Clinical death. Clinical death and coma difference The concept of clinical and biological death: definition, signs, causes

What is the difference between coma and clinical death?

Coma is close to normal sleep. That is, the person is simply sleeping. The subconscious forces him to be in this state. It’s just that a person has lost the meaning of life and decided to rest a little until the meaning is found. But clinical death is death; this condition is removed by sudden actions, such as cardiac stimulation, etc. and here the meaning of life has nothing to do with it, a person will no longer get out of such a state without outside help.

Clinical death refers to a condition associated with the absence of hemodynamically effective contractions of the heart and blood circulation, against the background of which anoxia of the brain quickly develops, which leads to the cessation of its functioning within a minute. Within 2-3 minutes, changes in the nerve cells of the brain are still reversible (with hypothermia this time is extended), and then the cells begin to die, so after 4-6 minutes of lack of blood circulation it is no longer possible to restore the full functioning of the brain. Thus, clinical death is a very short-term state that quickly turns into biological death.

Coma is a depression of consciousness and brain activity that is associated with organic or metabolic changes, which can be reversible or irreversible, and can also ultimately lead to brain death - but in general it usually develops much more slowly. The activity of the brain stem fades especially slowly, so that vital functions do not begin to be disrupted immediately.

I think you know the answer. Death is cardiac arrest, clinical death is temporary death. Coma is not death, a person is in an unconscious state while the heart is working, it is possible that his life is supported by drugs and devices.

If clinical death is not pumped out in time, minutes count, oxygen supply to the brain, etc. then biological death occurs. From which, unlike the clinical one, there is no turning back...

And coma is just a dream, blackness from which there is a chance to crawl out.

Sometimes doctors even put especially severe cases into an artificial coma. So that the person gets well soon.

With any type of coma, the heartbeat and blood circulation are preserved to one degree or another; breathing in some types of coma (for example, diaphragm injury) can be practically unnoticeable, or even completely absent, then ventilators are connected. In clinical death, both breathing and heartbeat stop completely; this is the main difference. Again, a person cannot come out of a state of clinical death on his own, but he can come out of a coma.

If a person can live without food for a month, without water for several days, then the interrupted access of oxygen will cause breathing to stop within 3-5 minutes. But it’s too early to talk about final death right away, because clinical death occurs. This condition occurs when blood circulation and oxygen transfer to tissues stop.

Up to a certain point, a person can still be brought back to life, because irreversible changes have not yet affected the organs, and most importantly, the brain.

Manifestations

This medical term implies the simultaneous cessation of respiratory function and blood circulation. According to the ICD, the condition was assigned code R 96 - death occurred suddenly for unknown reasons. You can recognize being on the verge of life by the following signs:

There is a loss of consciousness, which entails a cessation of blood flow.
There is no pulse for more than 10 seconds. This already indicates a violation of the blood supply to the brain.
Stopping breathing.
The pupils are dilated, but do not react to light.
Metabolic processes continue to occur at the same level.

Back in the 19th century, the listed symptoms were quite enough to declare and issue a person’s death certificate. But now the possibilities of medicine are enormous and doctors, thanks to resuscitation measures, may well be able to bring him back to life.

Pathophysiological basis of CS

The duration of such clinical death is determined by the time period during which brain cells are able to remain viable. According to doctors, there are two terms:

The duration of the first stage is no longer than 5 minutes. During this period, the lack of oxygen supply to the brain does not yet lead to irreversible consequences. Body temperature is within normal limits.

The history and experience of doctors shows that it is possible to revive a person after a given time, but there is a high probability of the death of most of the brain cells.

The second stage can continue for a long time if the necessary conditions are created to slow down degenerative processes with impaired blood supply and oxygen supply. This stage is often observed when a person spends a long time in cold water or after an electric shock.

If action is not taken to bring the person back to life as soon as possible, then everything will end in biological care.

Causes of the pathological condition

This condition usually occurs when the heart stops. This can be caused by serious diseases, the formation of blood clots that clog important arteries. The reasons for the cessation of breathing and heartbeat may be as follows:

Excessive physical activity.
A nervous breakdown or the body's reaction to a stressful situation.
Anaphylactic shock.
Choking or blockage respiratory tract.
Electric shock.
Violent death.
Vasospasm.
Serious illnesses affecting the blood vessels or organs of the respiratory system.
Toxic shock from exposure to poisons or chemicals.

No matter the cause of this condition, during this period resuscitation should be carried out immediately. Delay is fraught with serious complications.

Duration

If we consider the entire body as a whole, then the period of preservation of normal viability is different for all systems and organs. For example, those located below the heart muscle are able to continue normal functioning for another half hour after cardiac arrest. Tendons and skin have a maximum survival period; they can be resuscitated 8-10 hours after the death of the body.

The brain is most sensitive to oxygen deficiency, so it suffers first. A few minutes are enough for his final death. That is why resuscitators and those who happened to be close to the person at that moment have a minimum amount of time to determine clinical death - 10 minutes. But it is advisable to spend even less, then the health consequences will be insignificant.

Introduction to the CS state artificially

There is a misconception that an artificially induced coma is the same as clinical death. But this is far from true. According to WHO, euthanasia is prohibited in Russia, and this is artificially induced care.

Induction into a medically induced coma is practiced. Doctors resort to it to avoid disorders that can adversely affect the brain. In addition, a coma helps to spend several in a row urgent operations. Finds its application in neurosurgery and treatment of epilepsy.

Coma or drug-induced sleep is caused by the administration of medications only as indicated.

An artificial coma, unlike clinical death, is completely controlled by specialists and a person can be taken out of it at any time.

One of the symptoms is coma. But clinical and biological death are completely different concepts. Often, after being revived, a person falls into a coma. But doctors are confident that the body’s vital functions have been restored and recommend that relatives be patient.

How is it different from coma?

The comatose state has its own character traits, which fundamentally distinguish it from clinical death. The following distinctive features can be mentioned:

During clinical death, the work of the heart muscle suddenly stops and breathing movements stop. Coma is simply a loss of consciousness.
In a comatose state, a person continues to breathe instinctively; one can feel the pulse and listen to the heartbeat.
The duration of the coma can vary, from several days to months, but the borderline vital state will turn into biological withdrawal in 5-10 minutes.
According to the definition of coma, all vital functions are preserved, but may be suppressed or impaired. However, the outcome is the death of first the brain cells, and then the entire organism.

Will the comatose state end as the initial stage of clinical death? complete care whether a person is from life or not depends on the speed of medical care.

Difference between biological and clinical death

If it so happens that at the moment of clinical death there is no one near the person who could take resuscitation measures, then the survival rate is practically zero. After 6, maximum 10 minutes, complete death of brain cells occurs, any rescue measures are pointless.

The undeniable signs of final death are:

Clouding of the pupil and loss of luster of the cornea.
The eye shrinks and the eyeball loses its normal shape.
Another difference between clinical and biological death is a sharp drop in body temperature.
Muscles become dense after death.
Corpse spots appear on the body.

If the duration of clinical death can still be discussed, then for biological death there is no such concept. After the irreversible death of the brain, the spinal cord begins to die, and after 4-5 hours the functioning of the muscles, skin, and tendons stops.

First aid in case of CS

Before starting resuscitation, it is important to make sure that the CS phenomenon is occurring. Seconds are allotted for the assessment.

The mechanism is as follows:

Make sure there is no consciousness.
Make sure the person is not breathing.
Check pupil reaction and pulse.

If you know the signs of clinical and biological death, then diagnosing a dangerous condition will not be difficult.

The further algorithm of actions is as follows:

To clear the airways, to do this, remove the tie or scarf, if any, unbutton the shirt and pull out the sunken tongue. In medical institutions, breathing masks are used at this stage of care.
Make a sharp blow to the heart area, but this action should only be done by a competent resuscitator.
Artificial respiration and indirect cardiac massage are performed. Fulfill cardiopulmonary resuscitation necessary before the ambulance arrives.

At such moments, a person realizes that life depends on competent actions.

Resuscitation in a clinical setting

After the ambulance arrives, doctors continue to bring the person back to life. Carrying out ventilation of the lungs, which is performed using breathing bags. The difference between this type of ventilation is the supply to lung tissue mixtures of gases with an oxygen content of 21%. At this time, the doctor may well perform other resuscitation actions.

Heart massage

Most often, simultaneously with ventilation of the lungs, indoor massage hearts. But during its implementation, it is important to correlate the force of pressure on the sternum with the age of the patient.

In infants, the sternum should not move more than 1.5-2 centimeters during a massage. For children school age the depth can be 3-3.5 cm with a frequency of up to 85-90 per minute; for adults, these figures are 4-5 cm and 80 pressures, respectively.

There are situations when it is possible to perform an open massage of the heart muscle:

If cardiac arrest occurs during surgery.
Pulmonary embolism occurs.
Fractures of the ribs or sternum are observed.
Closed massage does not give results after 2-3 minutes.

If cardiac fibrillation is determined using a cardiogram, then doctors resort to another method of revival.

This procedure can be of different types, which differ in technique and implementation features:

Chemical. Potassium chloride is administered intravenously, which stops fibrillation of the heart muscle. Currently, the method is not popular due to the high risk of asystole.
Mechanical. It also has a second name: “reanimation strike.” A regular punch is made to the sternum area. Sometimes the procedure can give the desired effect.
Medical defibrillation. The victim is administered antiarrhythmic drugs.
Electric. Used to start the heart electricity. This method is used as soon as possible, which significantly increases the chances of life during resuscitation.

For successful defibrillation, it is important to correctly position the device on chest, choose the current strength depending on age.

First aid for clinical death, provided in a timely manner, will bring a person back to life.

The study of this condition continues to this day; there are many facts that even competent scientists cannot explain.

Consequences

Complications and consequences for a person will depend entirely on how quickly help was provided to him and how effective resuscitation measures were used. The faster the victim can be brought back to life, the more favorable the prognosis for health and psyche will be.

If you managed to spend only 3-4 minutes on revival, then there is a high probability that there will be no negative manifestations. In the case of prolonged resuscitation, the lack of oxygen will have a detrimental effect on the condition of the brain tissue, up to their complete death. To slow down degenerative processes, pathophysiology recommends deliberately cooling the human body at the time of resuscitation in case of unforeseen delays.

Through the eyes of eyewitnesses

After a person returns to this sinful earth from a suspended state, it is always interesting what can be experienced. Those who survived talk about their feelings like this:

They saw their body as if from the outside.
Complete calm and tranquility ensues.
Moments of life flash before your eyes, like stills from a movie.
The feeling of being in another world.
Encounters with unknown creatures.
They remember that a tunnel has appeared that they need to go through.

Among those who experienced this borderline state many famous people, for example, Irina Panarovskaya, who became ill right at the concert. Oleg Gazmanov lost consciousness when he was electrocuted on stage. Andreichenko and Pugacheva also experienced this state. Unfortunately, the stories of people who experienced clinical death cannot be 100% verified. You can only take my word for it, especially since similar sensations are observed.

Scientific view

If lovers of esotericism see in stories a direct confirmation of the existence of life on the other side, then scientists try to give natural and logical explanations:

Flickering lights and sounds appear at the very first moment the blood flow through the body stops.
During clinical death, the concentration of serotonin rises sharply and causes peace.
The lack of oxygen also affects the organ of vision, which is why hallucinations with lights and tunnels appear.

The diagnosis of CS is a phenomenon that is interesting to scientists, and only thanks to high level medicine managed to save thousands of lives and prevent them from crossing that line where there is no turning back.

The severe unstable condition of a patient with a 3rd degree coma can progress until a 4th degree coma develops. This is a transcendental state, which is characterized by deep depression of all body functions. Life support is possible with the help of artificial respiration devices, parenteral nutrition and medicines.

Causes

A terminal condition occurs as a complication of a serious illness that cannot be treated:

Diabetes mellitus, hypothyroidism.
Tumors.
Severe intoxication, poisoning with ethanol, drugs.

Clinical manifestations

The patient's reflexes completely disappear, muscle atonia develops, and he does not respond to pain and exogenous stimuli. Blood pressure is maximally reduced, pulse is frequent or pathologically slow. Breathing is difficult, unproductive, and apnea may develop. The pupils are dilated and do not constrict to light. Body temperature drops. Absence noted bioelectrical activity brain

Management of a patient in a coma

If the patient’s condition sharply worsens and there are suggestions of brain death, emergency measures are necessary:

Connecting an artificial respiration device.
Maintaining blood pressure with medications.
Providing venous access by installing a catheter in the central vein.
Feeding through a gastric tube.
Prevention of bedsores and pneumonia.

Forecast! In a stage 4 coma, the chances of survival are negligible. If within 20-30 minutes during resuscitation measures it was possible to achieve restoration of spontaneous breathing, spinal or brainstem reflexes, electrical impulses of the brain, then stabilization of such a patient is possible. Otherwise, the outcome will be brain death.

Brain death

Based on data indicating the cessation of functioning of the brain and its stem, brain death is confirmed by a council of doctors. This concept is legally enshrined and defines the death of a person, despite the presence of cardiac activity and breathing supported artificially. Life support systems have a high cost, so at a certain stage the question is raised about disconnecting the patient from life support devices. This creates the possibility of obtaining donor organs for transplantation.

The following criteria for brain death have been defined:

Damage to the brain structure. There must be a history of trauma, after which it is impossible to definitely restore its structure. Diagnosis is carried out using.
Full examination confirms that the depressed state is not caused by intoxication.
Body temperature 32°C or more. A hypothermic state can lead to a decrease in electrical activity on the EEG, but when the temperature rises, the indicators are restored.
The observation period for injuries ranges from 6 to 24 hours; after drug intoxication and in children, the observation time is increased.
Does not react with movement to severe pain, there are no reflex reactions to pain in the form of rapid breathing or heartbeat.
Apnea is confirmed by a special test. Ventilation of the lungs is carried out with pure humidified oxygen or mixed with carbon dioxide for 10 minutes. After this, its feed is reduced. Spontaneous breathing should return within 10 minutes. If this does not happen, brain death is diagnosed.
Absence of corneal reflexes: no eye movement during cold testing, fixed pupils, corneal, pharyngeal, vomiting reflex, blinking, swallowing.
EEG in the form of an isoelectric line.
According to angiography, there is no blood flow. During ophthalmoscopy, glued red blood cells are found in the retina - a sign of stopping blood flow.

Pseudocomatose states

Coma state 4 must be differentiated from other conditions that are accompanied by similar symptoms:

Locked-in syndrome. Damage to the motor tract leads to paralysis of the muscles of the limbs, neck and face, and is a consequence of blockage of the main artery or tumor of the bridge, a demyelinating process. Patients cannot move or pronounce words, but understand speech, blink, and move their eyes.
Akinetic mutism. Stroke, injury to the thalamus, midbrain, caudate nucleus, motor and sensory pathways are damaged, paresis or paralysis of the muscles of the limbs develops, and speech is lost. A person can open his eyes, sometimes perform some movements or pronounce words in response to a painful stimulus. But wakefulness takes place without the participation of consciousness. After recovery, the patient remains amnesic.
Abulia. The lesions are located in the temporal lobes, midbrain and caudate nucleus. The ability to move and speak is impaired. Sometimes patients can emerge from this state and respond adequately to stimuli, and then return to their original state.
Severe depression. Accompanied by a state of stupor, complete immobilization and loss of contact are possible. The condition develops gradually. Diagnostic CT or MRI does not reveal signs of brain damage.
Hysteria. People with pronounced affective behavior after a traumatic situation experience complete immobilization and withdrawal. Signs of organic damage brain structures No.

Results

The outcome of coma 4 can be a vegetative state. It is characterized by alternating sleep and wakefulness, but it is impossible to establish contact, there is no awareness of the individual. Breathing is spontaneous, blood pressure and cardiac activity are stable. Movements are possible in response to stimuli. This condition lasts for at least a month. It will never be possible to get out of it. Higher brain functions are not restored. The patient's death occurs from additional complications.

Clinical death is a transitional stage between life and biological death. In this case, the central nervous system does not function, but the metabolic process still occurs in the tissues. Sometimes clinical death is identified with another condition - coma.

Differences between coma and clinical death

Clinical death and coma are not identical concepts. Coma is before serious condition, in which there is a progressive inhibition of all functions of the central nervous system: impaired reactions to external stimuli, loss of consciousness. In this state, a person retains the ability to breathe and his heart beats. This is determined by the pulse on main arteries.

Coma can progress to a deep coma, which causes brain damage.

In its initial form, this condition may be one of the signs of clinical death. However, unlike coma, clinical death is not only loss of consciousness, but also cessation of breathing and cessation of heart contractions. Often, after resuscitation actions when emerging from clinical death, the human body goes into a coma that has varying degrees depths. In this case, doctors determine whether the person managed to emerge from the state of clinical death before receiving brain damage or not. If the brain is damaged, the patient falls into a deep coma.

Signs and stages of clinical death

Signs of clinical death are: absence of heartbeat, general pallor, respiratory arrest, lack of pupillary reaction to light. The central nervous system ceases to function, but metabolic processes in tissues continue to occur. Clinical death has three stages. The first is a preagonal state, a person feels general weakness, consciousness is confused, blueness of the skin or their pallor is observed, absence or weakness of the pulse in the peripheral arteries, it becomes difficult to determine blood pressure. The second stage of clinical death is the agonal stage (agony). During this period, there is a sharp intensification of the activity of all parts of the body. A characteristic external sign of this stage is short, deep breathing accompanied by wheezing. Often there is no consciousness because the functioning of the central nervous system is disrupted. In the third stage, the body gives up and turns off the “life support system.” During this short period, doctors have the opportunity to bring a person back to life; at this time, the accumulated supply of oxygen and necessary substances is consumed in the body’s cells.

If blood flow stops suddenly, it may take up to 10 minutes to die.

If during clinical death no resuscitation actions were carried out, or they were ineffective, biological death occurs, which is irreversible. Clinical death lasts 5-6 minutes following cardiac and respiratory arrest. After this time, it is no longer possible to restore vital functions.