Cause of Device-Related Incident
User errors

Clinical Specialty or Hospital Department
Anesthesia; Clinical/Biomedical Engineering; 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); Fire

Support System Failures
*Not stated

Tampering and/or Sabotage
*Not stated

User Errors
Failure to read label; Incorrect clinical use

UMDNS
Electrodes, Electrosurgical, Active [16-860]; Electrosurgical Units [11-490]

Ignition of Debris on Active Electrosurgical Electrodes



Hazard [Health Devices Sep-Oct 1998;27(9-10):367-70]

Problem

A member hospital reports that flames briefly flashed from the tip of an active electrosurgical electrode during a tonsillectomy. The patient was not harmed and no surrounding materials caught fire, but the risk that the fire could have spread or caused significant injury certainly existed. After the flash, staff noted that the shaft insulation near the tip of the electrode was badly melted and therefore suspected that a defect in the electrode might have initiated the fire.

While the reported problem occurred with an electrode extension blade, ECRI has investigated similar cases in which other types of active electrodes, such as suction/coagulator probes, were being used.

Discussion

Identifying the Cause

Based on ECRI's experience with electrosurgery and in investigating surgical fires, we concluded that it was unlikely that any defect in the electrode itself would have started the fire. We have investigated numerous incidents, many of them involving severe patient injuries, in which sponges or tracheal tubes in the patient's mouth, nose, or throat were ignited under circumstances similar to those described in this report. In several of these cases, defective active electrodes were suspected as the ignition source, but our investigations revealed that these fires were actually started by ignition of tissue debris or other flammable material on the electrode tip. In each case, ignition was possible, in part, because of locally elevated oxygen concentrations. We concluded that the brief burst of flames in the reported incident was caused by similar circumstances—namely, the ignition of tissue debris on the electrode tip while the tip was in an area with an elevated oxygen concentration.

Contrary to many reports of surgical fires, the active electrode itself is unlikely to burn. This is due to its metal and plastic construction. While some plastics will burn, most of the plastics used in the manufacture of active electrodes and tracheal tubes have such high ignition temperatures that they will not burn in surgical circumstances—except in the presence of another fire or, perhaps, laser energy. The damage to the active electrode insulation reported in this incident was likely caused by the heat of the flame or by excessive resistive heating of the metal electrode tip resulting from a buildup of charred tissue debris, or eschar, on the tip.

Avoiding Similar Occurrences

Strategies for avoiding and extinguishing fires typically focus on controlling or eliminating one or more of the three factors required for combustion: an ignition source, a fuel source, and an oxygen source. Complicating matters during monopolar electrosurgery is the fact that one of the combustion factors, an ignition source, will always be present.

The cutting and arcing coagulation techniques used during monopolar electrosurgery require that electrical sparks be produced at the active electrode to achieve the desired tissue effect. Under certain circumstances (e.g., in an oxygen-enriched atmosphere), these sparks could ignite nearby fuels such as sponges, tracheal tubes, or drapes. Most surgeons are well aware of this possibility and know they can reduce the risk of combustion by keeping the electrode tip away from ignitable fuels. Less well known, however, is the fact that tissue adhering to the electrode can itself become an ignitable fuel.

The transformation of tissue into a fuel occurs when excessive heating of the electrode tip causes sizable pieces of tissue to stick to the electrode surface. Sticking is most likely to occur when contact with tissue is made during use of an arcing technique, such as "spray" coagulation, because of the tremendous heat generated at the tip during such activations. (Sticking can occur even several seconds after electrosurgical unit [ESU] activation because the heat in the electrode tip does not dissipate immediately.) With additional use, the electrode tip remains hot, transforming the tissue debris on its surface into a charred material called eschar. With sufficient heating, eschar can become a glowing ember and pose a fire hazard both as an ignition source and as a fuel. Exacerbating this situation is the fact that the eschar coating will impede electrosurgical current across the electrode tip, which in turn will increase the resistive heating of the tip.

Surgeons can minimize the likelihood of excessive heating of the electrode tip and of eschar buildup on the tip by selecting ESU modes prudently and by cleaning the tip when needed. We discuss these strategies in detail in Recommendation 2, below.

While surgical staff cannot completely remove the risks presented by the electrode as an ignition source, they can usually control the availability of fuel and oxygen at the surgical site. In addition to eschar, other fuel sources that have contributed to fires we investigated—but that could have been eliminated from the procedure—include dry cotton sponges and segments of latex rubber catheters (which users slipped over the active electrode to extend the insulation). In the first example, wetting and wringing out the cotton sponges before using them would have dramatically reduced their flammability without significantly reducing blood absorption. In the second example, the electrode simply should not have been modified, especially with a material such as latex rubber, which—although it may have seemed like an appropriate insulating material—is actually highly flammable. (Note that modifying electrodes may increase the healthcare provider's liability should a fire or other accident occur.)

With respect to oxygen sources, most ESU activations do not occur in the immediate vicinity of an elevated oxygen concentration. However, some procedures will require that electrosurgery be applied in places where an elevated oxygen concentration is likely to be present (e.g., in the throat). In these cases, certain precautions can be taken to reduce the risk of fire. For example, during surgery in the throat or mouth, the surgeon will typically use a tracheal tube with a balloonlike cuff that is inflated to occlude the airway surrounding the tube; this cuff prevents oxygen from leaking from the airway into the throat and mouth. But in some procedures (e.g., on pediatric patients), cuffed tracheal tubes cannot be used because of anatomical limitations. When cuffless tracheal tubes must be used, clinicians will typically pack the airway surrounding the tracheal tube with gauze or sponges to minimize oxygen leakage. However, this technique is not always effective in preventing oxygen from leaking into the throat and mouth. To reduce the risk of fire in such situations, we advise that the surgical staff take steps such as those described in Recommendation 5, below.

Recommendations

  1. Alert operating room personnel that tissue buildup on the tip of active electrosurgical electrodes poses a fire hazard and that the risk of fire is significantly greater in locations where an elevated oxygen concentration is likely to be present, such as in the throat and mouth.
  2. Take the following steps to avoid eschar buildup on the tips of active electrodes (such as suction/coagulators):
    • Use tip-cleaning aids to clean electrode tips as needed. Abrasive pads are available for cleaning standard electrodes. For cleaning "nonstick" electrodes, we recommend using a damp sponge instead (abrasive pads will erode Teflon and silicone nonstick electrode coatings).
    • Minimize heating of the active electrode tip by using short ESU activations at the minimum power setting necessary to produce the desired effect.
    • Allow sufficient time for heat in the active electrode tip to dissipate 1) between activations and 2) before touching it to tissue after the electrode has been activated using an arcing technique.
    • Avoid using ESU modes intended for arcing coagulation (e.g., Coag, Spray, Fulgurate) during cutting and contact coagulation techniques. If used for these techniques, arcing coagulation modes will produce spattering of debris and cause tissue to stick to the electrode tip. Modes appropriate for cutting are typically labeled Pure Cut or Blend. Modes intended for contact coagulation are typically labeled Desiccate or Soft Coag, but cutting modes are also appropriate for this application.
    • Do not modify or add to the insulation of active electrodes. Contact your supplier or ECRI if you need help obtaining an electrode tip design that is not currently available to you.
    • Minimize the flammability of materials that need to be present where electrosurgery is to be applied. Sponges and gauze packing should be wetted and wrung out before use.
    • Ensure that oxygen concentration is not elevated in any area where electrosurgery will be applied. One method for minimizing oxygen levels is to ventilate the patient with air or a low oxygen concentration, instead of a high concentration, for at least one minute before ESU activation. During surgery in the oropharyngeal cavity, another method is to use suction to scavenge residual oxygen from the mouth.

ECRI encourages hospitals to make this Hazard Report and other instructional material on electrosurgery available to surgeons and OR nurses. We also stress the importance of providing periodic instruction on the rudiments of electrosurgery, as required by Section 7-6.5 of the National Fire Protection Association's Standard for Health Care Facilities. Furthermore, ECRI advocates advanced training for clinicians in techniques that optimize the safety and effectiveness of electrosurgery. For additional information and recommendations on the topics covered in this article, refer to our earlier Hazard Report, "Fires from Oxygen Use during Head and Neck Surgery," in Health Devices 24(4), April 1995.

UMDNS Terms

  • Electrodes, Electrosurgical, Active [16-860]
  • Electrosurgical Units [11-490]

Cause of Device-Related Incident

User Errors: Failure to read label; Incorrect clinical use

Mechanism of Injury or Death

Fire; Burn (thermal)


[Home]    [About]    [Help]    [Site Map]
Copyright © 2017 ECRI
All rights reserved
www.ecri.org