1. Department of Anesthesiology, Intensive Care Medicine and Pain Medicine; Saarland University; University Medical Center; Homburg/Saar Germany
2. Institute for Medical Biometry, Epidemiology and Medical Informatics; Saarland University; University Medical Center; Homburg/Saar Germany
3. Department of Anesthesiology and Intensive Care; Jena University Hospital; Jena Germany
4. Department of Anaesthesiology, Intensive Care and Pain Medicine; University Hospital Knappschaftskrankenhaus; Ruhr-University Bochum; Bochum Germany