Letter to the Editor With Reply

Risk of Fires With Eye Surgery Under MAC

I have been a part-time cardiac anesthesiologist for many years and also practice in a couple of ambulatory surgery centers providing anesthesia for eye surgeries in a large city. I have been very lucky to be able to do both academic cardiac anesthesia and maintain a busy private practice over all these years.

The APSF has done a very good job in calling attention to the risk of fires in the OR and defining the necessary requirements. I am afraid that the recommendations may lead anesthesiologists to avoid insufflation under the drapes for cataract surgery patients, and I think this would be a mistake.

There is a debate in our practice, for which I am seeking your input. The question is if you consider a cataract patient (conscious sedation and peribulbar block) with a drape system that seals around the eye, Betadine prep solution (ample time to dry), and no use of electrocautery, at risk for a surgical fire? If the surgeon uses bipolar cautery or “pencil point” disposable cautery in one out of 20 cases, does that case qualify as a risk for fire? We use a combination drape support and gas delivery device (a long metal malleable arm that has a central conduit to deliver gases to its distal end), which can deliver oxygen or air or any combination we connect to it.

Some of our partners interpret your Fire Prevention Algorithm to mean that we should not insufflate anything under the drapes, thus allowing the patient to breathe only the “room air.” Some believe that, at the very least, we should be insufflating air in order to decrease the rebreathing of carbon dioxide. Others believe that we can safely insufflate oxygen since we have a closed draping system and very rarely use any cautery—and never any type other than bipolar or “pencil point” disposable cautery.

I cannot help but think of the existing safety record my practice has had insufflating oxygen. In the last 27 years we have done more than 500,000 cases without a fire. That is certainly an impressive safety record. There are well over 2 million cataract operations performed in the US annually. My one concern in the existing recommendations, again, is that if nothing is insufflated under the drapes (which cover the nose and mouth) there will be significant rebreathing and hypercarbia. Will we have enough hypercarbia on a very rare occasion (at least 1 in 500,000 would be worse than my existing fire safety record) that we increase cerebral blood flow enough to have a bleed in the head, or enough to produce significant acidosis causing a serious arrhythmia or adverse event?

Perhaps you can all discuss whether or not you want to specifically say that air or an oxygen concentration of 30% or less should be insufflated when a patient’s nose and mouth are covered by an impermeable drape to decrease the incidence and possible complications of rebreathing and hypercarbia?

Please let us know your opinion.
Thanks very much.

Name withheld by request.
New York, NY

Experts Respond: Occlusive Drapes Unreliable as O2 Barrier: Insufflate With Air or <30% FiO2 for Patient Comfort

Assessing the risk of fire is all about the combination of the elements of the fire triad: oxygen, heat source, and fuel.

A systematic approach can be helpful in assessing the fire risk in your specific circumstance:

#1 Oxygen: Using occlusive drapes may lead to a false sense of security of isolating the oxygen from the surgical field since small gaps or creases may exist in the drapes and allow oxygen to enter the field and enrich the local oxygen concentration thereby increasing the fire risk.

Regarding the use of the conduit you describe to insufflate under the drapes, is the insufflation for patient comfort or for oxygen supplementation? If used solely for patient comfort and to eliminate rebreathing of carbon dioxide, then medical air should work well. The intention of the algorithm was not to preclude people from insufflating air under the drapes, which can be useful both for CO2 elimination and patient comfort. If oxygen supplementation is needed to maintain adequate saturation then blended mixtures of air and up to 30% oxygen pose no acceleration of combustion. Insufflation with pure oxygen is hazardous and creates a high-risk situation with respect to surgical fires.

An important message from both the APSF and ECRI work on fire prevention is that there is an increased risk of a fire when providing 100% oxygen, especially for procedures above the xiphoid. Exposing the patient to that increased fire risk is generally not clinically warranted. Most patients will tolerate careful sedation while breathing room air or air that is slightly enriched with oxygen to no more than 30% concentration. Even well-trained anesthesia professionals find it challenging to break the habit of providing 100% oxygen by open delivery during sedation cases. Oxygen given in concentrations greater than 30% should be for clear patient benefit, with an understanding of the increased risk for fire, and not solely because it is a long-standing practice and is simpler than alternatives such as using an oxygen blender or securing the airway with an endotracheal tube or supraglottic airway device.

#2 Heat Source: If cautery is not used, then the heat source is not present and hence no fire risk is present. Bipolar tips are not usually considered ignition sources, but in an atmosphere which is oxygen enriched beyond 30%, the threshold of ignition of most fuels is decreased, so while “safer,” we cannot completely exclude their capacity to start a fire. As for using a cautery device in only 1 of 20 cases, one should consider that surgical fires are rare occurrences; however, the combination of the elements of the fire triad always pose the risk for a fire. A pencil tip cautery was recently implicated in a fire in the emergency center in Delhi, CA at Emanuel Medical Center involving oxygen supplementation. http://www.modbee.com/2012/03/08/v-print/2104480 cauterizing-tool-ignited-womans.html

#3 Fuel: Alcohol free prep solutions such as povidone-iodine are not flammable so drying time does not matter from a fire perspective, only from an antimicrobial one.
Thank you for taking the time to pursue this issue and contribute your extensive experience and thoughtful clinical expertise. The APSF Newsletter offers a very useful forum for vetting safety recommendations. One of the challenges to these recommendations is anticipating every clinical situation and how the recommendations should be best applied. That is of course why there are recommendations as there is no substitute for a thoughtful clinician making decisions about the best care for an individual patient. We are appreciative of the opportunity to publish the content of this dialogue in the APSF Newsletter.

As a final note, we are glad that surgical teams like yours are discussing surgical fires and are thinking of plausible ways to reduce to the risk. Kudos to your group for their safety concerns.

Jeff Feldman, MD
The Children’s Hospital of Philadelphia
Philadelphia, PA

Charles Cowles, MD
The University of Texas MD Anderson Cancer Center
Houston, TX