1 University of Florence, Emergency and Trauma Intensive Care Unit, DAI-DEA, Azienda Ospedaliero Universitaria Careggi, Florence, Italy. Electronic address: stebam@hotmail.it.
2 General Intensive Care Unit, Ospedale San Gerardo Monza, Monza, Italy.
3 Intensive Care Unit, Azienda Ospedaliera di Perugia, Perugia, Italy.