Utility of bronchoalveolar lavage in assessing pneumonia in immunosuppressed renal transplant recipients

Abstract

purpose: To determine if initial results obtained from diagnostic bronchoalveolar lavage (BAL) in immunosuppressed renal transplant patients with pulmonary infiltrates, fever, or hypoxemia can affect therapeutic decisions, morbidity, and mortality. design: A retrospective study of all BAL specimens obtained from renal transplant patients from January 1985 through June 1991. Initial results of Gram stain, cytology, cell differential count, and semi-quantitative bacterial cultures, all available within 24 hours of bronchoscopy, were compared with clinical outcomes and final diagnosis. setting: University hospital nephrology-transplant/pulmonary service. patients: Seventy renal transplant patients with a suspected pneumonia were stratified into 3 groups. A total of 48 patients underwent 58 bronchoscopies. Group 1 was comprised of 32 BALS that yielded 1 or more infectious organisms and was considered diagnostic. Group 2 (n = 26) were those BALs in which no organism was isolated and were thus nondiagnostic. Twenty-two additional immunosuppressed renal transplant recipients with pneumonia were considered by the admitting transplant nephrologist to have an uncomplicated community-acquired lung infection and thus were empirically treated and did not undergo BAL (Group 3). methods: BAL fluid analysis included cell differential count, cytopathologic examination, and culture for mycobacteria, legionella, fungi, viruses, and bacteria using a semi-quantitative technique. Etiologic diagnosis and the time of onset of the infectious processes were recorded. Therapeutic outcome and mortality were determined for each group. results: Thirty-nine etiologic organisms were found in 32 patients, with 6 patients having more than 1 infection. Twenty-two patients had 26 negative BALs, and 8 of these patients were clinically believed to have a volume overload state. Eight of 13 (61%) patients with bacterial pneumonia had BAL neutrophil counts greater than 20%, whereas 11 of 13 (84%) patients without bacterial pneumonia had neutrophil counts less than 20% (p <0.05). Those patients with an infectious etiology remained in the hospital longer than patients without a specific etiologic organism identified (p <0.02). Therapeutic decisions leading to the institution of specific antibiotics were more frequently made in patients with a diagnostic BAL (p <0.0001). An overall 3-month mortality (16%) was low compared with the historical rate (30%). conclusion: BAL is a useful procedure in the diagnosis of an infectious process in immunosuppressed renal transplant patients where initial results can alter therapy in more than 70% of cases.