Protect Patients During Electrosurgery

Electrosurgical devices are used in virtually every operating room across the country, so it’s worrisome that surgeons and surgical teams don’t receive formal training on how the technology works — especially when even a minor mishap can result in significant patient burns and life-threatening fires. The responsibility lies with everyone in the OR to make sure electrosurgery instruments are used correctly and cared for properly. Surgical teams who understand the patterns of complications that occur with these instruments will be able to break the cycle of avoidable patient harm.

A basic understanding of electrosurgery should begin with knowing the difference between monopolar and bipolar instrumentation.

• Monopolar. The monopolar circuit is comprised of the electrosurgery generator, active electrode and dispersive electrode. Variables that impact tissue effect include the power setting (in watts) of the generator, dwell time (how long electrosurgery devices are activated), current density, generator mode and the proximity of tissue to the active electrode. 

Monopolar instruments can be set to two modes: cut and coagulation. In cut mode, a higher current is continuously applied to tissue at a lower voltage. In coagulation mode, a lower current is delivered with intermittent pauses at a much higher voltage. Continuous cutting results in a rapid rise in temperature with explosive vaporization of tissue and minimal lateral thermal spread. Coagulation generates less heat with higher voltage, which results in maximum hemostasis and increased risk of injury to surrounding tissue.

Stray energy transfer is often thought to occur only along the shaft or at the tip of active electrodes in the surgical field, but it can also occur along the wires that connect electrosurgery instruments to the generator. Laying wires against conductive materials in the OR increases the risk of energy transferring to that material. Surgeons therefore need to arrange members of the surgical team and organize the wires of monopolar devices to ensure they’re not near implantable electronic devices or other conductive materials such as esophageal temperature probes, EKG leads and nerve monitors used during lumbar spine operations.

The leading edge of dispersive electrodes heat up when devices are activated. That can lead to the transfer of stray energy if the electrodes are placed over well-vascularized tissue, which has low resistance, or conductive materials in the surgical field such as joint implants. The amount of heat generated by electrosurgery devices is proportional to the current density squared; as the area that current passes through decreases, the relative amount of temperature that’s generated is squared. That means there’s more than a 10,000 times temperature difference between the surface area of a dispersive electrode and the tip of an active electrode.

• Bipolar. These devices use a lower amount of voltage than monopolar tools to achieve the desired tissue effect. The proximity of the active and dispersive electrodes at the distal tip of a bipolar instrument creates a shorter path for the current to travel, which reduces the risk of collateral injury from stray energy. The grounding and the active electrodes are housed at the tip of bipolar instruments, which act as jaws or forceps to grab tissue.

Advanced bipolar instruments deliver energy through defined algorithms to achieve more exact clinical effect on tissue. Bipolar instruments are considered safer than monopolar devices because they employ lower voltage, which is the prime contributing factor to stray energy complications. However, bipolar instruments dissect tissue much differently that monopolar devices, which have a much more facile tip with which to work.