(193) Outcomes on Venovenous Conversion to Venoarterial or Hybrid ECMO in Adult Patients With COVID-19

Introduction: Acute respiratory distress syndrome (ARDS) is a common presentation of patients with COVID-19 that often requires the initial use of venovenous extracorporeal membrane oxygenation (VV-ECMO) for management, but its clinical course may necessitate conversion to alternative ECMO configurations as V-A (including VV-A), V-AV (including VV-AV), and V-PA. Our study aims to provide insights into the characteristics and outcomes associated with conversion.

Methods: We performed a retrospective analysis from the ELSO registry on all adult patients (≥ 18 years old) diagnosed with COVID-19 based on ICD-10 coding who received VV-ECMO between 2020 and 2022. Descriptive statistics were performed for categorical and continuous variables in our study population, comparing patients with COVID-19 supported by VV-ECMO who did or did not require conversion to a VA or hybrid ECMO configuration at the time of data query. We also performed a 3:1 propensity score matching to further examine the all-cause mortality associated with conversion.

Results: Out of 12,858 patients initially started on VV-ECMO, there was a 3% conversion rate to VA-ECMO or other hybrid configurations. There were no significant differences in baseline characteristics. Pre-ECMO arrest (5.1% vs 3.1%, p< 0.05) and renal replacement therapy (RRT) (45.6% vs 24.5%, p< 0.05) were more prevalent in the conversion group. The conversion group also had a higher in-hospital mortality (66.2% vs 48.7%, p< 0.05), and longer duration of ECMO support (1238 ± 63 hours vs 654 ± 5.9 hours, p< 0.05). After propensity matching, the conversion of VV-ECMO to an alternative mode is associated with a mortality rate of 22.7% (95% CI: 16.4 – 29.1, p< 0.001). There continues to be an increased incidence of CPR requirement, cardiac arrhythmias, pneumothorax, and gastrointestinal bleeding associated with the conversion group.

Conclusions: In conclusion, this study provides valuable insights into the clinical factors, outcomes, treatment modalities, and complication rates associated with VV-ECMO and its conversion to other ECMO configurations. Further research is warranted to better understand the underlying mechanisms and optimize treatment strategies in this complex patient population.