Brain Death Criteria [Neurosurgery Wiki]

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====== Brain Death Criteria ======

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{{::brain_death_criteria.png?600|Brain death criteria diagram}}

For individuals under 5 years of age, see: [[brain_death_in_children|Brain death in children]]

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===== 🧠 Recommendations =====

=== 1. Absence of Brainstem Reflexes ===

**a) Ocular examination:**

  * Fixed pupils: no response to bright light  
    → Caution post-[[resuscitation]]; pupil size is not critical (often midposition 4–6 mm, but may vary).  
    → Dilated pupils (≈9 mm) can still be compatible with brain death due to intact cervical sympathetic fibers.

  * Absent [[corneal_reflex|corneal reflexes]]:  
    → Stimulate the cornea, not sclera.

  * Absent [[oculocephalic_reflex|oculocephalic reflex]] (“doll’s eyes”)  
    → Contraindicated if cervical spine is not cleared.

  * Absent [[oculovestibular_reflex|oculovestibular reflex]] (cold calorics):  
    → Instill 60–100 ml of ice water into one ear (contraindicated if tympanic membrane is perforated), head at 30°.  
    → Wait ≥1 minute for eye movement; wait ≥5 minutes before testing the other ear.

**b) Absent [[gag_reflex|oropharyngeal reflex]] (gag reflex)**

**c) No [[cough|cough reflex]]** during bronchial suctioning

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=== 2. Apnea Test ===

See: [[apnea_test|Apnea test]]

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=== 3. Absence of Motor Function ===

**a) No cerebral response to painful auditory or tactile stimuli:**  
  * No purposeful movement of limbs  
  * No eye opening or facial movement  
  * No posturing or seizures

**b) Movements incompatible with brain death:**
  * **True decerebrate/decorticate posturing**  
  * **Seizure activity**

**c) Spinal cord-mediated movements compatible with brain death:**

Examples (documented in literature):
  * Flexor plantar reflexes, withdrawal reflexes  
  * Abdominal or cremasteric reflexes  
  * Complex automatisms:
    - Arm flexion towards face  
    - Sitting up (Lazarus sign)

> ⚠️ In cases of complex movements, **confirmatory ancillary testing is recommended**.

**Cited studies:**
  * Ivan LP. Neurology. 1973; 23:650–652  
  * Turmel A et al. Neurosurgery. 1991; 28:298–302  
  * Heytens L et al. J Neurosurg. 1989; 71:449–451  
  * Ropper AH. Neurology. 1984; 34:1089–1092  
  * Jastremski MS et al. Neurosurgery. 1991; 29:479–480

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===== 🕒 Recommended Observation Periods =====

There is insufficient evidence to define a minimum observation period in all cases.

**a)** When **catastrophic irreversible brain injury** is evident (e.g., massive [[intracerebral_hemorrhage|ICH]], gunshot wound), and no doubt exists in the neurological exam, **ancillary tests are often unnecessary**.

**b)** In clear cases after several hours of observation, a **single neurologic exam** may be sufficient — although some jurisdictions require **two exams by law**.

**c)** In uncertain cases (e.g., [[anoxic brain injury]], hypothermia), longer observation and **ancillary testing** may be appropriate.

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===== 🧾 AAN Guidelines for Brain Death Determination =====

See: [[american_academy_of_neurology_guidelines|American Academy of Neurology Guidelines for Brain Death Determination]]

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===== 🧪 Ancillary Confirmatory Tests =====

See: [[ancillary_confirmatory_tests|Ancillary confirmatory tests for brain death]]

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===== 👶 Pediatric Guidelines =====

See: [[pediatric_brain_death_guideline|Pediatric brain death guideline]]