OPEN-LUNG BIOPSY IN PATIENTS WITH ACUTE RESPIRATORY-DISTRESS SYNDROME

Background: It has been suggested that fibrosis present during the fib roproliferative phase of acute respiratory distress syndrome (ARDS) ca n be treated by corticosteroids. However, neither clinical nor microbi ologic criteria permit differentiation of this fibroproliferative phas e from a nosocomial pneumonia The aim of this observational case serie s was to evaluate the safety and utility of open-lung biopsy (OLB) per formed in patients receiving ventilatory support who had persistent AR DS despite negative bacterial cultures. Methods: During a 4-yr period, 37 OLBs were performed in 36 of 197 patients receiving ventilatory su pport who had ARDS. The severity of ARDS was assessed by a lung injury score of 3.1 +/- 0.4 (mean +/- SD) and a median ratio of the partial pressure of oxygen (Pa-O2) to the fraction of inspired oxygen (FIO2) o f 118 mmHg. Histologic examination; bacterial, fungal, and acid-fast s taining; and cultures of the tissue sample were performed. Results: Fi brosis was present in only 41% of the lung specimens obtained by OLB. Only six patients received corticosteroids (17%). In 9 of the 15 patie nts with fibrosis, cytomegalovirus pneumonia precluded the use of cort icosteroids. Histologic cytomegalovirus pneumonia was diagnosed in 18 cases. Histologic bacterial or mycobacterial pneumonia was diagnosed i n five cases. No significant change in arterial blood gases was noted as linked to the biopsy procedure except an increase of the Pa-O2/FiO( 2) ratio. One pneumothorax was diagnosed on a chest roentgenogram 12 h after OLB. Only one patient required blood transfusion during the 48- h period after OLB (for an hemothorax). Five patients had moderate air leaks from operative chest tubes for 2-10 days. Conclusions: Open lun g biopsy appeared to be a useful and acceptably safe diagnostic techni que in patients with ARDS. It permitted the diagnosis of unexpected cy tomegalovirus pneumonia.