1 Unit of Anesthesia, Analgesia and Intensive Care, Department of Surgical and Biomedical Sciences, S. Maria della Misericordia Hospital, Blocco C, University of Perugia, Perugia, Italy - edoardo.derobertis@unipg.it.
2 Department of Anesthesia and Intensive Care Unit, Cardarelli Hospital, Naples, Italy.