Episode #251 Surgical Fires: The 30% Oxygen Rule

Hello and welcome back to the Anesthesia Patient Safety Podcast. My name is Alli Bechtel, and I am your host. Thank you for joining us for another show. We are returning to the February 2025 APSF Newsletter today to talk about a hot topic. That’s right we are talking about surgical fire prevention and oxygen delivery so stay tuned.

Before we dive further into the episode today, we’d like to recognize Solventum, a major corporate supporter of APSF. Solventum has generously provided unrestricted support to further our vision that “no one shall be harmed by anesthesia care”. Thank you, Solventum – we wouldn’t be able to do all that we do without you!”

Our featured article is “Assessing Fire Risk in Surgery: Why Limit Open Oxygen Delivery to 30%?”

by Mark Bruley and Jeffrey Feldman. To follow along with us, head over to APSF.org and click on the Newsletter heading. First one down is the Current Issue. Then, scroll down until you get to our featured article today. I will include the link in the show notes as well.

To help kick off the show today, we are going to hear from both of the authors. First up, we have Mark Bruley.

[Bruley] “Hi, I am Mark Bruley, a biomedical engineer and vice president emeritus for accident and forensic investigation with ECRI, a non-profit health services research organization.”

[Bechtel] I asked Bruley what got him interested in this topic. Let’s take a listen to what he had to say.

[Bruley] “I became interested in surgical fire causes and prevention in 1978 when a hospital CEO asked ECRI to investigate a surgical fire that occurred during cataract surgery. I found that the patient was receiving supplemental oxygen via a disposable face mask. The cotton surgical towels that bordered the right eye operative site became oxygen-enriched. They ignited in a large flash fire when touched accidentally by the hot wire tip of a cautery pen. Subsequently, I investigated scores of surgical fires and became passionate about preventing them.”

[Bechtel] And now we are going to hear from the Jeffrey Feldman. Here he is now.

[Feldman] “Hi, my name is Jeffrey Feldman, and I am an anesthesiologist at the Children’s Hospital of Philadelphia and member of the APSF board of directors.  I also chair the APSF committee on Technology.”

[Bechtel] I also asked Feldman why he is so interested in this topic. This is what he had to say.

[Feldman] My interest began in 2008 when I was asked to help with a joint production by APSF and ECRI of a video on preventing surgical fires.  That was my first opportunity to meet my co-author on this article Mark Bruley and learn not only about the number of people injured or killed by surgical fires, but the ability through careful practice to make it a never event.”

[Bechtel] Thank you so much to Bruley and Feldman for helping to introduce this important topic. And now it’s time to get into the article.

[Maybe include fire sounds for transition…]

We have talked about the risks of surgical fires and how to prevent this devastating complication on the show before. The APSF has an incredible resource to help increase education to help make this a never event. It is called, “Surgical and Operating Room (OR) Fires – A Preventable Problem” and includes.

The Fire Prevention Algorithm

The updated short fire prevention video

The original fire prevention and management video

Supplemental resources and more.

Head over to APSF.org and click on the patient safety resources heading. Third one down is The Surgical Fires – A Preventable Problem Resource. It has everything you need to lead a Fire Prevention Education Session at your institution.

Despite these educational resources and well-established recommendations, surgical fires continue to occur leading to preventable morbidity and mortality. One of the important recommendations that we are going to focus on today is limiting open oxygen delivery to 30%. The following organizations support this recommendation:

the American Society of Anesthesiologists

the American College of Surgeon

the Society of American Gastrointestinal and Endoscopic Surgeons

the Association of periOperative Registered Nurses

the Joint Commission

the Emergency Care Research Institute (ECRI)

the Food and Drug Administration

and the Pennsylvania Patient Safety Authority.

Investigations into surgical fires have revealed that the root cause of the overwhelming majority of serious fires is administration of oxygen from an open delivery source, like a disposable facemask or nasal cannula.

Thus, the key recommendations for surgical fire prevention are as follows:

1. Limit the delivered oxygen concentration connected to the open delivery device to 30% or less.
2. Control the airway if a greater concentration of oxygen is clinically indicated.

We also need to know what surgeries or procedures high risk are including procedures around the head, neck, and upper chest when intravenous sedation is used, and oxygen is delivered from an open source with the goal of keeping patients safe. However, this open-source oxygen delivery is what puts patients in harms way when it comes to surgical fire. For procedures with a high fire risk, how much oxygen can be administered to keep patients safe without increasing the fire risk? The recommendation is 30% oxygen concentration or less based on work done at ECRI and Mark Bruley and colleagues. So, what is the ECRI? It is a nonprofit organization of over 500 experts and over 50 years of industry experience using the nation’s largest datasets to provide insights into patient safety and savings opportunities to allow for better care overall.  Check out the link in the show notes for more information about ECRI.

Years ago, ECRI and other investigators have performed laboratory testing of the flammability of surgical drapes when exposed to room air and 80% oxygen concentration. The 30% recommendation came from surgical fire accident investigations by ECRI in the late 1970s. The team found that surface fiber flame propagation occurred in vitro on cotton surgical towel fibers and human hair in the presence of oxygen concentrations of 50% or more. This describes the rapid spread of fire from the inciting source which only happens due to the higher oxygen concentrations that create flammable conditions that would not otherwise exist. Checkout the YouTube video that is embedded in the article to watch the surface fiber flame propagation in an enriched oxygen environment. The video is from research and testing by the Royal Air Force Institute of Aviation Medicine. I will include the link in the show notes as well.

Testing of different oxygen concentrations revealed that when the oxygen concentration dropped to about 45%, flame propagation was not as likely. The authors highlight this key point that I am going to read:

“It is the oxygen-enriched atmosphere enhanced propagation that creates the two-fold risk of easier ignition of materials and subsequent very rapid spread of flames outward from the point of ignition.”

Then, when the supplemental oxygen was turned off, oxygen concentrations under the drapes dropped below 30% and the fire propagation did not occur.

So, now we know what our safe limit is for oxygen concentration for fire safety, but what about patients who may require supplemental oxygen by mask or nasal cannula when receiving IV sedation? The pulse oximeter was introduced in the late 1980s around the same time. Thus, the 30% recommendation was seen as a safe limit as long as the pulse oximeter was used to monitor oxygenation.

Let’s fast forward to the current recommendations for preventing surgical fires. No more than 30% oxygen should be delivered by an open source and the use of a supraglottic airway or endotracheal tube should be used if a greater than 30% oxygen concentration is required. For many patients with normal lung function, spontaneous ventilation, and an un-obstructed airway, 30% oxygen will ensure adequate oxygenation. Earlier guidelines recommended reducing the oxygen concentration just prior to activating an ignition source, like an electrosurgical probe, electrocautery probe, or a surgical laser, but this may place the patient at risk for hypoxemia if they required that higher concentration of oxygen. This is why it is vital to control the airway when an oxygen concentration of greater than 30% is required for fire prevention and to prevent hypoxemia. Does your anaesthesia practice include the use of an oxygen blender? Check out Figure 1 in the article for a picture of an oxygen blender device that allows you to titrate the oxygen concentration. This is the safest option when using open delivery devices for oxygen instead of 100% oxygen connected to a mask or nasal cannula.

The key takeaway is that laboratory testing has revealed that common materials in the surgical field become flammable with rapid spread of fire when oxygen is delivered by open source at concentrations of 50% or greater. There is a call to action during high fire risk procedures, that oxygen concentration delivered by open source should be limited to 30% or less.

There is a comment on the article that provides an additional consideration that 2L/min oxygen by nasal cannula which nets an alveolar oxygen concentration of about 28% is not the same as delivery of less than 30% because the oxygen concentration that is exiting the cannula around the face is 100% oxygen which supports a flammable environment there. A useful approach may be to connect the nasal cannula to the breathing circuit through an endotracheal tube adapter, close the popoff valve, and use a ratio of 7 to 1 air to oxygen. Remember, the other option is to use a blender.

We made it to the end of the article, and it is time to hear from the authors again. I also asked, “What do you envision for the future of surgical fire prevention?

Here is what Mark Bruley had to say:

[Bruley]  “There has been a decline in surgical fires, and I envision a continuing decline due to increasing awareness of preventive measures by the clinical community and by ongoing efforts of medical societies and regulatory bodies. Using data in reference number 2 of our article, I and my ECRI colleagues currently estimate the number of surgical fires in the United States to be approximately 85-105 per year out of about 60 million surgeries performed annually. This is significantly lower than our 2007 estimate of 550-650 such fires per year. I see a continuing trend downward in the incidence of this hazard.”

That is definitely some good news. And now let’s take a listen to what Jeffrey Feldman had to say:

[Feldman] “It is gratifying that the educational work by APSF, ECRI and other organizations seems to have reduced the incidence of surgical fires.  Unfortunately, preventable morbidity and mortality from surgical fires continues to occur.  There is no doubt that the root cause of most, if not all, serious fires is the continued routine use of high concentrations of oxygen by mask or nasal cannula during sedation.  Furthermore, my experience with trainees is that we continue to teach the routine use of 100% oxygen by open delivery when sedating patients.  My hope for the future is that clinicians will understand the information in this article and when there is a high risk for fire, adopt recommended practices for limiting the oxygen concentration to less than 30% or control the airway if a greater oxygen concentration is needed to prevent hypoxemia.  By following these recommendations, surgical fires can be completely eliminated.”

We are all looking forward to a future where patients are safe from surgical fires! Thank you so much to Bruley and Feldman for contributing to the show today.

If you have any questions or comments from today’s show, please email us at [email protected]. Please keep in mind that the information in this show is provided for informational purposes only and does not constitute medical or legal advice. We hope that you will visit APSF.org for detailed information and check out the show notes for links to all the topics we discussed today.

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Until next time, stay vigilant so that no one shall be harmed by anesthesia care.

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