**7. Proposed weaning protocol**

Assessing the readiness for VA-ECMO weaning involves withdrawal or reversal of the inciting injury, maintenance or recovery of extracardiac organ function, and lastly myocardial recovery. Prior to weaning attempts, hemodynamic stability and adequate tissue perfusion defined as a MAP ≥ 60–65 mmHg while on minimal pressor support, arterial pulsatility and lactate levels < 2 mmol/L should be achieved. VA-ECMO flow should be reduced by 0.5–1.0 L/min in 5–10-min intervals with continuous invasive hemodynamic and echocardiographic monitoring. In instances where adequate transthoracic windows cannot be achieved, transesophageal echocardiogram should be performed, and biventricular size and function monitored. Because some parameters of left ventricular function including aortic VTI and TDSa are not easily obtained by both transthoracic and transesophageal echocardiography, we recommend measuring changes in ventricular size and visual assessments of ventricular function and valvular regurgitation. In instances where CVP rises to greater than 1518 mmHg (depending on ventilator settings) and the RV dilates with worsening function and tricuspid regurgitation, the weaning trial should be aborted. Left sided function and loading conditions may vary depending on venting strategies, however, in cases where PCWP rises above 20 mmHg and

arterial line pulsatility is lost due to LV dysfunction, isolated LV mechanical support should be considered. Prior to final decannulation in the operating room, the VA-ECMO speed should be left at 1.5 L/minutes for an hour to assess stability of hemodynamic, echocardiographic and tissue perfusion parameters.
