The tragic case of youngster Archie Battersbee, who sadly died last week, has no doubt caused discomfort and indeed distress, for the many who have followed it in the media.

While provoking debate, it may have also caused a certain degree of confusion of the meaning of some medical phrases, including the terms brain and brain stem death, as well the actual definition of death itself.

It may have also been portrayed that the doctors involved were against the parents, a feeling that no doctor or parent would ever wish to experience.

Brain death and brain stem death can be used interchangeably, but essentially mean the same thing.

The brain stem is located at the bottom of the brain. It is the control centre, linking the spinal cord to the cerebral hemispheres. These are the two halves of the brain that control our higher executive functioning. Put simply, these are involved in our emotions, decision making, personality and ability to form memories.

The brain stem is involved with controlling basic acts that we perform without thinking, such as breathing, heart rate, and swallowing. The brain stem is also responsible for our being conscious or awake.

Brain stem death has several causes. There may be an interruption to the blood supply due to a stroke or heart attack. Direct trauma to the brain, such as a head injury or tumour, may cause it to swell. This presses the brainstem downwards, forcing it through the base of the skull. This not only results in shearing of the structure but also interruption to the blood vessels supplying it. Brain stem death may also be caused by infection of the brain, such as encephalitis.

After a major trauma such as the above, a child or adult may be placed on a ventilator in an Intensive Care Unit. If they do not show signs of improvement, or display significant deterioration, the medical team involved will discuss with the next of kin about brain stem death testing.

In UK law, there are two definitions of death. The first is following cardiopulmonary arrest, that being where the heart and lungs cease to function. The second is if brain stem death is established.

The tests are highly sophisticated and are carried out by two senior doctors. They are repeated to avoid observer error. One of the clinicians will not be part of the team treating the patient. Neither are allowed to be part of the organ transplant team.

Any reversible cause of brain injury for example hypothermia or a chemical imbalance must be corrected before these tests are even considered.

In the event that the tests confirm brain death, this satisfies the legal definition of death. The team will then discuss disconnecting the ventilator with the next of kin. If appropriate, an organ transplant coordinator may approach the family, especially if the deceased has expressed their wishes to be an organ donor.

Brain death is irreversible, and despite any suggestions to the contrary, there are no treatments available.

The heart may beat for a short time after, which may cause confusion or alarm. However, the heart does not need the brain to keep beating so long as it has a supply of oxygen.

Movements of the arms or legs, including hand squeezing, again may make the observer feel that there is a degree of awareness. Sadly, these are only basic spinal reflexes.

It is important to differentiate brain stem death from persistent vegetative state (PVS). In PVS, despite significant injury to the brain, the brain stem remains intact. If disconnected from a ventilator, the patient should breathe spontaneously of their own accord. There may be some degree of awareness, although it may be severely limited. Theoretically there can be some improvement after PVS, yet it may be nowhere like the life the person had before.

On a final note, my sympathies, as I am sure those of anyone touched by this event, lie with the family of Archie Battersbee. The online challenge in which he was alleged to have taken part involved placing a noose round the neck with the aim of stopping breathing, albeit only temporarily.

I would implore anyone to never attempt these challenges, be that through any method of breath holding, or placing ligature round the neck. Unfortunately, this is not the first time a death has occurred as a result, but let us pray it may be the last.

Dr. Zak Uddin is a General Practitioner