This information explains brain stem death and the tests used to confirm the diagnosis. It aims to answer frequently asked questions.
We will do our best to support you, so please do not hesitate to ask us if you have any further questions.
Many people do not realise that we can confirm someone has died in two ways:
- When a person stops breathing and their heart has stopped beating. This causes their brain to be starved of oxygen and die.
- When their brain stem dies first, it causes their heart and their breathing to stop (unless they are on a ventilator). This is called brain stem death. If someone’s brain stem dies it cannot recover, which means the person has died.
What is the brain stem?
The brain stem is a small area at the base of the brain. It is responsible for maintaining life, as it makes us breathe and keeps us conscious.
What is brain stem death?
Brain stem death is when a person has permanently lost the potential for consciousness and the capacity to breathe. These are the two definitions of life. This can happen even when a ventilator is keeping oxygen circulating through the blood and the heart beating. When brain stem death has been confirmed it means that person has legally died.
When does brain stem death happen?
Brain stem death happens when the brain has been injured in some way. Examples of these causes are: a head injury, bleeding into or around the brain, a tumour, a drug overdose, poisoning, suffocation or drowning.
When someone’s brain is injured it becomes swollen. Because it is enclosed in the skull, it reaches a point where it cannot swell any more. This puts pressure on the brain stem. When this happens, blood and oxygen cannot reach the brain and it dies.
How do you know when someone is brain stem dead?
The person will be unresponsive, they will not feel pain nor be in any discomfort. When we suspect brain stem death we need to carry out a series of strict tests. These are done by two senior doctors and they will carry these tests out twice. They are conducted in the same way in all hospitals. Before we can carry out these tests we need to ensure that any sedative medication has worn off and that the patient’s blood results and temperature are in normal range. It can take time to ensure this has happened – hours to a couple of days.
Tests for brain stem death:
- No pupil reaction to light
- No blink reaction
- No response to pain
- No cough or gag reflex
- No natural eye movement
- No attempt to breathe when taken off the ventilator
Questions you may have:
Why is their heart still beating?
Their heart is still beating because the ventilator is putting oxygen into the lungs and this oxygen keeps the heart beating. Without the ventilator, there is no oxygen, which makes the heart stop.
Why do they feel warm?
Because their heart is still beating, blood is still pumping around the body, keeping it warm and pink.
Will they move?
Sometimes the primitive reflexes of the spinal cord can cause movement. These, while they can be distressing, are not related to brain function.