Brain Death

Question 1

Definition of brain death

Answer 1

• ‘Irreversible loss of the capacity for consciousness, combined with irreversible loss of the capacity to breathe spontaneously’.
• (Deep coma without spontaneous breathing)

Question 2

What are the steps involved in making a diagnosis of brainstem death?

Answer 2

• Ensuring that certain preconditions have been met
• Excluding reversible causes of apnoeic coma
• Clinical examination confirming brainstem areflexia and documenting persistent apnoea.

Question 3

What are conditions under which the diagnosis of brainstem death should be considered?

Answer 3

1. Patient deep coma, apnea or ventilated at least 24hours
2. Causes of coma is established
3. Irreversible brain damage

Question 4

What are the 3 precondition needed to diagnose brain death?

Answer 4

• First precondition (patient’s consciousness)
  o Pt should be deeply unconscious.
  o No evidence unconscious due to depressant drugs.
  o Exclude primary hypothermia as cause of unconsciousness.
  o Exclude potentially reversible circulatory, metabolic and endocrine disturbances as the cause of continued unconsciousness.
• Second precondition ( patient’s breathing)
  o Pt ventilatilated because spontaneous respiration had become inadequate or had ceased.
  o Exclude muscle relaxants and other drugs (e.g. sedatives) as a cause for the inadequacy or failure of respiration.
  o Exclude neuromuscular-blocking drugs and the persistence of their effects by elicitation of deep tendon reflexes or by demonstration of adequate neuromuscular conduction with a nerve stimulator
• Third precondition
  o No doubt the condition is due to irreversible brain damage of known cause; this invariably means CT of the brain.
  o The criteria for diagnosis of brainstem death are not fulfilled if the primary diagnosis cannot be made

Question 5

Who are eligible to perform brain death test?

Answer 5

• 2 specialist who have been registered for > five years
• At least one is consultant
• Not involve in organ transplant team
• Non-treating doctor
• Examination at separate time
• Death is not pronounced until the 2nd test ( 6 hours apart) has been completed, but the legal time of death is when the first test indicates brainstem death

In Malaysia, Time of Death Declaration: The legal time of death is recorded at the time of the second examination that confirms brain death.

Question 6

List down test needed to confirm brain death?

Answer 6

1) Pupillary reflex – CN II, III
o The pupils fixed and do not respond to bright light

2) Doll eye reflex – CN III, IV (occulocephalic)
o Head is quickly turned to one side and held there.
o In normal pt, eyes deviate to the opposite side of the head, followed by prompt (after 1–2 seconds) realignment of the eyes with the head.

3) Cornea reflex – CN V, VII
o No corneal reflex
o Care should be taken to avoid damage to the cornea otherwise not suitable for donation

4) Motor function (CN V, VII)
o No motor responses within the cranial nerve distribution elicited by adequate stimulation of a somatic area
o No grimacing response to painful stimuli applied to the trigeminal fields (firm supraorbital pressure) or to the limbs.

5) Caloric reflex – CN VI, VIII
Firstly check ext auditory meatus (no perforation, obstruction).
o Vestibulo-ocular reflexes are absent.
o No eye movements after slow injection ice-cold water ( up to 50 cc) into each ear canal over one minute
o The normal response is nystagmus, with the fast component away from the ear tested

6) Gag reflex – CN IX, X
o By a suction catheter passed down the trachea

7) Apneuic test

Pre-exquisite
1. Temperature normal > 35 degree Celcius
2. Systolic pressure > 90mmHg
3. Euvolumic
Normal PCO2 (Arterial PCO2 of 35-45 mm Hg)

o Preoxgenated 100% for 5-10min
o Disconnect ventilator for 10 minutes. Look chest movement and abdomen movement
o ABG - Look PCO2 50mmHg
o Monitor BP, SPO2, PR
o If hypotensive - abort
*Lazarus sign might be positive

*Lazarus sign = reflex movement in brain-dead or brainstem failure patients, which causes them to briefly raise their arms and drop them crossed on their chests (in a position similar to some Egyptian mummies)

• All the test above must be done in ICU *

Question 7

What are Ancillary test for brain death available?

Answer 7

• Reserve for cases where entire exam cannot be done
o Severe facial trauma
o Preexisting pupillary abN – cataract, eye surgery
o Child <1yr

• Cerebral electrical activity
  o EEG
• Cerebral blood flow
  o Angiography (classic contrast angiography, CT angiography,
  o Magnetic resonance angiography and perfusion)
  o Isotope scans (usually with 99Tc-HMPAO)
  o Transcranial Doppler ultrasonography
  o PET with H215O
• Cerebral metabolism
  o PET with labelled glucose or 15O
  o Jugular bulb oxygen saturation
• Cerebral-evoked responses
  o Brainstem auditory-evoked responses
  o Somatosensory-evoked potentials
  o Motor-evoked potentials