Scientists were able to conduct for the first time the study of the features that accompany the death of the human brain at a time when this event is already irreversible. Observation of the phenomenon was carried out in several non-reanimation patients of one of the hospitals. The researchers shared their findings in the journal Annals of Neurology.
For many years, scientists are trying to find out in detail what happens to the human brain at the time of his death. Despite earlier discoveries in this field, progress in research in this area has somewhat stalled. First of all, because of the inability to control the very process of human death. One of the main duties of doctors is to avoid death as much as possible, therefore, experts are doing their best to this aspect, not to any monitoring there.
As a result, most of our knowledge of what actually happens to the brain during the transition from the living to the inanimate state is based only on the results of experiments on animals, as well as on the stories and observations of the reanimated patients who were actually on the verge of this irreversible event.
The poor, killed animals have made a significant contribution to understanding those states and processes that are accompanied by the death of the brain. Thanks to them, we learned that within 20-40 seconds after the onset of oxygen starvation, the brain enters the so-called “energy-saving regime” state, becoming electrically inactive. In this case, its neurons stop any communication between themselves.
A few minutes later, in the absence of oxygen, the brain begins to break down, as the process of splitting the ion gradients of its cells begins, and a wave of electrochemical energy called depolarization (or “brain tsunami”) spreads through the entire cortex and its parts, causing irreversible damage.
However, an international group of researchers led by a neurologist Jens Dreyer from the University of Charite in Berlin managed to make a real discovery. Scientists not only were able to observe for the first time the state of the brain at the time of cessation of its vital activity, but also found that the “brain tsunami”, that is the end point after which the brain finally dies, can be stopped. Such a conclusion they made on the basis of the study of nine non-reanimated patients with monstrous brain traumas.
“Soon after the blood supply stops, there is a spread of depolarization, indicating the release of accumulated electrochemical energy in the brain cells, after which toxic processes start to start, eventually leading to death,” explains Dreyer.
“It is important to add that this process is reversible, up to the point of recovery of blood circulation.”
Having resorted to neural monitoring technologies and using subdural electrodes, as well as intraparenchymal sensors, scientists came to the assumption that the spreading wave of depolarization does not represent the final process of brain death, as long as there is a possibility of restoring blood supply and oxygen supply.
“Anoxia (the absence of oxygen in the tissues) is completely reversible without any visible signs of cellular damage, if the oxygen level is restored to the so-called point of no return, when the process of neuronal death is triggered under the influence of permanent depolarization,” the authors explain in their work.
For patients at high risk of death or brain death due to ischemic or any other types of stroke, this discovery may one day become a lifesaver. Nevertheless, scientists explain that there is still a lot of work to be done so that doctors can use the methods of therapy developed on the basis of this discovery.
“To date, there is no direct way to use this discovery to save and treat patients,” Dreyer commented, adding that there is an obvious need for new research and observations in order to fully understand the issue.
“Understanding the processes involved in the spread of depolarization is of fundamental importance for the development of additional strategies and methods aimed at prolonging the survival of nerve cells in the event of a violation of perfusion (proper blood supply) of the brain.”