The Role of Bronchoscopic Findings and Bronchoalveolar Lavage Fluid Cytology in Early Diagnosis of Ventilator-Associated Pneumonia

BACKGROUND: Early diagnosis of ventilator-associated pneumonia (VAP) is necessary to reduce morbidity and improve survival of critically ill patients in the ICU. The purpose of the present study is to examine the performance of macroscopic bronchoscopic findings and cytological analysis of bronchoalveolar lavage fluid (BALF) as an early diagnostic tool for VAP, either alone or in combination with clinically oriented scores (modified Clinical Pulmonary Infection Score [CPIS] or Johanson criteria). METHODS: BAL was performed in 54 consecutive mechanically ventilated subjects. The predictive value of isolated or combined clinical characteristics, BALF, and/or other laboratory measurements in diagnosing VAP was analyzed by logistic regression analysis. A separate diagnostic score was derived from a linear combination of independent variables included in the multivariate model and compared with CPIS, Johanson criteria, and their combinations with BALF cytology (receiver operating characteristic curve analysis). RESULTS: Integrating relative neutrophil cell count in CPIS or Johanson criteria optimized their specificity (>80%) but decreased sensitivity (<70%). Radiographic progression and the presence of distal purulent secretions on bronchoscopy were independently associated with VAP diagnosis. A new score that incorporates clinical, radiographic, and early bronchoscopic findings presented excellent diagnostic accuracy (area under curve = 0.96, sensitivity 94.3%, specificity 84.2%). CONCLUSIONS: The diagnostic performance of classical clinical scores for VAP did not improve after combination with BALF cytology. A new composite score proved to be more accurate than previous scores in early VAP diagnosis.