Pamela E Macintyre Consultant Anaesthetist; and Director, Acute Pain Service Department of Anaesthesia, Pain Medicine and Hyperbaric Medicine Royal Adelaide Hospital and University of Adelaide Adelaide, Australia Suellen M Walker Clinical Senior Lecturer in Paediatric Anaesthesia and Pain Medicine, UCL Institute of Child Health and Great Ormond Street Hospital NHS Trust, London, UK David J Rowbotham Professor of Anaesthesia and Pain Management; and Head, Clinical Division of Anaesthesia, Critical Care and Pain Management, University of Leicester,