Roughly 4 in 10 patients who were revived by cardiopulmonary resuscitation (CPR) after cardiac arrest reported clear memories of experiencing death, according to a new study led by New York University School of Medicine researchers. And while they were unconscious, their brain patterns looked like those associated with thought and memory.
The study, published in the journal Resuscitation, said those patients had brain activity that looked normal or near-normal at times, even an hour into CPR. The brain activity was monitored using an electroencephalogram (EEG) during CPR.
The researchers wrote: “People with cardiac arrest experience recalled experiences of death, including a lucid purposeful review of their lives, which may be tracked for the first time using brain monitors.”
NYU Langone Health reported that “the patients had spikes in the gamma, delta, theta, alpha and beta waves associated with higher mental function.”
The finding calls into question the notion that the brain always suffers permanent damage about 10 minutes after the heart stops and the oxygen supply is thus cut off.
“Our work found that the brain can show signs of electrical recovery long into ongoing CPR,” senior study author Dr. Sam Parnia, associate professor in the Department of Medicine at NYU Langone Health, said in the news release. “This is the first large study to show that these recollections and brain wave changes may be signs of universal, shared elements of so-called near-death experiences.”
“There’s nothing more extreme than cardiac arrest because they’re literally teetering between life and death, they’re in a deep coma and they don’t respond to us physically at all,” Parnia told Sky News.
Study design
According to Johns Hopkins Medicine, in cardiac arrest, the heart suddenly stops beating. It’s an absolute medical crisis.
“Those suffering from a cardiac arrest die if not treated immediately,” according to Newsweek. “Out of around 350,000 resuscitation attempts outside hospitals every year, the approximate survival rate varied from 5 to 10 percent, according to CPR Select. There is a 20 percent chance of survival out of 750,000 attempts in hospitals every year.”
The study followed 567 men and women experiencing cardiac arrest in the hospital between May 2017 and March 2020 in the U.S. and the United Kingdom. Of those, 85 were monitored via EEG to measure their brain waves. Another 126 community survivors of cardiac arrest who said they had memories from their cardiac arrest were interviewed, as well.
Some reported “memories/perceptions suggestive of consciousness.”
Of those who survived and completed interviews, 39% reported memories or perceptions from cardiac arrest and 21% had a “transcendent experience.” The researchers noted there were no external signs the patients were conscious, such as moving or groaning. But they said their data supports research suggesting a patient can be conscious without clinical signs of it.
Finding meaning
According to the news release, the researchers theorize that the “flatlined, dying brain” loses its natural inhibition, which could open a gate to “new dimensions of reality,” like lucid recall of stored memories from one’s lifetime, “evaluated from the perspective of morality.”
That could account for the notion that one’s life flashes past as one is dying. The release said that “while no one knows the evolutionary purpose of this phenomenon, it ‘opens the door to a systematic exploration of what happens when a person dies.’”
The researchers note that brain activity and awareness have long been reported but are not well understood. They said this is the first study of its kind to look at consciousness and electrocortical biomarkers during CPR.