A Comparison of Outcomes for Patients with ARDS Secondary to COVID-19 Infection and Viral Pneumonia Treated with Extracorporeal Membrane Oxygenation

Abstract

RationaleThe role of venous-venous extracorporeal membrane oxygenation (ECMO) in the management of acute respiratory distress syndrome (ARDS) due to COVID-19 infection remains uncertain. This observational study aimed to compare the outcomes of a cohort of COVID-19 patients and a cohort of patients with viral ARDS of different aetiology commenced on ECMO at a single tertiary centre. MethodsAll COVID-19 positive patients admitted to the Royal Brompton Hospital, one of five ECMO referral centres in the UK, between 17th March and 30th May 2020 for ECMO treatment were identified for inclusion (N=52). A cohort of consecutive patients admitted for ECMO support with a primary diagnosis of viral ARDS during the two years preceding the coronavirus pandemic were identified for comparison (N=53). Baseline patient characteristics, patient outcomes, complications and ECMO parameters were collated and analysed. This study was registered with the Integrated Research Application System (Project ID: 285452) and ethical approval was granted by the Research Ethics Council (reference 20/EM/0204). ResultsNo significant difference was found in 30-day mortality (11.5 vs. 11.3%, P=0.972), 60-day mortality (15.4 vs. 22.6%, P=0.347), the proportion of patients who survived to ECMO decannulation (90.4 vs. 83.0%, P=0.267) and the proportion of patients who survived to discharge from ICU (83.1 vs. 71.7%, P=0.148). Similarly, the incidence of peri-ECMO complications were comparable between the two cohorts except for pulmonary embolus which was markedly more common in the COVID-19 cohort (57.7 vs. 24.5%, P=<0.001). A longer average length of ECMO run (22.5 vs. 15.3 days, P=0.015) and stay in ICU (40.2 vs. 33.4 days, P=0.089) was observed in the COVID-19 cohort although this difference was not statistically significant. Increased ECMO dependence, as measured by sweep gas and circuit flow rates required to maintain adequate gas exchange, was observed in the COVID-19 cohort. ConclusionsThese results demonstrate comparable short-term outcomes for patients with COVID-19 and viral ARDS due to other causes treated with venous-venous ECMO. Increased ECMO dependence and length of ECMO run in this series are likely to reflect a trend towards accepting patients with more severe isolated respiratory failure during the COVID-19 pandemic. This data supports the equitable use of ECMO for advanced respiratory support for viral pneumonia of any cause.