ECMO Circuit Components and Management 4

Question 1

What is the primary hemodynamic difference between VA-ECMO and VV-ECMO?

Accepted Answer

VA-ECMO provides both cardiac and respiratory support while VV-ECMO provides respiratory support only

Answer

VA-ECMO bypasses both the heart and lungs providing cardiorespiratory support, whereas VV-ECMO only supports gas exchange with no direct cardiac output augmentation.

Question 2

The centrifugal pump used in modern ECMO circuits generates flow by:

Accepted Answer

Magnetically levitated or bearing-mounted impeller creating a pressure gradient via centrifugal force

Answer

Centrifugal pumps use a spinning impeller (constrained or magnetically levitated) to impart kinetic energy to blood, generating flow through centrifugal force.

Question 3

When performing an emergency hand-crank during a centrifugal pump power failure, the specialist should:

Accepted Answer

Maintain a minimum of 1.5–2 L/min flow to prevent circuit thrombosis and clamp lines if unable to hand-crank

Answer

During pump failure, maintaining minimal flow via hand-crank prevents stasis thrombosis; if hand-cranking is not feasible, clamping both limbs prevents backflow and air entrainment.

Question 4

The purpose of the heat exchanger integrated into the ECMO oxygenator is to:

Accepted Answer

Maintain normothermia or induce therapeutic hypothermia by warming or cooling circulating blood

Answer

The heat exchanger circulates water at a controlled temperature around the blood path, enabling precise temperature management including therapeutic cooling.

Question 5

Flow monitoring via ultrasonic flow probes on the ECMO circuit measures flow based on:

Accepted Answer

Transit-time ultrasound detecting changes in sound wave travel time caused by moving blood

Answer

Transit-time ultrasound flow probes measure the time difference between upstream and downstream ultrasonic pulses, which correlates directly to volumetric blood flow.

ECMO - Extracorporeal Membrane Oxygenation Practice Test

ECMO - Extracorporeal Membrane Oxygenation Practice Test

ECMO Circuit Components and Management 4