Evaluation of new diagnostic technologies: bronchoalveolar lavage and the diagnosis of ventilator-associated pneumonia.

OBJECTIVE: To present criteria to aid intensive care workers in the assessment of diagnostic technologies, using the example of bronchoalveolar lavage for the evaluation of ventilator-associated pneumonia. DATA SOURCES: MEDLINE was used to search for articles published from 1969 to the present that concerned diagnostic tests, diagnostic technology, pneumonia, and critically ill patients. STUDY SELECTION: Clinical investigations, case control studies, case series, and experimental data on the use of bronchoalveolar lavage. Studies of diagnostic technology were also included. DATA EXTRACTION: We extracted relevant data in duplicate, independently. DATA SYNTHESIS: Diagnostic technology assessment should begin by establishing the capability of the technology under ideal or laboratory conditions, followed by an exploration of the range of possible uses as well as the accuracy of the test. Bronchoalveolar lavage is a well-established technology for the diagnosis of pneumonia in immunocompromised patients. Studies of the accuracy of bronchoalveolar lavage in ventilator-dependent but nonimmunocompromised patients have shown promising diagnostic accuracy. Accuracy, however, is insufficient for dissemination of a test; an evaluation of the impact of a test on management decisions and, most importantly, on patient outcome, is required. Investigators have not addressed the full impact of bronchoalveolar lavage, and, even if the test is accurate, there are reasons to doubt whether patients will be better off if the test becomes part of routine clinical practice.
CONCLUSIONS: We present guidelines for the assessment of diagnostic technology, and apply them to bronchoalveolar lavage for the evaluation of ventilator-associated pneumonia. Bronchoalveolar lavage has been studied in both the laboratory and clinical setting, and the diagnostic sensitivity and specificity of this technique are high. Further randomized trials evaluating management decisions and patient benefit would facilitate decisions regarding the appropriate dissemination of bronchoalveolar lavage.