New evidence indicates patients recall death experiences after cardiac arrest
Elsevier
In a study led by researchers at NYU Grossman School of Medicine, in cooperation with 25 mostly US and British hospitals, some survivors of cardiac arrest described lucid death experiences that occurred while they were seemingly unconscious.
Despite immediate
treatment, fewer than 10% of the 567 patients studied, who received CPR in the
hospital, recovered sufficiently to be discharged. Four in 10 of patients who
survived, however, recalled some degree of consciousness during CPR not
captured by standard measures.
The study also found that in a subset of these patients, who received brain monitoring, nearly 40% had brain activity that returned to normal, or nearly normal, from a "flatline" state, at points even an hour into CPR.
As captured by EEG, a technology that records
brain activity with electrodes, the patients saw spikes in the gamma, delta,
theta, alpha, and beta waves associated with higher mental function.
Survivors have long reported having heightened awareness and powerful, lucid experiences, say the study authors. These have included a perception of separation from the body, observing events without pain or distress, and a meaningful evaluation of their actions and relationships.
This new work found these experiences of death to be different
from hallucinations, delusions, illusions, dreams, or CPR-induced
consciousness.
The study authors hypothesize that the "flatlined," dying brain removes natural inhibitory (braking) systems.
These processes, known collectively as disinhibition, may open access to "new dimensions of reality," they say, including lucid recall of all stored memories from early childhood to death, evaluated from the perspective of morality.
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."
Senior study author Sam Parnia, MD, PhD,
associate professor in the Department of Medicine at NYU Langone Health and
director of critical care and resuscitation research at NYU Langone, says,
"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."
Dr. Parnia adds, "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."
Called the AWAreness during REsuscitation (AWARE)-II study -- it followed 567 men and women who suffered cardiac arrest during hospital stays between May 2017 and March 2020 in the United States and United Kingdom. Only hospitalized patients were enrolled to standardize the CPR and resuscitation methods used, as well as recording methods for brain activity.
A subset of 85 patients received brain monitoring during CPR.
Additional testimony from 126 community survivors of cardiac arrest with
self-reported memories was also examined to provide greater understanding of
the themes related to the recalled experience of death.
The study authors 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.
They say the recalled experience surrounding death merits further empirical investigation and plan to conduct studies that more precisely define biomarkers of clinical consciousness and that monitor the long-term psychological effects of resuscitation after cardiac arrest.