Consciousness Beyond Life: The Science of the Near-Death Experience (25 page)
Read Consciousness Beyond Life: The Science of the Near-Death Experience Online
Authors: Pim van Lommel
This difference is clearly visible in patients with a temporary or permanent loss of blood flow in part of the brain. If a blood vessel (artery) in the brain is blocked by a blood clot, part of the cerebral cortex will receive no more blood and therefore no more oxygen and glucose. The resulting loss of function of this part of the brain will cause one-sided paralysis of the body, partial blindness, or the loss of speech. If the blood clot dissolves within five to ten minutes, the loss of function is temporary and the paralysis and other symptoms will disappear. Such temporary dysfunction is known as a transient ischemic attack (TIA). However, if the blood clot continues to block the blood vessel, the neurons die, leading to permanent dysfunction of that part of the brain. Patients are left with permanent paralysis or other symptoms, and this is called a cerebral infarction. It is also known as a stroke or a cerebrovascular accident (CVA). The loss of brain function is no longer transient because the neurons have sustained permanent damage and die as a result of prolonged oxygen deprivation (anoxia).
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During a cardiac arrest the entire brain is deprived of oxygen, resulting in the loss of consciousness, reflexes, and respiration. This is known as clinical death. It is usually reversible—that is, temporary, if resuscitation is begun within five to ten minutes. But a long delay in resuscitation may result in the death of a great many brain cells and thus in brain death. Most patients will ultimately die. A study carried out at a coronary care unit showed that patients whose resuscitation was started within one minute had a 33 percent chance of survival compared to only 14 percent for those who were resuscitated more than a minute after the onset of unconsciousness.
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What Happens During Resuscitation?
During resuscitation, blood gases (oxygen and carbon dioxide) are sometimes measured to determine the severity of the oxygen deficiency in the blood. However, normal levels do not guarantee that enough blood, and thus enough oxygen, will reach the brain during resuscitation.
Research has shown that external heart massage cannot pump enough blood to the brain to restore brain function. Nobody has ever regained consciousness during external resuscitation of the heart. This always requires defibrillation (an electric shock). Once the cardiac rhythm is restored, blood pressure usually stabilizes. Blood pressure is typically expressed in millimeters of mercury (mmHg) because of the now obsolete manometers that used a column of mercury. Under normal circumstances, blood pressure is approximately 140 over 80mmHg, with an average blood pressure of 100mmHg.
During resuscitation, blood supply to the brain is less than 5 percent of its normal value, and during external heart massage the systolic pressure (the first number) usually reaches approximately 50mmHg, with an average of 20mmHg because of the low diastolic pressure (the second number). The maximum average blood pressure during proper resuscitation is 30 to 40mmHg, which is still far too low for the blood to deliver enough oxygen and glucose to the brain. Giving certain medications during resuscitation can increase blood pressure a little, but it will remain well below normal.
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Furthermore, in the absence of a normal blood supply, the brain cells are likely to swell (edema), which results in increased pressure in the brain and actually requires higher than normal blood pressure to supply the brain with well-oxygenated blood and to remove carbon dioxide. Within seconds, a cardiac arrest results in serious oxygen deficiency and a buildup of carbon dioxide in the brain. This situation cannot be remedied during the resuscitation procedure itself, but can be addressed only by reestablishing cardiac rhythm through defibrillation (an electric shock).
Proper resuscitation, with adequate heart massage and mouth-to-mouth respiration or respiration via a mask, produces a low flow of blood to the brain, which increases the chances of recovering brain function after the cardiac arrest has been treated. There have been some cases in which the electrical activity of the brain was measured (EEG) during a cardiac arrest, for example during surgery. Following the cardiac arrest (no blood flow), this EEG flatlined after an average of fifteen seconds and remained flat during resuscitation.
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The EEG does not recover until both heartbeat and blood pressure have been restored, and the more prolonged the cardiac arrest and resuscitation, the longer the EEG will remain flat (hours or days). In other words, after a complicated but successful resuscitation, the patient will remain in a coma longer. If no resuscitation is begun, the brain will usually be irreparably damaged within five to ten minutes and the patients will nearly always die.
Temporary and Permanent Brain Damage After a Cardiac Arrest
The ultimate severity of the brain damage depends on how long the brain was completely deprived of blood during the cardiac arrest and on how long it received minimal blood supply during resuscitation with external heart massage and artificial respiration. The severity of the brain damage also depends on temperature. The lower the temperature, the later permanent brain damage occurs because a lower temperature reduces cell demand for oxygen and increases the chances of survival.
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Some people remain in a coma after a delayed resuscitation. A potential treatment for coma patients is hypothermia, which involves lowering the temperature of the head. A coma, both after a traffic accident (trauma) and after a delayed resuscitation, involves a cerebral edema, a swelling of the neurons, resulting in increased pressure in the brain. This means that despite normal blood pressure, blood supply to the brain decreases and patients remain in a coma for longer. The brain cells go into pilot-light state, otherwise known as hibernation of the brain.
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When the brain again receives a normal supply of well-oxygenated blood, brain function is sometimes restored. Therapeutic hypothermia reduces cerebral edema, thereby slightly improving blood supply and the survival chances of cells in the pilot-light state. The chances of waking from coma increase a little while the risk of brain death decreases a bit.
When animals go into hibernation, their body temperature plummets and their metabolic rate slows to a near halt. These animals can survive for months without food by putting their body in a kind of pilot-light state with barely perceptible breathing and pulse. The principle of hibernation is known not only in animals and the human brain; cardiologists have identified it also in the heart. A myocardial infarction leaves the heart scarred because heart muscle cells die and are replaced by scar tissue. However, examinations with ultrasound (echo) show that the loss of function of the cardiac muscle extends beyond the actual infarction. The peripheral areas around the infarction go into hibernation (pilot-light state) because the surrounding small blood vessels, the capillaries, maintain a low blood flow. Ultrasound or nuclear imaging can establish how likely it is that this tissue will functionally recover because it is still viable. If patients receive treatment such as bypass surgery or angioplasty (inserting a small balloon into a coronary artery), the hibernating part of the cardiac muscle will recover fully, even when this period of hibernation lasted several years.
There is evidence that tissue in pilot-light state can survive prolonged cell dysfunction. The same is true for the brains of coma patients with a flat EEG.
Pamela Reynolds’s NDE
Occasionally, a patient waking from a coma reports an exceptionally clear consciousness during his or her coma, including lucid thoughts and memories, emotions, a sense of identity, and verifiable perceptions from a position outside and above their unconscious body, despite the total absence of demonstrable brain activity. There are only a few known cases in which this loss of function has been carefully documented.
I therefore conclude this chapter with a comprehensive account of Pamela Reynolds’s NDE, as described by cardiologist Michael Sabom.
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Pamela also appeared at length in the BBC program
The Day I Died.
Because she had her NDE during brain surgery, when the activity of the cerebral cortex and brain stem were constantly monitored, hers is a good example of an NDE during carefully documented loss of brain function.
Pamela Reynolds was a thirty-five-year-old busy working mother who had carved out a name for herself as a singer-songwriter. In 1991 she became seriously ill. She experienced extreme dizziness, loss of speech, and difficulty in moving her body. Her physician recommended a CAT scan, which revealed a giant aneurysm in one of her cerebral arteries close to the brain stem. An aneurysm is a kind of balloonlike bulge at a weakened spot in a blood vessel, not unlike a bubble on the inside of a bicycle tire. If this aneurysm burst, and the risk of this happening was considerable, a cerebral hemorrhage would be immediately fatal. She was referred to a neurologist who told her that her chances of survival were minimal. But there was one last hope for Pamela. She contacted the Barrow Neurological Institute in Phoenix, Arizona, more than two thousand miles from her hometown.
Neurosurgeon Dr. Robert Spetzler at the Barrow Neurological Institute decided to operate on Pamela, even though her chances of survival were slight. Everything that happened during her operation was carefully recorded. During the operation her body temperature was lowered to approximately 50 degrees Fahrenheit. She was on a heart-lung machine because of the loss of all cardiac electrical activity (cardiac arrest), which always occurs during severe hypothermia. All the blood had been drained from her head. The electrical activity of her cerebral cortex (EEG) and of her brain stem (“evoked potentials” through 100-decibel clicks emitted by small molded speakers inserted into her ears) was under constant observation; in both cases, there was no activity whatsoever. During the interview in the BBC documentary, Spetzler explained:
What we’re looking at is the aneurysm that she had, which is at the very base of the brain. This is the balloon that can burst and cause this incredible catastrophe in the patient’s brain. This is why it was so difficult in this particular case…. What we want to do is we want to bring that brain to a halt. We don’t just want the brain to be asleep. We want the metabolic activity of the brain to stop. Every measurable output that the body puts out really disappears completely so that you have no measurable neuronal activity whatsoever.
Prior to the operation starting, a lot of activity goes on. The patient is put to sleep, the eyes are taped shut, and there are little clicking devices put in each ear in order to monitor the brain. The patient is then completely covered; the only thing that’s really exposed is the area of the head where we work.
And Sabom emphasizes:
During standstill, Pam’s brain was found dead by all three clinical tests—her electroencephalogram was silent, her brain-stem response was absent, and no blood flowed through her brain…. Her eyes were lubricated to prevent drying and then taped shut. Additionally, she was under deep general anesthesia.
Pamela’s account below is a composite of the written account of her experience in Sabom’s book and her interview in the BBC documentary:
I don’t remember an operating room. I don’t remember seeing Doctor Spetzler at all. I was with a fellow; one of his fellows was with me at that time. After that…nothing. Absolutely nothing. Until the sound…and the sound was…unpleasant. It was guttural. It was reminiscent of being in a dentist’s office. And I remember the top of my head tingling, and I just sort of popped out of the top of my head. The further out of my body I got, the more clear the tone became. I remember seeing several things in the operating room when I was looking down. I was the most aware that I’ve ever been in my entire life. And I was then looking down at my body, and I knew that it was my body. But I didn’t care. I thought the way they had my head shaved was very peculiar. I expected them to take all of the hair, but they didn’t.
I was metaphorically sitting on Dr. Spetzler’s shoulder. It wasn’t like normal vision. It was brighter and more focused and clearer than normal vision. There was so much in the operating room that I didn’t recognize, and so many people. I remember the instrument in his hand; it looked like the handle of my electric toothbrush. I had assumed that they were going to open the skull with a saw. I had heard the term
saw,
but what I saw looked a lot more like a drill than a saw. It even had little bits that were kept in this case that looked like the case that my father stored his socket wrenches in when I was a child. I saw the grip of the saw, but I didn’t see them use it on my head, but I think I heard it being used on something. It was humming at a relatively high pitch. I remember the heart-lung machine. I didn’t like the respirator…. I remember a lot of tools and instruments that I did not readily recognize. And I distinctly remember a female voice saying: “We have a problem. Her arteries are too small.” And then a male voice: “Try the other side.” It seemed to come from further down on the table. I do remember wondering what are they doing there [laughs] because this is brain surgery! What had happened was that they accessed the femoral arteries in order to drain the blood, and I didn’t understand that….I felt a “presence.” I sort of turned around to look at it. And that’s when I saw the very tiny pinpoint of light. And the light started to pull me, but not against my will. I was going of my own accord because I wanted to go. And there was a physical sensation to the point where…and I know how that must sound…nonetheless it’s true. There was a physical sensation, rather like going over a hill real fast. It was like
The Wizard of Oz
—being taken up in a tornado vortex, only you’re not spinning around. The feeling was like going up in an elevator real fast. It was like a tunnel, but it wasn’t a tunnel. And I went toward the light. The closer I got to the light, I began to discern different figures, different people, and I distinctly heard my grandmother calling me. She has a very distinct voice. But I didn’t hear her call me with my ears…. It was a clearer hearing than with my ears. And I immediately went to her. The light was incredibly bright, like sitting in the middle of a lightbulb. I noticed that as I began to discern different figures in the light—and they were all covered with light, they
were
light, and had light permeating all around them—they began to form shapes I could recognize and understand. And I saw many, many people I knew and many, many I didn’t know, but I knew that I was somehow and in some way connected to them. And it felt…great! Everyone I saw, looking back on it, fit perfectly into my understanding of what that person looked like at their best during their lives.I recognized a lot of people. And one of them was my grandmother. And I saw my uncle Gene, who passed away when he was only thirty-nine years old. He taught me a lot; he taught me to play my first guitar. So was my great-great-aunt Maggie. On Papa’s side of the family, my grandfather was there…. They were specifically taking care of me, looking after me.
They wouldn’t permit me to go further…. It was communicated to me—that’s the best way I know how to say it because they didn’t speak like I’m speaking—that if I went all the way into the light something would happen to me physically. They would be unable to put (this) me back into the body (me), like I had gone too far and they couldn’t reconnect. So they wouldn’t let me go anywhere or do anything.
I wanted to go into the light, but I also wanted to come back. I had children to be reared. It was like watching a movie on fast-forward on your VCR: You get the general idea, but the individual freeze-frames aren’t slow enough to get detail…. Sparkles is the image that I get. I asked if God was the light, and the answer was: “No, God is not the light, the light is what happens when God breathes.” And I distinctly remember thinking: I’m standing in the breath of God….
At some point in time I was reminded that it was time to go back. Of course I had made my decision to go back before I ever lay down on that table. But, you know, the more I was there, the better I liked it [laughs]. My grandmother didn’t take me back through the tunnel or even send me back or ask me to go. She just looked up at me. I expected to go with her. My uncle was the one who brought me back down to the body. But then I got to where the body was, and I looked at the thing, and I for sure didn’t want to get in it because it looked pretty much like what it was: void of life. I believe it was covered. It scared me, and I didn’t want to look at it. And I knew it would hurt, so I didn’t want to get in. But he kept reasoning with me. He says: “Like diving into a swimming pool, just jump in.” No. “What about the children?” You know what, the children will be fine [laughs]. And he goes: “Honey, you got to go.” No. He pushed me; he gave me a little help there. It’s taken a long time, but I think I’m ready to forgive him for that [laughs].
I saw the body jump…. And then he pushed me, and I felt it chill me inside. I returned to my body. It was like diving into a pool of ice water…. It hurt!
When I came back, and I was still under general anesthesia in the operating theater, they were playing “Hotel California,” and the line was “You can check out anytime you like, but you can never leave.” I mentioned [later] to Dr. Brown that that was incredibly insensitive, and he told me that I needed to sleep more [laughter]. When I regained consciousness, I was still on the respirator.
