PURPOSE To determine the normal reference range of pulsatile ocular blood flow (POBF) values in healthy Korean subjects and to find out the factors that may affect them. METHODS A total of 280 eyes of 280 normal subjects were included in this study. Best corrected visual acuity (BCVA), intraocular pressure (IOP), axial length, POBF, systemic blood pressure, and pulse rate were measured. The m...

• During the last fifty years a number of physical theories have been proposed in an attempt to describe analytically the behavior of pulsatile flow in the mammalian arterial system. In order to make such an approach to a system of nonuniform, viscoelastic vessels containing a non-Newtonian fluid at all possible, it becomes necessary to introduce simplifying assumptions, the judicious selection...

A fundamental study to characterize the flow around an oscillating cylinder in a pulsatile flow environment is investigated. This work is motivated by a new proposed design of the total artificial lung (TAL), which is envisioned to provide better gas exchange. The Navier-Stokes computations in a moving frame of reference were performed to compute the dynamic flow field surrounding the cylinder....

Forty four patients undergoing open heart surgery were divided into three groups. Group 1 (17 patients) underwent routine anaesthesia and surgery; group 2 (17 patients) received two doses of methylprednisolone (30 mg/kg), one during induction of anaesthesia and the other immediately before induction of cardiopulmonary bypass; and group 3 (10 patients) received pulsatile flow while undergoing pu...

This paper presents a numerical study of the behaviour of wall shear stress (WSS) in three-dimensional pulsatile flow through an axisymmetric stenosed artery. A realistic blood flow rate (250 ml min−1 at rest in coronary artery [7]) and cardiac cycle (T=0.84s [5]) are applied in the simulations. The flow is fully three-dimensional, and the fluid is assumed to be Newtonian and incompressible. Di...

Although there is no consensus as to the precise nature of the mechanostimulatory signals imparted to the bone cells during remodeling, it has been postulated that deformation-induced fluid flow plays a role in the mechanotransduction pathway. In vitro, osteoblasts respond to fluid shear stress with an increase in PGE(2) production; however, the long-term effects of fluid shear stress on cell p...

Continuous-flow left ventricular assist devices (CF-LVADs) generally operate at a constant speed, which reduces pulsatility in the arteries and may lead to complications such as functional changes in the vascular system, gastrointestinal bleeding, or both. The purpose of this study is to increase the arterial pulse pressure and pulsatility by controlling the CF-LVAD flow rate. A MicroMed DeBake...

• The problems of characterizing pulsatile patterns of pressure and flow in the arterial system are intriguing and complex. Ejection of blood from the left ventricle initiates nonlinear transients in pressure and flow at the root of the aorta. These transients initiate complex pulse patterns that are propagated throughout the arterial tree. Some of the factors that must be reckoned with in an a...

The theory of dynamic fluid motion involving the forces manifested by mass, acceleration, viscous friction and vessel wall tension have been considered and studied when arterial blood flow and pressure are pulsatile. These studies and considerations have resulted in the conclusion that arterial blood pressure is dependent upon all of these parameters and that the relationship of pressure and fl...

The heart’s natural provision of pulsatile blood flow has been regarded as an essential requirement for normal organ function, especially critical organs such as the kidney, liver, and brain. However, in this issue of Circulation, Russell and colleagues1 have demonstrated that this tenet of medicine is no longer accurate. Their study examined the long-term impact of nonpulsatile blood flow as p...