title: Influence of antibiotic therapy on the cytological diagnosis of ventilator-associated pneumonia.
abstract: OBJECTIVE
  To assess the influence of antibiotics on the value of various cytological parameters, and their combinations, in diagnosing ventilator-associated pneumonia (VAP).
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  The general intensive care unit (17 beds) of the University Hospital Maastricht.
  
  
  METHODS
  Three hundred and thirty-five episodes of clinically suspected VAP (defined by the clinical and radiological criteria previously described by Bonten et al.) in 282 patients were studied.
  
  
  METHODS
  No additional interventions were conducted.
  
  
  RESULTS
  Bronchoalveolar lavage fluid cytology included a total cell count per millilitre, differential cell count and the percentage of infected cells (cells containing phagocytised organisms). Antibiotic therapy from 72 h prior to lavage was recorded. Areas under the curve (AUCs) of receiver operating characteristic curves were calculated for various cytological parameters and their combinations, in patients with and without antibiotic therapy. In 126 episodes (37.6%) in 106 patients, VAP was confirmed. There was no difference in AUCs between patients with and without antibiotic therapy for any parameter studied. The most prominent AUCs were (for patient groups with and without antibiotics combined): total cell count, 0.65; percentage polymorphonuclear neutrophils, 0.71; and percentage infected cells, 0.90. The combination of percentage infected cells with any other cytological parameter did not increase the AUC.
  
  
  CONCLUSIONS
  Antibiotic therapy did not influence the predictive value of the percentage infected cells in BALF in diagnosing VAP.
authors.affiliation: Department of Medical Microbiology, University Hospital Maastricht, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands. klin@lmib.azm.nl
authors.forename: Catharina F M
authors.initials: CF
authors.lastname: Linssen
authors.forename: Jan A
authors.initials: JA
authors.lastname: Jacobs
authors.forename: Jan S A G
authors.initials: JS
authors.lastname: Schouten
authors.forename: Walther N K A
authors.initials: WN
authors.lastname: van Mook
authors.forename: Graham
authors.initials: G
authors.lastname: Ramsay
authors.forename: Marjolein
authors.initials: M
authors.lastname: Drent
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology* / Q000382:microbiology; D016022:Case-Control Studies; D015169:Colony Count, Microbial; D005260:Female; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D053717:Pneumonia, Ventilator-Associated / Q000175:diagnosis* / Q000188:drug therapy*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D015203:Reproducibility of Results
chemical_list: D000900:Anti-Bacterial Agents