Outcomes of Obese Coronavirus 2019 Patients Treated with Extra Corporeal Membrane Oxygenation

Background: Veno-venous (VV) extracorporeal membrane oxygenation (ECMO) is used as salvage therapy in severe cases of acute respiratory distress syndrome (ARDS) caused by the coronavirus disease 2019 (COVID-19). Obesity has been linked to worse disease severity and poor outcomes in COVID-19, but there is also a hypothesized obesity survival paradox whereby obese patients fare better in severe illness than their non-obese complement. The effect of obesity on ECMO outcomes in patients with COVID-19 is not well understood. Methods: We performed a retrospective analysis of all patients admitted to our institution who underwent VV ECMO cannulation for COVID-19 in the span of one year. These were separated by body mass index (BMI) with a cutoff of 35 kg/m2 (signifying class 2 obesity or higher) and compared with each other as well as a comparator group of patients with BMI >35 kg/m2 who underwent VV ECMO cannulation for any cause between 2016 and 1 March 2021. Disease severity was categorized using established scoring systems including Apache- II, Charleson-Dayeo, and Murray. Primary endpoints were 30 day mortality, survival to decannulation, and survival to discharge. Results: The study groups were similar in all respects with the exception of BMI. Illness severity, as classified by Charleson-Dayeo, Apache II, and Murray scores not significantly different between groups. The primary outcomes (30-day mortality, survival to decannulation, and survival to discharge) were not significantly different between groups. There was a trend toward more delayed inititation of ECMO therapy in the obese group that was not statistically significant. There was also a trend toward shorter duration of ECMO therapy that did not reach the threshold for statistical significance. Conclusions: There was no significant difference in outcomes between obese and non-obese patients undergoing VV ECMO for COVID-19. Trends toward shorter duration of ECMO and shorter intensive care unit (ICU) and hospital length of stay could represent the "obesity survival paradox" that has been described. Given similar outcomes, obesity should not be a contraindication to ECMO therapy for COVID-19.