نتایج جستجو برای: pulsatile flow

تعداد نتایج: 485950  

2015
Reza Shabanian Mohammad Reza Mirzaaghayan Minoo Dadkhah Mehdi Hosseini Mitra Rahimzadeh Parvin Akbari Asbagh Mohammad Ali Navabi

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...

Journal: :TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B 2008

2011
Niema M. Pahlevan Morteza Gharib

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...

1999
Avdesh N. Mathur Alec D. Thorpe

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...

Journal: :Journal of magnetic resonance imaging : JMRI 2014
Iman Khodarahmi Mostafa Shakeri Melanie Kotys-Traughber Stefan Fischer M Keith Sharp Amir A Amini

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...

Journal: :European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery 2012
Bradley S Allen Yoshihiro Ko Gerald D Buckberg Zhong Tan

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 ...

2011
Tanit Ganz Sanchez Marcia Murao Roberto Torres de Medeiros Marcia Kii Ricardo Ferreira Bento Jose Guilherme Caldas Carlos Alberto Alvarez Carlos Henrique Raggiotto

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 ...

2003
A. M. ARTOLI A. G. HOEKSTRA P. M. A. SLOOT A. M. Artoli A. G. Hoekstra P. M. A. Sloot

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...

Journal: :Ultrasonic imaging 2002
Chih-Kuang Yeh Pai-Chi Li

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...

Journal: :General thoracic and cardiovascular surgery 2007
Kenji Yamazaki Satoshi Saito Shinichiro Kihara Osamu Tagusari Hiromi Kurosawa

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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