From the Guidelines
The answer is A. Electric current transfer to organ touched by the metal torcher. Capacitive coupling occurs when electrical energy is transferred between two conductive objects without direct contact, through an electromagnetic field. In surgical settings, this happens when electrical current from an active electrode creates an electromagnetic field that induces current in nearby metal instruments. If these instruments are in contact with tissue, the transferred energy can cause unintended thermal injury to organs or structures. This mechanism differs from insulation failure (which involves direct current leakage through damaged insulation), wrong energy settings (which cause direct tissue damage from the primary current), or sandwiching (which refers to tissue compressed between instruments). Capacitive coupling is particularly dangerous during laparoscopic procedures where long, thin instruments can act as conductors and transfer energy to structures not in the surgeon's field of view, as noted in studies discussing electromagnetic interference in medical settings 1. Key considerations to prevent such injuries include careful handling of electrical instruments and monitoring of patients, especially those with pacemakers, during procedures involving electrocautery or other sources of electromagnetic fields 1. Moreover, maintaining normothermia during surgery is crucial, as hypothermia can increase the risk of surgical site infections, according to recent guidelines on intraoperative surgical site infection control 1. However, the primary concern with capacitive coupling remains the potential for thermal injury due to the unintended transfer of electrical energy.
From the Research
Capacitive Coupling and Thermal Injury
- Capacitive coupling can cause thermal injury during laparoscopic surgery, as it can release stray currents into neighboring non-targeted tissues 2.
- This can occur even with intact instrument insulation, and can be increased by factors such as increased contact with the cystic wall 2.
- Capacitive coupling can lead to electrical skin burn injury during laparoscopic surgery, and can be measured by changes in temperature, current, voltage, and impedance around the trocar 3.
- The use of electrocautery can increase the risk of capacitive coupling, and careful manipulation is necessary to avoid creating an open circuit and preventing capacitive coupling related to electrical skin burn 3.
Causes of Thermal Injury
- Capacitive coupling is a cause of thermal injury, and can occur through the release of stray currents into neighboring non-targeted tissues 2, 3.
- Insulation failure can also contribute to thermal injury, as it can allow electrical current to escape and cause burns 4, 5.
- Direct coupling and capacitive coupling around active electrodes can also cause serious burns and tissue damage to patients undergoing laparoscopic procedures 5.
- The options provided, including electric current transfer to organ touched by the metal torcher, sandwiching, wrong energy, and failure of insulation, are all potential causes of thermal injury, but capacitive coupling is a specific cause that can occur even with intact instrument insulation 2, 3.