Appraisal of systemic inflammation and diagnostic markers in a porcine model of VAP: secondary analysis from a study on novel preventive strategies

Intensive Care Medicine Experimental

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 score^a	0.71 (0.50–0.92)	4	80%	60%	67%	75%
Combined VAP diagnostic parameter^b
IL-10 + tracheal secretion P. aeruginosa concentration score^a	0.78 (0.58–0.99)	5	70%	80%	78%	78%
TNF-α + tracheal secretion P. aeruginosa concentration score^a	0.73 (0.51–0.95)	5	78%	67%	70%	75%
IL-10 + TNF-α + tracheal secretion P. aeruginosa concentration score^a	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