
2016
Abstract Physiological compensation to postural stress is weakened after long‐duration water immersion (WI), thus predisposing individuals to orthostatic intolerance. This study was conducted to compare hemodynamic responses to postural stress following exposure to WI alone (Air WI), hyperbaric oxygen alone in a hyperbaric chamber (O 2 HC), and WI combined with hyperbaric oxygen (O 2 WI), all at a depth of 1.35 ATA, and to determine whether hyperbaric oxygen is protective of orthostatic tolerance. Thirty‐two healthy men underwent up to 15 min of 70° head‐up tilt (HUT) testing before and after a single 6‐h resting exposure to Air WI ( N = 10), O 2 HC ( N = 12), or O 2 WI ( N = 10). Heart …
Meox2/Tcf15 Heterodimers Program the Heart Capillary Endothelium for Cardiac Fatty Acid Uptake
2015
Background— Microvascular endothelium in different organs is specialized to fulfill the particular needs of parenchymal cells. However, specific information about heart capillary endothelial cells (ECs) is lacking. Methods and Results— Using microarray profiling on freshly isolated ECs from heart, brain, and liver, we revealed a genetic signature for microvascular heart ECs and identified Meox2/Tcf15 heterodimers as novel transcriptional determinants. This signature was largely shared with skeletal muscle and adipose tissue endothelium and was enriched in genes encoding fatty acid (FA) transport–related proteins. Using gain- and loss-of-function approaches, we showed that Meox2/Tcf15 media…
Beta-adrenergic blocking activity and haemodynamic effects in man of K� 1313, a new beta-adrenergic antagonist
1971
The beta-adrenergic blocking activity and haemodynamic effects of o-[2-hydroxy-3-(isopropylamino)-propoxy]-benzonitril (Ko 1313) have been studied in 22 patients. Antagonism of isoproterenol-induced tachycardia was used as a measure of the beta-adrenergic blocking activity. Ko 1313 1.0 mg had its maximum beta-adrenoceptor blocking effect 5–30 min after intravenous injection. Ko 1313 10.0 mg produced maximum betablockade 1–4 h after oral administration. 1.0 mg Ko 1313 injected intravenously had approximately the same beta-adrenergic blocking effect as 1.0 mg propranolol also given intravenously. After intravenous administration Ko 1313 was 3–4 times as potent as the same dose given orally. A…
Dibutyryl cyclic AMP and adrenaline increase contractile force and 45Ca uptake in mammalian cardiac muscle
1973
The effects of dibutyryl cyclic AMP (DB-AMP; 10−3M) and adrenaline (2.2×10−6 M) on contractile force, 45Ca uptake, and total myocardial Ca concentration were investigated in electrically driven left auricles isolated from rat hearts. The experiments were performed at an extracellular Ca concentration of 0.45 mM and at low frequency of stimulation (15 beats/min). 45Ca exposure was 5 min. Under the conditions used, both drugs increased contractile force and enhanced 45Ca uptake (expressed as relative specific activity) by about 30% (DB-AMP) and 40% (adrenaline), respectively. Thus, the results provide evidence that the effects of adrenaline on 45Ca uptake in mammalian cardiac muscle can be mi…
Bigger is not better: cortisol-induced cardiac growth and dysfunction in salmonids
2015
This is a Published Manuscript of an article published by Company of Biologists in Journal of Experimental Biology, available online: http://www.biologists.com/ Stress and elevated cortisol levels are associated with pathological heart growth and cardiovascular disease in humans and other mammals. We recently established a link between heritable variation in post-stress cortisol production and cardiac growth also in salmonid fish. A conserved stimulatory effect of the otherwise catabolic steroid hormone cortisol is likely implied, but has to date not been established experimentally. Furthermore, whereas cardiac growth is associated with failure of the mammalian heart, pathological cardiac h…
Effect of acute systemic hypoxia on human cutaneous microcirculation and endothelial, sympathetic and myogenic activity
2015
The regulation of cutaneous vascular tone impacts vascular vasomotion and blood volume distribution as a challenge to hypoxia, but the regulatory mechanisms yet remain poorly understood. A skin has a very compliant circulation, an increase in skin blood flow results in large peripheral displacement of blood volume, which could be controlled by local and systemic regulatory factors. The aim of this study was to determine the acute systemic hypoxia influence on blood flow in skin, local regulatory mechanism fluctuations and changes of systemic hemodynamic parameters. Healthy subjects (n=11; 24.9±3.7years old) participated in this study and procedures were performed in siting position. After 2…