ELECTRICAL INJURIES 2014

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Shonda Charles
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1 ELECTRICAL INJURIES 2014

2 Case 1 31y male electrical worker Working on transformer at substation Arc to R hand holding spanner R elbow grounded by metal fence Alert Flash burns to face

3 Case 2 2y girl Found by parents after loud cry Appliance cord in mouth

4 Case 3 14y male Playing on electrified train track Blown backwards 3 metres Painful R shoulder and lower back

5 Case 4 56y farmer Struck by lightning LOC 4 mins

6 Case 5 60y female Prolonged shock from toaster cord CPR/Defibrillation at scene for VF arrest

7 Case 6 36y male Raising mast on boat Hit overhead suburban power lines LOC and arrest at scene Wounds to R hand and L foot

8 Case 7 40y butcher History of stable angina Short shock to finger from meat grinder Some palpitations initially R hand paraesthesiae Feels a bit shaky

9 Case 8 40y mania and aggression Tasered by police

10 Major Points High v. Low voltage Lightning Taser Injury patterns ED assessment

11 Epidemiology - Australia electrical fatalities per year Low:High voltage ratios approx 3:1 to 7:1 Male, young, summertime Under-reported Home and workplace equal frequency Occupational: linesmen & electricians 3-5% of burns unit admissions Lightning 2-3 deaths per year injuries per year (direct) 60 injuries per year (indirect via telephone line)

Electrocutions in Western Australia 1976-1987 (Fatovich et al) 104

12 Electrocutions in Western Australia (Fatovich et al) 104 victims 95% young men 50% occupational 50% at home 50% involving water

13 Electrical Injuries Depend On: 1. Type of current 2. Voltage 3. Amperage 4. Resistance of tissues 5. Path of circuit 6. Time of exposure 7. Environmental factors

14 1. Types of Current DC Low voltage AC (<600V) High voltage AC Lightning

15 2. Voltage Australia: AC, 230V ( V), 50Hz Worldwide: AC, V, 50-60Hz Tetanic muscle contraction occurs at Hz

16 Power Substation High Voltage Power Lines kV Transmission Substation Power Station 7200V 230V

17 3. Amperage Mill iampere Tingling sensation 1-2 Let-go current Child 3-5 Woman 6-8 Man 7-9 Tetany Respiratory arrest Ventricular Fibrillation

18 Ohm s Law I = V R Current (Amps) = Voltage (Volts) Resistance (Ohms)

19 4. Resistance of Body Tissues Least Intermediate Most Nerves Blood Mucous membranes Muscle Dry skin Tendon Fat Bone

20 Electrical to Thermal Energy P = I 2 Rt Joule s Law The higher the resistance (R) of a tissue to the flow of current, the greater its potential to transform electrical energy to thermal energy (P) at any given current (I)

21 Skin Resistance Ohms/cm 2 Mucous Membrane 100 Wet skin vo lar arm and inner thigh ,000 Bath tub Sweat 2500 Other skin 10,000-40,000 Sole of foot 100, ,000 Calloused palm 1,000,000-2,000,000

22 The Burning Process 10 9 CURRENT Tissue breakdown Carbonisation Series1 3 2 Blistering TIME

23 5. Path of Circuit Trans-cranial pathway LOC/Confusion Trans-thoracic pathway Cardio/Respiratory arrest Arrythmias Transabdominal pathway Foetus Eyes Cataracts

24 Cross-Sectional Diameter Trunk Finger Large therefore decreased resistance Less thermal energy Small therefore large resistance Lots of thermal energy Current concentrations maximum at entry and exit sites

25 6. Time of Exposure AC usually longer (tetany) Prolonged exposure makes any voltage dangerous DC tends to throw person clear Lightning 100 million volts but brief (few milliseconds)

26 7. Immediate Environment Presence of water changes resistance Rain Puddles Bathtub Sweat

27 Types of Circuit Injury Electrical (conductive) injury Vascular Neurological Muscle damage Electro-thermal injury Arcing Electrical Thermal energy within tissue Lightning splash

28 Non-circuit Injuries Flash burns Flame burns Blast injuries Falls Muscular contractions

30 At the Cellular Level: Thermal damage Direct transmembrane potential changes Depolarisation Electroporation Ca 2+ in, K + out

31 Cardiac Asystole / VF arrest at time of electrocution Sinus tachycardia Transient ST elevation Increased QT PVCs AF Reversible bundle branch block Acute myocardial infarction is rare

32 Respiratory Respiratory arrest At medulla From tetany of diaphragm or chest wall Generally lungs are spared from direct electrical injury ARDS, blast injuries, smoke inhalation

33 Nervous System Coagulative necrosis of nerves Intracranial bleeds Hypoxic damage Trauma LOC common and transient Often confused and problems with STM and concentration

34 Spinal Cord Trauma Immediate or delayed non-traumatic cord injury Weakness and paraesthesia Lower > upper limbs Delayed for years Ascending paralysis ALS or transverse myelitis

35 Soft tissues Muscle near bone more extensively burnt Can appear unaffected initially Damage can be progressive Compartment syndrome

37 The Hidden Injury

38 The Hidden Injury

39 Vascular Initial intense vascular spasm Greatest damage to tunica media Internal damage causes delayed thrombosis Progressive necrosis of various tissues More marked in slow blood flow areas Veins more likely to be affected - oedema Delay in vessel breakdown and haemorrhage

40 Organ Dysfunction Result of current Result of low flow state Result of pigment release or infection Cardiac arrest Sepsis Renal Damage CNS injury Pulmonary dysfunction

41 Rhabdomyolysis Indicative of severe muscle damage Venous obstruction High iv fluid requirement +/- Mannitol Urine ph >7

42 Skin Most common entry site head, hands May appear as painless depressed yellow-grey area Can have underlying burns - iceberg phenomena

43 Flash Burn Non-conductive Superficial Difficult to distinguish on history from arctype burns

44 Arc Burns Most destructive Between 2 objects at different potentials but not connected Usually highly charged source and ground Temperatures around 2500 degrees Celsius Deep burns May cause secondary thermal burns from ignition of clothes Kissing burns

46 Deep Thermal Burn

47 Contact Burns Conductive burn Dermal appendages left intact

50 Typical High Voltage Entrance Site

52 Typical High Voltage Exit Site

53 Explosive Exit Wounds

57 Child bites electrical cord

58 Oral Burns Saliva Local arc burn Temp up to degrees Celsius Usually no systemic problem Delayed haemorrhage of lingual artery Scarring / contractures

61 Other Opthalmic complications Ears Viscera - rare Wound infection Stress ulcers

62 ED assessment Majority will be relatively well Primary and secondary survey ECG Pregnancy FHM, USS, obstetric r/v

63 Initial Treatment of High Voltage Injuries Make the Diagnosis ABC Treat as likely C-spine injury Consider possibility of muscle necrosis (look for exits) Presence of blunt traumatic injuries Size and depth of skin burn

64 Who should have cardiac monitoring? Patients require cardiac monitoring if: Cardiac arrest Documented LOC Abnormal ECG Arrythmia observed pre-hospital or in ED History or high risk of cardiac disease Other severe injury needing admission Hypoxia Chest pain

65 Soft tissue damage Manage as a crush injury rather than as a burn. Volume replacement there will be large exudation and sequestration of fluids Parkland formula does not apply. Treat acidosis Treat rhabdomyolysis Maintain urine > 1mL/kg/hr Maintain urine ph >7 (add HCO3 to fluids)

66 Infection Tetanus prophylaxis Antibiotic prophylaxis Wound dressings Debride when stable

67 Perfusion Vascular observations Compartment pressures Fasciotomy/Escharotomy

68 Lightning 100 million volts 200,000 A Few milliseconds Kills more than hurricanes and tornadoes combined Second only to floods as an environmental killer

69 Lightning Mortality from direct strike up to 30% Higher rate of foetal death If survive, probability of long term impairment is low Most unwitnessed, diagnosis can be difficult Historical clues Physical exam clues

70 Lightning injury is not the same as high-voltage injury Factor Lightning High-voltage Time of exposure Brief instantaneous Prolonged tetanic Energy level 100,000,000 V 200,000 A Usually much lower Type of current Direct Alternating Shock wave Yes No Flashover Yes No Lightning victims almost never require acute treatment with high volume IV fluids, debridement, fasciotomies, or alkalinisation/diuresis.

71 Types of Strike Direct Side flash Step voltage

72 Struck flag pole and dispersed

73 Presentation Usually rendered unconscious On first regaining consciousness they may be mute and unable to move for a few minutes. This can last up to 24 hours. Most behave as if they have had ECT or a severe concussion, with confusion and amnesia for several days Asystolic cardiac arrest May revert quickly Can be followed by secondary hypoxic arrest

74 Cutaneous Findings Present in 90% Entry / exit wounds rarely seen Ferning or feathering 20% Fades within hours Deep burns Only when skin in contact with metal (e.g. keys) Punctate burns 1mm-1cm Linear lines Steam burns on sweat lines

75 Lichtenberg figures

76 Courtesy of National Lightning Safety Institute

77 All sorts of injuries possible Burns Chest pain and muscle aches Contusions from shockwaves Intracerebral haemorrhage Brain may coagulate Skull # possible Perforated TMs / sensorineural deafness Retinal detachment / optic nerve damage Delayed cataracts

78 Cardiac Cardiac arrest Usually initial asystole 25-50% survival rate if CPR by bystanders In 75% of all direct strike victims 55% of all victims Other Delayed arrhythmia and MI rare Any type of ECG change Apnoea may be prolonged but is not a poor prognostic sign

79 Keraunoparalysis Intense vascular spasm of limb Flaccid paralysis Complete loss of sensation Impalpable pulses Mottled / pale / blue appearance Self-limiting usually resolves spontaneously within hours

80 Neurological Any deficit possible Common: LOC Lower extremity paralysis Confusion Amnesia Seizure Hemiplegia Tinnitus

81 Standard trauma management ABCs C-spine ECG Full survey Normally less underlying tissue damage Treat symptomatically

82 Avoid the following Open Fields 45% Under Trees 23% Water 13.6% Golf 6.5% Farm / Heavy Equipment 5% Telephone 4% Golf and Trees 1.7% Radio Equipment 1.2%

83 Relative Lightning Protection Safe Locations Lightning Certified Facility Lightning Protected Building House Car Outdoors

84 Tasers meh.

ELECTRICAL INJURY 9/21/2015 I HAVE NO DISCLOSURES WE HAVE OBTAINED APPROVAL FOR USE OF IDENTIFIABLE PATIENT PHOTOS

ELECTRICAL INJURY 9/21/2015 I HAVE NO DISCLOSURES WE HAVE OBTAINED APPROVAL FOR USE OF IDENTIFIABLE PATIENT PHOTOS ELECTRICAL INJURY SAMUEL P. MANDELL, MD, MPH ASSISTANT PROFESSOR OF SURGERY UNIVERSITY OF WASHINGTON SEPTEMBER 28, 2015 I HAVE NO DISCLOSURES WE HAVE OBTAINED APPROVAL FOR USE OF IDENTIFIABLE PATIENT PHOTOS