ECMO Cannulation Techniques and Strategies 2

Question 1

During femoral veno-arterial ECMO cannulation, what is the primary concern when selecting the arterial cannula size?

Accepted Answer

Maximizing flow while minimizing distal limb ischemia risk

Answer

Femoral arterial cannula selection balances adequate ECMO flow with preservation of native limb perfusion to prevent distal ischemia.

Question 2

What is the purpose of a distal perfusion cannula (DPC) in femoral VA-ECMO?

Accepted Answer

To prevent ipsilateral lower limb ischemia

Answer

A DPC is placed in the superficial femoral artery to perfuse the limb distal to the ECMO arterial cannula, preventing ischemia.

Question 3

Which ultrasound view is most useful for confirming guidewire position in the inferior vena cava during femoral venous cannulation?

Accepted Answer

Subcostal or transesophageal bicaval view

Answer

The subcostal or TEE bicaval view provides direct visualization of the guidewire and cannula tip within the IVC and right atrium.

Question 4

In percutaneous cannulation, serial dilation of the vessel is performed to:

Accepted Answer

Gradually expand the access site to accommodate the final cannula

Answer

Sequential dilators progressively enlarge the puncture site so the large-bore ECMO cannula can be inserted without tearing the vessel.

Question 5

When transitioning from peripheral VA-ECMO to central cannulation, what is the main hemodynamic advantage?

Accepted Answer

Elimination of differential hypoxia by delivering oxygenated blood centrally

Answer

Central aortic return eliminates the mixing zone issue seen in peripheral VA-ECMO, preventing differential (Harlequin) hypoxia.

ECMO - Extracorporeal Membrane Oxygenation Practice Test