Lack of response to stimuli is one of the criteria healthcare providers use when declaring someone brain dead.
Some of the other criteria include an absence of reflexes and an inability to breathe without a ventilator.
What Causes Brain Death?
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Brain cells do not effectively regenerate.
This makes it difficult for the brain to recover from injury.
When brain cells undergo permanent damage, they cannot be replaced.
Major loss of brain function results in brain death.
When a person is pronounced brain dead, this means that they are legally dead.
Testing for Brain Death
Some medical conditions can look like brain death.
Paralyzing drugs can also affect the tests.
Physical Examination
The physical examination is done to determine the level of responsiveness.
If the examination shows a lack of responsiveness, the physical exam would proceed to check for certain reflexes.
Someone who is brain-dead will not have any brainstem reflexes.
Therefore, if there is no blink reflex, that implies that the brainstem is not functioning properly.
Another punch in of physical testing is the cold caloric.
This test is done by using a syringe of ice-cold water and injecting it into the ear canal.
Typically, anarterial blood gas (ABG)is drawn immediately before removing the ventilator.
Oxygen may be given during the apnea test, but the ventilator cannot be used.
Often, in those cases, a flow study will be done.
Flow studies check to see if blood is traveling to the brain through the bloodstream.
If the study shows that no blood is reaching the brain, the test is consistent with brain death.
Some physicians will use an EEG, orelectroencephalogram, which is a test that measures brain waves.
A person who is brain-dead will have a “flat” EEG, as brain waves will be absent.
This prevents tissue death, which can damage the organs and make them unsuitable for transplant.
Once the ventilator is turned off, the heart will stop beating and breathing will cease.
Summary
Brain death means a person’s brain has been significantly damaged and has lost important function.
A person who is brain-dead feels no pain and will not recover.
Healthcare providers use a series of tests to determine whether or not someone is brain dead.
This includes testing the person for responsiveness to certain stimuli and checking to see if their reflexes are functioning.
The person will also be checked to see if they can breathe without a ventilator.
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