ECMO - Extracorporeal Membrane Oxygenation Veno-Arterial (VA) ECMO Management Questions and Answers

Question 1

A patient on peripheral VA ECMO for acute myocardial infarction develops progressive pulmonary edema, a pulse pressure of less than 10 mmHg, and an echocardiogram showing a persistently closed aortic valve. These findings are most indicative of which critical complication?

Accepted Answer

Left ventricular (LV) distension

Answer

The combination of increased afterload from retrograde flow and a severely stunned myocardium can lead to an inability of the left ventricle to eject blood. This causes the aortic valve to remain closed, leading to a dangerous increase in LV end-diastolic pressure and volume (LV distension), which manifests as pulmonary edema and a non-pulsatile arterial waveform.

Question 2

Which of the following findings is the most reliable indicator of sufficient myocardial recovery to begin a weaning trial from VA ECMO?

Accepted Answer

Consistent arterial line pulsatility and an LV outflow tract VTI > 10 cm on echocardiography

Answer

The primary goal of VA ECMO is cardiac support. The most reliable signs of cardiac recovery are the heart's ability to generate its own effective stroke volume. This is demonstrated by a return of consistent pulsatility on the arterial waveform and objective echocardiographic measures like the left ventricular outflow tract velocity time integral (LVOT VTI), with a value >10 cm indicating readiness to wean.

Question 3

A patient on VA ECMO is receiving a heparin infusion with a target aPTT of 60-80 seconds. The most recent aPTT is 110 seconds, and there is new, significant oozing from the cannula insertion sites. Which is the most appropriate immediate action?

Accepted Answer

Decrease or temporarily hold the heparin infusion and re-evaluate

Answer

The patient is both clinically bleeding and has a laboratory value indicating excessive anticoagulation (aPTT above the target range). The most direct and appropriate first step is to reduce or stop the source of the anticoagulation, which is the heparin infusion. While blood products may be needed if bleeding is severe, the primary intervention is to correct the supratherapeutic anticoagulation.

Question 4

In a patient on full-flow peripheral VA ECMO for cardiogenic shock, which hemodynamic pressure is most directly and significantly reduced as a consequence of the circuit's function?

Accepted Answer

Pulmonary Artery (PA) pressure

Answer

VA ECMO functions by draining venous blood from the right atrium, bypassing the right ventricle and the pulmonary circulation entirely, and returning oxygenated blood to the aorta. This diversion of blood flow away from the pulmonary circuit causes a significant reduction in pulmonary artery pressures.

Question 5

A patient on femoral VA ECMO for severe respiratory failure with secondary cardiac dysfunction begins to show signs of myocardial recovery. The monitor shows a right radial SpO2 of 88% while the lower extremity SpO2 is 99%. Which is the most appropriate initial intervention to manage this differential hypoxia (Harlequin syndrome)?

Accepted Answer

Optimize mechanical ventilation by increasing FiO2 and PEEP

Answer

Differential hypoxia occurs when a recovering left ventricle ejects poorly oxygenated blood (due to underlying lung disease) preferentially to the upper body and coronaries. The first-line management is to improve the oxygenation of the blood passing through the native lungs by optimizing ventilator settings, such as increasing the FiO2 and PEEP.

ECMO - Extracorporeal Membrane Oxygenation Practice Test

ECMO - Extracorporeal Membrane Oxygenation Practice Test

ECMO - Extracorporeal Membrane Oxygenation Veno-Arterial (VA) ECMO Management Questions and Answers