Prediction of invasive mechanical ventilation by oxygenation indices and CURB-65
| Se (%) | Sp (%) | PPV (%) | NPV (%) | LR+ | LR− | AUROC | 95% CI | P value | |
| PaO2:FiO2 | 77.2 | 54.8 | 16.5 | 95.5 | 1.72 | 0.41 | 0.70 | 0.62 to 0.78 | <0.001 |
| A/a gradient | 56.6 | 88.5 | 36.1 | 94.6 | 4.90 | 0.49 | 0.10 | 0.61 to 0.78 | <0.001 |
| a/A index | 75.0 | 58.8 | 17.3 | 95.3 | 1.82 | 0.43 | 0.68 | 0.59 to 0.77 | <0.001 |
| ROX index from SpO2 | 77.8 | 62.4 | 19.3 | 96.0 | 2.07 | 0.36 | 0.73 | 0.67 to 0.79 | <0.001 |
| CURB-65 | 13.6 | 94.1 | 22.2 | 89.8 | 2.29 | 0.92 | 0.52 | 0.45 to 0.59 | 0.030 |
A/a gradient, alveolar-arterial oxygen gradient; a/A index, arterial-alveolar oxygen tension ratio; AUROC, area under the curve of receiver operating characteristics; CURB-65, confusion, urea level, respiratory rate, systolic or diastolic blood pressure, 65 years or older; LR−, likelihood ratio of a negative test; LR+, likelihood ratio of a positive test; NPV, negative predictive value ; PaO2:FiO2, ratio of arterial oxygen pressure to fraction of inspired oxygen; PPV, positive predictive value; ROX index, Respiratory rate-OXygenation index; Se, sensitivity; Sp, specificity; SpO2, oxygen saturation.