In extracorporeal life support and perfusion, progress has rarely followed the neat, linear hierarchy of evidence promoted by traditional evidence-based medicine. The randomized controlled trial (RCT) remains the proclaimed ‘gold standard’, yet its luster dims when applied to complex, technology-driven, patient-specific care environments such as cardiopulmonary bypass, extracorporeal membrane oxygenation (ECMO), and mechanical circulatory support. In these domains, the pursuit of large multicenter RCTs often collides with practical, ethical, and scientific limitations: small patient cohorts, heterogeneity in clinical settings, rapidly evolving devices, and profound interpatient variability and multifaceted complexity.

At the same time, the pages of Perfusion, this issue included, demonstrate a vibrant and empirically rich alternative: practice-based evidence emerging directly from the bedside. Each manuscript represents a piece of what could be considered an evolving mosaic of grounded clinical wisdom, being rigorous in observation, transparent in limitation, and deeply contextualized within the lived realities of perfusion practice.