Pedro Gambus is a consultant anaesthetist at the Hospital CLINIC de Barcelona and Associate Professor of Biomedical Engineering at the Universitat de Barcelona, former postdoctoral fellow at the Department of Anesthesia at Stanford University, California, and Visiting Professor at the Department of Anesthesia and Perioperative Care University of California in San Francisco (UCSF). Jan Hendrickx is a consultant anaesthetist at Aalst General Hospital and Adjunct Professor at the Department of Anesthesia at Stanford University, California.