Even after the heart stops in the human brain, it is confirmed that several minutes are still "alive"
In general, a person is recognized as "dead" when the heart or brain activity ceases. However, in the latest study, it is said that the brain cells are still in active state for 3 to 5 minutes even after the heart stops and the blood flow to the brain ceases, and it should actually be said that "the activity of the brain stopped" It has become clear that there is a moment.
Terminal spreading depolarization and electrical silence in death of human cerebral cortex - Dreier - 2018 - Annals of Neurology - Wiley Online Library
Does a Dying Brain Mean Death? Some Cellular Changes May Be Reversible, New Evidence Shows
Human brain still active minutes after heart stops beating, new research finds | The Independent
I did this research in Berlin, GermanySharityIt is a research team by brain scientists at university hospital. This research team says that they do not wish to prolong survival treatment before they are aliveLiving Will, Who studied in detail the changes to the brain at the stage of the death of a person under the cooperation of nine subjects who were heavily damaged by the brain.
The research team attached an electrode to the subject's head and monitored changes in brain activity. Generally, when the heart stops and the blood flow stops, the supply of oxygen that is carried to the brain by blood is stopped. Because the brain consumes a lot of energy, it suffers from serious damage as soon as oxygen is deficient, but oxygen that is stored in the blood and brain remains for several minutes from cardiac arrest Therefore, it is said that the activity of the brain will still continue for a while.
Dr. Jens Dreier, Dr. Jens Dreier of the Berlin Heart Seizure Center, the first author of the article, told Newsweek 's interview, "Within three minutes (from cardiac arrest), the energy sources stored in the brain are exhausted" . And in that state, the function of the ion that generates the potential difference necessary to make the activity work in the cell of the brain weakens, gradually calm the electrical activity "spreading suppression" occurs. It seems that this stage can be regarded as the stage where the brain truly stopped functioning. According to Dreier, the collapse of the potential gradient by this ion means that the wave of large electrochemical energy is transmitted in the form of "heat", cerebral neocortex and other parts of the brain.
However, the state where this electrochemical energy is lost can also be "unwound" at a certain level. Mr. Jed Hartings, a member of the research team and a cranial neuroscientist at the University of Cincinnati Medical School, is in a state with electrochemical energy like the original like at least for a short time It is possible to return it.
However, there is still much to be learned about how much time is left for the brain placed in that state, and how long it can live for the brain It is said that it is being done. Hartings says "The chemical change that causes death begins with the loss of the potential difference," after losing the potential difference literally the countdown to the final stage will steadily proceed.
Interestingly, this change is not consistent with "EEG". When the activity of the brain ceases, the wave of the brain wave disappears and it is said that it came to the brain death, but in this research it is showing the contents to be overturned. Mr. Hartings says, "There is fundamental insight here." By knowing what kind of change will occur in the brain due to cardiac arrest, it will lead to a better procedure procedure for organ donation.
It is not always easy to actually check "When the brain died." "There has been no way to diagnose the death of the brain so far, and there is no way to ensure that the ability to arouse the brain has been lost," Hartings said.
Many of the procedural procedures for organ transplantation are set so that the donor's heart stops and the organ is removed only after 5 minutes have elapsed since blood pressure was lost. This is based on the understanding that after 5 minutes of death the brain function is completely lost. However, based on data from past animal experiments, Mr. Dreier noted that "the nerve cells are not yet dead after 5 minutes," he pointed out that this "5 minutes" break is not necessarily reliable I will.
Based on data from past animal experiments, Mr. Dreier states that the probability that the person will be resuscitated even if blood circulation is restarted 5 minutes after cardiac arrest is "very high". However, it is said that there are still many unclear points as to whether it can completely return to the state of the brain before cardiac arrest.