Because all patients with VAP had positive tracheal aspiration cultures, we retrospectively assessed both the original CPIS and the proposed CEPPIS calculation. Positivity at CPIS calculation for VAP diagnosis (total score > 6) was found in 45 patients (39.8%), whereas CEPPIS > 5 identified 91 patients (80.5%) with microbiologically confirmed VAP. Thus, in the microbiologically confirmed VAP group, patients with CEPPIS > 5 had an up to 20-fold increased risk for VAP (OR, 23.78; P < .0001), with a sensitivity of 80.5%, a specificity of 85.2%, a positive predictive value of 85.1%, and a negative predictive value of 80.7% (Table 5). CPIS was also a statistically significant predictor, but patients with microbiologically confirmed VAP showed only a threefold increased risk for VAP at CPIS > 6 (OR, 3.309; P = .0002), with a sensitivity of 39.8%, a specificity of 83.3%, a positive predictive value of 71.4%, and a negative predictive value of 57% (Table 5). Considering that chest echography and procalcitonin levels are the main changes introduced in the score tested and are both well-established modalities in infection diagnosis, we analyzed the predictive power of chest echography and procalcitonin level alone and in combination. As summarized in Table 5, the presence of infiltrates on chest echograph was a statistically significant VAP predictor, with an eightfold increased risk in patients with microbiologically confirmed VAP (OR, 8.011; P < .0001) but with a lower sensitivity than CEPPIS (59.3% vs 80.5%, respectively). On the contrary, procalcitonin level alone was not significantly associated with VAP diagnosis (OR, 0.8571; P = .7369). The combination of chest echography and procalcitonin level was a good predictor for VAP (OR, 6.738; P = .0005), with an improvement in specificity when compared with chest echography alone (94.2% vs 84.6%, respectively), which is lower than CEPPIS but superior compared with CPIS. Finally, the superiority of CEPPIS in the prediction of VAP relative to CPIS, chest echography, and procalcitonin level was confirmed by receiver operating characteristic area under the curve analysis (Table 6).