title: Alveolar and serum procalcitonin: diagnostic and prognostic value in ventilator-associated pneumonia.
abstract: BACKGROUND
  The potential role of serum and alveolar procalcitonin as early markers of ventilator-associated pneumonia (VAP) and its prognostic value were investigated.
  
  
  METHODS
  Ninety-six patients with a strong suspicion of VAP were prospectively enrolled. VAP diagnosis was based on a positive quantitative culture obtained via a mini-bronchoalveolar lavage of 103 colony-forming units/ml or more. Blood and alveolar samples were collected for procalcitonin measurement and analyzed for diagnostic and prognostic evaluation on days 0, 3, and 6. Sensitivity, specificity, positive likelihood ratio, and receiver-operating characteristic curves were analyzed to define ideal cutoff values and approach the decision analysis.
  
  
  RESULTS
  Serum procalcitonin was significantly increased in the VAP group (n = 44) compared with the non-VAP group (n = 52): 11.5 ng/ml (95% confidence interval, 5.9-17.0) versus 1.5 ng/ml (1.1-1.9). A serum procalcitonin concentration greater than 3.9 ng/ml (best cutoff value) was considered positive for the VAP diagnosis (sensitivity, 41%; specificity, 100%). Serum procalcitonin was significantly increased in the non-survivors compared with the survivors for the VAP group: 16.5 ng/ml (95% confidence interval, 8.1-24.9) versus 2.9 ng/ml (1.2-4.7). The best cutoff value for serum procalcitonin of the nonsurvivors in the VAP group was 2.6 ng/ml (sensitivity, 74%; specificity, 75%; positive likelihood ratio, 2.96). Regarding VAP diagnosis and prognosis, no significant differences were found for alveolar procalcitonin in all groups.
  
  
  CONCLUSIONS
  Serum but not alveolar procalcitonin seems to be a helpful parameter in the early VAP diagnosis and an appropriate marker for predicting mortality.
authors.affiliation: Department of Anesthesiology, Hôpital de l'Hôtel-Dieu, Lyon, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Duflo
authors.forename: Richard
authors.initials: R
authors.lastname: Debon
authors.forename: Guillaume
authors.initials: G
authors.lastname: Monneret
authors.forename: Jacques
authors.initials: J
authors.lastname: Bienvenu
authors.forename: Dominique
authors.initials: D
authors.lastname: Chassard
authors.forename: Bernard
authors.initials: B
authors.lastname: Allaouchiche
mesh_terms: D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D002116:Calcitonin / Q000032:analysis* / Q000097:blood; D015740:Calcitonin Gene-Related Peptide; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000502:physiology; D008297:Male; D008875:Middle Aged; D011014:Pneumonia / Q000175:diagnosis* / Q000378:metabolism / Q000401:mortality; D011379:Prognosis; D011498:Protein Precursors / Q000032:analysis* / Q000097:blood; D011650:Pulmonary Alveoli / Q000737:chemistry*; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology; D012122:Ventilators, Mechanical / Q000009:adverse effects*
chemical_list: C000606589:CALCA protein, human; D015850:Interleukin-6; D011498:Protein Precursors; D014409:Tumor Necrosis Factor-alpha; D002116:Calcitonin; D015740:Calcitonin Gene-Related Peptide