1 From the Department of Anaesthesia and Pain Medicine, Birmingham Children's Hospital, Birmingham, UK (K-CT), Department of Neurosciences, Reproductive and Odontostomatological Sciences, University of Naples "Federico II", Napoli, Italy (EDR), Department of Anaesthesiology and Intensive Care Medicine, University Hospital of Cologne, Cologne, Germany (BWB) and Department of Anaesthesia and Intensive Care, Baerum Hospital, Sandvika, Norway (JM-O).