Types of electric injury

Electric current may cause burns, heating vascular and nervous system, heart, brain (thermal effect); electrolyze of liquid, violation of physical and chemical blood structure (chemical effect); tear of tissues, fracture (mechanical effect); changing biological processes and, irritating tissues (biological effect). All mentioned effects result in electric injury and shock.

Electric traumatism is event compiled from totality of electric injuries occurring and repeating in occupational, home, recreational or volunteer situations. Electric injuries are caused by temporary or permanent situations, which are followed by accident during exploring of power facilities.

Electrical injury is consequence of electric current or arc action. It may be of two types: those, which are caused by electric current passing through the body, and those which occur without electric current passing through the body.

There are local and total electric injuries.

Local electric injury results in local damages of the organism. Frequently they cause damage of skin, soft tissues, and bones. Local electric injuries are typically reversible and recovery is full or partial. However heavy electric burns can be fatal.

Electric injuries statistically have the following risk rating, %:

- electric burn – 40;

- electric trace –7;

- electric metallisation – 3;

- mechanical damage – 0.5;

- electric ophthalmia – 1.5;

- electric injury of composite type – 23;

- total – 75.

Electric burn can be of two types: current burn, which occurs when electric current passing through the human body, and arc burn caused by high temperature of electric arc, that reaches over 3500 °C.

Electric trace is the clearly identified spot of gray or light-yellow color of 1 - 5 mm in diameter, that appears on the skin effected by electric current.

Electric metallisation is penetration into skin of metal particles when it’s sputtering and vaporizing under high voltage. It may occur on knife-switch disconnecting and short circuit. This injury is observed in about 10% of accidents.

Simultaneously with metallisation the arc burn occurs that is always even more hazardous than metallisation.

Mechanical damage of body appears as result of cramp during electric current passing through body. The consequences of that can be tears of ligament, skin, blood vessel and nervous tissue, fractures of bone. They happen during longtime exposure to voltage up to 1000V.

Electric ophthalmia is irritation of eyes’ mucous membrane that occurs being exposed to intensive ultraviolet luminous flux. That exposure is produced by electric arc (short circuit). Electric ophthalmia develops 4 - 8 hrs after exposure. It causes irritating skin, mucous membrane, tears, eye’s pus, eyelids’ cramps, partial loss of sight. It feels headache and acute eye pain, which is growing on light.

Electrical shock is exciting of living tissues by electric current followed by cramps. It’s most dangerous effecting heart or lungs and may be fatal. Electrical shocks may effect differently. The least shock slightly feels as muscle contraction close to the area where current goes in or out. Shock of greater intensity can violate or even stop lungs and heart functioning, what means be fatal. Electrical shocks can be classified to make 5 classes according to consequences they cause:

I - slight muscle contraction;

II - cramp muscle contraction followed by great pain that can hardly be sustained without loss of consciousness;

III - cramp muscle contraction with loss of consciousness but respiration and pulse is still present;

IV - loss of consciousness and violation of heart functioning or/and respiration;

V - clinical death, what is absence of pulse and respiration.

Clinical death is a transient period from life to death. Clinical death indication is stop of heart functioning, consequently it’s observed as no pulse, no breathing, pallor and blue skin color, wide eyes’ pupils not reacting to light as consequence of oxygen starvation of brain. Brain cells die during clinical death. It lasts 6 - 8 min, then it comes biological death.