Use of Extracorporeal Membrane Oxygenation in Obese COVID-19 Patients

Abstract

Rationale: Growing literature on the coronavirus disease 2019 (COVID-19) suggests that obesity (BMI > 30 kg/m2) is a strong risk factor for increasing disease severity, hospitalization and admission to the intensive care unit (ICU). In such critically ill patients with acute respiratory distress syndrome (ARDS), the use of extracorporeal membrane oxygenation (ECMO) can serve as salvage therapy. The Extracorporeal Life Support Organization (ELSO) COVID-19 ECMO registry reports that 49% of its patients were classified as obese as of 12/01/2020. However, the morbidity and mortality outcomes of this subgroup remains unclear. As such, this high-risk population merits further examination. Methods: We identified adult COVID-19 ARDS patients who were candidates for either veno-venous ECMO or veno-arterial ECMO between March 13, 2020 and August 31, 2020. The eligibility for ECMO was selected based on our institutional algorithm and the EOLIA Trial criteria (except for high BMI cutoff). Patients were divided into two groups, obese (BMI > 30 kg/m2) and non-obese (BMI < 29.9 kg/m2). We compared the pre-cannulation characteristics including time elapsed between admission to ECMO, intubation to ECMO and respiratory indices. We then examined length on ECMO, ICU or hospital length of stay and disposition. Fisher's exact and Mann-Whitney U tests were used to analyze categorical and continuous data. Results: We identified a total of 41 patients, 33 (80.5%) were obese and 8 (19.5%) were non-obese [Table 1]. The average age of the obese and non-obese groups was 47.8 years and 55.5 years respectively. The median BMI was 39.85 kg/m2 (IQR: 35.63, 43.00) in the obese group and 29.05 kg/m2 (IQR: 25.35, 29.39) in the non-obese group (p <0.00001). There was no difference in precannulation characteristics between the groups. In terms of timelines, the obese group was borderline significant with regards to more time elapsed between admission to ECMO (p = 0.058), however, no other significant changes were noted. The ICU length of stay was lower in the obese group with median runtime of 22 days versus 35.5 days (p = 0.029). There was no statistically significant difference in mortality (p = 0.43) or dispositions between the two groups. Conclusion: In our study, the obesity group did not have worse outcomes than the non-obese group. This should encourage consideration of ECMO in carefully selected obese patients with severe ARDS from COVID-19.