1 From the Department of Paediatric Anaesthesia and Critical Care, La Paz University Hospital, Madrid, Spain (PG-P), Division of Anaesthesia, Analgesia, and Intensive Care - Department of Medicine and Surgery - University of Perugia, Ospedale S. Maria della Misericordia, Perugia, Italy (EDR) and Division of Anaesthesiology, Intensive Care and Emergency Medicine, Department of Anaesthesiology, University Medical Center Utrecht, Utrecht, The Netherlands (WB).