Various types of electrical injuries. Electric shock. What is an electrical injury? Help with electric shock, consequences and protection against electric shock. What types of electrical injuries are there?

The problem of electrical injury, with the exception of lightning injuries, has become relevant relatively recently. Today, the constant increase in the number of sources of electricity associated with the development of scientific and technological progress certainly increases the level of comfort of life, but at the same time causes a high incidence of electrical injuries and electrical burns.

Despite the fact that electricity has firmly entered the life of mankind relatively recently, the history of electric shocks from artificial sources has been studied for a long time. The first report of death due to electric shock of a carpenter from an alternator appeared in 1879 in Lyon, France.

The first electrocution death in the United States was the death of Samuel Smith from an alternator in Buffalo. Since the event occurred in the presence of many witnesses, and the death of the victim was regarded as quick and painless, it was proposed to use electric current as a “humane” means of execution. The first criminal executed using this method was William Kemmeler, who was sentenced to death in New York State in 1890.

The incidence of electric shock in developed countries is 2-3 cases per 100,000 population. Electrical burns make up 2-3% of burns from other causes, but, despite their relatively modest location, they often cause disability and, in some cases, death, which puts them in first place in importance.

People of young and working age most often suffer from electrical injuries. Men die from electrical injuries almost 4 times more often than women.

Pathogenesis

The pathogenesis of electric shock is not completely clear, since it is almost impossible to study the processes occurring in living tissues at the moment an electric current passes through them.

The abnormal flow of electrons through the body during an electrical shock causes damage or death to the body by depolarization cell membranes nerves and muscles, causing the occurrence of pathological electrical rhythms in the heart and central nervous system, leading to external and internal electrical burns due to heating and evaporation of cell membranes.

The passage of electric current through the brain leads to loss of consciousness and seizures due to the occurrence of foci of pathological depolarization of neuronal membranes. In severe cases, such depolarization leads to respiratory paralysis, which is one of the causes of death from electric shock.

An alternating current shock as it passes through the heart can cause fibrillation.

If the victim is exposed to continuous current for some time, disruption of oxygen transport due to respiratory failure and spasm of vascular smooth muscles can lead to ischemic damage to the brain and internal organs.

Electric current has thermal, electrochemical and biological effects on humans. Electrical energy, passing through the tissues of the body, encounters resistance along the way and, according to Joule's law, turns into thermal energy.

Electrochemical changes under the influence of current lead to aggregation of platelets and leukocytes, movement of intra- and extracellular ions, polarization of proteins, formation of gas and steam, giving tissues a cellular appearance, etc.

The biological effect is manifested by disturbances in cardiac conduction, disruption of the nervous system, contraction of skeletal muscles, etc.

Electrical burns themselves are formed as a result of the conversion of electrical energy into thermal energy in the victim’s tissues. Electrical burns occur mainly at the points of current entry (from an electrical source) and its exit (to the ground), in places of greatest resistance, forming burn surfaces of varying areas and depths, most often in the form of so-called marks, or current signs.

Electrical energy, turning into heat, coagulates and destroys tissue. However, the specificity of the manifestation of electrical burns is determined not only by the depth of the coagulative necrosis itself, but also by the damage to the tissues surrounding the burn and the general changes that occur as a result of the passage of electricity. It should be remembered that electric current damages tissue not only at the site of its application, but throughout the entire path.

The severity and nature of electrical injury are mainly determined by the following factors: the type, strength and voltage of the current, the path through which it passes through the body, the duration of its action and tissue resistance.

It is known that direct current is less dangerous than alternating current. The effect of alternating current on the body depends on its frequency. Thus, low-frequency currents (50-60 Hz) are more dangerous than high-frequency ones.

However, the strength and voltage of the electric current are of greatest importance. The threshold for perceiving the strength of direct current entering the body is 5-10 milliamps (mA), the threshold for perceiving alternating current (60 Hz) used in everyday life is 1-10 mA.

With a current of 10-15 mA, a person cannot take his hands off the electrical wires. A current of 0.05-0.1 ampere (A) is considered fatal, although in some cases death can occur even with less force.

There are low and high voltage electric shocks, as well as atmospheric electricity (lightning). Low voltage is considered to be up to 1000 volts, high voltage is more than 1000 volts.

It should be noted that high voltage electric shock can occur without direct contact with a source of electricity as a result of the action of step voltage or a voltaic arc.

Under the term " step voltage"understand the voltage difference between two points on the ground located at a step distance (usually 0.8 m). It occurs as a result of electrification of the earth by a conductor with a high current voltage that accidentally fell or was laid in the ground, or it can be observed when a discharge of atmospheric electricity (lightning) enters the ground.

Under the term " voltaic arc“understand the movement of an electric charge through the air at a distance of several centimeters to a meter from a current source with a high voltage of several kilovolts. The resulting local burns are limited, but spreading to great depths. The occurrence of arc contact is facilitated by increased air humidity.

Low-voltage burns are predominantly domestic. Low voltage electrical current usually follows the path of least resistance, that is, through tissues that have low resistance, which are arranged in the order described below.

High-voltage burns more often occur in production (during installation of devices, during contact with high-voltage lines, etc.), as a rule, they are more severe, often combined with mechanical trauma and flame burns from burning clothing and nearby objects.

High voltage current travels along the shortest path, causing much more severe damage. Burn disease often develops. Associated and combined lesions are characteristic great vessels with necrosis of muscle masses, damage to internal organs. General action current on the body is observed in most patients. Lethal outcomes, as a rule, arise precisely as a result of high-voltage injuries.

Along with the power and voltage great importance has a path of its passage from the entry point to the exit point. The path of current through the body is called current loop. The most dangerous option is considered to be the so-called. a complete loop (two arms - two legs), in this case the current inevitably passes through the heart, which can cause a disruption in its functioning, even to the point of stopping.

Passage of electric current through in different ways somewhat conditionally. Even with the same loop, the current in the body can move through a number of parallel conductors with different resistances and branches according to Kirchhoff's law.

The resistance of different tissues varies significantly and is related to the specific gravity of the liquid present in them. Thus, the nervous system, blood, mucous membranes and muscles have the least resistance. Dry skin has average resistance. High resistance is characteristic of cartilage tissue, bones and adipose tissue.

It should be noted that resistance may vary depending on objective circumstances. Thus, dry and thick skin of people engaged in manual labor has significantly greater resistance compared to wet and thin skin.

The duration of contact of the victim with the source of electricity is essential. Thus, when exposed to high voltage current, the victim can be immediately thrown off due to a sharp muscle contraction. However, at a lower voltage, muscle spasm can cause prolonged grip of the conductor with the hands. The longer the current, the greater the severity of the injury and the higher the likelihood of death.

Along with the characteristics of the electricity itself, there are several other factors to consider. Thus, in damp and damp rooms (baths, bathrooms, dugouts, etc.) the conductivity of electricity increases significantly. The outcome of electrical injuries, at the same time, largely depends on the state of the body at the time of injury and the age of the victim.

Clinical picture

The clinical picture is very diverse and largely depends on the severity and characteristics of the electrical injury itself. The current, passing through various organs and tissues, causes a number of serious disorders.

To classify the severity of electrical injuries, the scale proposed by G.L. is usually used. Frenkel, as well as the classification of S.A. Polishchuk and S.Ya. Fistal.

G.L. Frenkel proposes to classify the severity of electrical injury as follows:

I degree - partial convulsions;
II degree - general convulsion, which does not entail a state of prostration after turning off the current;
III degree - severe prostration and inability to move for some time even after the current is turned off, with or without loss of consciousness;
IV degree - instant death or death with previous prostration.

Mild electrical injury - convulsive muscle contraction without loss of consciousness.
Moderate electrical injury - convulsive muscle contraction and loss of consciousness, ECG is normal.
Severe electrical injury - loss of consciousness and impaired cardiac and respiratory activity.
Extremely severe electrical injury - clinical death.

The main causes of death due to electrical injury are considered to be cardiac arrest, most often due to fibrillation, respiratory arrest due to paralysis of the respiratory center, shock, and also due to a combination of these reasons.

Many cases have been described sudden death victims several hours after an electrical injury against the background of apparent well-being. Therefore, any victim of an electric shock must be hospitalized in a specialized hospital, where, if necessary, he can be provided with emergency resuscitation care.

When exposed to high voltage electric current, a deep disorder of the central nervous system may occur with inhibition of the cardiovascular and respiratory systems, called imaginary death or electric lethargy. Clinically, this condition is manifested by imperceptible cardiac and respiratory activity. If in such cases the necessary resuscitation measures are carried out, then most often they lead to success, otherwise, in the absence of adequate assistance, actual death may occur.

In the case of massive electrical trauma, signs of shock may develop, requiring intensive care.

Often noted damage to the nervous system, circulatory and respiratory disorders, electrical burns of varying degrees of extent occur.

An electric current passing through the structures of the nervous system leads to disruption of its functions, sometimes leaving behind severe damage in the form of bleeding, swelling, etc. Loss of consciousness of varying duration and degree may occur, followed by retrograde amnesia, convulsions, dizziness, and headache.

In some cases, symptoms of increased intracranial pressure are observed (photophobia, stiff neck, Kernig's sign, epileptiform seizures, etc.). More or less persistent paresis or paralysis of the nerves with motor, sensory and trophic disorders are common.

There may be a disorder of thermoregulation with temperature asymmetry in different areas of the body, the disappearance of physiological reflexes and the appearance of pathological ones, etc. In milder cases, clinical manifestations are limited to flickering in the eyes, weakness, weakness, etc.

Among organic injuries, spinal atrophic diseases associated with electric shock are considered typical. spinal cord in the area of the anterior horns of the brain and gray matter in the circumference of the central canal, manifested by trophic and vasomotor disorders in the innervated areas.

Violations by of cardio-vascular system , as a rule, are more functional in nature and are often expressed in the form of various cardiac arrhythmias ( sinus arrhythmia, tachycardia and bradycardia, extrasystole, heart block phenomena). The most severe disorder is ventricular fibrillation and cardiac arrest.

Prolonged vascular spasm, as already mentioned, can lead to ischemic damage to the central nervous system, limbs and internal organs. Long-term spasm of the vessels of the extremities is clinically characterized by their cyanosis, swelling, coldness and absence of pulse in the main vessels.

Effect of current on striated and smooth muscles leads to its spasm, which can be expressed by cramps of skeletal muscles, spasm of the muscular layer of blood vessels with increased blood pressure, coronary spasm. Damage to the walls of blood vessels by current in some cases leads to subsequent arrosive bleeding.

Significant contraction of skeletal muscles when injured by high voltage current or atmospheric electricity can lead to fractures of the spine and long tubular bones.

The predominance of the phenomena of evaporation and necrosis in the striated muscles leads to its swelling with pinching in the fascial sheaths, which requires urgent surgical correction. In addition, muscle swelling causes or aggravates compression of the neurovascular bundles of the extremities with aggravation of the phenomena of edema and ischemia.

Due to exposure to bright light, which occurs, for example, during a voltaic arc, vision can be affected, which manifests itself in the form of keratitis, choroiditis with the subsequent development of cataracts, which is observed in approximately 6% of cases of high voltage current injury. Retinal detachment and hyphema may also occur.

Damage to the sensory organs is possible, which is manifested by tinnitus, decreased hearing, and a disorder of touch. When exposed to high voltage current or lightning, ruptured eardrums, middle ear injuries with the development of hematotympanum, otoliquorhea and subsequent deafness can occur.

Sometimes traumatic emphysema and pulmonary edema occur, and in case of high voltage electric shock - bruises and ruptures of the lungs, functional liver failure, glomerulonephritis, transient enteritis. Cases of damage to the stomach, pancreas, and gallbladder have been described.

In places of greatest resistance to current - input and output - due to the transition of electrical energy into thermal energy, burns are formed, up to charring of limbs and parts of the body in severe lesions, or most often in the form of electric marks, or signs of current, which are areas of dry necrosis.

The shape of electric tags is round or oval, but can also be linear; the color is usually lighter than the surrounding skin - grayish-white or pale yellow. Often there is a ridge-like elevation along the edges of the affected skin, as a result of which the middle of the mark appears somewhat sunken.

A characteristic feature of electrotags is their complete painlessness due to damage to the nerve endings. Sometimes there is detachment of the epidermis in the form of blisters, but, unlike thermal burns, without liquid contents. The hair in the area of the electrical marks, while maintaining its structure, twists in a spiral.

A characteristic phenomenon is metallization - deposits of conductor metal particles in the skin (yellow-brown color - iron, blue-green color - copper, etc.). In low voltage electrical trauma they are located on the surface, while in high voltage they spread deep into the skin. As a result, details of the conductor configuration can be displayed in the contact area.

Exit cues tend to be more pronounced than entry cues. In places of bends, the current, passing along a shorter path, can exit the body and re-enter, leaving stage electrical marks.

It should be noted that electrical burns are often not limited to signs of current on the skin. They are characterized by a deeper spread with primary necrosis of deeper tissues - muscles, tendons, joints, bones, etc., which determines the real severity of the damage to patients.

Often, foci of necrosis are located under apparently healthy skin. With massive muscle damage and release of myoglobin, a syndrome similar to crash syndrome may develop.

In some cases, when exposed to high voltage current, so-called “pearl beads” can form in the bones, which are the result of melting and subsequent solidification of calcium phosphate in the form of round white formations with a diameter of 1-2 mm.

Subsequent secondary expansion of necrosis zones due to thrombosis and partial death of blood vessels after exposure to electric current is possible, which makes it difficult to early determine the entire volume of the lesion. The rejection of dry scab occurs slowly. Arrosive bleeding during demarcation is not uncommon.

Secondary damage during electrical trauma, not directly related to the action of current, most often are thermal burns from flaming objects, mechanical injuries as a result of a fall from a height, being thrown away from a source of electricity, etc., which can significantly aggravate the general condition of the victims.

The clinical course of electrical burns is in many ways similar to the course of thermal burns. With extensive lesions, including deep-lying tissues (muscles, bones, etc.), there is a high probability of developing a burn disease.

Has some features clinical picture lightning damage. There is a higher mortality rate, which is usually 70-90%, and frequent loss of consciousness. At contact points, lightning causes deep charring of tissue and sometimes skin tears. Characteristic is the symmetry of the lesions when an electric discharge passes from the head to both legs and the predominant damage to the lower part of the body from the step voltage that occurs when a lightning strike near the victim.

It should be noted that the clinical manifestations of electrical injury, depending on its specific characteristics, can vary significantly - from mild injuries to extremely severe conditions, leading in some cases to the death of victims.

Treatment

The final outcome of an electrical injury largely depends on the provision of quick and adequate first aid.

First of all, if the victim is under the influence of electric current, this exposure must be stopped, observing established safety rules. If possible, it is necessary to open electrical circuit using a circuit breaker or switch, or by unplugging the plug from the electrical outlet.

If for some reason this cannot be done, then you need to remove the current source from the victim using insulating objects, for example, a dry wooden stick, clothing, rope, leather or rubber gloves, etc.

To isolate the rescuer himself, you can also use insulating objects - dry boards, rubber, car tires, etc. When releasing a victim from a source above 1000 volts, special safety measures should be taken.

After the victim is freed from the current, first aid begins. It is important to immediately correctly assess the state of cardiac and respiratory activity. If necessary, resuscitation measures are started according to the ABC algorithm - closed heart massage, artificial ventilation (mouth-to-mouth breathing, etc.).

An emergency medical team arriving at the scene of an injury must quickly assess the situation and determine the priority of resuscitation measures. If there are signs clinical death, you must start (or continue) immediately indirect massage heart and artificial ventilation of the lungs with a breathing apparatus through a mask, and if ineffective, perform tracheal intubation.

If these measures are unsuccessful, within 2-3 minutes it is necessary to inject intracardially 1 ml of a 0.1% solution of adrenaline and 10 ml of a 10% solution of calcium chloride, intravenously (i.v.) - 1 ml of a 0.05% solution of strophanthin, diluted in 20 ml of 40% glucose solution, or perform electrical defibrillation of the heart.

Victims with signs of shock are transported to a medical facility only in a lying position with constant monitoring of cardiac activity. Evacuation of such patients, if it lasts more than 20-25 minutes, should be accompanied by anti-shock measures along the route: oxygen inhalation, intravenous administration of colloidal plasma-substituting and electrolyte solutions (reopolyglucin, hemodez, lactasol, etc.), the use of cardiotonic, antihistamine, antispasmodics, analgesics, etc.

In the hospital after admission emergency measures to stabilize cardiac and respiratory activity, collect anamnesis, find out the conditions of the injury, carry out general examination(chest x-ray and abdominal cavity, ECG, computed tomography of the head, as well as the chest and abdominal cavity if indicated) to exclude possible combined trauma (fractures, blunt trauma, etc.).

Principles of intensive care for electrical trauma, burn shock and local treatment electrical injuries at all stages of medical care are the same.

Before transportation, dry gauze or contour bandages are applied to the burned surfaces. The application of ointment dressings is contraindicated.

Patients with deep electrical burns, electrothermal injuries of any location should be provided with specialized treatment in possible early dates.

All victims with symptoms of shock are subject to hospitalization in the department or wards of resuscitation and intensive care. Patients with limited electrical burns without signs of electrical or burn shock are hospitalized in the general wards of a surgical hospital.

Victims without local lesions, even in satisfactory condition, are hospitalized for 2-3 days in the general medical department for observation and examination. They are given local conservative treatment: toilet of burn wounds, according to indications - dressings.

Patients with electrical injuries are also treated here. According to indications, they are administered cardiac and antiarrhythmic drugs, vitamins, and other symptomatic remedies(korglykon, ATP, cocarboxylase, nitroglycerin, aminophylline, lidocaine, vitamin C, etc.).

Transfusion antishock therapy for electrical trauma should be aimed at normalizing central and peripheral hemodynamics. It is advisable to begin such therapy with the introduction of balanced electrolyte solutions to correct rapidly developing water-salt disorders in various water sectors of the body.

After this, colloidal plasma substitutes are administered, and isogenic protein preparations are used, as a rule, no earlier than 8-12 hours after the lesion. The volume of infusion therapy on the first day of shock ranges from 30 to 80 ml/kg of the victim’s body weight (depending on the severity of shock) under the control of hourly urine output (optimally 1.5-2.0 ml/kg of body weight).

The amount of administered transfusion agents in the next two days is reduced by 25-35%. The complex of transfusion therapy for electrical trauma must include relatively large quantity 10% glucose (100-150 ml/s).

Direct anticoagulants (heparin) and antiplatelet agents (trental, chirantil, troxevasin), drugs that improve the metabolism of the heart muscle are also prescribed; according to indications, antihistamines and corticosteroids, analgesics, antispasmodics, α-blockers, vitamins, osmodiuretics and saluretics are used.

To treat or prevent arrhythmia, the administration of antiarrhythmic drugs is indicated (isoptin 0.25% 2 ml intramuscularly, lidocaine 10% 2 ml intramuscularly). The use of sodium bicarbonate and proteolysis inhibitors (Gordox, Contrical, etc.) is essential.

When lesions are localized in the head area, especially with prolonged loss of consciousness, increased dehydration therapy with loop or osmotic diuretics (Lasix, mannitol) is required.

For lesions of the extremities as urgent action Intra-arterial (worse - intravenous) administration of antispasmodics is indicated (papaverine 2% 2 ml, a nicotinic acid 0.1% 1 ml with novocaine 0.5-1% 10 ml) and heparin 5-10 thousand units. Daily dose heparin should not exceed 20-30 thousand units.

Along with early intensive transfusion therapy and other medications, victims with electrical trauma require urgent active surgical interventions - necrotomy, dissection of the fascia, opening and drainage throughout the muscle masses of the affected limb segments. For circular deep lesions, decompressive necrotomy is necessary in the first hours after injury, including in a state of burn shock.

Any suspicion of great vessel injury is an indication for fasciotomy to the proximal level of muscle necrosis. Fasciotomy is indicated for subfascial edema and an increase in volume of a limb segment, absence or weakening of pulsation of the great vessels, and discoloration skin limb segment (pallor, cyanosis, marbling), decreased or absent tactile or pain sensitivity. Required condition is a dissection of the fascia over each muscle group.

Decompressive necrotomy, fasciomyotomy, intra-arterial administration of antispasmodics and heparin are effective in the first 6-12 hours after injury. Carrying out these activities later than 24 hours often turns out to be late, and after 36-48 hours - ineffective.

In case of arrosive bleeding, already in the Central District Hospital or Central City Hospital, ligation of the vessels should be carried out throughout.

In case of combined lesions with the presence of bruised wounds, open fractures, dislocations, primary surgical treatment of wounds, osteosynthesis, hardware stabilization are carried out after anti-shock measures.

Local treatment begins with primary processing burnt surfaces. Urgent emergencies are performed first surgical interventions(decompressive incisions, ligation of blood vessels, amputations).

In case of deep necrosis causing compression of soft tissues, decompressive incisions in the form of necrotomies, fasciotomies, and myofasciotomies are performed as early as possible. Such incisions reduce compression of the neurovascular bundle, prevent secondary ischemic necrosis and at the same time are an informative diagnostic technique that determines the depth of necrosis.

In case of arrosive bleeding, ligation of the vessels is performed throughout.

The significant depth of necrosis in electrical burns often requires resolving the issue of amputation (in 10-15% of cases). The indication for amputation is total necrosis of the soft tissues of the extremities or their segments, involving joints, great vessels and nerve trunks. Delay in amputation in such cases is fraught with the development of gangrene, acute renal failure, sepsis and patient death.

As a rule, wounds after amputation are left open to monitor further progress. wound process. If the course is favorable, the wounds are closed using skin grafting. The formation of a stump for wearing a prosthesis is usually done during the rehabilitation period.

Surgical treatment, osteosynthesis and other necessary surgical interventions for combined injury with the presence of mechanical wounds, open fractures, etc. usually performed after anti-shock measures and stabilization general condition patient.

Surgical and chemical necrectomies remain one of the main methods of local treatment of electrical burns. Difficulty early detection the entire depth of tissue damage determines the relative frequency of staged necrectomies. Their implementation allows not only to prevent the development of purulent-inflammatory complications, but also to significantly speed up the preparation of wounds for plastic closure.

Prepared wounds are closed, as a rule, using autodermoplasty or, in cases of exposure of deep-lying structures - bones, joints, nerves, etc., plastic surgery with fasciocutaneous or musculocutaneous flaps on a feeding pedicle.

Convalescents who have suffered electrical trauma often require long-term rehabilitation, since the effect of electric current can cause complications in the long term. Such complications include damage to the central and peripheral nervous system (encephalopathy, paresis, neuritis, trophic ulcers), the cardiovascular system (dystrophic changes in the myocardium, rhythm and conduction disorders), cataracts, hearing impairment, as well as dysfunction of other organs and systems.

Repeated exposure to electricity can lead to early arteriosclerosis, obliterating endarteritis, and persistent vegetative changes. In addition, electrical burns often heal with the formation of deformities and contractures, requiring reconstructive operations.

Thus, emergency care and subsequent staged treatment of electrical injury, taking into account its severity, require intensive anti-shock measures, as well as compensation for breathing and cardiac activity, while simultaneously actively managing local injuries, including emergency surgical interventions.

Treatment of electrical injuries characterized by extreme diversity clinical manifestations and structural and functional disorders, of course, is a multidisciplinary task and requires close attention from doctors of various specialties.

The variety of influences of electric current on the human body leads to electrical injuries, which are conventionally divided into two types:

Local electrical injuries that cause local damage
body;

General electrical injuries (electrical shocks) when affected
(or there is a threat of damage) the entire body due to a violation
normal activity vital important organs and systems.

According to statistical data, the distribution of accidents due to electric current in industry by type of injury is as follows:

Local electrical injuries - 20%;

Electric shocks - 25%;

Mixed injuries (simultaneously local electrical
injuries and electrical shocks) - 55%.

Local electrical trauma- a pronounced violation of the integrity of body tissues, including bones, caused by the influence of electric current or electric arc. Most often these are superficial injuries, that is, damage to the skin, and sometimes to other soft tissues, ligaments and bones. Local electrical injuries are cured and the victim’s performance is restored fully or partially. However, with severe burns the person dies. In this case, the direct cause of death is not the electric current, but local damage to the body caused by the current. Typical local electrical injuries: electrical burns, electrical marks, skin metallization, mechanical damage and electroophthalmia.

Approximately 75% of cases of electric shock to people are accompanied by local electrical injuries.

By type of injury, these cases are distributed as follows, %:

Electrical burns - 40;

Electrical signs - 7;

Metallization of skin - 3;

Mechanical damage - 0.5;

Electroophthalmia - 1.5;

Mixed injuries - 23;

Total - 75.

Electrical burns- this is damage to the surface of the body under the influence of an electric arc or large currents that pass through the human body.

Electric sign- this is a clearly defined mark with a diameter of 1-5 mm of gray or pale yellow color, which appears on

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the surface of human skin where the current passes. In most cases, electrical signs are painless (the top layer of skin comes off, and the affected area returns to its original color, plasticity and sensitivity are restored).

Electrometalization- penetration of metal particles into the skin due to its splashing and evaporation under the influence of current. It can occur during short circuits, power outages by disconnectors and switches under load. In this case, small particles of molten metal, under the influence of dynamic forces and heat flow, scatter in all directions at high speed. Each of these particles has a high temperature with a small reserve of heat and therefore is not capable of burning through clothing. Therefore, exposed parts of the body are affected: hands and face.

If the eyes are damaged, treatment can be lengthy and difficult, and in some cases the victim may lose vision. Therefore, work that may result in an electric arc should be performed with safety glasses.

Mechanical damage is in most cases the result of sudden convulsive muscle contractions under the influence of current that passes through the human body.

As a result, ruptures of tendons, skin, blood vessels and nervous tissue and even bone fractures. Mechanical damage occurs when working in installations with voltages up to 1000 V when a person remains under voltage for a long time. The degree of electric shock to a person is significantly influenced by the type and magnitude of the current, the duration of its action, and the path of the current through the human body.

Electroophthalmia is an inflammation of the outer membranes of the eyes, which occurs under the influence of a powerful stream of ultraviolet rays. Such irradiation is possible when an electric arc forms (during a short circuit).

Electroophthalmia develops 4-8 hours after ultraviolet irradiation. In this case, redness and inflammation of the skin, mucous membranes of the eyelids, tears, purulent discharge from the eyes, eyelid spasms and partial loss of vision. The victim feels headache And sharp pain in the eyes, which intensifies in the light.

Prevention of electroophthalmia when servicing electrical installations is ensured by the use of safety glasses with regular glass, which almost do not transmit ultraviolet rays

and at the same time protect the eyes from infrared radiation and splashes of molten metal.

Electric shock- this is the stimulation of living tissues of the body by electric current, which is accompanied by convulsive muscle contractions. Such a blow can lead to disruption and even complete cessation of the functioning of the lungs and heart. At the same time, a person may not have external local damage, that is, electrical injuries.

Depending on the severity of the damage, electric shocks can be divided into 5 degrees:

I - convulsive, barely perceptible muscle contractions; II - convulsive muscle contractions, which are accompanied by severe, barely bearable pain without loss of consciousness;

III - convulsive muscle contractions with loss of consciousness, but
while maintaining breathing and heart function;

IV - loss of consciousness and disturbance of cardiac activity or breathing;

V - clinical death, that is, stoppage of the heart and lungs.

3.4.3. CAUSES OF FATALITY FROM ELECTRIC CURRENT

Causes of death from electric current can be: cessation of cardiac function, respiratory arrest and electric shock. It is also possible that two or even three of these reasons operate simultaneously. Cessation of cardiac activity from electric current is the most dangerous, since bringing the victim back to life in this case is, as a rule, a more difficult task than in case of respiratory arrest or shock. The effect of current on the heart muscle can be direct, when the current passes directly to the heart, and reflexive, that is, through the central nervous system, when the current path lies outside this region.

In both cases, cardiac arrest or fibrillation may occur. In case of electric shock, cardiac fibrillation occurs much more often than complete cardiac arrest.

Cardiac fibrillation ■- chaotic multi-temporal contractions of cardiac muscle fibers (fibrils), in which the heart is unable to drive blood through the vessels. Heart fibrillation can occur as a result of passing through the human body along the path hand-hand or hand-foot alternating current with a force of more than 50 mA at a frequency of 50 Hz for several seconds.

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In case of cardiac fibrillation, which occurs due to short-term action of current, breathing can continue for 2-3 minutes. Since, along with blood circulation, the supply of oxygen to the body also stops, a person experiences a rapid, sharp deterioration in his general condition and breathing stops. Fibrillation lasts a short time and ends in complete cardiac arrest. Clinical death occurs.

The cessation of breathing occurs due to the direct effect of the current on the muscles chest, which are involved in the breathing process. A person begins to feel difficulty breathing due to convulsive muscle contractions already at a current of 20-25 mA with a frequency of 50 Hz. At higher value current strength, this effect is enhanced. In the case of prolonged passage of current, a person experiences asphyxia - a painful condition due to a lack of oxygen and excess carbon dioxide in the body. With asphyxia, consciousness, sensitivity, and reflexes are gradually lost, then breathing stops, and after some time the heart stops or fibrillation occurs, that is, clinical death occurs. The cessation of cardiac activity in this case is due not only to the direct influence of the current on the heart, but also to the cessation of oxygen supply to the body, including the cells of the heart muscle due to respiratory arrest.

Electric shock- a kind of severe neuro-reflex reaction of the body due to irritation by electric current, which is accompanied by profound disorders of blood circulation, breathing, and metabolism. State of shock lasts from several tens of minutes to a day. After this, the death of a person may occur due to the complete extinction of vital important functions, or recovery - due to timely active medical intervention.

Electrical injury is an injury resulting from a person being struck by electric current or lightning. A potential threat to humans is represented by a current strength of more than 0.15 Amperes, as well as direct and alternating voltages of more than 36 Volts. The consequences of electrical injuries can take a variety of forms - from minor burns to cessation of blood circulation, breathing and loss of consciousness, which, accordingly, often causes death. In almost all cases, the effect of current more than normal accompanied by damage to the skin, mucous membranes and bones at the points of entry and exit of the electrical discharge. The central and peripheral nervous systems are also affected.

Types of electrical injuries

Electrical injuries vary according to the location of their occurrence, the nature of the injury (local and general electrical injuries) and the nature of the impact of electricity.

Depending on the place of occurrence, the following types of electrical injuries are distinguished:

Production;
Household;
Natural.

According to the nature of the electric shock to a person, they are distinguished:

Local electrical injuries - electroophthalmia, burns, metallization of the skin (penetration under the skin and melting of small metal particles under the influence of an electric arc), mechanical integrity violations;
General electrical injuries are electric shock to various muscle groups, accompanied by respiratory and cardiac arrest, as well as convulsions.

Local electrical injuries occur due to the impact of a short circuit on a specific part of the body. General electrical trauma is the result of the direct action of current from the moment it passes through the entire human body. When struck by lightning, along with the symptoms inherent in a general injury, hearing and speech impairment occurs, and dark blue spots appear on the skin.

Depending on the nature of the impact of electric current, there are the following types of electrical injuries:

Instant – receiving an electrical discharge that exceeds the permissible level in a matter of seconds. Such an injury is accompanied by injuries that are dangerous to health and life, so the victim needs urgent resuscitation and surgical care;
Chronic – the effect of electrical voltage on a person is long-term and imperceptible. For example, people who work near high-power generators suffer from chronic electrical injuries. IN in this case the lesion is characterized by sleep and memory disturbances, increased fatigue, tremors, headaches, dilated pupils and increased blood pressure.

Causes of electrical injuries

In most cases, the causes of electrical injuries are direct contact with live elements of electrical installations and work with them without removing the voltage in advance. In this case, the injury rate is 80-90%. Negligence and inattention are the main causes of electrical injuries: unsatisfactory insulation condition, untimely shutdown of current, interruption of voltage supply.

In other words, the causes of electrical injuries can be classified as follows:

Technical – equipment malfunction, improper operation;
Organizational – non-compliance with safety regulations at home and at work;
Psychophysiological – fatigue, inattention caused by various reasons.

The impact of lightning is classified as a separate group as an objective cause.

As a rule, in production, incidents occur most often at the time when workers finish or begin work shift, that is, during shift changes, as well as in the morning. In the first option, the key factor is elementary fatigue, and in the second - the peculiarities of planning the coming working day, since it is in the morning hours that the largest number of works with electrical equipment occurs.

A victim of an electrical discharge needs emergency care, which involves, first of all, turning off the source of damage - de-energizing the device. To do this, you need to press the switch or turn the switch and turn off the plugs.

When providing assistance in case of electrical injury, it is necessary to take precautions: remove wires from the injured person only with insulated tools. Any other items are also suitable for this purpose, but they must be dry. If possible, operations should be performed with rubber gloves. If the wires have not yet been disconnected, it is strictly forbidden to touch the person affected by the current with unprotected hands.

The victim must be placed on a flat surface, doctors must be called as soon as possible and the following steps must be taken to help with an electrical injury:

Check the person’s pulse, and if it is absent, perform an indirect cardiac massage, since the injury has caused circulatory arrest;
Check breathing - if not, perform artificial respiration;
If there is a pulse and breathing, place the victim on his stomach, turning his head to the side. In this position, a person is able to breathe safely, otherwise there is a high probability that he may choke on vomit;
It is very important to free a person from tight clothing, as well as to prevent hypothermia. To do this, you need to cover it with heating pads or cover it with warm, dry clothes (blankets);
If burns occur as a result of an electrical injury, they should be covered with a dry and clean bandage. If the hands and feet are affected, rolled cotton swabs or bandages should be placed between the fingers;
Examine the victim to identify other injuries and provide assistance if any;
If the victim is conscious, give him to drink as much liquid as possible, preferably plain clean water.

Even if a person’s condition after an electrical injury does not show serious symptoms at first, in any case he needs urgent hospitalization, since irreversible disruptions in the body can occur at any time. Timely assistance with a high probability can bring a person back to life even with a strong general electric shock.

Electrical trauma is an injury caused by exposure of organs and tissues to electrical current of great strength or voltage. There are the following types of electrical injuries:

Local: when damaged in a specific location;
Common electrical injuries or electrical shocks: damage occurs throughout the body due to damage and dysfunction of vital systems, which results in the impossibility of their normal functioning.

A fifth of all such cases are local injuries. A quarter of these are electrical shocks accompanied by electrical shock. More than half are mixed: at the same time, symptoms of both local and widespread injuries are present.

Local electrical injuries

Local electrical trauma is a pronounced damage that entails a violation of the integrity of the skin and various types tissues, including bone and connective tissues. This type of injury is caused by electric current or high voltage in an electrical arc. Typically, such injuries result in only minor damage, mainly to the person's skin, as well as other types of soft tissue, tendons and joints.

The consequences of local electrical injuries and the difficulty of dealing with them depend on the location, level of penetration and characteristics of tissue rupture, as well as on how the body reacts to the traumatic impact.

Most often, local electrical injuries are treated with simple treatment, and the patient’s ability to work is restored completely, sometimes partially. The causes of electrical injuries can be very diverse. Lethal outcome as a result of local electrical injuries occurs extremely rarely and only if the damage is accompanied by a large area of the body. Death in such a situation is caused not by current, but by local violation body tissues, which was the result of high voltage damage.

Typical local electrical injuries:

electrical burns - in four cases out of ten;
electrical marks - seven cases out of a hundred;
metallization of the skin: only three out of a hundred people get this complication;
mechanical disorders occur in five cases out of a thousand;
Fifteen people out of a thousand receive this injury, and this injury is the most dangerous;
mixed electrical injuries, including burns, twenty-three people out of a hundred.

Electrical burn is the most common electrical injury. It appears in two thirds of people injured as a result of exposure to high voltage. Moreover, a quarter of cases are accompanied by other traumatic injuries.

More than three-quarters of all electrical burns occur among linemen who maintain high-voltage transmission lines.

Types of electrical burns

There are two types of electrical burns based on the condition of occurrence:

Electrical burn. Appears when electric current flows directly through the human body. Usually develops after contact with a conductive object.
Arc burn. Its cause is the effect of a high voltage arc on the human body.

Electrical burns occur at low voltages of no more than two kilowatts. It occurs in about a third of people who suffer electrical injuries, and in such cases they are considered stage 1 and 2 burns, and at voltages exceeding 380 volts they are assigned stages 3 and 4.

For different stages Burns are characterized by the following symptoms:

Stage 1: pinking of the skin;
Stage 2: the appearance of bubbles;
Stage 3: necrosis of all layers of skin;
Stage 4: soft tissues turn into embers.

An arc burn appears at a voltage of 6 kilowatts or more. Most often this is due to the profession of the victim: electricians who often experience spontaneous short circuits when repairing electrical appliances are at risk.

The arc appears in three cases:

without direct contact between a person and conductive parts - when being close to them at the moment of penetration;
if the integrity of the protective insulation with which the electrician touches the conductive elements is violated;
due to errors during operations with switches, when an arc spontaneously attacks a person who has neglected safety precautions.

The severity of the injury increases with increasing strain. Quarter total number are arc burns that often accompany these types of electrical injuries.

Less common effects

Electrical marks are distinct, dark, gray or yellow patterns on the surface of the skin where an electrical current has been applied. They usually have the shape of irregular circles and are no more than 5 millimeters in size with a dent in the central part. There are marks in the form of abrasions, bruises, and even small-point tattoos, sometimes in the shape of a wire that the patient touched, and when struck by a discharge during a thunderstorm, this mark is made in the form of lightning.

The affected area hardens and becomes like a callus, as necrosis of the upper layer of skin begins. The surface of the mark never contains moisture and does not hurt. But only a tenth of all those affected by electric shock receive such traces. This injury still has no exact explanation.

Metallization of the skin is the penetration of metal elements into the skin, which melt during an arc discharge.

This usually happens due to short circuits in switches. Due to the resulting electrical dynamics, splashes of hot metal scatter at enormous speeds in different directions.

Lesions usually occur on uncovered parts of the body: the head and upper limbs, since these drops cannot burn through clothes. The patient feels pain and the presence of foreign components in the skin.

Gradually, the damaged skin slides off and this area restores its appearance and functionality. Metallization occurs in only ten out of a hundred people.

Mechanical disturbances are usually the result of spontaneous muscle spasms when exposed to current. The result of this is a violation of the integrity of the ligaments, skin, capillaries and nerve nodes, sometimes even joint sprains, dislocations and fractures occur.

Mechanical failures mainly occur when working with voltages not exceeding a thousand volts. The effect of current must be long-lasting. This happens infrequently, in about one person out of a hundred.

A corneal burn is the most dangerous consequence of this type of injury. It occurs due to directed thermal radiation after the formation of an electric spark. It occurs in three people out of a hundred who have received an arc burn.

An electric shock is the irritation of a person's soft tissues by current passing through them. It manifests itself in spontaneous spasms of various muscles of the body. An electric shock is a consequence of the passage of current through the human body: the danger of dysfunction of internal organs covers the entire body. This occurs due to disruption of almost all vital systems, including the heart, kidneys, liver, stomach and even the brain.

Depending on the degree of violation, there are five types of electric shock:

the cramp is almost imperceptible;
muscle spasm accompanied by sharp painful sensations which can lead to loss of consciousness;
the spasm is accompanied by fainting, but breathing is not interrupted and the heart rate remains unchanged;
after fainting, the disturbed heart rhythm is interrupted, and breathing may be absent;
clinical death: not only breathing is interrupted, but also blood circulation.

The result depends on many conditions, such as:

voltage and current;
frequency of electric current and electromagnetic field;
individual characteristics of the body;
skin resistance and electrical potential difference;
compliance with safety precautions and timely treatment.

The level of impact of the current can vary: from barely noticeable muscle contractions near the damaged area to complete stoppage of the functioning of the lungs and heart. It must be remembered that visually after an electrical injury, the skin may not contain traces of electric shock, so in all cases a doctor’s consultation is necessary.

Injury to body tissues most often results from external influences of various types of energy. Damage can be mechanical, chemical, or thermal in origin. The cause of all types of electrical injuries is electric shock, which can be encountered anywhere: at home, at work, in a cafe or just on the street. Most often, the culprit is inept handling of electrical appliances and their faulty condition.

Causes of electrical injuries

Compared to other types of damage, electrical injuries are considered the most dangerous due to the high probability of death. The consequences of electric shock primarily depend on the strength and duration of its impact. In addition, age and health status determine the chances of saving a person who has received any type of electrical injury.

The rules for providing first aid to victims of electric shock have a number of distinctive features that will have a direct connection with the causes of the incident. Thus, electrical injuries are caused by the following factors:

contact with a conductive part that does not have an insulating coating;
interaction with metal that is under tension due to damage to the protective layer;
touching wet objects that have received a charge.

Water as a risk factor for electrical injury

The severity of the resulting electrical injury is determined by the strength of the applied energy. Additional conditions that may influence the intensity of the blow are the thickness of the epidermis and its humidity. Regardless of the type of electrical injury, damage occurs through the passage of current through the human body, and therefore, when providing first aid, great importance is paid to exactly how the discharge passed and how long it affected the tissue.

Water is an ideal conductor for ions, the movement of which serves as the basis for the transfer of electrical charge. If we take into account statistical data, the number of victims of electric shock increases during the period of warming and increasing humidity levels in environment. High air temperatures cause a person to sweat more. Natural phenomena summer also increases the chances of contact with naturally occurring electrical current. Thus, with an increased concentration of electric charge in the air, a thunderstorm occurs. Those who remain outside in bad weather and find shelter under a wet tree are especially at risk of being struck by lightning. There is also a danger of encountering electric current in a room with a humidity level that exceeds the norm.

Main types of electrical injuries

The choice of direction in providing first aid depends on what type of electrical injury occurred to the victim. However, it is worth noting that even with a slight electric shock, damage can affect the functions of the entire body in the future, so you cannot hesitate. All types of electrical injuries are conventionally divided into two categories:

local (local) tissue damage;
complex electric shocks.

Local tissue damage by electric current

The first group of lesions consists of superficial lesions of the skin at the site of passage of the electrical charge. All types of local electrical injuries are manifested by oval, semicircular marks of a gray or yellow hue, metallization of the epidermis as a result of tiny iron particles entering its upper layers.

The occurrence of electrical burns is explained by the passage of current through soft tissue, the strength of which exceeds several amperes. The skin heats up instantly, and therefore the severity and depth of the lesions will depend on the nature and duration of exposure to the charge. Thus, a distinction is made between superficial and internal injuries. Depending on the type of exposure, electric shock can be contact or arc. In addition, mechanical damage that occurs due to convulsive contraction of muscle tissue during the passage of a charge is also a type of electrical injury. Electric current can destroy the integrity of the skin, rupture blood vessels, and lead to dislocations and fractures of bones.

Local damage includes the development of the inflammatory process in eyeball, activated as a result of powerful light exposure. This type Electrical injury is called electroophthalmia.

Effect of electricity on vital centers: degree of damage

Complex electric shocks, in contrast to local damage to soft tissues and bone structures, are systemic lesions that affect the functioning of the body as a whole. The passage of an electrical charge through the human body leads to serious and sometimes irreversible changes in the functioning of internal organs. In accordance with the intensity of exposure to electric current, the following degrees of damage are distinguished:

The first is characterized by the appearance of seizures in the limbs or a separate part of the body. The victim is in creation.
The second degree of electric shock is diagnosed with general convulsive activity and short-term fainting. Heart rate and breathing remain unchanged. If the source of the influencing current is timely eliminated, the victim’s condition will stabilize.
To be classified as third degree, the victim must exhibit symptoms such as loss of consciousness, dysfunction of the cardiovascular system, and respiratory organs.
With the fourth degree of electrical injury, cardiac and respiratory arrest occurs. The rapid development of shock leads to death.

What happens to the body when a charge of energy passes through it?

The pathogenesis and mechanism of damage to the human body by electric charge has been partially studied, since it is almost impossible to study the processes occurring in the body during direct receipt of any type of electrical injury. First aid to the victim must be provided urgently, since the movement of ions and electrons causes cardinal disturbances as a result of changes in the polarity of cell membranes.

Electric current primarily affects the central nervous system due to its high saturation with water. Abnormal phenomena lead to disruption heart rate, activity of the nervous system.

With an extremely severe degree of damage, depolarization can provoke the onset of clinical death. Hypoxia as a consequence of respiratory arrest leads to spasms of cerebral vessels and ischemic damage to other organs and systems. Pathological disorders that occur in the first few hours after the incident are called early symptoms, and those changes that occurred after this period are late.

Electrical shock to the head

The most dangerous electrical injury can be considered damage that occurs as a result of the passage of an electrical charge through the head. Closing the brain-limb loop inevitably leads to instant death caused by damage to all vital systems and centers simultaneously. Cases of so-called imaginary death can also be called frequent: the victim loses consciousness while long time, while his breathing becomes rare and barely noticeable, the pulse cannot be felt, and heartbeats cannot be heard.

How to help the victim?

When providing first aid to a victim in case of electrical injury, it is important to follow the sequence of actions and not give in to panic. Every second counts, so when you detect a person under the influence of electric current, you must:

Quickly eliminate the consequences of an electric charge - unplug the electrical appliance from the socket, turn off the supply of electricity to the room, move the wire, etc.
It is extremely important that all actions are performed using dry, non-conductive objects (wooden stick, fabric rope, etc.). Ideally, the person providing assistance to the victim should be wearing rubber gloves and boots.
If the victim has been exposed to an electric current of more than 1000 V, it is important to immediately begin resuscitation measures to restore respiratory function and heartbeat. The heart muscle is massaged and artificial respiration mouth to nose or mouth to mouth.
In case of a sudden decrease in blood pressure, drugs should be administered parenterally to help stabilize it.
If fractures, ligament ruptures, or damage to osteochondral areas are suspected, a splint should be applied or the affected limb should be immobilized with available means until doctors arrive.

Professional medical assistance to the victim

Upon arrival of the ambulance team, a complex of resuscitation actions is carried out, and artificial lung ventilation drugs are connected. If closed cardiac massage is ineffective, a solution of calcium chloride and adrenaline is administered intracardially to the patient, or an electrodefibrillation procedure is performed. Transportation of victims is carried out strictly in a supine position with continuous monitoring of heart function. No later than 30 minutes after the victim has regained consciousness, emergency doctors must provide the necessary anti-shock treatment. Further therapy is carried out within the walls of a hospital medical facility under the supervision of specialists. After the functioning of the cardiac and respiratory systems is restored, a number of diagnostic procedures are performed.

How to prevent electrical injury?

Prevention of electric shocks is based on strict adherence to established safety and labor protection rules. The types of electrical injuries that occur as a result of prolonged exposure to an electric field can be prevented through the use of shielding generators, protective rubber suits, and also by periodically undergoing comprehensive medical examinations.

Electric shock in childhood is fraught with severe and irreversible consequences, and therefore it is important to limit the child’s access to electrical appliances, wires, and sockets as much as possible.