1. Department of Anaesthesia, Whipps Cross Hospital, London, UK
2. Department of Anaesthesia, Royal Free Hospital, London, UK
3. Department of Anaesthesia, University Hospitals Sussex NHS Foundation Trust, Brighton, UK
4. Department of Anaesthesia, Queen Elizabeth Hospital, Gateshead, UK
5. London Health Sciences Centre, Western University, London, Canada
6. Department of Anaesthesia, Medway Maritime Hospital, Gillingham, Kent, UK
7. Centre for Perioperative Medicine, University College London, London, UK
8. Department of Anaesthesia, University College London Hospital, London, UK