University of Cape Town (UCT) - Department of Anaesthesia and Perioperative Medicine, University of Cape Town (UCT) - Department of Anaesthesia and Perioperative Medicine, Department of Anaesthesia and Perioperative Medicine, Groote Schuur Hospital, and Senior Scholar, Department of Surgery, Faculty of Health Sciences, University of Cape Town, Division of Critical Care, Department of Anaesthesia and Perioperative Medicine, Groote Schuur Hospital, Faculty of Health Sciences, University of Cape Town, Department of Surgery, College of Medicine, University of Lagos and Lagos University Teaching Hospital, Anaesthesia, Cardiothoracic Anaesthetist and Intensivist, Korle-Bu Teaching Hospital and University of Ghana Medical School, University of Cape Town (UCT) - University of Cape Town Lung InstituteUniversity of Cape Town (UCT) - Centre for Lung Infection and Immunity, Ministry of Health, Ethiopia, Kasr Al Ainy Faculty of Medicine, Cairo University, Faculty of Medicine, University of Tripoli, Faculty of Medicine, Cairo University, Department of Critical Care Medicine, Groote Schuur Hospital, Faculty of Health Sciences, University of Cape Town, Armauer Hansen Research Institute, Armauer Hansen Research Institute, Department of Statistical Sciences, Faculty of Science, University of Cape Town, Department of Anaesthesia and Perioperative Medicine, Groote Schuur Hospital, Faculty of Health Sciences, University of Cape Town, Debre Berhan University College of Medicine Department of Anaesthesia, Department of Anaesthesiology, Sefako Makgatho Health Sciences University, Glasgow Royal Infirmary, Armauer Hansen Research Institute, Department of Medicine, Divisions of Critical Care and Pulmonology, Charlotte Maxeke Johannesburg Academic Hospital and Faculty of Health Sciences, University of the Witwatersrand, College of Medicine, University of Ibadan, University of Ghana Medical School, Korle Bu Teaching Hospital and University of Ghana Medical Centre, Department of Critical Care, Steve Biko Academic Hospital, Faculty of Health Sciences, University of Pretoria, Department of Anaesthesia and Perioperative Medicine, Groote Schuur Hospital, Faculty of Health Sciences, University of Cape Town, School of Clinical Medicine. Faculty of Health Sciences, University of the Witwatersrand, Ministry of Health, Ethiopia, Nuffield Department of Surgical Sciences, University of Oxford, Safe Surgery South Africa, NPC, Anaesthesiology & Critical Care, School of Clinical Medicine, University of KwaZulu Natal and Independent