brain_death_diagnosis

Brain Death Diagnosis

Brain death is the irreversible cessation of all functions of the entire brain, including the brainstem. It is both a legal and medical definition of death in most countries and serves as the foundation for ethical organ donation.

🧠 Core Clinical Criteria

The clinical diagnosis of brain death requires:

  • Irreversible cause of coma established (e.g., TBI, hemorrhage, anoxia)
  • Absence of confounding factors:
    1. Hypothermia (core temperature > 36°C)
    2. CNS depressants, sedatives, paralytics
    3. Severe metabolic or endocrine disturbances
  • Complete neurological examination, including:
    1. No response to painful stimuli
    2. Absence of brainstem reflexes:
      1. Pupillary light reflex
      2. Corneal reflex
      3. Oculocephalic reflex (“doll’s eyes”)
      4. Oculovestibular reflex (cold calorics)
      5. Gag and cough reflexes
    3. Apnea test: No spontaneous respiration despite a rise in PaCO₂ above 60 mmHg or 20 mmHg over baseline

🧪 Ancillary Tests (When Required)

see Ancillary Confirmatory Tests for Brain Death

🕒 Observation Periods

Depends on age and national regulation:

  • Adults: some protocols require two independent exams, others accept one if criteria are unequivocally met
  • In cases of uncertain prognosis (e.g., anoxia, hypothermia), a longer observation period and/or ancillary testing is recommended

⚖️ Legal and Ethical Considerations

  • Must follow national standards (e.g., AAN [USA], ONT [Spain], AoMRC [UK])
  • Documentation must include:
    1. Established irreversible coma
    2. Absence of brainstem reflexes
    3. Apnea test results
    4. Time of death declaration

👨‍⚕️ Who Can Perform the Diagnosis?

Typically:

  • Two licensed, independent physicians
  • Must not be involved in transplant team
  • Often includes neurologists, intensivists, or neurosurgeons

Common Pitfalls in Diagnosis

  • Spinal movements postmortem: e.g., facial twitching, finger tremors, or the “Lazarus sign” (sitting up) – all mediated by the spinal cord
  • False appearance of breathing: Ventilators may auto-trigger due to arterial pulsations or mechanical artifacts, not genuine respiration

Brain Death: Diagnosis vs. Criteria

✅ Brain Death Diagnosis

Refers to the act or process of determining that a person is brain dead based on clinical and/or ancillary findings.

Examples:

  • “The brain death diagnosis must comply with legal protocols.”
  • “Diagnosis was confirmed following a complete exam and apnea testing.”

✅ Brain Death Criteria

Refers to the clinical standards or protocol elements used to make the diagnosis.

Examples:

  • “The patient fulfilled all brain death criteria.”
  • “Protocols define the minimum criteria to establish brain death.”

🧠 Comparison Table

Term Meaning Use Case
Brain death diagnosis Act of declaring death via neurological criteria Legal documentation, clinical act
Brain death criteria Required clinical or test-based standards Protocols, medical education

Brain Death Determination vs. Diagnosis

While related, these terms describe different stages:

🧪 Brain Death Determination

Describes the step-by-step clinical protocol:

  • Neurological exam
  • Apnea test
  • Ancillary testing (if needed)
  • Observation and legal documentation
Example: “Brain death determination includes all required confirmatory steps.”

✅ Brain Death Diagnosis

Refers to the final legal declaration that the patient is dead based on the determination process.

Example: “Diagnosis of brain death was made at 08:22 by the attending physician.”

🧠 Summary Table

Term Definition Emphasis
Brain Death Determination Protocol used to confirm brain death Process and steps
Brain Death Diagnosis Declaration based on completed protocol Legal and clinical outcome

📚 Source

* Neurology. 2010 Jun 8;74(23):1911. doi:10.1212/WNL.0b013e3181e242a8 

→ https://n.neurology.org/content/74/23/1911

🔗 See Also

  • brain_death_diagnosis.txt
  • Last modified: 2025/06/24 22:05
  • by administrador