Background: Extracorporeal membrane oxygenation (ECMO) candidacy decisions for children with respiratory failure can be variable among pediatric critical care attending physicians, and prior studies showed that baseline functional status and underlying neurological conditions influence this decision. However, there are limited data regarding factors influencing pediatric critical care fellows’ ECMO candidacy decisions and their alignment with attending physicians. This study aimed to identify patient characteristics influencing fellows’ ECMO candidacy decisions and measure concordance with attending decisions. 

Methods: This study was a planned secondary analysis of a prospective, single-center, cross-sectional study at a quaternary pediatric ECMO referral center. Pediatric critical care fellows and attending physicians caring for children admitted with acute respiratory failure were surveyed within 72 h of initiation or escalation of respiratory support. The primary exposure was patient functional status at admission, measured by the functional status score (FSS), and was categorized as Normal/Mild Dysfunction (FSS 6–9) or Moderate/Severe Dysfunction (FSS >10). Multivariate logistic regression clustered by fellow evaluated factors influencing ECMO candidacy assessments. Cohen’s kappa measured concordance between fellow and attending decisions. 

Results: Eighty surveys were completed by 21 pediatric critical care fellows. Fellows identified 19% of patients as ECMO non-candidates. After adjustment for age, moderate/severe admission dysfunction significantly reduced the odds of ECMO candidacy (aOR 0.11, 95% CI 0.03–0.51, p = 0.005). Overall, concordance between fellows and attendings was moderate (κ = 0.56), with junior fellows having minimal agreement (κ = −0.12). Fellows focused primarily on baseline functional status and comorbidities, while attendings considered additional factors, including long-term prognosis, organ failure irreversibility, and ECMO-related risks in candidacy assessments. 

Conclusion: Admission functional status influences pediatric critical care fellows’ ECMO candidacy decisions, with moderate concordance observed between fellows and attending physicians. The identified discrepancies emphasize the importance of structured education and targeted mentorship programs to enhance consistency in ECMO candidacy assessments, especially among junior trainees.