Ch 2 - Injury Prevention - Concepts of Injury

Concepts of Injury

Definition of Injury A discussion of injury prevention should begin with a definition of the term injury. The wide variability of the causes of injury initially represented a major hurdle in its study and prevention. For example, what does a fractured hip caused by an elderly person’s fall have in common with a self-inflicted gunshot wound to the head of a young adult? All possible causes of injury— from vehicle crash, to stabbing, to suicide, to drowning— have one factor in common: energy transfer. Injury is now commonly defined as a harmful event that arises from the release of specific forms of physical energy or barriers to normal flow of energy. 11 Typically, energy exists in five physical forms: mechanical, chemical, thermal, radiation, or electrical.

Mechanical energy is the energy that an object contains when it is in motion. For example, mechanical energy, the most common cause of injury, is transferred from a vehicle when an unrestrained driver collides with the windshield during a vehicle crash.

Chemical energy is the energy that results from the interaction of a chemical with exposed human tissue. For instance, chemical energy occurs when a curious child drinks ammonia found in an unlocked cabinet in the kitchen.

Thermal energy is the energy associated with increased temperature and heat. For example, thermal energy causes injury when a cook sprays lighter fluid on actively burning charcoal in an outdoor grill, which then flashes in his face.

Radiation energy is any electromagnetic wave that travels in rays (such as x-rays) and has no physical mass to it. Radiation energy produces sunburn to the teenager searching for a golden tan for the summer.

Electrical energy results from the movement of electrons between two points. It is associated with direct injury as well as thermal injury and, for example, damages the skin, nerves, and blood vessels of a prehospital care provider who fails to do a proper scene assessment before touching a vehicle that hit a power pole.

The body requires basic elements, such as oxygen and heat, to produce the internal energy needed to function properly. If conditions arise that prevent the body from using these necessary elements, injury can result. Suffocation and hypothermia are physical injuries that result from an interruption of the body’s normal energy flow. Any form of physical energy in sufficient quantity can cause tissue damage. The body can tolerate energy transfer within certain limits; however, an injury results if this threshold is breached. A bullet fired from a pistol at point-blank range easily passes through skin and soft tissue, causing massive injury . If the intended victim is far enough away, theoretically, the potential victim can simply stick out a hand, and the bullet would hit his palm and fall harmlessly to the ground . As the energy dissipates in the air on its flight, the bullet does not have enough energy on impact to exceed the body’s tolerance level. Such a situation rarely happens.

Energy Out of Control

People harness and use all five forms of energy in many productive