1 Department of Cardiovascular and Thoracic Surgery, Heart and Diabetes Center NRW, Ruhr University Bochum, Bad Oeynhausen, Germany.
2 Department of Anaesthesiology and Pain Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland. Electronic address: gabor.erdoes@insel.ch.
3 Institute of Anesthesiology and Pain Therapy, Heart and Diabetes Center NRW, Ruhr University Bochum, Bad Oeynhausen, Germany.
4 Department of Cardiovascular Surgery, University Heart Center Freiburg, Freiburg, Germany.