Cannulation Techniques and Strategies Flashcards

In venoarterial ECMO, retrograde flow through the femoral artery can cause what phenomenon in patients with recovering cardiac function?

Answer: Differential hypoxia (Harlequin syndrome)

When the recovering heart ejects deoxygenated blood that meets retrograde ECMO flow in the aorta, the upper body may receive hypoxic blood — Harlequin syndrome.

What does 'mal-position' of a venous drainage cannula into the hepatic vein most commonly cause?

Answer: Decreased venous drainage and 'chattering'

Hepatic vein malposition limits drainage volume, causing circuit chattering and inadequate ECMO support.

For a patient with bilateral femoral vessel pathology needing VA-ECMO, which alternative arterial site is most commonly used?

Answer: Axillary or subclavian artery

The axillary or subclavian artery is the preferred alternative arterial access when femoral vessels are unusable, allowing antegrade cerebral and upper body perfusion.

What is the rationale for placing a 'bridge' or purse-string suture around the arterial cannula insertion site during surgical cannulation?

Answer: To maintain cannula position and provide hemostasis upon decannulation

Purse-string sutures secure the cannula, prevent bleeding around it, and facilitate clean hemostasis when the cannula is removed.

When using TEE to guide ECMO cannulation, what finding confirms the guidewire is in the correct venous structure rather than the aorta?

Answer: Guidewire seen in the right atrium or IVC, not the descending aorta

TEE visualizing the guidewire within the right atrium or IVC confirms venous placement and rules out inadvertent aortic cannulation.

In pediatric VA-ECMO, central cannulation via the right atrium and aorta is often preferred over peripheral cannulation because:

Answer: Central cannulation avoids limb ischemia and allows higher flows in small patients

Small peripheral vessels in children limit flow and increase ischemia risk, making direct central cannulation safer and more effective.

Which of the following best describes the 'Y-connector' configuration used in some ECMO venous drainage setups?

Answer: Two drainage cannulas (femoral + jugular) joined to a single drainage limb to increase flow

A Y-connector combines drainage from both femoral and jugular veins into a single line, increasing total venous return when one cannula is insufficient.