Fire triangle

For a fire to occur, three elements must come together: (1) an oxidizer, (2) fuel, and (3) an ignition source. These three elements are commonly called the “fire triad” and can be represented as a “fire triangle” (Figure 4-1). An OR fire can be prevented by removing any one element of the triangle.

The two oxidizing agents most prevalent in the OR are oxygen (O₂) and nitrous oxide (N₂O). In the OR, many potential fuel sources are present (Box 4-1). The most common ignition source is diathermy or electrocautery with other ignition sources listed in Box 4-1.

Prevention

General OR fire prevention strategies are summarized in Box 4-2 and involve minimizing or avoiding oxidizer-enriched atmospheres, fuels or ignition sources. A useful strategy for prevention of an OR fire is the identification of a high risk procedure, (i.e., a procedure in which an ignition source will be used in proximity to an oxidizer-enriched environment). The presence of an oxidizer (O₂ and N₂O) lowers the combustion threshold and increases the intensity of a fire. This oxidizer-enriched atmosphere exists in (and around) the patient’s breathing circuit and the risk of fire is increased in these areas. The risk of ignition is magnified when certain procedures (e.g., electrosurgery during tracheostomy, cauterization of airway lesions) are performed in close proximity to this environment. A number of techniques can be employed to reduce the fire risk during these high-risk procedures (Box 4-3).

Preparation

The development of a multidisciplinary fire prevention and management plan is an important strategy that can minimize the severity of an OR fire. It involves good communication among all personnel and should begin with a team meeting prior to the patient entering the OR. The meeting should focus on (1) determining whether the procedure has a high risk with regard to fire, and (2) assignment of a specific fire management task that should be performed if a fire did occur.

Management of an operating room fire

An overall strategy for management of an OR fire has been developed by the American Society of Anesthesiologists (Figure 4-2). Once a fire is detected, the surgical procedure should be immediately halted and all OR personnel and appropriate external resources should be notified.

If the fire involves an airway device, ventilation and gas flows should be stopped and the airway device or any burning material should be removed immediately. Saline should be used to extinguish the fire. Once extinguished, a patent airway should be reestablished and ventilation resumed. Reassessment of the patient and situation should occur. Retained intraluminal fragments should be removed by bronchoscopy.

For a non-airway fire, ventilation and gas flows should be stopped. Patient drapes and all burning material should be immediately removed from the patient and saline used to extinguish the fire. Once all burning material has been extinguished, ventilation should be resumed and reassessment of the patient and situation should occur.

Following any fire, the involved personnel should be appropriately debriefed. A review of procedural techniques, including the fire response, should also be conducted.