Epidemiology
- 3 primary age groups
o Toddlers – household sockets, appliances, etc.
o Adolescents – risk-taking behavior
o Adults – occupational hazard
- Lightning strikes – account for 50-300 deaths per year in US (mostly Florida)
- ~6,500 injuries and 1,000 deaths annually from all electrocution injuries
Classification
- Low voltage: ≤1000 volts (V)
o Household outlets in US typically 120 V
- High Voltage: >1000 V
o Power lines > 7000 V
- Alternating current (AC) = electrical source with changing direction of flow household outlets
o Induces rhythmic muscle contraction tetany prolonged electrocution as individual is locked in place
o Although generally lower voltages, can be more dangerous than DC as the time of electrocution is much higher
- Direct Current (DC) = electrical source with unchanging direction of current of flow lightning strikes, cars, railroad tracks, batteries
o Usually induces a single, forceful muscle contraction can throw an individual with significant force higher risk of severe blunt trauma
Mechanisms of Injury
- Induced muscle contraction rhabdomyolysis
- Blunt trauma
- Burns
o Internal thermal heating – most of damage caused by direct electrocution
o Flash/Arc burns – electricity passes over skin causing external burns
o Flame – electricity can ignite clothing
o Lightning strikes can briefly raise the ambient temperature to temperatures greater than 54,000F
Severity of Injury – is determined by…
- Type of current – AC vs. DC
- Duration of contact
- Voltage
- Environmental circumstances (rain, etc.)
Clinical Manifestations
- Cardiac – 15%, mostly benign and occur within few hours of hospital stay
o Arrhythmias - Most occur shortly after the event, though non-life-threatening arrhythmias can occur a few hours after the event and are usually self-resolving. Generally, …
§ DC = asystole
§ AC = ventricular fibrillation
o Other EKG findings – QT prolongation, ST elevations, bundle branch blocks, AV blocks, atrial fibrillation
- Pulmonary
o Respiratory paralysis – diaphragmatic muscle
o Blunt trauma – pneumothorax, hemothorax, pulmonary contusions, etc.
- Neurologic – generally, patient can APPEAR DEAD but is the cause of neurologic electrocution and may be temporary. IE.
o Coma
o Fixed, dilated pupils
o Dysautonomia
o Paralysis or anesthesia
- Renal – Rhabdomyolysis
- Skin – All kinds of burns
- MSK – from severe muscle contractions
o Always assume C-spine injury
o Compartment syndrome
o Fractures/Dislocations
Management – we’ll divide them into categories of severity. Basically, always do an EKG!!
1) Mild (<1000V) – examples include brief house outlet shock, stun gun
a. EKG – other work-up such as troponin and CPK usually unnecessary
b. If history/physical unremarkable (patient endorses brief contact with house outlet) patient can be discharged without further work-up
c. If PMH puts patient at higher risk of arrhythmia (cardiac disease, sympathomimetics) can do a brief period of telemetry observation
d. Can always observe 4-8 hours to be on the safe side
e. High Risk Features
i. Chest pain
ii. Syncope
iii. Prolonged exposure
iv. Wet skin
2) Severe Electrocution (>1000V) – industrial accidents, lightning strikes
a. Coding – pursue usual ACLS
i. Keep in mind traumatic causes of arrest (tension pneumothorax, etc.)
ii. KEY FACT: remember that patients with fixed, dilated pupils, no respiratory effort, and no spontaneous movement may only have TEMPORARY neurologic stunning
iii. Pursue resuscitation longer than usual as patient with ROSC can still have good outcomes does not appear to be any definitive guidelines on when to terminate, at physician discretion
b. Otherwise, broad medical and traumatic work-up and likely admission for telemetry monitoring (basically just send all the labs and images)
i. Start with primary/secondary trauma survey and further imaging as required
ii. Don’t forget CPK to assess for rhabdomyolysis
c. Consider transfer to burn center
TL;DR
- Treat as you would a trauma/burn patient
- Most household outlet shocks – history/physical, EKG, and likely quick discharge unless high risk features
- Industrial shocks – at best admit for telemetry. At worst prolonged ACLS as good outcomes are possible. Don’t forget traumatic causes such as tension pneumothorax
http://brownemblog.com/blog-1/2020/4/14/acute-care-of-the-electrocuted-patient
http://www.emdocs.net/electrical-injury/
http://www.emdocs.net/em3am-electrical-injuries/
http://www.emdocs.net/em-cases-electrical-injuries-the-tip-of-the-iceberg-view-larger-image/
https://www.tamingthesru.com/blog/air-care-series/electrocution