1. Perioperative Research Unit, Metropolitan Department of Anaesthetics, Critical Care and Pain Management, Pietermaritzburg, University of KwaZulu-Natal, Discipline of Anaesthesiology and Critical Care, Durban, South Africa
2. Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Shatin, Hong Kong
3. Outcomes Research Consortium, Cleveland Clinic, Cleveland, OH, USA