“Death is reversible.” So began NYU medical center’s director of Critical Care and Resuscitation Research Science, Sam Parnia, at a recent research consultation on people’s death experiences during and after cardiac resuscitation.
Biologically speaking, he explained, death and cardiac arrest are synonymous. When the heart stops, a person will stop breathing and, within 2 to 20 seconds, the brain will stop functioning. These are the criteria for declaring someone dead. When there’s no heartbeat, no breathing, and no discernible brain activity, the attending physician records the time of death.
Yet recent advances in science reveal that it may take many hours for individual brain cells to die. In a 2019 Nature report, slaughtered pigs’ brains, given a substitute blood infusion 4 hours after death, had brain function gradually restored over a 6-10 hour period. For many years now, brain cells from human cadaver biopsies have been used to grow brain cells up to 20 hours after death, explained Parnia. His underappreciated conclusion: “Brain cells die very, very slowly,” especially for those whose brains have been chilled, either medically or by drowning in cold water.
But what is death? A Newsweek cover showing a resuscitated heart attack victim proclaimed, “This man was dead. He isn’t any more.” Parnia thinks Newsweek got it right. The man didn’t have a “near death experience” (NDE). He had a death experience (DE).
Ah, but Merriam-Webster defines death as “a permanent cessation of all vital functions.” So, I asked Parnia, has a resuscitated person actually died? Yes, replied Parnia. Imagine two sisters simultaneously undergoing cardiac arrest, one while hiking in the Sahara Desert, the other in a hospital ER, where she was resuscitated. Because the second could be resuscitated, would we assume that the first, in the same minutes following the cessation of heart and brain function, was not dead?
Of 2.8 million CDC-reported deaths in the United States annually, Parnia cites estimates of possibly 1.1 million attempted U.S. cardiac resuscitations a year. How many benefit from such attempts? And of those who survive, how many have some memory of their death experiences (cognitive activity during cardiac arrest)?
For answers, Parnia offers his multi-site study of 2060 people who suffered cardiac arrests. In that group, 1730 (84 percent) died and 330 survived. Among the survivors, 60 percent later reported no recall of their death experience. The remaining 40 percent had some recollection, including 10 percent who had a meaningful “transformative” recall. If these estimates are roughly accurate, then some 18,000 Americans a year recall a death experience.
NDEs (or DEs) are reportedly recalled as a peaceful and pleasant sense of being pulled toward a light, often accompanied by an out-of-body experience with a time-compressed life review. After returning to life, patients report a diminished fear of death, a kinder spirit, and more benevolent values—a “transformational” experience that Parnia is planning to study with the support of 17 major university hospitals. In this study, cardiac-arrest survivors who do and don’t recall cognitive experiences will complete positive psychology measures of human flourishing.
One wonders (and Parnia does, too), when did the recalled death experiences occur? During the cardiac-arrest period of brain inactivity? During the moments before and at cardiac arrest? When the resuscitated patient was gradually re-emerging from a coma? Or even as a later constructed false memory?
Answers may come from a future Parnia study, focusing on aortic repair patients, some of whom experience a controlled condition that biologically approximates death, with no heartbeat and flat-lined brain activity. This version of aortic repair surgery puts a person under anesthesia, cools the body to 70 degrees, stops the heart, and drains the blood, creating a death-like state, during which the cardiac surgeon has 40 minutes to repair the aorta before warming the body and restarting the heart. Functionally, for that 40 or so minutes, the patient is dead . . . but then lives again. So, will some of these people whose brains have stopped functioning experience DEs? One study suggests that at least a few aortic repair patients, despite also being under anesthesia, do report a cognitive experience during their cardiac arrest.
Parnia hopes to take this research a step further, by exposing these “deep hypothermia” patients to stimuli during their clinical death. Afterwards he will ascertain whether any of them can report accurately on events occurring while they lacked a functioning brain. (Such has been claimed by people having transformative DEs.)
Given that a positive result would be truly mind blowing—it would challenge our understanding of the embodied person and the mind-brain connection—my colleagues and I encouraged Parnia to
- preregister his hypotheses and methods with the Open Science Framework.
- conduct the experiment as an “adversarial collaboration” with a neuroscientist who would expect a null result.
- have credible, independent researchers gather the data, as happens with clinical safety trials.
If this experiment happens, what do you predict: Will there be someone (anyone) who will accurately report on events occurring while their brain is dormant?
Sam Parnia thinks yes. I think not.
Parnia is persuaded by his accumulation of credible-seeming accounts of resuscitated patients recalling actual happenings during their brain-inactive time. He cites the case of one young Britisher who, after all efforts to restart his heart had failed and his body turned blue, was declared dead. When the attending physician later returned to the room, he noticed that the patient’s normal color was returning and discovered that his heart had somehow restarted. The next week, reported Parnia, the patient astoundingly recounted events from his death period. As Agatha Christie’s Miss Marple, reflected “It wasn’t what I expected. But facts are facts, and if one is proved to be wrong, one must just be humble about it and start again.”
My skepticism arises from three lines of research: the failure of parapsychology experiments to confirm out-of-body travel with remote viewing, the mountain of cognitive neuroscience evidence linking brain and mind, and scientific observations showing that brain oxygen deprivation and hallucinogenic drugs can cause similar mystical experiences (complete with the tunnel, beam of light, and life review).
Nevertheless, Parnia and I agree with Miss Marple: Sometimes reality surprises us (as mind-boggling DE reports have surprised him). So stay tuned. When the data speak, we will both listen.
(For David Myers’ other essays on psychological science and everyday life, visit TalkPsych.com.)
P.S. For those wanting more information: Parnia and other death researchers will present at a November 18th New York Academy of Sciences symposium on “What Happens When We Die?” (see here and here)--with a live stream link to come.
For those with religious interests: My colleagues, British cognitive neuroscientist Malcolm Jeeves and American developmental psychologist Thomas Ludwig, reflect on the brain-mind relationship in their recent book, Psychological Science and Christian Faith. If you think that biblical religion assumes a death-denying dualism (thanks to Plato’s immortal soul) prepare to be surprised.