1. Department of Cardiology, Angiology and Intensive Care Medicine, Philipps University of Marburg, 35043 Marburg, Germany
2. Department of Obstetrics and Gynecology, Medical University of Plovdiv, 4002 Plovdiv, Bulgaria
3. Department of Anesthesia and Intensive Care Medicine, Philipps University of Marburg, 35043 Marburg, Germany