Question: what happens when u die

Nina Rzechorzek answered on 4 Jun 2019:

Such an important question – and remains highly debated in the context of science, law, and culture. Others have nicely summarized the process of dying; ‘death’ is the defined end point in that process. The definition of ‘death’ varies by country, and amazingly, there is no clear definition of death written into UK law, although the diagnosis of death using neurological criteria (i.e. ‘brainstem death’) is generally accepted in England and Wales.
If you want to learn a bit more about brainstem death and how it is determined I strongly recommend reading Appendix 5 of ‘A Code of Practice for the Diagnosis and Confirmation of Death’ by the Academy of Medical Royal Colleges (revised 2008) which provides an excellent jargon-free summary. The whole thing is free to download here (feel free to bug me if you don’t understand anything in Appendix 5):
http://aomrc.org.uk/wp-content/uploads/2016/04/Code_Practice_Confirmation_Diagnosis_Death_1008-4.pdf

You may spot that the tests carried out by doctors to confirm death also require that certain ‘reversible’ causes of coma (loss of consciousness) have to be ruled out first. An important one is hypothermia (low body temperature) which has always fascinated me – basically, it is possible to be REALLY cold with no circulation and potentially be revived (I believe the coldest ever recorded temperature of a human that survived accidental hypothermia was 13.7 degrees Celsius – adding weight to the notion that ‘nobody is dead until they are warm and dead’). The report of this female skier was published in the medical journal ‘The Lancet’ in 2000, and describes how the resuscitation effort took place over 9 hours with gradual rewarming and amazingly, the patient made a full recovery. However, it’s important to note that many people have died of hypothermia at temperatures warmer than 13.7, so it’s better not to get stuck beneath a sheet of ice! In most patients we can easily get a good idea of what body temperature is doing, but brain temperature might be slightly different (and it’s much harder to measure), so we don’t know (in the case above) whether the brainstem, also reached 13.7 degrees. During hibernation, the brains of some animals reach near-freezing temperatures, and these animals recover naturally without any brain damage at all which is pretty amazing!

The other thing to note is that even when brainstem death has been confirmed, that does not mean that all of the cells in every organ suddenly die. Many cell types can survive for a short time without a blood supply (and much better if they are kept cold) – this is what makes organ donation possible. For similar reasons, it is possible to take small samples of e.g. skin from living human volunteers, transport them to the lab, and allow these skin cells to grow in the lab without a blood supply (as long as they are given enough nutrients and oxygen).

Death and dying always generates a lot of discussion, and whatever your beliefs, try to take part and have a voice in these discussions which are relevant to all of us, and will likely be high on the political agenda in the next few years.