Search results for "cardiac output"

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…

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…

Transpulmonary cardiac output measurement in a rat model of cardiac arrest and CPR: Impact of vascular access

2009

Objective: The present study investigated the impact of the vascular access site for cardiac output (CO) measurement by thermodilution on survival and neurohistopathological injury in a rat model of cardiac arrest (CA) and cardiopulmonary resuscitation (CPR). Secondary the influence of the vascular access site on cardiac output measurements was examined. Methods: Rats underwent asphyxial CA and CPR. Thermocouple probes were either placed via the femoral artery into the bifurcation of abdominal aorta/iliac artery (Femoral) or via the carotid artery into the aortic arch (Carotid). CPR was initiated after 9 min CA. Local cerebral blood flow (lCBF) and CO were assessed for 120 min after restora…

Modeling Right Ventricle Failure After Continuous Flow Left Ventricular Assist Device: A Biventricular Finite-Element and Lumped-Parameter Analysis

2017

The risk of right ventricle (RV) failure remains a major contraindication for continuous-flow left ventricular assist device (CF-LVAD) implantation in patients with heart failure. It is therefore critical to identify the patients who will benefit from early intervention to avoid adverse outcomes. We sought to advance the computational modeling description of the mechanisms underlying RV failure in LVAD-supported patients. RV failure was studied by computational modeling of hemodynamic and cardiac mechanics using lumped-parameter and biventricular finite element (FE) analysis. Findings were validated by comparison of bi-dimensional speckle-tracking echocardiographic strain assessment of the …

The Hemodynamic Effects of Ephedrine on the Onset Time of Rocuronium in Pigs

2004

Several studies have found a correlation between the onset time of muscle relaxants, cardiac index, and muscle blood flow. Ephedrine increases these hemodynamic variables and shortens onset time of rocuronium in humans. Our aim in this animal study was to determine the effect of ephedrine on the onset time of rocuronium, cardiac index, and muscle blood flow after administration of thiopental. At predefined measuring points, mean arterial blood pressure and cardiac index were measured invasively and onset time was determined mechanomyographically. Twenty-four pigs were randomly assigned to three groups. Group I received etomidate and subsequently rocuronium (2 x 95% effective dose). Instead …

A model of stepwise isovolaemic blood exchange in anaesthetised, spontaneously breathing rats to evaluate the oxygen transport efficiency of artifici…

2000

Our research pursues the production of hypo-oncotic artificial oxygen carriers, based on artificial covalently cross-linked hyperpolymeric mammalian haemoglobins. To evaluate their in vivo efficiency in oxygen delivery to the tissue we developed a small animal model of stepwise isovolaemic blood exchange in anaesthetised, spontaneously breathing rats. With the aid of a two-way respiratory micro valve for small animals the overall oxygen uptake by the tissue of the animal can be determined. Measurements of oxygen contents in arterial and mixed venous blood and of some further blood parameters together with known oxygen-binding characteristics of artificial and native oxygen carriers, permits…

Inhaled Prostacyclin, Nitric Oxide, and Nitroprusside in Pulmonary Hypertension After Mitral Valve Replacement

2005

Abstract Objective: Pulmonary hypertension increases morbidity and mortality in patients undergoing heart surgery. Mitral valve stenosis is frequently associated with an increase in pulmonary vascular resistance (PVR). Cardiopulmonary bypass exacerbates pulmonary hypertension in patients undergoing cardiac surgery. The aim of this study was to compare the hemodynamic effects of inhaled prostacyclin and nitric oxide and the administration of i.v. nitroprusside during cardiac surgery with a clinical, pharmacodynamic dose-response, prospective, randomized, and double-blind study (Group A: inhaled prostacyclin; Group B: inhaled nitric oxide; Group C: nitroprusside). Materials and Methods: Fifty…

Extreme Pulsus Alternans with P Wave Alternans in a Child

2002

Pulsus alternans was observed in a child with left ventricular dysfunction secondary to systemic hypertension. The Echo-Doppler of supravalvular aorta and a simultaneous electrocardiographic trace (ECG) clearly demonstrated the mechanism of an apparent abrupt halving of pulse frequency compared with the ECG, similar to an electromechanical dissociation 2: 1. Besides the extreme pulsus alternans, a P wave and a PP cycle length change were also observed. Both mechanical and electrical alternans disappeared with afterload reduction by nitroprusside treatment.

First-degree atrioventricular block and pseudopacemaker syndrome

2013

Particle image velocimetry study of the celiac trunk hemodynamic induced by continuous-flow left ventricular assist device

2017

Abstract Whereas left ventricular assist device (LVAD) is the gold-standard therapy for patients with heart failure, gastrointestinal bleeding is one of the most common complications. LVAD implantation may remarkably impact aortic hemodynamics so that experimental and computational flow analyses can be used to study the disease mechanisms. Here we present an experimentally-calibrated computational model of the celiac trunk hemodynamic of a LVAD-supported patient who experienced bleeding after device implantation. Specifically, both particle image velocimetry (PIV) and echocardiography were used to measure and compare flow distributions in each branch of a phantom model of the patient abdomi…