Extracorporeal membrane oxygenation for COVID-19 during first and second waves
Abstract
COVID-19 has ravished the world, with secondary consequences that are not yet possible to estimate. WHO and the European Extracorporeal Life Support Organization (ELSO) recommended extracorporeal membrane oxygenation (ECMO) early in the pandemic, according to the standard criteria. In March, 2020, the EuroELSO survey was established to report the use of ECMO and outcomes in patients with COVID-19 once per week.1
Several months into the pandemic, we learned empirically that steroids and thromboprophylaxis improved outcome, which was confirmed by subsequent studies.2, 3, 4 Data from the EuroECMO survey collected between March 12, 2020, and Sept 14, 2020 (ie, the first wave), and other multicentre aggregates showed favourable outcomes with survival of 55–60%.1, 5 Less encouraging outcomes were also reported, with survival rate of less than 30%.6
We analysed the continuous provision of ECMO for patients with COVID-19 during the first and second waves from the EuroECMO survey. Our results indicate that the clinical picture has changed during the second wave (between Sept 15, 2020, and March 8, 2021). Fatality and successful weaning curves approach each other, indicating an increase in mortality compared with weaning and survival (figure 1). An analysis of the deceased to weaned ratio during 2020 shows a significantly increasing trend over time (figure 2). During the spring and early summer of 2020, this ratio was less than 1—ie, the number of weaned (survivors from ECMO) was higher than the number of deceased. Currently, this ratio is more than 1, indicating worse outcome (p<0·006; median–median linear regression). The same pattern emerges concerning survival between first and second waves on the basis of data released on March 8, 2021. In the first wave, successful weaning was accomplished in 58% (841 of 1442) of patients, compared with 47% (718 of 1723; p<0·0001) in the second wave. Including deaths reported after successful weaning, survival was 53% (770) in the first wave and 44% (677; p<0.0001) in the second wave.