Veno-Arterial Extracorporeal Membrane Oxygenation (VA-ECMO)

The ultimate resuscitative therapy for catastrophic biventricular failure or cardiac arrest (ECPR). VA-ECMO drains deoxygenated venous blood from the right atrium, routes it through an external membrane oxygenator, and pumps it continuously into the arterial circulation (typically the femoral artery) under high pressure. While it provides massive total-body circulatory and respiratory support, its physiological mechanism introduces a severe paradox: by pumping blood retrogradely up the descending aorta, VA-ECMO massively increases left ventricular afterload. If the failing left ventricle is too weak to eject against this increased afterload, it can lead to progressive LV distension, elevated left atrial and pulmonary capillary pressures, and pulmonary edema -- often requiring a concomitant LV venting or unloading strategy (e.g., Impella, IABP, or atrial septostomy) to mitigate this effect.