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Electrical burns
Electrical burns
Electrical burns occur when high current density flows through a small surface area. This usually happens when there is faulty application of the indifferent electrode, the patient makes contact with a metal surface, or there is current channeling to a distant site.
Improper placement of the indifferent electrode includes placing it over a bony prominence, scar tissue, or metal implants, or when too small of a surface area of the indifferent electrode is in contact with the patient. Current becomes concentrated in this small surface area, resulting in high current density. If this high current density is allowed to continue for too long, then an electrical burn occurs. A patient would normally experience pain and discomfort prior to experiencing a focal burn, but if the area is anesthetized they may not.6,23โ25
A patient is also at risk for burns if he or she makes contact with a grounded metal object while electrocautery is occurring. This is especially true when the indifferent electrode is broken or improperly placed, or when using a monoterminal unit. This is because current seeks any alternative low-resistance pathway from the patient to the ground.
Another cause of burns is a phenomenon known as current channeling. This is when current is concentrated as it flows through a small area. For instance, if applying current to a mass with a narrow base or stalk, such as a fibroepithelial polyp, as the current flows into the narrow stalk it is concentrated. This concentrated current can cause a burn at the site of the base of the lesion.26,27
The threat of burns can be mitigated through a few simple precautions. Never leave an active electrode on a patient when not in use. A patient should always be in contact with at least 20 square inches of the indifferent electrode to ensure sufficient current dispersion. This is made easier by flexible indifferent electrodes that conform to the body, the use of protective interface gels, and contact quality monitors. Many modern electrosurgery units have a contact quality monitor for the dispersive electrode. It measures the quality of contact between the patientโs skin and the dispersive electrode
as well as between the electrode and the generator. However, there is no clinical evidence to support the notion that a contact quality monitor minimizes the risk of burns.10
Never use a bent indifferent electrode, as this can create a sharp point that concentrates current. Make sure the patient is not in contact with any metal surfaces. If the patient has any metal in his body, the dispersive pad should be placed between the metal and the surgical site to prevent current from passing through the patientโs implanted device. When treating a pedunculated lesion for which there is risk of channeling, use bipolar forceps or wrap a saline-soaked sponge (an electrolyte conductor) around the stalk.26โ28