[The usefulness of elastin fibers as a diagnostic marker in ventilator-related pneumonia]

The diagnosis of nosocomial pneumonia is especially difficult in intubated patients due to the low specificity of their clinico-radiological signs. The objective of this study was to evaluate the usefulness of basing diagnosis on elastin fibers (EF) in bronchoaspirate (BAS) as an indication of pneumonia in mechanically-ventilated (MV) patients. Forty-seven MV patients suspected of having nosocomial pneumonia were studied prospectively. Fiber bronchoscopy was carried out on all patients and samples were obtained using a protected catheter brush (PCB) and bronchoalveolar lavage (BAL). A purulent sample of BAS was also examined, after addition of 40% KOH, to determine the presence of EF. EF was found in 15 patients, 11 of whom had pneumonia while 3 more had necrotizing pneumonia (sensitivity 52%, specificity 85%). Ten of the 17 microorganisms isolated in the cases of EF positive pneumonia were gram negative, although the germ found most often was S. aureus. There were no differences in the prognosis for pneumonia patients who were EF positive and those who were EF negative. In conclusion, once necrotizing pneumopathology has been ruled out, the presence of EF in BAS may offer reasonable support for firm diagnosis in some MV patients with pneumonia.