1. Department of Gastroenterology; Maastricht University Medical Center; Maastricht The Netherlands
2. Department of Anaesthesiology; Maastricht University Medical Center; Maastricht The Netherlands
3. Department of Anaesthesiology; Oost Limburg Hospital; Genk Belgium
4. Department of Clinical Epidemiology and Medical Technology Assessment; Maastricht University Medical Center; Maastricht The Netherlands