Sensitivity and specificity of bronchoalveolar lavage and protected bronchial brush in the diagnosis of pneumonia in pediatric burn patients

Background: Infection is still one of the leading causes of death in burn p atients. The diagnosis of respiratory tract infection in critically ill bur n patients is still difficult. The diagnostic technique of choice remains u ncertain, especially because of the lack of a criterion standard by which o ther diagnostic methods can be compared. Hypothesis: Bronchoalveolar lavage (BAL) and protected bronchial brush (PBB ) cultures are not efficacious for the diagnosis of pneumonia in critically ill burn patients. Design: All pediatric patients with burns who died at Shriners Burns Hospit al, Galveston, Tex, in the past 10 years were studied. We compared the clin ical diagnosis of pneumonia, BAL quantitative culture results, and PBB cult ure results with autopsy findings. The diagnosis of pneumonia at autopsy wa s considered the criterion standard, and it was used to calculate the sensi tivity and specificity of BAL and PBB cultures. Results: Forty-three patients were studied. Pneumonia was present in 19 (44 %) of the 43 autopsies. Pneumonia was diagnosed clinically in 12 (28%) of t he 43 patients, and 6 (50%) of them had negative autopsy findings. The sens itivity and specificity of BAL were 56% and 28%, respectively; PBB, 55% and 61%, respectively. The same microorganisms were found at autopsy, in BAL c ultures, and in PBB cultures in fewer than 10% of the patients. Conclusions: Bronchoalveolar lavage and protected bronchial brush have a lo w sensitivity and specificity and cannot be relied on by themselves for the diagnosis of pneumonia in critically ill burn patients. The results of the se sampling techniques must be interpreted in the context of the overall cl inical picture of each individual patient.