A cat's eye is a sign of biological death. Death as a biological phenomenon

Clinical death is a reversible stage of dying. In this state, with external signs of death of the body (absence of heart contractions, spontaneous breathing and any neuro-reflex reactions to external influences), the potential possibility of restoring its vital functions using resuscitation methods remains.

Diagnosis of clinical death is based on a triad of signs: lack of consciousness (coma), breathing (determined by the method of catching a stream of air in the ear), pulse in the large arteries (carotid and femoral). To diagnose clinical death, there is no need to resort to instrumental studies (ECG, EEG, auscultation of the heart and lungs).

Biological death occurs after clinical death and is characterized by the fact that against the background of ischemic damage, irreversible changes in organs and systems occur. Its diagnosis is carried out on the basis of the presence of signs of clinical death, followed by the addition of early and then late signs of biological death. Early signs of biological death include drying and clouding of the cornea and the “cat's eye” symptom (to detect this symptom, you need to squeeze the eyeball; the symptom is considered positive if the pupil is deformed and elongated). Late signs of biological death include cadaver spots and rigor mortis.

« Brain (social) death “- this diagnosis appeared in medicine with the development of resuscitation. Sometimes in the practice of resuscitation doctors there are cases when, during resuscitation measures, it is possible to restore the activity of the cardiovascular system (CVS) in patients who were in a state of clinical death for more than 5-6 minutes, but in these patients irreversible changes have already occurred in the cerebral cortex. The respiratory function in these situations can only be supported by mechanical ventilation. All functional and objective research methods confirm brain death. In essence, the patient becomes a “cardiopulmonary” drug. The so-called “persistent vegetative state” develops (Zilber A.P., 1995, 1998), in which the patient can remain in the intensive care unit for a long time (several years) and exist only at the level of vegetative functions.

Signs of biological death

Lack of consciousness.

No heartbeat.

Lack of breathing.

Clouding and drying of the cornea. The pupils are wide and do not react to light (maybe a cat's pupil due to softening of the eyeball).

Cadaveric spots appear on the underlying areas of the body (2 hours after the onset of clinical death)

Rigor mortis (hardening of muscle tissue) is determined 6 hours after the onset of clinical death.

Decrease in body temperature (to ambient temperature).

41. Basic methods of cardiopulmonary resuscitation.

Stages of resuscitation:

WITH. Ensuring the movement of blood through the vessels - indirect cardiac massage. Hand presses are frequent and short. The point of application of the hands is the place of attachment of the 5th left rib to the sternum (2 transverse fingers above the xiphoid process). During pressing, the chest should approach the spine by 4-5 cm. It is carried out for 5 minutes; if it is ineffective, defibrillation is started (this is already stage D). 100 compressions per minute (30 compressions 2 breaths).

A.(air of open) - to open air access - correct positioning of the patient, for men the trouser belt is unfastened, for women - everything that interferes with breathing (belts, bras, etc.) is torn off. foreign bodies are removed from the mouth. Laying the patient in the Safar position: the head is thrown back, the mouth is opened slightly, the lower jaw is extended. – this ensures airway patency.

B. artificial ventilation of the lungs - 5 artificial breaths are given to the patient (if there is an obstruction in the larynx, a tracheostomy is performed).

D. Mechanical defibrillation - precordial fist blow. Chemical defibrillation is the administration of medications that stimulate the heart. Electrical defibrillation is the action of an electric defibrillator.

Chemicals are injected only into a vein - atropine, adrenaline, calcium preparations.

Electrical defibrillation is carried out with a short pulse discharge through the axis of the heart. They start with 3.5 thousand volts, the next discharge is increased by 500 volts and brought to 6 thousand volts (i.e., 6 discharges are obtained: 3.5 thousand V, 4 thousand V, 4.5 thousand V, 5 thousand V, 5.5 thousand V, 6 thousand V ). After novocaine is administered intravenously to reduce arrhythmia, stage C and D are carried out again. Stages C and D are repeated 5-6 times.

Following clinical death comes biological death, characterized by a complete stop of all physiological functions and processes in tissues and cells. With the improvement of medical technology, the death of man is moving further and further. However, today biological death is an irreversible condition.

Signs of a Dying Person

Clinical and biological (true) death are two stages of one process. Biological death is declared if resuscitation measures during clinical death were unable to “start” the body.

Signs of clinical death

The main sign of clinical cardiac arrest is the absence of pulsation in the carotid artery, indicating cessation of blood circulation.

Absence of breathing is checked by movement of the chest or by placing the ear to the chest, as well as by bringing a dying mirror or glass to the mouth.

Lack of reaction to a sharp sound and painful stimuli is a sign of loss of consciousness or a state of clinical death.

If at least one of the listed symptoms is present, resuscitation measures should begin immediately. Timely resuscitation can bring a person back to life. If resuscitation was not carried out or was not effective, the last stage of dying occurs - biological death.

Definition of biological death

The death of an organism is determined by a combination of early and late signs.

Signs of a person’s biological death appear after the onset of clinical death, but not immediately, but after some time. It is generally accepted that biological death occurs at the moment of cessation of brain activity, approximately 5-15 minutes after clinical death.

Accurate signs of biological death are the readings of medical devices that record the cessation of electrical signals from the cerebral cortex.

Stages of human dying

Biological death is preceded by the following stages:

Preagonal state - characterized by sharply depressed or absent consciousness. The skin is pale, blood pressure can drop to zero, the pulse can be felt only in the carotid and femoral arteries. Increasing oxygen starvation quickly worsens the patient's condition.
Terminal pause is a borderline state between dying and life. Without timely resuscitation, biological death is inevitable, since the body cannot cope with this condition on its own.
Agony - the last moments of life. The brain stops controlling vital processes.

All three stages may be absent if the body was affected by powerful destructive processes (sudden death). The duration of the agonal and preagonal periods can vary from several days and weeks to several minutes.

The agony ends with clinical death, which is characterized by the complete cessation of all life processes. It is from this moment that a person can be considered dead. But irreversible changes in the body have not yet occurred, therefore, during the first 6-8 minutes after the onset of clinical death, active resuscitation measures are carried out to help bring the person back to life.

The last stage of dying is considered irreversible biological death. Determination of the occurrence of true death occurs if all measures to remove a person from a state of clinical death have not led to results.

Differences in biological death

Biological death is distinguished between natural (physiological), premature (pathological) and violent.

Natural biological death occurs in old age, as a result of the natural decline of all body functions.

Premature death is caused by a serious illness or damage to vital organs, and can sometimes be instantaneous.

Violent death occurs as a result of murder, suicide, or is a consequence of an accident.

Criteria for biological death

The main criteria for biological death are determined by the following criteria:

Traditional signs of cessation of vital activity are cardiac and respiratory arrest, absence of pulse and reaction to external stimuli and strong odors (ammonia).
Based on brain death - an irreversible process of cessation of vital activity of the brain and its stem sections.

Biological death is a combination of the fact of cessation of brain activity with traditional criteria for determining death.

Signs of biological death

Biological death is the final stage of human dying, replacing the clinical stage. Cells and tissues do not die simultaneously after death; the lifespan of each organ depends on the ability to survive complete oxygen starvation.

The first to die is the central nervous system - the spinal cord and brain, this happens approximately 5-6 minutes after true death occurs. The death of other organs can last for several hours or even days, depending on the circumstances of the death and the conditions of the deceased body. Some tissues, such as hair and nails, retain the ability to grow for a long time.

Diagnosis of death consists of guiding and reliable signs.

Orienting signs include a motionless body position with absence of breathing, pulse and heartbeat.

A reliable sign of biological death includes the presence of cadaveric spots and rigor mortis.

There are also differences between early and late symptoms of biological death.

Early signs

Early symptoms of biological death appear within an hour of death and include the following signs:

Lack of reaction of the pupils to light stimulation or pressure.
The appearance of Larche spots - triangles of dried skin.
The appearance of the "cat's eye" symptom - when the eye is compressed on both sides, the pupil takes on an elongated shape and becomes similar to the pupil of a cat. The "cat's eye" symptom means the absence of intraocular pressure, which is directly related to arterial pressure.
Drying of the eye cornea - the iris loses its original color, as if becoming covered with a white film, and the pupil becomes cloudy.
Drying of the lips - the lips become dense and wrinkled, and acquire a brown color.

Early signs of biological death indicate that resuscitation measures are already pointless.

Late signs

Late signs of human biological death appear within 24 hours from the moment of death.

The appearance of cadaveric spots occurs approximately 1.5-3 hours after diagnosing true death. The spots are located in the underlying parts of the body and have a marble color.
Rigor mortis is a reliable sign of biological death, occurring as a result of biochemical processes occurring in the body. Rigor mortis reaches full development in about a day, then it weakens and after about three days disappears completely.
Cadaveric cooling - it is possible to state the complete onset of biological death if the body temperature has dropped to air temperature. The rate at which the body cools depends on the ambient temperature, but on average the decrease is approximately 1°C per hour.

Brain death

The diagnosis of “brain death” is made when there is complete necrosis of brain cells.

The diagnosis of cessation of brain activity is made on the basis of the obtained electroencephalography, showing complete electrical silence in the cerebral cortex. An angiography will reveal a cessation of cerebral blood supply. Artificial ventilation and drug support can keep the heart pumping for some time - from a few minutes to several days or even weeks.

The concept of “brain death” is not identical to the concept of biological death, although in fact it means the same thing, since the biological dying of the organism in this case is inevitable.

Time of biological death

Determining the time of onset of biological death is of great importance for ascertaining the circumstances of the death of a person who died in non-obvious conditions.

The less time has passed since death, the easier it is to determine the time of its occurrence.

The age of death is determined by various indications when examining the tissues and organs of a corpse. Determining the moment of death in the early period is carried out by studying the degree of development of cadaveric processes.

Ascertainment of death

The biological death of a person is determined by a set of signs - reliable and orienting.

In case of death from an accident or violent death, it is fundamentally impossible to declare brain death. Breathing and heartbeat may not be audible, but this also does not mean the onset of biological death.

Therefore, in the absence of early and late signs of dying, the diagnosis of “brain death”, and therefore biological death, is established by a doctor in a medical institution.

Transplantology

Biological death is a state of irreversible death of an organism. After a person dies, his organs can be used as transplants. The development of modern transplantology allows us to save thousands of human lives every year.

The moral and legal issues that arise seem to be quite complex and are resolved in each case individually. The consent of the relatives of the deceased for the removal of organs is required.

Organs and tissues for transplantation must be removed before early signs of biological death appear, that is, in the shortest possible time. Late declaration of death—about half an hour after death—makes organs and tissues unsuitable for transplantation.

The removed organs can be stored in a special solution for 12 to 48 hours.

In order to remove the organs of a deceased person, biological death must be established by a group of doctors with the drawing up of a protocol. The conditions and procedure for removing organs and tissues from a deceased person are regulated by the law of the Russian Federation.

The death of a person is a socially significant phenomenon, including a complex context of personal, religious and social relationships. However, dying is an integral part of the existence of any living organism.

Man, like every living organism on Earth, begins his journey with birth and inevitably ends with death. This is a normal biological process. This is the law of nature. You can extend life, but it is impossible to make it eternal. People dream, create a lot of theories, offer different ideas about eternal life. Unfortunately, so far they are unjustified. And it’s especially offensive when life is cut short not because of old age, but because of illness (see) or an accident. Clinical and biological death: what do they look like? And why doesn’t life always win?

The concept of clinical and biological death

When all the vital functions of the body cease to function, death occurs. But a person, as a rule, does not die immediately. He goes through several stages before completely saying goodbye to life. The dying process itself consists of 2 phases - clinical and biological death (see).

Signs of clinical and biological death give us the opportunity to consider how a person dies and, possibly, save him. Knowing the features and first symptoms of clinical death, as well as early signs of biological death, you can accurately determine the person’s condition and begin resuscitation.

Clinical death is considered a reversible process. This is the intermediate moment between a living organism and an already dead one. It is characterized by cessation of breathing and cardiac arrest and ends with physiological processes in the cerebral cortex, which are considered irreversible. The maximum duration of this period is 4-6 minutes. At low ambient temperatures, the time for reversible changes doubles.

Important! Having discovered that there is no pulse in the carotid artery, immediately begin resuscitation without wasting a minute. You need to remember how it is carried out. Sometimes situations arise when someone's life is in your hands.

Biological death is an irreversible process. Without access to oxygen and nutrients, cells of various organs die, and it is not possible to revive the body. He will no longer be able to function, the person can no longer be revived. This is the difference between clinical death and biological death. They are separated by a period of only 5 minutes.

Signs of clinical and biological death

When clinical death occurs, all manifestations of life are absent:

no pulse;
no breathing;
the central nervous system is “disabled”;
there is no muscle tone;
skin color changes (pallor).

But unbeknownst to us, at a very low level, metabolic processes are still ongoing, the tissues are viable and can still be fully restored. The time period is determined by the work of the cerebral cortex. Once nerve cells die, there is no way to completely restore a person.

Not all organs die immediately; some retain the ability to live for some time. After a few hours, you can revive the heart and respiratory center. Blood retains its properties for several hours.

Biological death happens:

physiological or natural, which occurs during the aging of the body;
pathological or premature, associated with serious illness or non-life-threatening injuries.

In both cases, it is impossible to bring a person back to life. Signs of biological death in humans are expressed as follows:

cessation of heart rhythm for up to 30 minutes;
lack of breathing;
dilated pupil that does not respond to light;
the appearance of dark blue spots on the surface of the skin.

An early symptom of biological death is the “cat pupil sign.” When you press on the side of the eyeball, the pupil becomes narrow and oblong, like a cat's.

Since organs do not die immediately, they are used in transplantology for organ transplantation. Patients whose kidneys, hearts, and other organs are failing are waiting for their donor. In European countries, people obtain paperwork to allow their organs to be used if they die in an accident.

How to make sure a person is dead?

Diagnosis of clinical and biological death is important; it is carried out by doctors. But everyone should know how to determine it. Irreversible death of a person can be determined by the following signs:

"Symptom of a cat's pupil."
The cornea of the eye dries out and becomes cloudy.
The formation of cadaveric spots due to decreased vascular tone. They usually occur several hours later, when a person has died.
Decreased body temperature.
Rigor mortis also sets in after a few hours. The muscles become hard and the body becomes inactive.

Doctors diagnose a reliable sign of biological death using data from medical equipment, which determines that electrical signals are no longer coming from the cerebral cortex.

In what cases can a person be saved?

Clinical death differs from biological death in that a person can still be saved. An accurate signal of clinical death is considered if the pulse in the carotid artery is not heard and there is no breathing (see). Then resuscitation actions are carried out: indirect cardiac massage, injection of adrenaline. In medical institutions with modern equipment, such measures are more effective.

If the person shows minimal signs of life, immediate revival is performed. If there is any doubt about biological death, resuscitation measures are taken to prevent the person’s death.

It is also worth paying attention to the harbingers of clinical death:

reduction in blood pressure to critical levels (below 60 mm Hg);
bradycardia (pulse below 40 beats per minute);
increased heart rate and extrasystole.

Important! Establishing a diagnosis of clinical death should take no more than 10 seconds for the person providing assistance! Revival measures taken no later than two minutes after the first signs of clinical death appear are successful in 92% of cases.

Will the person be saved or not? At some stage, the body loses strength and stops fighting for life. Then the heart stops, breathing stops and death occurs.

The death of a person is the complete cessation of biological and physiological processes in his body. The fear of making a mistake in recognizing it forced doctors and researchers to develop accurate methods for diagnosing it and identifying the main signs indicating the onset of death of the human body.

In modern medicine, clinical and biological (final) death are distinguished. Brain death is considered separately.

We will talk about what the main signs of clinical death look like, as well as how biological death manifests itself in this article.

What is clinical death of a person

This is a reversible process, which means stopping the heartbeat and breathing. That is, life in a person has not yet died out, and, therefore, restoration of vital processes with the help of resuscitation actions is possible.

Later in the article, the comparative signs of biological and clinical death will be discussed in more detail. By the way, the human condition between these two types of death of the body is called terminal. And clinical death may well move into the next, irreversible stage - biological, an indisputable sign of which is the rigor of the body and the subsequent appearance of cadaveric spots on it.

What are the signs of clinical death: preagonal phase

Clinical death may not occur immediately, but may go through several phases, characterized as preagonal and agonal.

The first of them manifests itself in inhibition of consciousness while it is preserved, as well as in dysfunction of the central nervous system, expressed by stupor or coma. The pressure, as a rule, is low (maximum 60 mm Hg), and the pulse is rapid, weak, shortness of breath appears, and the breathing rhythm is disturbed. This condition can last for several minutes or several days.

The preagonal signs of clinical death listed above contribute to the appearance of oxygen starvation in tissues and the development of so-called tissue acidosis (due to a decrease in pH). By the way, in the preagonal state the main type of metabolism is oxidative.

Manifestation of agony

The onset of agony is marked by a short series of breaths, and sometimes by a single breath. Due to the fact that a dying person has simultaneous excitation of the muscles that carry out both inhalation and exhalation, ventilation of the lungs almost completely stops. The higher parts of the central nervous system are switched off, and the role of the regulator of vital functions, as proven by researchers, at this moment passes to the spinal cord and medulla oblongata. This regulation is aimed at mobilizing the last possibilities of preserving the life of the human body.

By the way, it is during agony that a person’s body loses that notorious 60-80 g of weight, which is attributed to the soul leaving it. True, scientists prove that in fact weight loss occurs due to the complete combustion of ATP in the cells (enzymes that supply energy to the cells of a living organism).

The agonal phase is usually accompanied by a lack of consciousness. A person's pupils dilate and do not respond to light. Blood pressure cannot be determined; the pulse is practically not palpable. In this case, the heart sounds are muffled, and breathing is rare and shallow. These signs of clinical death, which is approaching, can last several minutes or several hours.

How does the state of clinical death manifest?

When clinical death occurs, breathing, pulse, blood circulation and reflexes disappear, and cellular metabolism proceeds anaerobically. But this does not last long, because the amount of energy in the dying person’s brain is depleted, and his nervous tissue dies.

By the way, modern medicine has established that after the cessation of blood circulation, the death of different organs in the human body does not occur simultaneously. So, the brain dies first, because it is most sensitive to lack of oxygen. After 5-6 minutes, irreversible changes occur in brain cells.

Signs of clinical death are: pale skin (they become cold to the touch), absence of breathing, pulse and corneal reflex. In this case, urgent resuscitation measures should be carried out.

Three main signs of clinical death

The main signs of clinical death in medicine include coma, apnea and asystole. We will look at each of them in more detail.

Coma is a serious condition that is manifested by loss of consciousness and loss of central nervous system functions. As a rule, its onset is diagnosed if the patient’s pupils do not react to light.

Apnea - cessation of breathing. It is manifested by a lack of movement of the chest, which indicates a cessation of respiratory activity.

Asystole is the main sign of clinical death, expressed by cardiac arrest together with the absence of bioelectrical activity.

What is sudden death

A special place in medicine is given to the concept of sudden death. It is defined as non-violent and occurring unexpectedly within 6 hours after the onset of the first acute symptoms.

This type of death includes cases of cessation of heart function that occur for no apparent reason, which are caused by the occurrence of ventricular fibrillation (scattered and uncoordinated contraction of certain groups of muscle fibers) or (less often) acute weakening of heart contractions.

Signs of sudden clinical death are manifested by loss of consciousness, pale skin, cessation of breathing and pulsation in the carotid artery (by the way, it can be determined by placing four fingers on the patient’s neck between the Adam’s apple and the sternocleidomastoid muscle). Sometimes this condition is accompanied by short-term tonic convulsions.

In medicine, there are a number of other causes that can cause sudden death. These include electrical injuries, lightning, suffocation due to a foreign body entering the trachea, as well as drowning and freezing.

As a rule, in all these cases, a person’s life directly depends on the efficiency and correctness of resuscitation measures.

How is cardiac massage done?

If the patient shows the first signs of clinical death, he is placed on his back on a hard surface (floor, table, bench, etc.), the belts are unfastened, restrictive clothing is removed and chest compressions begin.

The sequence of resuscitation actions looks like this:

the person providing assistance takes a place to the left of the victim;
places hands one on top of the other on the lower third of the sternum;
pushes (15 times) at a rate of 60 times per minute, using your body weight to achieve a flexion of the chest of approximately 6 cm;
then grabs the chin and pinches the nose of the dying person, throws back his head, exhales as much as possible into his mouth;
artificial respiration is done after 15 massage pushes in the form of two exhalations into the mouth or nose of the dying person for 2 seconds each (you need to make sure that the victim’s chest rises).

Indirect massage helps compress the heart muscle between the chest and spine. Thus, the blood is pushed into large vessels, and during the pause between beats the heart is filled with blood again. In this way, cardiac activity is resumed, which after some time can become independent. The situation can be checked after 5 minutes: if the victim’s signs of clinical death disappear and a pulse appears, the skin turns pink and the pupils constrict, then the massage was effective.

How does an organism die?

Different human tissues and organs have different resistance to oxygen starvation, as mentioned above, and their death after the heart stops occurs in different time periods.

As is known, the cerebral cortex dies first, then the subcortical centers, and finally the spinal cord. Four hours after the heart stops working, the bone marrow dies, and a day later the destruction of human skin, tendons and muscles begins.

How does brain death manifest?

From the above, it is clear that accurately determining the signs of a person’s clinical death is very important, because from the moment the heart stops until the onset of brain death, leading to irreparable consequences, there are only 5 minutes.

Brain death is the irreversible cessation of all its functions. And its main diagnostic sign is the absence of any reactions to stimulation, which indicates the cessation of the functioning of the hemispheres, as well as the so-called EEG silence even in the presence of artificial stimulation.

Doctors also consider the absence of intracranial circulation to be a sufficient sign of brain death. And, as a rule, this means the onset of biological death of a person.

What does biological death look like?

To make it easier to navigate the situation, you should distinguish between the signs of biological and clinical death.

Biological or, in other words, the final death of the body is the last stage of dying, which is characterized by irreversible changes developing in all organs and tissues. In this case, the functions of the main body systems cannot be restored.

The first signs of biological death include the following:

when pressing on the eye there is no reaction to this irritation;
the cornea becomes cloudy, drying triangles form on it (the so-called Larche spots);
if the eyeball is gently squeezed from the sides, the pupil turns into a vertical slit (the so-called “cat’s eye” symptom).

By the way, the signs listed above also indicate that death occurred at least an hour ago.

What happens during biological death

The main signs of clinical death are difficult to confuse with late signs of biological death. The latter appear:

redistribution of blood in the body of the deceased;
purple cadaveric spots, which are localized in lower places on the body;
rigor mortis;
and, finally, cadaveric decomposition.

The cessation of blood circulation causes a redistribution of blood: it collects in the veins, while the arteries are practically empty. The post-mortem process of blood coagulation occurs in the veins, and with a quick death there are few clots, and with a slow death there are many.

Rigor mortis usually begins in the facial muscles and hands of a person. And the time of its appearance and the duration of the process strongly depend on the cause of death, as well as on the temperature and humidity at the location of the dying person. Typically, the development of these signs occurs within 24 hours after death, and after 2-3 days after death they disappear in the same sequence.

A few words in conclusion

To prevent the onset of biological death, it is important not to waste time and provide the necessary assistance to the dying person.

It must be taken into account that the duration of clinical death directly depends on what caused it, what age the person is, as well as on external conditions.

There are cases where signs of clinical death could be observed for half an hour if it occurred, for example, due to drowning in cold water. Metabolic processes throughout the body and in the brain in such a situation slow down greatly. And with artificial hypothermia, the duration of clinical death is increased to 2 hours.

Severe blood loss, on the contrary, provokes the rapid development of pathological processes in nerve tissues even before cardiac arrest, and restoration of life in these cases is impossible.

According to the instructions of the Russian Ministry of Health (2003), resuscitation measures are stopped only when a person’s brain death is determined or if medical care provided within 30 minutes is ineffective.

The main personal and intellectual characteristics that determine a person’s personality are associated with the functions of his brain. Therefore, brain death must be considered as the death of a person, and a violation of the regulatory functions of the brain quickly leads to disruptions in the functioning of other organs and the death of a person. Cases of primary brain damage leading to death are relatively rare. In other cases, brain death occurs due to circulatory disorders and hypoxia.

Large neurons of the cerebral cortex are very sensitive to hypoxia. Irreversible changes in them occur within 5-6 minutes after the cessation of blood circulation. This period of acute hypoxia, when blood circulation and (or) breathing has already stopped, but the cerebral cortex has not yet died, is called clinical death. This condition is potentially reversible because if cerebral perfusion with oxygenated blood is restored, brain viability is maintained. If oxygenation of the brain is not restored, then the cortical neurons will die, which will mark the onset of biological death, an irreversible condition in which the salvation of a person is no longer possible.

The duration of the period of clinical death is influenced by various external and internal factors. This time period increases significantly during hypothermia, since as the temperature drops, the need for oxygen by brain cells decreases. Reliable cases of successful resuscitation within up to 1 hour after respiratory arrest due to hypothermia have been described. Some medications that inhibit metabolism in nerve cells also increase their resistance to hypoxia. These drugs include barbiturates, benzodiazepines and other antipsychotics. With fever, endogenous purulent intoxication, and jaundice, on the contrary, the period of clinical death is reduced.

At the same time, in practice it is impossible to reliably predict how much the duration of the period of clinical death has increased or decreased and one has to focus on average values of 5-6 minutes.

Signs of clinical and biological death

Signs of clinical death are :

Respiratory arrest, ascertained by the absence of respiratory movements of the chest . Other methods for diagnosing apnea (vibration of a thread brought to the nose by a current of air, fogging of a mirror brought to the mouth, etc.) are unreliable, since they give a positive result even with very shallow breathing, which does not provide effective gas exchange.

Circulatory arrest, ascertained by the absence of pulse in the carotid and (or) femoral arteries . Other methods (listening to heart sounds, determining the pulse in the radial arteries) are unreliable, since heart sounds can be heard even with ineffective, discoordinated contractions, and the pulse in the peripheral arteries may not be determined due to their spasm.

Loss of consciousness (coma) with dilated pupils and lack of reaction to light talk about deep hypoxia of the brain stem and inhibition of the functions of stem structures.

The list of signs of clinical death could be continued, including suppression of other reflexes, ECG data, etc., however, from a practical point of view, the determination of these symptoms should be considered sufficient to establish this condition, since determining a large number of symptoms will take more time and delay the start of resuscitation measures.

Numerous clinical observations have established that after breathing stops, circulatory arrest develops on average after 8-10 minutes; loss of consciousness after stopping blood circulation - after 10-15 seconds; dilation of the pupil after stopping blood circulation - after 1-1.5 minutes. Thus, each of the listed signs must be considered a reliable symptom of clinical death, which inevitably entails the development of other symptoms.

Signs of biological death or reliable signs of death appear 2-3 hours after its actual onset and are associated with the onset of necrobiotic processes in tissues. The most characteristic of them are:

Rigor mortis is that the muscles of the corpse become more dense, due to which a slight bending of the limbs may even be observed. The onset of rigor mortis depends on the ambient temperature. At room temperature, it becomes noticeable after 2-3 hours, is expressed 6-8 hours after death, and after a day it begins to resolve, and completely disappears by the end of the second day. At higher temperatures this process goes faster, at low temperatures it goes slower. In the corpses of emaciated, weakened patients, rigor mortis is poorly expressed.

Cadaveric spots are bluish-purple bruises that appear at the points of contact of the corpse with a solid support. In the first 8-12 hours, when the position of the corpse changes, cadaveric spots can move under the influence of gravity, then they are fixed in the tissues.

Symptom of "cat pupil" lies in the fact that when the eyeball of a corpse is compressed from the sides, the pupil takes on an oval and then a slit-like shape, like a cat’s, which is not observed in living people and in a state of clinical death.

The list of signs of biological death could also be continued, however, these signs are the most reliable and sufficient for practical activities.

An extremely important fact is that quite a significant amount of time passes between the moment of development of biological death and the appearance of its reliable signs - at least 2 hours. During this period, if the time of circulatory arrest is unknown, the patient’s condition should be regarded as clinical death, since there are no reliable signs of biological death.