Table 6. Cut-off points of APACHE II, blood glucose, and fentanyl, and the corresponding sensitivity, specificity, PPV, NPV, and LR in distinguishing extubation failure in patients with severe pneumonia.
| Cut-off point | Sensitivity (%) | Specificity (%) | PPV (%) | NPV (%) | LR+ | LR- | |
|---|---|---|---|---|---|---|---|
| APACHE II | 17.5 | 62.79 | 69.51 | 51.92 | 78.08 | 2.06 | 0.54 |
| Blood glucose (mmol/l) | 9.87 | 41.86 | 71.95 | 43.90 | 70.24 | 1.49 | 0.81 |
| Fentanyl (mg/d) | 1.135 | 37.21 | 85.37 | 57.14 | 72.16 | 2.54 | 0.74 |
APACHE II, acute physiology, age, chronic health evaluation; LR, likelihood ratio; NPV, negative predictive value; PPV, positive predictive value.