Comparison of Extracorporeal Membrane Oxygenation Survivors with Non-Survivors; A Retrospective Analysis at a Quaternary Center

Rationale: International organizations, including the World Health Organization and Extracorporeal Life Support Organization have recommended the use of extracorporeal membrane oxygenation (ECMO) in the management of patients with Coronavirus Disease-19 (COVID-19) related acute respiratory distress syndrome (ARDS) based on favorable outcomes shown by some studies from earlier parts of the pandemic. Mortality rates of COVID-19 patients with the use of ECMO has ranged from 40-94%. Some reports suggest early initiation of ECMO leads to better outcomes before refractory hypoxemia leads to multi-organ failure. However, the predictors of mortality among COVID-19 patients treated with ECMO remain unclear. Also, ECMO has been associated with potentially life-threatening bleeding and thromboembolic complications. This study aims to identify the risk factors associated with the mortality in COVID-19 patients managed with ECMO and to assess the effect of ECMO related complications on mortality. Methods: Retrospective analysis of adult patients with COVID-related ARDS treated with ECMO at the ICUs of a quaternary care hospital between 03/01/2020 and 08/31/2021. Demographics, clinical characteristics, and outcomes of the patients who survived were compared with those who did not survive. Hemorrhagic complications were defined as bleeding requiring transfusion, hemorrhagic stroke and coagulopathy with International Normalized Ratio (INR) > 3. Thrombotic complications were defined as limb ischemia and ischemic stroke. Myocardial dysfunction was defined as a drop in ejection fraction to less than 30%, liver dysfunction as alanine transaminase (ALT) greater than 5 times of upper normal limit (ULN), and kidney involvement as acute kidney injury (AKI) requiring dialysis. Results: Of the 31 COVID-19 patients managed with ECMO during the study period, 11 (36%) patients survived. Both groups were similar in terms of age, gender, comorbidity burden (measured by Charlson Comorbidity Index), and severity of illness at the time of ICU admission (assessed by APACHE-IV score). Days spent on mechanical ventilation (MV) before ECMO cannulation were lower in survivors as compared to non-survivors but the difference was not statistically different. The incidence of complications was not statistically different between two groups. Conclusion: Our study shows a survival rate in COVID-19 patients treated with ECMO that is similar to previously reported studies. Our study did not reveal any significant predictive differences between survivors and nonsurvivors, thereby continuing to make the process of patient selection for ECMO challenging during this pandemic. Our study is limited by a relatively small sample size and therefore larger studies will be needed to confirm our findings.