Alternate site burns can occur via current division or diversion through processes such as capacitive coupling, direct coupling, and insulation defects. Capacitive coupling is the phenomenon by which current appears to leak across insulation to a second electrically conductive structure, potentially causing inadvertent thermal injury away from the target site. These electrical discharges are uncommon with current endoscopic technology. Direct connection between the active electrode and another electrically conductive accessory can lead to serious alternate site burns, such as thermal injury to the biliary tree as a result of current conduction between a sphincterotome wire and a frayed guidewire. Endoscopic insulation failure occurs when the instrument’s shaft is compromised due to wear and tear or poor handling. Small cracks are more hazardous than easily detectable ones because they concentrate current and are more likely to cause injury. Thus, careful inspection of all accessories prior to use is mandatory.
7.5.2 Implanted Electromagnetic Devices
The electrical current produced by ESUs can interfere with implanted electromagnetic devices, including permanent pacemakers (PPMs), implantable cardioverter-defibrillators (ICDs), and medication pumps, resulting in undesirable effects, such as device reprogramming, pacemaker inhibition, and ICD-induced shocks.
For PPMs, no reprogramming is needed if the patient is not dependent on the pacemaker. If the patient is pacemaker-dependent and prolonged use of electrosurgery is anticipated, the PPM should be synchronized to the asynchronous mode (VOO or DOO). For a patient with an ICD, a cardiology team or a team dedicated in the management of implantable cardiac devices should be consulted. The ICD should be reprogrammed to inactivate tachyarrhythmia detection before the use of electrosurgery. Alternatively, a magnet can be used if it can be secured over the pulse generator of the ICD. Continuous cardiopulmonary monitoring during the procedure is mandatory, with cardioversion–defibrillation equipment on standby. When feasible, the bipolar mode should be used over monopolar applications. If a monopolar output is required, the dispersive electrode (pad) should be placed away from the leads of the implanted device, with judicious use of current application. Postprocedure, the PPM or ICD should be reprogrammed to restore baseline function of the device.22,23
7.5.3 Bowel Explosion
Explosion has occurred in poorly prepped or unprepped colons exposed to electrosurgery. Polyethylene glycol or sodium phosphate cleansing preparations render the bowel safe for electrosurgery by decreasing the concentrations of combustible gases, mainly hydrogen, methane, and oxygen. The use of carbon dioxide for insufflation may also reduce the risk of explosion. Mannitol- or sorbitol-based preparations are contraindicated due to hydrogen gas production from these sugars by colonic bacterial fermentation. Enema preparations are insufficient for the safe performance of electrosurgery during flexible sigmoidoscopy, and explosion has been documented during unprepped proctoileoscopy and APC in a patient with subtotal colectomy.24
7.6 Conclusion
ESUs and electrosurgical devices are widely utilized during therapeutic endoscopy, yet remain a poorly understood technology among users, regardless of years of experience.25 A key understanding of the fundamental properties of electrosurgery aids in the educated selection of ESU settings and devices for a particular indication and desired tissue effect, and enhances the safety and performance of commonly performed procedures, such as snare polypectomy, hot biopsy, sphincterotomy, hemostasis, and APC.
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