🫁 OR Fire Safety

The Operating Room Fire Triangle — Oxidizer, Fuel, and Ignition in Airway Surgery

Combustion requires three elements present simultaneously: an oxidizer, a fuel, and an ignition source. Remove any one and fire cannot occur. In the operating room, this simple physical principle becomes a life-and-death safety framework — because during head, neck, and airway surgery, all three elements are routinely brought into close proximity by the very nature of the procedure: supplemental oxygen is delivered near an open surgical field, flammable materials surround the patient, and electrosurgical or laser devices are activated inches from the airway.

• ~550–650: Surgical fires per year (US) (estimated, FDA/ECRI)
• ~85%: Occur in head/neck/upper chest (oxygen-enriched field)
• 3: Fire triangle elements required (oxidizer + fuel + ignition)
• >90%: Fires preventable with protocol (ASA Practice Advisory estimate)

Anatomy of the fire triangle in the surgical field

The classic fire triangle (sometimes drawn as a tetrahedron when a self-sustaining chemical chain reaction is included) describes the minimum conditions for combustion:

• Oxidizer: any agent that supports combustion by supplying oxygen. In the OR this is overwhelmingly supplemental O2 delivered by nasal cannula, face mask, or through an endotracheal tube, sometimes combined with nitrous oxide (N2O), which itself supports combustion despite not being flammable itself.

• Fuel: any combustible material in or near the field. Surgical drapes (especially non-fire-resistant paper or fabric), the endotracheal tube itself (PVC tubing ignites and can act as a blowtorch, directing flame down the airway), alcohol-based skin preparation solutions before they are fully dry, patient hair, sponges, and dressings.

• Ignition source: any device capable of generating heat sufficient to ignite the fuel in the presence of the oxidizer. Electrocautery (monopolar "Bovie") units are implicated in the majority of OR fires; surgical lasers (CO2, KTP, Nd:YAG) used for airway and laryngeal procedures are a smaller but especially dangerous category because they are frequently used directly inside an oxygen-enriched airway.

What makes head and neck surgery uniquely hazardous is spatial: the oxidizer source (open or semi-open oxygen delivery near the face), the fuel (drapes tenting over the face, an ETT in the airway), and the ignition source (cautery or laser at the surgical site) are all confined to a volume of a few centimeters, often under a drape that can trap oxygen and create a locally oxygen-enriched "tent" atmosphere far above room-air concentration.

Fire triangle and prevention checklist, in one line: No fire without all three — oxidizer, fuel, ignition — together, at once. Break the triangle by minimizing FiO2 near an open source, keeping fuel away or fully dried, and never activating an energy device until the team confirms it is safe. Any one broken link stops the fire before it starts.

Epidemiology — why head, neck, and upper-chest cases dominate fire statistics

Retrospective analyses of surgical fire case series (ECRI Institute, ASA Closed Claims Project) consistently find that the overwhelming majority of OR fires occur during procedures involving the head, neck, or upper chest performed under monitored anesthesia care (MAC) or general anesthesia with an oxygen-enriched atmosphere near the surgical site — tonsillectomy, tracheostomy, tumor excision of the face or neck, and laser airway procedures for laryngeal papillomas or subglottic stenosis chief among them.

The pattern is explained by geometry, not chance: these are precisely the cases where an open or semi-open oxygen source (nasal cannula, face mask, or a leaking circuit near an ETT), a field draped in flammable material, and an activated ignition device are unavoidably co-located. Abdominal or extremity surgery, by contrast, rarely places an oxygen source anywhere near the operative field, so the oxidizer leg of the triangle is essentially absent.

The severity of airway fires is also disproportionate: because the fuel (an ignited ETT) is inside the patient's airway when combustion starts, injury is not limited to surface burns — it can include thermal injury to the trachea, bronchi, and lung parenchyma, with a risk of long-term airway stenosis or fatal outcome if not managed within seconds.

Identifying High-Risk Procedures — Open Oxygen Sources Near an Activated Ignition Device

Not every operation carries meaningful fire risk. The ASA Practice Advisory on operating room fires directs teams to explicitly classify each case before incision: does the procedure involve an oxygen-enriched atmosphere at or above the level of the xiphoid, is an ignition source (electrocautery or laser) planned near that atmosphere, and is a flammable fuel present in the field? When the answer to all three is yes, the case is designated high risk and a specific fire-prevention checklist is triggered.

• 3: Highest-risk procedure types (tracheostomy, tonsillectomy, laser airway)
• Majority: MAC cases with supplemental O2 (of reported facial/airway fires)
• Electrocautery: Ignition device implicated (in most OR fire case series)
• ~30%: Risk rises sharply above FiO2 (under drapes/tenting)

The high-risk triad — surgical site, anesthetic technique, and energy device

A case is flagged as high fire risk when three conditions align:

1. Surgical site at or above the xiphoid — face, scalp, neck, upper airway, or upper chest — where an oxygen delivery device can realistically create a locally enriched atmosphere.

2. Anesthetic technique delivering supplemental oxygen in an open or semi-open fashion — nasal cannula or face mask during monitored anesthesia care, or an uncuffed/leaking airway during general anesthesia — rather than a fully closed-circuit ventilated airway where oxygen is contained.

3. An ignition source planned for use in or near that field — electrocautery for hemostasis or tissue dissection, or a surgical laser for tumor ablation, vocal cord surgery, or airway stenosis treatment.

Tracheostomy is a classic example: the airway is entered surgically while the patient may still be receiving high FiO2 through the original ETT, and electrocautery is frequently used to control bleeding through subcutaneous fat and strap muscle just before or during entry into the trachea — placing an ignition source directly adjacent to an oxygen-rich airway lumen at the moment of opening.

Tonsillectomy and adenoidectomy performed with electrocautery dissection in a patient breathing supplemental oxygen by nasal cannula (common in pediatric MAC cases) is the single most frequently cited high-risk combination in closed-claims fire analyses, because the oral cavity, oropharyngeal packing, and surrounding drapes can pool exhaled and delivered oxygen.

Laser airway surgery for papillomas, webs, or subglottic stenosis is a distinct high-risk category: the laser is used inside or immediately adjacent to the endotracheal tube itself, so the fuel (PVC or silicone ETT) and the ignition source occupy the same few millimeters, with oxygen flowing directly through the tube lumen.

Scoring risk — how the FiO2/ignition interaction drives the fire risk gauge

A simplified operational risk model — reflected in the risk gauge in this simulation — treats fire risk as rising with both the local oxygen concentration and the intensity/proximity of the ignition source, with a synergistic penalty when both are elevated simultaneously (because the two factors do not simply add — an activated cautery tip in a 21% room-air field is a nuisance, but the same tip in a 60% oxygen tent is an ignition event waiting to happen).

Practically, anesthesia and surgical teams reduce this score preoperatively by agreeing on the lowest safe FiO2 for the case, confirming whether a closed or open airway will be used, and explicitly discussing when and how the ignition device will be used relative to oxygen flow — the essence of the fire risk timeout embedded in the WHO Surgical Safety Checklist and institutional fire-risk checklists.

Prevention Strategies — Breaking the Fire Triangle Before Incision

Because all three legs of the fire triangle must be present for ignition, the most effective fire safety strategy is to eliminate or minimize any one of them rather than relying on rapid response after ignition. The ASA Practice Advisory on Operating Room Fires (updated 2013, reaffirmed since) organizes prevention around oxidizer control, fuel management, and ignition-source discipline, implemented through explicit team communication before any energy device is activated near the airway.

• <30%: Target FiO2 under drapes (air-oxygen blend when feasible)
• ≥3 min: Prep solution dry time (before draping, alcohol-based agents)
• Mandatory: Laser-safe ETT requirement (for laser airway procedures)
• Every activation: Communication checkpoint (before cautery/laser near airway)

Controlling the oxidizer — minimizing and containing supplemental oxygen

The single most modifiable leg of the fire triangle is the oxidizer, because oxygen concentration near the surgical field can usually be titrated down without compromising patient safety, unlike fuel (drapes and the ETT must be present) or ignition (cautery/laser is often clinically necessary).

Key oxidizer-control measures:

• Use the lowest FiO2 that maintains adequate oxygen saturation — blending air with oxygen rather than delivering 100% O2 by open face mask or nasal cannula whenever the patient tolerates it.

• Avoid closed-tent oxygen delivery under surgical drapes — an open oxygen source under a drape can raise local oxygen concentration to well above 21% (and above 30% is considered a meaningfully elevated risk zone) because the drape traps the gas rather than allowing it to disperse into room air.

• When feasible during MAC cases near the face, use a scavenging or open delivery system that allows entrained room air to dilute the oxygen, and coordinate with the surgeon to keep drapes elevated off the face to prevent gas pooling.

• During general anesthesia with a secured, cuffed airway, oxygen is contained within the circuit and the fire risk from the oxidizer leg is substantially reduced compared to open MAC oxygen delivery — one reason some high-risk head/neck cases are preferentially managed with a secured airway when clinically appropriate.

Managing fuel and disciplining the ignition source

Fuel management:

• Allow alcohol-based skin preparation solutions to fully air-dry before draping — wet or partially dried prep is a well-documented ignition point, since alcohol vapor trapped under a drape is highly flammable even at brief cautery contact.

• Use fire-resistant drape materials where available and avoid unnecessary pooling of prep solution in skin folds or hair, which prolongs drying time.

• For laser airway surgery, use a laser-resistant (laser-safe) endotracheal tube — typically a metal-wrapped or specially coated tube designed to resist perforation by the laser beam, with the cuff filled with saline (often tinted with dye) rather than air, so that any cuff perforation is immediately visible and self-extinguishing.

Ignition-source discipline:

• Before activating electrocautery or laser near the head, neck, or airway, the operator explicitly confirms with anesthesia that FiO2 has been minimized and, when relevant, that the airway is secured — a verbal timeout embedded into the procedural pause.

• Electrocautery is kept in standby mode and only activated when the tip is in contact with tissue and away from any pooled prep solution or oxygen-rich gas plume.

• Surgeons avoid activating the ignition source immediately after a burst of supplemental oxygen delivery or in the presence of visible oxygen tenting under the drape.

Together, these measures are the practical content of the fire risk timeout: a structured moment, ideally built into the surgical pause or WHO checklist, where the entire team confirms the fire triangle has been actively broken before the case proceeds.

Fire Recognition and the Immediate OR Fire Response Algorithm

Despite best prevention efforts, an OR fire can still occur — and when it does, the difference between a minor incident and a catastrophic airway injury is measured in seconds. The ASA has codified a standardized fire response algorithm that every operating room team should be able to execute from memory, without hesitation, because a burning endotracheal tube inside a patient's airway is one of the few true self-evident emergencies in anesthesia practice.

• Seconds: Time to airway injury (once ETT/fuel ignites)
• Stop gas flow: First action required (remove the oxidizer instantly)
• Saline / water: Extinguishing agent (never alcohol-based fluids)
• 4: Algorithm steps (stop gas → remove → extinguish → reassess)

The four-step immediate fire response algorithm

When a fire is recognized in or near the airway, the entire team executes a rehearsed, near-simultaneous sequence rather than a single individual acting alone:

1. Stop the flow of airway gases immediately — disconnect the breathing circuit or turn off all gas flow (oxygen and nitrous oxide) at the source. This removes the oxidizer leg of the triangle instantly and is the single highest-yield action, since a fire cannot sustain itself once its oxygen supply collapses.

2. Remove the burning material — if the endotracheal tube itself is on fire, remove it from the airway immediately, along with any other burning material (drapes, sponges) in or near the surgical field. Removing the fuel source stops ongoing combustion and prevents further thermal injury to the airway.

3. Extinguish any residual flame with saline or water — poured or irrigated directly onto the burning material and into the airway if the ETT was involved, never with alcohol-based or other flammable fluids. Saline is kept immediately available at the field specifically for this purpose in any case flagged as high fire risk.

4. Remove drapes if they are involved or contaminated with burning debris, assess the patient and the field for residual fire or smoldering material, and only then re-establish ventilation — by mask or by reintubation with a new tube — once the team has confirmed no further ignition risk remains.

This sequence deliberately prioritizes stopping the oxidizer and removing the fuel before anything else, including before attempting to re-establish ventilation, because continuing to deliver oxygen into an active fire — even briefly, while attempting to reintubate — can turn a contained ignition into a blowtorch effect down the trachea and bronchi.

The blowtorch effect: an ignited endotracheal tube with oxygen still flowing through it does not simply burn at the surface — the flame is driven down the tube lumen by the gas flow like a torch, directing thermal injury deep into the trachea and bronchi within seconds. This is precisely why stopping gas flow is always the first step, before any attempt to remove or replace the tube.

Team roles and communication during an active OR fire

A well-rehearsed fire response assigns implicit roles based on position rather than waiting for verbal delegation, since seconds matter:

• Anesthesia team: disconnects/stops gas flow, prepares to manage the airway once the fire is out, monitors the patient's cardiovascular and respiratory status throughout, and prepares for reintubation with fresh equipment.

• Surgical team: removes burning material from the field, applies saline/water to extinguish, and clears drapes and debris away from the airway and face.

• Circulating nurse/team: calls for help, retrieves additional saline or a fire extinguisher if the fire is not immediately controlled by saline alone, and documents the timeline as it unfolds for later debrief.

Because the fire triangle in an airway fire often involves oxygen still flowing at the moment of ignition, the "announce and act" model — the first person to recognize the fire calling it out loudly ("fire!") while simultaneously beginning their own role in the algorithm — is preferred over waiting for a single leader to direct each step individually.

Post-Fire Patient Assessment, Safe Reventilation, and Structured Debrief

Once a surgical fire is extinguished, the clinical and institutional response has only begun. The patient must be thoroughly assessed for thermal airway injury before any assumption of a benign outcome, ventilation must be re-established through a deliberate and safe process, and the event requires a structured multidisciplinary debrief consistent with ASA guidance and Joint Commission sentinel-event review to identify and correct the contributing factors before the next case.

• Bronchoscopy: Airway injury assessment (to evaluate soot, edema, burns)
• New, clean airway: Reventilation approach (after fire source fully removed)
• Sentinel event: Reportable event category (Joint Commission classification)
• Immediate + 24–72h: Debrief window (hot debrief, then formal RCA)

Assessing the patient for airway and burn injury

Even when a fire appears to have been extinguished quickly, thermal injury to the airway can be present without obvious external signs, and its full extent may not be apparent immediately. Post-fire assessment should include:

• Direct laryngoscopy and, where an airway fire occurred, flexible bronchoscopy to inspect the trachea and proximal bronchi for soot deposition, mucosal edema, erythema, or frank burns — findings that indicate the need for prolonged intubation, corticosteroids, or ICU-level airway monitoring.

• Examination of the face, periorbital area, and any skin adjacent to the surgical field for thermal burns, particularly when the fire involved facial drapes or prep solution.

• Continuous monitoring of oxygen saturation, airway resistance, and signs of evolving airway edema or laryngospasm over the following hours, since post-thermal airway swelling can progress after the initial event.

• Documentation of the extent of any burn injury using standard burn assessment tools if skin involvement occurred, with appropriate surgical/burn service consultation.

Only after this assessment confirms the airway is safe should the team proceed with re-establishing planned ventilation — using new, uncontaminated equipment rather than any tube or circuit that was involved in the fire.

Structured debrief and root-cause analysis

A surgical fire is treated as a sentinel or reportable safety event at most institutions, triggering both an immediate "hot" debrief and a subsequent formal root-cause analysis:

• Immediate hot debrief: conducted with the full OR team shortly after the patient is stabilized, while details are fresh — reviewing the sequence of events, what was done well, and what needs to change before the next high-risk case that day.

• Formal root-cause analysis (RCA), typically within 24–72 hours: a structured, blame-free review examining the contributing factors across the fire triangle — was FiO2 higher than necessary, was the ignition device activated before confirming oxygen was minimized, was fuel (prep solution, drapes) inadequately managed — as well as systems factors such as checklist compliance, communication gaps, and equipment availability (was saline immediately at hand?).

• Reporting: consistent with ASA guidance and Joint Commission sentinel-event requirements, the event is documented and reported through the institution's patient safety reporting system, and, where appropriate, to external bodies tracking surgical fire incidence to improve national prevention guidance.

• Corrective actions: findings from the RCA feed back into institutional fire-risk checklists, simulation-based team training, and equipment placement standards (e.g., ensuring saline is always immediately available at the field for any case flagged high risk) — closing the loop from a single adverse event to systemic prevention.

The ASA Practice Advisory and Joint Commission both frame surgical fires as largely preventable events. A structured post-event debrief is not a formality — closed-claims analyses repeatedly show that the same contributing factors (uncontrolled FiO2, inadequate prep drying time, premature ignition-device activation, absent saline at the field) recur across cases, meaning consistent debrief and checklist reinforcement is what actually drives the incidence of OR fires down over time.