ESU Burns from Poor Return Electrode Site Preparation
Hazard [Health Devices Jan 1987;16(1):35-6]
ECRI continues to receive problem reports and to investigate incidents of
burns occurring underneath electrosurgical dispersive electrodes. In the incident reported
here, a burn was detected after the surgeon attempted to activate an electrosurgical unit
(ESU) several times with no surgical effect. The burn occurred directly underneath the
dispersive (return) electrode and corresponded to a charred section near the edge of the
electrode's conductive adhesive surface, which indicates that arcing probably occurred
between that section of the dispersive electrode 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, inadequate site
preparation, defective materials on the return electrode, or dried-out conductive gel or
In the incident described above, the dispersive pad appeared to have been
adequately attached to the patient, the electrode did not appear to be defective (other
than the charred section of the pad), and the conductive adhesive was not dried out.
However, the site underneath the pad had not been shaved. The patient's hair most likely
inhibited complete dispersive electrode skin contact, resulting in a high patient
electrode contact impedance. The burn most likely occurred at a small contact point
between the patient's skin and the conductive layer of the return electrode.
We are aware of several other electrosurgical burns attributed to improper
shaving of the area underneath the patient return electrode. Dispersive electrode
manufacturers are aware of this problem and provide application instructions and warning
labels on their packages, which typically state that the area underneath the dispersive
electrode should be cleaned and shaved as necessary. However, OR scrub or circulating
nurses may neglect to shave the area to save time, because they are unaware of the need
for shaving, or because patients object to shaving for cosmetic reasons.
Regardless of how the return electrode is placed on the patient or how the
site underneath the pad is prepared, OR staff should be aware of the warning signs of poor
contact impedance. If inadequate surgical effect at the active electrode site occurs, OR
staff should immediately check the return electrode for pad 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 patient electrode 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 thigh, which is more conductive. When
this is not possible (e.g., with obese patients), a second parallel return electrode may
sometimes be used to increase the overall dispersive pad surface area, decrease the
patient electrode 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.
Two manufacturers' circuits are designed to detect the quality of the
contact between the patient and the pad. One circuit is built into the manufacturer's
ESUs, and the other is a module that can be used with most ESUs. We evaluated these
systems, called contact quality monitors, in Health Devices 14:115-31 (1985). These
monitors are designed to detect insufficient contact between the patient and the return
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 contact quality monitoring system is more expensive than a standard
electrosurgical system, a good one may provide benefits for hospitals that experience
several electrosurgical burns per year.
Regardless of what techniques are used to prevent patient burns during
electrosurgery, they will not replace proper preparation of the return electrode site and
proper placement of the electrode. By performing the following procedures, hospitals will
greatly reduce the risk of these burns:
- Choose a flat or relatively flat muscular area
fairly close to the surgical site that will not bear the patient's weight
during surgery for dispersive electrode placement.
- Before placing the electrode, thoroughly clean and
dry the site. It is safer to assume that you should shave the site than not
- Place the electrode in a location where it is not
likely to come into contact with fluids.
- Before placing the electrode, check it for defects
such as dried-out or insufficient amounts of conductive gel or adhesive.
- 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 the
Electrosurgical, Return [11-500]
Cause of Device-Related Incident
User errors: Failure to read label; Improper connection; Incorrect clinical use
Mechanism of Injury or Death