Electrical Injuries: Hertz So Bad

Victims of electrical injuries present either in extremis or as the seeming well patient with insidious, developing disease.

A targeted history usually gets you the information you need.

 

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Four main things to find out:

1. Household or Industrial electricity?

Household electricity uses alternating current, or AC.  Voltages across the world range anywhere from 100 to 240 V.  Here in North America, most outlets and appliances use 120 volts, which is the measure of electrical tension, or the potential difference in electrical charge.

Cut-off between low voltage and high voltage is 1000 V.

Industrial energy may be AC or direct current, DC.  DC current propels the victim -- think of this as a blast injury.  The same voltage in AC is three times as damaging as that voltage at DC, because AC causes muscle tetany, and prolonged contact time.

2. What was the likely pathway that current took?

Did the current pass through the thorax?  -- Think dysrhythmias.  Through the head or neck?  -- Think damage to the CNS and risk for later central respiratory arrest; acoustic nerve damage; cataract formation.  Did the current pass along an extremity? -- Think compartment syndrome and rhabdomyolysis.

3. What was the contact time?

The electrical charge meets resistance and converts to thermal energy, which causes tissue necrosis, increasing with the contact time.  Was your patient extricated?  Was there tetany?  Was he found in a pool of water or liquid?  Longer contact time correlates with extensive injuries that may only be apparent hours later.

4. Are there any associated injuries?

Think of electrical injury as a trauma – major trauma rarely occurs in isolation.   Was the patient flung after contact?  Did he have a syncopal episode? -- Think precipitated dysrhythmia and fall.   Was there any chest pain?   -- Consider stress-induced ischemia.

 

Pearl: Patients may be confused initially or unable to localize symptoms because of CNS disruption.  Get collateral information, re-interview, and re-examine as needed.

 

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 Case 1: Toddler with an oral commissure burn

An electrical burn to the angle of the mouth cauterizes superficial bleeding vessels, and hours later the wound becomes covered with a white layer of fibrin, surrounded by erythema.  Edema and thrombosis will continue, and at 24 hours there is typically a significant margin of tissue necrosis.  Most patients do well, and the burn heals by secondary intention.  The eschar will slough off in 1 to 2 weeks.  The labial artery is just deep to the burn, and as the eschar sloughs off, it can be exposed.  It’s a high-flow artery to the face, and if disrupted, the child may have significant bleeding and possibly hemorrhagic shock.

These children need close wound care follow-up, and potentially outpatient coordination with Head and Neck Surgery and/or Plastic Surgery consultants.

Precautionary advice:  take the moment to talk to parents about the risk, and show them how to apply pressure to the wound, pinching the inner and outer cheek together with the thumb and index finger until the child arrives to the hospital.

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Case 2: School-age child with knife versus electrical outlet

A a “kissing burn” occurs when the electrical charge creates an arc and jumps to a more proximal portion of the extremity.

The kissing burn typically occurs at flexor creases such as the wrist or the antecubital fossa.  There is often extensive underlying tissue damage even under the skin where it doesn’t appear to be involved.  Compartment syndrome and subsequent rhabdomyolysis and renal failure are the highest-risk complications.

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Case 3: Adolescent after a taser exposure

Nitrogen capsules propel two barbs into the dermis, which deliver short bursts of energy; most patients have no harm from the electricity delivered.

How to remove a dart:  The darts are typically 9 mm long, but the small barb is typically not buried very deep in the skin.  Hold the skin taught, use a hemostat to grasp the end as close to the skin as possible, align the dart perpendicularly to the skin, and pull quickly and firmly.

If the patient can’t tolerate this or the barb appears particularly embedded, inject with local lidocaine and make a small superficial incision with an 11-blade scalpel just large enough to allow passage.   Ultrasound can be used to troubleshoot when needed.

Taser dispo:  People who have been tased do remarkably well and complications are rare.   In a review of tasers used by law enforcement, Vilke et al. found that there was no need for routine laboratory testing or observation, as there was ‘no evidence of dangerous laboratory abnormalities, physiologic changes, or immediate or delayed cardiac ischemia or dysrhythmias after exposure to electrical discharges of up to 15 s.”  Subsequent studies with minors less than 16 years of age found similar results.

Special note on the patient with agitated delirium or stimulant intoxication: treat these patients carefully, as the organic problem that got them tased in the first place still needs to be addressed, and substances such as PCP, cocaine, and methamphetamines are all cardiac irritants and may predispose them to dysrythmias.

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Case 4: Adolescent in full arrest after lightening strike

Patients who are struck by direct current like lightening should be treated aggressively, because the reason for their cardiac arrest is often reversible if treated quickly.  Either the current sent the victim into a dysrhythmia, or it caused a temporary paralysis of the thoracic muscles, resulting in a primary respiratory arrest.

For victims of a lightning strike, classically we use reverse triage – normally, those in full arrest are triaged as black, deceases.  In high-voltage and lightening injuries, we tend to those in full arrest first, because you might quickly reverse them, and can move on to the next patient triaged red, or immediate.

High-voltage injuries are a multi-trauma – other sequelae include pulmonary edema, paralysis, ileus, and cataracts, in addition to the more immediate cardiac, musculoskeletal, neurologic, and renal considerations.

Regardless of the exposure, obtain an ECG and look for bundle branch block, heart block, and dysrhythmias, since those will change disposition.  In those who are injured, consider a basic metabolic panel, looking for potassium, calcium, and creatinine.  A creatine phosphokinase or total CK will screen for rhabdomyolysis.  Troponin is not predictive of the extent of direct myocardial damage, but get it if you think there might be a stress-induced, or type II MI.  Radiography as needed depending on the presenting associated trauma.

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Take Home Points

1. Injury from electrical burns can be subtle.   Think of patients as having occult multi-trauma.   Be thorough in history and examination.  Plan to re-examine either during observation in the ED, or in close outpatient follow-up.

2. Discharge patients with low-voltage injury, no symptoms, and a normal ECG.  Counsel outpatients and provide close follow-up as appropriate.

3. Admit patients with low-voltage injury with signs or symptoms such as loss of consciousness, ECG changes, or evidence of end-organ damage on laboratory screening.  Admit all patients with high-voltage injury, even if asymptomatic and a normal laboratory screen.

4. Transfer patients with high-voltage injury or significant burns to a regional burn center or trauma center.

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References

Celik A, Ergün O, Ozok G. Pediatric electrical injuries: a review of 38 consecutive patients. J Pediatr Surg. 2004;39(8):1233-1237.

Ericsson KA. Deliberate Practice and Acquisition of Expert Performance: A General Overview. Acad Emerg Med. 2008; 15:988-994.

Fish RM. Electric injury, part I: treatment priorities, subtle diagnostic factors, and burns. J Emerg Med. 1999;17(6):977-983. doi:10.1016/S0736-4679(99)00127-4.

Fish RM. Electric injury, part II: Specific injuries. J Emerg Med. 2000;18(1):27-34. doi:10.1016/S0736-4679(99)00158-4.

Fish RM. Electric injury, part III: cardiac monitoring indications, the pregnant patient, and lightning. J Emerg Med. 2000;18(2):181-187. doi:10.1016/S0736-4679(99)00190-0.

Horeczko T. “Electrical Injuries: Shocking or Subtle?” In Avoiding Common Errors in the Emergency Department, 2nd Edition. Mattu M, Swadron SP (eds). Lippincott, Williams & Wilkins. Phiadelphia. 2016. (In Press).

Rai J, Jeschke MG, Barrow RE, Herndon DN. Electrical Injuries: A 30-Year Review. J Trauma Acute Care Surg. 1999;46(5):933-936.

Vilke GM, Bozeman WP, Chan TC. Emergency department evaluation after conducted energy weapon use: review of the literature for the clinician. J Emerg Med. 2011; 40(5):598-604.

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This post and podcast are dedicated to Joelle Donofrio, MD, FAAP for her tireless care of children, in the ED and in the field.  A special thank you and dedication to Cliff Reid, BM, FRCP(Glasg), FRCSEd(A&E), FRCEM, FACEM, FFICM, FCCP, EDIC, DCH, DipIMC, RCSEd, DipRTM, RCSEd, CCPU, CFEU for his transformative intelligence and educational verve.