1. Philips Research, 5656 AE Eindhoven, The Netherlands
2. Department Biomedical Engineering, Eindhoven University of Technology, 5612 AE Eindhoven, The Netherlands
3. Department of Clinical Chemistry, Catharina Hospital, 5602 ZA Eindhoven, The Netherlands
4. Department of Anaesthesiology, Catharina Hospital, 5602 ZA Eindhoven, The Netherlands
5. Department of Electrical Engineering, Eindhoven University of Technology, 5612 AE Eindhoven, The Netherlands