OR Fire Safety Video Commentary for the Anesthesia Professional


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The most notable finding when cases of operating room fires are reviewed is that most if not all are preventable! This video is intended to promote the best practices known to prevent the potentially devastating complication of a fire in the operating room. Each member of the operating room care team has a role to play in preventing operating room fires. The following commentary is intended to put the recommendations in the video into the context of current practice.

FOR THE ANESTHESIA PROFESSIONAL (prepared by Drs. Jeffrey M. Feldman and Robert K. Stoelting)

Minimizing or eliminating enriched oxygen delivery is fundamental to preventing operating room fires. An increased oxygen concentration in the surgical field is either a direct cause or a significant factor in many operating room fires – particularly procedures involving the head, neck, and upper chest.

The recommendation to eliminate open delivery of oxygen when sedating patients is the most striking practice change advocated in the fire prevention video. This is particularly a consideration for anesthesia professionals since they typically control oxygen administration. For most anesthesia professionals, oxygen administration by nasal cannula or mask (open oxygen delivery) is routine when providing sedation, and is a fundamental strategy for preventing hypoxemia. The recommendations in the video can help the anesthesia professional balance the risks and benefits of oxygen delivery for the individual patient. For patients in whom an increased oxygen concentration cannot be avoided, the video describes strategies that can minimize the risk of an operating room fire.

The following sections address frequently asked questions about the relationship between supplemental oxygen delivery and fire safety

Does the Patient Require Supplemental Oxygen?

This is the first question that the anesthesia professional should consider when developing a plan to minimize the risk of fire. The answer to this question will be based upon an understanding of the patient’s underlying pulmonary function and the depth of sedation that will be required to facilitate the surgical procedure. Patients who are oxygen dependent and have reduced oxyhemoglobin saturation while breathing room air are not candidates for sedation without supplemental oxygen. For such patients, safe care usually requires control of the airway or careful control of oxygen concentration in the surgical field (see below). For patients with normal pulmonary function, it may be possible to administer sedatives and narcotics without administering supplemental oxygen, depending upon the amount and type of medications that are used.

How can I accomplish room air sedation safely?

Safe room air sedation can be accomplished by selecting patients with normal pulmonary function, by administering sedatives and narcotics carefully, and by monitoring oxyhemoglobin saturation continuously.

Room air sedation is most likely to be successful if the surgical procedure is not very painful, or if local anesthetics can be used to reduce or eliminate painful stimulation. In such cases, patient comfort can be assured by titrating sedative medications and opioids in a manner that minimizes the risk of respiratory depression. As surgical stimulation becomes more painful, it becomes increasingly difficult to keep the patient still and comfortable without using doses of sedatives and opioids that lead to respiratory depression and create a need for supplemental oxygen and/or assisted ventilation. Patients who are especially anxious may require larger doses of sedative medications, resulting in respiratory depression and the need for supplemental oxygen and/or assisted ventilation.

Sedatives and opioids should be selected and used in a way that minimizes the risk of respiratory depression. Local anesthetics should be used as effectively as possible to avoid the unnecessary use of opioids. Drugs should be given by incremental titration, allowing sufficient time between doses to assess and manage drug effects before administering additional medication. Careful titration may increase the time needed to prepare the patient for the start of the procedure. Production pressure should not be the reason for hasty bolus administration that results in the need for oxygen administration and an increased risk of fire.

Oxyhemoglobin saturation monitoring by continuous pulse oximetry is essential to safe patient care. However, a saturation reading of 100% is not always necessary. Drug effects that lead to mild respiratory depression with a resulting but stable decrease in saturation as low as 92% may be consistent with safe care. Saturation values of 90% or less are usually undesirable because the steep portion of the oxyhemoglobin dissociation curve puts the patient at risk for rapid desaturation. Assuring continuous pulse oximetry monitoring requires attention to probe placement, including minimizing patient movement at the probe site and possibly insulating the probe from ambient light. If pulse oximeter measurement becomes unreliable during sedation, the procedure should stop until reliable measurement can be restored.

If room air sedation cannot be accomplished, is tracheal intubation necessary?

The most important anesthesia strategy for preventing operating room fires is to minimize the risk that an enriched oxygen concentration will be present at the source of heat (e.g. electrosurgical cautery or laser). If an oxygen concentration greater than 30% is required to prevent hypoxemia during sedation, then controlling the patient’s airway should be strongly considered – especially for procedures around the head, neck and chest. Tracheal intubation is a reliable method for confining an enriched oxygen concentration to the breathing circuit and the lungs. A laryngeal mask airway can also be effective for this purpose, but may not be as reliable as tracheal intubation. Other strategies that minimize the risk of an enriched oxygen concentration in the surgical field include open draping (wide exposure of the surgical site to the atmosphere) and blowing air over the patient’s face to wash out extra oxygen. Open draping and blowing air are not as reliable as tracheal intubation or a laryngeal mask airway because oxygen concentration cannot be measured routinely at the surgical site; thus, it is not possible to make a reliable decision that oxygen concentration is as low as desired before the heat source is activated.

When using open oxygen delivery, can I prevent operating room fires by carefully controlling the oxygen concentration delivered to the patient?

Rapid and widespread propagation of fire – “flash fire” – is minimized if oxygen concentration is less than 30%. The video describes several methods for the open delivery of oxygen at concentrations of 30% or less. These methods have advantages and disadvantages, and may not be easy to implement in some anesthesia locations. Table 1 outlines the five basic options for controlling oxygen concentration in an open system. Table 2 shows flows of oxygen and air that produce a gas blend with an oxygen concentration of 30%.

Several points merit emphasis. In general, the auxiliary flowmeter on the anesthesia machine is only capable of delivering 100% oxygen; it should not be used for open delivery of a controlled oxygen concentrations of 30% or less. An exception is the AS3000 (Mindray Datascope Corporation., Mahwah, NJ) which is available with a flowmeter for blending oxygen and air to deliver an oxygen concentration from 21% to 100%. If open delivery of a controlled oxygen concentration of 30% or less is desired, it is best to deliver this concentration from the start. If the delivered oxygen concentration is reduced to 30% at some time after a higher concentration of oxygen has been started, a higher-than-desired concentration of oxygen may persist for a time at the surgical site or under the drapes.

Table 1: Methods for controlling the delivered oxygen concentration through an open delivery system

Option Pros Cons How to Use
Direct connection to common gas outlet (CGO)
  • Readily available in some anesthetizing locations, depending on the anesthesia machine
  • Highly accurate control of gases delivered to the patient
  • Gas supply to anesthesia circuit is interrupted, which is problematic if the circuit is needed for positive pressure ventilation
  • Actual Oxygen concentration is not measured
  • Easy to deliver oxygen > 30% if air and oxygen are mixed
  • Nitrous oxide can mistakenly be delivered
  • A connector is needed to adapt the CGO to the delivery system
  • Only enough oxygen flow should be added to the air to get the desired concentration (see Table 2)
  • Important reminder: Do not turn on the nitrous oxide
Anesthesia breathing circuit
  • Readily available in all anesthetizing locations
  • Highly accurate control of gases delivered to the circuit
  • Oxygen concentration measured is in the inspired gas
  • At typically used flows (2-4 L/min) the rate of change of gas concentration in the circuit is slow
  • APL valve must be closed to deliver gas to the patient and the reservoir bag will distend
  • The flow of oxygen and air must be carefully adjusted and monitored to avoid a blend with an oxygen concentration > 30% (see Table 2)
  • Carbon dioxide absorbent will dry out over time
  • Nitrous oxide can mistakenly be delivered
  • Start with desired oxygen concentration.
  • Leave time to flush the circuit if oxygen used previously
  • A connector is needed to adapt the circuit to the delivery system
  • Use lower oxygen flows and higher air flows to attain the desired oxygen concentration in the blended gas (see Table 2)
  • Important reminder: Do not turn on the nitrous oxide
Oxygen/Air Blender
  • Most accurate method to control the delivered oxygen concentration
  • Not readily available in most current operating rooms
  • Mounting solutions can be difficult due to the need for compressed gas sources of air and oxygen to the blender
  • Actual oxygen concentration not measured unless using a blender with built in FiO2 monitoring
  • Mount the blender on an IV pole or at another convenient location
  • Connect supply tubing to the blender and sources of compressed oxygen and air
  • Connect the open delivery device to the blender
Venturi system
  • Convenient to use in any location where there is an oxygen flowmeter
  • Actual O2 concentration delivered sensitive to downstream pressure
  • Delivered concentration is not measured
  • Mounting can be a problem
  • Humidified systems require vertical orientation
  • Mount Venturi to an IV pole or another convenient location
  • Select the desired oxygen concentration
  • Turn oxygen flowmeter to desired flow rate
  • Connect open delivery device to the Venturi system
  • Avoid obstruction of delivery system
Oxygen and Air flowmeters connected to auxiliary gas outlet
  • Accurate control of inspired oxygen concentration delivered by auxiliary flowmeter
  • Convenient integration with anesthesia machine
  • Actual delivered concentration is not measured
  • Easy to deliver > 30% when mixing air and oxygen (see Table 2)
  • Availability is limited to one manufacturer (Datascope Anestar(R))
  • Use an anesthesia machine with this capability
  • Connect open delivery device to the outlet for auxiliary flowmeters
  • Only enough oxygen flow should be added to the air to get the desired concentration (Table 2)

Table 2: Oxygen flowmeter setting when mixing with air to achieve an oxygen concentration of 30%

Total Flow (L/min)

Air Flow (L/min)

Oxygen Flow (L/min)













NOTE: The total oxygen flow is significantly less than 1 L/min in all cases. Note that IT IS VERY EASY TO DELIVER TOO MUCH OXYGEN, THEREBY LEADING TO AN OXYGEN CONCENTRATION EXCEEDING 30%. Lower oxygen flows and higher air flows will result in lower oxygen concentrations.

Jeffrey M. Feldman, MD, MSE
Division Chief, General Anesthesia
Children’s Hospital of Philadelphia

Robert K. Stoelting, MD
Anesthesia Patient Safety Foundation