Before 1968, the determination of the moment of death was done by the cessation of respiratory and cardiac functions which are entirely necessary to maintain the unity of a living being. In 1968 an ad hoc committee at Harvard Medical School, chaired by Sir. Henry Beecher suggested revising the definition of death in a way that would make some patients with devastating neurologic injury suitable for organ transplantation under the dead donor rule. Brain death is a death with certitude, namely the complete and irreversible cessation of all cerebral activity, the person was going to die in any case
     1. Patient should be comatose and on ventilatory support
     2. Functional, reversible causes of a non-functioning brainstem should have been ruled out namely

       a.Shock/ hypotension
       b.Hypothermia -temperature < 32°C
       c. Drugs known to alter neurologic, neuromuscular function and electroencephalographic testing,

           like anaesthetic agents,    neuroparalytic drugs, methaqualone, barbiturates, benzodiazepines,

           high dose bretylium,    amitryptiline, meprobamate, trichloroethylene, alcohols.
      d.Brain stem encephalitis.
      e.Guillain- Barre' syndrome.
      f. Encephlopathy associated with hepatic failure, uraemia and hyperosmolar coma
      g. Severe hypophosphatemia.
      h.The cause of irreversible structural brain damage should be known
      i. Severe head injury.
      j. Hypertensive intracerebral hemorrhage.
      k.Aneurysmal subarachnoid hemorrhage.
      l. Hypoxic-ischemic brain insults.
      m.Fulminant hepatic failure are potential causes of irreversible loss of brain function.
      n. Absent brain stem reflexes
            -> Absence of pupillary reflex response to light
            -> Absence of corneal reflexes

            ->Absence of vestibulo-ocular reflex

            -> Absence of cranial nerve response to pain
            ->Absence of gag and cough ceflexes
Certification of Brain death is by the committee of doctors consisting of
       a. Medical Superintendent of the Hospital
       b. An independent Registered Medical Practitioner nominated by the Medical Superintendent

       c.A Neurologist or Neurosurgeon nominated by Medical Superintendent
       d.The doctor on-duty treating the patient.
Brain death has to be confirmed twice with an interval of 6 hours, before official declaration is done as per the India THO act, 1995 (Form No.8).