ECMO Weaning and Decannulation 3 — Questions and Answers
Question 1: Which hemodynamic goal during a VA-ECMO weaning trial best predicts successful decannulation?
- Maintaining MAP > 65 mmHg on low-dose vasopressors with ECMO flow ≤ 1.5 L/min (Correct answer)
- MAP > 80 mmHg on high-dose norepinephrine at full ECMO flow
- Heart rate < 60 bpm with no vasopressor support
- CVP < 5 mmHg and PCWP < 8 mmHg at full flow
Correct answer: Maintaining MAP > 65 mmHg on low-dose vasopressors with ECMO flow ≤ 1.5 L/min
Hemodynamic stability with minimal vasopressor support at low ECMO flows demonstrates sufficient native cardiac output to sustain perfusion.
Question 2: In neonatal ECMO for meconium aspiration syndrome, the most important criterion indicating readiness to wean is:
- Chest X-ray clearance of all opacities
- Decreasing oxygen requirement and improving native lung compliance on ventilator (Correct answer)
- Normalization of serum lactate to < 1.0 mmol/L
- Birth weight exceeding 3.5 kg
Correct answer: Decreasing oxygen requirement and improving native lung compliance on ventilator
Improved pulmonary compliance and reduced FiO2 requirement on the ventilator indicate recovery of native lung function in neonates.
Question 3: After VV-ECMO decannulation via the internal jugular vein, the patient develops acute hypoxia with absent breath sounds on the right. The most likely complication is:
- Pulmonary embolism from cannula thrombus
- Pneumothorax from inadvertent pleural injury during cannula removal (Correct answer)
- Air embolism through the cannula site
- Right main-stem bronchus intubation
Correct answer: Pneumothorax from inadvertent pleural injury during cannula removal
Pneumothorax is a recognized complication of internal jugular cannula removal, especially if the patient coughs or Valsalvas during the procedure.
Question 4: During gradual flow reduction in VV-ECMO weaning, which laboratory value should be monitored most closely to detect inadequate native lung CO2 clearance?
- Serum bicarbonate
- Arterial PaCO2 (Correct answer)
- Venous SvO2 from the drainage cannula
- Serum lactate
Correct answer: Arterial PaCO2
Rising arterial PaCO2 during sweep reduction signals that native lungs cannot clear CO2 sufficiently to sustain the wean.
Question 5: A patient being weaned from VA-ECMO develops LV distension confirmed by echo. Before decannulation, the priority intervention is:
- Increase ECMO flow to decompress the ventricle
- Insert an Impella or intra-aortic balloon pump to unload the LV (Correct answer)
- Reduce vasopressor support to decrease afterload
- Perform urgent aortic valve replacement
Correct answer: Insert an Impella or intra-aortic balloon pump to unload the LV
LV distension during VA-ECMO unloading failure requires a dedicated LV unloading device (Impella or IABP) to prevent pulmonary edema and myocardial injury.
Question 6: Which strategy is recommended to minimize the risk of air embolism during percutaneous VV-ECMO decannulation via the femoral vein?
- Remove the cannula rapidly during peak inspiration
- Place the patient in Trendelenburg position and remove cannula during expiration or Valsalva (Correct answer)
- Clamp the cannula 5 cm proximal to the skin before removal
- Apply negative pressure to the cannula lumen during withdrawal
Correct answer: Place the patient in Trendelenburg position and remove cannula during expiration or Valsalva
Trendelenburg positioning and removal during expiration increases venous pressure at the site, reducing the risk of air entrainment.
Question 7: After successful decannulation from VA-ECMO, anticoagulation management typically involves:
- Immediate discontinuation of all anticoagulation for 72 hours
- Continuation of therapeutic anticoagulation per underlying cardiac condition and thromboembolic risk (Correct answer)
- Transition to antiplatelet therapy only, regardless of underlying condition
- High-dose heparin infusion for 48 hours to prevent rebound thrombosis
Correct answer: Continuation of therapeutic anticoagulation per underlying cardiac condition and thromboembolic risk
Post-decannulation anticoagulation is individualized based on the underlying cardiac pathology, residual thrombus risk, and bleeding status.
ECMO Weaning and Decannulation 3
Which hemodynamic goal during a VA-ECMO weaning trial best predicts successful decannulation?