How Surgical Fires Start

Surgical fires are fires that occur in, on or around a patient who is undergoing a medical or surgical procedure. Surgical fires can occur any time all three elements of the fire triangle are present:
 

1. Ignition source (for example, electrosurgical units (ESUs), lasers, and fiberoptic light sources)
2. Fuel source (for example, surgical drapes, alcohol-based skin preparation agents, the patient)
3. Oxidizer (for example, oxygen, nitrous oxide, room air) 

Materials that may not burn in room air can ignite easily and burn fiercely in an oxygen-enriched environment (a situation when the concentration of oxygen is greater than in ordinary room air).  In fact, most surgical fires occur in an oxygen-enriched environment.

Other factors also increase the risk of fire. For example, alcohol-based skin preparation agents are very flammable when still wet. The placement of surgical drapes (such as when they are placed in a way that allows oxygen to pool under them), and the handling of ignition sources (such as resting hot ignition sources on the drapes) may also increase the chance that a surgical fire will occur. 

Fires burn hotter and faster in an oxygen enriched environment.  The image above shows a nasal cannula set on fire in room air (left) and in an oxygen enriched environment (right). Courtesy of Anesthesia Patient Safety Foundation.