From the Guidelines
Capacitive coupling causes thermal injury by transferring electrical energy through insulating materials, leading to unintended tissue heating. This occurs when an electrical current from an active electrode creates an electrical field that induces current in nearby conductive materials, even without direct contact. During electrosurgery, capacitive coupling happens when energy from an active electrode transfers through intact insulation to adjacent conductive instruments or tissues. The transferred energy generates heat in the unintended tissue, potentially causing burns, especially in areas not visible to the surgeon. This risk increases with higher voltage settings, longer activation times, and when instruments are placed close together in confined spaces like trocar sleeves during laparoscopic procedures. The danger is particularly significant because these injuries often occur outside the surgical field of view, leading to delayed diagnosis. To prevent such injuries, surgeons should use lower power settings when possible, avoid prolonged activation of electrosurgical instruments, ensure proper insulation of instruments, and maintain awareness of instrument positioning relative to surrounding tissues and other metal objects 1.
Some of the key factors that contribute to thermal injury from capacitive coupling include:
- Higher voltage settings
- Longer activation times
- Placement of instruments in close proximity to each other in confined spaces
- Inadequate insulation of instruments
- Lack of awareness of instrument positioning relative to surrounding tissues and other metal objects
It is essential to prioritize the prevention of thermal injuries from capacitive coupling, as they can lead to significant morbidity and mortality. By following the recommended guidelines and taking necessary precautions, surgeons can minimize the risk of thermal injuries and ensure the best possible outcomes for their patients. The most recent and highest quality study on this topic is from 2025, which provides evidence-based recommendations for the treatment of heat stroke and highlights the importance of active cooling measures and proper insulation of instruments 1.
In the context of the provided options, the correct answer is: A. Electric current transfer to organ touched by the metal torcher. This option accurately describes the mechanism of capacitive coupling and its potential to cause thermal injury. The other options do not accurately describe the cause of thermal injury from capacitive coupling. Therefore, option A is the correct answer based on the strongest and most recent evidence 1.
From the Research
Capacitive Coupling and Thermal Injury
- Capacitive coupling can cause thermal injury due to the transfer of electrical energy to the body, resulting in burns [(2,3,4)].
- This can occur even with intact instrument insulation, and the risk is increased when an open circuit is formed 4.
- The electrical energy can cause damage to tissues, leading to thermal burns, and the extent of the injury can be severe [(2,5,4)].
Mechanism of Injury
- Capacitive coupling can release stray currents into neighboring non-targeted tissues, causing indirect electrosurgical damage 3.
- The electrical response can be greater when there is increased contact with the tissue, and the risk of injury is higher with certain types of instruments and procedures [(3,4)].
Prevention and Management
- Measures to minimize capacitive coupling include thorough staff training, regular safety inspections, and strict procedure performance 3.
- The use of shielded instruments with active electrode monitoring (AEM) can help prevent electrosurgical injuries 2.
- In cases of thermal burn injury, priorities for emergency resuscitation include stabilization of airway and breathing, intravenous fluid administration, pain control, and local wound care 6.