• 1.0 INTRODUCTION

The advent of effective artificial cardiopulmonary support has created new concepts about the diagnosis of death in the last few decades.  Previously, cessation of heart and lung functions were the only basis for diagnosing death whether the initial failure occurred in the brain, the heart, the lungs or elsewhere in the body.  Since the cardiac and pulmonary functions can be sufficiently maintained artificially, even when the brain-is irreversibly damaged, there have to be other criteria to define death.  Thus came the concept of brain-death and the need for definite neurological criteria that must be used to assess whether the brain functions have ceased irreversibly.

The concept of brain death was first reported in 1959 by a group of French physicians.  Later during the same year, Mollart and Goulon called this condition Coma depasse, which means a state beyond coma.  In 1968, the Ad-Hoc Committee of Harvard Medical School was appointed to examine the definition of brain death and the Harvard Criteria were adopted in the USA.  In 1971, a major conceptual advance occurred when Mohandas and Chou, two Minneapolis neurosurgeons, made the challenging suggestion that in patients with known irreparable intra-cranial lesions, irreversible damage to the brain-stem was the point of no return.  Thus evolved the concept of brain-stem death.  The criteria were laid down for the diagnosis and became known as the Minnesota Criteria.  This stimulated much later work particularly in the UK.  The UK code in 1976 and the addendum to the original report in 1979, described diagnosis of brain­stem death and emphasized the need for observing strict pre-conditions and necessary exclusions without which the diagnosis of brain-death cannot be considered.

In the USA, further important developments took place in 1981, thirteen years after the Harvard Criteria was adopted.  A large panel of physicians from various specialities contributed to the report on The Diagnosis of Death to the President's Commission for the Study of Ethical Problems in Medicine and Biomedical and Behavioural Research.  They recommended uniform criteria for the diagnosis of brain death and defined brain death as irreversible cessation of all functions of the entire brain, including the brain-stem.  Accordingly, the irreversibility of brain damage is recognised when evaluation discloses all of the following:

1. An established cause of coma sufficient to account for the loss of brain function.
   
   

2. Exclusion of the possibility of recovery of any brain function.
   
   

3. The persistent cessation of all brain functions during an appropriate period of observation and/or a trial of therapy.  This may take 6-24 hours depending on the availability of different confirmatory tests such as EEG, evoked potentials and four vessel cerebral angiography.  For patients suspected to have conditions such as drug intoxication, metabolic derangements and hypothermia, a longer period of observation and persistence of cessation of brain functions despite correction of these abnormalities are needed in order to declare them brain-dead.  Infants and children before puberty also need longer observation periods.
   

The concept of brain death is specific.  It does not apply to patients existing in a persistent vegetative state or to other severe degrees of brain damage from causes such as metabolic derangements, drug intoxication, etc. (Figure. 1).