ESU Burns from Poor Dispersive Electrode Site Preparation
Hazard Update [Health Devices Aug-Sep 1993;22(8-9):422-3]
In January 1987, ECRI reported on electrosurgical burns resulting from
poor dispersive electrode site preparation (see our Hazard Report, based on incidents
reported to and investigated by ECRI, in Health Devices, 16:35-6).
Unfortunately, these incidents, which can be easily avoided, continue to occur. This has
prompted us to update our previous report and to reemphasize the need to follow certain
In a typical incident, a burn is detected after the surgeon attempts to
activate the electrosurgical unit (ESU) several times with no effect. The burn will almost
always occur directly underneath the dispersive electrode placed on the patient (the
dispersive electrode and return electrode cable make up the return electrode). The burn
typically corresponds to a charred section on the dispersive electrode's conductive
surface resulting from high current density and arcing between the dispersive electrode
pad and the patient's skin.
An electrosurgical burn following an ESU activation that produces little
or no surgical effect typically indicates poor electrical contact between the dispersive
electrode and the patient. This can be caused by poor electrode placement, defective
materials on the electrode, dried-out conductive gel or adhesive, or inadequate site
preparation. The incidents that prompted our 1987 report and several recent incidents
occurred because the site underneath the dispersive electrode had not been shaved. An
unshaved area underneath the dispersive electrode will inhibit complete electrode-to-skin
contact, result in high electrode-to-skin contact impedance, and lead to heating of or
arcing to the tissue under the electrode.
Return electrode manufacturers are aware of this problem; they typically
provide application instructions and warning labels on their packages stating that the
area underneath the dispersive electrode should be cleaned and shaved as necessary.
However, OR scrub nurses or circulating nurses may neglect to shave the area to save time
or because they are unaware of the need for shaving or their patients object to shaving
for cosmetic reasons. Shaving may not be needed on patients (e.g., infants, children,
women) who have little or no hair at the chosen pad site, but when there is a question,
the area should be shaved.
Regardless of how the dispersive electrode is placed on the patient or how
the site underneath the pad is prepared, OR staff should be aware that inadequate surgical
effect at the active electrode site is a warning sign of poor contact impedance. OR staff
should immediately check the dispersive electrode for placement and obvious defects. If no
problems are apparent, the dispersive pad should be removed and checked for dried-out
conductive gel or adhesive, and the skin underneath the pad should be examined for signs
of high electrode-to-skin contact impedance (e.g., a pad placed over improperly cleaned or
shaved areas). If an improperly cleaned or shaved area is suspected, it should be cleaned
or shaved. Regardless of whether problems are found with the dispersive pad, a new pad
should be placed on the patient before activating the ESU.
Fatty tissue or tissue directly over bone can also impede electrosurgical
return current flow, and dispersive pads placed over these areas should be replaced with a
new pad over a muscular area, such as the anterior or lateral thigh, which is more
conductive. When this is not possible (e.g., with extremely obese patients), a second
parallel dispersive electrode may sometimes be used to increase the overall dispersive pad
surface area, decrease the electrode-to-skin contact impedance, and reduce current
density. Some ESU manufacturers provide adapters that permit users to attach two return
electrodes to their units when used with obese patients.
Several ESU manufacturers have monitoring circuits designed to detect the
quality of contact between the patient and the pad. These monitors typically alarm and
defeat ESU activation when there is insufficient contact between the patient and the
dispersive electrode (e.g., when the electrode is peeled away from the patient) or the pad
is placed over poorly conductive areas (e.g., those with large amounts of hair). Although
using a return electrode monitoring system is slightly more expensive, a good system will
significantly reduce the risks described here.
Regardless of the techniques used to prevent patient burns during
electrosurgery, proper preparation of the dispersive electrode site, proper placement of
the electrode, and vigilance by the OR staff will always be essential. By meticulously
following the procedures below, hospitals will greatly reduce the risks of burns
associated with return electrodes:
- For dispersive electrode placement, choose a flat
or relatively flat muscular area fairly close to the surgical site that will
not bear the patient's weight during surgery.
- Before placing the electrode, do the following:
- Thoroughly clean and dry the site. It is
safer to assume that the site should be shaved, rather than not
shaving it. However, on patients with little or no hair at the pad
site, shaving may not be needed.
- Check the electrode for defects, such as dried-out gel or
insufficient amounts of conductive gel or
- Place the electrode in a location where it is not
likely to come in contact with fluids.
- After applying the electrode, the operator should
run a hand over the dispersive pad to confirm uniform placement. While
smoothing, the operator's hand should move only from the outside to the
inside of the pad so that no gel is forced out from underneath it.
- Always check the dispersive electrode site whenever the ESU fails to
produce the desired effect.
- Electrodes, Electrosurgical, Return [11-500]
- Electrosurgical Units [11-490]
- Electrosurgical Units, Bipolar [18-230]
- Electrosurgical Units, Monopolar [18-299]
- Electrosurgical Units, Monopolar/Bipolar [18-231]
Cause of Device-Related Incident
User errors: Failure to read label;
Inappropriate reliance on an automated feature; Incorrect clinical use
Mechanism of Injury or Death