Diagnosis and outcome of early pleural space infection following lung transplantation

Background: Despite the frequent occurrence of pleural effusions in lung transplant recipients, little is known about early posttransplant pleural space infections. We sought to determine the predictors and clinical significance of pleural infection in this population. Methods: We analyzed 455 consecutive lung transplant recipients and identified patients who had undergone sampling of pleural fluid within 90 days posttransplant. A case-control analysis was performed to determine the characteristics that predict infection and the impact of infection on posttransplant survival. Results: Pleural effusions undergoing drainage occurred in 27% of recipients (124 of 455 recipients). Ninety-six percent of effusions were exudative. Pleural space infection occurred in 27% of patients (34 of 124 patients) with effusions. The incidence of infection did not differ significantly by native lung disease or type of transplant operation. Fungal pathogens accounted for > 60% of the infections; Candida albicans was the predominant organism found. Bacterial etiologies were present in 25% of cases. Infected pleural effusions had elevated lactate dehydrogenase levels (p = 0.036) and markedly increased neutrophil levels in the pleural space (p < 0.0001) compared to noninfected effusions. A pleural neutrophil percentage of > 21% provides a sensitivity of 70% and a specificity of 79% for correctly identifying an infection. Patients with pleural space infection had a diminished 1-year survival rate compared to those without infection (67% vs 87%, respectively; p = 0.002). Conclusion: Pleural infection with fungal or bacterial pathogens commonly complicates lung transplantation, and an elevated neutrophil level in the pleural fluid is the most sensitive and specific indicator of infection.