Introduction: Acute respiratory distress syndrome (ARDS) is a life-threatening condition marked by severe hypoxemia and poor lung compliance. Extracorporeal membrane oxygenation (ECMO) serves as a salvage therapy in refractory ARDS cases. While volume-outcome relationships are recognized in many clinical areas, their relevance in ECMO for ARDS remains unclear. We hypothesized that hospital ECMO volume would be associated with differences in patient outcomes. Methods: We performed a retrospective analysis of the 2018–2022 National Inpatient Sample (NIS), identifying adult hospitalizations with both ECMO and ARDS using ICD-10 codes. Hospitals were grouped into tertiles based on annual ECMO volume. Primary outcome was in-hospital mortality; secondary outcomes included acute kidney injury (AKI), disseminated intravascular coagulation (DIC), stroke, length of stay (LOS), and total charges. Survey-weighted analyses accounted for discharge weights, clustering, and stratification to generate national estimates. Baseline characteristics were compared using design-adjusted F-tests. Survey-weighted logistic and linear regression models adjusted for demographics and hospital characteristics. LOS and charge analyses were unweighted due to the absence of replicate weights. Results: We identified 2, 775 unweighted ECMO hospitalizations (weighted N = 13, 874, 997). Mortality was highest in medium-volume centers (48. 9%) versus low (40. 3%) and high (47. 6%). Median LOS and charges rose across tertiles: 23 days and 756, 971 in low-volume centers to 33 days and 1, 034, 503 in high-volume centers. Complication rates were broadly similar across tertiles. In adjusted models, both medium- and high-volume centers had higher mortality odds compared to low-volume (aOR 1. 36, p=0. 005 and aOR 1. 29, p=0. 023, respectively). LOS and hospital charges were significantly higher in medium- and high-volume tertiles (p< 0. 001 for both). No significant differences were found in complication rates. Conclusions: Contrary to common assumptions, high ECMO volume centers had higher mortality and resource use in ARDS patients. These findings suggest that factors beyond volume—such as institutional practices and care models—may influence ECMO outcomes and warrant further study.
Afzaal et al. (Sun,) studied this question.