Transbronchial cryobiopsy in unexplained, severe ARDS: a single center retrospective case series.

BACKGROUND: Acute respiratory distress syndrome (ARDS) deptics an acute form of lung infjury with often severe respiratory impairment that requires invasive mechanical ventilation. Since ARDS can be caused by several distinct etiologies, correct characterization is desired and frequently challenging. Surgical lung biopsy was previously reported to be of additive value. We describe our institutional experience using transbronchial cryobiopsy (TBCB) for further characterization of severe and unexplained ARDS cases.

CASE PRESENTATION: We retrospectively collected data of TBCB in patients with unexplained ARDS, whether with or without ECMO-support. Between 2019 and 2020 TBCB was performed in eight patients. Decision for the intervention was decided in multidisciplinary discussion. Five patients were treated with ECMO. The median duration of invasive ventilation before TBCB was 24 days. TBCB was performed in one segment, that was prophylactically occluded by Watanabe spigot or swab after the procedure. Histology results and their contribution to further therapeutic decisions were analyzed. Histology revealed five diffuses alveolar damage, one acute fibrinoid organizing pneumonia, one cryptogenic organizing pneumonia and one lung cancer. All results contributed to the decision of further management. While no pneumothorax or severe endobronchial bleeding occurred, two delayed hematothoraces needed surgical treatment. No patients died due to TBCB.

CONCLUSION: TBCB is feasible in ARDS even during ECMO treatment. Histologic results can play a significant role in therapeutic and ethic discussion to guide the patients' care. Side effects should be considered and monitored.