CVP ECMO and Mechanical Circulatory Support Flashcards

What is 'Harlequin syndrome' (North-South syndrome) in VA-ECMO?

Answer: Differential oxygenation between upper and lower body due to competing native cardiac output and ECMO return

Harlequin syndrome occurs when the recovering native heart ejects poorly oxygenated blood to the upper body while ECMO returns well-oxygenated blood to the lower body via the femoral artery.

What is the primary function of the oxygenator membrane in an ECMO circuit?

Answer: To remove CO2 from and add O2 to blood across a hollow-fiber membrane

The hollow-fiber membrane oxygenator allows gas exchange across a semi-permeable membrane: O2 diffuses in and CO2 diffuses out driven by concentration gradients.

What serious vascular complication is associated with femoral arterial VA-ECMO cannulation?

Answer: Limb ischemia distal to the arterial cannula

The large arterial cannula can obstruct femoral artery flow, causing acute limb ischemia distal to the insertion site, requiring vigilant monitoring and often a distal perfusion cannula.

How is ECMO flow rate primarily managed by the perfusionist?

Answer: By adjusting pump speed (RPM) while monitoring flow, pressures, and patient hemodynamics

The perfusionist titrates pump RPM to achieve target flow (typically 60–80 mL/kg/min for VA-ECMO) while monitoring circuit pressures, arterial saturation, and clinical perfusion markers.

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

Answer: To perfuse the limb distal to the arterial cannula and prevent ischemia

A DPC is a small-diameter side cannula placed distal to the main arterial cannula, connected to the ECMO circuit to maintain limb perfusion and prevent ischemic complications.

ECMO support is generally considered contraindicated in which of the following situations?

Answer: Irreversible organ failure with no candidacy for transplant or recovery

ECMO is a bridge — to recovery, to decision, or to transplant — and is not appropriate when there is no realistic chance of meaningful recovery or transplant eligibility.