Death is defined variably (or not defined at all) in jurisdictions around the world, but are mostly similar. What follows below are the two types of determination of death, as recommended in the ANZICS Statement on Death and Organ Donation

Neurological Determination of Death

Preconditions

1. Known cause of permanent loss of brain function
2. Observation period prior to neurological determination of death
   • 4-hour period
     • LONGER if hypoxic-ischaemic encephalopathy
     • ≥24h post ROSC or post-rewarming to 35^oC after ≥6h of hypothermia
   • GCS 3
   • Pupils non-reactive
   • absent cough/tracheal reflexes
   • apparent apnoea on ventilator
3. Specific preconditions
   • Temperature adequate: hypothermia not present (Temp ≥35^oC)
   • BP adequate (eg MAP ≥60mmHg, SBP ≥90mmHg in adult)
   • Unsedated: Sedative drug effects are excluded
   • No severe electrolyte, metabolic or endocrine disturbance
   • Paralysis absent: Neuromuscular function intact, high c-spine injury excluded
   • Eye and Ear: It is possible to asses brainstem reflexes (one eye & one ear)
   • Safe for Apnoea: It is possible to perform apnoea testing

Clinical testing

1. No motor response in (BOTH)
   • facial nerve distribution to pain in face or upper limbs, AND
   • upper limbs to pain in trigeminal nerve distribution
2. Pupils are unresponsive to light
3. Corneal reflexes are absent
4. Gag (pharyngeal) reflex is absent
5. Cough (tracheal) reflex is absent
6. Oculocaloric (vestibulo-ocular) reflex is absent
7. Apnoea test is positive: breathing absent despite P_aCO₂ >60mmHg AND arterial pH <7.3
   • IF chronic hypercarbia, rise in P_aCO₂ must be >20mmHg from baseline, PLUS an arterial pH <7.3

Cranial Nerves Tested (II – X)

Reflex	Afferent Limb	Efferent Limb
Pupillary reflex	CN II – Optic nerve	CN III – Oculomotor nerve
Corneal reflex	CN V – Trigeminal nerve (ophthalmic nerve)	CN VII – Facial nerve (orbicularis oculis)
Trigeminal pain – supraorbital pressure	CN V – Trigeminal nerve	CN VII – Facial nerve (for grimace)
Oculocaloric reflex	CN VIII – Vestibulocochlear nerve	CNs III, IV & VI – Oculomotor, Trochlear & Abducens nerves
Gag reflex	CN IX – Glossopharyngeal nerve	CN X – Vagus nerve
Cough reflex	CN X – Vagus nerve	CN X – Vagus nerve (& Phrenic, spinal motor nerves)

Radiological testing

1. Preconditions
   • GCS 3
   • Pupils non-reactive
   • Cough (tracheal) reflex absent
   • Apnoea, no breathing effort
2. Perfusion absent, demonstrated by appropriate study
   • Intra-arterial angiography
   • Nuclear medicine perfusion scan (Tc-99m HMPAO radionuclide cerebral perfusion scan)
   • CT Angiography
3. certified by 2 doctors (≥PGY5, one is a specialist)

Circulatory Determination of Death

• Simply, the absence of circulation for 5 minutes, confirmed by brief clinical examination
  • Flat art line for 5 minutes despite ECG, or
  • isoelectric ECG for 5 minutes if no art line