Electrical Injuries

1. Electrical Injuries http://www.carldbarnes.com/Practiceareadescriptions6.aspx Author: Anna Macdonald, MD Date Created: July 2012 http://www.youthedesigner.com/2010/11/30/photos-of-lightning-30-electrifying-examples/

2. Learning Objectives • To understand some basic pathophysiology behind electrical injuries • To describe the clinical features of electrical injuries • To review prehospital and ED management • To highlight unique features of lightning injuries

3. Case • A 35 year old male electrician • Was repairing some wiring at a construction site and observed by coworkers to be thrown off of scaffolding and lost consciousness briefly • On arrival patient is awake and complaining of severe bilateral arm pain • HR 120, BP 140/80, RR 24, O2 98% RA • You see burns to both hands • What are your management priorities?

4. A quick physics lesson • Joule’s Law • P = I2Rt • P is heat (joules) • I is current (amps) • R is resistance (ohms) • t is time (sec) • Ohm’s Law • I = V/R • V is voltage • Hence severity of injury is determined by: • Voltage, resistance of tissue, time in contact with current

5. A little more physics • Direct Current versus Alternating Current • DC: • Single muscle contraction • Throws victim away from source • Sources: batteries, high voltage power lines, lightning • Usually causes visible burns at entry/exit sites • AC: • Tetanic contraction • Prolongs contact with source hence more dangerous • Sources: most homes and offices • May not cause discernable burns at entry/exit sites

6. Electrical injury • Injury by 3 mechanisms • Injury from current flow (direct contact) • Arc injury (electricity passes through air) • Electricity arcs at a temperature of 4000C, causing flash burns • Flame injury by ignition of clothing or surroundings

7. Types of electrical injury Electrical injury Arc Injury (flash burn type injury) High voltage (>1000V) Low voltage (<1000V) Lightning

8. Electrical arc http://guides.wikinut.com/img/138a.2js40g7r7_o/Electrical-arc (accessed Sept 2012)

9. Comparing the different types

10. High voltage versus low voltage • High voltage (>1000V) injuries tend to have higher rates of complications • Amputations, fasciotomies • Compartment syndrome • Longer hospital stays, ICU stays, mechanical ventilation • Cardiac dysrhythmias, acute renal failure • Higher body surface area burn

11. Injury distribution • In adults, injuries tend to be occupational and high voltage • In children, injuries appear bimodal • Young children < 6y tend to have low voltage injuries from the household • Adolescents and older children tend to have high voltage injuries from playing near high-tension lines

12. Resistance of tissues • Low • Nerves • Blood • Mucous membranes • Muscle • Intermediate • Skin (resistance will be reduced by moisture) • High • Tendon • Fat • Bone http://rrtelite.50webs.com/faid_electricshock.html

13. Pathway • Path that current takes through body determines: • Which tissues are at risk • Across thorax  cardiac damage/dysrhythmias • Across head  seizures, resp arrest, paralysis • Severity of damage • Less damage with less current density • Current through trunk will cause less damage than through a digit • Shorter distance between contact points will cause less damage • Child chewing on electrical cord <<< same voltage with head to toe pathway

14. Clinical features • Head and neck • Tympanic membrane rupture • Temporary hearing loss • Cataracts – may happen immediately or be delayed • Cardiovascular system • Dysrhythmias – asystole, VF  cardiac arrest • May also cause transient ST elevation, QT prolongation, PVCs, Atrial fibrillation, bundle branch blocks

15. Clinical features • Skin • Thermal burns at contact points • Kissing burn – current causes flexion of extremity  burns at flexor creases • Burns around mouth common in children who chew on electrical cord • * Careful with these as separation of eschar can cause delayed bleeding of labial artery http://www.forensicmed.co.uk/wounds/burns/chemical-and-electrical-burns/ (accessed July 2012) Rosen’s Emergency Medicine. Chapter 140 page 1897 -see references at end of presentation for full reference

16. Clinical features • Extremities • Compartment syndrome – requires fasciotomies • Damaged muscle  massive release myoglobin  rhabdomyolysis  renal failure • Vascular • Thrombosis of vessels • Damage to vessel walls  delayed rupture and hemorrhage • Skeletal system • Fractures/dislocations from trauma or from tetanic muscle contractures (e.g. shoulder dislocations)

17. Clinical features • Nervous system • Brain • Loss of consciousness (usually transient) • Respiratory arrest • Confusion, flat affect, memory problems • Seizures • Spinal cord injury either immediate or delayed • Peripheral nerve damage

18. Electrical burn - fasciotomy http://burnssurgery.blogspot.ca/2012/07/electrical-contract-burns-bilateral.html#!/2012/07/electrical-contract-burns-bilateral.html (accessed Sept 2012)

19. Electrical injury - amputation http://www.emedicinehealth.com/electric_shock/page10_em.htm (accessed Sept 2012)

20. Electrical injury http://med.brown.edu/pedisurg/Brown/IBImages/Trauma/oralburn.html (accessed Sept 2012)

21. http://www.wefixwires.com/new_page_2.htm (accessed Sept 2012)

22. Out of hospital management • Ensure scene safety • Careful for live lines on the scene • ACLS protocols as needed • Fluid resuscitation with saline or ringers lactate • Spine immobilization if suspected trauma

23. ED assessment • History • AMPLE history • Details of the electrical source • LOC on scene • Prehospital interventions • Physical exam • Primary and secondary surveys as in ATLS • Look carefully at every inch of skin for entry/exit wounds

24. ED initial management • ABCs, ACLS, trauma management as needed • Fluid resuscitation • Parkland formula not helpful here as surface wounds not reflective of more extensive internal damage • Titrate to urine output 0.5-1 cc/kg/hr • ECG • Analgesia!

25. Cardiac monitoring Low voltage injury < 1000 V Loss of consciousness or Documented dysrhythmia Normal ECG or Abnormal ECG Discharge home Admission with telemetry High risk patients Low risk patients

26. Cardiac monitoring • But... High voltage injury > 1000 V Normal ECG ?? Intermediate risk patients

27. Other cardiac issues • Time of monitoring not known – usually up to 24 hours, but data limited • CK-MB may not be accurate at diagnosing cardiac injury

28. Wound care • Tetanus immunization • Dress wounds – may use antibiotic dressing like silver sulfadiazine or clean, dry dressings • No role for prophylactic systemic antibiotics

29. Rhabdomyolysis • Check CK – measure of muscle injury, risk of amputation, length of hospitalization • Check urine for myoglobin (or assume presence if urine is heme pigmented) • Goal is to prevent renal failure • Fluids to maintain urine output 1-1.5 cc/kg/hr • Bicarb? Lasix? Mannitol? • No evidence to prove any of these are helpful

30. Extremity injury • Monitor for compartment syndrome • Feel compartments, assess for pain on passive extension, paraesthesias etc • Compartment pressures should be < 30 mmHg • Fasciotomy if needed • May need carpal tunnel release if arm involvement • Amputate non viable extremities/digits • Splint in position of safety to prevent contractures

31. Position of safety • 35-40 degree extension of wrist • 80-90 degree flexion of MCPs • Almost full extension of PIP/DIPs https://www2.aofoundation.org/wps/portal/!ut/p/c0/04_SB8K8xLLM9MSSzPy8xBz9CP0os3hng7BARydDRwN39yBTAyMvLwOLUA93I4MQE_2CbEdFAF3RnT4!/?segment=Thumb&bone=Hand&soloState=true&popupStyle=diagnosis&contentUrl=srg/popup/further_reading/PFxM2/78/78-5-postop_treat.jsp (accessed July 2012)

32. Incidence of injuries in all-comers in one study - Maghsoudi 2007 • Fasciotomy – 1.5% • Escarotomy – 3.5% • Amputation – 7.4% • Skin grafting – 37.6% • Renal failure – 0.5% • Myoglobinuria – 9%

33. Incidence of injuries in high voltagein another study – Arnoldo 2004 • Fasciotomy – 33.4% • Escharotomy – 4.5% • Amputation – 36% • Renal failure – 2.6% • Cataract – 2% • Cardiac arrest – 1%

34. Disposition • Admit if: • Needs cardiac monitoring (at least 12-24 hrs) • Pregnant patient (for fetal monitoring) • Other injuries (trauma) severe enough to warrant admission • Significant burns (consider transfer to burn center • Most high voltage injury

35. Electrical injury summary • ABCs, ATLS • Dysrhythmias – ACLS • Manage trauma and orthopedic injuries • Consider need for amputations, fasciotomies, escharotomies • Consider myoglobinuria and rhabdomyolysis • Splinting, burn and wound care • Consider need for cardiac monitoring • Abnormal ECG, dysrhythmia, loss of consciousness, high voltage injury • Consider transfer to burn centre

36. Lightning injuries – clinical features • Special case as is a massive current impulse for a very short time • Short time duration means minimal burns, tissue destruction • Main cause of death is cardiac arrest • Higher mortality than other electrical injuries http://www.moonraker.com.au/techni/lightning-marine.htm (accessed July 2012)

37. Lightning injuries – injury pattern • Cardiac • Usually asystole instead of Vfib • ENT • Perforated tympanic membranes, displacement of ossicles • Cataracts (often delayed) • Psychiatric • PTSD, depression, chronic fatigue

38. Lightning injuries continued... • Neurologic • LOC, confusion, anterograde amnesia, paraesthesias • Keraunoparalysis – transient paralysis of lower limbs (sometime upper) that are cold, mottled, blue and pulseless – usually self resolves in few hours

39. Lightning injuries • Sometimes lightning injuries cause multiple casualties • Lightning victims may be: • Apneic (from paralysis of respiratory control centre) • Pulseless (cardiac standstill) • Dilated pupils from autonomic dysfunction • And should notbe triaged as per usual mass casualty triage

40. Lightning injuries - burns • 4 patterns of burns • Linear • Punctate • Feathering • Thermal http://www.scienceinseconds.com/blog/By-the-Power-of-Zeus (accessed July 2012) http://atlas-emergency-medicine.org.ua/ch.16.htm (accessed July 2012) http://atlas-emergency-medicine.org.ua/ch.16.htm (accessed July 2012) Feathering Punctate Linear

41. Lightning injuries - management • ECG • Cardiac biomarkers if ECG abnormal, chest pain, altered mentation • CT head if altered mentation • Does not usually require aggressive fluid resuscitation, fasciotomies etc

42. Long term sequelae • Numbness, Weakness • Memory problems • Anxiety, depression, insomnia • Nightmares • PTSD

43. Long term sequelae • High voltage injuries also tend to have higher rates of… • Neuropathic pain • Neuropsychiatric symptoms • PTSD …Than low voltage injuries

44. Back to the Case • A 35 year old male electrician • Was repairing some wiring at a construction site and observed by coworkers to be thrown off of scaffolding and lost consciousness briefly • On arrival patient is awake and complaining of severe bilateral arm pain • HR 120, BP 140/80, RR 24, O2 98% RA • You see burns to both hands • What are your management priorities?

45. Case • ABCs • Awake and talking, breathing comfortably • 2 large bore IVs to give 2L bolus normal saline • Don’t forget spine precautions and c-collar • Cardiac monitor and ECG • Examine (and manage) as you would a trauma patient given history of fall • Analgesia • Follow urine output to guide fluid therapy (at least 0.5-1 cc/kg/hr or 1-1.5 cc/kg/hr if rhabdomyolysis)

46. Case • Tetanus immunization, dress wounds • Send labs including CK and urine for myoglobin • Extremities (arms in this case) • Neurovascular exam • Assess for compartment syndrome – call surgeon if needs fasciotomies or carpal tunnel release • Admit to ICU setting

47. Quiz Question 1 • Name 5 things that affect the severity of electrical injury: • Type of circuit (AC vs DC) • Duration of contact with circuit • Resistance of tissues • Voltage • Amperage • Pathway of current through body

48. Quiz Question 2 • How do you best fluid resuscitate a patient with electrical injuries? • Use the Parkland formula • Use the rule of nines • Titrate to urine output 1-1.5 cc/kg/hr • Give 1 litre bolus

49. Quiz Question 3 • Name 6 indications for inpatient cardiac monitoring in electrical injuries? • Cardiac arrest • History of loss of consciousness • Abnormal ECG • Dysrhythmia observed • History of cardiac disease or significant risk factor for cardiac disease • Suspicion of conductive injury • Hypoxia • Chest pain • High voltage injury (>1000 V)

50. Quiz Question 4 • How do you treat rhabdomyolysis? • Fluids to maintain UO of 0.5-1 cc/kg/hr and sodium bicarb • Fluids to maintain UO of 1-1.5 cc/kg/hr and sodium bicarb • Fluids to maintain UO of 0.5-1 cc/kg/hr • Fluids to maintain UO of 1-1.5 cc/kg/hr