Gastrointestinal complications in patients supported by venoarterial extracorporeal membrane oxygenation: Pathophysiological mechanisms and clinical implications.

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is a life-saving therapy for refractory shock; however, gastrointestinal (GI) complications have been reported in up to 50% of these patients and contribute substantially to morbidity and mortality. While early enteral nutrition (EN) improves outcomes in critical illness, enteral feeding intolerance (EFI) is common during VA-ECMO, and concerns regarding bowel ischemia frequently delay nutritional support. VA-ECMO introduces unique pathophysiological mechanisms - including non-pulsatile flow, retrograde aortic perfusion, and systemic inflammation - that alter gut perfusion and promote intestinal injury. This may create a complex interaction in which impaired intestinal barrier integrity facilitates bacterial translocation and potentially amplifies multiorgan dysfunction. Upper GI bleeding has been reported in approximately 10% of patients, driven by acquired coagulopathies and mandatory anticoagulation. Acute bowel ischemia affects 5%-9%, with mortality exceeding 75%, while EFI affects 33%-53%. Despite the clinical importance of these complications, current evidence remains fragmented, and the mechanisms underlying GI dysfunction during VA-ECMO have not been comprehensively synthesized. This narrative review summarizes the current evidence on the pathophysiological mechanisms, clinical manifestations, prognostic implications, and nutritional management of GI dysfunction in adult patients receiving VA-ECMO, highlighting current knowledge gaps and priorities for future research.