Mitigating operating room fires: development of a carbon dioxide fire prevention device

Area of Science:

• Surgical Safety
• Biomedical Engineering
• Fire Science

Background:

• Operating room fires are critical safety events, often triggered by electrosurgical unit (ESU) pencils.
• The fire triad (oxidizer, ignition source, fuel) must be present for fires to occur.
• Carbon dioxide (CO2) is a fire suppressant that displaces oxygen.

Purpose of the Study:

• To hypothesize and test a device that generates a CO2 cone around the ESU pencil tip to prevent operating room fires.
• To evaluate the efficacy of a divergent nozzle device delivering CO2 in reducing ignition risk.
• To assess CO2 concentrations in the vicinity of the ESU pencil tip.

Main Methods:

• A divergent nozzle connected to a CO2 source was placed over an ESU pencil.
• Testing was conducted in 21%, 50%, and 100% oxygen environments using a flammability model with laparotomy sponges.
• High-speed videography and CO2 spatial mapping were used to record ignition times and gas concentrations.

Main Results:

• In control trials (no CO2), fires ignited rapidly in all oxygen concentrations (median ignition times ranging from 0.48 to 2.9 seconds).
• With the CO2 device activated, no fires ignited in any test condition (0/15 trials, P < 0.0001).
• CO2 concentrations reached 95% at the ESU tip and 64% approximately 1-1.4 cm away, indicating effective fire suppression.

Conclusions:

• A CO2-delivery device using a divergent nozzle design can effectively prevent fires in a simulated operating room environment.
• The device demonstrated significant risk reduction for operating room fires by creating a localized fire-suppressing atmosphere.
• Further research should optimize CO2 flow rates and nozzle design for maximum patient safety.