1. Department of Anaesthesia, Resuscitation and Intensive Medicine, 1st Faculty of Medicine and General University Hospital, Charles University in Prague, U Nemocnice 2, 128 08 Prague 2, Czech Republic
2. Third Department of Medicine, 1st Faculty of Medicine and General University Hospital, Charles University in Prague, U Nemocnice 1, 128 08 Prague 2, Czech Republic
3. Department of Cardiac Surgery, 1st Faculty of Medicine and General University Hospital, Charles University in Prague, U Nemocnice 2, 128 08 Prague 2, Czech Republic
4. Institute of Metabolic Science, University of Cambridge, Addenbrooke's Hospital, Box 289, Cambridge CB2 0QQ, UK