1. Perfusion Services, Nova Scotia Health Authority, Halifax, Nova Scotia, Canada
2. Cardiovascular Surgery, Dept. of Perfusion, University Hospital Giessen and Marburg, Giessen, Germany
3. Department of Surgery, Dalhousie University, Halifax, Nova Scotia, Canada
4. Anesthesiology, Intensive Care, Pain Therapy, University Hospital Giessen and Marburg, Giessen, Germany
5. Wetzlar Community Hospital, Wetzlar, Germany
6. Department of Cardiovascular Surgery, University Hospital Giessen and Marburg, Giessen, Germany
7. Institute for Medical Informatics, Justus-Liebig-University Giessen, Giessen, Germany
8. Medical Statistics, Justus-Liebig-University Giessen, Giessen, Germany
9. Statistics Consultancy, Giessen, Germany
10. Institute of Ageing and Chronic Disease, Royal Liverpool University Hospital, Liverpool, UK
11. Kerckhoff Heart and Lung Center, Bad Nauheim, Germany
12. Department of Anesthesia, Perioperative Medicine and Pain Therapy, Dalhousie University, QEII Health Sciences Centre, Halifax, Canada