title: Flow mixing during peripheral veno-arterial extra corporeal membrane oxygenation - A simulation study.
abstract: Peripheral veno-arterial extra-corporeal membrane oxygenation (ECMO) is an artificial circulation that supports patients with severe cardiac and respiratory failure. Differential hypoxia during ECMO support has been reported, and it has been suggested that it is due to the mixing of well-perfused retrograde ECMO flow and poorly-perfused antegrade left ventricle (LV) flow in the aorta. This study aims to quantify the relationship between ECMO support level and location of the mixing zone (MZ) of the ECMO and LV flows. Steady-state and transient computational fluid dynamics (CFD) simulations were performed using a patient-specific geometrical model of the aorta. A range of ECMO support levels (from 5% to 95% of total cardiac output) were evaluated. For ECMO support levels above 70%, the MZ was located in the aortic arch, resulting in perfusion of the arch branches with poorly perfused LV flow. The MZ location was stable over the cardiac cycle for high ECMO flows (>70%), but moved 5cm between systole and diastole for ECMO support level of 60%. This CFD approach has potential to improve individual patient care and ECMO design.
authors.affiliation: Sydney Medical School, University of Sydney, Sydney, Australia; Graduate School of Biomedical Engineering, University of New South Wales Sydney, Australia; Sydney Translational Imaging Laboratory, Heart Research Institute, Charles Perkins Centre, University of Sydney, Camperdown, Australia. Electronic address: michael.stevens@unsw.edu.au.
authors.forename: M C
authors.initials: MC
authors.lastname: Stevens
authors.affiliation: Sydney Medical School, University of Sydney, Sydney, Australia; Sydney Translational Imaging Laboratory, Heart Research Institute, Charles Perkins Centre, University of Sydney, Camperdown, Australia.
authors.forename: F M
authors.initials: FM
authors.lastname: Callaghan
authors.affiliation: Sydney Medical School, University of Sydney, Sydney, Australia; Department of Anaesthetics, Royal Prince Alfred Hospital, Sydney, Australia.
authors.forename: P
authors.initials: P
authors.lastname: Forrest
authors.affiliation: Sydney Medical School, University of Sydney, Sydney, Australia; Department of Anaesthetics, Royal Prince Alfred Hospital, Sydney, Australia; Institute of Academic Surgery, Royal Prince Alfred Hospital, Sydney, Australia; The Baird Institute, Sydney, Australia.
authors.forename: P G
authors.initials: PG
authors.lastname: Bannon
authors.affiliation: Sydney Medical School, University of Sydney, Sydney, Australia; Sydney Translational Imaging Laboratory, Heart Research Institute, Charles Perkins Centre, University of Sydney, Camperdown, Australia; Department of Radiology, Royal Prince Alfred Hospital, Sydney, Australia.
authors.forename: S M
authors.initials: SM
authors.lastname: Grieve
mesh_terms: D000328:Adult; D001011:Aorta / Q000503:physiopathology*; D002302:Cardiac Output; D003198:Computer Simulation; D015199:Extracorporeal Membrane Oxygenation; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D057446:Hydrodynamics; D008297:Male; D008954:Models, Biological; D012131:Respiratory Insufficiency / Q000503:physiopathology / Q000628:therapy; D014680:Veins / Q000503:physiopathology*
keywords: Computational fluid dynamics; ECMO; Extracorporeal circulation; Heart failure; Mechanical circulatory support