ECMO Complications and Troubleshooting 3 — Questions and Answers
Question 1: During ECMO, the team notices pink frothy fluid in the sweep gas exhaust. What does this indicate?
- Normal condensation in the sweep gas line
- Plasma leak through the oxygenator membrane (Correct answer)
- Air leak in the venous drainage cannula
- Retrograde flow in the circuit
Correct answer: Plasma leak through the oxygenator membrane
Pink frothy fluid in the sweep gas exhaust indicates plasma leakage across the oxygenator membrane, which can reduce gas exchange efficiency and require oxygenator replacement.
Question 2: A VA-ECMO patient on full support suddenly develops pulsatile arterial waveforms with increased mean arterial pressure. This most likely indicates:
- Circuit malfunction reducing flow
- Recovery of native cardiac function (Correct answer)
- Aortic valve regurgitation worsening
- Systemic hypertension crisis
Correct answer: Recovery of native cardiac function
Return of pulsatility on VA-ECMO signifies improved native cardiac contractility, which is a positive sign of cardiac recovery.
Question 3: An ECMO patient develops hemoglobinuria. The initial management step should be to:
- Immediately discontinue ECMO
- Increase urine output with fluids and loop diuretics to protect kidneys (Correct answer)
- Start plasmapheresis
- Reduce anticoagulation to stop hemolysis
Correct answer: Increase urine output with fluids and loop diuretics to protect kidneys
Hemolysis-induced hemoglobinuria can cause acute kidney injury; aggressive diuresis and urine alkalinization help protect renal tubules while the hemolysis source is investigated.
Question 4: Plasma-free hemoglobin (pfHgb) is measured at 800 mg/dL in an ECMO patient. What circuit issue should be investigated first?
- Air in the circuit
- High pump speed causing cavitation and RBC destruction (Correct answer)
- Oxygenator clotting
- Venous line kinking
Correct answer: High pump speed causing cavitation and RBC destruction
Elevated pfHgb indicates hemolysis, commonly caused by excessive pump speed generating shear stress that destroys red blood cells.
Question 5: A patient on ECMO develops fever to 39.8°C with positive blood cultures for Candida. The most appropriate step regarding the ECMO circuit is:
- Continue current circuit and treat with antifungals only
- Change the entire ECMO circuit and cannulas (Correct answer)
- Add antifungal coverage to circuit priming solution
- Increase circuit flows to reduce stasis
Correct answer: Change the entire ECMO circuit and cannulas
Fungal bloodstream infections in ECMO patients require circuit and cannula change, as biofilm on surfaces cannot be sterilized with systemic antifungals alone.
Question 6: Differential hypoxia (Harlequin syndrome) in VA-ECMO via femoral cannulation is characterized by:
- Hypoxia in the lower extremities only
- Oxygenated upper body from native lungs and hypoxic lower body from ECMO
- Oxygenated lower body from ECMO and hypoxic upper body from native lungs (Correct answer)
- Bilateral upper and lower extremity cyanosis
Correct answer: Oxygenated lower body from ECMO and hypoxic upper body from native lungs
In femoral VA-ECMO, oxygenated ECMO blood enters the aorta retrogradely and perfuses the lower body, while the upper body receives deoxygenated blood from the recovering but still-dysfunctional native lungs.
Question 7: During ECMO transport, the centrifugal pump controller alarms 'low flow' and flow drops to 0.5 L/min. The first action should be:
- Increase RPM to maximum
- Assess for tubing kinks, positional cannula obstruction, or hypovolemia (Correct answer)
- Clamp both cannulas and perform emergency CPR
- Administer 1L normal saline rapidly through the venous limb
Correct answer: Assess for tubing kinks, positional cannula obstruction, or hypovolemia
Low flow during transport is most commonly due to mechanical obstruction from kinked tubing or positional cannula issues, and a systematic circuit check must occur before escalating interventions.
ECMO Complications and Troubleshooting 3
During ECMO, the team notices pink frothy fluid in the sweep gas exhaust.
What does this indicate?