What is Death?

Death has become a very medicalized thing. Especially recently, with the stories of Marlise Munoz and Jahi McMath hitting the news. Due to patient privacy laws, we can't know everything that happened in those cases, but they point out important lessons for the world as a whole.

Within the medical field, there are two criteria for 'declaring' death: cardiac death and brain death. Cardiac death is exactly what you would expect: someone dies because their heart stops beating. If they are resuscitated, we generally don't consider them to have died, but I want to point out that resuscitation (with CPR and ACLS) is rather unlikely. As this study shows, less than 5% of people who receive effective CPR in the community are 'brought back'. This may vary a bit in the hospital setting, because response times tend to be a little faster, but it's still not very effective.

Brain death, or death by neurological criteria, is fairly recent in origin; in the past, if you became dead by neurologic criteria (say you were decapitated), you would stop breathing and eventually your heart would stop. With the introduction of ventilators, we are now able to keep the heart pumping even though the person is dead. Let me repeat that: the person is dead. They do not become dead when the ventilator is removed; they are dead. This seems to be a common misperception in the lay population, especially in the media (where you'll see that individuals are being 'kept alive' with ventilators), so I want to clear it up now. Before we go any further, I want to define a few more terms.

A coma is a state of extended unconsciousness, in which a person does not respond to things in the environment. A lot of people will talk about a 'medically induced coma.' This simply means that the person is being sedated, similar to being put to sleep for surgery, so that their bodies can heal from whatever injury they had. Medically induced comas can be reversed by simply stopping the sedation medications. Spontaneous coma, usually caused by lack of oxygen to the brain, is potentially reversible—the longer you are in a coma, the less likely you are to return to your normal function. If the person in a coma does not regain consciousness within a period of time, usually a month, they are said to be in a persistent vegetative state (PVS). These people retain function of their brainstems, but do not have any higher brain activity—they do not think, interact with the world around them, etc. They are a body with reflexes.

In order to be considered brain dead (or dead by neurological criteria), you have to lose all brainstem function. The brainstem is the part of the brain that connects the brain to the rest of the body via the spinal cord. The things controlled here are things we don't need higher brain function for: breathing, controlling the speed of our heart, blinking, gagging, etc. The tests that must be run prior to diagnosing death by neurological criteria are: known cause of irreversible lack of brain function; cranial nerve function (pupils that do not move, lack of gag and blinking reflex, no withdrawal from painful stimuli); and inability to breathe spontaneously. This last test is done by turning off the ventilator for 10 minutes, and death is declared at the end of the 10 minutes.

If all these criteria are met, the person is dead. They have absolutely no hope of recovering. They are not in a coma, they are not in a vegetative state; they are dead. They are a shell of a body, if you will. Note, they will still have spinal cord reflexes, so if you bang on their knees, their legs might jerk, but those are not signs of brainstem function. Their heart is only beating because air is being pumping into their lungs and their heart muscle has not yet died. As such, these people are good candidates for organ transplant, because their organs are still getting oxygen because their hearts are still beating. Someone who died because their heart stopped is on a much shorter time scale, and many of the organs may not be functional long enough to be of use.

As a random aside, I recently watched a lecture in which the speaker was talking about the ineffectiveness of ACLS, which is used in the hospital setting when someone's heart stops. He made the point that failed treatment has the exact same outcome as no treatment at all... death. The person is still dead. The difference is, of course, hundreds of dollars of expensive medical treatment and the virtual destruction of the body in the process. Go gentle into that good night indeed. But for the most part, we are willing to pay this cost for the handful of people for whom this treatment is successful.

These are the medical ways that we define death, and most everyone accepts them. Different religions can have varying opinions of what death is. Some say it's when the soul leaves the body. Others say it's when a person stops breathing. All of these, of course, make it difficult to correlate medical death with 'death' according to these religions. That makes for some interesting issues surrounding the end of life. But that's a topic for another blog.

If you take nothing away from this blog, please, please, talk to your families about your wishes if you end up in an accident. It's really difficult to cover all the possible scenarios, but if you fill out an advanced directive before all this happens, then you can save your family a world of hurt trying to make these decisions for you. If you don't want to remain in a persistent vegetative state, you have the right to deny medical treatment in those circumstances (which may include ventilator support or feeding tubes), but the only way your family will know that that's what you want is if you tell them.