Nicolas Brogly1,2, Emilia Guasch3. 1. Service of Anesthesia and Intensive Care, La Paz University Hospital, Madrid, Spain - nicolas0brogly@hotmail.com. 2. Service of Anesthesia, La Zarzuela University Hospital, Madrid, Spain - nicolas0brogly@hotmail.com. 3. Service of Anesthesia and Intensive Care, La Paz University Hospital, Madrid, Spain.