North-South syndrome

Q: What is North-south syndrome in peripheral Veno-arterial (VA) ECMO?

Answer: When patients are cannulated peripherally, i.e., the Femoral vein and Femoral artery, the upper part of the body may turn hypoxic. (see picture). This upper body hypoxia occurs when the heart ejects against the blood delivered retrogradely in the aorta through the femoral artery cannula. This creates a water shade area where the two blood streams meet in the middle. Blood delivered through an ECMO cannula is very oxygenated. Still, blood from the heart may not be well oxygenated, mainly when the lungs are not doing well and are flooded with pulmonary edema. This is called North-South or Harlequin syndrome, as a patient may have a Harlequin-like appearance.

A few measures which help to resolve this are 

• Optimize the vent and other maneuvers in the lung 

• Using Esmolol drip to decrease hyperdynamic of the left ventricle 

• Applying a splitting Y connector to the arterial arm of the ECMO and delivering good-oxygenated blood into the venous and pulmonary circulation. 

In other words, VA ECMO has now become VAV ECMO. 

#hemodynamic

References:

1. Lindholm JA. Cannulation for veno-venous extracorporeal membrane oxygenation. J Thorac Dis. 2018 Mar;10(Suppl 5):S606-S612. doi: 10.21037/jtd.2018.03.101. PMID: 29732177; PMCID: PMC5911563. 

2. Prashant Rao, Zain Khalpey, Richard Smith, Daniel Burkhoff and Robb D. Kociol Venoarterial Extracorporeal Membrane Oxygenation for Cardiogenic Shock and Cardiac Arrest Cardinal Considerations for Initiation and Management Originally published, 18 Sep 2018,  https://doi.org/10.1161/CIRCHEARTFAILURE.118.004905 Circulation: Heart Failure. 2018;11:e004905