1 Department of Anaesthesia, Critical Care and Pain Medicine, Royal Infirmary of Edinburgh, Edinburgh, UK. Electronic address: Michael.Gillies@ed.ac.uk.
2 Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada; Department of Anesthesia, Toronto General Hospital, University of Toronto, Toronto, ON, Canada.
3 Surgical Informatics, Centre for Medical Informatics, University of Edinburgh, Royal Infirmary of Edinburgh, Edinburgh, UK.