Computational Fluid Dynamics Modeling of Hemodialysis in Patients with an Arteriovenous Fistula
Date of Award
Master of Science (MS)
With the advent of arteriovenous fistula (AVF) for use in hemodialysis, the anastomosis built for such use has become a central point of the study to understand the flow and wall shear stresses in such a system since very large wall shear stresses can lead to arterial/vein rupture. Considering the commonly used creation site of an anastomosis as connecting the radial artery to the cephalic vein, a model is created to calculate the wall shear stresses across various components of the system. The model depicts a connection of the specified vein and artery bridged together allowing the increase in blood flow needed to meet the minimum requirement of 500 mL/min of volumetric flow before hemodialysis can begin. The three-dimensional model also includes the insertion of needles to simulate the pump in the actual hemodialysis procedure with two 17 Gauge needles being inserted in the cephalic vein. Various flow conditions including a constant flow rate up to 750 mL/min and a sinusoidal varying flow rate from 338 to 562 mL/min are included in the simulations. ANSYS Fluent flow solver is used to solve the Reynolds-Averaged Navier-Stokes equations with k-kl-ω transition model for calculating the wall shear stress in the entire model and in particular to identify the areas of maximum wall shear stress. For steady flow rate of 750mL/min, the maximum wall shear stress in the entire system is found to be ~ 410Pa; this value is in the range predicted by other investigators.
David A. Peters Swami Karunamoorthy
Aerodynamics and Fluid Mechanics Commons, Other Biomedical Engineering and Bioengineering Commons