[1] Univ Hosp S Orsola Malpighi Policlin, Pediat Intens Care Unit, Dept Woman Child & Urol Dis, Via Albertoni 15, I-40138 Bologna, Italy
[2] Univ Hosp Padua, Pediat Intens Care Unit, Dept Womans & Childs Hlth, Via Giustiniani 2, I-35128 Padua, Italy
[3] Univ Hosp Padua, Dept Cardiac Thorac Vasc Sci & Publ Hlth, Unit Biostat Epidemiol & Publ Hlth, Via Loredan18, I-35131 Padua, Italy
[4] Univ Cattolica Sacro Cuore, Dept Anesthesia & Intens Care, Pediat Intens Care Unit, A Gemelli Policlin, Largo Agostino Gemelli 8, I-00168 Rome, Italy
[5] Univ Cattolica Sacro Cuore, A Gemelli Policlin, Pediat Trauma Ctr, Largo Agostino Gemelli 8, I-00168 Rome, Italy