Table 6.
Receiver operating curves parameters
| AU-ROC (95% CI) | Best cut-off value* | Sensitivity | Specificity | PPV | NPV | |
|---|---|---|---|---|---|---|
| Single VAP diagnostic parameter | ||||||
| IL-10 (log10 pg/L) | 0.71 (0.47–0.96) | 0.250 | 80% | 70% | 73% | 78% |
| TNF-α (log10 pg/L) | 0.69 (0.44–0.96) | − 0.190 | 89% | 56% | 67% | 83% |
| Tracheal secretion P. aeruginosa concentration (cfu/mL) | 0.80 (0.58–1.00) | 6.34 | 70% | 90% | 88% | 75% |
| Tracheal secretion P. aeruginosa concentration scorea | 0.71 (0.50–0.92) | 4 | 80% | 60% | 67% | 75% |
| Combined VAP diagnostic parameterb | ||||||
| IL-10 + tracheal secretion P. aeruginosa concentration scorea | 0.78 (0.58–0.99) | 5 | 70% | 80% | 78% | 78% |
| TNF-α + tracheal secretion P. aeruginosa concentration scorea | 0.73 (0.51–0.95) | 5 | 78% | 67% | 70% | 75% |
| IL-10 + TNF-α + tracheal secretion P. aeruginosa concentration scorea | 0.82 (0.61–1.00) | 6 | 67% | 89% | 86% | 73% |
*Receiver operating curves of ventilator-associated pneumonia diagnostic parameters and their combination. *The optimal cut-off values were computed through the Youden’s index (J), which is the maximal vertical distance between the ROC curve and the first bisector (or chance line)
aThe tracheal secretion P. aeruginosa concentration score was computed as follows: 0: < 3.0 log cfu/mL; 1: 3.0–3.9 log cfu/mL; 2: 4.0–5.9 log cfu/mL; 3: 5–6 log cfu/mL; 4: > 6 log cfu/mL. AU-ROC area under receiver operating curve, CI confidence interval, PPV positive predictive value, NPV negative predictive value, IL interleukin, TNF tumor necrosis factor
bTo combine interleukins and tracheal secretion P. aeruginosa concentration score, we categorized IL-10 and TNF-α as 0–1 values, based on the best cut-off value