1. Department of Anaesthesiology and Critical Care, Hospital General Universitario De Valencia, Valencia, Spain
2. Department of Anaesthesiology, Rescue- and Pain Medicine, Cantonal Hospital of St. Gallen, St. Gallen
3. Department of Anaesthesiology and Pain Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
4. Department of Anaesthesiology and Critical Care, Hospital General Universitario De Valencia, Valencia, Spain; Research Methods Department, Universidad Europea de Valencia, Valencia, Spain