1 Department of Anaesthesia and Intensive Care, AOU Policlinico-San Marco, University of Catania, Catania, Italy. Electronic address: filipposanfi@yahoo.it.
2 Department of Anaesthesia and Intensive Care, AOU Policlinico-San Marco, University of Catania, Catania, Italy.
3 Department of Anaesthesia and Intensive Care, University "Magna Graecia", Catanzaro, Italy.