title: Flow distribution during cardiopulmonary bypass in dependency on the outflow cannula positioning.
abstract: Oxygen deficiency in the right brain is a common problem during cardiopulmonary bypass (CPB). This is linked to an insufficient perfusion of the carotid and vertebral artery. The flow to these vessels is strongly influenced by the outflow cannula position, which is traditionally located in the ascending aorta. Another approach however is to return blood via the right subclavian artery. A computational fluid dynamics (CFD) study was performed for both methods and validated by particle image velocimetry (PIV). A 3-dimensional computer aided design model of the cardiovascular (CV) system was generated from realtime computed tomography and magnetic resonance imaging data. Mesh generation (CFD) and rapid prototyping (PIV) were used for the further model creation. The simulations were performed assuming usual CPB conditions, and the same boundary conditions were applied for the PIV validation. The flow distribution was analyzed for 55 cannula positions inside the aorta and in relation to the distance between the cannula tip and the vertebral artery branch for subclavian cannulation. The study reveals that the Venturi effect due to the cannula jet appears to be the main reason for the loss in cerebral perfusion seen clinically. It provides a PIV-validated CFD method of analyzing the flow distribution in the CV system and can be transferred to other applications.
authors.affiliation: Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Aachen, Germany. kaufmann@hia.rwth-aachen.de
authors.forename: Tim A S
authors.initials: TA
authors.lastname: Kaufmann
authors.forename: Marcus
authors.initials: M
authors.lastname: Hormes
authors.forename: Marco
authors.initials: M
authors.lastname: Laumen
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Timms
authors.forename: Thomas
authors.initials: T
authors.lastname: Schmitz-Rode
authors.forename: Anton
authors.initials: A
authors.lastname: Moritz
authors.forename: Omer
authors.initials: O
authors.lastname: Dzemali
authors.forename: Ulrich
authors.initials: U
authors.lastname: Steinseifer
mesh_terms: D001783:Blood Flow Velocity; D002315:Cardiopulmonary Bypass / Q000379:methods*; D002560:Cerebrovascular Circulation; D003198:Computer Simulation; D006801:Humans; D008955:Models, Cardiovascular