1. Institute of Anesthesiology, University and University Hospital Zurich; Zurich Switzerland
2. Regional Blood Transfusion Service, Zurich Swiss Red Cross; Zurich Switzerland
3. Division of Hematology; University and University Hospital Zurich; Zurich Switzerland
4. Department of Biostatistics, Epidemiology; Biostatistics, and Prevention Institute, University of Zurich; Zurich Switzerland