Wednesday Wrap-up: EM Critical Care Conference June 2013

Thanks to Dr. Regan for putting together this summary of our last EM Critical Care conference!

The Case: Man found unresponsive underneath subway train with right hip dislocation, electrocution by third rail, multiple burns and rhabdomyolysis.

Electrical Injuries

Voltage:

-High voltage is >1000, low voltage is <1000

-Outlets in U.S. homes have 100V, European home 220V

-Power lines > 100,000 V, Lightning >1 million V

Direct Current (DC):

-travels in one direction

-used in 3^rd rail in subway and batteries

Alternating Current (AC):

-periodically reverses direction

-can cover longer distances than DC

-used in appliances, car motors, radio towers

-is more dangerous than DC at the same voltage (tetanic contraction in DC tends to throw the person away from the source)

Electrocution Injuries:

-Cardiac:

15% incidence of arrhythmias, Vfib most common cause of fatal arrhythmia
necrosis of myocardium
DC/lightning cause asystole, AC causes Vfib

-Renal:

acute renal failure
rhabdomyolysis: treat with bicarb drip to alkalinize urine

-Neuro:

both central and peripheral nervous systems can be affected
LOC, weakness, respiratory depression, autonomic dysfunction, sensory & motor findings

-Derm:

degree of external injury does not correlate with internal injuries
all types of burns
pediatric oral burns: watch for bleeding from labial artery injury; all should be referred to plastic surgery for follow-up

-MSK:

bone generates greatest amount of heat–>periosteal burns, osteonecrosis
tissue necrosis can lead to compartment syndrome
traumatic injuries from blunt trauma (especially lightning and high voltage DC), ie: joint dislocations

-Other:

tympanic membrane rupture
cataracts
in lightning injuries, respiratory arrest due to tetanic muscle contraction (reverse triage is important in these patients)

Disposition:

-Low voltage (i.e. house): no cardiac complaints and normal EKG can be safely discharged

-High or Low voltage with significant injuries

treat burns, consider transfer to burn center if necessary
treat associated blunt traumatic injuries
in asystolic arrest, secure airway with ACLS. ROSC is common.

References

Browne BJ, Gaasch WR. Electrical injuries and lightning. Emerg Med Clin North Am. 1992 May; 10(2): 211-29.
Koumbourlis AC. Electrical Injuries. Crit Care Med. 2002;30(11 Supp):S424-30.
Lee RC. Injury by electrical forces: pathophysiology, manifestations and therapy. Curr Probl Surg. 1997 Sep:34(9): 677-764.
Rabban J, Adler J, et al. Electrical injury from subway third rails: serious injury associated with intermediate voltage contact. Burns. 1997 Sep;23(6): 515-8.
Wright RK, Davis JH. The investigation of electrical deaths: a report of 220 fatalities. J Forensic Sci. 1980 Jul;25(3): 514-21.