It is estimated that a lightning flash occurs approximately 8 million times per day throughout the world. Most strikes are benign and cause little damage to property and physical structures; however, when lightning strikes a person or group of people, it is a significant medical and potentially traumatic event that could lead to immediate death or permanent disability. By understanding some basic physics of lightning and pathophysiology of injuries associated with lightning strikes, EMS providers will be better prepared to identify assessment findings, anticipate complications and provide effective emergency care.
Lightning strikes are one of the top three causes of death associated with a natural or environmental phenomenon and are the second leading cause of storm-related deaths in the United States. According to the National Oceanic and Atmospheric Administration's (NOAA) National Weather Service publication, Storm Data, there are on average 62 reported deaths per year due to lightning strikes in the U.S. Since there is no standardized reporting system and most of the data is collected from newspaper accounts of lightning-strike injuries and deaths, the average is thought to be low. The National Weather Services estimates it is closer to 70. Of those people struck, it is believed that only 10% are killed; the remaining 90% suffer some type of acute or permanent disability.
Most lightning-strike injuries occur between May and September, with the highest incidences in June, July and August. Approximately one-third of strike injuries are work related, one-third occur during recreational or sports activities, and one-third as a result of other situations, such as being struck while indoors or on the telephone.
Although one of the safest places to be during lightning is indoors in a substantial improved structure with electrical wiring and plumbing, do not assume that all lightning-strike patients will be found outdoors. If lightning strikes the structure or a nearby object, the electrical energy can be transmitted through plumbing fixtures like a sink, shower or toilet, and electrical devices that are hard-wired to the structure, such as computers, phones and electronic games. The incidence of lightning -strike injuries increased among emergency services call-takers and dispatchers when they began using headsets that were hard-wired into radio consoles. A person talking on a landline telephone is also at risk of being struck, as the electrical energy is transmitted through the phone line and receiver being held to the ear. Although phone lines are grounded, the extremely high electrical energy associated with a lightning strike overwhelms the ground, which provides little or no protection. Acoustic injury from the loud crack of static electricity has been reported in people using a portable phone with a hard-wired base during lightning. Cell phones pose no increased risk, other than promoting inattention to the weather and surroundings.
It is often thought that a shelter will provide adequate protection against a lightning strike. Unfortunately, this is not true. A shelter may protect against rain and wind, but seeking protection in one may actually increase the risk of being struck by indirectly increasing the height surrounding the individual.
Cars, buses and other vehicles surrounded by metal provide a safe shelter against lightning. A common misconception is that the rubber tires of a vehicle provide the protection; however, the power of a lightning strike easily overwhelms the little protection offered by the tires. It is the metal structure that allows the energy to be dispersed along the outside of the vehicle and keep the occupants inside safe from injury, providing they are not in contact with electrical devices like the radio or the metal of the car itself.