A Shocking Call

Medic 4 responds to a golf course on the report of a person struck by lightning. Upon arrival, on-scene first responders are breathing for the victim. After interviewing bystanders, the EMS crew learns that the first responders witnessed the patient collapse and applied an AED, at which time a shock was indicated. After they delivered a single shock, the patient regained a pulse and had weak and ineffective respirations.

The EMS crew supports the patient's ABCs as he is moved to the ambulance. The patient is a male in his 40s, who is unresponsive with occasional respirations. His heart rate is 40, sinus bradycardia with ST elevation. Blood pressure is 72/40. His skin is cool, pale and dry. Pupils appear to be dilated with a sluggish response to light. Aside from wounds to the patient's left hand and right foot, there are no other obvious signs of physical trauma. From bystander reports, his medical history is unremarkable and there were no ingestions of drugs or alcohol. Emergent transport is initiated. During transport, the patient remains unconscious with a heart rate in the 50s and blood pressure of 90/52. He continues to require manually supported ventilation.

INTRODUCTION

Electrical burns account for 4%-6.5% of admissions to burn units in the United States and almost 1,000 fatalities every year, most of them occupationally related.^1-3 Participants in sports and recreational activities are common victims, with mountain activities (climbing, hiking, etc.), golf and water activities accounting for the largest number of fatalities and injuries.⁴

EMS providers respond to a variety of scenarios. While many of these scenarios fall under the category of medical or trauma, electrical injuries and lightning strikes can present as a combination of both. Because of this, providers must not only address the traumatic outcomes from the incident, such as burns or blunt force trauma, they must also consider any potential medical issues, such as cardiac arrhythmias.

ELECTRICAL INJURIES

Electrical injuries involve the exchange of energy influenced by two laws: Ohm's and Joule's (see Table 1).⁵ The body's resistance to electrical current varies, depending on factors such as body moisture and temperature, as well as the path taken by the electrical current (see Table 2). In essence, the greater the tissue's resistance to the flow of current, the more likely the electrical energy will be transformed into thermal energy. Nerves, muscles and blood vessels, which have high electrolyte and water content, have low resistance and are good conductors. In contrast, bones, tendon and fat have a high resistance and tend to become heated when exposed to electrical current rather than transmitting the current.⁶

Electrical current can be low voltage (&llt;1000 volts) or high (>1000 volts) and direct (DC) or alternating (AC) (Table 3).^5-7 Electrical injuries account for approximately 6% of admissions to burn units; approximately one-third of electrical trauma cases are job-related. Electrical injury remains the sixth-leading cause of occupational fatalities. Fewer than one-quarter of electrical injuries involve children. Electricians, construction workers, golfers and toddlers are some of the more common victims.^7-9

Exposure to electricity can result in a variety of injuries, including damage to muscles, tissue necrosis and vascular damage. For example, burns can result if an individual becomes part of an electrical "arc." An arc is created when an object that is not in contact with an electrical source becomes involved. Consider the person who is standing next to a car that is in contact with a downed power line. Even though the person is not in physical contact with the car or power line, he may be injured if an arc is formed between him and the car.

A variety of injuries are possible from an arc. Burns due to arcing are influenced by factors including the heat of the arc, electrothermal heating due to the current's flow, and by the flames that result from ignition of clothing. In addition to the arc, the electrical current may splash across the entire body, resulting in burns.²

The current's pathway also influences the type and severity of an injury. For example, electrical current that passes through the head or thorax is more likely to be fatal than current that is isolated to an extremity. Transthoracic currents can result in dysrhythmia, direct cardiac damage or respiratory arrest. Transcranial currents can cause direct brain injury, seizures, paralysis or respiratory arrest.⁵

SYMPTOMS OF ELECTRICAL INJURY

Depending on the mechanism of the electrical injury, entry and exit wounds, sometimes referred to as contact and ground points, may be present. When AC is involved, the hand is the most common site of contact. Holding a tool that contacts an electrical source or grasping a wire are methods for electrical injuries to occur. Because of muscular tetany, when the current involves the arm, the hand of the arm that is grasping the current source may pull the body closer to the source, as opposed to releasing that source.^10,11

An entrance wound may appear to be indented, with a depressed area of gray or yellow discoloration and full-thickness tissue destruction. The exit wound may appear to be flared outward, with dark discoloration surrounding the wound. The majority of wounds associated with an electrical injury tend to be located in the upper or lower extremities.^10,11

Because of the numerous factors involved with an electrical injury, providers should pay attention to entrance or exit wounds. While the wounds may be graphic, they may only hint at the actual severity of possible injuries. Providers must consider the potential for internal and multi-systems trauma in victims of electrical injury.¹²

Symptoms of electrical injury can range from tingling sensations to complete paralysis. Any organ or system may be impacted, and factors like the source of electricity, path of the current and the patient's underlying health influence the severity of the injury. For example, burns may occur as the result of tissue heating. Injury to the nervous system may result in respiratory distress or cardiac arrest. Additional trauma may occur if the victim falls or is thrown as a result of the electrocution. Injury severity will vary and is influenced by the forces that were involved.¹²

In the prehospital setting it may not be possible to determine the exact extent of internal injury. Cardiac dysrhythmias are possible, with ventricular fibrillation being the most common. It occurs in more than 50% of the patients in whom the current pathway transverses the body as it goes from one hand to the other. In children under age 4, a common injury is a mouth burn when the child chews an electrical cord.¹² These injuries can be extremely dangerous and warrant close and extended observation due to the potential for delayed bleeding, which can be extensive.

LIGHTNING STRIKES

Lightning is an electrical discharge that occurs between groups of positive and negative electric charges in the atmosphere. Lightning is most often associated with thunderstorms, including cumulonimbus (thunder) or nimbostratus clouds. Winter lightning, referred to as thunder blizzard (thunder snow), is rare and more dangerous because it tends to be more powerful than summer lightning. Lightning is dangerous for a variety of reasons, including electrical effects, heat production and concussive force.^2,9 More information on lightning can be found at www.uic.edu/labs/lightninginjury/psycho.html.

Lightning injuries tend to occur in rural or exposed/open environments, as opposed to urban settings. In urban settings, many buildings have metal frames and/or lightning-protection devices. Lightning tends to be more common in the afternoon because the ground is heated throughout the day. Lightning can have either a negative or positive charge, with negative being more common. The temperature of lightning has been estimated to be about 8,000°C (14,432°F) and as high as 50,000°C (90,032°F). The temperature falls in less than a second to 2,000°C-3,000°C (3,632F°-5,432°F).^2,9 Despite the extremes in temperature, providers do not need to delay contacting the patient for fear of being injured.

Lightning has many forms,^2,9 as seen in Table 4, and different patterns can occur. For example, splash strikes occur when lightning hits a tree or building and then "splashes" onto a victim. In these cases, the current jumps to a person whose body has less resistance than the tree or object that was initially struck. Splashes can occur from person to person in a crowd. Splash strikes can also involve lightning hitting a fence or other long conductive object, even when the strike location is some distance away, as the electrical current travels along the conductive object.^2,9

Another possible source of exposure to lightning is a side flash, which tends to occur while an individual is inside a structure and is due to conductive sources such as metal objects (e.g., washing machine), plumbing or landline telephones transmitting the current. The landline telephone system may not be grounded to the house's electrical system and the phone may act as a point for lightning to either enter or exit the house.^2,9

Step voltage, also referred to as stride voltage or ground current, occurs when lightning strikes the ground or a nearby object. After striking, the current spreads in a manner similar to waves in a pond. This occurs because there is a difference between the resistance of the earth's surface and the human body that creates an opportunity for the current to pass through the lower resistance of the victim rather than stay in the ground. Swimmers may become involved as the current passes through them while they are in the water.^2,9

Lightning strike injuries can be described as minor, moderate or severe (Table 5). In minor cases, the patient is often awake and alert, although he may experience confusion or amnesia, and his skin may be sensitive and painful to the touch. Physical findings may be temporary, and complete recovery can occur.^2,10

Patients with moderate injuries may experience disorientation and be combative or unconscious. If conscious, they may report extremity paralysis. The skin may be mottled and distal pulses diminished. Hypotension can occur secondary to physiologic changes. When hypotension is present, providers should attempt to determine the cause (e.g., blood loss, spinal shock or fracture), as this will guide treatment. Respiratory arrest from hypoxia or other factors, such as central nervous system impairment, can lead to cardiopulmonary arrest. Burns may not be obvious in the field and their development can be delayed. Physical symptoms may resolve over time; however, long-term sequelae, which can include sleep disorders, generalized weakness and nervous system dysfunction, can develop.^2,10

Serious injury or death occurs in about 30% of victims, with injuries ranging from blunt trauma to cardiopulmonary arrest. Ventricular asystole and fibrillation are two common dysrhythmias. Because of the heart's automaticity, cardiac activity may return spontaneously, with the initial heart rate tending to be bradycardic. Cardiac function may subsequently deteriorate in part from the apnea that results from paralysis of the respiratory center in the medulla. Hypoxia can lead to secondary cardiac arrest.^2,10

Following a lightning strike, it is important to evaluate cardiac function. EKG changes may occur from the electric injury or from burns to the myocardium. EKG changes are often similar to those seen in the setting of an acute MI, including ST segment elevation, T-wave inversion and prolonged QT intervals. Early and continuous cardiac monitoring is indicated.^2,10

Pulmonary edema may develop as a result of myocardial insult from the lightning strike. Hemoptysis and pulmonary hemorrhage may result from blunt injury or other pulmonary trauma. Providers are encouraged to administer oxygen to all victims of electrical injuries and lightning strikes.^2,10

Vasomotor spasms are often the result of sympathetic stimulation. Because vasoconstriction can be intense, it can result in the loss of distal pulses. This may result in extremities that are mottled and cool. Vasoconstriction can also lead to brief paralysis of the involved extremity. This is thought to be due to temporary ischemia of the peripheral nerves. The absence of distal pulses in extremities that are mottled and cool should be considered a significant finding.^2,10

Hypo- and hypertension may be present. Hypotension due to lightning tends to be self-resolving; however, persistent hypotension should be carefully investigated for specific causes such as hemorrhage. Hypertension secondary to lightning strike also tends to be transient. In the prehospital setting, treatment beyond intravenous fluid replacement is rarely required.^2,10

Injuries to nervous systems are possible, including amnesia, confusion, loss of consciousness, weakness, intracranial injuries (e.g., epidural/subdural hematoma) and aphasia. Paralysis of the respiratory center may occur. Headaches, nausea, vomiting, dizziness and tinnitus have been described. Central nervous system injury can be so acute that a rapid onset of cerebral edema occurs, with subsequent brain stem herniation. Complete extremity paralysis is referred to as keraunoparalysis and is associated with sensory loss and cyanosis. More than half of the victims of lightning strike experience paralysis. Nearly 70% of cases will involve the upper extremities, while the remaining 30% will involve the legs.^2,10

Lightning victims may experience anterograde amnesia and confusion that can last for several days. Retrograde amnesia is less common. The patient may appear to be oriented and remember his actions before the strike, but may not be able to recall new experiences for several days.^2,10

A burst-like injury can also occur. In this situation, the patient's clothes are torn outward and an open wound is present. This is commonly seen in the foot, where the shoes and socks are torn apart.^2,10

The ears are the most sensitive organs to lightning injury. Nearly half of lightning victims will experience rupture of one or both tympanic membranes. This may be from the shock wave effect, basilar skull fracture or direct burn damage because of current flow. Temporary deafness has been reported.^2,10

Lightning strike survivors may experience sequelae after the injury, including anxiety, hyperirritability, memory deficits, aphasia, sleep disturbance, peripheral neuropathy and chronic pain syndromes. Neuropsychologic symptoms include severe short-term memory difficulty, difficulty processing new information and depression (Tables 6 and 7).^2,10

INDUSTRIAL HIGH VOLTAGE VS. LIGHTNING EXPOSURES

There are differences between lightning and high-voltage electrical accidents (see Tables 8 and 9 for an overview). One of the biggest differences tends to be that lightning contact is almost instantaneous, whereas high-voltage tends to be prolonged due to the victim "freezing" to the circuit. Deep injury and burns are not as common with lightning strikes.⁵

BURNS IN ELECTRICAL INJURIES AND LIGHTNING

Either an electrical injury or a lightning strike can involve burns, although they may not be obvious initially and may not be present on external examination. When present, burns should be assessed for severity and body surface involvement.^10,11,13 Additional information on burns can be found at www.burnsurvivor.com/burn_types.html.¹³ Burn severity will vary in each case and is influenced by numerous factors such as voltage, amperage, resistance, pathway and duration of the exposure.

Burns associated with lightning may be divided into five categories: linear; punctate full-thickness; feathering or flowers; thermal from ignited clothing or heated metal; and any combination of these (Table 10).^10,11 Survival rates vary. Patients with cranial burns are four times more likely to die than those who do not have them. Those with cranial burns are also two and a half times more likely to have a cardiopulmonary arrest than those without. Persons with leg burns are five times more likely to die than those who have no leg burns.^10,11

Obtaining a thorough history and sequence of events may prove very valuable. Questions to ask include: Where was the patient located when the injury occurred? What is the potential source of the electrical injury? When did the initial event occur? How long has the patient been in his current condition? Has there been any improvement in the patient's condition? What treatment has been provided? What is the patient's baseline health status? Does the patient take any prescription medications, and, if so, is he compliant?^14–16

Bystander reports are helpful, as the victim may be confused and unable to recall the events. The history should include a description of the event, as well as the victim's behavior before and following the event.^14–16

SCENE SAFETY

Providers should avoid touching any patient who is in contact with a potentially live wire or electrical source. Using nonconductive objects like a wooden pole to move live wires is not recommended, as they may still conduct alternating current.^14-16 If there is a live contact between the source (e.g., wire) and the object (e.g., car), the surrounding ground may be electrified as well. A safe distance is about 30 feet; however, this is variable depending on voltage, current and the environment. Only individuals with specialty training to use certain equipment (e.g., electrical gloves) should use them. Any defect in equipment or technique could result in injury or death.

In cases where the patient remains in contact with the source of electricity, providers should either wait to provide care until appropriately trained personnel are on scene, or wait until the power source has clearly been disconnected. In many cases, electrical lines are connected to a backup generator. Even if the main power source is turned off, the line may still be charged from a backup system. If the status of power is unclear, using individuals specifically trained in removal of such sources is recommended. Provider safety is of paramount importance and is at particular risk when caring for patients of lightning or electrical injuries.^14-16

In lightning strike scenarios, because there are no live wires, it is usually safe to contact the patient. In most cases, when EMS arrives on scene, the lightning strike event will be over, and establishing physical patient contact will not place the crew at risk. Patient assessment and treatment can be done immediately.^14-16

PATIENT MANAGEMENT

The primary focus is to assess and secure the airway, breathing and circulation. Because of the potential for ventricular fibrillation and other cardiac arrhythmias, early EKG monitoring is recommended. Support of the patient's ABCs can include manual airway support, artificial ventilations, CPR and defibrillation. Correction of hypoxia via a secured airway and effective ventilations is essential when the patient is not adequately ventilating on his own.^14-16

A brief neurological assessment can be conducted in the field using tools like the AVPU method or Glasgow Coma Scale.^14-16 A complete set of vital signs, including heart rate, EKG monitoring, blood pressure, skin temperature and respiratory rate, should be obtained as early as possible. Breath sounds and respiratory effort should be rapidly assessed and monitored.

Electrical energy may cause muscle tissue damage. This can result in edema and may lead to reduced blood supply. The patient may report numbness, tingling or pain. A neurological and circulatory assessment should be conducted and distal pulses, neurological sensation and perfusion assessed.^14-16

Assess the patient's pupils, noting size, reactivity and the ability to track movement. The presence of abnormal findings, such as nonreactive and dilated pupils, should be noted, but may not be diagnostic.^14-16

Following an electrical injury or lightning strike, the patient may appear to be confused or respond inappropriately. This can be the result of a variety of mechanisms, including hypoxia, cerebral insult or tympanic membrane rupture. Due to possible tympanic membrane involvement, patients might not be able to hear well. This can inhibit their ability to respond appropriately to verbal communications, hence making them appear confused.^14-16

HYPOXIA

In an effort to avoid hypoxia, support the patient's airway and respiratory drive as needed and administer supplemental oxygen. Remember that because hypoxia can lead to secondary cardiac arrest, supplemental oxygen administration and airway management take priority.^14-16

INJURIES

A variety of injuries may be encountered, depending on the exact mechanism involved. Blunt injuries can occur in the setting of electrical injuries from falls, muscle tetany or blasts. Penetrating injuries may be present at the entrance and exit locations. Manage life-threatening injuries as they are identified.^14-16

TISSUE DAMAGE & FLUID REPLACEMENT

In the field, it is not possible to determine the extent of tissue damage. Because of the unpredictable nature of electrical injuries, estimating fluid loss is extremely challenging. The presence of burns should trigger providers to suspect fluid loss.^14-16

Fluid replacement will be guided by a variety of factors, including the patient's overall condition and local protocols. In the prehospital setting, following an electrical injury or lightning strike, hemorrhage, hypotension and/or burns should be managed in part via fluid boluses. One goal of resuscitation is to avoid renal failure and development of myoglobinuria, or rhabdomyolysis. Rhabdomyolysis is the breakdown of muscle fibers, resulting in release of muscle fiber contents into the circulation. This can be toxic to the kidneys and may result in kidney damage. When muscle is damaged, it can release myoglobin in the urine and lead to tubular necrosis and renal failure with long-term consequences if not treated appropriately.^14-16

Fluids like normal saline or Ringer's lactate should be infused in accordance with local protocols. Closely monitor fluid administration to avoid pulmonary or cerebral edema.^14-17 Traditional treatment guidelines for burn victims, such as the Parkland formula, may be appropriate to guide fluid administration in lightning and electrical injuries, as obvious injuries to the skin often do not accurately reflect the true extent of the damage.¹⁷ (For an example, see: https://kallus.com/er/calcula tions/parkland.htm.)

BURN TREATMENT

Note baseline skin findings. Burns may not be present in the field and development may be delayed. Circumferential burns, which are burns that encircle a body part, may require surgical intervention.^14-16 Burn treatment may include application of dry dressings and removal of loose clothing. Use of ointments or other burn solutions in the prehospital setting should be based on local protocols. Unless skin is flaking or sloughing off the patient, it should be left in place.^14-16

ANALGESIA

Pain relief through analgesia like fentanyl and morphine sulfate may be considered in these cases. Unless contraindicated (e.g., hemodynamic instability), pain relief could be incorporated into the overall treatment plan. The combination of these medications can provide rapid relief. Fentanyl has a very rapid onset and is often the most potent narcotic analgesic carried in prehospital settings. Morphine sulfate takes longer to reach maximal effect and is not as potent as fentanyl, but peaks just as the fentanyl is starting to wear off. Patients with pain secondary to lightning strike or electrocution may have pain for a longer period of time than single doses of fentanyl can provide relief for. As a result, consider adding a longer-acting medication like morphine.

VITAL SIGNS

It is essential to continually assess and monitor the patient's vital signs. Note any changes and investigate potential causes. Cardiac monitoring should be ongoing throughout prehospital care. While a variety of EKG changes may occur, not all will require immediate intervention. Lethal cardiac rhythms, such as ventricular fibrillation or asystole, certainly require immediate intervention.^14-16

Monitor the patient's body temperature throughout transport and remove wet clothing. Keep the patient dry and covered.^14-16

DESTINATION

The destination of the patient suspected of being involved in an electrical injury will vary, depending on a number of factors. Burn centers, when available, are good choices for victims of significant electrical injury. When any significant trauma is involved, a trauma center should be selected, if available. The ideal situation would be a burn center that also accepts trauma patients; if this is not the case, the need for trauma resources takes priority over the need for a burn center.^14-16

CONCLUSION

Because electrical injuries and lightning strikes are encountered to one degree or another in most EMS systems, providers are encouraged to become familiar with the mechanisms of injury associated with these events. With this knowledge, EMS crews will be better prepared to assess and manage these cases, potentially improving patient outcomes.

References

1. Lee R. Injury by electrical forces: Pathophysiology and emergency management. Current Problems in Surgery 34, p. 684. St. Louis: Mosby, 2007.

2. Cooper M, Andrews C, Holle R, López R. Lightning Injuries. Wilderness Medicine, 4th Ed. St. Louis: Mosby, 2001.

3. Price TG, Cooper MA. Electrical and lightning injuries. In Marx JA (ed): Rosen's Emergency Medicine: Concepts and Clinical Practice, 6th ed. Philadelphia: Mosby, 2006.

4. Cherington M. Lightning injuries in sports. Sports Medicine 31(4), 2001.

5. Daley B, Mallat A. Electrical Injuries. emedicine.com. www.emedicine.com/med/topic2810.htm.

6. AllAboutCircuits.com. Physiological effects of electricity. www.allaboutcircuits.com/vol_1/chpt_3/2.html.

7. Public Health Service. Worker Deaths by Electrocution. A Summary of NIOSH Surveillance and Investigative Findings. Centers for Disease Control and Prevention. National Institute for Occupational Safety and Health. www.cdc.gov/niosh/pdfs/98–131.pdf.

8. Kisner S, Casini V. Epidemiology of Electrocution Fatalities. Center for Disease Control and Prevention. National Institute for Occupational Safety and Health. www.cdc.gov/niosh/elecepid.html.

9. Cawley J, Homce G. Trends in Electrical Injury, 1992-2002. NIOSH. https://0-www.cdc.gov.mill1.sjlibrary.org/niosh/mining/pubs/pubreference/outputid2103.htm.

10. Edlich R, Drake D. Burns, Lightning Injuries. www.emedicine.com. www.emedicine.com/plastic/topic517.htm.

11. Edlich R, Drake D. Burns, Electrical. www.emedicine.com. www.emedicine.com/plastic/topic491.htm.

12. Wikipedia. Electric Shock. https://en.wikipedia.org/wiki/Electric_shock#Psychological.

13. Burn Survivor Resource Center. Medical Care Guide, Types of Burns. www.burnsurvivor.com/burn_types.html.

14. Hubble M, Hubble J. Principles of Advanced Trauma Care. Albany: Delmar Thompson Learning, 2002.

15. Bledsoe B, Porter R, Shade B. Paramedic Emergency Care. Upper Saddle River, NJ: Brady Prentice Hall, 1997.

16. Campbell J. Basic Trauma Life Support for Paramedics and Advanced EMS Providers. Englewood Cliffs, NJ: Brady, 1995.

17. Stony Brook University Medical Center. Calculators and protocols. Parkland Formula for Burn Fluid Management. https://kallus.com/er/calculations/parkland.htm.

Paul Murphy, MA, MSHA, is a paramedic with administrative and clinical experience in healthcare organizations.

Chris Colwell, MD, is medical director for Denver Paramedics and the Denver Fire Department, as well as an attending physician in the emergency department at the Denver (CO) Health Medical Center.

Gilbert Pineda, MD, FACEP, is medical director for the Aurora Fire Department and Rural/Metro Ambulance (Aurora, CO) and an attending physician in the emergency department at The Medical Center of Aurora and Denver Health Medical Center.

Tamara Bryan, BS, EMT-P, has more than a decade of healthcare experience, including clinical and project management roles.