title: The value of pretest probability and modified clinical pulmonary infection score to diagnose ventilator-associated pneumonia.
abstract: OBJECTIVE
  The aim of the study was to assess the utility of pretest probability and modified clinical pulmonary infection score CPIS in the diagnosis of late-onset ventilator-associated pneumonia (VAP).
  
  
  METHODS
  In 740 adults enrolled in a multicenter randomized trial, intensivists prospectively rated the pretest probability of VAP as low, moderate, or high based on their clinical judgment. The modified CPIS was calculated without considering culture results. Ventilator-associated pneumonia diagnosis was determined by 2 adjudicators using standardized definitions. We analyzed the relationship between pretest likelihood, CPIS, and VAP diagnosis.
  
  
  RESULTS
  Among the 739 patients analyzed, 14.5%, 39.6%, and 45.9% had low, moderate, and high pretest probability of VAP. Patients with high pretest probability had a lower PaO2/FiO2 ratio and a larger volume of secretions. High or moderate vs low pretest probability had high sensitivity (0.88; 95% confidence interval [CI], 0.87-0.89) and positive predictive value (0.87; 95% CI, 0.86-0.88) but low specificity (0.27; 95% CI, 0.21-0.35) and negative predictive value (0.29; 95% C,: 0.22-0.37) for the diagnosis of VAP. Therefore, 71% of patients who had a low pretest probability were actually infected (1 - negative predictive value). The area under the receiver operating characteristic curve for the modified CPIS was not significant (0.47; 95% CI, 0.42-0.53), meaning that no score threshold was clinically useful.
  
  
  CONCLUSIONS
  Pretest probability and a modified CPIS, which excludes culture results, are of limited utility in the diagnosis of late-onset VAP.
authors: Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
authors: François
authors: F
authors: Lauzier
authors: Annie
authors: A
authors: Ruest
authors: Deborah
authors: D
authors: Cook
authors: Peter
authors: P
authors: Dodek
authors: Martin
authors: M
authors: Albert
authors: Andrew F
authors: AF
authors: Shorr
authors: Andrew
authors: A
authors: Day
authors: Xuran
authors: X
authors: Jiang
authors: Daren
authors: D
authors: Heyland
mesh_terms: D000704:Analysis of Variance; D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D016009:Chi-Square Distribution; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D053717:Pneumonia, Ventilator-Associated / Q000175:diagnosis* / Q000382:microbiology; D011237:Predictive Value of Tests; D011336:Probability; D012372:ROC Curve; D012680:Sensitivity and Specificity
chemical_list: D000900:Anti-Bacterial Agents