Bronchoalveolar Lavage

Robert P. Baughman, M.D., Ulrich Costabel, M.D., Keith C. Meyer, M.D.

The concept of alveolar sampling of the distal lung using large volumes of saline originated with the use of whole lung lavage. It was originally performed through the rigid bronchoscope as a treatment for various conditions, including asthma, cystic fibrosis, and alveolar proteinosis. Eventually, it was recognized that directed sampling of the respiratory tract could be performed using a Metras catheter. Subsequently, a series of studies by Finley and coworkers demonstrated that segmental lavage could be used to study cellular and acellular components of the lung lining fluid.[1] [2] This group also used this technique to diagnose pneumocystis pneumonia and pulmonary hemorrhage.[3] [4] As with many other applications of clinical bronchoscopy, the rigid bronchoscope was eventually replaced by the flexible fiberoptic bronchoscope.

In 1974, Drs. Reynolds and Newball published the classic description of performing bronchoalveolar lavage (BAL) using a flexible fiberoptic bronchoscope,[5] and. BAL was quickly identified as a relatively safe method to sample a large portion of the distal lung airspaces. BAL evolved over the following 3 decades from a research tool to a standard diagnostic clinical procedure,[6] and a series of meetings over the past 20 years has been devoted entirely to BAL, with the 10th international congress on BAL held in Coimbra, Portugal, in June 2006. The host for that meeting, Dr. Carlos Robalo Cordeiro, has provided an article for this issue of Seminars in Respiratory and Critical Care Medicine.

This journal issue provides the clinician with an understanding of the role of BAL in current clinical practice. The most important aspect of any procedure is to perform it in a manner that is adequate and reproducible. Dr. Baughman has reviewed several important technical aspects of BAL and provides recommendations for a standard procedure by summarizing several of the prior recommendations that have been previously published.[7] [8] [9] In particular, Dr. Baughman attempts to reconcile prior recommendations made by a variety of groups and investigators in various parts of the world.

BAL has been widely used to evaluate various interstitial lung diseases. Dr. Drent and colleagues review the use of BAL in the diagnosis and management of sarcoidosis. BAL has provided many valuable insights into this disease, including the important observation that the inflammatory reaction of sarcoidosis can be quite intense in the lung yet not accompanied by similar inflammatory changes in peripheral blood.[10]

In the evaluation of other interstitial lung diseases, BAL has had a variable impact. Dr. Nagai et al discuss the use of BAL in evaluating idiopathic interstitial lung diseases, and Dr. Carlos Robalo Cordeiro and colleagues examine the use of BAL in various occupational lung diseases, especially those characterized by interstitial lung disease. Finally, Dr. Costabel et al summarize the value of BAL in assessing other forms of interstitial lung disease.

Infection is the most common reason for performing BAL in clinical practice, and BAL has been shown to be very useful in diagnosing infections in immunocompromised patients.[11] When it was reported that BAL could be used to diagnose bacterial infection,[12] the technique was adapted to diagnose ventilator-associated pneumonia.[13] Dr. Torres and colleagues examine and summarize the role of BAL in diagnosing respiratory infections.

Although BAL can be used to diagnose malignancy, many centers fail to use this important technique as frequently as they should. Dr. Poletti and colleagues provide compelling evidence for the value of BAL in this area.

The final two articles of this issue summarize the overall role of BAL in clinical settings and for research purposes. Dr. Meyer discusses the use of BAL as a diagnostic tool, especially in evaluating interstitial lung disease, and Drs. Rose and Knox provide examples of the use of BAL as a research tool.

Although BAL was originally developed as a research tool, its utility as a clinical tool has led to its widespread use by almost every practicing pulmonologist throughout the world. Given the large area sampled by lavage and the relative safety of the technique, one can only assume that BAL will continue to serve as a useful tool for research, diagnosis, and management. However, care must be made to ensure that the retrieved samples are useful. Applying simple guidelines to obtaining and that the analytical data obtained are reliable and accurate, handling, and analyzing the sample will enhance the diagnostic value of BAL. This will ensure that targeted airspaces are sampled adequately and that the retrieved cellular and acellular components of epithelial surface liquid are processed and analyzed correctly. As newer analytical techniques for the analysis of gene expression via the characterization of nucleic acid and protein profiles in complex biological specimens such as BAL evolve, BAL may become even more useful as a clinical tool for the diagnosis and management of patients with a variety of lung disorders in addition to its utility as a research tool.

The guest editors want to thank the contributors for taking the time and effort to complete this journal issue. We would also like to thank Anita Kaufman of Thieme Medical Publishers for her help and patience. Finally, we all wish to thank Dr. Joseph Lynch for his support and helpful suggestions in the preparation of this issue.

REFERENCES

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• 13 Torres A, El-Ebiary M. Bronchoscopic BAL in the diagnosis of ventilator-associated pneumonia.  Chest. 2000;  117 198S-202S