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, as supported by the principles of electric shock and thermal injury 1. This occurs during electrosurgery when the active electrode's insulation is intact but in close proximity to metal instruments or tissue. The electrical energy generates heat in the unintended pathway, which can cause burns at distant sites where the patient contacts other conductive surfaces.
- Key factors contributing to the severity of thermal injury from capacitive coupling include:
- Power settings
- Duration of activation
- Proximity of the active electrode to other conductive objects The high-frequency alternating current creates capacitance between conductors separated by insulation, allowing energy transfer without direct contact, which is a critical aspect of how capacitive coupling leads to thermal injury, and is related to the conversion of electric energy into heat energy as current passes through body tissues 1. To prevent such injuries, surgeons should:
- Avoid parallel placement of instruments
- Use lower power settings when possible
- Ensure proper patient positioning to minimize contact with conductive surfaces
- Regularly inspect instrument insulation
- Use active electrode monitoring systems to further reduce the risk of capacitive coupling injuries. In the context of thermal injuries, understanding the causes and prevention strategies is crucial for minimizing damaging physical, functional, cosmetic, and psychosocial consequences, as highlighted in recent guidelines 1.
From the Research
Capacitive Coupling and Thermal Injury
- Capacitive coupling can cause thermal injury by releasing stray currents into neighboring non-targeted tissues, even with intact instrument insulation 2.
- This can occur during monopolar laparoscopy, where the electrical response becomes greater with increased contact with the cystic wall 2.
- Insulation failure and capacitive coupling are the most common reasons for electrosurgical injury during laparoscopic procedures 3.
- Capacitive coupling can lead to electrical skin burn injury during laparoscopic surgery, even with intact insulation, if an open circuit is formed 4.
- The mechanisms of burn injuries during laparoscopy include direct contact, electric arc, insulation failure, direct or capacitive coupling 5.
Prevention of Capacitive Coupling
- Appropriate measures are available for minimizing capacitive coupling, including thorough staff training, regular safety inspections, and strict procedure performance 2.
- The use of advanced technology, such as active electrode monitoring, can help address the risks of capacitive coupling 3.
- Perioperative nurses should standardize processes, preoperatively assess the risks for electrosurgical injuries, and participate in education activities on electrosurgical safety to help prevent injuries from occurring 6.
- Careful manipulation must be taken to avoid creating an open circuit when using electrocautery to prevent capacitive coupling related to electrical skin burn 4.
Possible Causes of Thermal Injury
- The possible causes of thermal injury due to capacitive coupling are:
- A. Electric current transfer to organ touched by the metal torcher
- B. Sandwiching
- C. Wrong energy
- D. Failure of insulation However, according to the studies, the correct answer is related to the release of stray currents into neighboring non-targeted tissues, even with intact instrument insulation, which is not explicitly listed among the options. The closest related option would be D. Failure of insulation, but it is essential to note that insulation failure is not the only cause, as capacitive coupling can occur even with intact insulation 2, 3, 4.