1. Department of Anaesthesiology and Surgical Intensive Care, Hospital Universitario de la Princesa, Diego de León 62, 28006 Madrid, Spain
2. Departament of Preventive Medicine and Public Health, Hospital Universitario de la Princesa, Diego de Leon 62, 28006 Madrid, Spain
3. Teaching Unit of Anesthesiology and Critical Pathology, Faculty of Medicine, University of Valladolid, 47003 Valladolid, Spain
4. Departament Anesthesiology and Surgical Intensive Care, Valladolid University Clinical Hospital, 47003 Valladolid, Spain
5. Department of Anaesthesiology and Surgical Intensive Care, Hospital del Mar, Passeig Marítim 25-29, 08003 Barcelona, Spain
6. Department of Anaesthesiology and Surgical Intensive Care, Hospital QuirónSalud Valle del Henares, Constitution Avenue, 249, Torrejon de Ardoz, 28850 Madrid, Spain
7. Departament of Clinical Analysis, Hospital Universitario de la Princesa, Diego de Leon 62, 28006 Madrid, Spain
8. Department of Anaesthesiology, Infanta Leonor University Hospital, Gran Via del Este 80, 28031 Madrid, Spain