Anticoagulation During ECMO: Challenges and Protocols
1. Rationale for Anticoagulation
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Prevent thrombosis in patient and ECMO circuit.
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Balance between clotting risks (systemic emboli, oxygenator clot) and bleeding risks.
2. Anticoagulation Protocols
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Heparin is standard: bolus at cannulation, then continuous infusion.
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Targets vary by center:
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ACT (80–180 sec), aPTT, anti-Xa.
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Platelets maintained >50–60.
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Other monitoring: daily clotting profile, fibrinogen, D-dimer.
3. Monitoring Methods
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ACT: rapid bedside, but altered by hypothermia/hemodilution.
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aPTT: widely used, but influenced by sepsis, liver disease.
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Anti-Xa: measures heparin activity, may reveal AT-III deficiency.
4. High Bleeding Risk Patients
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Reduce anticoagulation targets or withhold completely.
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Maintain high ECMO flow to reduce stasis/clot risk.
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Vigilant circuit inspection, D-dimer, platelets, hemoglobin.
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MDT discussion essential for daily decisions.
5. VV vs VA ECMO
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VV ECMO: lower systemic clot risk, more flexible anticoagulation.
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VA ECMO: bypasses lungs, higher risk of systemic emboli → stricter targets.
6. Complications
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Bleeding: common at cannula sites, GI tract, or intracranial (neurosurgical options limited).
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Thrombosis: circuit clot, systemic emboli, valve thrombus.
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Circuit change may be required in clotting/hemolysis.
7. Heparin-Induced Thrombocytopenia (HIT)
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Suspect with >50% platelet drop, new thrombosis.
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Confirm with antibody and functional assays.
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Stop all heparin (including flushes, coated lines).
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Switch to Argatroban or Bivalirudin; monitor with aPTT.
8. Key Takeaways
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Anticoagulation in ECMO is a dynamic balance.
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Bleeding complications are more common, but thrombotic events are often catastrophic.
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Protocol-driven, MDT-based management is essential to safely support patients.