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How does electric current affect a person?

electrical injury

An electric current strikes a person suddenly. The passage of current through the human body causes electrical injuries of a different nature: electric shock, burns, electrical signs-tags.

Electric shock is called electric shock, in which shock occurs, that is, a kind of severe reaction of the body to a strong stimulus - an electric current.

The outcome of the shock is different. In severe cases, shock is accompanied by circulatory and respiratory disorders. Fibrillation of the heart is possible, that is, instead of a simultaneous rhythmic (about 1 time per second) contraction of the heart muscle, a chaotic twitching of its individual fibers - fibrils occurs. This stops the normal functioning of the heart, blood flow stops, and death can occur.

The defeat of a person by current at a voltage of up to 1000 V is in most cases accompanied by an electric shock.

Burns occur when exposed to a significant current (about 1 BUT and more) or from an electric arc. So, when approaching current-carrying parts with a voltage above 1000 V, an unacceptably small distance between the current-carrying part and the human body appears spark discharge, and then an electric arc that causes a severe burn. In case of accidental contact with a live part with a voltage of up to 1000 V, the current passing through the human body heats the tissues up to 60-70°C. This causes the protein to fold. Electrical burns are difficult to heal. They capture a large surface of the body and penetrate deeply.

Electric signs (tags) - this is the necrosis of the skin in the form of a callus yellow color with a gray border at the place of current entry and exit. If the lesion has penetrated deeply, then the tissues of the body gradually die off.

The nature of the impact of the variable electric current depending on its value is given in table. one

From Table. 1 it follows that a current of more than 15 mA is dangerous for a person, at which a person cannot free himself. A current of 50 mA causes severe injury. A current of 100 mA, acting for more than 1-2 seconds, is deadly.

Factors affecting the outcome of the lesion

The magnitude of the electric current passing through the human body, and consequently, the outcome of the lesion depends on many circumstances.

The most dangerous is alternating current with a frequency of 50-500 Hz. Most people retain the ability to independently free themselves from currents of this frequency at very low values ​​​​of it (9-10 mA). Direct current is also dangerous, but it is possible to get rid of it on your own at somewhat large values ​​(20-25 mA).

The magnitude of the current depends on the voltage of the electrical installation and on the resistances of all elements of the circuit through which the current flows, including the resistance of the human body. Body resistance is made up of active and capacitive resistances of the skin and internal organs . Dry, undamaged skin has a resistance of about 100,000 ohms, wet - about 1000 ohms, and the resistance of internal tissues (with the stratum corneum removed) is about 500-1000 ohms. The skin of the face and armpits has the least resistance.

The resistance of the human body is a non-linear quantity. It sharply, disproportionately decreases with an increase in the voltage applied to the body, an increase in the time of exposure to current, with an unsatisfactory physical and mental state, with large and tight contact with the current-carrying part, etc. From fig. 1 it follows that with an increase in the voltage applied to the body from 0 to 140 V, the resistance of the body decreases nonlinearly from tens of thousands to 800 ohms (curve 1). Accordingly, the current passing through the body increases (curve 2).

The resistance of the human body (Ohm) is approximately determined by the formula

Z people \u003d U pr / I people

where U pr- voltage drop across the resistance of the human body - V.

In calculations for electrical safety, it (also approximately) is taken equal to:

Z people = 1000 Ohm

The most dangerous current path through the heart, brain, lungs. Characteristic paths: palm - feet, palm - palm, foot - foot. However, a fatal defeat is also possible when the current passes along a path that, it would seem, does not affect the vital important organs, for example, through the lower leg to the foot. This phenomenon is explained by the fact that the current in the body flows along the path of least resistance (nerves, blood), and not in a straight line - through tissues with high resistance (muscles, fat).

It has been established that the outcome of electric shock depends on the physical and mental state human . If he is hungry, tired, intoxicated or unhealthy, then the likelihood of a severe injury increases. Women, adolescents, men with poor health are able to withstand significantly lower currents (within 6 mA) than healthy men (12-15 mA).

The duration of exposure is one of the main factors affecting the outcome of the lesion. The cycle of the heart is approximately 1 s. There is a phase in the cycle T, equal to 0.1 s, when the heart muscle is relaxed and it is most vulnerable to current: fibrillation may occur. How less time exposure to current (less than 0.1 s), the less likely fibrillation. Prolonged (several seconds) exposure to current leads to a severe outcome: the resistance of the body decreases, and the lesion current increases.

The mechanism of the impact of electric current on a person is complex. On the one hand, in high-voltage installations there were cases when a short-term (hundredths of a second) exposure to a current of several amperes did not lead to death. On the other hand, it has been established that death possible at a voltage of 12-36 V, when a current of several milliamps is applied. This happens as a result of touching the current-carrying part with the most vulnerable part of the body - the back of the hand, cheek, neck, shin, shoulder.

Given the danger of electrical installations with voltages both up to 1000 and above 1000 V, each worker must firmly remember that you can’t touch live parts, no matter what voltage they are under, you can’t get close to live parts in high-voltage installations, you can’t touch them unnecessarily to the metal structures of switchgear, power transmission line supports, to equipment cases that can become energized when current-carrying parts are shorted to them.

Earth faults in electrical installations are usually switched off by the main relay protection in a fraction of a second. Therefore, electrical safety devices (grounding, etc.) can be calculated based on large values admissible current. In this case, a current that does not cause fibrillation in 99.5% of experimental animals, whose body weight and heart weight is close to human, is considered acceptable. Permissible values ​​of current and voltage of contact, obtained in laboratory studies, are given in Table. 2

From Table. 3-2 it follows that currents over 65 mA and voltages over 65 V are allowed for less than 1 s.

The effect of electric current on the human body was already known at the end of the 18th century. However, at that time they did not know that electric current could pose a danger to humans. The first mention of industrial electrical injuries in the means mass media are found in the second half of the 19th century (in 1863 a description of an electrical injury on direct current is given, and in 1882 on an alternating current). At the end of the 19th century, a systematic study of the effect of electric current on the body of animals and humans begins, and measures are being developed to protect humans from current.

Passing through the human body, the electric current has a complex effect on it, which is a combination of:

1. thermal effects - heating of biological tissues, blood vessels, nerves and organs that are in the path of current flow; burns of body parts;
2. electrolytic influence - decomposition of organic liquids (blood and plasma);
3. mechanical impact - ruptures, delamination of tissues and blood vessels, dislocations, etc. due to the electrodynamic effect;
4. biological - irritation and arousal nerve fibers and other tissues of the body.

Any of these effects can lead to human injury in the form of electrical injury, which can be divided into local and general.

Picture. Classification of electrical injuries

Local electrical injuries, in which local (local) damage to the body occurs, include:

1. Electrical burn the most common type of local electrical injury. An electrical burn is the result of an electric arc being applied to a person (arc burn) or an electric current passing through his body (current burn).

A current burn is, as a rule, a skin burn at the point of contact of the human body with the current-carrying part due to the transformation electrical energy into thermal. Since human skin has many times more resistance than other human tissues, it generates most of the heat. Current burns occur, as a rule, in installations up to 1000 V.

An electric arc that causes an arc burn occurs when a discharge occurs through the human body and is accompanied by the passage of current through the human body. Also, an arc burn can occur during short circuits in electrical installations, in which case the current does not flow through the human body. The electric arc has a high temperature, which can cause extensive burns to the body and lead to death. In power plants up to 6 kV, a burn is most often the result of random short circuits. More than high voltage burn occurs:

• when a person accidentally approaches live parts under voltage, at a distance at which a breakdown of the air gap between them occurs;
• in case of damage to insulating protective equipment (rods, voltage indicators, etc.), with which a person touches live parts that are energized;
• during erroneous operations with switching devices (for example, when disconnecting a disconnector under load using a rod), when the arc is often transferred to a person, etc.

There are 4 degrees of electrical burns. I degree burns are characterized by redness of the skin, II degree - the appearance of blisters on the skin, III degree - necrosis of the skin, IV degree - charring of the skin, subcutaneous tissues, muscles and even bones.

2. electrical sign(electrical tag) a specific skin lesion caused by the flow of current through the human body. Electric signs are dead skin areas on the human body at the points of entry and exit of electric current. Generally, electrical signs are painless and treatable.

3. Leather plating caused by the ingress of particles of metal melted under the action of an electric arc onto the human body. The severity of the injury depends on the location and area of ​​the lesion on the human body. Cases of eye damage can be very dangerous, often leading to loss of vision. Simultaneously with the metallization of the skin, an electric arc burn often occurs.

4. Electrophthalmia is an inflammation of the outer membranes of the eyes due to exposure to ultraviolet rays from an electric arc during short circuits in electrical installations.

5. Mechanical damage(ruptures of tendons, skin, blood vessels, dislocations of joints, fractures of bones), occur as a result of sharp, involuntary muscle contractions under the influence of current, or a person falling from a height.

Picture. Approximate distribution of electrical injuries by type of injury

Common electrical injuries that affect the entire body include electric shock. This type of electrical injury is the most common (more than 80% of all human electric shocks). Approximately 85% of fatal electrical shocks are related to electrical shock. Most of of these cases (approximately 60%) is the result of the simultaneous action of electric shocks and local electrical injuries (mainly burns), however, in these cases, death is, as a rule, the result of an electric shock.

Picture. Distribution of cases of electric shock by type of electrical injury

electric shock This is a damage to the human body caused by the excitation of living tissues of the body by electric current and is accompanied by convulsive muscle contraction. Electric shocks occur when relatively small currents (up to several hundred milliamps) and voltages, usually up to 1000 V, flow through the human body. lethal defeat.

Depending on the resulting consequences, electric shocks are divided into four degrees: I - convulsive muscle contraction without loss of consciousness; II - convulsive muscle contraction with loss of consciousness, but with preserved breathing and heart function; III - loss of consciousness and impaired cardiac activity or breathing (or both); IV - the state of clinical death.

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The effect of electric current on the human body. Electricity, acting on the human body, can lead to various injuries: electric shock, burns, skin metallization, electric sign, mechanical damage, electrophthalmia (Table 1).

Table 1. Characteristics of the impact on a person of electric current of various strengths

Current, mA	AC 50 - 60 Hz	D.C
0,6 — 1,5	Slight trembling of the fingers	Not felt
2 — 3	Strong trembling of the fingers	Not felt
5 — 7	Cramps in the hands	3d. Feeling warm
8 — 10	Hands with difficulty, but still can be torn off the electrodes. Severe pain in the arms, especially in the hands and fingers	Heating boost
20 — 25	Hands are paralyzed immediately, it is impossible to tear them off the electrodes. Very severe pain. Difficulty breathing	Even greater increase in heating, slight contraction of the muscles of the hands
50 — 80	Respiratory paralysis. Beginning of ventricular flutter	Strong feeling of warmth. Contraction of the muscles of the hands. Seizures. Difficulty breathing
90 — 100	Paralysis of breathing and heart when exposed to more than 0.1 s.	Respiratory paralysis

electric shock leads to the excitation of living tissues; Depending on the pathological processes caused by electric shock, it is accepted next classification the severity of electrical injury during electric shock:

1. electrical injury of the 1st degree- convulsive muscle contraction without loss of consciousness;

2. electrical injury II degree- convulsive contraction of muscles with loss of consciousness, "

3. electrical injury III degree- loss of consciousness and violation of the functions of cardiac activity or respiration (it is possible both);

4. electrical injury IV degree — clinical death.

Severity electrical shock depends on many factors: the body's resistance, magnitude, duration of action, type and frequency of the current, its path in the body, environmental conditions.

The outcome of electrocution also depends on physical condition person. If he is sick, tired or in a state of intoxication, mental depression, then the action of the current is especially dangerous. Alternating current up to 10 mA and direct current up to 50 mA are considered safe for humans.

Electrical burn various degrees- a consequence of short circuits - in electrical installations and the stay of the body (usually hands) in the sphere of light (ultraviolet) and thermal (infrared) influence of an electric arc; III and IV degree burns with a severe outcome - when a person comes into contact (directly or through an electric arc) with current-carrying parts with a voltage of over 1000 V.

electrical sign(current mark) - specific lesions caused by mechanical, chemical or their combined effects of current. The affected area of ​​the skin is practically painless, there are no inflammatory processes around it. Over time, it hardens and superficial tissues die off. Electrosigns usually heal quickly.

Leather plating- the so-called impregnation of the skin with the smallest vaporous or molten metal particles under the influence of mechanical or chemical action of the current. The affected area of ​​the skin acquires a hard surface and a peculiar color. In most cases, plating heals without leaving marks on the skin. Electrophthalmia is damage to the eyes by ultraviolet rays, the source of which is a voltaic arc. As a result of electrophthalmia, an inflammatory process occurs after a few hours, which disappears if taken necessary measures treatment.

In a production environment, electric shock is most often the result of people touching live parts that are under dangerous voltage.

There are two options for such touches with varying degrees danger. The first, the most dangerous, is the simultaneous touching of two linear wires and the second, less dangerous (there are more such cases) is the touching of one phase.

Single-phase connection to the current circuit: a) with a grounded neutral; b) with isolated neutral

Types of effects of electric current on the body

Electric current has a thermal, electrolytic and biological effect on the human body.
Thermal effect of current manifests itself in burns of certain parts of the body, as well as in heating up to high temperatures other organs.
Electrolytic action of current manifests itself in the decomposition of organic liquids, causing significant violations of their physico-chemical composition.
Biological effect of current manifests itself in irritation and excitation of living tissues of the body, as well as in violation of internal bioelectrical processes.

Types of human electric shock

There are two main types of electric shock to a person:
electrical injuries and electrical shocks.
Types of electrical injuries: local electrical injuries (electric burns, electric signs, skin plating, mechanical damage, electrophthalmia).
Of particular danger are electrical injuries in the form of burns. An electrical burn appears at the point of contact of the human body with the current-carrying part of an electrical installation or an electric arc. Electric burns are cured much more difficult and slower than conventional thermal burns, they are accompanied by sudden bleeding, necrosis of certain parts of the body.
Metallization of the skin is the penetration into its upper layers of the smallest particles of metal that has melted under the influence of an electric arc. The victim at the site of the lesion experiences skin tension from the presence of a foreign body in it and pain from a burn due to hot metal. Metallization is observed in approximately 10% of the victims.
Mechanical damage occurs as a result of sharp, convulsive muscle contractions under the influence of current passing through the human body. As a result, ruptures of the skin, blood vessels, nervous tissue, as well as dislocations of the joints and fractures of the bones.
Electrophthalmia is an inflammation of the outer membranes of the eyes resulting from exposure to a powerful stream of ultraviolet rays that are absorbed by the cells and cause them to chemical changes. Such exposure is possible in the presence of an electric arc.
Electrical signs are clearly defined patches of gray or pale yellow, round or oval shape with a depression in the center, sometimes in the form of scratches, bruises, warts, hemorrhages in the skin, calluses, sometimes resemble the shape of a lightning bolt. Basically, electrical signs are painless. Signs occur in 20% of those affected by the current.

The consequences of the impact of electric current on a person. electric shock

- this is the excitation of the living tissues of the body by an electric current passing through it, accompanied by muscle contractions. The outcome can range from mild to fatal.
Distinguish between clinical and biological death.
Clinical (or "imaginary") - death is a transitional state from life to death, occurring from the moment the activity of the heart and lungs ceases. A person in a state of clinical death lacks all signs of life: he does not breathe, his heart does not work, pain stimuli do not cause any reactions, the pupils of the eyes are sharply dilated and do not react to light. However, during this period, life in the body has not yet completely died out, because its tissues are not yet subject to decay and in to some extent maintain viability. The duration of clinical death is 4-6 minutes, in healthy person- 7-8 min.

Causes of death from electric current

Fibrillation of the heart.
Causes of death from electric current can be cessation of breathing, cessation of the heart and electrical shock. It is also possible for all three causes to work simultaneously.
The cessation of the work of the heart is the result direct impact current to the heart muscle, i.e. the passage of current in the region of the heart or reflexively through the central nervous system when the current path lies outside this region. In both cases, cardiac arrest or fibrillation may occur.
Cardiac fibrillation is a chaotic multi-temporal contraction of the fibers of the heart muscle (fibrils), in which the heart is not able to drive blood through the vessels.

A peculiar severe neuro-reflex reaction of the body in response to excessive irritation with an electric current, accompanied by deep disorders of blood circulation, respiration, and metabolism. state of shock lasts from several tens of minutes to days. After this, either the death of a person may occur as a result of the complete extinction of vitality. important functions, or recovery as a result of timely active therapeutic intervention.

Factors affecting the outcome of the lesion

The outcome of the impact of electric current on a person depends on many factors: on the type of current (alternating or direct); at alternating current- on its frequency), the value of the current (or voltage), the duration of its flow, as well as on the physical and mental state of a person.
The most dangerous for humans is with a frequency of 50 - 500 Hz. The ability to self-liberate from the current of this frequency in most people is maintained at a very low current (up to 10 mA), D.C. is also dangerous, but you can get rid of it yourself with a few large values(up to 20 - 25 mA). A current of about 70 microamperes can be considered safe.
The current passing through the human body depends on the voltage of the electrical installation and the resistance of all elements of the circuit through which it flows, including the resistance of the human body. Electrical resistance The human body consists of the resistance of the skin and the resistance of internal tissues. The highest resistance has the upper stratum corneum of the skin, the thickness of which is fractions of a mm. If the skin is dry, undamaged, its resistance is high, and at a voltage of 10 V it is about 100,000 ohms. If there is damage on the body, its resistance is reduced to 1000 ohms or less (for example, if the skin is damaged at the point of contact with the current-carrying part). The higher the voltage, the sooner the skin breakdown is possible.

What voltage is "safe"?

Each worker must firmly remember that SAFE VOLTAGE DOES NOT EXIST and that live parts must not be touched, regardless of what voltage they are under. If it is necessary to work on or near equipment that may be energized (metal structures of the switchgear, equipment cases, and other parts), protective equipment should be used: grounding, insulation, insulating tools.
The duration of exposure is one of the main factors affecting the outcome of the lesion. The shorter the exposure time (less than I sec), the lower the probability of damage.
If vital organs, such as the heart, lungs, brain, are in the path of the current, then the danger of injury is very high, since the current acts directly on these organs.
If the current passes in other ways, then its effect on the vital organs can only be through the central nervous system. Since the resistance of the skin in different parts of the body is different, the outcome of the lesion depends on the place of contact with current-carrying parts. The most dangerous contact with active (acupuncture) areas. Possible paths there is a lot of current in the human body, which are also called current loops. Sachets of common ones (6 loops): hand-hand, right hand-legs, left hand- legs, leg-leg, head - legs, head - arms.
The most dangerous are the head-arm and head-leg loops, when the current can pass through the head and spinal cord. Fortunately, these loops are relatively rare. The leg-to-leg loop creates the so-called "step stress".

Step voltage

The voltage between two points on the earth's surface, separated from each other by a step distance (0.7-0.8 m), in the zone of spreading of fault currents within a radius of up to 20 m during the breakdown of insulation to the ground of an accidentally broken electrical wire is called step voltage. the largest value step voltage will be when a person approaches a fallen wire, and the smallest - when he is at a distance of 20 m or more from him. When exposed to stepping voltage, involuntary convulsive contractions of the leg muscles occur and, as a result, a person falls to the ground. At this moment, the action of the step voltage on the person stops and a different, more difficult situation arises: instead of the lower loop, a new, more dangerous path current, usually from the hands to the feet and is created real threat fatal electric shock. When exposed to step voltage, it is necessary to exit from danger zone minimal steps or jumps on one leg.

Human susceptibility to electric current

It has been established by practice that quite healthy and physically strong people endure it more easily than the sick and weak.
Persons suffering from a number of diseases, primarily diseases of the skin, cardiovascular system, organs of internal secretion, lungs, have an increased susceptibility to electric current. nervous diseases and etc.
The mental state of a person at the moment of defeat has, if not more, then at least the same significance for the outcome of the defeat, as the resistance of the human body and his other physical data. For example, the “Attention Factor”, that is, the mental preparedness of a person for possible dangers of electric shock, is of considerable importance. The fact is that the unexpected, even with a relatively small voltage, often leads to serious consequences; if a person is prepared for a strike, i.e. awaits him, the degree of danger is sharply reduced.

Psychological preparedness of a person

A person's QUALIFICATION also affects the results of current exposure: a person who is far from electrical engineering, in the event of being energized, is, as a rule, in more difficult conditions than an experienced electrician. The point here is not in the "habit" to the electric current, because no training produces immunity to the electric current in the body, but in experience, the ability to correctly assess the degree of the danger that has arisen and apply rational methods of freeing oneself from the action of the current.
Taking into account the indicated circumstances, the domestic Safety Rules provide for a mandatory medical examination of personnel servicing operating electrical installations, both upon admission to work and periodically once every 2 years. True, this examination also has another goal - to prevent people with disabilities from servicing electrical installations that may interfere with their production work or cause erroneous actions that are dangerous for others (failure to distinguish a color signal due to visual impairment, the inability to issue a clear command from -for a sore throat or stuttering, etc.).
In addition, in accordance with the legislation on labor protection for adolescents, the Rules allow only adult people (not younger than 18 years of age) who have certain, corresponding to the volume and conditions of the work they perform, to be allowed to service existing electrical installations.

The victim must be quickly released from the effects of current.
If breathing and pulse are stable, then the victim should be comfortably laid down, unbuttoned clothes, removed the belt; it is necessary to ensure complete rest and access fresh air. Breathing and pulse should be monitored continuously; give a sniff ammonia, sprinkle with water.
If the victim does not breathe or breathes convulsively with sobs, then it is necessary to give him artificial respiration.
In the absence of a pulse in the victim, simultaneously with artificial respiration, it is necessary to carry out a closed (indirect) heart massage.
In all cases, call a doctor immediately.
Involuntary convulsive contraction of the muscles of the hand is so strong that it is almost impossible to release the current-carrying part of the victim's hands. Therefore, it is necessary to quickly turn off the electrical installation. If this is not possible, then the victim should be separated from the live part. It should be remembered that touching a person who has become energized can be dangerous to the rescuer himself. Therefore, you can not touch his body with bare hands.
To separate the victim who has fallen under the usual mains voltage (220/380 V), you should use a dry rope, a stick, pull it off with clothes, isolate your own hands with dielectric gloves, a scarf, rubberized cloth, stand on a dry board. It is allowed to cut or cut the wires with a tool with a dry wooden handle.
To release the victim, who has come under a voltage of 1000 V., you should only put on dielectric gloves and boots, pull back with a barbell or tongs designed to voltage this installation.

Artificial respiration

Artificial respiration "mouth to mouth", "mouth to nose".
Artificial respiration consists in the fact that the caregiver exhales air (more than 1 liter) from his lungs into the lungs of the victim. This air contains enough oxygen to revive.
Before starting artificial respiration, it is necessary to prepare the airways. If the victim's mouth is clenched, it should be opened by pushing lower jaw, or insert a flat object between the molars and use it to open the jaws. Then the mouth of the victim is quickly opened and cleared of mucus, the removable jaws are removed. Then the victim's head is thrown back, one hand is placed under the neck, and the other is placed on the forehead. The nostrils are clamped with the thumb and forefinger, then, inhaling deeply, they press their mouth to the open mouth of the victim directly or through a handkerchief and exhale sharply. In this case, the chest (and not the stomach) of the victim should rise. Exhalation will occur spontaneously due to the collapse of the chest. Do 10-12 breaths per minute.
During artificial respiration, it is necessary to monitor the face of the victim: if he moves his lips, eyelids, makes a respiratory movement, you need to check if he himself begins to breathe evenly. In this case, artificial respiration should be suspended. If it turns out that the victim is not breathing, then artificial respiration is immediately resumed.
In the mouth-to-nose method, air is blown in through the nose while the mouth is tightly closed. This method is used if the jaws are clenched so that they cannot be opened.

Indirect cardiac massage

To restore the work of the heart and blood circulation, an indirect heart massage is performed. The victim is placed on a rigid base (floor, bench), freed from restrictive clothing. The caregiver stands on the left side of the victim and puts on lower part his chest with the palm of an outstretched hand, and the second is placed on the first. It is important to correctly determine the place of pressure - two fingers above the end of the sternum. Catch on the sternum should be a quick push of such force as to displace it by 4-5 cm with a frequency of one pressure per second. If assistance is provided by one person, then 2-3 blows and 14-15 pressures are given, if there are two, then 4-6 pressures are done for one blow in 2 seconds. It is recommended to entrust the heart massage procedure to a specially trained worker.
With proper assistance, the victim shows the following signs of recovery: the face turns pink, steady spontaneous breathing appears, pupils constrict. Narrow pupils indicate sufficient oxygen supply to the brain.
A prolonged absence of a pulse with spontaneous breathing and narrow pupils indicates cardiac fibrillation. In these cases, it is necessary to revive the victim continuously both before and after bringing him to the hospital. medical institution or before the arrival of the doctor. Even short-term (less than 1 min.) interruption of rescue assistance can have undesirable consequences.
When the first signs of revival appear, external massage and artificial respiration should be continued for another 5-10 minutes, timing the breath to the moment of one's own inspiration.

The effect of electric current on the human body. Factors affecting the risk of electric shock.

Passing through the body, the electric current produces 3 types of effects: thermal, electrolytic and biological.

thermal the action is manifested in burns of external and internal parts of the body, heating of blood vessels and blood, etc., which causes serious functional disorders in them.

electrolytic- in the decomposition of blood and other organic fluids, thereby causing significant violations of their physical and chemical compositions and fabric in general.

biological the action is expressed in irritation and excitation of the living tissues of the body, which may be accompanied by involuntary convulsive muscle contractions, including the muscles of the heart and lungs. This can lead to various disorders in the body, including mechanical damage tissues, as well as disruption and even complete cessation of the activity of the respiratory and circulatory organs.

There are two main types of damage to the body: electrical trauma and electrical shock.

electrical injury- these are clearly expressed local violations of the integrity of body tissues caused by exposure to electric current or an electric arc. Usually these are superficial injuries, that is, lesions of the skin, and sometimes other soft tissues, as well as ligaments and bones. Electrical burn- the most common electrical injury: burns occur in most victims of electric current 3 kind burns: current, or contact, arising from the passage of current directly through the human body; arc, due to the impact on the human body of an electric arc, but without the passage of current through the human body; mixed, resulting from the action of both of these factors simultaneously, that is, the action of an electric arc and the passage of current through the human body.

electric shock- this is the excitation of living tissues by an electric current passing through the body, accompanied by involuntary convulsive muscle contractions. Depending on the outcome of the negative impact of current on the body, electric shocks can be conditionally divided into the following four degrees:

1) convulsive muscle contraction without loss of consciousness;

2) convulsive muscle contraction with loss of consciousness, but with preserved breathing and heart function;

3) loss of consciousness and impaired cardiac activity or respiration (or both);

4) clinical death, that is, the absence of breathing and blood circulation.

Prevention of electrical injuries consists in observing the established rules and safety measures during operation, installation and repair

electrical installations. In order to prevent chronic electrical injury that may occur as a result of a long stay in electric fields generated near sufficiently powerful generators of high and ultrahigh frequency, shielding of generators, special protective suits and systematic medical monitoring of those working in these conditions are used.

Risk factors for the body: muscle cramps, people can not unclench their hands; fibrillation (heart muscles chaotically contract. At 50 Hz - cardiac arrest), the effect on the brain. Risk factors: lower atmospheric pressure, closed rooms due to low oxygen partial pressure.

Factors affecting the severity of electric shock:

Exposure to electrical current can cause extremely dangerous heart rhythm disturbances, ventricular fibrillation, respiratory arrest, burns, and death. The severity of the injury depends on:

current strength; tissue resistance to the passage of electric current; type of current (alternating, direct); current frequency and duration of exposure.