Introduction

Since ancient times, death is said to have occurred at the moment when all vital signs have stopped permanently. For many centuries, death was signalled by the loss of breathing and only after the stethoscope was invented in the early 19th century, did the cessation of a beating heart take prominence. While in recent times there have been noteworthy technological developments in the areas of ventilation, control of circulation and management of electrolyte disturbances, there has also been a ‘price to pay’ for the improved survival rates recorded.

The immediate consequence of either cardiac or respiratory arrest is death of the brain. However, when the brain dies first, the use of a ventilator and inotropic drugs might substitute lost function with the heart continuing to beat for many days. The process of dying is in this manner, is thus prolonged and distorted. Family and friends suffer much distress while futile interventions continue to rob the patient of a death with dignity.

Definition

Brain Death is a state when the function of the brain as a whole, including the brainstem is irreversibly lost.

Criteria

This is a clinical diagnosis determined by strict neurological criteria and accounts for only 1% of all deaths. In Malaysia, a Brain Death Committee was first formed in 1992 and published the Consensus Statement on Brain Death in 1993. The consensus was reviewed and revised in 2003. As part of the guidelines, there are preconditions to satisfy, exclusions to rule out and clearly outlined diagnostic criteria to strictly comply with before brain death is declared. Two clinical specialists, who have been deemed competent through training and experience and are authorised by their respective hospitals to certify brain death, will assess the patient independently. The whole process is repeated after a period of at least 6 hours after the first assessment, though not necessarily by the same pair of specialists. The time of death is at the time of the 2nd testing.

Recognition and acceptance

A person certified as brain dead is dead. The brain is after all the organ that determines whether the organism functions as a whole or not and its functions are irreplaceable by machines. Therefore, the brain is the ultimate organ that determines life and death.

Diagnosis of Brain Death :

Preconditions

All are to be fulfilled

1. Patient is in deep coma, unable to breathe on his / her own (apnoeic) and on ventilator, for at least 12 hours prior to assessment.
2. The cause of coma is fully established and sufficient to explain the status of the patient.
3. There is irremediable brain damage.

Exclusions

1. Coma due to metabolic or endocrine disturbance, drug intoxication and primary hypothermia (core temperature of < 32°C / 90°F)
2. Guillain-Barré Syndrome and Locked-in Syndrome
3. Coma of undetermined cause
4. Preterm neonates

Diagnostic Criteria

All are to be fulfilled

1. Deep coma, unresponsive and unreceptive, Glasgow Coma Score (GCS) 3/15
2. Absent brainstem reflexes(measures reflex pathways in a rostral-to-caudal direction) confirmed by the following tests:-
   • Pupillary light reflex – No response to bright light bilaterally
   • Oculo-cephalic reflex (Doll’s eye response) – Absent eye movement
   • Motor response in cranial nerve distribution – No grimacing seen
   • Corneal reflex – No blinking response
   • Vestibulo-ocular reflex (Caloric Test) – No tonic deviation of eyes to cold caloric stimulus
   • Oro-pharyngeal reflex – Absent gag response
   • Tracheo-bronchial reflex – Lack of cough response to bronchial suctioning
3. Apnoea confirmed by apnoea test – No respiratory effort with a Pa CO2 of > 60mmHg

Other considerations

Patients who do not meet ALL the above criteria shall not be considered for brain death certification and such certification must ONLY be done in areas of the hospital with full facilities for intensive cardio-pulmonary care of comatose patients.

For children, additional guidelines required are in two areas, namely :

1. The interval between two examinations is lengthened depending on the age of the patient
   • 7 days – 2 months : 48 hours
   • 2 months – 1 year : 24 hours
   • > 1 year : 12 – 24 hours
2. An ancillary test, the electroencephalography (EEG) is recommended for those less than one year old.

If certain aspects of the clinical tests cannot be reliably performed or evaluated then the consensus outlines the ancillary laboratory tests that may be useful in such situations.

Ancillary investigations used

1. Conventional angiography – to detect the absence of intracerebral filling of the intracranial arteries at the entry into the skull
2. Transcranial Doppler Ultrasonography – to detect the absence of cerebral blood flow
3. Nuclear imaging – to detect the absence of cerebral perfusion or “empty skull” sign
4. Electroencephalography (EEG) – to confirm no brain electrical activity during at least 30 minutes of recording that must adhere to strict technical specifications for brain death.

Recommendations

The Brain Death guidelines shall be reviewed every 5 – 10 years.

Reference

Consensus Statement on Brain Death 2003 (Ministry Of Health, Academy of Medicine Malaysia & Malaysian Society of Neurosciences)