1. Department of Anaesthesiology; VU University Medical Center; Institute for Cardiovascular Research; Amsterdam the Netherlands
2. Department of Anaesthesiology; Westfriesgasthuis; Hoorn the Netherlands
3. Department of Anaesthesiology; Spaarneziekenhuis; Hoofddorp the Netherlands
4. Department of Anaesthesiology; Medical Center Alkmaar; Alkmaar the Netherlands