PREHOSPITAL EMERGENCY MANAGEMENT OF ELECTRICAL INJURIES

1. PREHOSPITAL EMERGENCY MANAGEMENT OF ELECTRICAL INJURIES

2. DEFINITION An electrical injury is damage to the skin or internal organs when a person comes into direct contact with an electrical current.

4. Factors Determining Electrical Injury Type of circuit Resistance of tissues Amperage Voltage Current pathway Duration Environmental factors

5. Body Tissue Resistance Least Nerves Blood Mucous membranes Muscle Intermediate Dry skin Tendon Fat Most Bone

6. Symptoms Symptoms depend on many things, including the type and strength of voltage, how long you were in contact with the electricity, how it moved through your body, and your overall health. • Changes in alertness (consciousness) • Broken bones • Heart attack • Headache • Problems with swallowing, vision, or hearing • Irregular heartbeat • Muscle spasms and pain • Numbness or tingling • Breathing problems or lung failure • Seizures • Skin burns

7. LOW VOLTAGE ELECTRICAL INJURY (UP TO 500 VOLTS) Pathophysiology Tissue Necrosis or severe burns Cardiac Problems Muscle Spasm Oral Burn

8. Low Voltage Electrical Injury

10. 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. ) 

11. HIGH VOLTAGE ELECTRICAL INJURY 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) 

12. HIGH VOLTAGE INJURIES

13. 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.

14. MECHANISM OF ELECTRICAL INJURY • DIRECT CONTACT • ARC • FLASH • THERMAL • BLUNT TRAUMA

15. MECHANISM OF ELECTRICAL INJURY • Direct contact: Current passing directly through the body will heat the tissue causing electrothermal burns, both to the surface of the skin as well as deeper tissues, depending on their resistance. It will typically cause damage at the source contact point and the ground contact point. Contact burns are shown in the image below. • Electrical arcs: Current sparks are formed between objects of different electric potential that are not in direct contact with each other, most often a highly charged source and a ground. The temperature of an electrical arc can reach 2500-5000o C, resulting in deep thermal burns where it contacts the skin. These are high-voltage injuries that may cause both thermal and flame burns in addition to injury from direct current along the arc pathway. • Flame: Ignition of clothing causes direct burns from flames. Both electrothermal and arcing currents can ignite clothing. • Flash: When heat from a nearby electrical arc causes thermal burns but current does not actually enter the body, the result is a flash burn. Flash burns may cover a large surface area of the body but are usually only partial thickness.

16. Direct contact

17. FLASH BURNS

18. Electrical arcs are formed between areas of different electrical potential that are not in direct contact with one another. The charge needed to create an electrical arc is usually very high, and associated temperatures can reach 2500-5000°C.

19. FALLS

20. High Voltage Is More Likely to Kill Than Low Voltage-A MYTH A momentary dose of high voltage electricity is not necessarily fatal. Low voltage is just as likely to kill as high voltage.

21. TYPE OF CIRCUIT • High-voltage direct current (DC) tends to cause a single muscle spasm, often throwing the victim from the source, resulting in a shorter duration of exposure but increasing the likelihood of traumatic blunt injury. • Alternating current (AC) is said to be about three times more dangerous than direct current of the same voltage, because continuous muscle contraction, or tetany, occurs when the muscle fibers are stimulated at between 40 and 110 times per second. The frequency of electrical transmission used in the United States is 60 Hz. Tetany occurs even at very low amperages.

22. FACTORS DETERMINING SEVERITY JOULE’S LAW: Power (watts) = Energy (Joules) time = V x i = i2 x R

23. Mechanisms of Injury Direct effect of electrical current Thermal burns Mechanical Trauma Post-trauma sequelae 20 December 2019 23

24. BURNS This definition describes a burn injury as damage to the skin and underlying tissues such as the subcutaneous tissues, muscle and even bone in the case of electrical injury. Burn injuries can be caused by heat (thermal injury), chemicals or by contact with electricity.

25. Primary Complications and Causes of Death in Electrical Injuries Cardiopulmonary arrest Overwhelming injuries Cardiac arrhythmias Hypoxia and electrolytes Intracranial injuries Myoglobinuric renal failure Abdominal injuries Sepsis Tetanus Iatrogenic Suicide

26. SCENE SAFETY Create a safe environment for bystanders and rescuers. The victim may still be part of a live circuit. Therefore, turn off the power source before approaching the victim or the surrounding area. Particularly for high-voltage injuries, the safest approach is to involve authorized personnel, such as the local power company, in disconnecting the power source.

27. CHECK RESPONSIVENESS AND CALL FOR HELP-1099,102,100

28. PRIMARY SURVEY • Immediately life threatening conditions are identified and emergency management begun. • A. Airway maintenance with cervical spine control • B. Breathing and ventilation • C. Circulation with haemorrhage control • D. Disability - neurological status • E. Exposure + environmental control • F. Fluid resuscitation proportional to burn size

29. A. Airway Maintenance With Cervical Spine Control • Clear the airway of foreign material and open the airway with chin lift/jaw thrust. Keep movement of the cervical spine to a minimum and never hyperflex or hyperextend the head and neck. • Injuries above the clavicle, such as facial injuries or unconsciousness, are often associated with cervical fractures.

30. B. Breathing and Ventilation • Expose the chest and ensure that chest expansion is adequate and equal. • Ventilate –Mouth to mouth or Mouth to Mask. • Always provide supplemental oxygen. • Carbon monoxide poisoning may give a cherry pink, non breathing patient.

31. C.Circulation With Hemorrhage Control • Check the pulse - is it strong or weak? • Capillary blanch test - normal return is two seconds. Longer indicates hypovolaemia. • Stop bleeding with direct pressure. • Mental obtundation occurs with loss of 50% of blood volume. • Pallor occurs with 30% loss of blood volume.

32. D.Disability: Neurological Status • Establish level of consciousness: • A - Alert • V - Response to Vocal stimuli • P - Responds to Painful stimuli • U - Unresponsive • Examine the pupillary response to light. They should be brisk and equal. • Be aware that hypoxaemia and shock can cause restlessness and decreased level of consciousness.

33. E. Exposure With Environmental Control • Remove all clothing and jewellery • Area burned is estimated by using the Rule of Nines or a burn body chart. • Keep the patient warm

34. Depth of burn

35. Dressing • Cleaning the wound- saline, soap and water, or chlorhexidine 0.1% solution • Dressing – occlusive dressings with topical cream- SSD, Soframycin • Elevation-Elevation of the burned part is useful during initial treatment as it tends to limit swelling.

36. Special areas Respiratory burns (thermal burns of the upper airway) are often associated with rapidly accumulating swelling and early intubation is necessary. Burns of the perineum require early urinary catheterisation in order to prevent contamination. Head and neck burns should have elevation of the head to limit upper airway swelling.

37. History Of The Event • How did the accident occur? • How long ago did the accident occur? • Was there loss of consciousness and for how long? • Is there amnesia for the event? • Was there any associated trauma? • Did cardiac arrest occur or was any dysrhythmia recorded?

38. History • Determine if injury was low-voltage ( 600V) or high-voltage ( 600V). • Voltage is one parameter in electrical injury that can be reliably estimated most of the time from the scene. • High-voltage injuries are generally more serious and more likely to involve internal damage. For this reason, if a high-voltage injury is established or suspected, more aggressive fluid resuscitation is required, and triage of the patient may proceed differently than in low-voltage patients.

39. HISTORY If possible, determine the type of electrical source, alternating current (AC) vs. direct current (DC). • A history of DC exposure generally involves a single muscle spasm that throws the victim from the source.The victim has a shorter duration of electrical exposure but increased risk of traumatic blunt injury. • A history of AC exposure generally involves a “no let go” response with tetanic (continuous) muscle contractions, and hence, prolonged exposure to current. Therefore, these injuries are generally much more severe than injuries due to DC and carry high risk of extensive tissue destruction and/or cardiac abnormalities.

40. HISTORY • If possible, determine the mechanism of injury, i.e., direct vs. indirect contact. Knowing the mechanism can help in directing management and/or offering a prognosis. • If the injury was a flash or thermal burn as an indirect result of electric current, internal injuries are unlikely. • If the burn injury resulted from an electrical arc (indirect but striking the body at destructively high temperatures) or from direct contact, the risk of internal injury is high, and greater precautions should be taken.Current flows easily through nerve, blood, and muscle, creating electrical disruption, whereas tissues with higher electrical resistance, such as bone, tendon, and fat, will more likely develop damage from thermal burn injury when exposed to significant electrical current.

41. HISTORY • The patient after an electrical injury is often unable to give a good history, either because of the severity of injury and accompanying shock and hypoxia or because of unconsciousness or confusion that often accompanies less severe in juries. • History from bystanders regarding the type of electrical source, duration of contact, environmental factors at the scene, can be helpful. • Information on prior medical problems, medication history, tetanus immunization status, and allergies should be sought.

42. Rule of nines

43. LOW VOLTAGE INJURIES • Evaluation of low-voltage injuries should include a good history because injury that initially appears to be from a low-voltage source may turn out to have been caused by a discharge from a capacitor (as in the repair of televisions and convection or microwave ovens) or other high-energy source. Although burns from  low-voltage sources are usually less severe than those from high-voltage sources ,patients may still complain of paresthesias for an extended period experience cardiac arrhythmias or develop cataracts if the shock occurs close to the face or head.

44. VASCULAR INJURY • Vascular damage from the electrical energy may be evident early or late Because the arteries are a high-flow system heat may be dissipated fairly well and result in little apparent initial damage but thrombosis with subsequent thrombosis or rupture .Pulses and  capillary refill should be assessed and documented in all extremities, and neurovascular checks should be repeated  frequently.

45. EXTREMITY INJURY • In high-voltage injuries muscle necrosis can extend to sites distant from the observed skin injury and compartment syndromes can occur secondary to vascular ischemia and muscle edema.  Although it is preferable to stabilize the patient prior to transfer to the operating room this is not always possible. • Extremities that have teen burned should be splinted in functional position to minimize edema and contracture formation. electrical injury have been reported.

46. CUTANEOUS INJURY • The most common sites of contact for the current include the hands and the skull. The most common areas of ground are the heels. There may be multiple contact and ground points. • Because high-voltage current often flows internally and can create massive muscle damage one should not attempt to predict the amount of underlying tissue damage from the amount of cutaneous involvement or use the rule of nines for calculating fluid resuscitation. Cutaneous burns should be covered with antibiotic dressings . • Electrical burns are especially prone to tetanus infection and patients should receive tetanus toxoid and tetanus immune globulin on the basis of their immunization history. • A special type of burn from low-voltage injuries is the mouth burns that occur secondary to sucking on household electrical extension cords and are the most common electrical injury seen in children under 4 years of age.

47. HEAD AND NECK • The head is a common point of contact for high volt-injuries and the patient may exhibit burns as well as neurologic damage. • Cataracts develop in approximately 6 percent of cases of high-voltage injuries and should be suspected whenever electrical injury has occurred in the vicinity of the head.Although cataracts may be present initially or develop shortly after the accident. they more typically begin to appear months after the injury. • Cervical spine injury may be caused by a fall or being thrown in either type of injury.

48. DIFFERENTIAL DIAGNOSIS • Electrical injuries are usually self-evident from history and physical surroundings, except in the case of bathtub accidents, where no burns occur, or of foul play. It is necessary to attempt to differentiate between mechanisms of burn injury because flash burns have a much better prognosis than arc or conductive burns. Injuries from blunt trauma and falls may also be present. • The differential diagnosis for lightning injuries is more complex, often because the incident is unobserved . It includes the differential for unconsciousness, paralysis, or disorientation from a number of causes. Evidence- of a thunderstorm or a witness to the lightning strike may not be available. The presence of typical burn patterns, when present, may be helpful.

49. Post-trauma sequelae Crush injury syndrome (rhabdomyolysis, myoglobinuria) Multi-organ ischemic injury Hypovolemic shock Iatrogenic injuries from acute resuscitation Abdominal compartment syndrome ARDS 20 December 2019 49

50. Disposition Hospitalization for in-patient observation or treatmentof electrical injury victims • Hospitalization for cardiac monitoring is suggested. • Hospitalization also is suggested for patients with high-voltage exposure, significant burns, myoglobinuria/myoglobinemia or suspicion of deep tissue damage.