1. Department of Surgery and Anaesthesia; Division of Medical Sciences and Graduate Entry Medicine, School of Medicine, University of Nottingham; Derby UK
2. Centre for Evidence Based Healthcare, Division of Epidemiology and Public Health, Clinical Sciences Building Phase 2; University of Nottingham; Nottingham UK
3. Department of Anaesthesia; Frimley Health NHS Foundation Trust, Frimley Park Hospital; Frimley UK
4. Department of Surgery; Division of Medical Sciences and Graduate Entry Medicine, School of Medicine, University of Nottingham; Derby UK
5. Department of Anaesthesia and Intensive care; Royal Derby Hospital; Derby UK
6. Department of Anaesthesia; University Hospitals of Leicester; Leicester UK
7. Division of Health Sciences, School of Medicine; University of Nottingham; Derby UK