From the Nuffield Division of Anaesthetics, University of Oxford, John Radcliffe Hospital, Headley Way, Oxford, UK (PF), Department of Paediatric and Obstetric Anaesthesia, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark (AA), Department of Anaesthesiology, Intensive Care, Emergency and Pain Medicine. University Hospital Würzburg, Würzburg, Germany (PK), Department of Anaesthesia, Intensive Care and Pain Medicine. General University Hospital. Universidad Europea de Valencia, Valencia, Spain (CSR)

Correspondence to Pierre Foex, Nuffield Division of Anaesthetics, John Radcliffe Hospital, University of Oxford, Headley Way, Oxford OX3 9DU, UK. E-mail: [email protected]