Bilateral versus unilateral bronchoalveolar lavage for the diagnosis of ventilator-associated pneumonia.

Background: Ventilator-associated pneumonia (VAP) complicates the clinical course of critically injured intubated patients. Bronchoscopic bronchoalveolar lavage (BAL) represents an invasive and accurate means of VAP diagnosis. Unilateral and blinded techniques offer less invasive alternatives to bronchoscopic BAL. This study evaluated clinical criteria as well as unilateral directed versus bilateral BAL for VAP diagnosis.

Methods: A retrospective chart review of 113 consecutive intubated trauma patients with clinically suspected VAP undergoing unilateral versus bilateral BAL was performed with comparison of positive culture results (>10(4) colony-forming units [CFU]/mL). Culture results were compared with chest radiograph (CXR) infiltrates and white blood cell (WBC) count elevation.

Results: Bilateral BAL was more likely to be positive than unilateral BAL (50.4% vs. 25.5%). In 37.1% of bilateral BALs, there was discordance between the sides of positivity or the bacteria isolated. A CXR infiltrate and WBC count elevation did not predict positive BAL.

Conclusions: Clinical indicators of VAP are inaccurate, and bilateral bronchoscopic BAL is more likely than unilateral BAL to provide a positive sample in intubated trauma patients. Techniques that do not sample both lungs reliably should be avoided for diagnosis in this patient population.