New diagnostic approaches to the hospitalized patient with pneumonia.

The accurate diagnosis of pneumonia remains a formidable challenge in clinical medicine. The use of sputum, blood, and pleural fluid cultures provides a diagnosis in less than 50% of patients. A number of invasive techniques have recently been applied to the diagnosis of pneumonia. The methods are uniformly designed to separate upper respiratory saprophytic bacterial populations from the organisms responsible for the lower respiratory infection. Preeminent among these techniques is the use of fiberoptic bronchoscopy coupled with quantitative bacterial culture and immunofluorescence demonstration of antibody-coated bacteria. The methodology and results of this technique are described in detail in this paper. Recent clinical experience using transtracheal aspiration, percutaneous needle aspiration of the lung, and open lung biopsy are also reviewed.