CCP Mechanical Circulatory Support & ECMO Management 1 — Questions and Answers
Question 1: What is the primary indication for veno-arterial (VA) ECMO in the cardiac surgical setting?
- Respiratory failure with normal cardiac function
- Cardiogenic shock with refractory hemodynamic instability (Correct answer)
- Pulmonary hypertension without cardiac involvement
- Chronic heart failure awaiting transplant evaluation
Correct answer: Cardiogenic shock with refractory hemodynamic instability
VA-ECMO provides both cardiac output support and gas exchange, making it the appropriate intervention for cardiogenic shock when conventional therapies fail.
Question 2: In peripheral VA-ECMO, oxygenated blood is returned to which vessel?
- Superior vena cava
- Pulmonary artery
- Femoral artery (Correct answer)
- Femoral vein
Correct answer: Femoral artery
In peripheral VA-ECMO, the oxygenated blood is returned via the femoral artery so it enters the systemic arterial circulation to perfuse the body.
Question 3: What is the typical activated clotting time (ACT) target range maintained during ECMO support?
- 80–120 seconds
- 160–200 seconds (Correct answer)
- 300–350 seconds
- 400–450 seconds
Correct answer: 160–200 seconds
During ECMO, the ACT is typically maintained at 160–200 seconds, which provides adequate anticoagulation to prevent circuit thrombosis while minimizing bleeding risk.
Question 4: Which complication arises specifically from the retrograde aortic flow generated by femoral VA-ECMO?
- Venous air embolism
- Left ventricular distension (Correct answer)
- Oxygenator membrane failure
- Pulmonary edema from circuit overpressure
Correct answer: Left ventricular distension
Retrograde femoral arterial return increases left ventricular afterload; if the native heart cannot eject effectively, the LV becomes distended, raising wall stress and myocardial oxygen demand.
Question 5: In the context of mechanical circulatory support, what does a 'bridge to transplant' (BTT) strategy mean?
- Permanent cardiac replacement with a device
- Temporary support to stabilize a patient until a donor organ becomes available (Correct answer)
- Weaning from mechanical ventilation using device support
- Use of an IABP to treat massive pulmonary embolism
Correct answer: Temporary support to stabilize a patient until a donor organ becomes available
BTT refers to using temporary mechanical support (such as ECMO or an LVAD) to keep a patient hemodynamically stable until a suitable cardiac donor organ is available.
Question 6: Veno-venous (VV) ECMO is specifically indicated for which clinical scenario?
- Cardiac failure with preserved pulmonary function
- Combined cardiac and respiratory failure
- Severe respiratory failure with preserved cardiac function (Correct answer)
- Pulmonary hypertension requiring cardiac unloading
Correct answer: Severe respiratory failure with preserved cardiac function
VV-ECMO cannulates only the venous system to oxygenate and decarbonate blood, relying entirely on the native heart for circulation, making it appropriate when cardiac function is preserved.
Question 7: Which finding most reliably indicates successful weaning from VA-ECMO support?
- Increasing ECMO flow requirements to maintain MAP
- Stable hemodynamics as ECMO flows are progressively reduced (Correct answer)
- Rising SvO2 only at high ECMO flow rates
- Decreasing arterial oxygen saturation with flow reduction
Correct answer: Stable hemodynamics as ECMO flows are progressively reduced
Successful weaning is confirmed when the patient maintains adequate blood pressure and cardiac output as ECMO flows are gradually lowered, demonstrating that native cardiac function has recovered.
CCP Mechanical Circulatory Support & ECMO Management 1
What is the primary indication for veno-arterial (VA) ECMO in the cardiac surgical setting?