1. Anaesthesia and Critical Care Research Group, Division of Clinical Neuroscience, Queen’s Medical Centre, University of Nottingham, Nottingham, UK
2. Department of Anaesthesia, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK
3. Department of Healthcare of Older Life, Nottingham University Hospitals NHS Trust, Nottingham, UK
4. Nottingham University Hospitals NHS Trust, Nottingham, UK
5. Warwick Medical School, University of Warwick, Warwick, UK