Introduction: Severe obesity has been considered a relative contraindication for ECMO initiation. Nevertheless, patients with moderate and severe obesity supported with VV ECMO have similar ICU LOS, successful weaning from ECMO, and similar or decreased mortality compared to patients with normal weight, overweight or mild obesity. Methods: Retrospective study in patients 10 to 40 years of age supported on VV ECMO for COVID-19 included in the ELSO Registry (January 2020 - July 2023). Determined exempt from human subjects review by the University of Michigan IRB (HUM00238700). Primary outcome of in-hospital mortality was evaluated by multivariate logistic regression models controlling for confounders and factors associated with increased mortality risk. Results: Of 3,631 patients with COVID-19 supported with VV ECMO, 29% were normal weight/ overweight, 43% had mild to moderate obesity, and 28% had severe obesity. Patients with severe obesity received BiPAP, neuromuscular blockade, and pulmonary vasodilators more frequently, but were proned less prior to ECMO. The risk-adjusted mortality was 33% in normal weight and overweight, 36% in those with mild to moderate obesity, and 38% in the severe obesity group (p=0.03). Severe obesity was independently associated with increased risk for mortality compared to normal weight and overweight in all patients OR 1.14; (95% CI 1.03 – 1.27), p=0.0146 and adolescents (10-18 years of age) OR 1.79; (95% CI 1.04 -3.06), p=0.0359, but not in young adults (19-40 years of age) OR 1.10; (95% CI 0.99 – 1.23), p=0.072. Normal weight or overweight, co-infections, pulmonary vasodilators and higher PaCO2 were associated with longer ECMO runs. Acute kidney injury and need for renal replacement therapy while on ECMO were more common in patients with severe obesity. Conclusions: Severe obesity had a modest but statistically significant association with mortality when compared to normal weight and overweight. While there is a difference in mortality among patients with obesity receiving ECMO, this difference is small and likely not clinically significant. Caution should be exercised before restricting ECMO support solely based on obesity status.
Suárez et al. (Sun,) studied this question.