Sequential measurements of procalcitonin levels in diagnosing ventilator-associated pneumonia

Abstract

The utility of procalcitonin levels to improve the accuracy of clinical and microbiological parameters in diagnosing ventilator-associated pneumonia (VAP) was evaluated.Sequential measurement of procalcitonin and C-reactive protein levels and the calculation of the simplified Clinical Pulmonary Infection Scores (CPIS) were performed in 44 patients mechanically-ventilated for .48 h with neither active infection for the duration or suspicion of VAP. Patients who developed extrapulmonary infection were excluded.In total, 20 cases were suspected of having VAP and diagnosis was microbiologically confirmed in nine. In patients with confirmed VAP, procalcitonin levels were higher than in those without VAP. C-reactive protein levels and CPIS were lower in patients without suspected VAP, but could not discriminate confirmed and nonconfirmed suspicion of VAP. The best sensitivity and specificity (78 and 97%, respectively) corresponded to procalcitonin. The CPIS resulted in the same sensitivity, but had a lower specificity (80%). C-reactive protein had the worst sensitivity (56%), but a good specificity (91%). A CPIS o6 combined with serum levels of procalcitonin o2.99 ng?mL -1 did not improve the sensitivity (67%), but resulted in 100% specificity.Procalcitonin might be useful in the diagnosis of ventilator-associated pneumonia. Combined values of Clinical Pulmonary Infection Scores and procalcitonin below the cut-off points excluded false-positive diagnoses of ventilator-associated pneumonia.

Researching the Changes of Serum Procalcitonin Levels in Ventilator-Associated Pneumonia Patients

“…He found clinical pulmonary infection score ≥6 had 78% sensitivity and 80% specificity. A clinical pulmonary infection score ≥6 combined with serum procalcitonin levels ≥2.99 ng/ml resulted in 100% specificity [12]. According to the guideline of American Thoracic Society [1], there were 63 VAP cases in our study but only 43 VAP cases (68.25%) in the VAP group had serum procalcitonin level >0.5 ng/ml and 20 VAP cases (31.75%) in the VAP group had serum procalcitonin level ≤0.5 ng/ml (Table 2).…”

Plasma Procalcitonin: Another Arrow in Our Quiver?

“…[12][13][14][15] In the only study in which procalcitonin was found to be a good diagnostic marker for VAP, only 20 patients were included and those with a previous infection during the same hospitalization were excluded, limiting the potential value of this marker to a very limited subset of ICU patients. 16 Several factors could explain these results. First, pneumonia may be a localized infection, within which procalcitonin can be synthesized locally without systemic release (as in other such compartmentalized infections), thereby explaining its low serum level or apparent decline in patients with true pulmonary infections.…”

The Role of Bronchoscopic Findings and Bronchoalveolar Lavage Fluid Cytology in Early Diagnosis of Ventilator-Associated Pneumonia

“…Furthermore, modified CPIS lacks sensitivity (Ͻ80%), as described in the present and previous studies focusing on the simplified version of the CPIS. 13,[16][17][18] The relative neutrophil cell count (%) at various cutoff levels did not substantially improve the diagnostic performance of either modified CPIS or Johanson criteria. This result could be partially justified by the absence of a significant difference in neutrophil cell count between subjects with VAP and subjects with another diagnosis.…”