The Doctor’s Advocate | Second Quarter 2015
An Ounce of Prevention

MAC/Sedation Fires Increasing

Susan K. Palmer, MD, The Doctors Company Anesthesia Advisory Board Member

Composite case: A surgeon requested monitored anesthesia care (MAC) for a patient during excisional biopsy of a mole located on the back above the scapula. Oxygen by nasal prongs at 2 L/min resulted in a pulse oximeter reading of O2 96 percent. The anesthesia provider gave bolus of intravenous general anesthesia briefly so that the surgeon could provide wide subcutaneous and intramuscular injections of local anesthetic.

Surgery began, and the awakening patient became uncomfortable due to lateral positioning. The anesthesia provider increased the ongoing propofol infusion and oxygen flow to 6 L/min. The O2 saturation dropped to 87 percent. The anesthesia provider added a vented plastic facemask over the sleeping patient’s mouth and increased oxygen flow to 8 L/min. The surgeon began to use cautery on the patient’s skin edges. Suddenly, the drapes started to blacken and curl, the facemask ignited, and the patient’s hair began rapid incineration. The anesthesia provider quickly removed the drapes, grabbed the mask and tubing from the patient’s face, and turned off the oxygen. The nurses splashed the field and the patient’s face with saline. The patient flailed and then fell off the bed.

Events like OR fires or patient falls should, theoretically, never occur. In addition to causing patient injury, such an occurrence may lead to a malpractice claim and can preclude the involved physicians and hospital from receiving reimbursement for the patient’s ensuing care and treatment. This type of event may also trigger an inspection by the Centers for Medicare and Medicaid Services (CMS), and The Joint Commission (TJC) may determine that a sentinel event has occurred. Both organizations would then require corrections for deficiencies—which would mean that educational and correctional activities must be drafted for CMS/TJC approval. How can this chain of events be prevented?

The Fire Triad

Most anesthesia providers could correctly identify the “fire triad” shown below.

 Fire Trial Image

Most anesthesia providers will not, however, actually witness a sudden surgical fire that injures a patient.

Case reports fill medical literature, and fire safety guidelines in publications may result in readers—with eyes glazed over—responding, “Not another reminder about such a rare problem.” But what most anesthesia providers do not know is that OR fires during MAC cases have actually increased during the last 10 years.1,2 The rapid adjustability of sedation levels that anesthesia providers have learned to deliver with propofol infusion pumps has led to the frequent provision of brief deep sedation/general anesthesia without a secured or isolated airway circuit. Without this secured/isolated airway circuit, the fire triad becomes a reality. An open source of flowing 100 percent oxygen was found to be the cause of 95 percent of all electrocautery-induced OR fires in a 2013 American Society of Anesthesiologists (ASA) Closed Claims study.

The fire in the case outlined in the opening paragraphs would not have occurred if there had been adequate control of oxygen concentration. This single deficiency completed the fire triad. Certainly, the surgeon ignited the fire with an electrocautery device, but his testimony might be imagined as, “I’ve never seen such a thing happen before and had no idea that the anesthesia provider was using oxygen so carelessly.” The anesthesia provider chooses when and how to provide supplemental oxygen and decides whether to put combustible nasal tubing or a plastic facemask on a patient. Therefore, the patient in this case may well blame the anesthesia provider for making the decisions that resulted in the injuries caused by the fire.

A patient’s oxygen saturation during deep sedation can be expected to fall, and an anesthesia provider will usually prefer to provide more oxygen rather than allow the sedation to lighten. This is because anesthesia providers want surgeons to be assured of their ability to produce amnestic and immobile patients. A little extra propofol leads to deeper sedation with lower oxygen saturation, which leads to extra oxygen flow, which leads to an accumulation of greater than 45 percent oxygen in or under drapes, which can ultimately lead to ignition in less than one second3 with a cautery (or a laser or a drill).

Avoid Your First (and Only) OR Fire

Despite recent articles, meeting presentations, and the 2013 revision of the ASA Practice Advisory for Prevention of OR Fires,4 many anesthesia providers have not yet come to appreciate the risks of open source oxygen use in MAC cases. Because combustible materials are always present in an OR,4,5 very high fire risk cases can easily and simply be defined as any case using a source of openly flowing 100 percent oxygen. Consider fire risks before the start of any case that fits this description. 

Other Special Cons

  • Any airway case using greater than 30 percent oxygen.
  • Any case involving surgery above the T6 dermatome, front or back.
  • Any case above T6 dermatome involving an ignition source (for example, Bovie, laser, drill, or heating coil).

Patient Safety Recommendations

  • Never use an open source of oxygen in greater than 30 percent concentration.
  • If a concentration greater than 30 percent is required, consider using an enclosed airway circuit with a laryngeal mask airway (LMA) or endotracheal tube (ETT) for airway management.
  • Use a fresh gas outlet port, attach a small ETT adaptor, attach tubing for nasal prongs or mask to the ETT adaptor, and mix air and O2 to produce a flow of less than 30 percent oxygen.
  • Keep drapes open to the air in order to prevent oxygen accumulation within the drape pockets.


  1. Mehta SP, Bhananker SM, Posner KL, Domino KB. Operating room fires: a closed claims analysis. Anesthesiology. 2013 May;118(5):1133-39.
  2. Bhananker SM, Posner KL, Cheney FW, Caplan RA, Lee LA, Domino KB. Injury and liability associated with monitored anesthesia care: a closed claims analysis. Anesthesiology. 2006 February;104(2):228-34.
  3. Eichhorn JH. A burning issue: preventing patient fires in the operating room. Anesthesiology. 2013 October;119(4): 749-51.
  4. Apfelbaum JL, Caplan RA, Barker SJ, et al. Practice advisory for the prevention and management of operating room fires: an updated report by the American Society of Anesthesiologists Task Force on Operating Room Fires. Anesthesiology. 2013 February;118(2);271-90.
  5. Culp WC Jr, Kimbrough BA, Luna S. Flammability of surgical drapes and materials in varying concentrations of oxygen. Anesthesiology. 2013 October;119(4):770-76.

The Doctor’s Advocate is published by The Doctors Company to advise and inform its members about loss prevention and insurance issues.

The guidelines suggested in this newsletter are not rules, do not constitute legal advice, and do not ensure a successful outcome. They attempt to define principles of practice for providing appropriate care. The principles are not inclusive of all proper methods of care nor exclusive of other methods reasonably directed at obtaining the same results.

The ultimate decision regarding the appropriateness of any treatment must be made by each healthcare provider considering the circumstances of the individual situation and in accordance with the laws of the jurisdiction in which the care is rendered.

The Doctor’s Advocate is published quarterly by Corporate Communications, The Doctors Company. Letters and articles, to be edited and published at the editor’s discretion, are welcome. The views expressed are those of the letter writer and do not necessarily reflect the opinion or official policy of The Doctors Company. Please sign your letters, and address them to the editor.

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