[1] Univ Catania, Dept Clin & Expt Med, Piazza Univ 2, I-95125 Catania, Italy
[2] Policlin G Rodolico San Marco Univ Hosp, Resp Med Unit, Via S Sofia 78, I-95123 Catania, Italy
[3] Univ Palermo, Dept Precis Med Med Surg & Crit Care, Palermo, Italy
[4] Univ Palermo, Dept Anesthesia Intens Care & Emergency, Policlin Paolo Giaccone, Palermo, Italy