Makindo Medical Notes

Alternating Current (AC), such as that used in mains electricity, is 3–5 times more dangerous than the equivalent Direct Current (DC), which is typically found in batteries. This is due to the alternating nature of AC, which can lead to more severe physiological disruptions.

About

• Electrical injuries occur due to exposure to either Alternating Current (AC) or Direct Current (DC).
• AC is generally more dangerous than DC because it causes muscles to contract in a tetanic fashion, increasing the risk of prolonged exposure.

Aetiology

• Electrical injury can be caused by either AC (where current flow reverses direction) or DC (where current flows in a single direction).

Factors Influencing Damage

• Type of current: AC is 3–5 times more dangerous than an equivalent voltage of DC.
• Voltage and current: Higher voltage and amperage (current) result in more severe injuries.
• Duration of exposure: The longer the exposure to electrical current, the greater the damage.
• Body resistance: Human skin provides resistance, which varies based on moisture, but internal tissues conduct electricity easily once the skin is breached.
• Pathway of current: Injuries are more severe when the current passes through vital organs such as the heart, often occurring when the current travels from hand to foot.
• Heat generation: The extent of thermal damage is calculated as I (current) x I (current) x R (resistance) x T (time). The heat can cause deep burns and tissue necrosis.

Clinical Features

• Cardiac arrhythmias: Can range from minor irregularities to fatal arrhythmias such as ventricular fibrillation.
• Cardiac arrest and death: Electrical currents passing through the heart can stop its function.
• Neurological damage: Coma, paralysis, and other neurological injuries may occur due to brain or spinal cord damage.
• Burns: Electrical injuries often cause burns that affect both the skin and deeper tissues, including muscles.
• Muscle damage and necrosis: Rhabdomyolysis (muscle breakdown) can result from the heat generated by electrical currents.
• Ocular and auditory damage: Cataracts and ruptured tympanic membranes are common after high-voltage injuries.

Investigations

• Blood tests: Full Blood Count (FBC), Urea & Electrolytes (U&E), Arterial Blood Gases (ABG), Creatine Kinase (CK), Troponin to assess for rhabdomyolysis and myocardial damage.
• ECG: To assess for arrhythmias or myocardial ischaemia.
• Continuous monitoring: Continuous ECG and telemetry monitoring are recommended in moderate to severe electrical injuries.

Management

• Airway, Breathing, Circulation (ABC): Immediate attention to ABC is critical. Bystander Cardiopulmonary Resuscitation (CPR) may save lives before medical assistance arrives.
• Cardiac monitoring: Patients should be continuously monitored in a Coronary Care Unit (CCU) or Intensive Care Unit (ICU) setting to detect arrhythmias.
• Intravenous fluids: Administer IV fluids to maintain blood pressure and urine output, and to prevent renal damage from myoglobin released by muscle breakdown (rhabdomyolysis). Caution must be exercised to avoid exacerbating cerebral oedema.
• Surgical intervention: Surgical debridement may be necessary for areas of deep tissue necrosis to prevent infection and promote healing.
• Electrolyte monitoring: Electrolytes should be closely monitored to detect imbalances, such as hyperkalemia, which may arise from muscle breakdown.