From the Guidelines
Capacitive coupling causes thermal injury when electrical current from an active electrode transfers to nearby conductive materials through an insulating barrier, creating an unintended electrical circuit that generates heat. This occurs during electrosurgery when the active electrode's insulation is intact but in close proximity to metal instruments or tissue, as supported by the principles outlined in 1. The electrical energy creates a capacitor effect, allowing alternating current to flow through the insulation and into adjacent conductive materials. As this current seeks a path to ground, it concentrates at points of tissue contact, causing localized heating and potential burns at sites distant from the surgical field. These injuries typically occur outside the surgeon's field of vision, making them particularly dangerous. Key factors that increase the risk include higher voltage settings, longer activation times, and when the active electrode remains in one position for extended periods, as would be inferred from the general principles of electrical injury discussed in 1 and the management of thermal burns in 1. To prevent capacitive coupling injuries, surgeons should use lower power settings when possible, minimize activation time, avoid contact between the active electrode and other metal instruments, and employ active electrode monitoring systems that can detect insulation failures. The most relevant choice related to the cause of thermal injury due to capacitive coupling is A, as it involves the transfer of electric current to organs or tissues touched by a metal object, which can act as a conductor. However, the precise mechanism involves the generation of heat due to the flow of electrical current through the body, which aligns with the principles of electrical injury discussed in 1. Therefore, the correct understanding of capacitive coupling causing thermal injury is closely related to the concept described in option A, but with a clearer emphasis on the electrical current's role in generating heat as it passes through the body, as explained by the effects of electric shock in 1.
From the Research
Capacitive Coupling and Thermal Injury
- Capacitive coupling can cause thermal injury through the transfer of electrical energy to non-targeted tissues, resulting in burns and tissue damage 2, 3, 4, 5.
- This can occur even with intact instrument insulation, particularly when an open circuit is formed, allowing stray currents to flow into neighboring tissues 2, 3.
- The risk of capacitive coupling is increased when there is increased contact with the cystic wall, especially with cysts less than 3 cm in diameter 2.
- Capacitive coupling can lead to electrical skin burn injury during laparoscopic surgery, resulting in collagen hyalinization, nuclear fragmentation, and coagulation necrosis 3.
- Preventive measures, such as thorough staff training, regular safety inspections, and strict procedure performance, can minimize the risk of capacitive coupling and related thermal injuries 2, 6, 4, 5.
Mechanisms of Injury
- Capacitive coupling is one of several mechanisms that can cause electrical injuries during laparoscopy, including direct contact, electric arc, insulation failure, and direct or capacitive coupling 4.
- Insulation failures, direct coupling, and capacitive coupling around active electrodes can cause serious burns and tissue damage to patients undergoing laparoscopic procedures 5.
- The use of electrosurgical devices can increase the risk of thermal injury, and perioperative nurses should standardize processes and participate in education activities on electrosurgical safety to help prevent injuries 6.
Prevention and Safety
- Appropriate measures, such as careful manipulation of electrosurgical instruments and avoidance of open circuits, can minimize the risk of capacitive coupling and related thermal injuries 3.
- A coordinated team effort between perioperative nurses and surgeons can prevent life-threatening complications from laparoscopic electrosurgical procedures 5.
- Knowledge of the biophysics of electrosurgery, the mechanisms of electrosurgery complications, and prevention of patient injuries is essential for providing quality outcomes for patients undergoing laparoscopic procedures 5.