Electrical injury results from the passage of an electric current through the body. Its severity is influenced by various factors such as the current’s density, the body tissue resistance and the duration of contact. Although small currents may not be noticeable or may only cause a slight tingling sensation, low but otherwise harmless currents can still startle a person, leading to injury due to sudden movements or falls. Electric currents of greater intensity may elicit discomfort or pain and, in some cases, involuntary muscle contractions that hinder an individual from breaking free from the electrical source. As the current becomes stronger, it can lead to tissue damage, ventricular fibrillation, or cardiac arrest. The effects of the electrical injury may extend to amputations, bone fractures, and orthopaedic and musculoskeletal injuries. When an electric shock leads to death, it is commonly referred to as electrocution.
Four types of electrical injuries exist, namely, flame, flash, true and lightning injuries. Arc flashes are associated with flash injuries, which primarily cause superficial burns, as the electrical current does not penetrate the skin. Flame injuries happen when an arc flash burns a person’s clothing; in such cases, the electrical current may or may not pass through the skin. Before using electric devices, be sure to check their electrical symbols to know about the electrical elements inside the devices. This will help to be aware of the probable hazards connected to the various electrical elements inbuilt into the devices.
Lightning injuries, which entail brief but exceptionally high-voltage electrical energy, involve the passage of an electrical current through an individual’s entire body. True electrical injuries arise when a person becomes part of an electrical circuit, and such cases typically exhibit entrance and exit points. Now let’s go through 5 important facts about electrical shock.
Shock Body Resistance
The voltage required to cause electrocution is determined by both the current flowing through the body and the duration of that current. Ohm’s law indicates that the current that passes through the body depends on the body’s resistance. The resistance of human skin is not consistent and varies from person to person, as well as at different times of the day. Most international safety and health organisations have established that the resistance of a dry human body can reach up to 105 ohms, while wet skin can decrease the resistance to 103 ohms. When high-voltage electrical energy comes into contact with human skin, it can rapidly deteriorate the skin, reducing the body’s resistance to as low as 5 × 102 ohms.
Electric Shock Can Change the Neural Structure of the Brain
Despite being the most powerful and influential organ in our bodies, the brain is also one of the most vulnerable. It is encased in a hard bony structure to protect it from harm. As we are aware of the impact of drugs on our brains, it should come as no surprise that exposure to certain levels of electrical shock can also have detrimental effects on the brain. In fact, even brief exposure to a certain level of electricity can destroy the fundamental neural structure of the brain in a matter of microseconds, similar to how drugs can alter our brain chemistry. Lightning strikes, being the oldest type of electrical shock, are also among the most harmful forms of electric shock for the brain.
One of the most challenging aspects for survivors to cope with is the changes in the victims’ character. After experiencing electrocution, changes in mood, mood swings and memory loss are common occurrences. These issues arise due to the changes in the neural networks of the brain. Certain areas of the brain can sustain severe damage while other regions are altered. Thankfully, these symptoms usually disappear within a few weeks or months. However, in rare cases, they can have long-term consequences on the individual’s life.
Macroshock and Microshock
Macroshock is a type of electric shock that can pass through the body via intact skin, creating a current that can potentially travel through the heart. When the current flows from arm to arm or between an arm and a foot, it poses a greater risk compared to when it flows between a leg and the ground. It is important to note that this type of shock can only enter the body through the skin.
Microshock refers to the transmission of a low-level current that has a direct pathway to the heart tissue. The shock is typically delivered from an internal source, such as a pacemaker lead, a guide wire, or a conductive catheter. It must be administered directly to the heart through the skin. Although this type of shock is considered a theoretical hazard, modern devices used in these situations are equipped with safeguards to prevent such currents from causing harm.
Water Is Not a Good Conductor of Electricity
There is a common understanding that water is a highly effective conductor of electric shock for humans and other organisms with some degree of dampness or moisture in their bodies. However, the widely held belief that water is a good conductor of electricity lacks a scientific basis. In reality, water is chemically proven to be one of the least efficient conductors of electricity.
Due to its lack of unstable electrons, water has a very limited ability to create a flow between its molecules. However, there is a unique aspect to the behaviour of water in the real world: electricity can move through water with ease. This phenomenon is attributed to the presence of dissolved solids, such as minerals and metals, in the water. Therefore, the next time you witness someone getting electrocuted by standing in a puddle, you can discuss with your friends how the individual would have been better off if the puddle were made of ultra-pure, filtered and distilled water.
Lethality Factors of Electric Shock
The fatality of an electric shock is determined by several factors. The greater the current, the more probable it is to be fatal. Since the ampere value (current) is proportional to voltage when resistance is fixed, high voltage is an indirect risk for producing higher currents. The duration of the electric shock also plays a significant role in its lethality. Safety switches can limit the duration of the current flow. If the current flow through the heart muscle, it is more likely to be lethal. High voltage can cause dielectric breakdown at the skin, reducing skin resistance and allowing for a further increase in current flow. Small currents can affect artificial cardiac pacemakers or implantable cardioverter-defibrillators. Additionally, pre-existing medical conditions can significantly amplify the effects of an electric shock.
Practicals Applications of Electric Shock
Electric shock is sometimes utilised as a medical treatment in carefully regulated circumstances. Examples of such use include
- Electroconvulsive therapy is a psychiatric treatment for mental disorders.
- Electrosurgery employs high frequencies and currents with different amplitude modulation techniques to cut or coagulate tissues. It is used as a treatment for irregular heart rhythms, fibrillation, pain relief and excessive sweating via iontophoresis.
- Electrodiagnosis involves nerve conduction studies and electromyography.
- Electroporation is a method for gene delivery.