Brain stem death is confirmed through a series of clinical tests that are performed by a healthcare provider. The tests are used to determine whether the brain stem, which is the lower part of the brain that controls functions such as breathing, heart rate, and blood pressure, is no longer functioning.
The first step in confirming brain stem death is to perform a thorough physical examination to rule out any reversible causes of coma, such as drug overdose or severe hypothermia (where body temperature drops below 28C). The healthcare provider will also check for signs of brain stem function, such as the ability to breathe on one’s own, the presence of a gag reflex, and the ability to move in response to stimuli.
If these tests are inconclusive or if the person has a condition that may affect the results, additional tests may be performed, such as an electroencephalogram (EEG) or a brainstem auditory evoked response (BAER) test. These tests can help to determine whether the brain stem is functioning and whether the person is in a vegetative state or has brain stem death.
Once all of the necessary tests have been performed and brain stem death has been confirmed, the healthcare provider will inform the person’s family and discuss any next steps, such as organ donation or end-of-life care.
Brain stem death vs. Vegetative state
There’s a difference between brain death and a vegetative state, which can occur after extensive brain damage.
Someone in a vegetative state can show signs of wakefulness – for example, they may open their eyes, but not respond to their surroundings. In rare cases, a person may show some sense of response that can be detected using a brain scan, but not be able to interact with their surroundings.
However, the important difference between brain death and a vegetative state is that someone in a vegetative state still has a functioning brain stem, which means that:
- some form of consciousness may exist
- breathing unaided is usually possible
- there’s a slim chance of recovery, because the brain stem’s core functions may be unaffected
Brain stem death, on the other hand, is a condition in which the brain stem is no longer functioning and the person is permanently unconscious and unable to breathe on their own. Brain stem death is considered to be the complete and irreversible loss of all brain function. A person who is brain dead has no chance of recovery, because their body is unable to survive without artificial support.