Cardiothoracic and Vascular Intensive Care Unit, Auckland City Hospital, Auckland, New Zealand. Medical Research Institute of New Zealand, Wellington, New Zealand. Australian and New Zealand Intensive Care Research Centre, School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia. New Zealand Blood Service, Auckland, New Zealand. School of Nursing, The University of Auckland, Auckland, New Zealand. Greenlane Department of Cardiothoracic Anaesthesia, Auckland City Hospital, Auckland, New Zealand. Faculty of Medicine, University of Queensland, Royal Brisbane and Women's Hospital, Herston, Queensland, Australia. Australian Red Cross Lifeblood, Alexandria, New South Wales, Australia. Joint Health Command, Australian Defence Force, Canberra, Australian Capital Territory, Australia.