ECMO Veno-Arterial (VA) ECMO Management 4 — Questions and Answers
Question 1: What is the most common cannulation site for peripheral VA ECMO in adults?
- Right internal jugular vein and subclavian artery
- Femoral vein and femoral artery (Correct answer)
- Femoral vein and axillary artery
- Femoral vein and radial artery
Correct answer: Femoral vein and femoral artery
Femoral vein to femoral artery cannulation is the most common approach for peripheral VA ECMO due to accessibility and speed of insertion.
Question 2: Which patient population may benefit most from axillary artery VA ECMO cannulation over femoral arterial cannulation?
- Patients with severe peripheral vascular disease or aortic insufficiency (Correct answer)
- Patients with septic cardiomyopathy
- Pediatric patients under 10 kg
- Patients with active gastrointestinal bleeding
Correct answer: Patients with severe peripheral vascular disease or aortic insufficiency
Axillary artery cannulation is preferred in patients with severe femoral/iliac vascular disease or significant aortic insufficiency, and it also provides antegrade upper body perfusion.
Question 3: What does a sudden drop in the ECMO sweep gas FiO2 setting achieve during management?
- Increases CO2 removal
- Decreases oxygen delivery to the patient
- Reduces oxygenation to test native lung function (Correct answer)
- Improves circuit priming
Correct answer: Reduces oxygenation to test native lung function
Reducing sweep gas FiO2 (a 'sweep trial') tests the native lung's ability to oxygenate blood, used during VV ECMO weaning assessments.
Question 4: In VA ECMO, the drainage cannula is typically positioned in which location?
- Superior vena cava near the right atrium
- Right atrium via femoral vein (Correct answer)
- Inferior vena cava at the hepatic vein level
- Left atrium via transseptal puncture
Correct answer: Right atrium via femoral vein
The venous drainage cannula tip is ideally positioned at the right atrial/IVC junction via femoral vein to maximize venous return.
Question 5: Which cardiac rhythm is most concerning when attempting to wean a patient from VA ECMO support?
- Sinus tachycardia at 110 bpm
- Atrial fibrillation with controlled ventricular rate
- Ventricular fibrillation (Correct answer)
- First-degree AV block
Correct answer: Ventricular fibrillation
Ventricular fibrillation indicates no effective native cardiac output, making weaning impossible and requiring immediate defibrillation or continuation of full ECMO support.
Question 6: A patient on VA ECMO develops sudden bright red blood in the ECMO circuit tubing after a position change. This most likely represents:
- Oxygenator malfunction causing over-oxygenation
- Accidental connection of the drainage and return lines (Correct answer)
- Air entrainment causing oxygenated appearance
- Hemolysis producing red-tinged plasma
Correct answer: Accidental connection of the drainage and return lines
Bright red blood in the drainage line (which should be dark venous blood) suggests the drainage and return cannulas have been accidentally switched, a life-threatening error.
Question 7: What is the significance of a widening pulse pressure on the arterial line of a VA ECMO patient over 48 hours?
- Worsening aortic regurgitation from the arterial cannula
- Evidence of myocardial recovery with improving native cardiac output (Correct answer)
- Circuit recirculation causing venous mixing
- Sepsis-induced peripheral vasodilation
Correct answer: Evidence of myocardial recovery with improving native cardiac output
Widening pulse pressure indicates the native heart is generating increasing stroke volume, which is a positive sign of myocardial recovery during VA ECMO.
ECMO Veno-Arterial (VA) ECMO Management 4
What is the most common cannulation site for peripheral VA ECMO in adults?