Glossary

Active Electrode: An electrosurgical instrument or accessory that concentrates the electric (therapeutic) current at the surgical site.
Alternating Current: A flow of electrons that reverses direction at regular intervals.
Bipolar Electrosurgery: Electrosurgery where current flows between two bipolar electrodes that are positioned around tissue to create a surgical effect (usually desiccation). Current passes from one electrode, through the desired tissue, to another electrode, thus completing the circuit without entering any other part of the patient’s body.
Cautery: The use of heat or caustic substances to destroy tissue or coagulate blood.
Circuit: The path along which electricity flows.
Coagulation (Coag): The clotting of blood or destruction of tissue with no cutting effect; electrosurgical fulguration and desiccation.
Contact Quality Monitoring: A system that actively monitors tissue impedance (resistance) at the interface between the patient’s body and the patient return electrode and interrupts the power if the contact quality and/or quantity is compromised.
Current: The number of electrons moving past a given point per second, measured in amperes.
Cut: A low-voltage, continuous waveform optimized for electrosurgical cutting.
Cutting: Use of the cut waveform to achieve an electrosurgical effect that results from high current density in the tissue causing cellular fluid to burst into steam and disrupt the structure. Voltage is low and current flow is high.
Direct Coupling: The condition that occurs when one electrical conductor (the active electrode) comes into direct contact with another secondary conductor (scopes, graspers). Electrical current will flow from the first conductor into the secondary one and energize it.
Electrosurgery: The passage of high-frequency electrical current through tissue to create a desired clinical effect.
Electrosurgical Smoke/Plume: Byproducts of combustion and/or vaporization of human tissue created by heating with high (radio) frequency electrical current. The smoke/plume contains gases that may be flammable.
Eschar: A scab or dry crust that results from trauma, such as a chemical or electrical burn, infection, or excoriating skin disease. Blackened/carbonized tissue created by electrosurgical or laser energy.
ESU: ElectroSurgical Unit.
Fire Triangle: Three (3) elements, ignition (heat) source, fuel source, and oxidizer, that may result in a fire if combined in the right proportions.
Flammability Characteristics: Properties of an item that is capable of burning, including but not limited to, resistance to combustion, temperature at which combustion will occur, flame spread speed, and flame spread pattern.
Frequency: The rate at which a cycle repeats itself; in electrosurgery, the number of cycles per second that current alternates.
Fuel Source: Any item or product in or on the patient that has the property of igniting and burning easily and rapidly (flammable).
Fulguration: Using electrical arcs (sparks) to coagulate tissue. The sparks jump from the electrode across an air gap to the tissue.
Generator: The machine that converts low-frequency alternating current to high-frequency electrosurgical current.
Ground, Earth Ground: The universal conductor and common return point for electric circuits.
Heat Source: See Ignition Source.
Hertz: The unit of measurement for frequency, equal to one cycle per second.
Ignition Source: A device or item that is capable of generating sparks or enough heat to produce combustion.
Impedance: A form of electrical resistance observed in an alternating current that is analogous to the classic electrical resistance that occurs in a direct current.
Insulation Failure: The condition that occurs when the insulation barrier around an electrical conductor is breached. As a result, current will travel outside the intended circuit.
Intestinal Gases: Gases produced by bacteria in the gastrointestinal tract that contain approximately 44% hydrogen and 30% methane, both of which are flammable. A normal colon contains at least 5% oxygen, but these concentrations increase with the administration of general anesthesia using oxygen or nitrous oxide.
Isolated Output: The output of an electrosurgical generator that is not referenced to earth ground.
Laser: Acronym for light amplification by stimulated emission of radiation; a source of intense monochromatic radiation of the visible, ultraviolet, or infrared portions of the spectrum. Lasers are used in surgery to divide or cause adhesions, or to destroy or fix tissue in place.
Leakage Current: Current that flows along an undesired path, usually to ground; in isolated electrosurgery, RF current that regains its ground reference.
Monopolar Electrosurgery: A surgical procedure in which only the active electrode is in the surgical wound; electrosurgery that directs current through the patient’s body and requires the use of a patient return electrode.
Ohm: The unit of measurement of electrical resistance.
Oxidizer: A compound or element that contains oxygen or is capable of giving up oxygen when heated; gases that increase oxygen concentration and support combustion.
Oxygen enriched atmosphere (environment): Atmosphere (air) with greater than 21% concentration of oxygen. An oxygen enriched atmosphere is favorable to fire and explosion.
Patient Return Electrode (PRE): A conductive plate or pad (dispersive electrode) that recovers the therapeutic current from the patient during electrosurgery, disperses it over a wide surface area, and returns it to the electrosurgical generator.
Power: The amount of heat energy produced per second, measured in watts.
Radiofrequency (RF): An electrical current that alternates the poles in the radiofrequency range (300 kHz–36 Hz); the high-frequency current used in electrosurgery.
Resistance: The lack of conductivity or the opposition to the flow of electric current, measured in ohms.
Return Electrode Contact Quality Monitoring System (RECQMS): A generic term for an electrosurgical generator technology that monitors the quality of the pad/patient interface by measuring the resistance under the patient return electrode and allows the generator to operate only within the preset safe parameters.
Volt: The unit of measurement for voltage.
Voltage: The force that pushes electric current through impedance/resistance; electromotive force or potential difference expressed in volts.
Watt: The unit of measurement for power.