1. Department of Anaesthesia and Intensive Care, Santa Maria degli Angeli Hospital, Via Montereale 24, 33170 Pordenone, Italy.
2. Department of Anaesthesiology, University of Parma, 43100 Parma, Italy.
3. Department of ENT, Santa Maria degli Angeli Hospital, Via Montereale 24, 33170 Pordenone, Italy.