The risk of electrical injuries is often over-looked to over familiarity. In most cases, accidents occurring from faulty domestic electrical apparatus, rarely it may be from high tension lines of other installations. Electrical characteristics of the exposed part, conductivity of the tissues, amount of grounding and the duration of contact determine the amount and the path taken by the current which is important in relation to the severity of injury. Electrical accidents are common where electrical installations are more, eg, surgical theaters, intensive care rooms etc.
The type and severity of injury depends upon the strength of the current, its type and duration of exposure. Individuals vary in susceptibility to the effects of electricity. Injuries associated with electricity may be due to either direct electrical shock, or burns resulting from electro-thermal shock, or burns resulting from electro-thermal effects and flames. Alternating current (AC) is more damaging than direct current DC. A current of 100 mA flowing from hand to feet can inductive ventricular fibrillation. Following the passage of the current, the myocardium is vulnerable and highly excitable. Fatal ventricular arrythmias may occur. Burns develops at the sites of entry and exit of the current. When the current is high, instantaneous ignition of clothing or nearby objects add to the injury. The burns get secondarily infected in 2-3 days.
The nervous system is highly sensitive to electrical injury. Spinal cord may develop lesions leading to paraplegia and urinary retention. Convulsions, cerebral edema, and cerebral thrombosis may develop. Cardiac symptoms include tachycardia, which may be persistent, shock, cardiac arrhythmias, and cardiac failure. Pneumonia, pleural effusion, disorders of ventilation, and hypoxia are the common respiratory lesions. Secondary hemorrhage from blood vessels and acute upper gastrointestinal bleeding may develop in a few days. Acute renal failure is a common sequel. Current passing through the abdomen may be complicated by damage to the viscera. Cataracts may form as late sequelae.
Treatment : First aid includes immediate disconnection of the live contact and cardiorespiratory resuscitation. Due to muscle spasm, the limit holds on to the live wire. This prolongs the injury and this is the main cause of death.
Administration of intravenous saline or Ringer lactate solution helps to combat shock. Dexamethasone 8 mg given intravenously and 20% mannitol 250 ml given intravenously help to reduce cerebral edema. Furosemide 40-80 mg intravenously is given to overcome pulmonary edema and prevent renal shut down. Sodium bicarbonate is given to prevent acidosis as an early measure. The progress is monitored by estimating the hematocrit, urine volume and arterial pH serially. Suspicion of visceral damage calls for surgical management.
Prevention : Proper insulation is necessary while handling electrical equipment. Low plug sockets should be protected from the reach of children. While rescuing an electrocuted person, the rescuer should take enough care in first insulating himself properly. Many deaths have occurred among rescuers who have failed to observe proper precautions.
Lightning
Injuries due to lightening are encountered in the tropics. Lightening induces a high electrostatic charge on the victim. Identically charged particles repel each other, giving rise to disruptive forces which lead to damage of organs. Organ damage may occur even without external injury. The high current produces violent muscular contractions and severe burns and ignite inflammable objects on the body. The patient is usually restless, disoriented and may be comatose. Retrograde amnesia is common. Later on he may show psychiatrist and hysterical manifestations. Severe vasoconstriction produces manifestations like cold limbs and transient ischemic palsies. Arterial spasm may result in loss of pulse in the affected limb. Increased vascular permeability results in massive edema of the affected part. Cardiovascular manifestations including tachycardia, extrasystoles and electrocardiographic abnormalities such as elevation of ST segment and depression of T waves. Sudden death may occur on account of respiratory center paralysis, ventricular fibrillation, or Cardiac arrest.
Treatment : If the vital signs are absent, immediate resuscitatory measures should be started. Even in apparently hopeless cases, gratifying results are not uncommon. Management of survivors consists mainly of supportive measures and treatment of the complications. Vasodilators and low molecular weight dextran help to prevent gangrene. Tetanus prophylaxis must be given if tissue injury has occurred.