1. Section of Anaesthetics, Pain Medicine and Intensive Care Medicine, Department of Surgery and Cancer, Imperial College London, London, United Kingdom
2. Faculty of Public Health and Policy, London School of Hygiene and Tropical Medicine, London, United Kingdom
3. Imperial Clinical Trials Unit, School of Public Health, Imperial College London, London, United Kingdom
4. Warwick Clinical Trials Unit, Warwick Medical School, University of Warwick, Coventry, United Kingdom
5. Anaesthesia and Intensive Care Medicine, St George's University Hospitals National Health Service Foundation Trust, London, United Kingdom
6. Intensive Care Unit, Whittington Health National Health Service, London, United Kingdom
7. Academic Department of Critical Care, Portsmouth Hospitals National Health Service Trust, Portsmouth, United Kingdom
8. Centre for Perioperative and Critical Care Research, Imperial College Healthcare National Health Service Trust, London, United Kingdom