1. Intensive Care Unit, Hospital Universitario de Canarias, Santa Cruz de Tenerife, Spain.
2. Intensive Care Unit, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain.
3. Department of Physiology, Faculty of Medicine, University of the La Laguna, Santa Cruz de Tenerife, Spain.
4. Intensive Care Unit, Hospital General La Palma, La Palma, Spain.
5. Intensive Care Unit, Hospital Clínico Universitario de Valencia, Valencia, Spain.
6. Intensive Care Unit, Hospital Insular, Las Palmas de Gran Canaria, Spain.
7. Intensive Care Unit, Hospital Universitario Dr. Negrín, Las Palmas de Gran Canaria, Spain.
8. Research Unit, Hospital Universitario de CanariasSanta Cruz de Tenerife. Spain.