Pocket Emergency Medicine (Pocket Notebook Series) 3rd Ed.

ELECTRICAL INJURY

Background

• Current: Measure of amount of energy flowing through an object; in amperes (A)

Approach

• Early & continuous cardiac monitoring for dysrhythmias

• Evaluate for concomitant trauma (fall, injury); maintain c-spine precautions

• Divided in low voltage <500 & high voltage

History

• Usually obvious & reported (eg, occupational injury of electrician, home handyman); pt reports minor shock (tingling) related to home appliance use

• “3rd rail” contact from light-rail mass transportation system

• Toddler w/ burns to corners of mouth (chewing) or hands (playing w/ socket)

• Bimodal distribution w/ most pts <6 or adult workers

Findings

• VF more common w/ low voltage AC, asystole w/ high voltage AC or DC

• Respiratory arrest via chest wall paralysis or respiratory center of brain possible

• Skin wounds may appear minor & entry/exit wounds may be present (examine bottoms of feet for exit); may be more severe than they appear due to deep-tissue injury

• Long-bone fx, scapular fx, shoulder dislocation, spinal fx from mechanical trauma caused by whole body tetanic contractions or trauma of being blown back

• Perforated TMs, delayed cataracts in 6% of pts

Evaluation

• ECG, CBC, Chem 7, cardiac enzymes (rhabdomyolysis), UA (myoglobin)

Treatment

• Resuscitate, eval for trauma, immobilize c-spine, continuous cardiac monitoring

• High-volume IV crystalloid (NS)

• Urinary catheter placement: Target urine output: 0.5–1 mL/kg/h

• If rhabdomyolysis (↑ CK, +UA dip), maintain high UOP until urine dip negative

• Goal serum pH 7.45–7.55

• Alkaline urine (pH > 6.5) to ↑ excretion of acidic myoglobin by ↑ solubility; D5W + 150 mEq NaHCO3 OR D5 ¼ NS or D5 ½ NS + 100 mEq NaHCO3

• Diuresis w/ Lasix 20–40 mg IV or mannitol 25 g IV (then 12.5 g/kg/h) prn

• Treat wounds the same as thermal burns (10 d)

• Compartment pressures ± fasciotomy if sx of compartment syndrome

• Splint injured extremities in best “position of fxn” to minimize contractures

Disposition

• If asx & nl exam, can be discharged

• If mild cutaneous burns & nl ECG, nl urine dip, observe for 2 h, then d/c

• ECG Δ, myoglobinuria, entry/exit burns, partial/full thickness burns: Admit burn center

Pearls

• Electrical injuries are often minor, but may be more serious than they 1st appear. If any concern, observe for 6–12 h.

• Pediatric oral “bite” burns may develop delayed labial artery bleed at 2–3 wk



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