An inadvertent consequence of advances in stem cell research, neuroscience, and resuscitation science has been to enable scientific insights regarding what happens to the human brain in relation to death. The scientific exploration of death is in large part possible due to the recognition that brain cells are more resilient to the effects of anoxia than assumed. Hence, brain cells become irreversibly damaged and "die" over hours to days postmortem. Resuscitation science has enabled life to be restored to millions of people after their hearts had stopped. These survivors have described a unique set of recollections in relation to death that appear universal. We review the literature, with a focus on death, the recalled experiences in relation to cardiac arrest, post-intensive care syndrome, and related phenomena that provide insights into potential mechanisms, ethical implications, and methodologic considerations for systematic investigation. We also identify issues and controversies related to the study of consciousness and the recalled experience of cardiac arrest and death in subjects who have been in a coma, with a view to standardize and facilitate future research. Keywords: death; cardiac arrest; resuscitation; death by brain death criteria; near-death experiences (NDEs); out-ofbody experiences (OBEs); external visual awareness (EVA); recalled experience of death (RED) coma; cardiopulmonary resuscitation-induced consciousness (CPRIC); post-intensive care syndrome (PICS)
Background:
Few studies have examined the psychological outcomes of cardiac arrest (CA) survivors. While some negative outcomes including post-traumatic disorder, anxiety and depression have been reported in ~50%, interestingly, ~10-20% of CA survivors have reported lucid, well-structured thought processes during CA associated with positive psychological outcomes and transformation post CA. We aimed to characterize the themes describing the cognitive experiences recalled by survivors.
Method:
In a qualitative study 118 self-reported cases were extracted from a CA survivor registry, coded the data using thematic analysis to identify emerging themes followed by descriptive statistics to identify frequencies of identified themes.
Results:
Analysis of 69 in-hospital and 45 out-of-hospital CA events led to identification of 10 major and 64 sub-themes describing the breadth of CA survivors’ cognitive experiences. Most predominate features included having no sense of pain during on-going CPR (18%), perception of being separate from the body (46%), observing the body from a point outside (40%), travelling through a tunnel towards a destination (16%) and having a life review (19%). Interestingly, in the life-review category 87% perceived the life-review to be an educational experience focused on their actions and intentions towards others, 38% described reliving of certain actions with a sense of shame, and 18% perceived to examine life events from others’ perspective. In addition, another category of cognitive experiences were also described that appeared to relate to events during recovery of consciousness around the time of return of spontaneous circulation (ROSC) where 14% of survivors sensed the pressure of CPR and 18% woke up with pain.
Conclusion:
CA survivor’s memories appear to reflect two categories: 1) a life review and perception of observing themselves during CPR without pain, which is felt to be educational, positive and peaceful and 2) memories related to the recovery phase around the time of ROSC. These include sensing CPR related events such as pain, chest pressure and distress. While the former category may explain the long-term positive transformation, the latter may explain the long-term occurrence of PTSD and anxiety in CA survivors.
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