Exemplary cases: Cardiopulmonary Bypass

Patient-specific CFD simulations can be used to investigate the flow field during cardiopulmonary bypass (CPB) and reduce the risks of neurological complications. However, standard CFD models neglect the wall movement and the dynamical behavior of cerebral autoregulation (CA) mechanisms.

To overcome these obstacles a multiscale multiphysic description was established which includes cerebral autoregulation and movement of aortic walls on the basis of in vivo measurements. First, the Baroreflex mechanism, which plays a leading role in CA, was represented with a 0-D control circuit. The model parameters were assessed with respect to their physiological meaning and their influence on cerebral blood flow. The control circuit was translated into a system of ordinary differential equations and coupled to the boundaries of the 3-D model. Additionally a fully coupled Fluid-Structure-Interaction (FSI) model was set up, considering the interaction between the blood and the aortic walls.

The final model can mimic hypertensive and impaired autoregulation states. Further on the influence of anesthetic agents on cerebral autoregulation can be reproduced. In summary the presented framework shows the possibility of a 0-D/3-D multiscale multiphysics approach for patient-specific CFD simulations of CPB with personalized boundary conditions.

Multiscale multiphysics simulation of cardiopulmonary bypass (CPB)



Kaufmann TAS, Neidlin M, Buesen M, Sonntag SJ, Steinseifer U. Implementation of Intrinsic Lumped Parameter Modeling into Computational Fluid Dynamicy Studies of Cardiopulmonary Bypass; J Biomech, 2014; DOI: 10.1016/j.jbiomech.2013.11.005

Neidlin M, Steinseifer U, Kaufmann TAS. A multiscale 0-D/3-D approach to patient-specific adaptation of a cerebral autoregulation model for computational fluid dynamics studies of cardiopulmonary bypass. J Biomech 2014.

Neidlin M, Sonntag SJ, Steinseifer U, Kaufmann TAS. A 0-D/3-D Multiscale Multiphysics Approach to Computational Fluid Dynamics Studies of Cardiopulmonary Bypass. 60th ASAIO Washington DC, June 18-21,2014