Brain Death on ECMO — Summary

1. Introduction & Objectives

  • Objectives:

    • Understand why brain death assessment on ECMO is important.

    • Review the technical process of declaring brain death by neurological criteria.

  • Relevance:

    • Many ECMO patients originate from out-of-hospital cardiac arrest (OHCA).

    • Despite ECMO’s life-saving role, many patients do not survive.

    • ECMO can preserve organs and expand the donor pool, offering collateral benefits through organ donation.

2. ECMO and Organ Donation

  • Organ Shortage: Global demand for organs is rising sharply.

  • ECMO Contribution:

    • Maintains organ perfusion and function, improving graft outcomes.

    • Applicable to ECPR, cardiogenic shock, and ARDS cases.

  • Studies Highlight:

    • ECMO patients show significant potential for organ donation (brain death and circulatory death donors).

    • Emphasizes ethical, humane handling and institutional preparedness.

3. Prerequisites for Brain Death Evaluation

  • Institutional Protocols: Each ECMO center should have internal criteria with neurologist involvement.

  • Preconditions:

    • Confirm catastrophic brain injury via history, imaging, and examination.

    • Exclude confounders: drug effects, hypothermia, intoxication, or hemodynamic instability (MAP >75 mmHg).

    • Consider ECMO’s altered pharmacodynamics — allow sufficient time for drug clearance.

4. Diagnostic Criteria

  • Absence of Cerebral Function: No movement or response to pain; spinal reflexes may persist.

  • Absence of Brainstem Function:

     

    • No pupillary, corneal, vestibular, gag, or cough reflexes.

    • No spontaneous breathing.

     

  • Irreversibility: Condition must be non-recoverable.

5. Apnea Test on ECMO

  • Principle: Elevated CO₂ should trigger breathing in a non–brain-dead patient.

  • Procedure:

    • Reduce sweep gas (0.5–1 L/min) to retain CO₂.

    • Preoxygenate and disconnect from the ventilator (CPAP or oxygen supplement).

    • Obtain baseline and follow-up blood gases (multiple sites for VA/VVA).

    • Positive test: PaCO₂ > 55 mmHg or ≥ 20 mmHg rise with no respiratory effort.

    • Terminate if instability or desaturation occurs.

6. Ancillary Tests

    • EEG: Absence of electrical activity indicates brain death.

    • Cerebral Angiography or Perfusion Scan: No blood flow signifies absent cerebral perfusion.

    • Somatosensory Evoked Potentials: Absence of N20 wave suggests cortical inactivity.

      If Apnea Test Not Feasible:

7. Key Recommendations

  • Establish brain death on ECMO protocols involving neuro experts.

  • Allow 24–48 hours stabilization before testing post–acute phase.

  • Exclude all reversible causes.

  • Perform apnea test ideally twice or with two independent providers.

  • Use ancillary tests when apnea test cannot be safely performed.

Conclusion:

ECMO offers life-saving potential and opportunities for organ donation, but brain death diagnosis requires structured, ethical, and multidisciplinary protocols to ensure accuracy and respect for patients and families

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