Near Death Experiences and the Medical Literature
Crislip, Mark, Skeptic (Altadena, CA)
Miracle Max: See, there's a big difference between mostly dead and all dead. Now, mostly dead: he's slightly alive. All dead, well, with all dead, there's usually only one thing that you can do.
Inigo: What's that?
Miracle Max: Go through his clothes and look for loose change.
--The Princess Bride
IN A RECENT ISSUE OF SKEPTIC (Vol. 13, No. 4), in the debate between Michael Shermer and Deepak Chopra about life after death, both authors refer to an article in the prestigious British medical journal Lancet about Near Death Experiences (NDEs). In this study of 344 cardiac patients who were resuscitated from clinical death, 12% reported near-death experiences, where they had an out-of-body experience and saw a light at the end of a tunnel. (Lommel, P.V., R.V. Wees, V. Meyers, I. Elfferich. 2001. "Near-Death Experience in Survivors of Cardiac Arrest: A Prospective Study in the Netherlands." Lancet. Vol 358 No. 9298: 2039.)
I read the article from the perspective of a physician who practices medicine in an acute care hospital who has seen many cardiac arrests over the years. The NDE question in the study hinges on whether the subjects were dead or nearly dead. In the article the authors "defined clinical death as a period of unconsciousness caused by insufficient blood supply to the brain because of inadequate blood circulation, breathing, or both. If, in this situation, CPR is not started within 5-10 min, irreparable damage is done to the brain and the patient will die."
Every patient in this study had CPR, most within 10 minutes of their cardiac arrest, so they all had blood delivered to their brain. That is the point of CPR. The authors write: "If purely physiological factors resulting from cerebral anoxia caused NDE, most of our patients should have had this experience." Yet, good CPR does not lead to cerebral anoxia. Most patients in this study did not have an NDE because they had CPR, so they had blood and oxygen delivered to the brain; thus, they could not have an anoxia mediated NDE.
So the real question is whether patients who had brain anoxia had an NDE, and there is no way to determine that in this paper. CPR by itself is not a good surrogate for cerebral anoxia. Having a cardiac arrest and being promptly coded does not mean there is insufficient blood and oxygen being supplied to the brain. CPR has variable efficacy, depending on the both the patient and the experience of the provider. Most of us who have had to be involved with an emergency respose to a cardiac arrest know, for example, the horrible sensation of all the ribs cracking when you start CPR on a frail old lady, knowing that the CPR is probably not going to be effective.
As a result of variable CPR, the time it takes the brain to become anoxic is also variable. And it is surprising how little oxygen people can tolerate with no discernible dysfunction in their cognition, although you might not want them flying your 747. People come into the hospital all the time with the amount of oxygen in their blood decreased by 30, 40, or even 50%, and yet they still walk and talk.
The point is that during a resuscitated cardiac arrest the ability of the brain to get oxygen can be quite variable, and if the CPR is done effectively the brain gets enough oxygen that it is not damaged. By the definitions presented in the Lancet paper, nobody experienced clinical death. No doctor would ever declare a patient in the middle of a code 99 dead, much less brain dead. Having your heart stop for 2 to 10 minutes and being promptly resuscitated doesn't make you "clinically dead". It only means your heart isn't beating and you may not be conscious. Declaring someone dead just because their heart isn't beating is not a good definition.
What about brain death? Here there are many criteria: the patient has to have no clinical evidence of brain function by physical examination, including no response to pain and a variety of nerve reflexes that do not work: cranial nerve, pupillary response (fixed pupils), oculocephalic reflex (steady gaze), corneal reflex (lack of reflexive blinking to stimulation), and no spontaneous respirations. …