CES ECMO Complications & Management 1 — Questions and Answers
Question 1: Harlequin syndrome (differential hypoxia) occurs in which ECMO configuration?
- VV ECMO with dual-lumen cannula
- Peripheral VA ECMO with femoral cannulation and recovering cardiac function (Correct answer)
- Central VA ECMO via the aorta
- VV ECMO with bi-caval dual-lumen cannula
Correct answer: Peripheral VA ECMO with femoral cannulation and recovering cardiac function
Harlequin syndrome occurs in peripheral VA ECMO when the recovering heart ejects deoxygenated blood into the aorta, competing with retrograde oxygenated ECMO flow.
Question 2: What is the best monitoring strategy to detect Harlequin syndrome early?
- Continuous SvO2 monitoring at the drainage cannula
- Right-hand (pre-ductal) pulse oximetry combined with arterial blood gas from the right radial artery (Correct answer)
- Bilateral lower limb SpO2 comparison
- Continuous end-tidal CO2 monitoring
Correct answer: Right-hand (pre-ductal) pulse oximetry combined with arterial blood gas from the right radial artery
Right radial arterial ABG and right-hand SpO2 reflect the coronary and cerebral circulation, revealing upper body hypoxia in Harlequin syndrome.
Question 3: Neurological complications are most common in which ECMO patient population?
- Adults on VV ECMO for ARDS
- Neonates on VA ECMO (Correct answer)
- Adults on VA ECMO for post-cardiac arrest
- Pediatric patients on VV ECMO
Correct answer: Neonates on VA ECMO
Neonates on VA ECMO have the highest rates of neurological complications including IVH, stroke, and seizures due to their vulnerable developing brains.
Question 4: Acute hemolysis on ECMO is best indicated by which laboratory finding?
- Rising LDH and plasma-free hemoglobin > 50 mg/dL (Correct answer)
- Falling platelet count
- Rising serum creatinine
- Elevated direct bilirubin
Correct answer: Rising LDH and plasma-free hemoglobin > 50 mg/dL
Elevated LDH and plasma-free hemoglobin above 50 mg/dL are the hallmark laboratory indicators of significant hemolysis in ECMO circuits.
Question 5: Chatter (vibration/cavitation) in the drainage tubing most commonly indicates:
- Oxygenator thrombosis
- Hypovolemia or high resistance at the drainage cannula causing inlet suction (Correct answer)
- Excessive circuit flow rates
- Air entrainment from the venous access site
Correct answer: Hypovolemia or high resistance at the drainage cannula causing inlet suction
Drainage tubing chatter reflects excessive inlet suction, typically caused by hypovolemia, cannula malposition, or high drainage resistance.
Question 6: The most common infectious complication in ECMO patients is:
- Candida bloodstream infection
- Ventilator-associated pneumonia (Correct answer)
- ECMO circuit-related bloodstream infection
- Urinary tract infection
Correct answer: Ventilator-associated pneumonia
Ventilator-associated pneumonia (VAP) remains the most frequent infection complication in ECMO patients due to prolonged mechanical ventilation requirements.
CES ECMO Complications & Management 1
Harlequin syndrome (differential hypoxia) occurs in which ECMO configuration?