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Ventilator-associated pneumonia in injured patients: do you trust your Gram's stain?

Kimberly A Davis1, Matthew J Eckert, R Lawrence Reed

  • 1Department of Surgery, Division of Trauma, Surgical Critical Care and Burns, Loyola University Medical Center, Maywood, Illinois 60153, USA. kdavis3@lumc.edu

The Journal of Trauma
|March 12, 2005
PubMed
Abstract

Insights

Gram

Area of Science:

  • Critical Care Medicine
  • Infectious Diseases
  • Microbiology

Background:

  • Sputum or bronchoalveolar lavage (BAL) fluid Gram's stain is used to guide antibiotic therapy for ventilator-associated pneumonia (VAP) in injured patients.
  • The diagnostic accuracy of Gram's stain for VAP is variable, impacting its clinical utility.
  • Evaluating the effectiveness of Gram's stain in diagnosing VAP is crucial for optimizing patient care.

Purpose of the Study:

  • To assess the diagnostic utility of Gram's stain of BAL fluid in identifying VAP in mechanically ventilated trauma patients.
  • To determine the accuracy of Gram's stain in identifying specific organisms causing VAP.

Main Methods:

  • Retrospective chart review of 155 mechanically ventilated trauma patients diagnosed with VAP over a 5-year period.
  • Analysis of Gram's stain results alongside final culture data for VAP diagnosis.
  • VAP diagnosis confirmed by Centers for Disease Control and Prevention criteria and quantitative BAL culture.

Main Results:

  • Overall accuracy of Gram's stain for detecting any organism in VAP was 88%.
  • Accuracy decreased when identifying specific organisms: 63% for Gram-negative and 72% for Gram-positive VAP.
  • Absence of Gram-positive organisms on Gram's stain excluded Gram-positive VAP in 80% of cases.

Conclusions:

  • Gram's stain may aid in the early diagnosis of VAP due to its overall accuracy in detecting any organism.
  • Gram's stain is not reliable for guiding presumptive antibiotic therapy due to limited accuracy in identifying specific pathogens.
  • Presumptive coverage for Gram-negative organisms is recommended, as they cause 70% of VAP infections but are not reliably identified by Gram's stain.

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