Electrosurgery in the gastroenterology suite: principles, practice, and safety.

An electrosurgery generator is a critical piece of equipment in any therapeutic endoscopy setting. Electrosurgery uses rapidly alternating current, provided by the electrosurgery generator, for both therapeutic cutting and coagulation of tissue. Basic variables important to electricity in general are also important to electrosurgery: current, voltage, circuit, and impedance (resistance). Monopolar and bipolar accessories (electrodes) are used in the endoscopy suite and these terms refer to the way in which the electric circuit is completed by the flowing current. Impedance resists current flow and changes with tissue type and degree of therapeutic coagulation. Waveforms are the high-frequency output selected by the operator when using an electrosurgery generator. Waveforms may be continuous or interrupted (modulated) and differ in voltage and degree of modulation. Certain waveforms are typically chosen for particular applications or accessories, such as polypectomy with a snare, because of predictable tissue-effect attributes of that waveform. Safe application of grounding pads, careful management of active accessories, and good care of electrosurgical equipment are crucial to patient and operator safety.