Culturing bronchial washings obtained during bronchoscopy fails to add diagnostic utility to culturing the bronchoalveolar lavage fluid alone.
Diagn Microbiol Infect Dis 2002;43:99–105. Pinckard JK, Kollef M, Dunne WM. Division of Laboratory Medicine, Washington University School of Medicine, St. Louis, MO, U.S.A.
This retrospective analysis was performed to determine whether cultures of bronchial washings (BW) obtained during bronchoscopy added to the diagnostic efficiency of cultures of bronchoalveolar lavage fluid (BAL) alone. The study material included results of BW and BAL cultures from 268 patients over a 7-month period. The mean patient age was 53 years, with a range of 18 to 89 years. The bronchoscopic method used was as follows: Bronchoalveolar lavage was performed using bronchoscopic guidance. All bronchoscopies were administered in a standard manner by attending pulmonary physicians or by pulmonary disease fellows under the supervision of attending physicians. Those patients who did not have an artificial airway in place were intubated using bronchoscopic guidance after first receiving 5 to 10 mL of 3% lidocaine by nebulization. Lidocaine (10 mL, 1% solution) was instilled down the endotracheal tube prior to passage of the bronchoscope. The bronchoscope was then advanced through the endotracheal tube to a specific lung segment until resistance was met (i.e., wedged position). Three aliquots of 50 mL sterile, physiologic saline solution were injected through the channel of the bronchoscope and then recovered using the same syringe. The returns from the last two aliquots of lavage fluid were pooled, yielding the bronchoalveolar lavage sample. Bronchial wash samples were obtained after bronchoalveolar lavage was performed and the bronchoscope was pulled back into a proximal airway. One to three aliquots of 10 mL sterile, physiologic saline solution were injected through the channel of the bronchoscope onto the bronchial airway and then recovered into a sterile container. For the study, computerized pharmacy records were assessed for all patients in the database to determine whether culture results prompted specific treatment changes following bronchoscopic sampling. For example, if cytomegalovirus were identified in cultures of BW but not BAL, subsequent administration of antiviral therapy would be regarded as BW-specific therapy. Many of the patients included in this analysis were either receiving appropriate antimicrobial coverage before bronchoscopy or were placed on empiric antibiotics at presentation but prior to bronchoscopy. For the purpose of this study, however, isolates designated as “treated” refer only to those organisms whose recovery from BW or BAL triggered a change in or addition to existing antimicrobial therapy. The results showed that the isolation of an organism from the BW but not from the BAL occurred in only 17% of cases. Moreover, the vast majority of those organisms consisted of yeasts or molds of questionable clinical significance that did not prompt a change in antimicrobial therapy. Culturing the BAL specimen alone would have resulted in an efficiency of 97% (95% confidence interval, 94.2%–98.7%) for the isolation of clinically relevant pathogens identified from bronchoscopic specimens. These results suggest that the submission of BW obtained during the BAL procedure for culture evaluation not only fails to add diagnostic value, but may also result in unnecessary laboratory evaluations and may provide misleading information to clinicians. I entirely agree with the conclusion from this study. I have taught and written that when BAL is obtained to isolate bacterial pathogens, it is unnecessary to perform both BAL and bronchial washings. Similarly, obtaining both BAL and protected brush specimen is also unnecessary for the isolation of pulmonary bacterial pathogens.