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Supplemental Oxygen Versus Latent Alcohol Vapors as Surgical Fire Precursors

Barker, Steven J., PhD, MD

doi: 10.1097/00000539-200211000-00081
LETTERS TO THE EDITOR: Letters & Announcements

Department of Anesthesiology

University of Arizona

Tucson, Arizona

In Response:

I welcome Mr. Bruley’s comments on our article, “Fire in the Operating Room: A Case Report and Laboratory Study.” Although I am pleased to see further discussion of the possible mechanisms of our fire, I do not find the mechanism proposed by Bruley to be plausible, for the following reasons.

There is no doubt that the 100% oxygen delivered to the patient via open mask at 6L/min played a key role in the fire. But oxygen must combine with fuel to produce combustion. In our laboratory experiment, the fuel was proven to be the alcohol vapor resulting from the volatile prep solution. In Bruley’s hypothesis, the fuel is apparently a combination of “lint” from the surgical towels and perhaps body hair. This idea is not consistent with two observations made during the fire—that the surgical towels themselves were not involved in the combustion (in fact, they were used to extinguish the fire) and that the fire continued to burn for a few seconds after the towels were removed (observers stated that the patient’s head was “in a ball of flame”). Furthermore, the same surgical towels were used in the laboratory experiment, and they did not burn at all in the absence of the alcohol prep solution.

In response to Bruley’s four criticisms of our experiments, I would note several things. First, using a body-temperature manikin would only increase the volatility of the alcohol, thereby making it a more effective fuel. Second, the experiments were performed under a fume hood, where the air exchange rate was even greater than that of an operating room. Besides, I do not see how this has any bearing on the processes that are occurring under the surgical drapes. Third, the aluminum plate (not foil) was used only to complete an electrical circuit so that the electrocautery could generate a spark. There is no argument about the fact that the ESU provided the ignition source for the fire. Fourth, the gas flows under the experiment drapes closely represented the gas flows that would have occurred near the patient. There is also no dispute of the fact that high oxygen concentrations were present at the site of ignition.

As Mr. Bruley notes his excellent qualifications in the field of fire research, I should at least mention my own background. My PhD is in the field of fluid dynamics, from the California Institute of Technology, and I have published over 20 articles and abstracts in the field of liquid and gas flows.

Steven J. Barker, PhD, MD

© 2002 International Anesthesia Research Society