pulmonary disorders
Hospital Acquired Pneumonia
Diagnosis of Hospital Acquired Pneumonia
Chest x-ray or chest computed tomography (CT) and clinical criteria (limited accuracy) Sometimes bronchoscopy or blood cultures Usually, a diagnosis is made based upon a new lung infiltrate combined with clinical features of infection, which include the new onset of fever, purulent sputum, leukocytosis, and decline in oxygenation. However, clinical diagnosis is imperfect. No symptom, sign, or x-ray finding is sensitive or specific for the diagnosis of hospital-acquired pneumonia, because all can be caused by Atelectasis , Gram stain and semiquantitative cultures of sputum samples, though not definitive for identifying infection, should be done because they can direct empiric therapy. Bronchoscopic sampling of lower airway secretions for quantitative culture yields more reliable specimens that can differentiate colonization from infection. Information gained from bronchoscopic sampling reduces antibiotic use and assists in switching from broader to narrower antibiotic coverage. However, it has not been shown to improve outcomes. Measurement of inflammatory mediators in bronchoalveolar lavage fluid or serum has not been shown to be reliable in deciding on initiation of antibiotics. The only finding that reliably identifies both pneumonia and the responsible organism is a pleural fluid culture (obtained via thoracentesis in a patient with pleural effusion) that is positive for a respiratory pathogen. Blood cultures are relatively specific if a respiratory pathogen is identified but are insensitive. Molecular tests that identify the pathogen and resistance patterns in respiratory secretions are emerging and could be useful in guiding treatment. 