Sixty-one percent of patients (n = 30) receiving NIV survived; duration of NIV was of 8 (2 to 18) hours. There were no differences between survivors and nonsurvivors in the duration of the procedure, or in the type of interface or respirator used. Of note, most patients on NIV (46 out of 49; 94%) had to be intubated and ventilated invasively for hypoxemic failure. Characteristics associated to NIV success/failure are shown in Table 5 .