Fig. 1

Receiver operating curves for hospital mortality at different PEEP thresholds for 3191 patients from our study [1], after excluding those with missing mean airway pressure values. Abbreviations: P/F, ratio of the partial pressure of arterial oxygen (PaO2) to the fraction of inspired oxygen (FiO2); P/FP = (PaO2*10)/(FiO2*PEEP); OI, oxygenation index = (FiO2*MAP)/PaO2; OF, oxygenation factor = (PaO2/(FiO2*MAP); PEEP, positive end-expiratory pressure; AUC, area under the curve; CI confidence interval; NS, not significant