نتایج جستجو برای: pulsatile flow
تعداد نتایج: 485950 فیلتر نتایج به سال:
BACKGROUND Late complications after Fontan procedure may be due to the absence of pump and pulsatile pulmonary blood flow in this type of palliation. Our aim was to quantify the degree of pulsation by echocardiographic method in patients with extracardiac total cavopulmonary connection (ECTCPC) in comparison with biventricular circulation and few cases of pulsatile Fontan. METHODS In a case s...
The pumping mechanism of the heart is pulsatile, so the heart generates pulsatile flow that enters into the compliant aorta in the form of pressure and flow waves. We hypothesized that there exists a specific heart rate at which the external left ventricular (LV) power is minimized. To test this hypothesis, we used a computational model to explore the effects of heart rate (HR) and aortic rigid...
In this day and age of cardiovascular surgery with cardiopulmonary bypass (CPB), the perfusionist strives to maintain or mimic normal physiologic parameters such as blood gases, electrolytes, blood flows and so on. The surgical team employes such myocardial protection techniques as topical cooling and cardioplegia. The anaesthesiologist endeavours to maintain hemodynamic and respiratory paramet...
PURPOSE To validate conventional phase-contrast MRI (PC-MRI) measurements of steady and pulsatile flows through stenotic phantoms with various degrees of narrowing at Reynolds numbers mimicking flows in the human iliac artery using stereoscopic particle image velocimetry (SPIV) as gold standard. MATERIALS AND METHODS A series of detailed experiments are reported for validation of MR measureme...
OBJECTIVE Brain damage is universal in the rare survivor of unwitnessed cardiac arrest. Non-pulsatile-controlled cerebral reperfusion offsets this damage, but may simultaneously cause brain oedema when delivered at the required the high mean perfusion pressure. This study analyses pulsatile perfusion first in control pigs and then using controlled reperfusion after prolonged normothermic brain ...
Pulsatile tinnitus usually means a turbulent flow within the vessels. We describe a 54-year-old man with a disabling objective pulsatile tinnitus due to a diverticulum of the sigmoid sinus toward the ipsilateral mastoid. We performed a surgical intervention via the endovascular route using coils to obliterate the diverticulum and a stent to avoid coil migration . The patient had a complete and ...
We present an analysis of the accuracy of the lattice Boltzmann BGK (LBGK) method in simulating pulsatile blood flow in a model of the Human Abdominal Aorta. The flow is driven by a systolic pressure cycle. As a benchmark, we consider fully developed pulsatile flow in a straight tube. We compare velocity profiles and shear stress to the analytical Womersley solutions. The accuracy of the bounce...
In quantitative ultrasonic flow measurements, the beam-to-flow angle (i.e., Doppler angle) is an important parameter. An autoregressive (AR) spectral analysis technique in combination with the Doppler spectrum broadening effect was previously proposed to estimate the Doppler angle. Since only a limited number of flow samples are used, real-time two-dimensional Doppler angle estimation is possib...
OBJECTIVE Various types of rotary blood pumps (axial flow, centrifugal) have been introduced into clinical use recently. These pumps have different pressure-flow characteristics, and some investigators have noted that a limited pump flow rate and less pulsatility are the problems with the axial flow devices. METHODS A new implantable centrifugal blood pump was developed that has an extremely ...
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