Implications of Near-Death Experiences for Emergency Medical Services

By Robert V. House, PhD

The only things in life that are certain are death and taxes. Whereas taxes are clearly certain, what happens in the proximity of death, and perhaps even how we define death, may be less so. From ancient times, humans who survived traumatic injuries (and more recently, those who are resuscitated from cardiac arrest or other life-threatening emergencies) have reported remarkably similar accounts of their perceptions and memories in extremis; these experiences are known as Near-Death Experiences(NDEs).

While NDEs have been mentioned since antiquity, the first known mention of them in a medical context did not occur until the 18th century.¹ The concept gained public exposure with the publication of the book Life After Life² that detailed more than 100 case studies of people who experienced “clinical death” and were subsequently revived. In the past, the medical profession tended to explain away and even reject these experiences rather than seeking to understand them on their own terms;^3,4 this has changed significantly in the intervening years and now NDEs are the subject of intensive study.

To comprehend NDEs we must also understand what it means to die. Death is an inevitable outcome for all living things and for humans and is never far from awareness, particularly for EMS providers whose occupation provides ample opportunities to reflect upon their own eventual demise.^5,6 In an era of ever-increasing sophistication of resuscitation technology, the concept of death has evolved.

Over most of medical history, cessation of the heartbeat served as the inflection point between life and death. However, with the advent of cardiopulmonary resuscitation, it is now possible to augment and – to a limited degree – replace the functions of the heart and lungs. Thus, we can delay the physiological processes that lead to tissue destruction and thus dissolution of the organism, the so-called “organism as a whole” concept of death.⁷

Although it is intuitive to believe that patients in cardiac arrest (who are traditionally and currently defined as dead) ***, approximately 20% of patients who have been resuscitated have some recollection of awareness of the resuscitation effort, referred to in the literature as “CPR-induced consciousness” or “CPR-induced awareness.”^8,9 Due to its rarity, recognition of this phenomenon by medical personnel remains ill-defined, although guidelines for its recognition have been proposed.¹⁰

The increasing number of reports of CPR-induced consciousness has led multiple researchers and clinicians to propose the consideration of analgesics and sedation during CPR,^11,12 although it is unclear how these protocols might work given the relative urgency of other resuscitative measures.

Increasingly, clinical death is being defined as irreversible cessation of all brain function, although there remains many uncertainties regarding specific criteria.^13,14 Brain death in tandem with cardiac arrest is now a definitive criterion of death, and this model has been standard medical practice in the US since the implementation of the Uniform Determination of Death Act of 1981.

The Act states that “An individual who has sustained either (1) irreversible cessation of circulatory and respiratory functions, or (2) irreversible cessation of all functions of the entire brain, including the brainstem, is dead. A determination of death must be made in accordance with accepted medical standards.” Since this was written, a better understanding of brain death has led physicians to lobby for revision of the Act, although such changes have not yet been enacted.¹⁵

Many NDEs include similar characteristic features including an out-of-body experience, experiencing movement through a tunnel, seeing or approaching a bright light, contacting otherworldly entities or dead family, having heightened senses, being suffused with a feeling of peace, and a comprehensive life review in which the entirety of the experiencer’s life seems to be replayed at a rapid speed (the so-called “life flashing before one’s eyes” which can also be experienced during the fear of death). Although many of these features are common, the sequence may vary.¹⁶

Another interesting aspect of NDEs is that the experience can be observed in individuals who are not technically “near death.” For example, Owens et al.¹⁷ reviewed the medical records of 58 patients, most of whom believed they were near death during an illness or after an injury and all of whom later remembered unusual experiences occurring at the time; of these, 28 patients were judged to have been so close to death that they would have died without medical intervention while the other 30 patients were not in danger of dying although most of them believe this was the case.

Patients of both groups reported similar experiences although patients who really were close to death were more likely than those who were not to report an enhanced perception of light and enhanced cognitive powers, which are hallmark features of NDEs.

This was confirmed in work by in a retrospective study by Charland-Verville et al.¹⁸ that showed that while “real NDEs” after coma of different etiologies were like NDE-like experiences occurring after non-life-threatening events, subjects reporting real NDEs tended to report a different content compared to the prospective experiencers.

Whereas most NDEs share characteristics of an uplifting and transformative experience, others have described various categories of unpleasant NDEs.^19,20 These include the Inverse NDE, the Void NDE and the Hellish NDE.

Inverse NDEsare those that begin much like pleasant NDEs but become unpleasant. In Void NDEsthe experiencers report sensations of experiencing a great void or emptiness along with feelings of emptiness. Finally, the rare Hellish NDEs are those in which the experiencer reports a descent into lower regions with fear and torture. Hellish ND experiences appear to be more common in attempted suicides¹⁹ and may lead to a form of PTSD.²¹

It may seem paradoxical that a phenomenon as personal as NDEs could be subject to quantification; however, Greyson²² developed the Near Death Experience Scale (generally known as the Greyson Scale). This scale is based on the self-reported replies to a series of 17 questions regarding the experience such as “Did you see or feel surrounded by a brilliant light?” and, “Did scenes from your past come back to you?” with each question having three possible answers.

Greyson concluded that this scale was “a reliable, valid and easily administered instrument for the quantification of a near death experience and its Cognitive, Affective, Paranormal, and Transcendental components.”

This concept was further enhanced into the Near-Death Experience Content (NDE-C) scale that included internal consistency, reliability, concurrent validity, and factor structure of the NDE experience.²³ In the NDE-C scale, features of the experience reflected experiences beyond the usual physical senses; the experience of harmony and/or belonging to a larger whole; experiencing moments/feelings of insight and/or of great understanding gained non-intuitively or non-rationally including visions of past and/or future events; the experience of leaving the earthly world and of coming close or entering a new dimension; and a gateway that might be accompanied by seeing a bright light at the end of this gateway.²³

A wide range of explanations of NDEs has been proposed, including birth memories, altered blood gases, REM intrusion, metabolic hallucinogens.²⁴ Other investigators have suggested that NDEs are simply hallucinations resulting from an altered state of consciousness.²⁵

Since NDEs are so similar among individuals of diverse cultures, some researchers suggest an underlying neurochemical mechanism of action. Accounts of the similarity between NDEs and certain drug-induced altered states of consciousness led Martial et al.²⁶ to perform a large-scale comparative analysis of these experiences between approximately 15,000 reports linked to the use of 165 psychoactive substances and 625 NDE narratives.

This analysis revealed that the N-methyl-D-aspartate (NMDA) receptor antagonist ketamine consistently resulted in reports most like those associated with NDEs. Ketamine was followed by Salvia divinorum (“magic mint”) and a series of serotonergic psychedelics, including the endogenous serotonin 2A receptor agonist N,N-dimethyltryptamine (DMT). DMT is an endogenous indolamine which produces brief yet fundamental shifts in the structure and content of consciousness in humans.²⁷

An interesting approach was taken by Sweeney et al.²⁸ who used an online survey to compare psychedelic-induced and non-drug experiences which altered individuals’ beliefs about death. Circumstances of the experience, mystical and near-death subjective features, changes in attitudes about death, and other persisting effects were evaluated.

Compared to the psychedelic groups, the non-drug group was more likely to report being unconscious, clinically dead and that their life was in imminent danger. The groups were similar in the reported changes in death attitudes attributed to the experience, including a reduced fear of death and high ratings of positive persisting effects and personal meaning, spiritual significance, and psychological insight, with non-drug participants being more likely to rate their experiences as the single most meaningful of their lives. To date, there is little convincing evidence that NDEs are solely the results of neurochemical reactions.

An early criticism of the NDE is that they are due to a religious – and more specifically theistic religions such as Christianity – worldview that includes belief in an afterlife, predisposing experiencers to validate their beliefs. While influence of religious belief on the NDE can be a contributing factor, multiple investigators have found that religious belief is not an absolute perquisite for either positive or negative NDEs,^29,30 and that individuals can experience NDEs in the absence of preexisting spiritual beliefs³¹ and in the context of certain forms of meditation that are known to produce a dissociative or out of body affect.³²

To recap, although an individual’s religious background may affect the content of their NDE, it appears that NDEs are not dependent on any religious belief. Two manuscripts that deal with this subject in a thoughtful manner were published by Nelson,³³ who acknowledged the metaphysical and spiritual aspects of NDEs while remaining firmly rooted in empiricism, and Alexander³⁴ who provided strong counterpoints to many of Nelson’s arguments.

Perhaps the most intriguing and productive avenue of investigation on NDEs has been to measure the activity of the brain itself during the process of dying. Using current technology, the only way to evaluate brain activity in unconscious patients – including those who are actively dying–is to use electroencephalograms (EEG). In one of the first such studies in humans Vicente and colleagues³⁵ performed continuous EEG recording from a dying human brain of an 87-year-old patient undergoing cardiac arrest after traumatic subdural hematoma.

Their findings were like previous studies in rats where an increase of low gamma band frequencies was observed 10–30 seconds after cardiac arrest. Further, the human data showed enhanced relative gamma power compared to other bands along with a decrease in theta waves. An interesting difference between animal and human studies was the observation of phase-amplitude coupling (cross-frequency coupling; in human brains, such modulation occurs in all gamma bands and is mostly mediated by alpha waves.

The alpha band is thought to critically interfere in cognitive processes by inhibiting networks that are irrelevant or disruptive. Given that cross-coupling between alpha and gamma activity is involved in cognitive processes and memory recall in healthy subjects,³⁶ it is possible to speculate that such activity could support the life review reported by NDE experiencers.

These results were expanded upon by Xu et al.³⁷ who analyzed the EEG of four dying patients before and after the clinical withdrawal of their ventilatory support. These researchers found that the resultant global hypoxia markedly stimulated gamma activities in two of the patients.

The surge of gamma connectivity was both local, within the temporo–parieto–occipital junctions, and global between these zones and the contralateral prefrontal areas, demonstrating that the dying brain can still be active and confirming that gamma activity appears to be an important aspect of this activity.

An important distinction emerges when evaluating EEGs in patients whose death proceeds unimpeded and those who are resuscitated. As described in the paradigm described by Charpier³⁸ using rat models, anoxia-dependent brain defects that lead to a process of potential death successively include:

1. a set of changes in EEG and neuronal activities,
2. a cessation of brain spontaneous electrical activity (isoelectric state),
3. a loss of consciousness whose timing in relation to EEG changes remains unclear,
4. an increase in brain resistivity, caused by neuronal swelling, concomitant with the occurrence of an EEG deviation reflecting the neuronal anoxic insult (the so-called “wave of death,” or “terminal spreading depolarization”) followed by,
5. a terminal isoelectric brain state leading to death.

However, a timely restoration of cerebral blood flow and thus oxygenation of the brain initiates a mirrored sequence of events consisting of a repolarization of neurons followed by a re-emergence of neuronal, synaptic, and EEG activities from the electrocerebral silence; this results in a death-related brain wave termed the “wave of resuscitation,” which is a marker of the collective recovery of electrical properties of neurons at the beginning of the brain’s reoxygenation phase.

Descriptions from near-death survivors may be our only avenue to fully understand what death looks like. Understanding the neurophysiological underpinnings of these descriptions in healthy subjects and correlating them with data obtained from the dying brain could be our only way to decipher the neurophysiology of death.³⁹

Finally, we must address the concept of consciousness itself, a topic of active discussion and debate among scientists and philosophers. From a materialist perspective, consciousness and awareness (terms often used synonymously) can be seen as the sum of physiological and neurochemical interactions in the living brain of humans and, to a lesser degree, other animals that show self-awareness.⁴⁰

However, decades of scientific research have yet to satisfactorily explain how brain function can produce what humans experience as subjective reality, a dilemma known to researchers as “the Hard Problem.”⁴¹ Efforts to reconcile the mind and the brain range from concepts such as resonance,⁴² human psychological biases,⁴³, neural patterns,⁴⁴ and even quantum entanglement.⁴⁵ Regardless, most researchers still attempt to craft an explanation rooted in physical reality as understood via the scientific method, however far-fetched some may appear.

The difficulty in resolving the question ultimately lies at the heart of understanding NDEs. If we cannot understand what is real vs what is only the result of a coordinated firing of neurons, the objective reality of NDEs remains an open question.⁴⁶

NDEs clearly are different in many ways from the daily experiences of most humans. However, there are intriguing similarities between NDEs and other forms of disconnected consciousness such as dreams, lucid dreams, hallucinations, coma, and general anesthesia.⁴⁷ However, for the millions of people who have recounted their NDEs, and the millions who never shared them, NDEs are as real as anything they have ever experienced.⁴⁸

NDEs are clearly a valid phenomenon warranting scientific study;⁴⁹ yet, aside from the academic and metaphysical aspects of NDEs, why should EMS personnel be interested in them? I propose the following:

1. There is evidence to suggest that some critically ill or moribund patients may be actively aware of the dying process that is distinct from the psychological awareness that death may be imminent, such as individuals in intensive care or hospice.⁵⁰ Rather, this is an active awareness of the process of death as it is occurring. For this reason, EMS personnel should be sensitive to the concerns of sick or injured patients who say they are dying or are about to die.
2. A growing body of data indicates that a certain percentage of cardiac resuscitation survivors remember the process, often in detail, even in the absence of a heartbeat and in the absence of certain kinds of brain activity indicative of consciousness. A smaller percentage of these patients report being conscious during the procedure. EMS personnel should be cognizant that patients in extremis may have either an immediate, ongoing awareness of their situation or at least may have memories of the event later. EMS personnel should be sensitive to comments made during resuscitation since these may be “recorded” by the patients’ memory.
3. Regardless of what NDEs truly represent, in nearly all cases the experience is clearly and positively transformative for the experiencer.⁵¹ While surviving a potentially fatal illness or injury would surely give most people a different perspective on life, those who experience an NDE experience a psychological and spiritual change in perspective so intense that the experience itself becomes a defining aspect of their personality.^52,53 Whereas most of the literature on NDEs is drawn from patients who are gravely ill, it is important to note that NDEs have also been reported by individuals surviving combat and other catastrophic events^54,55 and thus represent a larger patient population that might encounter EMS personnel. It is crucial that EMS personnel understand that NDEs are profoundly important to those who experience them and are integral to their overall psychological health. Rather than seeing patients in strictly naturalistic terms, NDEs represent an evolving paradigm for treating patients holistically.^56,57

About the Author

Dr. Robert V. House is a consultant to various biotech companies and has served as a bench scientist and scientific executive for a variety of research and development companies. He earned his PhD, MSPH, and BA degrees from the University of North Carolina at Chapel Hill. He is a recent National Registry Paramedic and is currently studying for Tactical Paramedic certification.

Editor’s Note: This commentary reflects the opinion of the author and does not necessarily reflect the opinions of JEMS.

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