brain_death_criteria

Brain Death Criteria

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.

→ Stimulate the cornea, not sclera.

→ Contraindicated if cervical spine is not cleared.

→ 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 oropharyngeal reflex (gag reflex)

c) No cough reflex during bronchial suctioning


2. Apnea Test

See: Apnea test


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:
    1. Arm flexion towards face
    2. 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

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

a) When catastrophic irreversible brain injury is evident (e.g., massive 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.


  • brain_death_criteria.txt
  • Last modified: 2025/06/24 21:55
  • by administrador