i) Electroencephalogram (EEG)

EEG should show electrocerebral silence.  Recording is to be done for at least 30 minutes and must conform with the criteria given in EEG guidelines (Appendix III).  If the patient has hypothermia, he/she must be warmed-up before conducting EEG examination.


ii) Angiography

Demonstration of absence of intracranial arterial circulation by four-vessel angiography is a confirmatory test of brain death for adults and children.  In children, a cerebral radionucleide angiogram (CRAG) also confirms cerebral death by demonstrating the lack of visualization of the cerebral circulation.  A technically satisfactory CRAG that demonstrates arrest of carotid circulation at the base of the skull and absence of intracranial arterial circulation can be considered confirmatory of brain­ death, even though there may be some visualization of the intracranial venous sinuses.

The indications for angiography are:

1. EEG is either not available or cannot be interpreted due to technical problems. In this case, the clinical examination and apnea test are done by the examiners before the angiography.
   
   

2. The cause of death cannot be determined with absolute certainty.
   
   

3. Metabolic derangement, shock or hypothermia cannot be corrected of intensive therapy.
   
   

4. Difficulty in convincing the relatives about the brain-death of their In all these cases, demonstration of absence of cerebral blood flow proves that the brain is irreversibly damaged.
   

1. Brain-stem auditory evoked potentials.
   The typical findings of brain death is preservation of wave I and loss of all other waves.  It has only a limited role and only confirms the loss of brain-stem function, which can as well be tested clinically.
   
   

2. Demonstration of absence of cerebral blood flow by other methods.  This is done by doing one of the following tests:
   

1. Dynamic CT scan of brain.
   
   
2. Isotope brain scan.
   
   

1. Avoid hypoxia which could damage the brain further.
   
   

2. Ensure that PaCO2 builds up to a critical level of 6.7-8.1 kPa (50-60 mm Hg) by the end of disconnection period.  This is a sufficient stimulus to the respiratory center in a functioning brain-stem.
   
   

1. Pre-oxygenate with 100% 02 for 10 minutes.  Increase the inspired frac­tion of oxygen (FI02) without changing the ventilation rate.
   
   

2. Disconnect the patient from ventilator and supply a continuous flow of humidified 100% 02 at the rate of 6 liters/min through an intra-tracheal catheter placed at the carina.  In children, a flow of 1.5-2 liters/min can be used.  Make sure that the catheter is thin enough as not to block the airway.  Pulse oximeter is recommended to be used throughout the apnea testing.
   
   

3. Maintain disconnection for 10 minutes while observing the patient to see if there is any attempt to breathe.  Draw blood for ABG to check the final PaCO2 and record this value.  The PaCO2 must be above 8.1 kPa (60 mm Hg) in adults and 7.6 kPa (55 mm Hg) in children.
   
   Apnea test is considered positive when no respiratory movements have occurred during the disconnection period.