[1] Mario Negri Inst Pharmacol Res, Dept Publ Hlth, Lab Mother & Child Hlth, I-20156 Milan, Italy
[2] Univ Turin, San Giovanni Battista Molinette Hosp, Dept Anesthesiol & Intens Care Med, Turin, Italy
[3] Regina Margherita Univ, Childrens Hosp, Pulmonol Unit, Turin, Italy
[4] Bambino Gesu Childrens Res Hosp, Resp Unit, Rome, Italy
[5] G Gaslini Inst Children, Anesthesiol & Intens Care Med Unit, Genoa, Italy
[6] Vittore Buzzi Childrens Hosp, Dept Anesthesiol & Intens Care, Milan, Italy
[7] Santobono Hosp, Intens Care Unit, Naples, Italy