As you may know, I have an interest in the topic of near death experiences (NDEs). 

I believe there is now enough evidence in the scientific literature as well as enough quality first-person accounts to suggest some form of veridical experience occurs in the first few minutes of cardiac arrest (we cannot know further out than this because, well….dead).

Perhaps this is just the last-gasp mental activity of a dying brain. Perhaps.

I believe these experiences support the view of a growing number of scientists and philosophers (and of course, spiritual contemplatives) that consciousness is non-local (that it is located somewhere outside the brain), and that it survives in some form after death of the ‘material’ body.

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Here is a recently published scoping review that looks at the common characteristics of Near Death Experience (NDE) during cardiac arrest.

Near-death experiences are unusual phenomena that may occur at times of mortal peril. These experiences may include profound feelings of transcendence. Those who have had a near-death experience have been described to, at times, have longstanding and pervasive changes in outlook and behaviour. Despite decades of research and scientific discourse on the subject, the frequency, causes, and consequences of near-death experiences remain incompletely understood.

A total of 60 records published in various countries were examined (from which 20 full-text studies were retrieved). Some of the commonalities found included:

• NDE’s may occur in as many as one third of patients who have a cardiac arrest.
• NDE’s are not limited to the event of cardiac arrest.
• Many of the studies examined use descriptive tools that may not accurately express the ctual language of the experiencer.
• Data is often confounded as NDE particulars often occur in the setting of other experiences such as delirium, confusion, conventional dreams, and drugs given in the resuscitation or ICU setting.
• Some characteristics demonstrated an increased propensity for NDE. These included: being under the age of 60, first myocardial infarction, previous NDE, type of arrhythmia during cardiac arrest (eg those with pulseless electrical activity had significantly more NDEs than those with ventricular fibrillation).
• Common experiences shared across all the papers studied included: Alterations in time perception, a feeling of peace or pleasantness, heightened (more vivid) experience, and a feeling of separation from the body.
• Positive changes on a life-change questionnaire that remained at an 8-year follow up. It was noted that psychological changes following cardiac arrest may also be due to some drugs, particularly Ketamine which may have a long lasting anti-depressant action.
• Potential increased risk of 30-day mortality compared to people who did not have NDE.

The authors of the paper also warn that “It is important to note that the studies investigating factors associated with near-death experiences were insufficiently powered to reliably derive conclusions, with multiple methodological issues and potential sources of bias present. It is also noteworthy that multiple studies, of the few studies included, were conducted by the same investigators.”

Despite this, they pragmatically urge for future research into the phenomenon, both as a tool to explore consciousness and as a guide to improve mental and physical models of care in this cohort.

Full article: Near-death experiences after cardiac arrest: a scoping review.