Before the invention of cardiopulmonary resuscitation (CPR) in 1960, if you had a heart attack, you were considered dead. Your heart stopped functioning, and medical knowledge and interventions at the time wouldn’t be able to help you.

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Now, this isn’t the case anymore. 

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While it might seem fairly straightforward to pronounce someone dead, it’s more complex. Our understanding of death has changed over time, and continues to do so. This development is significant in the field of cryonics, especially when it comes to declaring legal death. But what does it mean to be dead? And how is someone declared legally dead?

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Concept of ‘Death’

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Today, we know that death is not a singular event, but rather a process. There are currently 4 concepts that can be used to explain this:

• Clinical death
• Legal death
• Biological death
• Information Theoretical death

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Simply put, clinical death is when your heart stops functioning. Biological death is when cells in the body, notably in the brain and organs, begin to die due to a lack of oxygenated blood. The longer a patient is left in this state, the more damage is incurred throughout the body. Information theoretical death, a concept relevant in cryonics, is when a patient’s brain is so damaged that revivalization is impossible, regardless of how far future medical technology advances Any information such as personality, memories, and identity cannot be extrapolated from the brain after informational theoretical death.

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Now, where does that leave legal death?

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What is Legal Death?

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Legal death is recognizing that a person is no longer alive according to the laws of the land. A medical professional must declare it. How they determine a patient is dead depends on where in the world you are. Two common methods for determining this are circulatory arrest and brain death. 

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Circulatory Arrest

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This takes place when your heart stops beating. It’s also known as sudden cardiac arrest. As previously mentioned, when this happens, your body no longer receives oxygen necessary to function properly. However, it’s important to understand what makes a sudden cardiac arrest different from a heart attack. 

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A normal heart attack occurs when there is one or more blockages in your coronary arteries. Sudden cardiac arrest takes place when the heart’s electrical system either malfunctions or becomes irregular, it’s beating too fast, or the ventricles are beginning to quiver (also known as ventricular fibrillation). This results in your heart being unable to pump blood throughout your body which leads to circulatory arrest. When this happens, there is an absence of blood flow in the brain which results in a loss of function. If left untreated, this can lead to death. 

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CPR or a defibrillator are essential to resuscitating a patient and restore oxygenated blood flow to the body. The longer a patient is without oxygen, the more likely it is that they will incur brain damage that worsens as time passes. This can cause brain death.

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Brain Death

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Brain death is when there is permanent and (currently) irreversible loss of brain functions. This is different from patients who are in persistent vegetative states (PVS), or in a coma. For patients in PVS, their brain is severely damaged. They have no cerebral cortical functions, meaning that they are both unconscious and unaware of what is happening. However, their brains do exhibit, albeit irregular, sleep–wake cycles which show evidence of brainstem autonomic functions. Someone in PVS can react to certain stimuli, opening their eyes, moving limbs, even moving their head towards sounds. A patient who has succumbed to brain death can’t do any of these things. In summary, someone in PVS is still alive while someone who is brain dead isn’t. A brain dead patient has lost the functions necessary to sustain life.

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These two types of physiological death have been critical in shaping our understanding of the dying process. However, depending on where you live, there may be other concepts that medical professionals use to legally pronounce someone dead. Let’s take a look at the differences in death between two European countries. 

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Case 1: The United Kingdom

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In the UK, there is no statutory definition of death. However, according to the Academy of Medical Royal Colleges Code of Practice For the Diagnosis and Confirmation of Death [1], they define death as:

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“the irreversible loss of the capacity for consciousness, combined with irreversible loss of the capacity to breathe.” [1](p.11)

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This is based on either cardiorespiratory or brain death. So how does the UK define them?

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UK Definition of Cardiorespiratory Death

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For cardiorespiratory death, the Code of Practice states that it can be diagnosed when it is confirmed that there is irreversible cessation of neurological, cardiac, and respiratory activities. Medical practitioners must confirm that there has been irreversible damage to key areas in the brain-stem based on the length of time since circulation has ceased. 

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Because of this, according to the Code, there is currently no standardized criteria for confirming cardiorespiratory death. This means that confirming death can take place as soon as the heart stops beating, or when CPR is abandoned based on protocol. In some cases, medical professionals wait ten minutes or more after the onset of asystole (complete cessation of the heart) and apnoea (complete cessation of breathing) to declare legal death. 

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UK Definition of Brain Death

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The standards for determining brain death, however, are different. In the UK, it’s defined as the irreversible cessation of brain-stem function [1]. This can occur either through internal or external cranial events. So how does brain death in the UK differ from PVS? As opposed to someone in PVS, a person who is brain dead cannot continue to function, even with life-sustaining interventions such as respiratory support.

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Doctors will examine a patient to see if the following conditions for brain death are met[1]:

• An absence of brain-stem reflexes
• Pupils do not respond to changes in intensity of light
• No corneal reflex (blinking or eyelid reflex) or oculovestibular reflexes
• No motor responses
• No cough reflex to bronchial stimulation
• Failure to respond to hypercarbia or apnoea test (increased carbon dioxide in the bloodstream)

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If a patient meets all the criteria, based on a diagnosis made by two medical professionals, then they are declared legally dead. Once this has taken place, a medical certificate of cause of death (MCCD) must be filed in order for families of the deceased to register their loved one’s death.

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Hopefully, you now have a good understanding of how legal death is declared in the United Kingdom. Now, let’s see how different or similar it is compared to another European country, Germany.

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Case 2: Germany

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Signs of Death in Germany

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In Germany, when a doctor is determining if a patient has died, they must identify and document at least one sign of death in order to make a declaration. There are several signs that doctors examine a patient [2]:

• Livor mortis→ Blood pooling to the lowest point under gravity, discoloring the skin. If the person is lying on their back while this is occuring, blood will pool in their back, and signs of livor mortis will be apparent through ‘dead spots’. These become fixed in place the longer a patient is dead.
• Rigor mortis→ Stiffening of the body due to a lack of ATP. This occurs between 6-12 hours after death. Doctors will examine two large joints in the body to determine if this has taken place
• Bodily destruction incompatible with life→ This is used if there is evidence of external damage to the body (a car accident for example).
• Brain death→ This is determined based on the criteria of the  Bundesärztekammer (BÄK/German Medical Association) which is outlined further below
• Autolysis→ The self-destruction of tissues and cells in the body. This begins within the abdominal region and spreads throughout the body, leading to liquefaction of the tissue. The body is decaying.
• Animal feed→ Evidence of fly eggs and maggot growth.

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Germany requires doctors to look for more signs of death than many other European countries. For example, unlike countries such as the UK, Austria, Switzerland, and the Netherlands, cardiac arrest alone is not enough to determine death in Germany. [3]. 

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Declaring Brain Death in Germany

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According to the Bundesärztekammer (BÄK/German Medical Association), brain death is defined as:

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“a state of irreversible cessation of the total function of the cerebrum (upper brain), the cerebellum (little brain) and the brain stem while the cardiovascular function is artificially maintained by controlled ventilation.” [4]

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In order for physicians to determine a patient has succumbed to brain death, a diagnosis must be carried out by two physicians. The diagnosis involves testing the reflexes in the brain-stem through clinical examination. This is because when a patient dies from brain death, brain-stem reflexes are gone compared to a patient who is unconscious. These reflex tests include [4]:

• Pupillary reflex
• Oculocephalic reflex (also known as Doll’s eye reflex)
• Corneal reflex
• Pain reflex
• Gag and cough reflex

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If a patient has failed all the reflex tests, the respiratory system has collapsed. When this happens, the brain must be monitored at a minimum period between 12-72 hours in order to determine the irreversibility of the brain damage [3]. 

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Once this is carried out, brain death can be declared. In cryonics, the fast response of the standby teams aims to minimize brain damage and successive death. For this reason, we must start the procedure as soon as possible after death to ensure quality brain preservation. However, we must always wait until after legal death has been pronounced.

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Conclusion

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Our changing understanding of death and developments in medical technology has impacted how medical professionals determine legal death in patients. Whereas in the past, cardiac death was the standard, new criteria such as brain death, livores mortis, and others have added to our knowledge of what makes someone dead. As we have demonstrated, even two countries in the same continent have different standards and criteria for determining this. Whether legal death is determined based on cardiac arrest or brain death criteria, only once it is declared can a standby team (SST) carry out human cryopreservation. 

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If you have any questions as to Tomorrow Bio’s cryopreservation procedures, schedule a call with us. We’ll happily answer any questions you may have. On Tomorrow Insight, we also have articles that discuss concepts like our SST, our preservation procedures, and all things related to cryonics and biostasis.