Predictors of survival in adult patients receiving VA-ECMO in the emergency setting: a systematic review

Background: Venoarterial extracorporeal membrane oxygenation is used in ER as support for adult patients with refractory cardiogenic shock and cardiac arrest. Survival differs because candidates age varieties, arrest profile, shock etiology, low-flow duration, metabolic injury, and early complications. This systematic review analyzed predictors of survival in adults receiving VA-ECMO or ECPR during emergency presentation. Methods: We conduct a systematic review according to PRISMA principles. PubMed, Scopus, Web of Science, and the Cochrane Library were searched for adult studies evaluating VA-ECMO or ECPR in ER (emergency department cannulation, refractory cardiac arrest, out-of-hospital cardiac arrest, in-hospital cardiac arrest, and acute cardiogenic shock requiring urgent circulatory support). We consider original studies reporting survival or neurological survival with clinical, biochemical, procedural, or scoring predictors. Results: Ten original studies were included in the final synthesis. The strongest predictors were younger age, witnessed arrest, shockable rhythm, shorter CPR or low-flow duration, lower lactate, higher pH or bicarbonate, preserved organ function, successful early revascularization in ischemic shock, and higher SAVE scores. Adverse predictors included older age, prolonged low-flow duration, asystole, severe acidosis, high lactate, renal injury, coagulopathy, major bleeding, vascular complications, and need for renal replacement therapy. Data in infarct-related cardiogenic shock found no survival advantage from routine early VA-ECMO in unselected patients. Conclusion: Survival after emergency VA-ECMO is determined by a cluster of pre-ECMO, intra-resuscitation, and early post-cannulation factors rather than a single variable. Candidate selection using age, arrest rhythm, low-flow time, lactate, pH, organ dysfunction, and validated scores offers a practical approach for emergency decision-making.