A beating heart has been the prime indicator of the presence of life for thousands of years. A beating heart means life. Its absence means death. Modern medicine forces us to accept that this rule is both simplistic and wrong. A person can be dead while their heart continues to beat in their chest. On the other hand, a person can be very much alive even though their heart has stopped. A person can be alive even if they don’t currently have a heart. Like quantum physics, the modern medical concept of death is difficult to get your head around. But that’s not going to be a problem for you after you’ve read this post.

Death made simple

We all know what death is. Or at least we think we do. We don’t like saying the word out loud because it forces us to confront our own mortality. Notwithstanding our fears, death awaits us all, even if we often prefer to use Monty Pythonesque euphemisms for being dead when we absolutely must engage with the subject: stunned; deceased; pining for the fjords; demised; passed on; pushing up the daisies; history; kicked the bucket; shuffled off his mortal coil; run down the curtain; gone to meet his maker; joined the bleeding choir invisible; an ex-person; no more; ceased to be; expired; stiff; bereft of life; resting in peace.

One thing’s for sure: when you’re dead, you’re dead. End of. Except successful cardiopulmonary resuscitation, open-heart surgery, organ transplantation and the concept of brainstem death challenge our simple, intuitive, commonsense notion of what we think of as death.

If asked, most of us instinctively equate being alive with the presence of a heartbeat. Breathing is pretty important too, but the general consensus is that we will breathe until and unless our heart stops beating. For most people, the fact that an unresponsive person hasn’t breathed after a few minutes of careful observation is enough to convince them that person is indeed dead, regardless of whether they think they can feel a pulse or not. We don’t expect the being dead situation to change, either. People don’t spontaneously rise from the dead like a modern-day Lazarus. Death is a permanent state. Irreversible. There’s no going back from being dead.

Declaring somebody dead if their heart isn’t beating and they aren’t breathing works pretty well most of the time. Like Newtonian physics, it seems to describe the real world in which we live accurately. However, like Newtonian physics, our simplistic notions of death are wrong.

If you think about it, you already know that at least one of the attributes we associate with death is up for debate. That woman in the park last week, for instance, that you read about in the local paper, was undoubtedly dead when she was found deeply unconscious and unresponsive by a dog walker. She wasn’t breathing and had no pulse. The dog walker performed effective CPR, and when the paramedics arrived six minutes later, they diagnosed ventricular fibrillation and zapped the woman with their defibrillator. She woke up in hospital disorientated, agitated and confused, but these are behaviours associated with the undead, not the dead. We can reasonably conclude either that one of the fundamental tenets of death, of it being a permanent and irreversible state, is patently untrue, or that the woman was not dead in the first place.

Why a beating heart does not prove someone is necessarily alive

Most people, and I include doctors, even an intensivist such as me who diagnosed many patients as brainstem dead, find it challenging to get their heads around the idea that a person can be dead even though their heart is still beating. Rather like quantum theory, it doesn’t make intuitive sense. To get to grips with the concept, you need to do a bit of deep thinking.

Consider this. If you remove a healthy heart from a brainstem dead person’s body, provide it with oxygen and nutrients and it will continue beating for hours. Nobody would argue that the person the heart was removed from is still alive because their heart is beating. Nobody would argue that the beating heart is a person, either. A beating heart is evidence only that the heart, as an organ, is alive. Not the person. Transplant that same heart into another person and we do not transplant that heart’s owner into the recipient. The idea that the personality, the mind, the soul of the donor are transplanted along with their heart is patent nonsense.

Your heart is important.

As are your lungs.

Your kidneys are important, too.

But none of these organs is what makes you the person you are – a living, unique human being. That would be your brain. A heartbeat is evidence only that the heart is alive. It is not evidence that the person is alive.

What about someone who has been guillotined?

Was Marie Antoinette still alive and conscious, if only for a few seconds, immediately after her head was chopped off on the guillotine? Did she have time to think, ‘That didn’t hurt a bit,’ as her head rolled into the basket? Her heart would have continued to beat for several minutes afterwards. At what point did she die? I put it to you that most reasonable people would argue that Marie Antoinette ceased to exist as an independent, unique individual (died) pretty much straightaway because her brain, containing her essence, was permanently disconnected from its life support system when she was beheaded. What her heart might have been doing for the next few minutes would have been irrelevant.

Why not having a beating heart doesn’t mean that a person is necessarily dead

During open-heart surgery, cardiac surgeons intentionally stop the patient’s heart. A beating, mobile heart interferes with the delicate surgery they need to perform to bypass obstructed coronary arteries or to replace defective heart valves. A heart-lung bypass machine temporarily performs the functions of both the heart and the lungs during the several hours it takes for surgery to be undertaken. The patient does not have a beating heart. Nor are they breathing. The patient is unquestionably alive, though. No one would regard them as dead. The reason they are deemed to still be alive is that their brain, the repository of that person’s mind, personality, spirit, and soul, is alive. It just so happens that the person isn’t breathing and their heart has stopped for a while.

To take our thinking one step further, a patient who undergoes heart transplant surgery does not even have a heart during the period between their original, defective heart being removed and their new, transplanted heart being plumbed in. So now we can state that you can still be alive and not have a heart at all, whether it be beating or not.

A thought experiment

Would you be alive or dead if only your brain existed as a going concern, suspended in a vat of nutrient broth? You would have the capacity for thought and self-awareness. You might also be able to smell and see, although, being disconnected from a peripheral nervous system, you would be unable to taste, hear or touch your world. My question isn’t whether such a life would be worth living. It’s whether this state would constitute being alive. And before you answer no, how does this condition equate to being dead, the only other alternative?

It’s the brain, stupid

Whether we are alive or dead depends on what our brain is doing, or is capable of doing.

Arguing the toss about what Marie Antoinette might or might not have been thinking immediately after her head separated from the rest of her body might be fun for the university debating society, but declaring a person to be dead even though their heart is still beating is not an academic question. Without the concept of brainstem death, countless patients with no hope whatsoever of ever waking up again would be kept ‘alive’ on a ventilator to no purpose. Their loved ones would be given false hope, their agony of suffering needlessly prolonged. It would also mean denying the precious resource of an ICU bed to someone else with a realistic prospect of recovery from their critical illness. And without brainstem death, countless people with intractable heart failure, severe lung disease, kidney failure and liver failure would be denied the opportunity of receiving donated organs and instead be condemned to lives of misery and suffering before their premature deaths.

The brainstem versus the brain

Our brain is a relatively large organ occupying the entirety of the inside of our skulls. It weighs about three pounds (1.4 Kg) and receives fully 20% of the total cardiac output pumped through the circulation by the heart, regardless of how brainy or stupid we are, or whether we’re concentrating fiercely on some problem or other versus daydreaming about spending the day with Kylie Minogue (other fantasy idols are available). Our consciousness resides within our brain. Our personality. Our sense of who we are. The very essence of who we are.

The brainstem is a projection from the base of the brain comprising the midbrain, pons and medulla oblongata, that acts as a neural control centre, regulating all manner of vital functions. It’s relatively tiny, weighing in at only an ounce (25-30g). For such a small amount of tissue, it’s incredible what the brainstem does. To have any chance of understanding why we are dead if our brainstem is dead, we need to have some knowledge of what functions our brainstem performs.

The next four paragraphs are for the nerds among you and contain a somewhat detailed description of what your brainstem does, day in, day out. For those of you with a less than nerdy disposition, feel free to jump ahead. You won’t miss anything essential.

What has my brainstem ever done for me?

The brainstem serves as the neural connection between higher cerebral centres (cerebral cortex, thalamus, hypothalamus, amygdala and hippocampus), where we think, feel, emote, remember things, and so on, and the spinal cord below. Apart from this key role as a neural relay station, the brainstem also contains numerous neurophysiological control centres.

The brainstem regulates and controls the heart and circulatory system. Hunger, thirst, the body’s temperature control thermostat, and a myriad other control centres are all here, too. Although all these different regulatory and control centres within the brainstem are vital for life, two particular areas are of paramount importance: the Reticular Activating System (RAS) and the respiratory centre.

The RAS, a dense network of nerve cells located within the brainstem, is responsible for determining whether we are awake, conscious and self-aware on the one hand, or asleep and unconscious on the other. It determines whether we are connected to the real world or disconnected from it. The RAS isn’t itself the seat of consciousness. Rather, it is a switch that tells higher cerebral centres to wake up when it is set to the ‘On’ position. If the RAS fails, rather like a traditional petrol-engined car without a starter motor, the brain is going nowhere.

The other neural centre within the brainstem of supreme importance is the respiratory centre. Breathing is regulated by collections of neurones that function as an automatic pacemaker without which we would all stop breathing and die as soon as we fell asleep. If the respiratory centre is damaged beyond repair, an individual can never breathe for themselves.

Most of the cranial nerves arise from the brainstem, the exceptions being the olfactory nerves (sensitive to smell) and the optic nerves (sensitive to light), which can almost be viewed as outward projections of the brain. As we shall learn in a later post, testing the function of these brainstem cranial nerves, as well as testing whether an individual in apparent deep, unresponsive coma can breathe for themselves, forms the basis of making the diagnosis of brainstem death.

As a related aside, sufferers of a rare medical condition called Ondine’s curse have a malfunctioning respiratory pacemaker. Individuals affected have no automatic drive to breathe. Not a problem while they’re awake. They can simply remind themselves to keep breathing. The situation becomes slightly trickier when they fall asleep, though. Voluntary control of breathing is lost, and there is no autopilot to take over. Such individuals simply stop breathing. Sufferers of Ondine’s curse generally require a permanent tracheostomy and mechanical ventilation while they sleep.

This final bonus paragraph is for the űber-Nerds only. Ondine was a mythological water spirit in European folklore. These elemental spirits could only gain a human soul by marrying a mortal man. Ondine married a knight named Lawrence. When she discovered he had been unfaithful, she cursed him so that he must forever will himself to breathe. If he ever fell asleep, he would die. For days Lawrence fought a gruelling battle to stay awake. Eventually, sheer exhaustion overcame him, he fell asleep and died. Lawrence was a dead man walking, perhaps the first documented case of someone with a beating heart being dead already.

Ah! The non-nerds have rejoined us. Welcome back.

The brainstem contains our drive to breathe. It coordinates essential reflexes. It integrates the body’s responses into a single functioning whole. Although the brainstem is not the seat of consciousness, it contains the switch to turn our consciousness on and off. The loss of brainstem function means the switch is permanently set to the off position and therefore the capacity for consciousness is lost.

To reiterate: when a person’s brainstem is damaged beyond repair, there is zero possibility of that individual ever regaining consciousness. They will never breathe for themselves. They will never again be the person they once were. Which is why, in the UK and other countries throughout the world, the death of a person can be diagnosed if there is irreversible loss of brainstem function, regardless of what their heart might be doing.

Brainstem death takes our understanding of death to a whole new level, though. Its diagnosis is not a prediction that someone will die soon. It is not a statement that recovery is incredibly unlikely. Neither is it a description of a deep, unresponsive coma that a person might possibly wake up from one day, however unlikely. It means the person is dead. Even though their heart may continue beating. Even though a mechanical ventilator may push air in and out of their lungs.

What causes brainstem death?

You already knew (or thought you knew) before reading this post that a person dies when their heart stops beating – well, it is true at least 99.9% of the time. Or when they stop breathing – also true 99.9% of the time. Everybody knows that. It’s commonsense and accords well with how we observe the world operating around us. Hopefully, you now appreciate that the reason why someone dies when they stop breathing, and their heart stops beating, is because the death of the brain as a whole, including the all-important brainstem, inevitably follows after a period of only a few minutes without it receiving its regular oxygen and nutrient supply. But perhaps you’re still sitting on the fence about this brainstem death lark. You want to know more. In particular, you want to know what might cause someone’s brainstem to peg it when their heart is quite happy to bat on.

The demographics of brainstem death are different from regular cardiopulmonary deaths. The victim is more often relatively young and fit before disaster strikes out of the blue. A massive subarachnoid brain haemorrhage resulting from a ruptured cerebral artery aneurysm, for instance, causes a massive rush of blood into the closed confines of the rigid, bony skull. Intracranial pressure spikes precipitously, cutting off the blood supply to the brain and causing further injury from oxygen starvation. The brainstem is forced downward through the opening at the base of the skull where the brainstem joins with the spinal cord, crushing all the vital neural control centres housed within it.

Other major insults to the brain cause a similar outcome – a severe head injury, meningitis and encephalitis, lack of oxygen to the brain (in contrast to a lack of oxygen to the body as a whole) caused by strangulation or beheading.

Although the brainstem may die first, the rest of the brain soon follows suit from the adverse effects of elevated intracranial pressure. If you performed an EEG on such a person,  it would show a flatline. Zero electrical activity within the brain. A sort of cerebral asystole. The concept that you may be dead if your brain is dead is less difficult to accept if you have ever attended a post-mortem examination where the deceased was diagnosed brainstem dead and watched as the pathologist literally poured the liquefied, necrotic brain out of the top of the skull into a metal dish. This liquefaction occurred before the victim’s heart stopped beating, not after the fact.

The doctors only say you’re brain dead so that they can nab your organs!

The inevitable question arising when we pronounce a person with a beating heart, mechanically ventilated lungs and functioning liver and kidneys dead is how we can be sure they won’t recover. Absolutely, 100% sure, that there isn’t even a one in a million chance they might recover. Even if recovery only meant existing in a minimally-responsive coma for the rest of their life, it would prove that a person diagnosed as brainstem dead hadn’t ever been dead in the first place.

It’s also important to state that the ICU medical team looking after a potential organ donor and the surgical organ transplant team are strictly separate. There is no direct conflict of interest.

What happens if you don’t turn off the ventilator after brainstem death has occurred?

The most important thing is what doesn’t happen. There has never been a single documented case of an adult fulfilling the necessary preconditions for assessment and satisfying all of the criteria for brainstem death subsequently regaining consciousness. It really is an everyone dies scenario.

I can already hear the shouts of protest from the back: But only last week I read in the paper/saw in my social media feed/heard on the radio/ watched on the TV news that someone diagnosed as brain dead miraculously woke up.

These are sensationalised media headlines representing irresponsible reporting. In every single case that has been properly investigated, the reality was that the patient was never actually brain dead in the first place.

This is what always happens if you keep a brainstem dead patient on a mechanical ventilator and continue to actively manage them:

1.      Their blood pressure progressively drops despite heavy doses of powerful stimulants.

2.      Their heart fails.

3.      Their body temperature drops as physiological systems wind down.

4.      Their hormones stop being secreted.

5.      Their brain rots.

Even with aggressive medical intervention, the body of a brainstem dead individual cannot be sustained. Over a period ranging from a few days to a few weeks, the various bodily functions deteriorate and break down, regardless of how many drugs, fluids and artificial hormones are administered. Cardiac asystole inevitably supervenes.

Conclusion

There are two definitions of death. One definition, the commonsense notion, is that you die when there is an irreversible cessation of your circulation. Your heart has thrown in the towel, and nothing is going to make it start up again. You stop breathing as a result. The second definition, which you may have considered for the first time while reading this post, is that you also die when there is an irreversible cessation of your brainstem function following catastrophic damage to it.

Thinking about it, if your heart isn’t beating and you’re not breathing, catastrophic, irreversible damage to your brainstem follows naturally. It is this that makes you dead, not the absence of a beating heart per se.

A final word

Phew! That was hard going. The gluttons for punishment among you will be wondering why I haven’t said anything about clinical brainstem death tests and organ donation. Worry not. I haven’t forgotten. Both subjects will be coming up in a future post.

Check out my website at https://www.drtonymccluskey.com for more details about my books and how you can read free chapters.

My three books, Vocation, Resuscitation, and Resignation, are available to purchase as eBooks or paperbacks at https://www.amazon.com/dp/B0DJ3273KH.

(https://www.amazon.co.uk/dp/B0DJ3273KH for readers in the UK).