ECMO - Extracorporeal Membrane Oxygenation ECPR and Special Populations Questions and Answers

Question 1

A 58-year-old patient experiences a witnessed in-hospital cardiac arrest (IHCA) with an initial shockable rhythm. After 20 minutes of high-quality CPR and adherence to ACLS protocols, ROSC has not been achieved. Which of the following is the strongest indicator for transitioning to ECPR in this patient?

Accepted Answer

The patient's end-tidal CO2 (ETCO2) has remained consistently above 15 mmHg.

Answer

A sustained ETCO2 above 10-15 mmHg during CPR indicates effective chest compressions are generating some degree of pulmonary blood flow and metabolic activity, which is a favorable prognostic sign for ECPR. It suggests a potentially salvageable state, making the patient a better candidate. The other options are either less specific indicators (history of CAD), negative factors (unwitnessed arrest is less favorable), or simply process measures (epinephrine doses).

Question 2

Which of the following represents a unique and immediate challenge when establishing peripheral VA ECMO during active CPR (ECPR)?

Accepted Answer

Difficulty in identifying and cannulating collapsed femoral vessels.

Answer

During cardiac arrest, the absence of pulsatile arterial flow and the collapse of the venous system make vessel identification and cannulation extremely challenging, even with ultrasound guidance. This is a primary procedural hurdle that distinguishes ECPR from elective ECMO initiation and requires a highly skilled team to perform rapidly. Anticoagulation, hypothermia, and LV distention are all important considerations, but they are typically managed after vascular access is secured and ECMO flow has been initiated.

Question 3

When considering VA ECMO for a peripartum patient with refractory cardiogenic shock, which cannulation strategy is generally preferred to ensure adequate systemic and uterine perfusion?

Accepted Answer

Femoral vein drainage and axillary artery return, to perfuse the upper body and coronaries.

Answer

A femoral vein to axillary artery cannulation strategy provides anterograde flow of oxygenated blood to the aortic arch. This ensures perfusion of the coronary arteries and cerebral circulation, which is critical for maternal stability and avoids the differential hypoxia (Harlequin syndrome) associated with femoral-femoral VA ECMO, which could compromise both the mother and the fetus.

Question 4

A 30-year-old patient is placed on VA ECMO for refractory septic cardiomyopathy. Despite achieving target ECMO flows and mean arterial pressure, the patient's lactate remains elevated, and peripheral perfusion is poor. In this scenario of severe vasodilation due to sepsis, which adjunctive management strategy is most critical to improve end-organ perfusion?

Accepted Answer

Titrating vasopressor therapy to achieve an adequate mean arterial pressure.

Answer

In refractory septic shock, the underlying pathophysiology is profound vasodilation. While VA ECMO provides circulatory flow, it cannot restore vascular tone. Therefore, concurrent vasopressor therapy is essential to increase systemic vascular resistance (SVR) and achieve a mean arterial pressure (MAP) sufficient for end-organ perfusion. Without adequate MAP, the flow generated by the ECMO pump will not translate to effective tissue oxygen delivery.

Question 5

A 28-year-old patient with blunt chest trauma develops severe ARDS and requires VV ECMO. The patient has multiple rib fractures and a small, stable pulmonary contusion. The trauma team is concerned about bleeding risk. What is the most appropriate initial anticoagulation strategy for this patient?

Accepted Answer

Withhold systemic anticoagulation for the first 24-48 hours while monitoring for bleeding.

Answer

In trauma patients on ECMO, the risk of life-threatening hemorrhage often outweighs the risk of circuit thrombosis, especially in the early phase. A common approach is to withhold systemic anticoagulation for at least 24-48 hours, or until the sources of bleeding are controlled and the patient is stable. Modern heparin-bonded circuits can often tolerate this period without systemic anticoagulation.

ECMO - Extracorporeal Membrane Oxygenation Practice Test

ECMO - Extracorporeal Membrane Oxygenation Practice Test

ECMO - Extracorporeal Membrane Oxygenation ECPR and Special Populations Questions and Answers