Oslo University Hospital & University of Oslo, Oslo, Norway. Centre for Trauma Sciences, Queen Mary University of London, Blizard Institute, 4 Newark Street, London, E1 2AT, UK. Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark. Amsterdam University Medical Centres, Amsterdam, The Netherlands. Oxford University Hospital NHS Trust, Oxford, UK. Cologne-Merheim Medical Centre, University of Witten/Herdecke, Cologne, Germany. Nottingham University Hospitals NHS Trust, Nottingham, UK. Queen Mary University of London, London, UK. NHS Blood and Transplant, Bristol, UK. Centre for Trauma Sciences, Queen Mary University of London, Blizard Institute, 4 Newark Street, London, E1 2AT, UK. k.brohi@qmul.ac.uk.