1. Department of Anaesthesia, Addenbrookes Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
2. Emergency Department, Wexham Park Hospital, Frimley Health NHS Foundation Trust, Slough, UK
3. Nuffield Department of Anaesthesia, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
4. Emergency Department, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
5. Norwich Medical School, University of East Anglia, Norwich, UK
6. Emergency Department, Royal Berkshire Hospital NHS Foundation Trust, Reading, UK