**Introduction/Hypothesis**
Extracorporeal membrane oxygenation (ECMO) has been utilized as a rescue therapy for patients with severe ARDS. Multiple case series have suggested that the duration of veno-venous ECMO support in patients with COVID-19 pneumonia may be longer than patients with ARDS secondary to alternative etiology. However, the impact of longer run of ECMO on patient outcomes is not clear

**Methods (e.g. case series, trial or case report)**
This was a retrospective study performed at Mayo Clinic Florida and Mayo Clinic Rochester, tertiary ECMO centers in USA. Analysis includes all consecutive patients who were placed on VV ECMO for COVID-19-induced ARDS between January 2019 to March 2022. The study population was classified into two groups: short term ECMO duration (< 4 weeks) and prolonged ECMO support (>4 weeks). We collected data on demographic and clinical characteristics, treatments administered, mechanical ventilator and ECMO parameters.

**Results**
A total of 66 COVID-19 patients were included. 65% of the study population were male and median age of the study group was 52 years. For the entire cohort, the 60- day mortality was 18%, with 4% mortality in short term ECMO group and 30.5% in prolonged ECMO group (p=0.008). The median duration of ECMO support was 34 days (IQR 15.5-57). The most common co-morbidities were prior cardiac disease (39%), obesity (39%), diabetes mellitus (21%) and prior respiratory disease (11%) but there were no significant differences between the two groups. Also, the rate of complications between two groups were similar.The median duration of mechanical ventilation between two group was 13.5 days vs 50.5 (p<0.001), median duration of hospital admission 31 days vs 63.5 days (p<0.001), median duration of ICU admission 22 days vs 57.5 days (p<0.001). The percentage of death in ICU was 14% in short term ECMO group and 60.7% in prolonged ECMO group (p=0.008), percentage of death in ECMO was 14% in short term ECMO group and 57% in prolonged ECMO group (p=0.01)

**Conclusion**
The study demonstrated that a substantial number of COVID19 patients require ECMO for > 4 weeks. In this cohort, the 60 days mortality rate  in ECMO support less than four weeks  was low, at 4%. The patients who required ECMO for >4 weeks were more likely to have higher mortality compared to the patients treated with ECMO for shorter duration.



Extracorporeal membrane oxygenation in patients with COVID-19: duration and outcomes