Electrical injuries are divided into high-voltage injuries (≥1000 V), low-voltage injuries (<1000 V), and electric arc flash burns, which by definition do not result in passage of current through the tissues. Lightning injury is an extreme and unique form of electrical injury. This chapter also discusses injuries caused by electronic control devices, such as the Taser®. Burns from electrical accidents can result from heating due to electric current flow through tissues, explosions, and burning of flammable liquids, clothes, and other objects. Burns are discussed in Chapter 217, “Thermal Burns.”
Approximately 6500 electrical injuries occur per year in the United States, accounting for 4% of total burns. Of these, the majority are work related (61%), mostly industrial injuries. The overall complication rate is 10.6%, with the fewest complications among children aged 1 to 5 years (2%).1 There were 134 fatal electrical injuries reported by the Electrical Safety Foundation International in 2017, a slight decline from previous years.2,3 The most common high-voltage injuries in the United States are also work related and include arc burns in electricians and high-voltage injuries in power line workers.4 High-voltage power line injuries are particularly disabling because they often lead to deep muscle necrosis and the need for fasciotomy and amputation.4
Electric current is the movement of electrical charges. Table 219-1 lists a few key terms related to electricity.
TABLE 219-1Electrical Terms and Units of Measure |Favorite Table|Download (.pdf) TABLE 219-1 Electrical Terms and Units of Measure
|Term ||Unit of Measure |
Movement of electrical charges
Driven by voltage or electrical potential difference
Hindrance to flow of current
Ohm’s law (current = voltage/resistance)
The current is proportional to voltage.
The current is inversely proportional to resistance.
Current flow is measured in amperes. Current flow is driven by an electrical potential difference, which is measured in volts. Intervening material between two or more contact points resists electric current flow; this resistance is measured in ohms. Ohm’s law describes the relationship between current (I), voltage (V), and resistance (R) and states that the current through a conductor between two points is directly proportional to the potential difference or voltage drop across the two points and inversely proportional to the resistance between them. For example, a person who grasps a grounded pipe in one hand and a metal cable connected to a 120-volt source in the other hand will experience a current flow through the body, the magnitude of which varies inversely with the resistance of the circuit. If the total resistance from the power source, through the person, and to the ground is estimated to be 1000 Ω, the current (I) would be calculated as follows: I = (120 V)/(1000 Ω) = 0.120 A = 120 mA.
Conductors are materials that allow electric current to flow easily. Insulators are materials that do not allow electric current flow. Tissues with high fluid and electrolyte content conduct electricity better than tissues ...