Terminology and Types of Electrical Burns Initial Assessment and Management High Voltage Electrical Injury: Diagnosis and Treatment Low Voltage Electrical Injury: Diagnosis and Treatment

1. Initial Assessment & Management

Stop the Burning Process Neutralize the heat source Remove smoldering clothing

Airway Assess patency of airway consider the presence of smoke inhalation injury and carbon monoxide toxicity if smoke is present

Breathing Assess adequacy of breathing efforts (is there labored breathing, wheezing?) Remember that the electrical current can impair the ability to breathe Initiate respiratory assistance, if needed

Circulation Electrical burn to muscle acts like a crush injury Assess adequacy of circulation Shock from heart damage could be seen within minutes) IV placement and fluid administration Cardiac monitoring is indicated with electrical injury CPR and defibrillation per diagnosis and protocol Remove potentially constricting object, like jewelry Monitor pulse in extremities with contact point burn or thermal injury; looking for muscle or skin swelling, impairment to local circulation (compartment syndrome) Diagnosis of High Voltage Injury *History of contact including voltage source and exposure time *Presence of contact point burns

Disability Brain and nerve deficits are a common problem Determine status of consciousness and treat accordingly  (AVPU) Are all four extremities moving?

Expose & Examine Presence of contact point burns (if present then patient must be transported to a hospital, preferably a burn center due to the risk of the “hidden” injury) Assess for presence of arc or flash burns Assess for other traumatic injuries

History Contact time and exposure Voltage of electrical injury Voltage History of other traumatic injury

2. Overview & Terminology

An electrical current will produce an array of injuries if the current passes through the body. Most of the damage is beneath the skin surface and therefore the actual injury can easily be underestimated. There are often several possible components to the injury.

• The first component is the injury caused by the electrical current itself. The current (the current of injury) generates intense heat often in excess of 2000°F along its path through the body, which can lead to severe muscle, nerve and blood vessel damage.

Typical injuries * damage from sun * skin burn from an “arc” or flash * clothes on fire * blunt trauma In addition the electricity itself damages tissues especially nerves. The major of the damage is beneath the skin leading to a “hidden” injury.

The second component is the injury from "arcing".  Ionization of air particles associated with a voltage drop is called arcing. The heat generated in the arc can be as high as 4,000°C and can vaporize metal. This process frequently causes a patient’s clothing to ignite and cause flame burns. A form of explosion dissipates excess energy from the arc.

The third component is the skin burn caused by a flash. A flash can result from the power source or from the ignition of clothing or surroundings. A flame burn can occur  without underlying tissue injury.

The fourth component is traumatic injury caused by the intense muscle spasm with the current or from a fall. There is also a variety of cardiac, lung muscle, nerve and internal organ injuries which can occur, some being immediately life threatening.

 

High Voltage Injury

High Voltage Injury defined as exposure to a voltage of 1000 volts or greater (damage beneath the surface should be suspected). - injury is caused by passage of current - arc or flash from electrical source can cause severe skin burns - explosive force and falls can cause blunt trauma - cardiac, neurological and other injuries occur. A high-tension source is usually required to produce the tissue destruction characteristically seen along the path of the current. High-voltage injuries characteristically occur in an outdoor environment near power sources and lines. Electrical current can arc (jump) 1 inch from a power source or line for every 10,000 volts being carried, so that a person does not actually have to touch the source to sustain injury.

Low Voltage Injury

Low Voltage is defined as less than 500 volts (local heat damage is usually evident e.g. at the edge of the mouth in kids biting electric cords) -  current not sufficient to cause tissue damage along its course except at contact site - cardiac problems are common e.g. ventricular fibrillation Low-voltage injuries occur characteristically in a home or residential environment. Electrocutions in bathtubs and by electric hair dryers are the most common causes of low-voltage deaths. Contact Points of Injury The term “entrance and exit” sites are commonly used to describe the damage at a contact point with the electricity. These terms are really a misnomer when describing a high voltage AC current injury as the current is actually passing back and forth between contact with electricity and grounding site on the body. Low-voltage injuries usually only have a small burn (or no damage) at the point of contact. Contact Point with Electrical Source Previously called the entrance site, the wound will be found anywhere on the body in contact with the source. A burn is present at the site due to the high temperature at the surface. The heat can evaporate the water on skin leading to a sunken or hollowed area. Contact Point usually at grounding site This wound previously call an exit site is where the current comes to the surface. A small hole or large defect can be present depending on the size of the current and tissue resistance. The wound may look small but remember the damage is from the inside out and is therefore the damage is very deep.

Pathway of Current

The pathway of current can be somewhat unpredictable, but, in general, current passes from a point of entry through the body to a grounded site, i.e. , a site of lower resistance to flow compared with air, which is a poor conductor. Extremely high voltage sources usually exit in multiple areas in an explosive fashion. Current passing from hand to hand or hand to thorax has a high risk of producing cardiac fibrillation compared to hand to foot passage. Passage through the head is likely to cause an initial respiratory arrest and subsequent severe neurologic impairment.

3. High Voltage Electrical Injury

Pathophysiology
The pathway of current can be somewhat unpredictable, but, in general, current passes from a point of entry through the body to a grounded site, i.e. , a site of lower resistance to flow compared with air, which is a poor conductor. Extremely high voltage sources usually exit in multiple areas in an explosive fashion. Current passing from hand to hand or hand to thorax has a high risk of producing cardiac fibrillation compared to hand to foot passage. Passage through the head is likely to cause an initial respiratory arrest and subsequent severe neurologic impairment.
Common Complications
Ventricular Fibrillation	Muscle necrosis
Other rhythm abnormalities	Fractures
Respiratory arrest	Hemolysis
Seizures/Coma	Renal Failure
Mental changes	Hemorrhage
Hypertension	Limb loss
Retinal detachment	Anemia
Cataract (delayed)	Paresis/paralysis and other neurotic (delayed)

 

Skin Injury (Contact points)
The determination that a current injury to underlying tissue may be present is the finding of contact point sites. Their presence is diagnostic of an electrical injury beneath the skin.                                                                                              The heat generated at the skin surface is dependent on the local resistance, which in the dry hand can be sufficient to generate heat in excess of 1000°C with high-voltage sources. This will lead to local mummification at the entrance. The skin appearance at the site of contact is often that of a well-defined charred wound that is depressed due to loss of tissue bulk. The wound may sometimes appear like a typical deep flame burn, except in this case the injury extends deep into the surface.   The arc burn is basically a thermal burn caused by the intense heat generated from the high intension current arcing from the wire. Tissue appearance at the contact point of the ground varies considerably. With moderate exposures, the appearance is often that of small skin ulcerations with a depressed center and heaped up edges. With passage of a large current, multiple exit sites are frequently seen along the route of the current. The appearance is often that which would be expected from explosion, since pieces of cutaneous tissue are often absent, having been blown out by the immense energy of the exiting current.
Contact point with High Voltage Source
	Typical site would be the hand. There is a burn to the hand from generated heat. The entrance site is the blackened area on the wrist where there appears to be a defect as the water, in the skin, and beneath, has vaporized.
Contact point with High Voltage Source
	Injury is from 10,000 volts. There is obvious mummification or total destruction of the hand and the wrist is fixed in flexion as the tendons and muscles of the forearm have been destroyed. The loss of tissue water shortens the now dead tissue. The wound at the elbow crease resulted from the heat of the current as it traveled up the arm.
Contact point at Victim Grounding site
	The site where the passing current reaches the surface can often look like holes and appear innocuous. However, these wounds are deep as the current is coming from the inside out. A wound such as this, commonly seen on the foot, clearly indicates passage of a high voltage current through the body.
Contact point with surface
	A more dramatic contact point “blowout” type wound is shown where the fourth and fifth toes are destroyed.

 

Body Burns
Burns from the heat of an electrical arc, flash or clothes catching fire, are common with high voltage injuries.
	Intensive heat is generated when the high voltage current jumps to the victim from the source. This heat will cause deep surface burn. Clothes often catch fire as well.

 

Muscle Damage
Electrical burns more closely resemble a crush injury than they do a thermal burn. The damage below the skin where the current passes is usually far greater than the appearance of the overlying skin would indicate. The immediate damage to muscle is caused by the heat, which is usually patchy in distribution along the course of the current, often most severe near the bones. Within minute of injury the dead muscle releases its red pigment, myoglobin, into the blood stream. The muscle rapidly swells compressing local nerves and blood vessels. An incision through the overlying layers will be necessary to release the pressure (called a fasciotomy).
Electrical Burn with Dead Muscle
	The pale looking dead muscle is beneath normal skin, near the mummified foot (contact point). An invasion has been made to avoid the pressure of swollen muscle from damaging nerves and remaining living muscle.
Muscle Pigment in Urine
	The dark nearly black urine on the left is caused by the muscle damage and pigment release. The urine gradually gets clearer over 24 to 48 hours with fluid resuscitation, however, kidney failure can result.

5. Heart & Blood Vessel Injury

Immediate cardiac arrest is the most common cause of death after electrical injury. The process is due to both the direct alteration of rhythm by the current, leading to fibrillation or to the depression of respiration and subsequent hypoxia. Hand to hand passage of a high voltage current has a reported immediate mortality of 60%. The initial heart problems are often reversible with CPR. High blood pressure is also quite common immediately after injury.

6. Lung Injury

Impairment of the brain centers stimulation of breathing and severe central nervous system damage will lead to lack of breathing, which is frequently the cause of immediate death. Decreased muscle activity in the chest wall caused by a chest burn, muscle damage, or second-degree blunt traumatic injuries can markedly impair breathing.

7. Neurologic Injury

Acute central nervous system damage with coma, seizures, motor and, to a lesser extent, sensory deficits are well described. Many of these abnormalities are permanent.

8. Orthopedic Injury

Orthopedic injuries occur as a result of three processes: Muscle spasm-induced fractures and dislocations Heat-induced local bone destruction Devascularizaton of bone The most common orthopedic injury occurs as a result of severe immediate muscle spasm, which is capable of producing long bone fractures and dislocation at major joints. Heat necrosis of local periosteum with subsequent production of non-viable bone and sequestrum formation is the next most common process. Devascularization of bone due to the same vascular injury affecting other tissues is less common.
Humerus fracture from initial muscle spasm
	Humerus fracture caused when the muscle went into intense spasm with contact with the current.

9. Eye & Ear Injuries

Conjunctival and corneal burns as well as ruptured ear drums are well described early changes.

4. Low voltage electrical injury (up to 500 volts)

Pathophysiology Tissue Necrosis or severe burns are not not present Cardiac Problems - The most severe injury is electrocution as a household current applied to wet skin is sufficient to cause ventricular fibrillation and cardiac arrest (only 60 milliamps is required). Other rhythm disturbances can also occur. Muscle Spasm - Tetany and spasm can also develop with contact with low voltage. The “can’t let go” current is only 30 milliamps. The spasm in the flexor muscles in the hand and forearm prevents the victim  from letting go. Suffocation can also occur if the chest muscles go into spasm as the victim can’t breathe. This problem is most commonly seen with immersion in water like a bath tub. Oral Burn - Low-voltage electricity is the leading cause of electrical injury in children, especially 1 to 2 year olds. Sucking an extension cord is responsible for more than half of the injuries, and biting on an electric cord accounts for about 30%, The most common mechanism is the production of an electrical arc by the bared wires conducted by the child’s saliva. Intense local heat is generated, producing severe local destruction of mouth tissues. The local mouth burn is characteristically grayish-white in color and indented at the center due to tissue necrosis. Severe swelling then develops a venous thrombosis impedes blood return. The oral burn may involve lip, tongue or oral mucosa and underlying bone. The most frequent site is the lip, in particular the commissure area between upper and lower lip. The swelling of the lips may be intense, impairing control of saliva. Swelling subsides over the next 5 to 10 days and local necrotic tissue begins to slough. Bleeding from labial artery at the edge of the mouth is a common occurrence (20%) during the period of slough (7 to 21 days) and should be anticipated. Pressure control of bleeding will be necessary.
Oral Burn
	Typical appearance of an electrical cord burn.