Peripheral VA-ECMO most often uses the femoral vein and artery for cannulation. As a result, retrograde flow from the arterial cannula into the aorta can compete with the native antegrade flow through the heart. The native flow can often be deoxygenated blood, as lung function can be impaired by pulmonary edema, pneumonia, and so on. This results in differential systemic oxygenation (North/South syndrome), as the blood moving through native circulation through injured lungs has poor oxygenation while retrograde blood from the peripheral arterial cannula delivers oxygenated blood. Arterial blood gas should be checked from the right upper extremity artery to ensure proper cerebral oxygenation.

References

• ELSO Guidelines for Cardiopulmonary Extracorporeal Life Support Extracorporeal Life Support Organization, Version 1.4. Accessed May 14, 2023. www.elso.org
• Rao P, Khalpey Z, Smith R, Burkhoff D, Kociol RD. Venoarterial extracorporeal membrane oxygenation for cardiogenic shock and cardiac arrest. Circ Heart Fail. 2018;11:e004905.