The researchers led by NYU Grossman School of Medicine, in cooperation with 25 mostly US and British hospitals reported that up to an hour after their heart had stopped, some of the patients revived by cardiopulmonary resuscitation (CPR) had clear memories afterward of experiencing death, and they had brain patterns while unconscious that are linked to memory and thought.
Despite receiving immediate treatment less than 10% of the 567 patients who received CPR in the hospital recovered sufficiently to be discharged. Some of the survivors of cardiac arrest, but not all, described lucid death experiences that had occurred while they were seemingly unconscious. 4 in 10 of those who survived recalled some degree of consciousness during CPR that was not able to be captured by standard measures.
However, in a subset of patients who received brain monitoring, close to 40% had brain activity that returned to normal or nearly normal from a flatline state at points up to an hour into CPR. An electroencephalogram (EEG) recording of brain activity with electrodes was able to capture spikes in the gamma, delta, theta, alpha, and beta waves which are associated with higher mental function.
Survivors have reported having heightened awareness and powerful lucid experiences over the years, including a perception of leaving their bodies, observing events without distress or pain, and an evaluation of their actions and relationships. This study found that these experiences were different from illusions, dreams, delusions, hallucinations, or CPR-induced consciousness, according to the researchers.
“Although doctors have long thought that the brain suffers permanent damage about 10 minutes after the heart stops supplying it with oxygen, our work found that the brain can show signs of electrical recovery long into ongoing CPR. 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,” said Senior study author Sam Parnia, MD, Ph.D., associate professor in the Department of Medicine at NYU Langone Health and director of critical care and resuscitation research at NYU Langone.
“These experiences provide a glimpse into a real, yet little understood dimension of human consciousness that becomes uncovered with death. The findings may also guide the design of new ways to restart the heart or prevent brain injuries and hold implications for transplantation,” adds Parnia.
The researchers hypothesize that the flatlined dying brain removes the natural inhibitory systems collectively known as disinhibitions, which may open access to new dimensions of reality, and opens the door to a systematic exploration of what happens when a person dies. However, they conclude that research to date has neither proved nor disproved the reality or meaning of patients’ experiences and claims of awareness in relation to death. Suggesting that recalled experience surrounding death merits further empirical investigation and they plan to conduct additional studies that more precisely define biomarkers of clinical consciousness and that monitor the long-term psychological effects of resuscitation after cardiac arrest.
