Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
Hemodynamics Alterations Induced by Central Venous Catheter in Vascular Access for Hemodialysis
Submission Author:
Saulo Gonçalves , MG
Co-Authors:
Saulo Gonçalves, Mário Silva, Matheus Carvalho Barbosa Costa, Thabata Lucas, Rudolf Huebner
Presenter: Saulo Gonçalves
doi://10.26678/ABCM.COBEM2021.COB2021-1388
Abstract
. There is a tendency, in worldwide scenario, of increasing the number of patients on dialysis, as well as the prevalence rates in renal replacement therapy and central venous catheter use. The major cause of central venous catheters non-functionality is associated with thrombus formation. The alteration of physical properties in the flow field, induced by the presence of the catheter, may lead to a non-physiological condition of shear stress, strain rate and exposure time, which can be unfavorable in thrombogenic terms. The knowledge of how those physical properties are altered by the presence of the catheter is of fundamental importance for the optimization in the design of those devices. The present study aims to develop a numerical model to compare and analyze the hemodynamic environment in central venous access for hemodialysis, considering the presence and absence of central venous catheter. The simulations were performed in transient regime, covering two complete physiological cardiac cycles of 0.8 s. The geometry of central veins was obtained by computed tomography images of a healthy, 74-year-old male patient. A central venous catheter model similar to the clinical device MedCOMP/HEMO-CATH (Harleysville, PA, USA) was used. The K-w SST turbulence model was used to characterize turbulence. Blood was considered both as Newtonian fluid, and non-Newtonian, modeled by the Carreau-Yasuda equations. It was observed that the catheter was responsible for increasing the values of strain rate, shear stress, as well as generating regions of recirculation, stagnation, and separation of the flow field. The comparison of the percentage increase in shear stress and maximum exposure time along the streamlines, with and without catheter, reinforces the hypothesis that the exposure time may be more significant for the thrombus formation in the region than the shear stress.
Keywords
hemodialysis, computational fluid dynamics., Blood flow, CFD
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