1. Department of Intensive Care Medicine and Surrey Peri-Operative Anaesthesia and Critical Care Collaborative Research Group, Royal Surrey County Hospital NHS Foundation Trust, Guildford, UK
2. Primary Care and Population Sciences, University of Southampton, Southampton General Hospital, Southampton, UK
3. Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
4. Department of Intensive Care, Guy’s & St Thomas’ NHS Trust, London, UK