Hazard [Health Devices Sep-Oct 1998;27(9-10):367-70]
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.
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
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,
- 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.
- Take the following steps to
avoid eschar buildup on the tips of active electrodes (such as
- 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
- 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
- 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
- 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
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),
- Electrodes, Electrosurgical, Active [16-860]
- Electrosurgical Units [11-490]
Cause of Device-Related
User Errors: Failure to read label; Incorrect clinical use
Mechanism of Injury or
Fire; Burn (thermal)