A group of scientists, clinicians and engineers at the University of Pennsylvania Resuscitation Center is working to find ways to revive patients who have been in a state of clinical death for a long time
It all starts at the cellular level. According to associate professor of resuscitation, Dr. Honglin Zhou, it is possible to fairly accurately determine whether cells are alive or not, unlike the larger systems that make up them. Each cell has a tight outer membrane that serves to separate the contents from the environment and filter the molecules necessary for its existence. As a cell approaches death, its membrane weakens.
If the integrity of the membrane is violated, the cell dies. According to Dr. Zhou, when the permeability of the membrane reaches the point where the contents of the cell are released outside, its fate becomes a foregone conclusion. Science is now unable to unite dead cells. However, it turned out that some cells can remain alive for quite a long time, even despite a sharp loss of access to oxygen and nutrients.
The most susceptible to loss of nutrition are the brain cells - irreversible changes in the organ begin 5-10 minutes after the circulation stops. Moreover, the sudden supply of oxygen and nutrients to the cells, deprived of them for a long time, leads those to inevitable self-destruction.
The reasons for this are not fully understood, but scientists have found a way to extend the life of cells. In 1999, Swedish medical student Anna Bagenholm fell through the ice. For more than 40 minutes, friends tried to pull her out, and the girl's heart stopped. After another 40 minutes, doctors arrived at the scene, loaded the girl onto a helicopter and began resuscitation measures. Anna's heart began to beat again only 3 hours 55 minutes after stopping, and over time she almost completely recovered.
The researchers studied her case and came to the conclusion that, despite such a long time in a state of clinical death, biological death did not occur due to the low temperature (upon arrival at the hospital, her body temperature was only 13 degrees). Thus, by quickly lowering the patient's body to 33 degrees using a special intravenous solution, doctors have more time for resuscitation. It turned out that in this way it is possible to resuscitate patients whose heart has not been beating for several tens of minutes.
Doctors do not care whether this is considered to be the return to life of the dead or not, they care about the result. Dr. Zhou says he has spoken to people who have experienced relatively long clinical deaths. Although their brains survived, they have absolutely no memory of what they felt or experienced during cardiac arrest.