A Review of Capacitive Return Electrodes in Electrosurgery

Abstract

Background: Monopolar electrosurgery, one of the most widely used techniques in surgery, requires two electrodes: a working electrode and a return electrode. Commonly, adhesive or "sticky" pads that attach directly to the patient are used as return electrodes. Acting as electrolytic conductors, adhesive pads are highly effective, but require some effort to apply and remove, and if improperly placed or partially detached may lead to high electrical current density and the potential for pad site burns. Alternatively, a capacitive return electrode, such as the Mega Soft pad, may be used that works on the same principle as a two-plate capacitor. Objective: This article details the technology underlying capacitive electrodes, reviews the scientific literature to-date, and provides recommendations on how to best use the Mega Soft pad. Results: No direct contact is required between the pad and patient, and the return electrode is designed so that current density is limited regardless of pad placement, reducing the risk of pad site burn. Although the technology is now mature, having been in the field for over 20 years, best practices for optimal performance from capacitive return electrodes are still not widespread, and misunderstandings persist regarding use of capacitive electrodes with contact monitoring systems and implantable electronic devices. Conclusion: With proper training, capacitive return electrodes may be substituted for conventional adhesive pads with the benefits of easier application and reduced risk of pad site burns.

Heart Rhythm New Zealand consensus statement on the practical management of cardiac implanted electronic devices in the peri-operative environment

“…2 Newer capacitive return electrodes (mattress type) may disperse the current throughout the body depending on mattress placement regardless of the anatomical site of surgery, so devices are at higher risk of EMI, especially if the mattress is under the patient's chest. 6,7 PPM implanted in the abdomen will be more exposed to EMI during abdominal or pelvic surgery. Monopolar electrosurgery above the iliac crest and/or <15cm from the device has a higher risk of EMI.…”

“…Asynchronous pacing will only occur while the magnet is in situ. [1][2][3]6 Please note the magnet response for Biotronik devices is only asynchronous for 10 beats unless the magnet response is specifically programmed to "async". [1][2][3][4] For ICD patients there is the potential for inappropriate ICD shock therapy during electrosurgery due to sensing of EMI (Table 1).…”

“…• Patients with CIEDs who underwent monopolar electrosurgery with a capacitive return mattress and there is a greater probability of EMI affecting device function, as determined by a specialist device physiologist 2,6. • Patients with CIEDs who underwent monopolar electrosurgery above the iliac crest and there is a greater probability of…”