Prospective studies with stringent criteria for determination of diagnostic yield for any pulmonary procedure are difficult to design. These studies would clearly identify whether histology, autopsy, other cultures, or clinical outcome confirmed the pulmonary isolate. There are many situations for which the latter choice is appropriate, but these merit a separate category when diagnostic yield is presented. This same category should also be used to limit reporting nonspecific fibrosis by TBBX or OLB as a specific diagnosis. This finding may carry the same implication as negative for pathogens, but it does not represent the impact of identification of a treatable pathogen or condition. zaditor eye drops
Some reports continue to present diagnostic yield by consolidation of many different subsets. Since differences in pathogen isolation between subsets and risk-benefit analysis for procedures among subsets is now well defined in the literature, it is surprising that this practice has not been abandoned. For example, including Pneumocystis carinii isolation by BAL or TBBX in patients with AIDS can falsely raise expectations for a true-positive isolate by these procedures in other subsets. Even in a patient with AIDS, BAL is seldom reliable as the sole diagnostic source when the clinician suspects pathogens or processes other than Pneumocystis carinii.
It has also been suggested that BAL may diagnose hemorrhage in the immunosuppressed host; however, bleeding accompanies many infectious agents and other processes. Hemorrhage can be safely assumed to be the sole cause for pulmonary infiltrates only when hemosiderin-laden macrophages predominate in the lavage, pulmonary edema has been excluded, therapy is not altered, and the alveolar disease clears rapidly (one to three days).
All of the pulmonary procedures are complementary and can be used in an additive fashion, since each is relatively safe at some point in the treatment course. Those patients without increased risk for bleeding should be approached aggressively for lung tissue (TBBX or TNA) for histology and culture. As research on the efficacy of lavage effluent analysis continues, some consistency between those effluents and lung parenchymal findings will need to be identified. With the accumulated experience reported in the immunocompromised host literature, enthusiasm for additive benefit from OLB has waned. We must exercise caution before re-directing such enthusiasm to the diagnostic power of BAL in that same literature.