[1] Univ Catania, Dept Cin & Expt Med, Catania, Italy
[2] Policlin G Rodol San Marco Univ Hosp, Resp Med Unit, Catania, Italy
[3] Univ Palermo, Dept Surg, Palermo, Italy
[4] Univ Palermo, Dept Oncol & Oral Sci, Palermo, Italy
[5] Policlin Paolo Giaccone, Dept Anesthesia Intens Care & Emergency, Palermo, Italy
[6] Univ Catania, Policlin G Rodol San Marco Univ Hosp, Dept Clin & Expt Med, Resp Med Unit, Via S Sofia,78, I-95123 Catania, Italy