Extracorporeal membrane oxygenation for respiratory failure in phases of COVID-19 variants

Background: Adaptive mutations of the severe acute respiratory syndrome-related coronavirus (SARS-CoV-2) virus have emerged throughout the coronavirus disease 2019 (COVID-19) pandemic. The characterization of outcomes in patients requiring extracorporeal membrane oxygenation (ECMO) for severe respiratory distress from COVID-19 during the peak prevalence of different variants is not well known. Methods: There were 131 patients with laboratory-confirmed SARS-CoV-2 infection supported by ECMO at two referral centers within a large healthcare system. Three predominant variant phase time windows (Pre-Alpha, Alpha, and Delta) were determined by a change-point analyzer based on random population sampling and viral genome sequencing. Patient demographics and outcomes were compared. Results: The average age of patients was 46.9 ± 10.5 years and 70.2% (92/131) were male. Patients cannulated for ECMO during the Delta variant wave were younger compared to earlier Pre-Alpha (39.3 ± 7.8 vs. 48.0 ± 11.1 years) and Alpha phases (39.3 ± 7.8 vs. 47.2 ± 7.7 years) (p <.01). The predominantly affected race in the Pre-Alpha phase was Hispanic (52.2%; 47/90), while in Alpha (61.5%; 16/26) and Delta (40%; 6/15) variant waves, most patients were White (p <.01). Most patients received a tracheostomy (82.4%; 108/131) with a trend toward early intervention in later phases compared to Pre-Alpha (p <.01). There was no significant difference between the duration of ECMO, mechanical support, intensive care unit (ICU) length of stay (LOS), or hospital LOS over the three variant phases. The in-hospital mortality was overall 41.5% (54/131) and was also similar. Six-month survival of patients who survived to discharge was 92.2% (71/77). Conclusions: There was no significant difference in survival or time on ECMO support in patients during the peak prevalence of the three variants.