What is "death" and how is it determined in medicine?

Death is the disappearance of a person’s essential characteristics. It is a transition from life to death. Death is not the sudden end of life, but a continuous process of progress, a process from quantitative change to qualitative change of matter.

Sociology divides death into three periods: social death, intellectual death and biological death; medicine divides death into three periods: dying period, clinical death period and biological death period. The death referred to in medical ethics is equivalent to the biological death period of sociologists and the clinical death period of medicine.

The characteristics of the three stages of medical death are as follows:

1. The dying stage (dying stage)

It is the loss or deep depression of the nerve center function above the brainstem. , while the nerve function below the brainstem still exists, but is in a state of disorder due to the loss of control of the upper central nervous system. The patient showed confusion, circulatory failure, respiratory failure, metabolic disorder, various slow reflexes, and loss of muscle tone.

2. Clinical death stage

It is a state of deep depression and functional loss outside the brain, so various reflexes disappear and breathing and heartbeat stop.

3. Biological death period

It is the final stage in the death process. At this time, the metabolism of the entire nervous system and other organ systems, starting from the cerebral cortex, stops one after another. The entire body undergoes irreversible changes and cannot be revived. However, individual tissues can still have minimal metabolic activity for a certain period of time.

As for the standard of death, the medical community has always regarded respiratory and cardiac arrest as the only standard of death, and regards cardiopulmonary function as the most essential feature of life. Modern medical research shows that death is a continuous and progressive process. Since the 1940s, due to the widespread application of medical engineering technology, resuscitation techniques have been continuously improved, and people who have stopped heartbeating and breathing can still be resuscitated. Patients with extensive brain cell necrosis can still maintain their heartbeat and breathing for a long period of time due to the use of artificial ventilators; but once the ventilator is removed, breathing and heartbeat will stop immediately. The above shows that the cessation of cardiopulmonary function does not necessarily mean death, and the reliance on artificial maintenance of cardiopulmonary function does not mean that life continues to exist. This makes the traditional death standards face new challenges.

Since brain death is irreversible, some scholars have proposed loss of brain function as the criterion for death. The 22nd World Medical Congress held in 1968 proposed "irreversible loss of brain function" as the diagnostic criterion for death. Since then, the United States has also formulated the Harvard 4 criteria for brain death and the definition of death.

The "diagnostic criteria for brain death" are formulated from a medical perspective, thus replacing the traditional concept of death.

There are four criteria for brain death:

(1) The body does not respond to various stimuli;

(2) The body’s spontaneous movement and spontaneous breathing disappear;

(3) Various reflexes disappear;

( 4) Flat brain waves.

Brain death is irreversible. As a criterion for judgment, it is superior and more scientific than traditional standards, and has been accepted by more and more people. However, the traditional concept of death still has its influence. , so some people put forward the idea of ??integrating the two to make it more comprehensive and realistic, that is, the irreversible cessation of a person's circulatory and respiratory functions; or the irreversible cessation of all functions of the entire brain, including the brainstem, is death. .