Ramai Santhirapala1, Lee A Fleisher2, Michael P W Grocott3. 1. Department of Anaesthesia and Perioperative Medicine, Guy's and St Thomas' NHS Foundation Trust, London, UK; Department of Quality and Policy, Academy of Medical Royal Colleges, London, UK; Department of Surgery and Interventional Science, University College London, London, UK. Electronic address: ramais@doctors.org.uk. 2. Departments of Anesthesiology and Critical Care and Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. 3. Respiratory and Critical Care Research Theme, University Hospitals Southampton-University Hospitals Southampton NIHR Biomedical Research Centre, Southampton, UK; Department of Anesthesiology, Duke University School of Medicine, Durham, NC, USA.