Up to an hour after their heartbeat stopped, some patients revived by cardiopulmonary resuscitation (CPR) had clear memories of experiencing death and had brain patterns while unconscious related to thinking and memory, researchers report in the journal Resuscitation . .
AWAreness During Resuscitation - II: A Multicenter Study of Awareness and Awareness in Cardiac Arrest Cognitive activity and consciousness during cardiac arrest (CA) are reported but not well understood. This study, the first of its kind, examined consciousness and its underlying electrocortical biomarkers during cardiopulmonary resuscitation (CPR). Methods In a prospective study at 25 hospital sites, we incorporated: a) independent audiovisual testing of consciousness, including explicit and implicit learning using a computer and headphones, with b) continuous real-time electroencephalography (EEG) and cerebral oxygenation (rSO 2) monitoring of CPR during in-hospital CA (IHCA). Survivors underwent interviews to examine their consciousness memories and cognitive experiences. A complementary cross-sectional community study of awareness during cardiac arrest (CA) provided additional information about survivors’ experiences. Results Of 567 IHCAs, 53 (9.3%) survived, 28 of them (52.8%) completed interviews, and 11 (39.3%) reported memories/perceptions of CA that suggested awareness. Four categories of experiences emerged : 1) Coming out of coma during CPR (CPR-induced consciousness [CPRIC]) 2/28 (7.1%). 2) In the period after resuscitation 2/28 (7.1%). 3) Dream similar experiences 3/28 (10.7%). 4) Transcendent remembered experience of death (RED) 6/28 (21.4%). In the cross-sectional arm, 126 community survivors’ experiences of awareness during cardiac arrest (CA) reinforced these categories and identified another: delusions (misattribution of medical events). Low survival limited the ability to examine implicit learning. None identified the visual image, 1/28 (3.5%) identified the auditory stimulus. Despite marked cerebral ischemia (mean rSO 2 = 43%), normal EEG activity (delta, theta and alpha) compatible with consciousness appeared between 35 and 60 minutes after CPR. Conclusions Cognitive and consciousness processes may occur during consciousness during cardiac arrest (CA). The appearance of a normal EEG may reflect a resumption of cognitive activity at the network level and a biomarker of consciousness, lucidity, and RED (authentic “near-death” experiences ). |
Figure: Sankey diagram: visualization of emergence from coma in relation to CPR, in the period after resuscitation, dream experiences and remembered experience of death. Figure 3 These Sankey diagrams represent the flow of themes and categories for each type of experience. Each line represents individual analysis participants. Themes/categories are on the (left) and the individual participants (abbreviated as P followed by a number) on the right).
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In a study led by researchers at New York University Grossman School of Medicine, in cooperation with 25 mostly American and British hospitals, some cardiac arrest survivors described lucid dying experiences that occurred while they were apparently unconscious.
Despite immediate treatment, less than 10% of the 567 patients studied, who received CPR in the hospital, recovered enough to be discharged. However, four in 10 patients who survived recalled some degree of consciousness during CPR that was 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 close to normal, from a " flat" state , at points as late as an hour later. of CPR. As captured by EEG, a technology that records brain activity with electrodes, patients saw spikes in gamma, delta, theta, alpha and beta waves associated with higher mental function.
Survivors have long reported heightened awareness and powerful, lucid experiences, the study authors say. These have included a perception of separation from the body, observing events without pain or distress, and a meaningful evaluation of one’s actions and relationships. This new work found that these death experiences are different from hallucinations, delusions, illusions, dreams or consciousness induced by CPR.
The study authors hypothesize that the "flat" dying brain eliminates natural inhibitory (braking) systems. These processes, known collectively as disinhibition , can 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 . "
The study’s senior 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 brain suffers permanent damage in about 10 minutes After the heart stops supplying it with oxygen, our work found that the brain can show signs of electrical recovery for a long time after CPR. This is the first large study to show that these memories and changes in brain waves may be signs of universal and shared elements of so-called near-death experiences."
Dr. Parnia adds: "These experiences provide a glimpse into a real, if little-understood, dimension of human consciousness that is revealed by death. The findings may also guide the design of new ways to restart the heart or prevent brain injuries and have implications for health and transplantation."
The AWAreness During REsuscitation (AWARE)-II study followed 567 men and women who suffered cardiac arrest during hospital stays between May 2017 and March 2020 in the United States and the United Kingdom. Only hospitalized patients were enrolled to standardize the CPR and resuscitation methods used, as well as the methods of recording brain activity. A subset of 85 patients received brain monitoring during CPR. Additional testimonies from 126 community cardiac arrest survivors with self-reported memories were also examined to provide further insight into themes related to the remembered experience of death.
The study authors conclude that research to date has neither proven nor disproved the reality or meaning of patients’ experiences and claims of awareness in relation to death. They say the remembered experience around death deserves further empirical investigation and plan to conduct studies that more precisely define biomarkers of clinical awareness and monitor the long-term psychological effects of resuscitation after cardiac arrest.
