Free ECMO Anticoagulation & Hemodynamics in ECMO Questions and Answers — Questions and Answers

Question 1: What is the primary purpose of anticoagulation during ECMO therapy?

To increase oxygen delivery
To prevent infection
To stop clot formation (Correct answer)
To reduce heart rate

Correct answer: To stop clot formation

The foreign surfaces of the ECMO circuit activate the coagulation cascade, making clot formation (thrombosis) a significant risk. Anticoagulation, typically with heparin, is administered to prevent these clots from forming within the circuit, which could lead to circuit failure, or from embolizing to the patient, causing severe complications like stroke or organ damage. This is crucial for circuit patency and patient safety.

Question 2: Which lab test is most commonly used to monitor heparin therapy in ECMO?

INR
aPTT (Correct answer)
Lactate
Creatinine

Correct answer: aPTT

The activated Partial Thromboplastin Time (aPTT) is a common laboratory test used to monitor the effectiveness of unfractionated heparin therapy, which is frequently used for anticoagulation during ECMO. It measures the time it takes for blood to clot via the intrinsic and common pathways, providing an indication of the patient's anticoagulation status and guiding heparin dosing.

Question 3: Which hemodynamic parameter indicates the afterload the heart must overcome?

Cardiac output
Central venous pressure
SVR (Correct answer)
Mean arterial pressure

Correct answer: SVR

Systemic Vascular Resistance (SVR) represents the total resistance to blood flow in the systemic circulation, which the left ventricle must overcome to eject blood. It is a key determinant of afterload, the pressure the heart works against. Monitoring SVR helps assess the patient's hemodynamic status and guides the use of vasoactive medications to optimize blood pressure and organ perfusion.

Question 4: What is the target ACT range for most ECMO protocols using heparin?

80–100 seconds
180–220 seconds (Correct answer)
250–300 seconds
350–400 seconds

Correct answer: 180–220 seconds

The target Activated Clotting Time (ACT) range for most ECMO protocols using unfractionated heparin is typically between 180 and 220 seconds. This range aims to provide adequate anticoagulation to prevent circuit thrombosis while minimizing the risk of bleeding complications. Specific targets can vary slightly based on institutional protocols, patient factors, and the type of ECMO support.

Question 5: Which complication can result from excessive anticoagulation during ECMO?

Stroke
Bleeding (Correct answer)
Hypertension
Bradycardia

Correct answer: Bleeding

While anticoagulation is essential to prevent clots in the ECMO circuit, excessive anticoagulation significantly increases the risk of bleeding. ECMO patients are already vulnerable to bleeding due to their critical illness, invasive procedures, and platelet dysfunction. Over-anticoagulation can lead to severe hemorrhage, which is a major cause of morbidity and mortality and requires careful management.

Question 6: Why is maintaining optimal hemodynamics important in ECMO patients?

To control oxygen saturation
To minimize sedative use
To support end-organ perfusion (Correct answer)
To stabilize glucose levels

Correct answer: To support end-organ perfusion

Maintaining optimal hemodynamics, including adequate blood pressure and cardiac output, is crucial for ensuring sufficient blood flow and oxygen delivery to all vital organs (end-organ perfusion). ECMO supports the heart and lungs, but stable hemodynamics are essential to prevent organ dysfunction and injury, which can lead to multi-organ failure and worsen patient outcomes.

Question 7: Which condition is associated with low hemoglobin and persistent bleeding in ECMO?

Thrombosis
Hemorrhage (Correct answer)
Sepsis
Volume overload

Correct answer: Hemorrhage

Hemorrhage refers to excessive bleeding, which directly leads to a decrease in circulating blood volume and red blood cells, thus causing low hemoglobin levels. In ECMO patients, persistent bleeding is a common and serious complication, often exacerbated by continuous anticoagulation and the patient's underlying critical illness. It requires prompt identification and management to prevent further blood loss and maintain oxygen-carrying capacity.

Question 8: What action should be taken if signs of heparin-induced thrombocytopenia (HIT) appear?

Increase heparin dose
Stop heparin and switch to alternative anticoagulant (Correct answer)
Flush the circuit
Reduce ECMO flow

Correct answer: Stop heparin and switch to alternative anticoagulant

Heparin-induced thrombocytopenia (HIT) is a severe, immune-mediated complication where heparin causes paradoxical thrombosis despite low platelet counts. Continuing heparin would worsen the condition and increase the risk of life-threatening blood clots. Therefore, immediate cessation of heparin and switching to an alternative anticoagulant is crucial to prevent further complications and manage this critical condition effectively.

Question 9: What is a typical sign of impaired venous return affecting hemodynamics?

Low CVP
Tachypnea
Jugular vein distension (Correct answer)
Hypothermia

Correct answer: Jugular vein distension

Impaired venous return means blood is not effectively flowing back to the heart, causing it to back up in the venous system. Jugular vein distension (JVD) is a classic clinical sign of increased central venous pressure, which directly indicates this backup of blood. This accumulation in the superior vena cava and its tributaries is a clear indicator of compromised venous return affecting hemodynamics.

Free ECMO Anticoagulation & Hemodynamics in ECMO Questions and Answers

What is the primary purpose of anticoagulation during ECMO therapy?