Lecture 5

Electrical injury is a physiological reaction caused by electric current passing through the body.

The injury depends on

• the density of the current,
• tissue resistance and
• duration of contact.

Very small currents may be imperceptible or produce a light tingling sensation. A shock caused by low and otherwise harmless current could startle an individual and cause injury due to jerking away or falling.

Stronger currents may cause some degree of discomfort or pain, while more intense currents may induce involuntary muscle contractions, preventing the person from breaking free of the source of electricity. Still larger currents result in tissue damage and may trigger ventricular fibrillation or cardiac arrest.

Electric injury occurs upon contact of a body part with electricity that causes a sufficient current to pass through the person's tissue. Contact with energized wiring or devices is the most common cause. In cases of exposure to high voltages, such as on a power transmission tower, direct contact may not be necessary as the voltage may "jump" the air gap to the electrical device.

Following an electrical injury from household current, if a person has no symptoms, no underlying heart problems, and is not pregnant further testing is not required. Otherwise an electrocardiogram, blood work to check the heart, and urine testing for signs of muscle breakdown may be performed