How do we define death?

Defining brain death 

Before the ’60s, death was diagnosed after a doctor couldn’t find a pulse or heartbeat. The increasing use of ventilators, however, meant that unconscious patients were being kept alive. In the late ’60s, thoughts in the medical world turned to creating a clearer definition: death is when the brain stem is irreversibly destroyed. Here’s a look at the history of brain stem death, what brain death actually is and some of the current definitions of death.

The history of brain stem death 

The fact that death could be diagnosed in the brain emerged after the growing use of ventilators in the 60’s. Using ventilators meant that oxygen could still reach the heart, allowing it to continue to beat while that person was comatose. Those who were brain dead were then allowed to donate their organs; at that time, doctors had performed the world’s first pancreas, liver, lung, and heart transplants.

Then, Henry Beecher, a medical ethicist at Harvard and researcher into the placebo effect, suggested a ‘new’ death. Beecher contended that patients who were otherwise unconscious were being kept alive for no reason.

It was time, Beecher wrote to a colleague, “for a group at Harvard University to come to some subtle conclusion as to a new definition of death.” In 1967, irreversible destruction of the brain stem came to be called death. This kind of death was eventually adopted by the UK, Canada, Australia and most of Europe.

What is the brain stem?

The brain stem is the lower part of the brain that’s connected to the spinal cord (part of the central nervous system in the spinal column). It’s responsible for regulating most of the body’s functions that are essential for life. These include:

    • breathing
    • heartbeat
    • blood pressure
  • swallowing

The brain stem also passes information between the brain and the rest of the body. It plays a huge role in the brain’s core functions, such as consciousness, awareness and movement. After brain death, it’s not possible for someone to remain conscious.

How is brain death different to someone who’s in an unresponsive state?

In rare cases, after severe brain damage, a person might show some sense of response that can be detected using a brain scan, but not be able to interact with their surroundings.

The main difference between brain death and an unresponsive state due to severe brain damage is that the unresponsive person still has a working brain stem. This means:

    • some form of consciousness may exist
    • breathing unaided is usually possible
  • there’s a slim chance of recovery, as the brain stem’s core functions may be unaffected

chris-liveraniConfirming death

Confirming death now must take into account the wide-ranging, complex factors that go into keeping a ventilator turned on, if it’s used.

While it’s possible to keep the heart beating after the brain stem has permanently stopped functioning, that person won’t ever regain consciousness or start breathing again – there’s no way of reversing it and the heart will eventually stop beating, even if a ventilator continues to be used.

The decision here is rife with ethical questions, which are then compounded with the process of facing up to a loved one’s death.

What is death?

There are currently still many different approaches to death, even after decades of debating one, standardised definition. At the time of the new definition of death, complications around who was alive and who wasn’t surfaced: you could be declared dead in one US state and alive in another. This is still the case.

According to what’s known as the whole-brain standard, the current mainstream definition of death is defined as the irreversible cessation of functioning of the entire brain, including the brainstem. Simply put, death is when the brain stops.

For some, death depends on which parts of the brain have stopped functioning. For others, death should be seen as a process, which effects different functions and cells of the body at different rates of decay.

Find out more

If you’re fascinated by the ongoing case into brains and death, we’ve got more where that came from. Take a look at our article on the wandering history of Einstein’s brain, or take a look at how you can donate your brain after you die.

We’ve also got a Help and Support page.

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