Optimal ECMO Flow in the Critical Phase of Cardiogenic Shock to Optimize Peripheral Organ Perfusion and Myocardial Stress

Veno-arterial ECMO (VA ECMO) is considered the ultimate lifesaving technique in refractory cardiogenic shock (CS). However, VA ECMO is associated with potentially serious adverse effects and complications. Many authors have demonstrated that VA ECMO increases left ventricular (LV) afterload, leading to increased LV stress, left ventricular end-diastolic pressure (LVEDP), and left atrial pressure (LAP). This pressure increase frequently results in pulmonary oedema and higher myocardial oxygen consumption. These complications are critical to patient survival and myocardial recovery and can lead to prolonged hospital stays and increased healthcare costs.

In the absence of clinical studies and strong recommendations, the optimized management of VA ECMO in clinical practice involves finding an ECMO flow that balances adequate organ perfusion with preserved ventricular ejection, while minimizing LV stress. Since the optimal flow changes with myocardial recovery, ramp tests are regularly performed to adjust ECMO flow.

To date, the optimized management of VA ECMO has been guided empirically. The aim of this study is to describe the consequences of variations in VA ECMO flow during the critical phase of cardiogenic shock on peripheral organ perfusion and LV stress. By analyzing the relationships between VA ECMO flow rate, peripheral perfusion, and myocardial stress, investigators aim to optimize flow settings-particularly by minimizing the potential complications of VA ECMO.

During the daily ramp tests, investigators plan to collect hemodynamic data (cardiac output, SvO₂, pulse pressure, EtCO₂, vasopressor and inotrope dosing), echocardiographic measurements, and organ perfusion indicators (NIRSS, CO₂ gap, respiratory quotient, lactate levels). Data will be collected on Day 1 (ECMO initiation), Day 2 (24 hours after ECMO initiation), and Day 3 (48 hours after ECMO initiation).