The studies discussed thus far that included people reporting NDEs during cardiac arrest were retrospective in design. They involved questioning people about their experience and looking at their medical records some time after they actually happened. A much better research design would be prospective in which patients are under a physician’s care, their medical history is known, and exactly what goes on at the time of all medical interventions is documented. Neuropsychiatrist Peter Fenwick points out that the near-death experience studies involving patients who experience cardiac arrests are of particular interest because what happens to brain function is known, and the physiology which is active during the time of the experience can be inferred.
The signs of cardiac arrest are the same as clinical death. There is no cardiac output, no respiratory effort, and brain-stem reflexes are absent. Because the heart is no longer pumping blood to the brain, oxygen levels fall, blood pressure falls to zero, neural functioning is grossly disrupted, and the patient becomes unconscious. Loss of consciousness is rapid – as it is in fainting. Simultaneous recording of heart rate and brain electrical activity shows that within 11 seconds of the heart stopping the brain-waves go flat. You are, in fact, clinically dead. The international definition of death calls for – no respiration, no cardiac output, and absent brain-stem reflexes (you can’t cough or choke). This is the exact clinical state after a cardiac arrest. (Fenwick, 2008, p. 206)
Moreover, Fenwick points out, in spite of what we are led to believe from TV programs featuring emergency room heroics, most people experiencing cardiac arrest and receiving CPR are not successfully resuscitated. In fact, the average success rate is only between two and twenty percent. Most experience some residual brain damage, and the longer CPR is continued the more brain damage occurs. For those whose heart does start, blood pressure and circulation slowly return to normal. However, brain function doesn’t return to normal instantly, and during recovery those patients experience a confused mental state. (pp. 206 – 207)
The flat EEG indicating no brain activity during cardiac arrest and the high incidence of brain damage afterwards both point to the conclusion that the unconsciousness in cardiac arrest is total. Some skeptical materialists claim that in this state there is still brain activity, but in fact, the data are against this from both animal and human studies. The brain is not functioning during the arrest and does not begin to function again until the heart restarts. During this time every brain system that constructs our world for us is, in fact, down. The brain can’t create images, so it should be impossible to have clearly structured and lucid narrative experiences, and because memory is not functioning, if experiences did occur, they should not be remembered. So in theory it is impossible for anyone either to experience or to remember anything that occurred while they were in this state. And if an experience occurred during the gradual return to consciousness, it would be confused and not the clear lucid story which is characteristic of the temporary death experiences. (p. 207)
Fenwick and critical care physician Sam Parnia were the first in 2000 to carry out a prospective study with patients experiencing a cardiac arrest. Their subjects were the 63 people who survived out of 220 admitted to the coronary care unit at a British hospital. Not only did they know exactly what happened for these patients in cardiac arrest, but they knew that all had the same medications and were given the same resuscitation procedures. Furthermore, all patients could be interviewed as soon as they were well enough. The question posed by the investigators was, how many of them had a conscious experience and, if they did, was it similar to the traditional near-death experience. (p. 208)
Among the 63 cardiac arrest survivors involved, 89 per cent had no memories during their arrest, and about 10 per cent reported conscious experiences that were similar to those NDEs already reported in the literature. Patients reporting these experiences did not differ from those who did not in any of the following areas: medication, electrolytes, blood gases, religious belief or any other cultural factors. Furthermore, these patients who had NDEs said that the experiences occurred during unconsciousness. (p. 209) Neuroscience maintains that conscious experience is not possible during physical unconsciousness.
In 2001 a team of Dutch researchers headed by Pirn van Lommel published a large prospective study of NDEs in the highly respected international medical journal The Lancet. Their study involved 344 consecutive cardiac patients who were successfully resuscitated after cardiac arrest in ten Dutch hospitals. Comparisons were made of demographic, medical, pharmacological, and psychological data between patients who reported an NDE after resuscitation and patients who did not (controls). The patients experiencing cardiac arrest were clinically dead, which was defined by the authors as “a period of unconsciousness caused by insufficient blood supply to the brain because of inadequate blood circulation, breathing, or both.” In discussing the study van Lommel also stated that these patients had “a flat EEG, showing no electrical activity in the cortex and loss of brain stem function evidenced by fixed dilated pupils and the absence of the gag reflex.”
The patients were interviewed within a few days of resuscitation and asked whether they recollected the period of unconsciousness and what they recalled. Of the 344 patients interviewed, 62 or 18% reported elements of an NDE, and 41 or 12% reported a core NDE, as measured by the Ring scale. The incidence of NDEs among critically ill patients in this study was significantly less than that generally reported in other large studies. Ring had found 48%, Sabom 43%, and among children Morse found 67% experienced one. The study authors pointed out that patient age was most likely involved. The mean age of their NDEers was 62 whereas the mean age for Ring’s NDEers was 37 and Sabom 49. Younger people have a better chance of surviving cardiac arrest and thus to describe their experience.
Careful analysis of the data in this prospective study clearly indicated that the occurrence of patients NDE was not associated with duration of cardiac arrest or unconsciousness, medical factors, medication, or fear of death before cardiac arrest.
According to van Lommel,
Our results show that medical factors cannot account for the occurrence of NDE. All patients had a cardiac arrest, and were clinically dead with unconsciousness resulting from insufficient blood supply to the brain. In those circumstances, the EEG (a measure of brain electrical activity) becomes flat, and if CPR is not started within 5-10 minutes, irreparable damage is done to the brain and the patient will die. According to the theory that NDE is caused by anoxia [loss of oxygen to the brain], all patients in our study should have had an NDE, but only 18% reported having an NDE… There is also a theory that NDE is caused psychologically, by the fear of death. But only a very small percentage of our patients said they had been afraid seconds before their cardiac arrest—it happened too suddenly for them to realize what was occurring. More patients than the frightened ones reported NDEs. Finally, differences in drug treatments during resuscitation did not correlate with the likelihood of patients experiencing NDEs, nor with the depth of their NDEs. (van Lommel, 2001)
Two year after the initial interviews the researchers conducted a follow-up involving 35 of the surviving patients with an NDE (19 of the 62 had died). Their reported experiences since recovery were compared with those of a matched control group of 39 survivors without an NDE. These same patients still living eight years later (23 NDEers and 15 controls) were again followed-up. Both groups reported having gone through positive changes including being more self-assured, socially aware, and religious than before. Compared with the controls the NDEers experienced a much more complex coping process becoming more emotionally vulnerable, empathic, and intuitive with a significant increase in belief in an afterlife and decrease in fear of death.
For these people, this process of change appeared to take several years to consolidate, thus being more clearly evident at the eight-year follow-up. One reason for this, the researchers believe, had to do with society’s negative response to NDE, which leads people to deny or suppress their experience for fear of rejection or ridicule. Only gradually and with difficulty do they accept and integrate the experience. What was “surprising” and an “unexpected finding,” according to the authors, was “the long-lasting transformational effects of an experience that lasts for only a few minutes of cardiac arrest.” (IANDS, Dutch NDE Study Attracts Worldwide Attention,)
Another large similar prospective study was reported in 2003 by Bruce Greyson who followed 1,595 patients admitted to a cardiac care unit with heart trouble. He also found an incidence of 10 percent NDEs among cardiac arrest survivors and, furthermore, that the more severe the illness the more likely the survivor was to report an NDE. (Fenwick, 2015)
However, as is the case with much of psychical research in general, when it comes to NDEs there are no hard and fast rules as to how the phenomena should behave. Although the work thus far considered suggests that the closer one’s encounter is with actual clinical death the more likely an NDE will occur, there have been numerous reports of mystical experiences, closely resembling NDEs in many respects, that have been experienced by people who were not close to death at the time. In fact, one-fourth of the 800 people who had submitted an account of their experience to the IANDS online NDE archives (through 2008) reported they were not close to death or clinically dead at the time, but instead were in emotionally intense situations, praying or meditating, sleeping, or in ordinary states of consciousness when this phenomenon occurred. http://www.iands.org/research/nde-research/nde-archives31.html
A particularly important question regarding NDEs reported during periods of clinical death is whether any of these involved veridical elements, that is, reports of observations made from an out-of-body position that could be verified by others. Several such accounts have been reported in the literature. One of the best known is the case of Pam Reynolds, described by Michael Sabom in his book” Light and Death” [described under separate heading].
In 2008 Sam Parnia and his team began a major study to investigate both what happens in the brain immediately following cardiac arrest and how this relates to the likelihood of successful resuscitation as well as possible NDE and out-of-body experiences at this time. They knew from prior research that large numbers of hospitals were needed because of low survival rates with, at best, 10 percent expected to have any memories (NDEs) and only 2 percent expected to have an out-of-body experience. They secured the cooperation of twenty-five hospitals and placed interesting eye-catching images on shelves just below the ceiling over a large number of patient beds. After four years involving 4000 cardiac arrests the researchers found that out-of-body experience was even rarer than they thought and seemed to occur in less than 1 percent of survivors. In fact, only two of the 4000 described out-of-body experiences, and those did not occur where images had been placed above the beds.