Prepared by Dr Lily LL Chang, Dr Arthur CW Lau and Dr WW Yan, Department of Intensive Care, Pamela Youde Nethersole Eastern Hospital, Posted on 28 May 2010

Figure. Equipment for Brainstem death certification
The following illustrated guide refers only to the technical aspect of performing a Brain Death Certification in Hong Kong. For details on other aspects, please refer to the Hong Kong Hospital Authority Brain Death Certification Form (HA 0090/MR), and the most updated version (14th Sep 2009) of the Position Statement of the HKSCCM on Certification of Brain Death (here). The basic principle is to achieve 100% specificity of brainstem death. Difference in practice may exist in different countries.


Diagnosis

Write down the nature of the irremedial structural brain damage, e.g. subarchanoid haemorrhage.
 

Exclusions

Presence of the following four potentially reversible causes of coma must be excluded:

1. Depressant drugs

2. Neuromuscular blocking drugs (muscle relaxants) - see below for instructions to use the nerve stimulator to exclude any residual effect of neuromuscular blocking drugs if they have been given

ulnar n desktop resolution
A peripheral nerve stimulator should always be used to confirm intact neuromuscular conduction Positions of the electrodes for ulnar nerve stimulation (red positive at proximal position, black negative at distal position)

 

Video showing adduction of thumb during stimulation of the ulnar nerve by Train of Four stimulation

  
3. Hypothermia (temperature < 35 C)

4. Metabolic or endocrine disturbances

 
Examinations

1. Pupils reaction to light

 pupil response desktop resolution

Must use a strong enough light source, the light to approach from the side and not directly in front of the pupil, test both eyes for both direct and consensual reflexes. If there is no reaction, the pupils should remain at >= 4 mm in diameters.

 
2. Corneal reflexes

corneal reflex desktop resolution
Touch the cornea using a cotton wool rolled to a tip. Do not just touch the sclera and do not approach in front of the pupil.

 

3. Eye movement on cold caloric testing

inspect eardrum desktop resolution Otoscopic examination before conducting cold caloric test to make sure that the eardrum is intact.

  

ice water desktop resolution caloric test desktop resolution
Prepare iced water for injection into the ear canal Inject at least 20ml of ice water into the ear canal. Normally there will be conjugate movement of both eyes towards the opposite side. Absence means loss of such brainstem reflex



4. Tracheal or gag reflex

gag1 desktop resolution gag2 desktop resolution
Testing the tracheal reflex by moving the ETT in and out Testing the gag reflex by inserting a suction catheter into the oropharynx



5. Test for motor response in the trigeminal nerve distribution to stimulation of face, limbs or trunk.

Look for facial grimacing while performing the following on the face, limbs and trunk

Pressure over eyebrow Over earlobe Over finger bed Over sternum Nipple pinching



6. Respiratory movement with arterial PaCO2>8kPa and pH<7.30


Before the test, while the patient is still on the ventilator, the patient is preoxygenated with 100% for at least 5 minutes. The minute ventilation is kept on the lower side otherwise the apnoea test will have to be prolonged before the PaCO2 can rise to > 8kPa and pH < 7.30. 

Apnoea test: Patient is then disconnected from the mechanical ventilator long enough to ensure that the arterial carbon dioxide tension rises above the threshold for stimulating respiration.

The oxygen supply can be connected to a suction catheter with the suction port closed. It is then inserted into the endotracheal tube up to the tip of the endotracheal tube with oxygen supply set at 6 - 15 L/min. It is important not to cover up the endotracheal opening, otherwise oxygen going in has no where to escape and will result in pneumothorax, pneumomediastinum and subcutaneous emphysema.


check abg desktop resolution
These patients may be moderately hypothermic (35oC-37oC), flaccid, and with a depressed metabolic rate, so that PaCO2 rises only slowly in apnoea (about 0.27kPa/min). They should be disconnected from the mechanical ventilator when their PaCO2 is close to normal. After around 10 to 15 minutes, usually the target PaCO2 and pH will be reached and an ABG can be checked. PaCO2 must be greater than 8.0kPa and arterial pH less than 7.30 as the criteria of a positive apnoea test.


7. If any of the above conditions cannot be satisfied, confirmatory test for intracranial blood flow in both vertebro-basilar and supratentorial circulations should be done.

 


8. The second test can be performed at any time after the first test.


Certification
documentation desktop resolution
Documentation: "We certify that we have assessed this patient and that he/she meets the necessary clinical criteria for the diagnosis of brain death. Name, Position/Rank, Signature, Date of Assessment, Time of Assessment of the 2 doctors must be written down. Date and time of brain death will be documented if all the above criteria for brain death are fulfilled."