Cause of Device-Related Incident
User errors

Clinical Specialty or Hospital Department
Obstetrics and Gynecology; OR / Surgery

Device Factors
*Not stated

Document Type
Hazard Reports

External Factors
*Not stated

Mechanism of Injury or Death
Burn (electrical, thermal, chemical)

Support System Failures
*Not stated

Tampering and/or Sabotage
*Not stated

User Errors
Failure to read label; Inappropriate reliance on an automated feature; Incorrect clinical use

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]

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[1]: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 precautions.

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:

  1. 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.
  2. 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 adhesive.
  3. Place the electrode in a location where it is not likely to come in contact with fluids.
  4. 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.
  5. 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


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