What is the management approach for a patient with low voltage electrical shock in the emergency department?

Management of Low Voltage Electrical Shock in the Emergency Department

Immediate Scene Safety and Initial Assessment

For patients presenting to the ED after low-voltage electrical shock (<1000V), the primary management goal is to identify the rare patient at risk for cardiac complications while safely discharging the majority who have no serious sequelae. 1, 2

Initial Cardiac Evaluation

• Obtain a 12-lead ECG within 10 minutes of arrival to assess for arrhythmias and evidence of cardiac injury 1, 2
• Attach continuous cardiac monitoring immediately upon patient arrival 2
• Assess for any history of loss of consciousness, syncope, or cardiac arrest at the scene 3, 4

Risk Stratification and Disposition

Safe for Discharge Criteria

Patients meeting ALL of the following criteria can be safely discharged after brief ED observation without cardiac monitoring: 3, 4

• Asymptomatic or only minor localized symptoms (e.g., localized pain at contact points) 3
• Normal ECG on presentation 3, 4
• No loss of consciousness at time of injury 4
• Normal vital signs and physical examination 3
• Low-voltage exposure (<1000V) 3, 4

Recent evidence demonstrates that among 210 low-voltage electrical shock patients, none developed serious arrhythmias, elevated troponin T, or died, supporting safe discharge of selected patients 3. A larger study of 465 patients showed 0% 30-day mortality (95% CI 0-0.8%) with no serious arrhythmias detected 4.

Admission Criteria - Require 24-Hour Monitoring

Admit for continuous cardiac telemetry monitoring for at least 24 hours if ANY of the following are present: 1, 2, 5

• Abnormal initial ECG (any rhythm disturbance, conduction abnormality, or ST-T wave changes) 2, 4
• History of loss of consciousness or syncope 4
• Cardiac arrest requiring resuscitation at scene 2
• High-voltage exposure (>1000V) 2, 4
• Chest pain or palpitations 3
• Burns >10% total body surface area 2
• Evidence of deep tissue injury 2
• Concomitant traumatic injuries 2

Laboratory and Diagnostic Workup

For Patients Being Admitted

Obtain comprehensive laboratory panel including: 1, 2

• Complete blood count 1
• Comprehensive metabolic panel with electrolytes 1
• Renal function tests (creatinine) 1
• Creatine kinase (CK) to assess for rhabdomyolysis 4
• Cardiac troponin 4
• Coagulation studies 1
• Capillary glucose 1

For Patients Being Discharged

No routine laboratory testing is required for asymptomatic patients with normal ECG and no loss of consciousness, as troponin elevation (0.6%) and clinically significant CK elevation are extremely rare in low-voltage injuries 4.

Specific Cardiac Management

If Arrhythmias Develop

For unstable monomorphic ventricular tachycardia with pulse: 1, 2

• Use synchronized cardioversion starting at 100 J 1, 2

For ventricular fibrillation or pulseless ventricular tachycardia: 2

• Deliver unsynchronized shocks at 200 J, 200 J, then 360 J in rapid sequence within 30-45 seconds 2

For atrial fibrillation with rapid ventricular response (rare but reported): 6

• Consider synchronized cardioversion at 100 J after analgesia and sedation 6

Standard ACLS Protocols Apply

No modifications to standard ACLS protocols are required for electrical injury victims, except maintaining spinal motion restriction if trauma is suspected 1

Fluid Resuscitation

For patients with significant tissue destruction or burns: 1, 2

• Initiate aggressive IV crystalloid resuscitation with 0.9% normal saline 2
• Administer fluid boluses of 250-1000 mL with reassessment after each bolus 2
• This counteracts shock and facilitates excretion of myoglobin, potassium, and tissue breakdown products 2

Critical Pitfalls to Avoid

• Do not discharge patients with ANY ECG abnormality, even minor changes, as delayed arrhythmias can occur 2, 5
• Do not underestimate injury severity based on visible skin damage alone, as internal tissue destruction is often far more extensive than external appearance suggests 2
• Do not fail to ask specifically about loss of consciousness, as this is a key risk factor requiring admission 4
• Never delay resuscitation to obtain blood samples or perform non-essential assessments 1, 2

Duration of Monitoring

For admitted patients, continue continuous cardiac telemetry monitoring for at least 24 hours, as this is the period during which delayed arrhythmias are most likely to occur 1, 2, 5. The evidence shows that serious complications beyond 24 hours are exceedingly rare in patients who remain stable during initial monitoring 4.