Pneumothorax in acute respiratory distress syndrome on extracorporeal membrane oxygenation support

Introduction Pneumothorax is associated with poor prognosis in patients with acute respiratory distress syndrome (ARDS). We sought to examine the outcomes of patients who are supported on veno-venous extracorporeal membrane oxygenation (VV ECMO) and develop a pneumothorax. Methods We retrospectively reviewed all adult VV ECMO patients supported for ARDS between 8/2014-7/2020 at our institution, excluding patients with recent lung resection and trauma. Clinical outcomes were compared between patients with a pneumothorax to those without a pneumothorax. Results Two hundred eighty patients with ARDS on VV ECMO were analyzed. Of those, 213 did not have a pneumothorax and 67 did. Patients with a pneumothorax had a longer duration of ECMO support (30 days [16-55] versus 12 [7-22], p < 0.001) and hospital length of stay (51 days [27-93] versus 29 [18-49], p < 0.001), and lower survival-to-discharge (58.2% versus 77.5%, p = 0.002) compared to patients without a pneumothorax. Controlling for age, BMI, sex, RESP score and pre-ECMO ventilator days, the odds ratio of survival-to-discharge was 0.41 (95% CI 0.22-0.78) in patients with a pneumothorax compared to those without. There was a lower incidence of significant bleeding when chest tubes were placed by proceduralist services (2.4% versus 16.2%, p = 0.03). Removal of the chest tube prior to ECMO decannulation compared to removal after decannulation was associated with need for replacement (14.3% versus 0%, p = 0.01). Conclusion Patients who develop a pneumothorax and are supported with VV ECMO for ARDS have longer duration on ECMO and decreased survival. Further studies are needed to assess risk factors for development of pneumothorax in this patient population.