The expanding availability of venovenous extracorporeal membrane oxygenation (ECMO) and the increasing frequency of prolonged ECMO runs challenge standard definitions of center experience based solely on patient counts. We examined the relationship between center experience and patient outcomes using annual venovenous ECMO day volume (total days of venovenous ECMO support per center-year), a metric that integrates both procedural frequency and exposure to prolonged support and may better reflect institutional expertise.

Among adults supported with venovenous ECMO, is higher annual center venovenous ECMO day volume associated with lower in-hospital mortality and fewer ECMO-related complications, and does this relationship vary by average ECMO run duration?

We examined adult patients in the Extracorporeal Life Support Organization (ELSO) Registry supported with venovenous ECMO between 2014 and 2024. The associations among center experience, in-hospital mortality, and ECMO-related complications were examined using mixed-effect models adjusted for illness severity, calendar year, and clustering within centers.

Among 54,036 patients, center experience was associated independently with lower in-hospital mortality and fewer ECMO-related complications. Each doubling of annual venovenous ECMO days was associated with a 4% reduction in the odds of death (OR, 0.96; 95% CI, 0.93-0.98). The association was most pronounced among centers with longer average ECMO run duration (> 18 days; OR, 0.95; 95% CI, 0.91-0.99), whereas no significant volume-mortality association was observed in centers with shorter average run duration. In exploratory analysis, center learning was observed to increase quickly and plateau as ELSO reported experience was gained, an association that may allow for newly established centers to achieve expertise rapidly.

Our results show that higher venovenous ECMO day volume is associated with lower in-hospital mortality and fewer ECMO-related complications. This metric incorporates frequency and duration of support and may complement patient counts when describing center experience.