Topic
Pulsatile flow
About: Pulsatile flow is a research topic. Over the lifetime, 6278 publications have been published within this topic receiving 149638 citations.
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05 Dec 1995
TL;DR: The Mammalian Species The Cardiovascular System Function of the Circulation Book Content Comparative Anatomy and Physiology of thecirculation The Heart Arteries The Veins The Microvasculature Comparative Analysis With Allometry Modeling Principles and Comparison Across Species.
Abstract: Introduction The Mammalian Species The Cardiovascular System Function of the Circulation Book Content Comparative Anatomy and Physiology of the Circulation The Heart Arteries The Veins The Microvasculature Comparative Analysis With Allometry Modeling Principles and Comparison Across Species Allometric Equation and Definitions Growth and Differential Growth The Importance of Body Size and Organ Size Circulatory Allometry Introduction of Allometry to Hemodynamics Dimensional Analysis for Identifying Circulatory Similarities Basic Mathematical Tools Dimensional Analysis and the Pi-Theorem Methods for Establishing Similarity Principles Illustrative Examples Cardiac Mechanics Cardiac Muscle Mechanics Starling's Law Applied to the Mammalian Heart SImilar Ejection Fraction and Contractility of the Heart The Pressure-Volume Curve Arterial System Function Rheological Properties of Mammalian Arteries Pressure and Flow Relationship: The Windkessel and Vascular Input Impedance Pulse Propagation Wavelength and System Length Pulse Wave Reflections Pulsatile Power Generation and Energy Dissipation Similarity Analysis of the Cardiovascular Function Laminar and Turbulent Flow in Mammalian Arteries Blood Pressure and Flow Waveforms Laplace's Law The Heart Rate Energetics and Efficiency of the Mammalian Heart Arterioles, Venules, Capillaries, and the Red Blood Cells Myocardial Oxygen Consumption, Blood Flow, and Metabolic Turn-Over Rate Closed-Loop Analysis of the Circulation Fundamentals of Biological Controls Allometry in Cardiovascular Control Heart-Arterial System Interaction Differentiating the Normal and the Diseased Cardiovascular System Optimality and Similarity External Work, Optimal Power, and Efficiency Geometry and Elasticity: Low Loss Aorta and Branching Characteristics, Minimum Shear Minimum Local Reflections and Area Ratio The Natural Design Characteristics References Index
59 citations
TL;DR: The principle of a method that can reduce the dependence of the Doppler angle of flow measurement by setting the sample points along a line to which every ultrasound beam is perpendicular is described.
Abstract: A new method has been developed for measuring the volume flow rate of blood flowing through large vessels or outflow tracts of the heart. In this article we describe the principle of a method that can reduce the dependence of the Doppler angle of flow measurement by setting the sample points along a line to which every ultrasound beam is perpendicular. To evaluate the accuracy of this method, flow phantom experiments were made for both steady and pulsatile flows. The volume flow rate measured by this method agrees well with that observed by an ultrasound flowmeter ( r =0.99) when the vessel diameter is large (25 mm). However, this method overestimates by 40% when the vessel diameter is small (8 mm). To make this method applicable to small vessels, an improvement in the lateral resolution of Doppler measurement is necessary. It has been concluded that this method can be used to measure the cardiac output or volume flow rates in large vessels.
59 citations
TL;DR: Pulsatile flow generates significantly higher energy, enhancing myocardial flow during and after hypothermic CPB and after 60 minutes of ischemia in this model.
Abstract: Pediatric myocardial related morbidity and mortality after cardiopulmonary bypass (CPB) are well documented, but the effects of pulsatile perfusion (PP) versus nonpulsatile perfusion (NPP) on myocardial blood flow during and after hypothermic CPB are unclear. After investigating the effects of PP versus NPP on myocardial flow during and after hypothermic CPB, we quantified PP and NPP pressure and flow waveforms in terms of the energy equivalent pressure (EEP) for direct comparison. Ten piglets underwent PP (n = 5) or NPP (n = 5). After initiation of CPB, all animals underwent 15 minutes of core cooling (25 degrees C), 60 minutes of hypothermic CPB with aortic cross-clamping, 10 minutes of cold reperfusion, and 30 minutes of rewarming. During CPB, the mean arterial pressure (MAP) and pump flow rates were 40 mm Hg and 150 ml/kg per min, respectively. Regional flows were measured with radiolabeled microspheres. During normothermic CPB, left ventricular flow was higher in the PP than the NPP group (202+/-25 vs. 122+/-20 ml/l 00 g per min). During hypothermic CPB, no significant intragroup differences were observed. After 60 minutes of ischemia and after rewarming (276+/-48 vs. 140+/-12 ml/100 g per min; p < 0.05) and after CPB (271+/-10 vs. 130+/-14 ml/100 g per min; p < 0.05), left ventricular flow was higher in the PP group. Right ventricular flow resembled left ventricular flow. The pressure increase (from MAP to EEP) was 10+/-2% with PP and 1% with NPP (p < 0.0001). The increase in extracorporeal circuit pressure (ECCP) (from ECCP to EEP) was 33+/-10% with PP and 3% with NPP (p < 0.0001). Pulsatile flow generates significantly higher energy, enhancing myocardial flow during and after hypothermic CPB and after 60 minutes of ischemia in this model.
59 citations
TL;DR: In this article, with the help of finite Hankel and Laplace transforms, analytic expressions for axial velocity, fluid acceleration, wall shear and instantaneous volume flow rate have been obtained.
59 citations
TL;DR: In this paper, the influence of pulsatile laminar flow and heating protocol on temperature distribution in a single blood vessel and tumor tissue receiving hyperthermia treatment was investigated using a finite element scheme based on the Galerkin method of weighted residuals.
59 citations