Brain death

Brain Death


This guide is intended to help answer some of the questions you may have when a loved one dies. It is not intended to answer "why" or "how," but rather, to let you know "what" death is, both legally and medically.


Defining death


Most people believe death occurs when a person's heartbeat and breathing stop. This is called "cardiac death." By law, the state of Missouri recognizes that death also occurs when the brain and brainstem stop working. This is called "brain death."

If breathing and heartbeat are maintained by machines, a brain dead person will appear to be alive. The person's skin may be warm: the chest will rise and fall in a breathing motion: a heartbeat is seen on a monitor. But, if there is no brain activity, the person is dead.

Cardiac death is simple to understand: the heart just stops. Brain death is harder. Certain things must happen before a person can be declared brain dead.


In adults and children over the age of one year

Heartbeat and breathing require ventilatory support. This means blood pressure, pulse and respiration are present only with artificial support.

Absence of all brain and brainstem function. The patient is comatose: there is no purposeful movement of response to any stimulus. Brainstem function is absent when

The pupils stay in midposition and do not react to light
The eye does not blink when touched
(corneal reflex)

The eyes do not rotate in the socket when the head is moved from side to side or up and down
(oculocephalic reflex)

The eyes do not move when ice water is placed in the ear canal
(oculo-vestibular reflex)

The patient does not cough or gag when a suction tube is placed deep into the breathing tube,

The patient does not breathe when taken off the ventilator
(Apnia test).


Confirmatory test


When the cause of death is unknown, or complicating medical conditions exist, confirmatory tests may be done. These could include either a blood flow study or an EEG.

In children under the age of one year

In determining brain death in children under the age of one year, it is necessary to repeat clinical examination after an appropriate observation period has passed. It is also necessary to perform a confirmatory EEG at each of the clinical examinations unless it is determined that there is no blood flow to the brain.

The following is a summation of observation periods and confirmatory tests in children:

Age 7 days to 2 months
Two examinations and two EEG's 48 hours apart
Age 2 months-1 year
Two examinations and two EEG's 24 hours apart.
Repeat examination and EEG are not necessary if it is determined that there is no cerebral blood flow. Cerebral blood flow studies to determine brain death include cerebral radionuclide angiography (CRAG) or a cerebral perfusion scan. A patient without blood flow through the brain does not have any brain function