Problems in diagnosing nosocomial pneumonia in mechanically ventilated patients: A review

Objective: To review the available information about diagnosing nosocomial pneumonia in mechanically ventilated intensive care unit patients. Data Sources: The National Library of Medicine MEDLINE database and bibliographies of the reviewed articles. Study Selection and Data Extraction: Studies were selected from the English literature, with an emphasis on recent studies. Studies were selected on the basis of their historical value and originality. A total of 82 articles was considered relevant. Data Synthesis: Many efforts have been made to diagnose nosocomial pneumonia with more accuracy. Two promising new diagnostic modalities are the protected specimen brush and bronchoalveolar lavage, both performed via flexible bronchoscopy. Depending on the study design and patient selection, sensitivity and specificity of bronchoalveolar lavage and protected specimen brush differ widely, ranging from 50% to 100%. However, interpretation of study results is seriously hampered because a standardized diagnostic threshold is not available, the influence of previous antimicrobial therapy on culture results remains unclear, and, most importantly, a well-defined gold standard to study the value of both methods is lacking. Conclusions: Because studies of bronchoalveolar lavage and protected specimen brush are seriously hampered by several pitfalls, these studies as well as clinical results must be interpreted with caution.