EVALUATION OF BRONCHOSCOPIC TECHNIQUES FOR THE DIAGNOSIS OF NOSOCOMIAL PNEUMONIA

To compare the usefulness of specimens obtained by bronchoalveolar lav age (BAL) and using a protected specimen brush (PSB) in the diagnosis of nosocomial pneumonia, both procedures were performed via fiberoptic bronchoscopy just after death in a series of 20 ventilated patients w ho had not developed pneumonia before the terminal phase of their dise ase and who had no recent changes in antimicrobial therapy. These resu lts were compared with both histologic and microbiologic postmortem lu ng features in the same area. The total number of bacteria obtained by culture of lung segments and the latters' histologic grade were close ly correlated (p = 0.79, p < 0.0001). PSB and BAL quantitative culture results were strongly correlated with lung tissue values (p = 0.67 an d 0.75, respectively; p < 0.0001). Using discriminative values of grea ter than or equal to 10(3) and greater than or equal to 10(4) bacteria /g to define positive PSB and BAL cultures, respectively, these techni ques identified lung segments yielding greater than or equal to 10(4) bacteria/g tissue with sensitivities of 82 and 91% and specificities o f 89 and 78%, respectively. Moreover, upon direct observation, the per centage of BAL cells containing intracellular bacteria was closely cor related with the total number of bacteria obtained from corresponding lung samples (p < 0.001). These findings indicate that bronchoscopic P 58 and BAL samples very reliably identify both qualitatively and quant itatively microorganisms present in lung segments with bacterial pneum onia, even when the infection develops as a superinfection in a patien t already receiving antimicrobial treatment for several days.