1. Centre for Anaesthesia, University College Hospital, London, United Kingdom, and Consultant in Anaesthesia, University College London Hospitals NHS (National Health Service) Foundation Trust, London, United Kingdom.
2. Centre for Anaesthesia, University College Hospital, and Locum Consultant in Anaesthesia, Hexham General Hospital Northumbria NHS Trust, Hexham, United Kingdom.
3. Centre for Anaesthesia, University College Hospital; Professor of Anaesthesia and Critical Care Medicine, University of Southampton, Southampton, United Kingdom; Consultant in Critical Care Medicine, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom; and Director, National Institute of Academic Anaesthesia Health Services Research Centre and British Oxygen Company
4. Consultant and Honorary Senior Lecturer in Anaesthesia and Critical Care Medicine, University College London Hospitals NHS Foundation Trust; Director, UCL/UCLH Surgical Outcome Research Centre (SOuRCe), Department of Applied Health Research, University College London, London, United Kingdom; and Centre for Anaesthesia, University College Hospital.