Electrical Injuries
Michal Maimon
Introduction
Electrical burns account for 2-3% of pediatric burns assessed in the emergency department
Low-voltage injuries account for 60-70% of electrical injuries, usually < 6 yrs with oral or hand contact on electrical cord or sockets
High-voltage injuries: children > 12 yrs with risk-taking behavior
Factors Determining Severity of Electrical Injuries
Resistance of tissue:
Mucous membranes, nerve tissue, and moist skin have very low resistance
Type of current:
Low voltage (< 600 volts)
Alternating current (AC) causes tetanic contraction and “locking on” extending duration of contact
Direct current (DC) will cause single contraction that may throw the victim
High voltage (600-1,000,000 volts): causes single contraction in AC and DC
Current intensity:
• | 3-5 mA: | maximum current at which a child can “let go” |
• | 20-50 mA: | paralysis of respiratory muscles |
• | 50-100 mA: | ventricular fibrillation |
• | > 2 A: | asystole |
Pathway taken by the current:
Vertical pathway: parallel to axis of body, involves all vital organs, 20% mortality from cardiac arrhythmias
“Hand to hand”: involves heart, respiratory system, spinal cord C4-C8 (most dangerous, 60% mortality)
“Leg to leg”: usually not lethal (< 5% mortality)
Clinical Manifestations
Cardiovascular
Dysrhythmias
Asystole: high voltage and lightning; sinus rhythm may spontaneously return due to automaticity of the heart
Ventricular fibrillation: low voltage
Other: sinus tachycardia, atrial fibrillation, SVT
Conduction defects: AV block, bundle branch block
Myocardial necrosis may occur when the current passes through the heart
Cardiac ischemia secondary to anoxia
Note: Degree of injury to heart depends on voltage; at any given voltage, AC is worse than DC
